[maven-release-plugin] prepare release v0.1.0

The `Refaster` check is now located in the new `refaster-runner` Maven module.

The new `refaster-test-support` module exposes
`RefasterTemplateCollection#validate`, which for a given template collection
validates:
- That there exist corresponding `*Test{Input,Output}.java` files.
- That each template is exercised by precisely one method in these files.

.github/workflows/build.yaml

@@ -0,0 +1,37 @@
+name: Build and verify
+on:
+  pull_request:
+  push:
+    branches:
+      - 'master'
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        jdk: [ 11.0.16, 17.0.4 ]
+    steps:
+        # We run the build twice for each supported JDK: once against the
+        # original Error Prone release, using only Error Prone checks available
+        # on Maven Central, and once against the Picnic Error Prone fork,
+        # additionally enabling all checks defined in this project and any
+        # Error Prone checks available only from other artifact repositories.
+      - name: Check out code
+        uses: actions/checkout@v3.0.2
+      - name: Set up JDK
+        uses: actions/setup-java@v3.4.1
+        with:
+          java-version: ${{ matrix.jdk }}
+          distribution: temurin
+          cache: maven
+      - name: Display build environment details
+        run: mvn --version
+      - name: Build project against vanilla Error Prone
+        run: mvn -T1C install
+      - name: Build project with self-check against Error Prone fork
+        run: mvn -T1C clean verify -Perror-prone-fork -Pnon-maven-central -Pself-check -s settings.xml
+      - name: Remove installed project artifacts
+        run: mvn build-helper:remove-project-artifact
+
+# XXX: Enable Codecov once we "go public".
+# XXX: Enable SonarCloud once we "go public".

.mvn/jvm.config

@@ -1,3 +1,6 @@
+-XX:ReservedCodeCacheSize=512m
+-XX:SoftRefLRUPolicyMSPerMB=10
+-XX:+UseParallelGC
 --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
 --add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
 --add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED

.mvn/maven.config

@@ -0,0 +1 @@
+--batch-mode --errors --strict-checksums

.renovaterc.json

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "packageRules": [
+    {
+      "matchPackagePatterns": [
+        "^org\\.springframework:spring-framework-bom$",
+        "^org\\.springframework\\.boot:spring-boot[a-z-]*$"
+      ],
+      "separateMinorPatch": true
+    },
+    {
+      "matchPackagePatterns": [
+        "^com\\.palantir\\.baseline:baseline-error-prone$"
+      ],
+      "schedule": "* * 1 * *"
+    }
+  ],
+  "reviewers": [
+    "rickie",
+    "Stephan202"
+  ]
+}

.travis.yml

@@ -1,38 +0,0 @@
----
-dist: bionic
-language: java
-jdk: openjdk11
-addons:
-  sonarcloud:
-    organization: picnic-technologies
-    token: "${SONARCLOUD_TOKEN}"
-install:
-  - mvn io.takari:maven:wrapper
-script:
-  # We run the build twice: once against the original Error Prone release,
-  # using only Error Prone checks available on Maven Central, and once against
-  # the Picnic Error Prone fork, additionally enabling all checks defined in
-  # this project and any Error Prone checks available only from other artifact
-  # repositories.
-  - ./mvnw clean install
-  - ./mvnw clean install -Perror-prone-fork -Pnon-maven-central -Pself-check -s settings.xml
-  # XXX: Enable SonarCloud once we "go public".
-  # ./mvnw jacoco:prepare-agent surefire:test jacoco:report sonar:sonar
-  - ./mvnw jacoco:prepare-agent surefire:test jacoco:report
-before_cache:
-  # Don't cache the artifacts we just generated, for multiple reasons: (1) we
-  # shouldn't need them next time around and (2) if we do, that indicates a
-  # dependency issue which might otherwise go unnoticed until next time we bump
-  # the project's version (i.e., when tagging).
-  - find "${HOME}/.m2/repository" -depth -name '*-SNAPSHOT' -exec rm -r '{}' \;
-cache:
-  directories:
-    # The local Maven repository in which third party dependencies are stored.
-    - ${HOME}/.m2/repository
-    # The Takari Maven Wrapper's storage for downloaded Maven distributions.
-    - ${HOME}/.m2/wrapper
-    # The SonarQube analysis cache.
-    - ${HOME}/.sonar/cache
-# XXX: Enable Codecov once we "go public".
-#after_success:
-#  - bash <(curl -s https://codecov.io/bash)

apply-error-prone-suggestions.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+# Compiles the code using Error Prone and applies its suggestions. The set of
+# checks applied can optionally be restricted by name.
+#
+# As this script may modify the project's code, it is important to execute it
+# in a clean Git working directory.
+
+set -e -u -o pipefail
+
+if [ "${#}" -gt 1 ]; then
+  echo "Usage: ./$(basename "${0}") [PatchChecks]"
+  exit 1
+fi
+
+patchChecks=${1:-}
+
+mvn clean test-compile fmt:format \
+  -T 1.0C \
+  -Perror-prone \
+  -Perror-prone-fork \
+  -Ppatch \
+  -Pself-check \
+  -Derror-prone.patch-checks="${patchChecks}" \
+  -Dverification.skip

error-prone-contrib/README.md

@@ -276,10 +276,6 @@ Refaster's expressiveness:
   to be lost. In such a case don't statically import the method, so that the
   generic type information can be retained. (There may be cases where generic
   type information should even be _added_. Find an example.)
-- Upon application of a template Refaster can throw a _No binding for
-  Key{identifier=someAfterTemplateParam}_ exception. When this happens the
-  template is invalid. Instead perform this check at compile time, such that
-  such malformed templates cannot be defined in the first place.
 - Provide a way to express "match if (not) annotated (with _X_)". See #1 for a
   motivating example.
 - Provide a way to place match constraints on compile time constants. For

error-prone-contrib/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.0.1-SNAPSHOT</version>
+        <version>0.1.0</version>
     </parent>
 
     <artifactId>error-prone-contrib</artifactId>
@@ -41,27 +41,24 @@
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
-            <artifactId>migration-util</artifactId>
-            <version>0.0.1-SNAPSHOT</version>
-            <scope>compile</scope>
-        </dependency>
-        <dependency>
-            <groupId>${project.groupId}</groupId>
-            <artifactId>refaster-resource-compiler</artifactId>
-            <!-- This dependency is declared only as a hint to Maven that
-            compilation depends on it; see the `maven-compiler-plugin`'s
-            `annotationProcessorPaths` configuration below. -->
+            <artifactId>refaster-support</artifactId>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
-            <artifactId>refaster-support</artifactId>
+            <artifactId>refaster-test-support</artifactId>
+            <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-annotations</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.auto</groupId>
+            <artifactId>auto-common</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>com.google.auto.service</groupId>
             <artifactId>auto-service-annotations</artifactId>
@@ -77,11 +74,20 @@
             <artifactId>javac</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.google.googlejavaformat</groupId>
+            <artifactId>google-java-format</artifactId>
+        </dependency>
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.newrelic.agent.java</groupId>
+            <artifactId>newrelic-api</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>io.projectreactor</groupId>
             <artifactId>reactor-core</artifactId>
@@ -122,6 +128,11 @@
             <artifactId>jaxb-api</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.aspectj</groupId>
             <artifactId>aspectjweaver</artifactId>
@@ -132,11 +143,6 @@
             <artifactId>assertj-core</artifactId>
             <scope>provided</scope>
         </dependency>
-        <dependency>
-            <groupId>org.hamcrest</groupId>
-            <artifactId>hamcrest-library</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
@@ -167,16 +173,6 @@
             <artifactId>slf4j-api</artifactId>
             <scope>test</scope>
         </dependency>
-        <dependency>
-            <groupId>org.springframework</groupId>
-            <artifactId>spring-beans</artifactId>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>org.springframework</groupId>
-            <artifactId>spring-context</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-test</artifactId>
@@ -192,6 +188,11 @@
             <artifactId>spring-webflux</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-test</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.testng</groupId>
             <artifactId>testng</artifactId>
@@ -202,15 +203,6 @@
     <build>
         <pluginManagement>
             <plugins>
-                <plugin>
-                    <groupId>com.coveo</groupId>
-                    <artifactId>fmt-maven-plugin</artifactId>
-                    <configuration>
-                        <additionalSourceDirectories>
-                            <additionalSourceDirectory>${basedir}/src/test/resources</additionalSourceDirectory>
-                        </additionalSourceDirectories>
-                    </configuration>
-                </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-compiler-plugin</artifactId>
@@ -218,7 +210,7 @@
                         <annotationProcessorPaths combine.children="append">
                             <path>
                                 <groupId>${project.groupId}</groupId>
-                                <artifactId>refaster-resource-compiler</artifactId>
+                                <artifactId>refaster-compiler</artifactId>
                                 <version>${project.version}</version>
                             </path>
                             <path>
@@ -226,14 +218,9 @@
                                 <artifactId>refaster-support</artifactId>
                                 <version>${project.version}</version>
                             </path>
-                            <path>
-                                <groupId>${project.groupId}</groupId>
-                                <artifactId>migration-util</artifactId>
-                                <version>${project.version}</version>
-                            </path>
                         </annotationProcessorPaths>
                         <compilerArgs combine.children="append">
-                            <arg>-Xplugin:RefasterRuleResourceCompiler</arg>
+                            <arg>-Xplugin:RefasterRuleCompiler</arg>
                         </compilerArgs>
                     </configuration>
                 </plugin>

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/AmbiguousJsonCreator.java

@@ -1,12 +1,12 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
 import static com.google.errorprone.matchers.Matchers.isType;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.AnnotationTreeMatcher;
@@ -25,12 +25,11 @@ import javax.lang.model.element.AnnotationValue;
 /** A {@link BugChecker} which flags ambiguous {@code @JsonCreator}s in enums. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "AmbiguousJsonCreator",
     summary = "`JsonCreator.Mode` should be set for single-argument creators",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.LIKELY_ERROR)
-public final class AmbiguousJsonCreatorCheck extends BugChecker implements AnnotationTreeMatcher {
+    linkType = NONE,
+    severity = WARNING,
+    tags = LIKELY_ERROR)
+public final class AmbiguousJsonCreator extends BugChecker implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<AnnotationTree> IS_JSON_CREATOR_ANNOTATION =
       isType("com.fasterxml.jackson.annotation.JsonCreator");

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/AssertJIsNull.java

@@ -0,0 +1,57 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.argument;
+import static com.google.errorprone.matchers.Matchers.argumentCount;
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+import static com.google.errorprone.matchers.Matchers.nullLiteral;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.MethodInvocationTree;
+
+/**
+ * A {@link BugChecker} which flags AssertJ {@code isEqualTo(null)} checks for simplification.
+ *
+ * <p>This bug checker cannot be replaced with a simple Refaster template, as the Refaster approach
+ * would require that all overloads of {@link org.assertj.core.api.Assert#isEqualTo(Object)} (such
+ * as {@link org.assertj.core.api.AbstractStringAssert#isEqualTo(String)}) are explicitly
+ * enumerated. This bug checker generically matches all such current and future overloads.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Prefer `.isNull()` over `.isEqualTo(null)`",
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class AssertJIsNull extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<MethodInvocationTree> ASSERT_IS_EQUAL_TO_NULL =
+      allOf(
+          instanceMethod().onDescendantOf("org.assertj.core.api.Assert").named("isEqualTo"),
+          argumentCount(1),
+          argument(0, nullLiteral()));
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!ASSERT_IS_EQUAL_TO_NULL.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    SuggestedFix.Builder fix =
+        SuggestedFix.builder().merge(SuggestedFixes.renameMethodInvocation(tree, "isNull", state));
+    tree.getArguments().forEach(arg -> fix.merge(SuggestedFix.delete(arg)));
+
+    return describeMatch(tree, fix.build());
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/AutowiredConstructor.java

@@ -1,15 +1,16 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
 import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.isType;
 
 import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
@@ -26,12 +27,11 @@ import java.util.List;
 /** A {@link BugChecker} which flags redundant {@code @Autowired} constructor annotations. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "AutowiredConstructor",
     summary = "Omit `@Autowired` on a class' sole constructor, as it is redundant",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class AutowiredConstructorCheck extends BugChecker implements ClassTreeMatcher {
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class AutowiredConstructor extends BugChecker implements ClassTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final MultiMatcher<Tree, AnnotationTree> AUTOWIRED_ANNOTATION =
       annotations(AT_LEAST_ONE, isType("org.springframework.beans.factory.annotation.Autowired"));
@@ -43,7 +43,7 @@ public final class AutowiredConstructorCheck extends BugChecker implements Class
       return Description.NO_MATCH;
     }
 
-    List<AnnotationTree> annotations =
+    ImmutableList<AnnotationTree> annotations =
         AUTOWIRED_ANNOTATION
             .multiMatchResult(Iterables.getOnlyElement(constructors), state)
             .matchingNodes();

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/CanonicalAnnotationSyntax.java

@@ -1,11 +1,12 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.AnnotationTreeMatcher;
@@ -24,25 +25,24 @@ import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} which flags annotations that could be written more concisely. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "CanonicalAnnotationSyntax",
     summary = "Omit redundant syntax from annotation declarations",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class CanonicalAnnotationSyntaxCheck extends BugChecker
-    implements AnnotationTreeMatcher {
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class CanonicalAnnotationSyntax extends BugChecker implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Pattern TRAILING_ARRAY_COMMA = Pattern.compile(",\\s*}$");
   private static final ImmutableSet<BiFunction<AnnotationTree, VisitorState, Optional<Fix>>>
       FIX_FACTORIES =
           ImmutableSet.of(
-              CanonicalAnnotationSyntaxCheck::dropRedundantParentheses,
-              CanonicalAnnotationSyntaxCheck::dropRedundantValueAttribute,
-              CanonicalAnnotationSyntaxCheck::dropRedundantCurlies);
+              CanonicalAnnotationSyntax::dropRedundantParentheses,
+              CanonicalAnnotationSyntax::dropRedundantValueAttribute,
+              CanonicalAnnotationSyntax::dropRedundantCurlies);
 
   @Override
   public Description matchAnnotation(AnnotationTree tree, VisitorState state) {
@@ -102,7 +102,8 @@ public final class CanonicalAnnotationSyntaxCheck extends BugChecker
     return Optional.of(
         SuggestedFix.replace(
             arg,
-            simplifyAttributeValue(expr, state).orElseGet(() -> Util.treeToString(expr, state))));
+            simplifyAttributeValue(expr, state)
+                .orElseGet(() -> SourceCode.treeToString(expr, state))));
   }
 
   private static Optional<Fix> dropRedundantCurlies(AnnotationTree tree, VisitorState state) {
@@ -137,11 +138,11 @@ public final class CanonicalAnnotationSyntaxCheck extends BugChecker
   private static Optional<String> simplifySingletonArray(NewArrayTree array, VisitorState state) {
     return Optional.of(array.getInitializers())
         .filter(initializers -> initializers.size() == 1)
-        .map(initializers -> Util.treeToString(initializers.get(0), state));
+        .map(initializers -> SourceCode.treeToString(initializers.get(0), state));
   }
 
   private static Optional<String> dropTrailingComma(NewArrayTree array, VisitorState state) {
-    String src = Util.treeToString(array, state);
+    String src = SourceCode.treeToString(array, state);
     return Optional.of(TRAILING_ARRAY_COMMA.matcher(src))
         .filter(Matcher::find)
         .map(m -> src.substring(0, m.start()) + '}');

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/CollectorMutability.java

@@ -0,0 +1,117 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
+import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import java.util.stream.Collector;
+
+/**
+ * A {@link BugChecker} which flags {@link Collector Collectors} that don't clearly express
+ * (im)mutability.
+ *
+ * <p>Replacing such collectors with alternatives that produce immutable collections is preferred.
+ * Do note that Guava's immutable collections are null-hostile.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary =
+        "Avoid `Collectors.to{List,Map,Set}` in favour of alternatives that emphasize (im)mutability",
+    linkType = NONE,
+    severity = WARNING,
+    tags = FRAGILE_CODE)
+public final class CollectorMutability extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> COLLECTOR_METHOD =
+      staticMethod().onClass("java.util.stream.Collectors");
+  private static final Matcher<ExpressionTree> LIST_COLLECTOR =
+      staticMethod().anyClass().named("toList");
+  private static final Matcher<ExpressionTree> MAP_COLLECTOR =
+      staticMethod().anyClass().named("toMap");
+  private static final Matcher<ExpressionTree> SET_COLLECTOR =
+      staticMethod().anyClass().named("toSet");
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!COLLECTOR_METHOD.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    if (LIST_COLLECTOR.matches(tree, state)) {
+      return suggestToCollectionAlternatives(
+          tree, "com.google.common.collect.ImmutableList.toImmutableList", "ArrayList", state);
+    }
+
+    if (MAP_COLLECTOR.matches(tree, state)) {
+      return suggestToMapAlternatives(tree, state);
+    }
+
+    if (SET_COLLECTOR.matches(tree, state)) {
+      return suggestToCollectionAlternatives(
+          tree, "com.google.common.collect.ImmutableSet.toImmutableSet", "HashSet", state);
+    }
+
+    return Description.NO_MATCH;
+  }
+
+  private Description suggestToCollectionAlternatives(
+      MethodInvocationTree tree,
+      String fullyQualifiedImmutableReplacement,
+      String mutableReplacement,
+      VisitorState state) {
+    SuggestedFix.Builder mutableFix = SuggestedFix.builder();
+    String toCollectionSelect =
+        SuggestedFixes.qualifyStaticImport(
+            "java.util.stream.Collectors.toCollection", mutableFix, state);
+
+    return buildDescription(tree)
+        .addFix(replaceMethodInvocation(tree, fullyQualifiedImmutableReplacement, state))
+        .addFix(
+            mutableFix
+                .addImport(String.format("java.util.%s", mutableReplacement))
+                .replace(tree, String.format("%s(%s::new)", toCollectionSelect, mutableReplacement))
+                .build())
+        .build();
+  }
+
+  private Description suggestToMapAlternatives(MethodInvocationTree tree, VisitorState state) {
+    int argCount = tree.getArguments().size();
+    if (argCount > 3) {
+      return Description.NO_MATCH;
+    }
+
+    return buildDescription(tree)
+        .addFix(
+            replaceMethodInvocation(
+                tree, "com.google.common.collect.ImmutableMap.toImmutableMap", state))
+        .addFix(
+            SuggestedFix.builder()
+                .addImport("java.util.HashMap")
+                .postfixWith(
+                    tree.getArguments().get(argCount - 1),
+                    (argCount == 2 ? ", (a, b) -> { throw new IllegalStateException(); }" : "")
+                        + ", HashMap::new")
+                .build())
+        .build();
+  }
+
+  private static SuggestedFix replaceMethodInvocation(
+      MethodInvocationTree tree, String fullyQualifiedReplacement, VisitorState state) {
+    SuggestedFix.Builder fix = SuggestedFix.builder();
+    String replacement = SuggestedFixes.qualifyStaticImport(fullyQualifiedReplacement, fix, state);
+    fix.merge(SuggestedFix.replace(tree.getMethodSelect(), replacement));
+    return fix.build();
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/EmptyMethod.java

@@ -1,5 +1,8 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
 import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.anyOf;
@@ -7,9 +10,6 @@ import static com.google.errorprone.matchers.Matchers.isType;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
@@ -26,12 +26,11 @@ import java.util.Optional;
 /** A {@link BugChecker} which flags empty methods that seemingly can simply be deleted. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "EmptyMethod",
     summary = "Empty method can likely be deleted",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class EmptyMethodCheck extends BugChecker implements MethodTreeMatcher {
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class EmptyMethod extends BugChecker implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<Tree> PERMITTED_ANNOTATION =
       annotations(

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ErrorProneTestHelperSourceFormat.java

@@ -0,0 +1,160 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.STYLE;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+import static java.util.stream.Collectors.joining;
+
+import com.google.auto.service.AutoService;
+import com.google.common.base.Splitter;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.google.googlejavaformat.java.Formatter;
+import com.google.googlejavaformat.java.FormatterException;
+import com.google.googlejavaformat.java.ImportOrderer;
+import com.google.googlejavaformat.java.JavaFormatterOptions.Style;
+import com.google.googlejavaformat.java.RemoveUnusedImports;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.Tree;
+import com.sun.tools.javac.util.Position;
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * A {@link BugChecker} which flags improperly formatted Error Prone test code.
+ *
+ * <p>All test code should be formatted in accordance with Google Java Format's {@link Formatter}
+ * output, and imports should be ordered according to the {@link Style#GOOGLE Google} style.
+ *
+ * <p>This checker inspects inline code passed to {@code
+ * com.google.errorprone.CompilationTestHelper} and {@code
+ * com.google.errorprone.BugCheckerRefactoringTestHelper}. It requires that this code is properly
+ * formatted and that its imports are organized. Only code that represents the expected output of a
+ * refactoring operation is allowed to have unused imports, as most {@link BugChecker}s do not (and
+ * are not able to) remove imports that become obsolete as a result of applying their suggested
+ * fix(es).
+ */
+// XXX: Once we target JDK 17 (optionally?) suggest text block fixes.
+// XXX: GJF guesses the line separator to be used by inspecting the source. When using text blocks
+// this may cause the current unconditional use of `\n` not to be sufficient when building on
+// Windows; TBD.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Test code should follow the Google Java style",
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = STYLE)
+public final class ErrorProneTestHelperSourceFormat extends BugChecker
+    implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Formatter FORMATTER = new Formatter();
+  private static final Matcher<ExpressionTree> INPUT_SOURCE_ACCEPTING_METHOD =
+      anyOf(
+          instanceMethod()
+              .onDescendantOf("com.google.errorprone.CompilationTestHelper")
+              .named("addSourceLines"),
+          instanceMethod()
+              .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper")
+              .named("addInputLines"));
+  private static final Matcher<ExpressionTree> OUTPUT_SOURCE_ACCEPTING_METHOD =
+      instanceMethod()
+          .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper.ExpectOutput")
+          .named("addOutputLines");
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    boolean isOutputSource = OUTPUT_SOURCE_ACCEPTING_METHOD.matches(tree, state);
+    if (!isOutputSource && !INPUT_SOURCE_ACCEPTING_METHOD.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    List<? extends ExpressionTree> sourceLines =
+        tree.getArguments().subList(1, tree.getArguments().size());
+    if (sourceLines.isEmpty()) {
+      return buildDescription(tree).setMessage("No source code provided").build();
+    }
+
+    int startPos = ASTHelpers.getStartPosition(sourceLines.get(0));
+    int endPos = state.getEndPosition(sourceLines.get(sourceLines.size() - 1));
+
+    /* Attempt to format the source code only if it fully consists of constant expressions. */
+    return getConstantSourceCode(sourceLines)
+        .map(source -> flagFormattingIssues(startPos, endPos, source, isOutputSource, state))
+        .orElse(Description.NO_MATCH);
+  }
+
+  private Description flagFormattingIssues(
+      int startPos, int endPos, String source, boolean retainUnusedImports, VisitorState state) {
+    Tree methodInvocation = state.getPath().getLeaf();
+
+    String formatted;
+    try {
+      formatted = formatSourceCode(source, retainUnusedImports).trim();
+    } catch (FormatterException e) {
+      return buildDescription(methodInvocation)
+          .setMessage(String.format("Source code is malformed: %s", e.getMessage()))
+          .build();
+    }
+
+    if (source.trim().equals(formatted)) {
+      return Description.NO_MATCH;
+    }
+
+    if (startPos == Position.NOPOS || endPos == Position.NOPOS) {
+      /*
+       * We have insufficient source information to emit a fix, so we only flag the fact that the
+       * code isn't properly formatted.
+       */
+      return describeMatch(methodInvocation);
+    }
+
+    /*
+     * The code isn't properly formatted; replace all lines with the properly formatted
+     * alternatives.
+     */
+    return describeMatch(
+        methodInvocation,
+        SuggestedFix.replace(
+            startPos,
+            endPos,
+            Splitter.on('\n')
+                .splitToStream(formatted)
+                .map(state::getConstantExpression)
+                .collect(joining(", "))));
+  }
+
+  private static String formatSourceCode(String source, boolean retainUnusedImports)
+      throws FormatterException {
+    String withReorderedImports = ImportOrderer.reorderImports(source, Style.GOOGLE);
+    String withOptionallyRemovedImports =
+        retainUnusedImports
+            ? withReorderedImports
+            : RemoveUnusedImports.removeUnusedImports(withReorderedImports);
+    return FORMATTER.formatSource(withOptionallyRemovedImports);
+  }
+
+  private static Optional<String> getConstantSourceCode(
+      List<? extends ExpressionTree> sourceLines) {
+    StringBuilder source = new StringBuilder();
+
+    for (ExpressionTree sourceLine : sourceLines) {
+      Object value = ASTHelpers.constValue(sourceLine);
+      if (value == null) {
+        return Optional.empty();
+      }
+
+      source.append(value).append('\n');
+    }
+
+    return Optional.of(source.toString());
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ExplicitEnumOrdering.java

@@ -2,6 +2,9 @@ package tech.picnic.errorprone.bugpatterns;
 
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.ImmutableSetMultimap.toImmutableSetMultimap;
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 import static java.util.stream.Collectors.collectingAndThen;
 
@@ -12,9 +15,6 @@ import com.google.common.collect.Multimaps;
 import com.google.common.collect.Ordering;
 import com.google.common.collect.Sets;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
@@ -35,13 +35,11 @@ import java.util.stream.Stream;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "ExplicitEnumOrdering",
     summary = "Make sure `Ordering#explicit` lists all of an enum's values",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.FRAGILE_CODE)
-public final class ExplicitEnumOrderingCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+    linkType = NONE,
+    severity = WARNING,
+    tags = FRAGILE_CODE)
+public final class ExplicitEnumOrdering extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> EXPLICIT_ORDERING =
       staticMethod().onClass(Ordering.class.getName()).named("explicit");
@@ -73,7 +71,7 @@ public final class ExplicitEnumOrderingCheck extends BugChecker
         .collect(
             collectingAndThen(
                 toImmutableSetMultimap(Symbol::asType, Symbol::toString),
-                ExplicitEnumOrderingCheck::getMissingEnumValues));
+                ExplicitEnumOrdering::getMissingEnumValues));
   }
 
   private static ImmutableSet<String> getMissingEnumValues(

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FluxFlatMapUsage.java

@@ -0,0 +1,85 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
+import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.Iterables;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MemberReferenceTreeMatcher;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MemberReferenceTree;
+import com.sun.source.tree.MethodInvocationTree;
+import java.util.function.Function;
+import java.util.function.Supplier;
+import reactor.core.publisher.Flux;
+
+/**
+ * A {@link BugChecker} which flags usages of {@link Flux#flatMap(Function)} and {@link
+ * Flux#flatMapSequential(Function)}.
+ *
+ * <p>{@link Flux#flatMap(Function)} and {@link Flux#flatMapSequential(Function)} eagerly perform up
+ * to {@link reactor.util.concurrent.Queues#SMALL_BUFFER_SIZE} subscriptions. Additionally, the
+ * former interleaves values as they are emitted, yielding nondeterministic results. In most cases
+ * {@link Flux#concatMap(Function)} should be preferred, as it produces consistent results and
+ * avoids potentially saturating the thread pool on which subscription happens. If {@code
+ * concatMap}'s single-subscription semantics are undesirable one should invoke a {@code flatMap} or
+ * {@code flatMapSequential} overload with an explicit concurrency level.
+ *
+ * <p>NB: The rarely-used overload {@link Flux#flatMap(Function, Function, Supplier)} is not flagged
+ * by this check because there is no clear alternative to point to.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary =
+        "`Flux#flatMap` and `Flux#flatMapSequential` have subtle semantics; "
+            + "please use `Flux#concatMap` or explicitly specify the desired amount of concurrency",
+    linkType = NONE,
+    severity = ERROR,
+    tags = LIKELY_ERROR)
+public final class FluxFlatMapUsage extends BugChecker
+    implements MethodInvocationTreeMatcher, MemberReferenceTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final String MAX_CONCURRENCY_ARG_NAME = "MAX_CONCURRENCY";
+  private static final Matcher<ExpressionTree> FLUX_FLATMAP =
+      instanceMethod()
+          .onDescendantOf("reactor.core.publisher.Flux")
+          .namedAnyOf("flatMap", "flatMapSequential")
+          .withParameters(Function.class.getName());
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!FLUX_FLATMAP.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    return buildDescription(tree)
+        .addFix(SuggestedFixes.renameMethodInvocation(tree, "concatMap", state))
+        .addFix(
+            SuggestedFix.builder()
+                .postfixWith(
+                    Iterables.getOnlyElement(tree.getArguments()), ", " + MAX_CONCURRENCY_ARG_NAME)
+                .build())
+        .build();
+  }
+
+  @Override
+  public Description matchMemberReference(MemberReferenceTree tree, VisitorState state) {
+    if (!FLUX_FLATMAP.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    // Method references are expected to occur very infrequently; generating both variants of
+    // suggested fixes is not worth the trouble.
+    return describeMatch(tree);
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FormatStringConcatenation.java

@@ -1,5 +1,8 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.allOf;
 import static com.google.errorprone.matchers.Matchers.anyMethod;
 import static com.google.errorprone.matchers.Matchers.anyOf;
@@ -10,9 +13,6 @@ import static java.util.stream.Collectors.joining;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
@@ -31,6 +31,8 @@ import com.sun.source.util.SimpleTreeVisitor;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
+import javax.annotation.Nullable;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags string concatenations that produce a format string; in such
@@ -48,12 +50,11 @@ import java.util.Optional;
 // invocations, as necessary.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "FormatStringConcatenation",
     summary = "Defer string concatenation to the invoked method",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.SIMPLIFICATION)
-public final class FormatStringConcatenationCheck extends BugChecker
+    linkType = NONE,
+    severity = WARNING,
+    tags = SIMPLIFICATION)
+public final class FormatStringConcatenation extends BugChecker
     implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   /**
@@ -210,6 +211,7 @@ public final class FormatStringConcatenationCheck extends BugChecker
       this.formatSpecifier = formatSpecifier;
     }
 
+    @Nullable
     @Override
     public Void visitBinary(BinaryTree tree, VisitorState state) {
       if (tree.getKind() == Kind.PLUS && isStringTyped(tree, state)) {
@@ -222,11 +224,13 @@ public final class FormatStringConcatenationCheck extends BugChecker
       return null;
     }
 
+    @Nullable
     @Override
     public Void visitParenthesized(ParenthesizedTree tree, VisitorState state) {
       return tree.getExpression().accept(this, state);
     }
 
+    @Nullable
     @Override
     protected Void defaultAction(Tree tree, VisitorState state) {
       appendExpression(tree);
@@ -246,7 +250,7 @@ public final class FormatStringConcatenationCheck extends BugChecker
       return state.getConstantExpression(formatString.toString())
           + ", "
           + formatArguments.stream()
-              .map(tree -> Util.treeToString(tree, state))
+              .map(tree -> SourceCode.treeToString(tree, state))
               .collect(joining(", "));
     }
   }

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/IdentityConversion.java

@@ -0,0 +1,110 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.staticMethod;
+import static com.google.errorprone.suppliers.Suppliers.OBJECT_TYPE;
+
+import com.google.auto.service.AutoService;
+import com.google.common.primitives.Primitives;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.bugpatterns.TypesWithUndefinedEquality;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.google.errorprone.util.ASTHelpers.TargetType;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.tools.javac.code.Type;
+import com.sun.tools.javac.code.Types;
+import java.util.Arrays;
+import java.util.List;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+
+/** A {@link BugChecker} that flags redundant identity conversions. */
+// XXX: Consider detecting cases where a flagged expression is passed to a method, and where removal
+// of the identify conversion would cause a different method overload to be selected. Depending on
+// the target method such a modification may change the code's semantics or performance.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Avoid or clarify identity conversions",
+    linkType = NONE,
+    severity = WARNING,
+    tags = SIMPLIFICATION)
+public final class IdentityConversion extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> IS_CONVERSION_METHOD =
+      anyOf(
+          staticMethod()
+              .onClassAny(
+                  "com.google.common.collect.ImmutableBiMap",
+                  "com.google.common.collect.ImmutableList",
+                  "com.google.common.collect.ImmutableListMultimap",
+                  "com.google.common.collect.ImmutableMap",
+                  "com.google.common.collect.ImmutableMultimap",
+                  "com.google.common.collect.ImmutableMultiset",
+                  "com.google.common.collect.ImmutableRangeMap",
+                  "com.google.common.collect.ImmutableRangeSet",
+                  "com.google.common.collect.ImmutableSet",
+                  "com.google.common.collect.ImmutableSetMultimap",
+                  "com.google.common.collect.ImmutableTable")
+              .named("copyOf"),
+          staticMethod()
+              .onClassAny(
+                  Primitives.allWrapperTypes().stream()
+                      .map(Class::getName)
+                      .collect(toImmutableSet()))
+              .named("valueOf"),
+          staticMethod().onClass(String.class.getName()).named("valueOf"),
+          staticMethod().onClass("reactor.adapter.rxjava.RxJava2Adapter"),
+          staticMethod()
+              .onClass("reactor.core.publisher.Flux")
+              .namedAnyOf("concat", "firstWithSignal", "from", "merge"),
+          staticMethod().onClass("reactor.core.publisher.Mono").namedAnyOf("from", "fromDirect"));
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    List<? extends ExpressionTree> arguments = tree.getArguments();
+    if (arguments.size() != 1 || !IS_CONVERSION_METHOD.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    ExpressionTree sourceTree = arguments.get(0);
+    Type sourceType = ASTHelpers.getType(sourceTree);
+    Type resultType = ASTHelpers.getType(tree);
+    TargetType targetType = ASTHelpers.targetType(state);
+    if (sourceType == null || resultType == null || targetType == null) {
+      return Description.NO_MATCH;
+    }
+
+    if (!state.getTypes().isSameType(sourceType, resultType)
+        && !isConvertibleWithWellDefinedEquality(sourceType, targetType.type(), state)) {
+      return Description.NO_MATCH;
+    }
+
+    return buildDescription(tree)
+        .setMessage(
+            "This method invocation appears redundant; remove it or suppress this warning and "
+                + "add a comment explaining its purpose")
+        .addFix(SuggestedFix.replace(tree, SourceCode.treeToString(sourceTree, state)))
+        .addFix(SuggestedFixes.addSuppressWarnings(state, canonicalName()))
+        .build();
+  }
+
+  private static boolean isConvertibleWithWellDefinedEquality(
+      Type sourceType, Type targetType, VisitorState state) {
+    Types types = state.getTypes();
+    return !types.isSameType(targetType, OBJECT_TYPE.get(state))
+        && types.isConvertible(sourceType, targetType)
+        && Arrays.stream(TypesWithUndefinedEquality.values())
+            .noneMatch(b -> b.matchesType(sourceType, state) || b.matchesType(targetType, state));
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitMethodDeclaration.java

@@ -0,0 +1,201 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.annotations;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.enclosingClass;
+import static com.google.errorprone.matchers.Matchers.hasModifier;
+import static com.google.errorprone.matchers.Matchers.isType;
+import static java.util.function.Predicate.not;
+import static tech.picnic.errorprone.bugpatterns.util.JavaKeywords.isReservedKeyword;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.matchers.Matchers;
+import com.google.errorprone.matchers.MultiMatcher;
+import com.google.errorprone.predicates.TypePredicate;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.AnnotationTree;
+import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.ImportTree;
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.Tree;
+import com.sun.tools.javac.code.Symbol;
+import java.util.Optional;
+import javax.lang.model.element.Modifier;
+import javax.lang.model.element.Name;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+
+/** A {@link BugChecker} which flags non-canonical JUnit method declarations. */
+// XXX: Consider introducing a class-level check which enforces that test classes:
+// 1. Are named `*Test` or `Abstract*TestCase`.
+// 2. If not `abstract`, are package-private and don't have public methods and subclasses.
+// 3. Only have private fields.
+// XXX: If implemented, the current logic could flag only `private` JUnit methods.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "JUnit method declaration can likely be improved",
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class JUnitMethodDeclaration extends BugChecker implements MethodTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final String TEST_PREFIX = "test";
+  private static final ImmutableSet<Modifier> ILLEGAL_MODIFIERS =
+      ImmutableSet.of(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC);
+  private static final Matcher<MethodTree> HAS_UNMODIFIABLE_SIGNATURE =
+      anyOf(
+          annotations(AT_LEAST_ONE, isType("java.lang.Override")),
+          allOf(
+              Matchers.not(hasModifier(Modifier.FINAL)),
+              Matchers.not(hasModifier(Modifier.PRIVATE)),
+              enclosingClass(hasModifier(Modifier.ABSTRACT))));
+  private static final MultiMatcher<MethodTree, AnnotationTree> TEST_METHOD =
+      annotations(
+          AT_LEAST_ONE,
+          anyOf(
+              isType("org.junit.jupiter.api.Test"),
+              hasMetaAnnotation("org.junit.jupiter.api.TestTemplate")));
+  private static final MultiMatcher<MethodTree, AnnotationTree> SETUP_OR_TEARDOWN_METHOD =
+      annotations(
+          AT_LEAST_ONE,
+          anyOf(
+              isType("org.junit.jupiter.api.AfterAll"),
+              isType("org.junit.jupiter.api.AfterEach"),
+              isType("org.junit.jupiter.api.BeforeAll"),
+              isType("org.junit.jupiter.api.BeforeEach")));
+
+  @Override
+  public Description matchMethod(MethodTree tree, VisitorState state) {
+    if (HAS_UNMODIFIABLE_SIGNATURE.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    boolean isTestMethod = TEST_METHOD.matches(tree, state);
+    if (!isTestMethod && !SETUP_OR_TEARDOWN_METHOD.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    SuggestedFix.Builder fixBuilder = SuggestedFix.builder();
+    SuggestedFixes.removeModifiers(tree.getModifiers(), state, ILLEGAL_MODIFIERS)
+        .ifPresent(fixBuilder::merge);
+
+    if (isTestMethod) {
+      suggestTestMethodRenameIfApplicable(tree, fixBuilder, state);
+    }
+
+    return fixBuilder.isEmpty() ? Description.NO_MATCH : describeMatch(tree, fixBuilder.build());
+  }
+
+  private void suggestTestMethodRenameIfApplicable(
+      MethodTree tree, SuggestedFix.Builder fixBuilder, VisitorState state) {
+    tryCanonicalizeMethodName(tree)
+        .ifPresent(
+            newName ->
+                findMethodRenameBlocker(newName, state)
+                    .ifPresentOrElse(
+                        blocker -> reportMethodRenameBlocker(tree, blocker, state),
+                        () -> fixBuilder.merge(SuggestedFixes.renameMethod(tree, newName, state))));
+  }
+
+  private void reportMethodRenameBlocker(MethodTree tree, String reason, VisitorState state) {
+    state.reportMatch(
+        buildDescription(tree)
+            .setMessage(
+                String.format(
+                    "This method's name should not redundantly start with `%s` (but note that %s)",
+                    TEST_PREFIX, reason))
+            .build());
+  }
+
+  /**
+   * If applicable, returns a human-readable argument against assigning the given name to an
+   * existing method.
+   *
+   * <p>This method implements imperfect heuristics. Things it currently does not consider include
+   * the following:
+   *
+   * <ul>
+   *   <li>Whether the rename would merely introduce a method overload, rather than clashing with an
+   *       existing method declaration.
+   *   <li>Whether the rename would cause a method in a superclass to be overridden.
+   *   <li>Whether the rename would in fact clash with a static import. (It could be that a static
+   *       import of the same name is only referenced from lexical scopes in which the method under
+   *       consideration cannot be referenced directly.)
+   * </ul>
+   */
+  private static Optional<String> findMethodRenameBlocker(String methodName, VisitorState state) {
+    if (isMethodInEnclosingClass(methodName, state)) {
+      return Optional.of(
+          String.format("a method named `%s` already exists in this class", methodName));
+    }
+
+    if (isSimpleNameStaticallyImported(methodName, state)) {
+      return Optional.of(String.format("`%s` is already statically imported", methodName));
+    }
+
+    if (isReservedKeyword(methodName)) {
+      return Optional.of(String.format("`%s` is a reserved keyword", methodName));
+    }
+
+    return Optional.empty();
+  }
+
+  private static boolean isMethodInEnclosingClass(String methodName, VisitorState state) {
+    return state.findEnclosing(ClassTree.class).getMembers().stream()
+        .filter(MethodTree.class::isInstance)
+        .map(MethodTree.class::cast)
+        .map(MethodTree::getName)
+        .map(Name::toString)
+        .anyMatch(methodName::equals);
+  }
+
+  private static boolean isSimpleNameStaticallyImported(String simpleName, VisitorState state) {
+    return state.getPath().getCompilationUnit().getImports().stream()
+        .filter(ImportTree::isStatic)
+        .map(ImportTree::getQualifiedIdentifier)
+        .map(tree -> getStaticImportSimpleName(tree, state))
+        .anyMatch(simpleName::contentEquals);
+  }
+
+  private static CharSequence getStaticImportSimpleName(Tree tree, VisitorState state) {
+    String source = SourceCode.treeToString(tree, state);
+    return source.subSequence(source.lastIndexOf('.') + 1, source.length());
+  }
+
+  private static Optional<String> tryCanonicalizeMethodName(MethodTree tree) {
+    return Optional.ofNullable(ASTHelpers.getSymbol(tree))
+        .map(sym -> sym.getQualifiedName().toString())
+        .filter(name -> name.startsWith(TEST_PREFIX))
+        .map(name -> name.substring(TEST_PREFIX.length()))
+        .filter(not(String::isEmpty))
+        .map(name -> Character.toLowerCase(name.charAt(0)) + name.substring(1))
+        .filter(name -> !Character.isDigit(name.charAt(0)));
+  }
+
+  // XXX: Move to a `MoreMatchers` utility class.
+  private static Matcher<AnnotationTree> hasMetaAnnotation(String annotationClassName) {
+    TypePredicate typePredicate = hasAnnotation(annotationClassName);
+    return (tree, state) -> {
+      Symbol sym = ASTHelpers.getSymbol(tree);
+      return sym != null && typePredicate.apply(sym.type, state);
+    };
+  }
+
+  // XXX: Move to a `MoreTypePredicates` utility class.
+  private static TypePredicate hasAnnotation(String annotationClassName) {
+    return (type, state) -> ASTHelpers.hasAnnotation(type.tsym, annotationClassName, state);
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitMethodDeclarationCheck.java

@@ -1,114 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
-import static com.google.errorprone.matchers.Matchers.annotations;
-import static com.google.errorprone.matchers.Matchers.anyOf;
-import static com.google.errorprone.matchers.Matchers.isType;
-import static java.util.function.Predicate.not;
-
-import com.google.auto.service.AutoService;
-import com.google.common.collect.ImmutableSet;
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.bugpatterns.BugChecker;
-import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
-import com.google.errorprone.fixes.SuggestedFix;
-import com.google.errorprone.fixes.SuggestedFixes;
-import com.google.errorprone.matchers.Description;
-import com.google.errorprone.matchers.Matcher;
-import com.google.errorprone.matchers.MultiMatcher;
-import com.google.errorprone.predicates.TypePredicate;
-import com.google.errorprone.util.ASTHelpers;
-import com.sun.source.tree.AnnotationTree;
-import com.sun.source.tree.MethodTree;
-import com.sun.tools.javac.code.Symbol;
-import java.util.Optional;
-import javax.lang.model.element.Modifier;
-
-/** A {@link BugChecker} which flags non-canonical JUnit method declarations. */
-// XXX: Consider introducing a class-level check which enforces that test classes:
-// 1. Are named `*Test` or `Abstract*TestCase`.
-// 2. If not `abstract`, don't have public methods and subclasses.
-// 3. Only have private fields.
-// XXX: If implemented, the current logic could flag only `private` JUnit methods.
-@AutoService(BugChecker.class)
-@BugPattern(
-    name = "JUnitMethodDeclaration",
-    summary = "JUnit method declaration can likely be improved",
-    linkType = BugPattern.LinkType.NONE,
-    severity = BugPattern.SeverityLevel.SUGGESTION,
-    tags = BugPattern.StandardTags.SIMPLIFICATION)
-public final class JUnitMethodDeclarationCheck extends BugChecker implements MethodTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final String TEST_PREFIX = "test";
-  private static final ImmutableSet<Modifier> ILLEGAL_MODIFIERS =
-      ImmutableSet.of(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC);
-  private static final MultiMatcher<MethodTree, AnnotationTree> OVERRIDE_METHOD =
-      annotations(AT_LEAST_ONE, isType("java.lang.Override"));
-  private static final MultiMatcher<MethodTree, AnnotationTree> TEST_METHOD =
-      annotations(
-          AT_LEAST_ONE,
-          anyOf(
-              isType("org.junit.jupiter.api.Test"),
-              hasMetaAnnotation("org.junit.jupiter.api.TestTemplate")));
-  private static final MultiMatcher<MethodTree, AnnotationTree> SETUP_OR_TEARDOWN_METHOD =
-      annotations(
-          AT_LEAST_ONE,
-          anyOf(
-              isType("org.junit.jupiter.api.AfterAll"),
-              isType("org.junit.jupiter.api.AfterEach"),
-              isType("org.junit.jupiter.api.BeforeAll"),
-              isType("org.junit.jupiter.api.BeforeEach")));
-
-  @Override
-  public Description matchMethod(MethodTree tree, VisitorState state) {
-    // XXX: Perhaps we should also skip analysis of non-`private` non-`final` methods in abstract
-    // classes?
-    if (OVERRIDE_METHOD.matches(tree, state)) {
-      return Description.NO_MATCH;
-    }
-
-    boolean isTestMethod = TEST_METHOD.matches(tree, state);
-    if (!isTestMethod && !SETUP_OR_TEARDOWN_METHOD.matches(tree, state)) {
-      return Description.NO_MATCH;
-    }
-
-    SuggestedFix.Builder builder = SuggestedFix.builder();
-    SuggestedFixes.removeModifiers(tree.getModifiers(), state, ILLEGAL_MODIFIERS)
-        .ifPresent(builder::merge);
-
-    if (isTestMethod) {
-      // XXX: In theory this rename could clash with an existing method or static import. In that
-      // case we should emit a warning without a suggested replacement.
-      tryCanonicalizeMethodName(tree, state).ifPresent(builder::merge);
-    }
-
-    return builder.isEmpty() ? Description.NO_MATCH : describeMatch(tree, builder.build());
-  }
-
-  private static Optional<SuggestedFix> tryCanonicalizeMethodName(
-      MethodTree tree, VisitorState state) {
-    return Optional.ofNullable(ASTHelpers.getSymbol(tree))
-        .map(sym -> sym.getQualifiedName().toString())
-        .filter(name -> name.startsWith(TEST_PREFIX))
-        .map(name -> name.substring(TEST_PREFIX.length()))
-        .filter(not(String::isEmpty))
-        .map(name -> Character.toLowerCase(name.charAt(0)) + name.substring(1))
-        .filter(name -> !Character.isDigit(name.charAt(0)))
-        .map(name -> SuggestedFixes.renameMethod(tree, name, state));
-  }
-
-  // XXX: Move to a `MoreMatchers` utility class.
-  private static Matcher<AnnotationTree> hasMetaAnnotation(String annotationClassName) {
-    TypePredicate typePredicate = hasAnnotation(annotationClassName);
-    return (tree, state) -> {
-      Symbol sym = ASTHelpers.getSymbol(tree);
-      return sym != null && typePredicate.apply(sym.type, state);
-    };
-  }
-
-  // XXX: Move to a `MoreTypePredicates` utility class.
-  private static TypePredicate hasAnnotation(String annotationClassName) {
-    return (type, state) -> ASTHelpers.hasAnnotation(type.tsym, annotationClassName, state);
-  }
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationAttributeListing.java

@@ -1,5 +1,8 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.STYLE;
 import static java.util.Comparator.comparing;
 import static java.util.Comparator.naturalOrder;
 import static java.util.stream.Collectors.joining;
@@ -9,9 +12,6 @@ import com.google.common.collect.Comparators;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -37,6 +37,9 @@ import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Stream;
+import javax.annotation.Nullable;
+import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags annotation array listings which aren't sorted lexicographically.
@@ -46,12 +49,11 @@ import java.util.stream.Stream;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "LexicographicalAnnotationAttributeListing",
     summary = "Where possible, sort annotation array attributes lexicographically",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.STYLE)
-public final class LexicographicalAnnotationAttributeListingCheck extends BugChecker
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = STYLE)
+public final class LexicographicalAnnotationAttributeListing extends BugChecker
     implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final ImmutableSet<String> BLACKLISTED_ANNOTATIONS =
@@ -67,17 +69,17 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
 
   private final AnnotationAttributeMatcher matcher;
 
-  /** Instantiates the default {@link LexicographicalAnnotationAttributeListingCheck}. */
-  public LexicographicalAnnotationAttributeListingCheck() {
+  /** Instantiates the default {@link LexicographicalAnnotationAttributeListing}. */
+  public LexicographicalAnnotationAttributeListing() {
     this(ErrorProneFlags.empty());
   }
 
   /**
-   * Instantiates a customized {@link LexicographicalAnnotationAttributeListingCheck}.
+   * Instantiates a customized {@link LexicographicalAnnotationAttributeListing}.
    *
    * @param flags Any provided command line flags.
    */
-  public LexicographicalAnnotationAttributeListingCheck(ErrorProneFlags flags) {
+  public LexicographicalAnnotationAttributeListing(ErrorProneFlags flags) {
     matcher = createAnnotationAttributeMatcher(flags);
   }
 
@@ -128,7 +130,7 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
     /* The elements aren't sorted. Suggest the sorted alternative. */
     String suggestion =
         desiredOrdering.stream()
-            .map(expr -> Util.treeToString(expr, state))
+            .map(expr -> SourceCode.treeToString(expr, state))
             .collect(joining(", ", "{", "}"));
     return Optional.of(SuggestedFix.builder().replace(array, suggestion));
   }
@@ -171,18 +173,21 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
     ImmutableList.Builder<ImmutableList<String>> nodes = ImmutableList.builder();
 
     new TreeScanner<Void, Void>() {
+      @Nullable
       @Override
       public Void visitIdentifier(IdentifierTree node, Void ctx) {
         nodes.add(tokenize(node));
         return super.visitIdentifier(node, ctx);
       }
 
+      @Nullable
       @Override
       public Void visitLiteral(LiteralTree node, Void ctx) {
         nodes.add(tokenize(node));
         return super.visitLiteral(node, ctx);
       }
 
+      @Nullable
       @Override
       public Void visitPrimitiveType(PrimitiveTypeTree node, Void ctx) {
         nodes.add(tokenize(node));
@@ -194,7 +199,7 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
          * Tokens are split on `=` so that e.g. inline Spring property declarations are properly
          * sorted by key, then value.
          */
-        return ImmutableList.copyOf(Util.treeToString(node, state).split("=", -1));
+        return ImmutableList.copyOf(SourceCode.treeToString(node, state).split("=", -1));
       }
     }.scan(array, null);
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationListing.java

@@ -1,15 +1,15 @@
 package tech.picnic.errorprone.bugpatterns;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.STYLE;
 import static java.util.Comparator.comparing;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Streams;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
@@ -20,6 +20,7 @@ import com.sun.source.tree.AnnotationTree;
 import com.sun.source.tree.MethodTree;
 import java.util.List;
 import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} that flags annotations that are not lexicographically sorted.
@@ -29,12 +30,11 @@ import java.util.Optional;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "LexicographicalAnnotationListing",
     summary = "Sort annotations lexicographically where possible",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.STYLE)
-public final class LexicographicalAnnotationListingCheck extends BugChecker
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = STYLE)
+public final class LexicographicalAnnotationListing extends BugChecker
     implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
 
@@ -52,7 +52,7 @@ public final class LexicographicalAnnotationListingCheck extends BugChecker
 
     Optional<Fix> fix = tryFixOrdering(originalOrdering, sortedAnnotations, state);
 
-    Description.Builder description = buildDescription(tree);
+    Description.Builder description = buildDescription(originalOrdering.get(0));
     fix.ifPresent(description::addFix);
     return description.build();
   }
@@ -60,7 +60,7 @@ public final class LexicographicalAnnotationListingCheck extends BugChecker
   private static ImmutableList<? extends AnnotationTree> sort(
       List<? extends AnnotationTree> annotations, VisitorState state) {
     return annotations.stream()
-        .sorted(comparing(annotation -> Util.treeToString(annotation, state)))
+        .sorted(comparing(annotation -> SourceCode.treeToString(annotation, state)))
         .collect(toImmutableList());
   }
 
@@ -72,7 +72,8 @@ public final class LexicographicalAnnotationListingCheck extends BugChecker
             originalAnnotations.stream(),
             sortedAnnotations.stream(),
             (original, replacement) ->
-                SuggestedFix.builder().replace(original, Util.treeToString(replacement, state)))
+                SuggestedFix.builder()
+                    .replace(original, SourceCode.treeToString(replacement, state)))
         .reduce(SuggestedFix.Builder::merge)
         .map(SuggestedFix.Builder::build);
   }

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MethodReferenceUsage.java

@@ -1,14 +1,14 @@
 package tech.picnic.errorprone.bugpatterns;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.STYLE;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.LambdaExpressionTreeMatcher;
@@ -51,13 +51,11 @@ import javax.lang.model.element.Name;
 // Palantir's `LambdaMethodReference` check seems to suffer a similar issue at this time.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "MethodReferenceUsage",
     summary = "Prefer method references over lambda expressions",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.STYLE)
-public final class MethodReferenceUsageCheck extends BugChecker
-    implements LambdaExpressionTreeMatcher {
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = STYLE)
+public final class MethodReferenceUsage extends BugChecker implements LambdaExpressionTreeMatcher {
   private static final long serialVersionUID = 1L;
 
   @Override

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MissingRefasterAnnotation.java

@@ -1,5 +1,8 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
 import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.anyOf;
@@ -7,9 +10,6 @@ import static com.google.errorprone.matchers.Matchers.isType;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.ClassTreeMatcher;
@@ -24,12 +24,11 @@ import com.sun.source.tree.Tree;
 /** A {@link BugChecker} that flags likely missing Refaster annotations. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "MissingRefasterAnnotation",
     summary = "The Refaster template contains a method without any Refaster annotations",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.LIKELY_ERROR)
-public final class MissingRefasterAnnotationCheck extends BugChecker implements ClassTreeMatcher {
+    linkType = NONE,
+    severity = WARNING,
+    tags = LIKELY_ERROR)
+public final class MissingRefasterAnnotation extends BugChecker implements ClassTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final MultiMatcher<Tree, AnnotationTree> REFASTER_ANNOTATION =
       annotations(

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MockitoStubbing.java

@@ -1,13 +1,13 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
@@ -17,6 +17,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
 import java.util.List;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags method invocations for which all arguments are wrapped using
@@ -24,12 +25,11 @@ import java.util.List;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "MockitoStubbing",
     summary = "Don't unnecessarily use Mockito's `eq(...)`",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class MockitoStubbingCheck extends BugChecker implements MethodInvocationTreeMatcher {
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class MockitoStubbing extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> MOCKITO_EQ_METHOD =
       staticMethod().onClass("org.mockito.ArgumentMatchers").named("eq");
@@ -45,7 +45,7 @@ public final class MockitoStubbingCheck extends BugChecker implements MethodInvo
     for (ExpressionTree arg : arguments) {
       suggestedFix.replace(
           arg,
-          Util.treeToString(
+          SourceCode.treeToString(
               Iterables.getOnlyElement(((MethodInvocationTree) arg).getArguments()), state));
     }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/PrimitiveComparison.java

@@ -1,16 +1,17 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.PERFORMANCE;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.joining;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
@@ -30,6 +31,8 @@ import com.sun.tools.javac.tree.JCTree.JCMemberReference;
 import java.util.Comparator;
 import java.util.Optional;
 import java.util.function.Function;
+import java.util.stream.Stream;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags {@code Comparator#comparing*} invocations that can be replaced
@@ -37,18 +40,15 @@ import java.util.function.Function;
  */
 // XXX: Add more documentation. Explain how this is useful in the face of refactoring to more
 // specific types.
-// XXX: Change this checker's name?
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "PrimitiveComparison",
     summary =
         "Ensure invocations of `Comparator#comparing{,Double,Int,Long}` match the return type"
             + " of the provided function",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.PERFORMANCE)
-public final class PrimitiveComparisonCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+    linkType = NONE,
+    severity = WARNING,
+    tags = PERFORMANCE)
+public final class PrimitiveComparison extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> STATIC_COMPARISON_METHOD =
       anyOf(
@@ -77,23 +77,53 @@ public final class PrimitiveComparisonCheck extends BugChecker
     }
 
     return getPotentiallyBoxedReturnType(tree.getArguments().get(0))
-        .flatMap(cmpType -> tryFix(tree, state, cmpType, isStatic))
+        .flatMap(cmpType -> attemptMethodInvocationReplacement(tree, cmpType, isStatic, state))
         .map(fix -> describeMatch(tree, fix))
         .orElse(Description.NO_MATCH);
   }
 
-  private static Optional<Fix> tryFix(
-      MethodInvocationTree tree, VisitorState state, Type cmpType, boolean isStatic) {
+  private static Optional<Fix> attemptMethodInvocationReplacement(
+      MethodInvocationTree tree, Type cmpType, boolean isStatic, VisitorState state) {
     return Optional.ofNullable(ASTHelpers.getSymbol(tree))
         .map(methodSymbol -> methodSymbol.getSimpleName().toString())
         .flatMap(
             actualMethodName ->
-                Optional.of(getPreferredMethod(state, cmpType, isStatic))
+                Optional.of(getPreferredMethod(cmpType, isStatic, state))
                     .filter(not(actualMethodName::equals)))
+        .map(
+            preferredMethodName ->
+                prefixTypeArgumentsIfRelevant(preferredMethodName, tree, cmpType, state))
         .map(preferredMethodName -> suggestFix(tree, preferredMethodName, state));
   }
 
-  private static String getPreferredMethod(VisitorState state, Type cmpType, boolean isStatic) {
+  /**
+   * Prefixes the given method name with generic type parameters if it replaces a {@code
+   * Comparator#comparing{,Double,Long,Int}} method which also has generic type parameters.
+   *
+   * <p>Such type parameters are retained as they are likely required.
+   *
+   * <p>Note that any type parameter to {@code Comparator#thenComparing} is likely redundant, and in
+   * any case becomes obsolete once that method is replaced with {@code
+   * Comparator#thenComparing{Double,Long,Int}}. Conversion in the opposite direction does not
+   * require the introduction of a generic type parameter.
+   */
+  private static String prefixTypeArgumentsIfRelevant(
+      String preferredMethodName, MethodInvocationTree tree, Type cmpType, VisitorState state) {
+    if (tree.getTypeArguments().isEmpty() || preferredMethodName.startsWith("then")) {
+      return preferredMethodName;
+    }
+
+    String typeArguments =
+        Stream.concat(
+                Stream.of(SourceCode.treeToString(tree.getTypeArguments().get(0), state)),
+                Stream.of(cmpType.tsym.getSimpleName())
+                    .filter(u -> "comparing".equals(preferredMethodName)))
+            .collect(joining(", ", "<", ">"));
+
+    return typeArguments + preferredMethodName;
+  }
+
+  private static String getPreferredMethod(Type cmpType, boolean isStatic, VisitorState state) {
     Types types = state.getTypes();
     Symtab symtab = state.getSymtab();
 
@@ -128,9 +158,6 @@ public final class PrimitiveComparisonCheck extends BugChecker
     }
   }
 
-  // XXX: We drop explicitly specified generic type information. In case the number of type
-  // arguments before and after doesn't match, that's for the better. But if we e.g. replace
-  // `comparingLong` with `comparingInt`, then we should retain it.
   private static Fix suggestFix(
       MethodInvocationTree tree, String preferredMethodName, VisitorState state) {
     ExpressionTree expr = tree.getMethodSelect();
@@ -143,7 +170,7 @@ public final class PrimitiveComparisonCheck extends BugChecker
       case MEMBER_SELECT:
         MemberSelectTree ms = (MemberSelectTree) tree.getMethodSelect();
         return SuggestedFix.replace(
-            ms, Util.treeToString(ms.getExpression(), state) + '.' + preferredMethodName);
+            ms, SourceCode.treeToString(ms.getExpression(), state) + '.' + preferredMethodName);
       default:
         throw new VerifyException("Unexpected type of expression: " + expr.getKind());
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java

@@ -1,5 +1,8 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.allOf;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.isNonNullUsingDataflow;
@@ -12,9 +15,6 @@ import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 import com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -41,16 +41,17 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
 import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.MethodMatcherFactory;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} which flags redundant explicit string conversions. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "RedundantStringConversion",
     summary = "Avoid redundant string conversions when possible",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class RedundantStringConversionCheck extends BugChecker
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class RedundantStringConversion extends BugChecker
     implements BinaryTreeMatcher, CompoundAssignmentTreeMatcher, MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String FLAG_PREFIX = "RedundantStringConversion:";
@@ -157,17 +158,17 @@ public final class RedundantStringConversionCheck extends BugChecker
 
   private final Matcher<ExpressionTree> conversionMethodMatcher;
 
-  /** Instantiates the default {@link RedundantStringConversionCheck}. */
-  public RedundantStringConversionCheck() {
+  /** Instantiates the default {@link RedundantStringConversion}. */
+  public RedundantStringConversion() {
     this(ErrorProneFlags.empty());
   }
 
   /**
-   * Instantiates a customized {@link RedundantStringConversionCheck}.
+   * Instantiates a customized {@link RedundantStringConversion}.
    *
    * @param flags Any provided command line flags.
    */
-  public RedundantStringConversionCheck(ErrorProneFlags flags) {
+  public RedundantStringConversion(ErrorProneFlags flags) {
     conversionMethodMatcher = createConversionMethodMatcher(flags);
   }
 
@@ -326,7 +327,7 @@ public final class RedundantStringConversionCheck extends BugChecker
     return trySimplify(tree, state, filter)
         .map(
             replacement ->
-                SuggestedFix.builder().replace(tree, Util.treeToString(replacement, state)));
+                SuggestedFix.builder().replace(tree, SourceCode.treeToString(replacement, state)));
   }
 
   private Optional<ExpressionTree> trySimplify(
@@ -350,7 +351,7 @@ public final class RedundantStringConversionCheck extends BugChecker
       default:
         throw new IllegalStateException(
             "Cannot simplify method call with two or more arguments: "
-                + Util.treeToString(tree, state));
+                + SourceCode.treeToString(tree, state));
     }
   }
 
@@ -363,7 +364,7 @@ public final class RedundantStringConversionCheck extends BugChecker
     return Optional.of(methodInvocation.getMethodSelect())
         .filter(methodSelect -> methodSelect.getKind() == Kind.MEMBER_SELECT)
         .map(methodSelect -> ((MemberSelectTree) methodSelect).getExpression())
-        .filter(expr -> !"super".equals(Util.treeToString(expr, state)));
+        .filter(expr -> !"super".equals(SourceCode.treeToString(expr, state)));
   }
 
   private static Optional<ExpressionTree> trySimplifyUnaryMethod(

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RefasterAnyOfUsage.java

@@ -1,12 +1,12 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
@@ -16,6 +16,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.refaster.Refaster;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags unnecessary {@link Refaster#anyOf(Object[])} usages.
@@ -25,13 +26,11 @@ import com.sun.source.tree.MethodInvocationTree;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "RefasterAnyOfUsage",
     summary = "`Refaster#anyOf` should be passed at least two parameters",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class RefasterAnyOfUsageCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class RefasterAnyOfUsage extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> REFASTER_ANY_OF =
       staticMethod().onClass(Refaster.class.getName()).named("anyOf");
@@ -46,7 +45,8 @@ public final class RefasterAnyOfUsageCheck extends BugChecker
         case 1:
           return describeMatch(
               tree,
-              SuggestedFix.replace(tree, Util.treeToString(tree.getArguments().get(0), state)));
+              SuggestedFix.replace(
+                  tree, SourceCode.treeToString(tree.getArguments().get(0), state)));
         default:
           /* Handled below. */
       }

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestMappingAnnotation.java

@@ -1,20 +1,19 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.ALL;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
 import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.isSameType;
-import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
 import static com.google.errorprone.matchers.Matchers.isType;
 import static com.google.errorprone.matchers.Matchers.methodHasParameters;
 import static com.google.errorprone.matchers.Matchers.not;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
@@ -31,12 +30,11 @@ import com.sun.source.tree.Tree;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "RequestMappingAnnotation",
     summary = "Make sure all `@RequestMapping` method parameters are annotated",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.LIKELY_ERROR)
-public final class RequestMappingAnnotationCheck extends BugChecker implements MethodTreeMatcher {
+    linkType = NONE,
+    severity = WARNING,
+    tags = LIKELY_ERROR)
+public final class RequestMappingAnnotation extends BugChecker implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String ANN_PACKAGE_PREFIX = "org.springframework.web.bind.annotation.";
   // XXX: Generalize this logic to fully support Spring meta-annotations, then update the class
@@ -51,8 +49,11 @@ public final class RequestMappingAnnotationCheck extends BugChecker implements M
               isType(ANN_PACKAGE_PREFIX + "PostMapping"),
               isType(ANN_PACKAGE_PREFIX + "PutMapping"),
               isType(ANN_PACKAGE_PREFIX + "RequestMapping")));
-  // XXX: Add other parameters as necessary. See
-  // https://docs.spring.io/spring/docs/current/spring-framework-reference/web.html#mvc-ann-arguments.
+  // XXX: Add other parameters as necessary. Also consider whether it makes sense to have WebMVC-
+  // and WebFlux-specific logic. See
+  // https://docs.spring.io/spring-framework/docs/current/reference/html/web.html#mvc-ann-arguments
+  // and
+  // https://docs.spring.io/spring-framework/docs/current/reference/html/web-reactive.html#webflux-ann-arguments.
   private static final Matcher<MethodTree> LACKS_PARAMETER_ANNOTATION =
       not(
           methodHasParameters(
@@ -66,10 +67,17 @@ public final class RequestMappingAnnotationCheck extends BugChecker implements M
                           isType(ANN_PACKAGE_PREFIX + "RequestHeader"),
                           isType(ANN_PACKAGE_PREFIX + "RequestParam"))),
                   isSameType("java.io.InputStream"),
+                  isSameType("java.time.ZoneId"),
+                  isSameType("java.util.Locale"),
+                  isSameType("java.util.TimeZone"),
                   isSameType("javax.servlet.http.HttpServletRequest"),
                   isSameType("javax.servlet.http.HttpServletResponse"),
                   isSameType("org.springframework.http.HttpMethod"),
-                  isSubtypeOf("org.springframework.web.context.request.WebRequest"))));
+                  isSameType("org.springframework.web.context.request.NativeWebRequest"),
+                  isSameType("org.springframework.web.context.request.WebRequest"),
+                  isSameType("org.springframework.web.server.ServerWebExchange"),
+                  isSameType("org.springframework.web.util.UriBuilder"),
+                  isSameType("org.springframework.web.util.UriComponentsBuilder"))));
 
   @Override
   public Description matchMethod(MethodTree tree, VisitorState state) {

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamType.java

@@ -0,0 +1,44 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.annotations;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
+import static com.google.errorprone.matchers.Matchers.isType;
+
+import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableMap;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.VariableTreeMatcher;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.VariableTree;
+
+/** A {@link BugChecker} which flags {@code @RequestParam} parameters with an unsupported type. */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "`@RequestParam` does not support `ImmutableCollection` and `ImmutableMap` subtypes",
+    linkType = NONE,
+    severity = ERROR,
+    tags = LIKELY_ERROR)
+public final class RequestParamType extends BugChecker implements VariableTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<VariableTree> HAS_UNSUPPORTED_REQUEST_PARAM =
+      allOf(
+          annotations(AT_LEAST_ONE, isType("org.springframework.web.bind.annotation.RequestParam")),
+          anyOf(isSubtypeOf(ImmutableCollection.class), isSubtypeOf(ImmutableMap.class)));
+
+  @Override
+  public Description matchVariable(VariableTree tree, VisitorState state) {
+    return HAS_UNSUPPORTED_REQUEST_PARAM.matches(tree, state)
+        ? describeMatch(tree)
+        : Description.NO_MATCH;
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ScheduledTransactionTrace.java

@@ -0,0 +1,87 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Matchers.annotations;
+import static com.google.errorprone.matchers.Matchers.hasAnnotation;
+import static com.google.errorprone.matchers.Matchers.isType;
+
+import com.google.auto.common.AnnotationMirrors;
+import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.Iterables;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.matchers.MultiMatcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.AnnotationTree;
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.Tree;
+
+/**
+ * A {@link BugChecker} which flags methods with Spring's {@code @Scheduled} annotation that lack
+ * New Relic Agent's {@code @Trace(dispatcher = true)}.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Scheduled operation must start a new New Relic transaction",
+    linkType = NONE,
+    severity = ERROR,
+    tags = LIKELY_ERROR)
+public final class ScheduledTransactionTrace extends BugChecker implements MethodTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final String TRACE_ANNOTATION_FQCN = "com.newrelic.api.agent.Trace";
+  private static final Matcher<Tree> IS_SCHEDULED =
+      hasAnnotation("org.springframework.scheduling.annotation.Scheduled");
+  private static final MultiMatcher<Tree, AnnotationTree> TRACE_ANNOTATION =
+      annotations(AT_LEAST_ONE, isType(TRACE_ANNOTATION_FQCN));
+
+  @Override
+  public Description matchMethod(MethodTree tree, VisitorState state) {
+    if (!IS_SCHEDULED.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    ImmutableList<AnnotationTree> traceAnnotations =
+        TRACE_ANNOTATION.multiMatchResult(tree, state).matchingNodes();
+    if (traceAnnotations.isEmpty()) {
+      /* This method completely lacks the `@Trace` annotation; add it. */
+      return describeMatch(
+          tree,
+          SuggestedFix.builder()
+              .addImport(TRACE_ANNOTATION_FQCN)
+              .prefixWith(tree, "@Trace(dispatcher = true)")
+              .build());
+    }
+
+    AnnotationTree traceAnnotation = Iterables.getOnlyElement(traceAnnotations);
+    if (isCorrectAnnotation(traceAnnotation)) {
+      return Description.NO_MATCH;
+    }
+
+    /*
+     * The `@Trace` annotation is present but does not specify `dispatcher = true`. Add or update
+     * the `dispatcher` annotation element.
+     */
+    return describeMatch(
+        traceAnnotation,
+        SuggestedFixes.updateAnnotationArgumentValues(
+                traceAnnotation, state, "dispatcher", ImmutableList.of("true"))
+            .build());
+  }
+
+  private static boolean isCorrectAnnotation(AnnotationTree traceAnnotation) {
+    return Boolean.TRUE.equals(
+        AnnotationMirrors.getAnnotationValue(
+                ASTHelpers.getAnnotationMirror(traceAnnotation), "dispatcher")
+            .getValue());
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/Slf4jLogStatement.java

@@ -1,15 +1,15 @@
 package tech.picnic.errorprone.bugpatterns;
 
 import static com.google.common.base.Verify.verify;
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
 import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
@@ -22,6 +22,7 @@ import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.Tree.Kind;
 import java.util.List;
 import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} which flags SLF4J usages that are likely to be in error. */
 // XXX: The special-casing of Throwable applies only to SLF4J 1.6.0+; see
@@ -31,13 +32,11 @@ import java.util.Optional;
 // preconditions, ...
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "Slf4jLogStatement",
     summary = "Make sure SLF4J log statements contain proper placeholders with matching arguments",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.LIKELY_ERROR)
-public final class Slf4jLogStatementCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+    linkType = NONE,
+    severity = WARNING,
+    tags = LIKELY_ERROR)
+public final class Slf4jLogStatement extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> MARKER = isSubtypeOf("org.slf4j.Marker");
   private static final Matcher<ExpressionTree> THROWABLE = isSubtypeOf(Throwable.class);
@@ -114,7 +113,7 @@ public final class Slf4jLogStatementCheck extends BugChecker
        * replaced at this usage site.
        */
       description.addFix(
-          SuggestedFix.replace(tree, Util.treeToString(tree, state).replace("%s", "{}")));
+          SuggestedFix.replace(tree, SourceCode.treeToString(tree, state).replace("%s", "{}")));
     }
 
     return false;

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/SpringMvcAnnotation.java

@@ -1,6 +1,9 @@
 package tech.picnic.errorprone.bugpatterns;
 
 import static com.google.common.base.Verify.verify;
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static java.util.function.Predicate.not;
 import static java.util.stream.Collectors.joining;
 
@@ -9,9 +12,6 @@ import com.google.common.base.VerifyException;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.AnnotationTreeMatcher;
@@ -25,6 +25,8 @@ import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.NewArrayTree;
 import com.sun.source.tree.Tree.Kind;
 import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags {@code @RequestMapping} annotations that can be written more
@@ -32,13 +34,12 @@ import java.util.Optional;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "SpringMvcAnnotation",
     summary =
         "Prefer the conciseness of `@{Get,Put,Post,Delete,Patch}Mapping` over `@RequestMapping`",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class SpringMvcAnnotationCheck extends BugChecker implements AnnotationTreeMatcher {
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class SpringMvcAnnotation extends BugChecker implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String ANN_PACKAGE_PREFIX = "org.springframework.web.bind.annotation.";
   private static final AnnotationAttributeMatcher ARGUMENT_SELECTOR =
@@ -92,7 +93,7 @@ public final class SpringMvcAnnotationCheck extends BugChecker implements Annota
   private static String extractMethod(ExpressionTree expr, VisitorState state) {
     switch (expr.getKind()) {
       case IDENTIFIER:
-        return Util.treeToString(expr, state);
+        return SourceCode.treeToString(expr, state);
       case MEMBER_SELECT:
         return ((MemberSelectTree) expr).getIdentifier().toString();
       default:
@@ -105,7 +106,7 @@ public final class SpringMvcAnnotationCheck extends BugChecker implements Annota
     String newArguments =
         tree.getArguments().stream()
             .filter(not(argToRemove::equals))
-            .map(arg -> Util.treeToString(arg, state))
+            .map(arg -> SourceCode.treeToString(arg, state))
             .collect(joining(", "));
 
     return SuggestedFix.builder()

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StaticImport.java

@@ -1,5 +1,8 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static java.util.Objects.requireNonNull;
 
 import com.google.auto.service.AutoService;
@@ -7,9 +10,6 @@ import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSetMultimap;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MemberSelectTreeMatcher;
@@ -19,14 +19,18 @@ import com.google.errorprone.fixes.Fix;
 import com.google.errorprone.fixes.SuggestedFix;
 import com.google.errorprone.fixes.SuggestedFixes;
 import com.google.errorprone.matchers.Description;
+import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.Tree;
+import com.sun.tools.javac.code.Type;
 import java.util.Optional;
 
-/** A {@link BugChecker} which flags methods that can and should be statically imported. */
+/**
+ * A {@link BugChecker} which flags methods and constants that can and should be statically
+ * imported.
+ */
 // XXX: Tricky cases:
-// - `org.springframework.http.MediaType` (do except for `ALL`?)
 // - `org.springframework.http.HttpStatus` (not always an improvement, and `valueOf` must
 //    certainly be excluded)
 // - `com.google.common.collect.Tables`
@@ -41,21 +45,28 @@ import java.util.Optional;
 // - Likely any of `*.{ZERO, ONE, MIX, MAX, MIN_VALUE, MAX_VALUE}`.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "StaticImport",
-    summary = "Method should be statically imported",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.SIMPLIFICATION)
-public final class StaticImportCheck extends BugChecker implements MemberSelectTreeMatcher {
+    summary = "Identifier should be statically imported",
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class StaticImport extends BugChecker implements MemberSelectTreeMatcher {
   private static final long serialVersionUID = 1L;
 
+  /**
+   * Types whose members should be statically imported, unless exempted by {@link
+   * #STATIC_IMPORT_EXEMPTED_MEMBERS} or {@link #STATIC_IMPORT_EXEMPTED_IDENTIFIERS}.
+   */
   @VisibleForTesting
-  static final ImmutableSet<String> STATIC_IMPORT_CANDIDATE_CLASSES =
+  static final ImmutableSet<String> STATIC_IMPORT_CANDIDATE_TYPES =
       ImmutableSet.of(
           "com.google.common.base.Preconditions",
           "com.google.common.base.Predicates",
           "com.google.common.base.Verify",
           "com.google.common.collect.MoreCollectors",
+          "com.google.errorprone.BugPattern.LinkType",
+          "com.google.errorprone.BugPattern.SeverityLevel",
+          "com.google.errorprone.BugPattern.StandardTags",
+          "com.google.errorprone.refaster.ImportPolicy",
           "com.mongodb.client.model.Accumulators",
           "com.mongodb.client.model.Aggregates",
           "com.mongodb.client.model.Filters",
@@ -64,8 +75,10 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
           "com.mongodb.client.model.Sorts",
           "com.mongodb.client.model.Updates",
           "java.nio.charset.StandardCharsets",
+          "java.util.Collections",
           "java.util.Comparator",
           "java.util.Map.Entry",
+          "java.util.regex.Pattern",
           "java.util.stream.Collectors",
           "org.assertj.core.api.Assertions",
           "org.assertj.core.api.InstanceOfAssertFactories",
@@ -80,14 +93,17 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
           "org.mockito.Answers",
           "org.mockito.ArgumentMatchers",
           "org.mockito.Mockito",
+          "org.springframework.boot.test.context.SpringBootTest.WebEnvironment",
           "org.springframework.format.annotation.DateTimeFormat.ISO",
           "org.springframework.http.HttpHeaders",
           "org.springframework.http.HttpMethod",
+          "org.springframework.http.MediaType",
           "org.testng.Assert",
           "reactor.function.TupleUtils");
 
+  /** Type members that should be statically imported. */
   @VisibleForTesting
-  static final ImmutableSetMultimap<String, String> STATIC_IMPORT_CANDIDATE_METHODS =
+  static final ImmutableSetMultimap<String, String> STATIC_IMPORT_CANDIDATE_MEMBERS =
       ImmutableSetMultimap.<String, String>builder()
           .putAll(
               "com.google.common.collect.ImmutableListMultimap",
@@ -108,8 +124,10 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
           .put("com.google.common.collect.ImmutableTable", "toImmutableTable")
           .put("com.google.common.collect.Sets", "toImmutableEnumSet")
           .put("com.google.common.base.Functions", "identity")
+          .put("java.time.ZoneOffset", "UTC")
           .put("java.util.function.Function", "identity")
           .put("java.util.function.Predicate", "not")
+          .put("java.util.UUID", "randomUUID")
           .put("org.junit.jupiter.params.provider.Arguments", "arguments")
           .putAll(
               "java.util.Objects",
@@ -122,9 +140,57 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
           .putAll("com.google.common.collect.Comparators", "emptiesFirst", "emptiesLast")
           .build();
 
+  /**
+   * Type members that should never be statically imported.
+   *
+   * <p>Identifiers listed by {@link #STATIC_IMPORT_EXEMPTED_IDENTIFIERS} should be omitted from
+   * this collection.
+   */
+  // XXX: Perhaps the set of exempted `java.util.Collections` methods is too strict. For now any
+  // method name that could be considered "too vague" or could conceivably mean something else in a
+  // specific context is left out.
+  @VisibleForTesting
+  static final ImmutableSetMultimap<String, String> STATIC_IMPORT_EXEMPTED_MEMBERS =
+      ImmutableSetMultimap.<String, String>builder()
+          .put("com.mongodb.client.model.Filters", "empty")
+          .putAll(
+              "java.util.Collections",
+              "addAll",
+              "copy",
+              "fill",
+              "list",
+              "max",
+              "min",
+              "nCopies",
+              "rotate",
+              "sort",
+              "swap")
+          .putAll("java.util.regex.Pattern", "compile", "matches", "quote")
+          .put("org.springframework.http.MediaType", "ALL")
+          .build();
+
+  /**
+   * Identifiers that should never be statically imported.
+   *
+   * <p>This should be a superset of the identifiers flagged by {@link
+   * com.google.errorprone.bugpatterns.BadImport}.
+   */
+  @VisibleForTesting
+  static final ImmutableSet<String> STATIC_IMPORT_EXEMPTED_IDENTIFIERS =
+      ImmutableSet.of(
+          "builder",
+          "create",
+          "copyOf",
+          "from",
+          "getDefaultInstance",
+          "INSTANCE",
+          "newBuilder",
+          "of",
+          "valueOf");
+
   @Override
   public Description matchMemberSelect(MemberSelectTree tree, VisitorState state) {
-    if (!isCandidate(state)) {
+    if (!isCandidateContext(state) || !isCandidate(tree)) {
       return Description.NO_MATCH;
     }
 
@@ -139,7 +205,7 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
         .orElse(Description.NO_MATCH);
   }
 
-  private static boolean isCandidate(VisitorState state) {
+  private static boolean isCandidateContext(VisitorState state) {
     Tree parentTree =
         requireNonNull(state.getPath().getParentPath(), "MemberSelectTree lacks enclosing node")
             .getLeaf();
@@ -154,6 +220,17 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
     }
   }
 
+  private static boolean isCandidate(MemberSelectTree tree) {
+    String identifier = tree.getIdentifier().toString();
+    if (STATIC_IMPORT_EXEMPTED_IDENTIFIERS.contains(identifier)) {
+      return false;
+    }
+
+    Type type = ASTHelpers.getType(tree.getExpression());
+    return type != null
+        && !STATIC_IMPORT_EXEMPTED_MEMBERS.containsEntry(type.toString(), identifier);
+  }
+
   private static Optional<String> getCandidateSimpleName(StaticImportInfo importInfo) {
     String canonicalName = importInfo.canonicalName();
     return importInfo
@@ -161,8 +238,8 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
         .toJavaUtil()
         .filter(
             name ->
-                STATIC_IMPORT_CANDIDATE_CLASSES.contains(canonicalName)
-                    || STATIC_IMPORT_CANDIDATE_METHODS.containsEntry(canonicalName, name));
+                STATIC_IMPORT_CANDIDATE_TYPES.contains(canonicalName)
+                    || STATIC_IMPORT_CANDIDATE_MEMBERS.containsEntry(canonicalName, name));
   }
 
   private static Optional<Fix> tryStaticImport(

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StringIsEmptyCheck.java

@@ -1,42 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.errorprone.BugPattern.LinkType;
-import static com.google.errorprone.BugPattern.SeverityLevel;
-import static com.google.errorprone.BugPattern.StandardTags;
-import static com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
-import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
-import static com.sun.source.tree.Tree.Kind;
-
-import com.google.auto.service.AutoService;
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.bugpatterns.BugChecker;
-import com.google.errorprone.fixes.SuggestedFix;
-import com.google.errorprone.matchers.Description;
-import com.google.errorprone.matchers.Matcher;
-import com.google.errorprone.util.ASTHelpers;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.LiteralTree;
-import com.sun.source.tree.MethodInvocationTree;
-
-@AutoService(BugChecker.class)
-@BugPattern(
-    name = "StringIsEmpty",
-    summary = "Prefer `String#isEmpty` over `String#equals`",
-    severity = SeverityLevel.SUGGESTION,
-    tags = StandardTags.STYLE)
-public final class StringIsEmptyCheck extends BugChecker implements MethodInvocationTreeMatcher {
-  private static final Matcher<ExpressionTree> STRING_EQUALS_INVOCATION =
-      instanceMethod().onDescendantOf("java.lang.String").named("equals");
-
-  @Override
-  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    if (STRING_EQUALS_INVOCATION.matches(tree, state)
-        && tree.getArguments().get(0).getKind() == Kind.STRING_LITERAL
-        && ((LiteralTree) tree.getArguments().get(0)).getValue().equals("")) {
-      return describeMatch(
-          tree, SuggestedFix.replace(tree, ASTHelpers.getReceiver(tree) + ".isEmpty()"));
-    }
-    return Description.NO_MATCH;
-  }
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/TimeZoneUsage.java

@@ -1,5 +1,8 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
 import static com.google.errorprone.matchers.Matchers.allOf;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.enclosingClass;
@@ -10,9 +13,6 @@ import static com.google.errorprone.matchers.Matchers.staticMethod;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
-import com.google.errorprone.BugPattern.LinkType;
-import com.google.errorprone.BugPattern.SeverityLevel;
-import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
@@ -29,13 +29,12 @@ import java.time.LocalTime;
 /** A {@link BugChecker} which flags illegal time-zone related operations. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "TimeZoneUsage",
     summary =
         "Derive the current time from an existing `Clock` Spring bean, and don't rely on a `Clock`'s time zone",
-    linkType = LinkType.NONE,
-    severity = SeverityLevel.WARNING,
-    tags = StandardTags.FRAGILE_CODE)
-public final class TimeZoneUsageCheck extends BugChecker implements MethodInvocationTreeMatcher {
+    linkType = NONE,
+    severity = WARNING,
+    tags = FRAGILE_CODE)
+public final class TimeZoneUsage extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> BANNED_TIME_METHOD =
       anyOf(
@@ -59,7 +58,7 @@ public final class TimeZoneUsageCheck extends BugChecker implements MethodInvoca
                   LocalDateTime.class.getName(),
                   LocalTime.class.getName())
               .named("now"),
-          staticMethod().onClassAny(Instant.class.getName()).named("now").withParameters());
+          staticMethod().onClassAny(Instant.class.getName()).named("now").withNoParameters());
 
   @Override
   public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/AnnotationAttributeMatcher.java

@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.bugpatterns;
+package tech.picnic.errorprone.bugpatterns.util;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.HashMultimap;
@@ -28,7 +28,7 @@ import java.util.stream.Stream;
  * <p>This class allows one to define a whitelist or blacklist of annotations or their attributes.
  * Annotations are identified by their fully qualified name.
  */
-final class AnnotationAttributeMatcher implements Serializable {
+public final class AnnotationAttributeMatcher implements Serializable {
   private static final long serialVersionUID = 1L;
 
   private final boolean complement;
@@ -59,7 +59,7 @@ final class AnnotationAttributeMatcher implements Serializable {
    * @param exclusions The listed annotations or annotation attributes are not matched.
    * @return A non-{@code null} {@link AnnotationAttributeMatcher}.
    */
-  static AnnotationAttributeMatcher create(
+  public static AnnotationAttributeMatcher create(
       Optional<? extends List<String>> inclusions, Iterable<String> exclusions) {
     Set<String> includedWholeTypes = new HashSet<>();
     Set<String> excludedWholeTypes = new HashSet<>();
@@ -97,7 +97,13 @@ final class AnnotationAttributeMatcher implements Serializable {
     }
   }
 
-  Stream<? extends ExpressionTree> extractMatchingArguments(AnnotationTree tree) {
+  /**
+   * Returns the subset of arguments of the given {@link AnnotationTree} matched by this instance.
+   *
+   * @param tree The annotation AST node to be inspected.
+   * @return Any matching annotation arguments.
+   */
+  public Stream<? extends ExpressionTree> extractMatchingArguments(AnnotationTree tree) {
     Type type = ASTHelpers.getType(tree.getAnnotationType());
     if (type == null) {
       return Stream.empty();

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/JavaKeywords.java

@@ -0,0 +1,129 @@
+package tech.picnic.errorprone.bugpatterns.util;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+
+/** Utility class that can be used to identify reserved keywords of the Java language. */
+public final class JavaKeywords {
+  /**
+   * List of all reserved keywords in the Java language.
+   *
+   * @see <a href="https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.9">JDK 17 JLS
+   *     section 3.9: Keywords</a>
+   */
+  private static final ImmutableSet<String> RESERVED_KEYWORDS =
+      ImmutableSet.of(
+          "_",
+          "abstract",
+          "assert",
+          "boolean",
+          "break",
+          "byte",
+          "case",
+          "catch",
+          "char",
+          "class",
+          "const",
+          "continue",
+          "default",
+          "do",
+          "double",
+          "else",
+          "enum",
+          "extends",
+          "final",
+          "finally",
+          "float",
+          "for",
+          "goto",
+          "if",
+          "implements",
+          "import",
+          "instanceof",
+          "int",
+          "interface",
+          "long",
+          "native",
+          "new",
+          "package",
+          "private",
+          "protected",
+          "public",
+          "return",
+          "short",
+          "static",
+          "strictfp",
+          "super",
+          "switch",
+          "synchronized",
+          "this",
+          "throw",
+          "throws",
+          "transient",
+          "try",
+          "void",
+          "volatile",
+          "while");
+
+  /**
+   * List of all contextual keywords in the Java language.
+   *
+   * @see <a href="https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.9">JDK 17 JLS
+   *     section 3.9: Keywords</a>
+   */
+  private static final ImmutableSet<String> CONTEXTUAL_KEYWORDS =
+      ImmutableSet.of(
+          "exports",
+          "module",
+          "non-sealed",
+          "open",
+          "opens",
+          "permits",
+          "provides",
+          "record",
+          "requires",
+          "sealed",
+          "to",
+          "transitive",
+          "uses",
+          "var",
+          "with",
+          "yield");
+
+  /** List of all keywords in the Java language. */
+  private static final ImmutableSet<String> ALL_KEYWORDS =
+      Sets.union(RESERVED_KEYWORDS, CONTEXTUAL_KEYWORDS).immutableCopy();
+
+  private JavaKeywords() {}
+
+  /**
+   * Tells whether the given string is a reserved keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a reserved keyword in the Java language.
+   */
+  public static boolean isReservedKeyword(String str) {
+    return RESERVED_KEYWORDS.contains(str);
+  }
+
+  /**
+   * Tells whether the given string is a contextual keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a contextual keyword in the Java language.
+   */
+  public static boolean isContextualKeyword(String str) {
+    return CONTEXTUAL_KEYWORDS.contains(str);
+  }
+
+  /**
+   * Tells whether the given string is a reserved or contextual keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a reserved or contextual keyword in the Java
+   *     language.
+   */
+  public static boolean isKeyword(String str) {
+    return ALL_KEYWORDS.contains(str);
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MethodMatcherFactory.java

@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.bugpatterns;
+package tech.picnic.errorprone.bugpatterns.util;
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
@@ -15,13 +15,20 @@ import java.util.regex.Pattern;
 /** A method invocation expression {@link Matcher} factory. */
 // XXX: Document better. The expressions accepted here could also be defined using `MethodMatchers`.
 // So explain why this class is still useful.
-final class MethodMatcherFactory {
+public final class MethodMatcherFactory {
   private static final Splitter ARGUMENT_TYPE_SPLITTER =
       Splitter.on(',').trimResults().omitEmptyStrings();
   private static final Pattern METHOD_SIGNATURE =
       Pattern.compile("([^\\s#(,)]+)#([^\\s#(,)]+)\\(((?:[^\\s#(,)]+(?:,[^\\s#(,)]+)*)?)\\)");
 
-  Matcher<ExpressionTree> create(Collection<String> signatures) {
+  /**
+   * Creates a {@link Matcher} of methods with any of the given signatures.
+   *
+   * @param signatures The method signatures of interest.
+   * @return A new {@link Matcher} which accepts invocation expressions of any method identified by
+   *     the given signatures.
+   */
+  public Matcher<ExpressionTree> create(Collection<String> signatures) {
     return anyOf(
         signatures.stream()
             .map(MethodMatcherFactory::createMethodMatcher)

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/SourceCode.java

@@ -1,19 +1,26 @@
-package tech.picnic.errorprone.bugpatterns;
+package tech.picnic.errorprone.bugpatterns.util;
 
 import com.google.errorprone.VisitorState;
 import com.sun.source.tree.Tree;
 
+/**
+ * A collection of Error Prone utility methods for dealing with the source code representation of
+ * AST nodes.
+ */
 // XXX: Can we locate this code in a better place? Maybe contribute it upstream?
-final class Util {
-  private Util() {}
+public final class SourceCode {
+  private SourceCode() {}
 
   /**
    * Returns a string representation of the given {@link Tree}, preferring the original source code
    * (if available) over its prettified representation.
    *
+   * @param tree The AST node of interest.
+   * @param state A {@link VisitorState} describing the context in which the given {@link Tree} is
+   *     found.
    * @return A non-{@code null} string.
    */
-  static String treeToString(Tree tree, VisitorState state) {
+  public static String treeToString(Tree tree, VisitorState state) {
     String src = state.getSourceForNode(tree);
     return src != null ? src : tree.toString();
   }

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/package-info.java

@@ -0,0 +1,4 @@
+/** Auxiliary utilities for use by Error Prone checks. */
+@com.google.errorprone.annotations.CheckReturnValue
+@javax.annotation.ParametersAreNonnullByDefault
+package tech.picnic.errorprone.bugpatterns.util;

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJBigDecimalTemplates.java

@@ -8,13 +8,22 @@ import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import java.math.BigDecimal;
 import org.assertj.core.api.AbstractBigDecimalAssert;
+import org.assertj.core.api.BigDecimalAssert;
 
-// XXX: If we add a rule which drops unnecessary `L` suffixes from literal longs, then the `0L`/`1L`
-// cases below can go.
+/**
+ * Refaster templates related to AssertJ assertions over {@link BigDecimal}s.
+ *
+ * <p>Note that, contrary to collections of Refaster templates for other {@link
+ * org.assertj.core.api.NumberAssert} subtypes, these templates do not rewrite to/from {@link
+ * BigDecimalAssert#isEqualTo(Object)} and {@link BigDecimalAssert#isNotEqualTo(Object)}. This is
+ * because {@link BigDecimal#equals(Object)} considers not only the numeric value of compared
+ * instances, but also their scale. As a result various seemingly straightforward transformations
+ * would actually subtly change the assertion's semantics.
+ */
 final class AssertJBigDecimalTemplates {
   private AssertJBigDecimalTemplates() {}
 
-  static final class AbstractBigDecimalAssertIsEqualTo {
+  static final class AbstractBigDecimalAssertIsEqualByComparingTo {
     @BeforeTemplate
     AbstractBigDecimalAssert<?> before(AbstractBigDecimalAssert<?> bigDecimalAssert, BigDecimal n) {
       return Refaster.anyOf(
@@ -24,11 +33,11 @@ final class AssertJBigDecimalTemplates {
 
     @AfterTemplate
     AbstractBigDecimalAssert<?> after(AbstractBigDecimalAssert<?> bigDecimalAssert, BigDecimal n) {
-      return bigDecimalAssert.isEqualTo(n);
+      return bigDecimalAssert.isEqualByComparingTo(n);
     }
   }
 
-  static final class AbstractBigDecimalAssertIsNotEqualTo {
+  static final class AbstractBigDecimalAssertIsNotEqualByComparingTo {
     @BeforeTemplate
     AbstractBigDecimalAssert<?> before(AbstractBigDecimalAssert<?> bigDecimalAssert, BigDecimal n) {
       return Refaster.anyOf(
@@ -38,52 +47,7 @@ final class AssertJBigDecimalTemplates {
 
     @AfterTemplate
     AbstractBigDecimalAssert<?> after(AbstractBigDecimalAssert<?> bigDecimalAssert, BigDecimal n) {
-      return bigDecimalAssert.isNotEqualTo(n);
-    }
-  }
-
-  static final class AbstractBigDecimalAssertIsZero {
-    @BeforeTemplate
-    AbstractBigDecimalAssert<?> before(AbstractBigDecimalAssert<?> bigDecimalAssert) {
-      return Refaster.anyOf(
-          bigDecimalAssert.isZero(),
-          bigDecimalAssert.isEqualTo(0L),
-          bigDecimalAssert.isEqualTo(BigDecimal.ZERO));
-    }
-
-    @AfterTemplate
-    AbstractBigDecimalAssert<?> after(AbstractBigDecimalAssert<?> bigDecimalAssert) {
-      return bigDecimalAssert.isEqualTo(0);
-    }
-  }
-
-  static final class AbstractBigDecimalAssertIsNotZero {
-    @BeforeTemplate
-    AbstractBigDecimalAssert<?> before(AbstractBigDecimalAssert<?> bigDecimalAssert) {
-      return Refaster.anyOf(
-          bigDecimalAssert.isNotZero(),
-          bigDecimalAssert.isNotEqualTo(0L),
-          bigDecimalAssert.isNotEqualTo(BigDecimal.ZERO));
-    }
-
-    @AfterTemplate
-    AbstractBigDecimalAssert<?> after(AbstractBigDecimalAssert<?> bigDecimalAssert) {
-      return bigDecimalAssert.isNotEqualTo(0);
-    }
-  }
-
-  static final class AbstractBigDecimalAssertIsOne {
-    @BeforeTemplate
-    AbstractBigDecimalAssert<?> before(AbstractBigDecimalAssert<?> bigDecimalAssert) {
-      return Refaster.anyOf(
-          bigDecimalAssert.isOne(),
-          bigDecimalAssert.isEqualTo(1L),
-          bigDecimalAssert.isEqualTo(BigDecimal.ONE));
-    }
-
-    @AfterTemplate
-    AbstractBigDecimalAssert<?> after(AbstractBigDecimalAssert<?> bigDecimalAssert) {
-      return bigDecimalAssert.isEqualTo(1);
+      return bigDecimalAssert.isNotEqualByComparingTo(n);
     }
   }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJBooleanTemplates.java

@@ -1,8 +1,8 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -59,7 +59,7 @@ final class AssertJBooleanTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractBooleanAssert<?> after(boolean b) {
       return assertThat(b).isTrue();
     }
@@ -88,7 +88,7 @@ final class AssertJBooleanTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractBooleanAssert<?> after(boolean b) {
       return assertThat(b).isFalse();
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJByteTemplates.java

@@ -15,11 +15,7 @@ final class AssertJByteTemplates {
     @BeforeTemplate
     AbstractByteAssert<?> before(AbstractByteAssert<?> byteAssert, byte n) {
       return Refaster.anyOf(
-          byteAssert.isCloseTo(n, offset((byte) 0)),
-          byteAssert.isCloseTo(Byte.valueOf(n), offset((byte) 0)),
-          byteAssert.isCloseTo(n, withPercentage(0)),
-          byteAssert.isCloseTo(Byte.valueOf(n), withPercentage(0)),
-          byteAssert.isEqualTo(Byte.valueOf(n)));
+          byteAssert.isCloseTo(n, offset((byte) 0)), byteAssert.isCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate
@@ -33,10 +29,7 @@ final class AssertJByteTemplates {
     AbstractByteAssert<?> before(AbstractByteAssert<?> byteAssert, byte n) {
       return Refaster.anyOf(
           byteAssert.isNotCloseTo(n, offset((byte) 0)),
-          byteAssert.isNotCloseTo(Byte.valueOf(n), offset((byte) 0)),
-          byteAssert.isNotCloseTo(n, withPercentage(0)),
-          byteAssert.isNotCloseTo(Byte.valueOf(n), withPercentage(0)),
-          byteAssert.isNotEqualTo(Byte.valueOf(n)));
+          byteAssert.isNotCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJCharSequenceTemplates.java

@@ -1,8 +1,8 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -21,7 +21,7 @@ final class AssertJCharSequenceTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(CharSequence charSequence) {
       assertThat(charSequence).isEmpty();
     }
@@ -36,7 +36,7 @@ final class AssertJCharSequenceTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractAssert<?, ?> after(CharSequence charSequence) {
       return assertThat(charSequence).isNotEmpty();
     }
@@ -49,7 +49,7 @@ final class AssertJCharSequenceTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractAssert<?, ?> after(CharSequence charSequence, int length) {
       return assertThat(charSequence).hasSize(length);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJDoubleTemplates.java

@@ -36,11 +36,7 @@ final class AssertJDoubleTemplates {
     @BeforeTemplate
     AbstractDoubleAssert<?> before(AbstractDoubleAssert<?> doubleAssert, double n) {
       return Refaster.anyOf(
-          doubleAssert.isCloseTo(n, offset(0.0)),
-          doubleAssert.isCloseTo(Double.valueOf(n), offset(0.0)),
-          doubleAssert.isCloseTo(n, withPercentage(0.0)),
-          doubleAssert.isCloseTo(Double.valueOf(n), withPercentage(0.0)),
-          doubleAssert.isEqualTo(Double.valueOf(n)));
+          doubleAssert.isCloseTo(n, offset(0.0)), doubleAssert.isCloseTo(n, withPercentage(0.0)));
     }
 
     @AfterTemplate
@@ -54,10 +50,7 @@ final class AssertJDoubleTemplates {
     AbstractDoubleAssert<?> before(AbstractDoubleAssert<?> doubleAssert, double n) {
       return Refaster.anyOf(
           doubleAssert.isNotCloseTo(n, offset(0.0)),
-          doubleAssert.isNotCloseTo(Double.valueOf(n), offset(0.0)),
-          doubleAssert.isNotCloseTo(n, withPercentage(0.0)),
-          doubleAssert.isNotCloseTo(Double.valueOf(n), withPercentage(0.0)),
-          doubleAssert.isNotEqualTo(Double.valueOf(n)));
+          doubleAssert.isNotCloseTo(n, withPercentage(0.0)));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJFloatTemplates.java

@@ -36,11 +36,7 @@ final class AssertJFloatTemplates {
     @BeforeTemplate
     AbstractFloatAssert<?> before(AbstractFloatAssert<?> floatAssert, float n) {
       return Refaster.anyOf(
-          floatAssert.isCloseTo(n, offset(0F)),
-          floatAssert.isCloseTo(Float.valueOf(n), offset(0F)),
-          floatAssert.isCloseTo(n, withPercentage(0)),
-          floatAssert.isCloseTo(Float.valueOf(n), withPercentage(0)),
-          floatAssert.isEqualTo(Float.valueOf(n)));
+          floatAssert.isCloseTo(n, offset(0F)), floatAssert.isCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate
@@ -53,11 +49,7 @@ final class AssertJFloatTemplates {
     @BeforeTemplate
     AbstractFloatAssert<?> before(AbstractFloatAssert<?> floatAssert, float n) {
       return Refaster.anyOf(
-          floatAssert.isNotCloseTo(n, offset(0F)),
-          floatAssert.isNotCloseTo(Float.valueOf(n), offset(0F)),
-          floatAssert.isNotCloseTo(n, withPercentage(0)),
-          floatAssert.isNotCloseTo(Float.valueOf(n), withPercentage(0)),
-          floatAssert.isNotEqualTo(Float.valueOf(n)));
+          floatAssert.isNotCloseTo(n, offset(0F)), floatAssert.isNotCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJIntegerTemplates.java

@@ -15,11 +15,7 @@ final class AssertJIntegerTemplates {
     @BeforeTemplate
     AbstractIntegerAssert<?> before(AbstractIntegerAssert<?> intAssert, int n) {
       return Refaster.anyOf(
-          intAssert.isCloseTo(n, offset(0)),
-          intAssert.isCloseTo(Integer.valueOf(n), offset(0)),
-          intAssert.isCloseTo(n, withPercentage(0)),
-          intAssert.isCloseTo(Integer.valueOf(n), withPercentage(0)),
-          intAssert.isEqualTo(Integer.valueOf(n)));
+          intAssert.isCloseTo(n, offset(0)), intAssert.isCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate
@@ -32,11 +28,7 @@ final class AssertJIntegerTemplates {
     @BeforeTemplate
     AbstractIntegerAssert<?> before(AbstractIntegerAssert<?> intAssert, int n) {
       return Refaster.anyOf(
-          intAssert.isNotCloseTo(n, offset(0)),
-          intAssert.isNotCloseTo(Integer.valueOf(n), offset(0)),
-          intAssert.isNotCloseTo(n, withPercentage(0)),
-          intAssert.isNotCloseTo(Integer.valueOf(n), withPercentage(0)),
-          intAssert.isNotEqualTo(Integer.valueOf(n)));
+          intAssert.isNotCloseTo(n, offset(0)), intAssert.isNotCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJLongTemplates.java

@@ -15,11 +15,7 @@ final class AssertJLongTemplates {
     @BeforeTemplate
     AbstractLongAssert<?> before(AbstractLongAssert<?> longAssert, long n) {
       return Refaster.anyOf(
-          longAssert.isCloseTo(n, offset(0L)),
-          longAssert.isCloseTo(Long.valueOf(n), offset(0L)),
-          longAssert.isCloseTo(n, withPercentage(0)),
-          longAssert.isCloseTo(Long.valueOf(n), withPercentage(0)),
-          longAssert.isEqualTo(Long.valueOf(n)));
+          longAssert.isCloseTo(n, offset(0L)), longAssert.isCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate
@@ -32,11 +28,7 @@ final class AssertJLongTemplates {
     @BeforeTemplate
     AbstractLongAssert<?> before(AbstractLongAssert<?> longAssert, long n) {
       return Refaster.anyOf(
-          longAssert.isNotCloseTo(n, offset(0L)),
-          longAssert.isNotCloseTo(Long.valueOf(n), offset(0L)),
-          longAssert.isNotCloseTo(n, withPercentage(0)),
-          longAssert.isNotCloseTo(Long.valueOf(n), withPercentage(0)),
-          longAssert.isNotEqualTo(Long.valueOf(n)));
+          longAssert.isNotCloseTo(n, offset(0L)), longAssert.isNotCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJMapTemplates.java

@@ -0,0 +1,35 @@
+package tech.picnic.errorprone.refastertemplates;
+
+import com.google.common.collect.ImmutableMap;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.util.Map;
+import org.assertj.core.api.AbstractMapAssert;
+
+final class AssertJMapTemplates {
+  private AssertJMapTemplates() {}
+
+  static final class AbstractMapAssertContainsExactlyInAnyOrderEntriesOf<K, V> {
+    @BeforeTemplate
+    AbstractMapAssert<?, ?, K, V> before(AbstractMapAssert<?, ?, K, V> mapAssert, Map<K, V> map) {
+      return mapAssert.isEqualTo(map);
+    }
+
+    @AfterTemplate
+    AbstractMapAssert<?, ?, K, V> after(AbstractMapAssert<?, ?, K, V> mapAssert, Map<K, V> map) {
+      return mapAssert.containsExactlyInAnyOrderEntriesOf(map);
+    }
+  }
+
+  static final class AbstractMapAssertContainsExactlyEntriesOf<K, V> {
+    @BeforeTemplate
+    AbstractMapAssert<?, ?, K, V> before(AbstractMapAssert<?, ?, K, V> mapAssert, K key, V value) {
+      return mapAssert.containsExactlyInAnyOrderEntriesOf(ImmutableMap.of(key, value));
+    }
+
+    @AfterTemplate
+    AbstractMapAssert<?, ?, K, V> after(AbstractMapAssert<?, ?, K, V> mapAssert, K key, V value) {
+      return mapAssert.containsExactlyEntriesOf(ImmutableMap.of(key, value));
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJNumberTemplates.java

@@ -1,8 +1,12 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static org.assertj.core.api.Assertions.assertThat;
+
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.math.BigDecimal;
 import java.math.BigInteger;
 import org.assertj.core.api.AbstractBigDecimalAssert;
@@ -18,7 +22,7 @@ import org.assertj.core.api.NumberAssert;
 final class AssertJNumberTemplates {
   private AssertJNumberTemplates() {}
 
-  static final class NumberIsPositive {
+  static final class NumberAssertIsPositive {
     @BeforeTemplate
     AbstractByteAssert<?> before(AbstractByteAssert<?> numberAssert) {
       return Refaster.anyOf(
@@ -69,7 +73,7 @@ final class AssertJNumberTemplates {
     }
   }
 
-  static final class NumberIsNotPositive {
+  static final class NumberAssertIsNotPositive {
     @BeforeTemplate
     AbstractByteAssert<?> before(AbstractByteAssert<?> numberAssert) {
       return Refaster.anyOf(
@@ -120,7 +124,7 @@ final class AssertJNumberTemplates {
     }
   }
 
-  static final class NumberIsNegative {
+  static final class NumberAssertIsNegative {
     @BeforeTemplate
     AbstractByteAssert<?> before(AbstractByteAssert<?> numberAssert) {
       return Refaster.anyOf(
@@ -171,7 +175,7 @@ final class AssertJNumberTemplates {
     }
   }
 
-  static final class NumberIsNotNegative {
+  static final class NumberAssertIsNotNegative {
     @BeforeTemplate
     AbstractByteAssert<?> before(AbstractByteAssert<?> numberAssert) {
       return Refaster.anyOf(
@@ -221,4 +225,40 @@ final class AssertJNumberTemplates {
       return numberAssert.isNotNegative();
     }
   }
+
+  static final class AssertThatIsOdd {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(int number) {
+      return assertThat(number % 2).isEqualTo(1);
+    }
+
+    @BeforeTemplate
+    AbstractLongAssert<?> before(long number) {
+      return assertThat(number % 2).isEqualTo(1);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    NumberAssert<?, ?> after(long number) {
+      return assertThat(number).isOdd();
+    }
+  }
+
+  static final class AssertThatIsEven {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(int number) {
+      return assertThat(number % 2).isEqualTo(0);
+    }
+
+    @BeforeTemplate
+    AbstractLongAssert<?> before(long number) {
+      return assertThat(number % 2).isEqualTo(0);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    NumberAssert<?, ?> after(long number) {
+      return assertThat(number).isEven();
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJObjectTemplates.java

@@ -1,8 +1,8 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -21,7 +21,7 @@ final class AssertJObjectTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ObjectAssert<S> after(S object) {
       return assertThat(object).isInstanceOf(Refaster.<T>clazz());
     }
@@ -34,7 +34,7 @@ final class AssertJObjectTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ObjectAssert<S> after(S object) {
       return assertThat(object).isNotInstanceOf(Refaster.<T>clazz());
     }
@@ -47,7 +47,7 @@ final class AssertJObjectTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ObjectAssert<S> after(S object1, T object2) {
       return assertThat(object1).isEqualTo(object2);
     }
@@ -60,7 +60,7 @@ final class AssertJObjectTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ObjectAssert<S> after(S object1, T object2) {
       return assertThat(object1).isNotEqualTo(object2);
     }
@@ -73,7 +73,7 @@ final class AssertJObjectTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ObjectAssert<T> after(T object, String str) {
       return assertThat(object).hasToString(str);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJOptionalTemplates.java

@@ -1,8 +1,8 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -26,7 +26,7 @@ final class AssertJOptionalTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, T> after(Optional<T> optional) {
       return assertThat(optional).get();
     }
@@ -53,7 +53,7 @@ final class AssertJOptionalTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     OptionalAssert<T> after(Optional<T> optional) {
       return assertThat(optional).isPresent();
     }
@@ -80,7 +80,7 @@ final class AssertJOptionalTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     OptionalAssert<T> after(Optional<T> optional) {
       return assertThat(optional).isEmpty();
     }
@@ -122,7 +122,7 @@ final class AssertJOptionalTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, T> after(Optional<T> optional, Predicate<? super T> predicate) {
       return assertThat(optional).get().matches(predicate);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJShortTemplates.java

@@ -15,11 +15,7 @@ final class AssertJShortTemplates {
     @BeforeTemplate
     AbstractShortAssert<?> before(AbstractShortAssert<?> shortAssert, short n) {
       return Refaster.anyOf(
-          shortAssert.isCloseTo(n, offset((short) 0)),
-          shortAssert.isCloseTo(Short.valueOf(n), offset((short) 0)),
-          shortAssert.isCloseTo(n, withPercentage(0)),
-          shortAssert.isCloseTo(Short.valueOf(n), withPercentage(0)),
-          shortAssert.isEqualTo(Short.valueOf(n)));
+          shortAssert.isCloseTo(n, offset((short) 0)), shortAssert.isCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate
@@ -33,10 +29,7 @@ final class AssertJShortTemplates {
     AbstractShortAssert<?> before(AbstractShortAssert<?> shortAssert, short n) {
       return Refaster.anyOf(
           shortAssert.isNotCloseTo(n, offset((short) 0)),
-          shortAssert.isNotCloseTo(Short.valueOf(n), offset((short) 0)),
-          shortAssert.isNotCloseTo(n, withPercentage(0)),
-          shortAssert.isNotCloseTo(Short.valueOf(n), withPercentage(0)),
-          shortAssert.isNotEqualTo(Short.valueOf(n)));
+          shortAssert.isNotCloseTo(n, withPercentage(0)));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJStringTemplates.java

@@ -1,8 +1,8 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
@@ -31,7 +31,7 @@ final class AssertJStringTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(String string) {
       assertThat(string).isEmpty();
     }
@@ -56,9 +56,35 @@ final class AssertJStringTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractAssert<?, ?> after(String string) {
       return assertThat(string).isNotEmpty();
     }
   }
+
+  static final class AssertThatMatches {
+    @BeforeTemplate
+    AbstractAssert<?, ?> before(String string, String regex) {
+      return assertThat(string.matches(regex)).isTrue();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractAssert<?, ?> after(String string, String regex) {
+      return assertThat(string).matches(regex);
+    }
+  }
+
+  static final class AssertThatDoesNotMatch {
+    @BeforeTemplate
+    AbstractAssert<?, ?> before(String string, String regex) {
+      return assertThat(string.matches(regex)).isFalse();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractAssert<?, ?> after(String string, String regex) {
+      return assertThat(string).doesNotMatch(regex);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJTemplates.java

@@ -1,5 +1,6 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.google.common.collect.ImmutableBiMap;
@@ -12,7 +13,6 @@ import com.google.common.collect.ImmutableSortedMultiset;
 import com.google.common.collect.ImmutableSortedSet;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Multiset;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -39,6 +39,7 @@ import java.util.stream.Collector;
 import java.util.stream.Stream;
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AbstractBooleanAssert;
+import org.assertj.core.api.AbstractCollectionAssert;
 import org.assertj.core.api.AbstractComparableAssert;
 import org.assertj.core.api.AbstractDoubleAssert;
 import org.assertj.core.api.AbstractIntegerAssert;
@@ -96,7 +97,6 @@ import tech.picnic.errorprone.refaster.util.IsArray;
 // XXX: Right now we use and import `Offset.offset` and `Percentage.withPercentage`. Use the AssertJ
 // methods instead. (Also in the TestNG migration.)
 //      ^ Also for `Tuple`!
-// XXX: Use `assertThatIllegalArgumentException` and variants.
 // XXX: `assertThatCode(x).isInstanceOf(clazz)` -> `assertThatThrownBy(x).isInstanceOf(clazz)`
 // (etc.)
 // XXX: Look into using Assertions#contentOf(URL url, Charset charset) instead of our own test
@@ -136,7 +136,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     OptionalDoubleAssert after(OptionalDouble optional, double expected) {
       return assertThat(optional).hasValue(expected);
     }
@@ -155,7 +155,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     OptionalIntAssert after(OptionalInt optional, int expected) {
       return assertThat(optional).hasValue(expected);
     }
@@ -174,7 +174,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     OptionalLongAssert after(OptionalLong optional, long expected) {
       return assertThat(optional).hasValue(expected);
     }
@@ -364,6 +364,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ObjectEnumerableAssert<?, S> after(Set<S> set, T element) {
       return assertThat(set).containsExactly(element);
     }
@@ -428,7 +429,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Collection<E> iterable) {
       assertThat(iterable).isEmpty();
     }
@@ -452,7 +453,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     IterableAssert<E> after(Iterable<E> iterable) {
       return assertThat(iterable).isNotEmpty();
     }
@@ -470,7 +471,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     IterableAssert<E> after(Iterable<E> iterable, int length) {
       return assertThat(iterable).hasSize(length);
     }
@@ -483,7 +484,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     IterableAssert<S> after(Iterable<S> iterable, T element) {
       return assertThat(iterable).containsExactly(element);
     }
@@ -500,7 +501,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     IterableAssert<S> after(Iterable<S> iterable, T element) {
       return assertThat(iterable).containsExactly(element);
     }
@@ -517,7 +518,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(List<S> list1, List<T> list2) {
       return assertThat(list1).containsExactlyElementsOf(list2);
     }
@@ -529,15 +530,15 @@ final class AssertJTemplates {
 
   static final class AssertThatSetsAreEqual<S, T extends S> {
     @BeforeTemplate
-    IterableAssert<S> before(Set<S> set1, Set<T> set2) {
+    AbstractCollectionAssert<?, ?, S, ?> before(Set<S> set1, Set<T> set2) {
       return Refaster.anyOf(
           assertThat(set1).isEqualTo(set2),
           assertThat(set1).containsExactlyInAnyOrderElementsOf(set2));
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
-    IterableAssert<S> after(Set<S> set1, Set<T> set2) {
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractCollectionAssert<?, ?, S, ?> after(Set<S> set1, Set<T> set2) {
       return assertThat(set1).hasSameElementsAs(set2);
     }
   }
@@ -548,13 +549,13 @@ final class AssertJTemplates {
 
   static final class AssertThatMultisetsAreEqual<S, T extends S> {
     @BeforeTemplate
-    IterableAssert<S> before(Multiset<S> multiset1, Multiset<T> multiset2) {
+    AbstractCollectionAssert<?, ?, S, ?> before(Multiset<S> multiset1, Multiset<T> multiset2) {
       return assertThat(multiset1).isEqualTo(multiset2);
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
-    IterableAssert<S> after(Multiset<S> multiset1, Multiset<T> multiset2) {
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractCollectionAssert<?, ?, S, ?> after(Multiset<S> multiset1, Multiset<T> multiset2) {
       return assertThat(multiset1).containsExactlyInAnyOrderElementsOf(multiset2);
     }
   }
@@ -631,7 +632,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Map<K, V> map) {
       assertThat(map).isEmpty();
     }
@@ -668,7 +669,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     MapAssert<K, V> after(Map<K, V> map) {
       return assertThat(map).isNotEmpty();
     }
@@ -683,7 +684,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     MapAssert<K, V> after(Map<K, V> map, int length) {
       return assertThat(map).hasSize(length);
     }
@@ -697,7 +698,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     MapAssert<K, V> after(Map<K, V> map1, Map<K, V> map2) {
       return assertThat(map1).hasSameSizeAs(map2);
     }
@@ -711,7 +712,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     MapAssert<K, V> after(Map<K, V> map, K key) {
       return assertThat(map).containsKey(key);
     }
@@ -724,7 +725,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     MapAssert<K, V> after(Map<K, V> map, K key) {
       return assertThat(map).doesNotContainKey(key);
     }
@@ -737,7 +738,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     MapAssert<K, V> after(Map<K, V> map, K key, V value) {
       return assertThat(map).containsEntry(key, value);
     }
@@ -762,7 +763,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).containsAnyElementsOf(iterable);
     }
@@ -783,7 +784,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, U[] array) {
       return assertThat(stream).containsAnyOf(array);
     }
@@ -807,7 +808,7 @@ final class AssertJTemplates {
 
     @AfterTemplate
     @SuppressWarnings("ObjectEnumerableContainsOneElement" /* Not a true singleton. */)
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).containsAnyOf(elements);
     }
@@ -828,7 +829,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).containsAll(iterable);
     }
@@ -849,7 +850,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, U[] array) {
       return assertThat(stream).contains(array);
     }
@@ -872,7 +873,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).contains(elements);
     }
@@ -887,7 +888,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).containsExactlyElementsOf(iterable);
     }
@@ -902,7 +903,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, U[] array) {
       return assertThat(stream).containsExactly(array);
     }
@@ -918,7 +919,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).containsExactly(elements);
     }
@@ -934,13 +935,13 @@ final class AssertJTemplates {
     }
 
     @BeforeTemplate
-    IterableAssert<T> before2(
+    AbstractCollectionAssert<?, ?, T, ?> before2(
         Stream<S> stream, Collector<S, ?, ? extends Multiset<T>> collector, Iterable<U> iterable) {
       return assertThat(stream.collect(collector)).containsExactlyInAnyOrderElementsOf(iterable);
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).containsExactlyInAnyOrderElementsOf(iterable);
     }
@@ -955,13 +956,13 @@ final class AssertJTemplates {
     }
 
     @BeforeTemplate
-    IterableAssert<T> before2(
+    AbstractCollectionAssert<?, ?, T, ?> before2(
         Stream<S> stream, Collector<S, ?, ? extends Multiset<T>> collector, U[] array) {
       return assertThat(stream.collect(collector)).containsExactlyInAnyOrder(array);
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, U[] array) {
       return assertThat(stream).containsExactlyInAnyOrder(array);
     }
@@ -979,7 +980,7 @@ final class AssertJTemplates {
 
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsExactlyInAnyOrder" /* Varargs converted to array. */)
-    IterableAssert<T> before2(
+    AbstractCollectionAssert<?, ?, T, ?> before2(
         Stream<S> stream, Collector<S, ?, ? extends Multiset<T>> collector, @Repeated U elements) {
       return assertThat(stream.collect(collector))
           .containsExactlyInAnyOrder(Refaster.asVarargs(elements));
@@ -987,7 +988,7 @@ final class AssertJTemplates {
 
     @AfterTemplate
     @SuppressWarnings("ObjectEnumerableContainsExactlyOneElement" /* Not a true singleton. */)
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).containsExactlyInAnyOrder(elements);
     }
@@ -1008,7 +1009,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).containsSequence(iterable);
     }
@@ -1025,7 +1026,7 @@ final class AssertJTemplates {
 
     @AfterTemplate
     @SuppressWarnings("ObjectEnumerableContainsOneElement" /* Not a true singleton. */)
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).containsSequence(elements);
     }
@@ -1046,7 +1047,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).containsSubsequence(iterable);
     }
@@ -1064,7 +1065,7 @@ final class AssertJTemplates {
 
     @AfterTemplate
     @SuppressWarnings("ObjectEnumerableContainsOneElement" /* Not a true singleton. */)
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).containsSubsequence(elements);
     }
@@ -1085,7 +1086,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).doesNotContainAnyElementsOf(iterable);
     }
@@ -1106,7 +1107,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, U[] array) {
       return assertThat(stream).doesNotContain(array);
     }
@@ -1129,7 +1130,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).doesNotContain(elements);
     }
@@ -1150,7 +1151,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).doesNotContainSequence(iterable);
     }
@@ -1168,7 +1169,7 @@ final class AssertJTemplates {
 
     @AfterTemplate
     @SuppressWarnings("ObjectEnumerableDoesNotContainOneElement" /* Not a true singleton. */)
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).doesNotContainSequence(elements);
     }
@@ -1189,7 +1190,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, Iterable<U> iterable) {
       return assertThat(stream).hasSameElementsAs(iterable);
     }
@@ -1210,7 +1211,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, U[] array) {
       return assertThat(stream).containsOnly(array);
     }
@@ -1233,7 +1234,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).containsOnly(elements);
     }
@@ -1266,7 +1267,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, U[] iterable) {
       return assertThat(stream).isSubsetOf(iterable);
     }
@@ -1289,7 +1290,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ListAssert<S> after(Stream<S> stream, @Repeated U elements) {
       return assertThat(stream).isSubsetOf(elements);
     }
@@ -1308,7 +1309,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Stream<S> stream) {
       assertThat(stream).isEmpty();
     }
@@ -1327,7 +1328,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Stream<S> stream) {
       assertThat(stream).isNotEmpty();
     }
@@ -1340,7 +1341,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Stream<T> stream, int size) {
       assertThat(stream).hasSize(size);
     }
@@ -1357,7 +1358,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Predicate<T> predicate, T object) {
       assertThat(predicate).accepts(object);
     }
@@ -1370,7 +1371,7 @@ final class AssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Predicate<T> predicate, T object) {
       assertThat(predicate).rejects(object);
     }
@@ -2211,7 +2212,7 @@ final class AssertJTemplates {
   //        }
   //
   //        @AfterTemplate
-  //        @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+  //        @UseImportPolicy(STATIC_IMPORT_ALWAYS)
   //        IterableAssert<E> after(Iterable<E> iterable, E expected) {
   //            return assertThat(iterable).containsExactly(expected);
   //        }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJThrowingCallableTemplates.java

@@ -0,0 +1,445 @@
+package tech.picnic.errorprone.refastertemplates;
+
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static org.assertj.core.api.Assertions.assertThatExceptionOfType;
+import static org.assertj.core.api.Assertions.assertThatIOException;
+import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException;
+import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
+import static org.assertj.core.api.Assertions.assertThatNullPointerException;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.Repeated;
+import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import java.io.IOException;
+import org.assertj.core.api.AbstractObjectAssert;
+import org.assertj.core.api.AbstractThrowableAssert;
+import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
+
+/**
+ * Refaster templates related to AssertJ assertions over expressions that may throw a {@link
+ * Throwable} subtype.
+ *
+ * <p>For reasons of consistency we prefer {@link
+ * org.assertj.core.api.Assertions#assertThatThrownBy} over static methods for specific exception
+ * types. Note that only the most common assertion expressions are rewritten here; covering all
+ * cases would require the implementation of an Error Prone check instead.
+ */
+final class AssertJThrowingCallableTemplates {
+  private AssertJThrowingCallableTemplates() {}
+
+  static final class AssertThatThrownByIllegalArgumentException {
+    @BeforeTemplate
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable) {
+      return assertThatIllegalArgumentException().isThrownBy(throwingCallable);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable) {
+      return assertThatThrownBy(throwingCallable).isInstanceOf(IllegalArgumentException.class);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalArgumentExceptionHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalArgumentException().isThrownBy(throwingCallable).withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessage(message);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalArgumentExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatIllegalArgumentException()
+          .isThrownBy(throwingCallable)
+          .withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalArgumentExceptionHasMessageStartingWith {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalArgumentException()
+          .isThrownBy(throwingCallable)
+          .withMessageStartingWith(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessageStartingWith(message);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalArgumentExceptionHasMessageContaining {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalArgumentException()
+          .isThrownBy(throwingCallable)
+          .withMessageContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessageContaining(message);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalArgumentExceptionHasMessageNotContainingAny {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, @Repeated CharSequence values) {
+      return assertThatIllegalArgumentException()
+          .isThrownBy(throwingCallable)
+          .withMessageNotContainingAny(values);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, @Repeated CharSequence values) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessageNotContainingAny(values);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalStateException {
+    @BeforeTemplate
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable) {
+      return assertThatIllegalStateException().isThrownBy(throwingCallable);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable) {
+      return assertThatThrownBy(throwingCallable).isInstanceOf(IllegalStateException.class);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalStateExceptionHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalStateException().isThrownBy(throwingCallable).withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalStateException.class)
+          .hasMessage(message);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalStateExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatIllegalStateException()
+          .isThrownBy(throwingCallable)
+          .withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalStateException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalStateExceptionHasMessageStartingWith {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalStateException()
+          .isThrownBy(throwingCallable)
+          .withMessageStartingWith(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalStateException.class)
+          .hasMessageStartingWith(message);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalStateExceptionHasMessageContaining {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalStateException()
+          .isThrownBy(throwingCallable)
+          .withMessageContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalStateException.class)
+          .hasMessageContaining(message);
+    }
+  }
+
+  static final class AssertThatThrownByIllegalStateExceptionHasMessageNotContaining {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalStateException()
+          .isThrownBy(throwingCallable)
+          .withMessageNotContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalStateException.class)
+          .hasMessageNotContaining(message);
+    }
+  }
+
+  static final class AssertThatThrownByNullPointerException {
+    @BeforeTemplate
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable) {
+      return assertThatNullPointerException().isThrownBy(throwingCallable);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable) {
+      return assertThatThrownBy(throwingCallable).isInstanceOf(NullPointerException.class);
+    }
+  }
+
+  static final class AssertThatThrownByNullPointerExceptionHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByNullPointerException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatNullPointerException().isThrownBy(throwingCallable).withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(NullPointerException.class)
+          .hasMessage(message);
+    }
+  }
+
+  static final class AssertThatThrownByNullPointerExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByNullPointerException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatNullPointerException()
+          .isThrownBy(throwingCallable)
+          .withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(NullPointerException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
+  static final class AssertThatThrownByNullPointerExceptionHasMessageStartingWith {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByNullPointerException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatNullPointerException()
+          .isThrownBy(throwingCallable)
+          .withMessageStartingWith(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(NullPointerException.class)
+          .hasMessageStartingWith(message);
+    }
+  }
+
+  static final class AssertThatThrownByIOException {
+    @BeforeTemplate
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable) {
+      return assertThatIOException().isThrownBy(throwingCallable);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable) {
+      return assertThatThrownBy(throwingCallable).isInstanceOf(IOException.class);
+    }
+  }
+
+  static final class AssertThatThrownByIOExceptionHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIOException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIOException().isThrownBy(throwingCallable).withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IOException.class)
+          .hasMessage(message);
+    }
+  }
+
+  static final class AssertThatThrownByIOExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIOException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatIOException().isThrownBy(throwingCallable).withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IOException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
+  static final class AssertThatThrownBy {
+    @BeforeTemplate
+    AbstractObjectAssert<?, ?> before(
+        Class<? extends Throwable> exceptionType, ThrowingCallable throwingCallable) {
+      return assertThatExceptionOfType(exceptionType).isThrownBy(throwingCallable);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        Class<? extends Throwable> exceptionType, ThrowingCallable throwingCallable) {
+      return assertThatThrownBy(throwingCallable).isInstanceOf(exceptionType);
+    }
+  }
+
+  static final class AssertThatThrownByHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownBy" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        Class<? extends Throwable> exceptionType,
+        ThrowingCallable throwingCallable,
+        String message) {
+      return assertThatExceptionOfType(exceptionType)
+          .isThrownBy(throwingCallable)
+          .withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        Class<? extends Throwable> exceptionType,
+        ThrowingCallable throwingCallable,
+        String message) {
+      return assertThatThrownBy(throwingCallable).isInstanceOf(exceptionType).hasMessage(message);
+    }
+  }
+
+  // XXX: Drop this template in favour of a generic Error Prone check which flags
+  // `String.format(...)` arguments to a wide range of format methods.
+  static final class AbstractThrowableAssertHasMessage {
+    @BeforeTemplate
+    AbstractThrowableAssert<?, ? extends Throwable> before(
+        AbstractThrowableAssert<?, ? extends Throwable> abstractThrowableAssert,
+        String message,
+        @Repeated Object parameters) {
+      return abstractThrowableAssert.hasMessage(String.format(message, parameters));
+    }
+
+    @AfterTemplate
+    AbstractThrowableAssert<?, ? extends Throwable> after(
+        AbstractThrowableAssert<?, ? extends Throwable> abstractThrowableAssert,
+        String message,
+        @Repeated Object parameters) {
+      return abstractThrowableAssert.hasMessage(message, parameters);
+    }
+  }
+
+  // XXX: Drop this template in favour of a generic Error Prone check which flags
+  // `String.format(...)` arguments to a wide range of format methods.
+  static final class AbstractThrowableAssertWithFailMessage {
+    @BeforeTemplate
+    AbstractThrowableAssert<?, ? extends Throwable> before(
+        AbstractThrowableAssert<?, ? extends Throwable> abstractThrowableAssert,
+        String message,
+        @Repeated Object args) {
+      return abstractThrowableAssert.withFailMessage(String.format(message, args));
+    }
+
+    @AfterTemplate
+    AbstractThrowableAssert<?, ? extends Throwable> after(
+        AbstractThrowableAssert<?, ? extends Throwable> abstractThrowableAssert,
+        String message,
+        @Repeated Object args) {
+      return abstractThrowableAssert.withFailMessage(message, args);
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssortedTemplates.java

@@ -3,6 +3,8 @@ package tech.picnic.errorprone.refastertemplates;
 import static com.google.common.base.Preconditions.checkElementIndex;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.Sets.toImmutableEnumSet;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.util.Collections.disjoint;
 import static java.util.Objects.checkIndex;
 
 import com.google.common.base.Splitter;
@@ -11,7 +13,6 @@ import com.google.common.collect.Iterables;
 import com.google.common.collect.Iterators;
 import com.google.common.collect.Sets;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -92,7 +93,7 @@ final class AssortedTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableSet<T> after(Stream<T> stream) {
       return stream.collect(toImmutableEnumSet());
     }
@@ -162,7 +163,7 @@ final class AssortedTemplates {
 
     @AfterTemplate
     boolean after(Set<T> set1, Set<T> set2) {
-      return Collections.disjoint(set1, set2);
+      return disjoint(set1, set2);
     }
   }
 
@@ -177,15 +178,15 @@ final class AssortedTemplates {
     @BeforeTemplate
     boolean before(Collection<T> collection1, Collection<T> collection2) {
       return Refaster.anyOf(
-          Collections.disjoint(ImmutableSet.copyOf(collection1), collection2),
-          Collections.disjoint(new HashSet<>(collection1), collection2),
-          Collections.disjoint(collection1, ImmutableSet.copyOf(collection2)),
-          Collections.disjoint(collection1, new HashSet<>(collection2)));
+          disjoint(ImmutableSet.copyOf(collection1), collection2),
+          disjoint(new HashSet<>(collection1), collection2),
+          disjoint(collection1, ImmutableSet.copyOf(collection2)),
+          disjoint(collection1, new HashSet<>(collection2)));
     }
 
     @AfterTemplate
     boolean after(Collection<T> collection1, Collection<T> collection2) {
-      return Collections.disjoint(collection1, collection2);
+      return disjoint(collection1, collection2);
     }
   }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/CollectionTemplates.java

@@ -15,6 +15,7 @@ import java.util.List;
 import java.util.NavigableSet;
 import java.util.Optional;
 import java.util.Queue;
+import java.util.Set;
 import java.util.SortedSet;
 import java.util.function.IntFunction;
 import java.util.stream.Stream;
@@ -129,31 +130,32 @@ final class CollectionTemplates {
     }
   }
 
-  static final class CollectionRemoveAllFromCollectionBlock<T, S extends T> {
+  static final class SetRemoveAllCollection<T, S extends T> {
     @BeforeTemplate
-    void before(Collection<T> removeTo, Collection<S> elementsToRemove) {
-      elementsToRemove.forEach(removeTo::remove);
+    void before(Set<T> removeFrom, Collection<S> elementsToRemove) {
+      elementsToRemove.forEach(removeFrom::remove);
     }
 
     @BeforeTemplate
-    void before2(Collection<T> removeTo, Collection<S> elementsToRemove) {
+    void before2(Set<T> removeFrom, Collection<S> elementsToRemove) {
       for (T element : elementsToRemove) {
-        removeTo.remove(element);
+        removeFrom.remove(element);
       }
     }
 
     // XXX: This method is identical to `before2` except for the loop type. Make Refaster smarter so
-    // that this is supported out of the box.
+    // that this is supported out of the box. After doing so, also drop the `S extends T` type
+    // constraint; ideally this check applies to any `S`.
     @BeforeTemplate
-    void before3(Collection<T> removeTo, Collection<S> elementsToRemove) {
+    void before3(Set<T> removeFrom, Collection<S> elementsToRemove) {
       for (S element : elementsToRemove) {
-        removeTo.remove(element);
+        removeFrom.remove(element);
       }
     }
 
     @AfterTemplate
-    void after(Collection<T> removeTo, Collection<S> elementsToRemove) {
-      removeTo.removeAll(elementsToRemove);
+    void after(Set<T> removeFrom, Collection<S> elementsToRemove) {
+      removeFrom.removeAll(elementsToRemove);
     }
   }
 
@@ -187,7 +189,7 @@ final class CollectionTemplates {
    * Don't call {@link ImmutableCollection#asList()} if the result is going to be streamed; stream
    * directly.
    */
-  static final class ImmutableCollectionAsListToStream<T> {
+  static final class ImmutableCollectionStream<T> {
     @BeforeTemplate
     Stream<T> before(ImmutableCollection<T> collection) {
       return collection.asList().stream();

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ComparatorTemplates.java

@@ -1,5 +1,6 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.comparing;
 import static java.util.Comparator.comparingDouble;
 import static java.util.Comparator.comparingInt;
@@ -11,7 +12,6 @@ import static java.util.function.Function.identity;
 import com.google.common.collect.Comparators;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -38,7 +38,7 @@ final class ComparatorTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<T> after() {
       return naturalOrder();
     }
@@ -52,7 +52,7 @@ final class ComparatorTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<T> after() {
       return reverseOrder();
     }
@@ -66,7 +66,7 @@ final class ComparatorTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<T> after(Comparator<T> cmp) {
       return cmp;
     }
@@ -93,7 +93,7 @@ final class ComparatorTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<S> after(Comparator<S> cmp, Function<? super S, ? extends T> function) {
       return cmp.thenComparing(function, reverseOrder());
     }
@@ -180,7 +180,7 @@ final class ComparatorTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<T> after(Comparator<T> cmp) {
       return cmp.thenComparing(naturalOrder());
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/EqualityTemplates.java

@@ -20,7 +20,7 @@ final class EqualityTemplates {
      * remaining reference-based equality checks.
      */
     // XXX: This Refaster rule is the topic of https://github.com/google/error-prone/issues/559. We
-    // work around the issue by selecting the "largest replacements". See RefasterCheck.
+    // work around the issue by selecting the "largest replacements". See the `Refaster` check.
     @BeforeTemplate
     boolean before(T a, T b) {
       return Refaster.anyOf(a.equals(b), Objects.equals(a, b));
@@ -34,9 +34,8 @@ final class EqualityTemplates {
   }
 
   /** Prefer {@link Object#equals(Object)} over the equivalent lambda function. */
-  // XXX: As it stands, this rule is a special case of what `MethodReferenceUsageCheck` tries to
-  // achieve. If/when `MethodReferenceUsageCheck` becomes production ready, we should simply drop
-  // this check.
+  // XXX: As it stands, this rule is a special case of what `MethodReferenceUsage` tries to achieve.
+  // If/when `MethodReferenceUsage` becomes production ready, we should simply drop this check.
   // XXX: Alternatively, the rule should be replaced with a plugin which also identifies cases where
   // the arguments are swapped but simplification is possible anyway, by virtue of `v` being
   // non-null.

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableListMultimapTemplates.java

@@ -2,6 +2,7 @@ package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableListMultimap.flatteningToImmutableListMultimap;
 import static com.google.common.collect.ImmutableListMultimap.toImmutableListMultimap;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.function.Function.identity;
 
 import com.google.common.collect.ImmutableListMultimap;
@@ -12,7 +13,6 @@ import com.google.common.collect.Multimaps;
 import com.google.common.collect.SetMultimap;
 import com.google.common.collect.SortedSetMultimap;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -92,7 +92,7 @@ final class ImmutableListMultimapTemplates {
    */
   static final class EntryToImmutableListMultimap<K, V> {
     @BeforeTemplate
-    ImmutableMultimap<K, V> before(Map.Entry<? extends K, ? extends V> entry) {
+    ImmutableListMultimap<K, V> before(Map.Entry<? extends K, ? extends V> entry) {
       return Refaster.anyOf(
           ImmutableListMultimap.<K, V>builder().put(entry).build(),
           Stream.of(entry)
@@ -161,7 +161,7 @@ final class ImmutableListMultimapTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableListMultimap<K, V> after(Stream<E> stream) {
       return stream.collect(toImmutableListMultimap(e -> keyFunction(e), e -> valueFunction(e)));
     }
@@ -272,17 +272,4 @@ final class ImmutableListMultimapTemplates {
       return ImmutableListMultimap.copyOf(Multimaps.transformValues(multimap, transformation));
     }
   }
-
-  /** Don't unnecessarily copy an {@link ImmutableListMultimap}. */
-  static final class ImmutableListMultimapCopyOfImmutableListMultimap<K, V> {
-    @BeforeTemplate
-    ImmutableListMultimap<K, V> before(ImmutableListMultimap<K, V> multimap) {
-      return ImmutableListMultimap.copyOf(multimap);
-    }
-
-    @AfterTemplate
-    ImmutableListMultimap<K, V> after(ImmutableListMultimap<K, V> multimap) {
-      return multimap;
-    }
-  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableListTemplates.java

@@ -2,21 +2,20 @@ package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.util.Collections.emptyList;
+import static java.util.Collections.singletonList;
 import static java.util.Comparator.naturalOrder;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Comparator;
 import java.util.Iterator;
 import java.util.List;
@@ -41,37 +40,6 @@ final class ImmutableListTemplates {
     }
   }
 
-  /** Prefer {@link ImmutableList#of()} over more contrived alternatives. */
-  static final class EmptyImmutableList<T> {
-    @BeforeTemplate
-    ImmutableList<T> before() {
-      return Refaster.anyOf(
-          ImmutableList.<T>builder().build(), Stream.<T>empty().collect(toImmutableList()));
-    }
-
-    @AfterTemplate
-    ImmutableList<T> after() {
-      return ImmutableList.of();
-    }
-  }
-
-  /**
-   * Prefer {@link ImmutableList#of(Object)} over alternatives that don't communicate the
-   * immutability of the resulting list at the type level.
-   */
-  // XXX: Note that this rewrite rule is incorrect for nullable elements.
-  static final class SingletonImmutableList<T> {
-    @BeforeTemplate
-    List<T> before(T element) {
-      return Collections.singletonList(element);
-    }
-
-    @AfterTemplate
-    ImmutableList<T> after(T element) {
-      return ImmutableList.of(element);
-    }
-  }
-
   /**
    * Prefer {@link ImmutableList#copyOf(Iterable)} and variants over more contrived alternatives.
    */
@@ -108,39 +76,20 @@ final class ImmutableListTemplates {
     }
   }
 
-  /** Prefer {@link ImmutableList#toImmutableList()} over the more verbose alternative. */
-  // XXX: Once the code base has been sufficiently cleaned up, we might want to also rewrite
-  // `Collectors.toList(`), with the caveat that it allows mutation (though this cannot be relied
-  // upon) as well as nulls. Another option is to explicitly rewrite those variants to
-  // `Collectors.toSet(ArrayList::new)`.
+  /** Prefer {@link ImmutableList#toImmutableList()} over less idiomatic alternatives. */
   static final class StreamToImmutableList<T> {
     @BeforeTemplate
     ImmutableList<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableList.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableList::copyOf)));
+      return ImmutableList.copyOf(stream.iterator());
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableList<T> after(Stream<T> stream) {
       return stream.collect(toImmutableList());
     }
   }
 
-  /** Don't call {@link ImmutableList#asList()}; it is a no-op. */
-  static final class ImmutableListAsList<T> {
-    @BeforeTemplate
-    ImmutableList<T> before(ImmutableList<T> list) {
-      return list.asList();
-    }
-
-    @AfterTemplate
-    ImmutableList<T> after(ImmutableList<T> list) {
-      return list;
-    }
-  }
-
   /** Prefer {@link ImmutableList#sortedCopyOf(Iterable)} over more contrived alternatives. */
   static final class ImmutableListSortedCopyOf<T extends Comparable<? super T>> {
     @BeforeTemplate
@@ -194,9 +143,122 @@ final class ImmutableListTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableList<T> after(Stream<T> stream) {
       return stream.collect(toImmutableSet()).asList();
     }
   }
+
+  /**
+   * Prefer {@link ImmutableList#of()} over more contrived alternatives or alternatives that don't
+   * communicate the immutability of the resulting list at the type level.
+   */
+  // XXX: The `Stream` variant may be too contrived to warrant inclusion. Review its usage if/when
+  // this and similar Refaster templates are replaced with an Error Prone check.
+  static final class ImmutableListOf<T> {
+    @BeforeTemplate
+    List<T> before() {
+      return Refaster.anyOf(
+          ImmutableList.<T>builder().build(),
+          Stream.<T>empty().collect(toImmutableList()),
+          emptyList(),
+          List.of());
+    }
+
+    @AfterTemplate
+    ImmutableList<T> after() {
+      return ImmutableList.of();
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableList#of(Object)} over more contrived alternatives or alternatives that
+   * don't communicate the immutability of the resulting list at the type level.
+   */
+  // XXX: Note that the replacement of `Collections#singletonList` is incorrect for nullable
+  // elements.
+  static final class ImmutableListOf1<T> {
+    @BeforeTemplate
+    List<T> before(T e1) {
+      return Refaster.anyOf(
+          ImmutableList.<T>builder().add(e1).build(), singletonList(e1), List.of(e1));
+    }
+
+    @AfterTemplate
+    ImmutableList<T> after(T e1) {
+      return ImmutableList.of(e1);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableList#of(Object, Object)} over alternatives that don't communicate the
+   * immutability of the resulting list at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableList.builder()` usages.
+  static final class ImmutableListOf2<T> {
+    @BeforeTemplate
+    List<T> before(T e1, T e2) {
+      return List.of(e1, e2);
+    }
+
+    @AfterTemplate
+    ImmutableList<T> after(T e1, T e2) {
+      return ImmutableList.of(e1, e2);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableList#of(Object, Object, Object)} over alternatives that don't
+   * communicate the immutability of the resulting list at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableList.builder()` usages.
+  static final class ImmutableListOf3<T> {
+    @BeforeTemplate
+    List<T> before(T e1, T e2, T e3) {
+      return List.of(e1, e2, e3);
+    }
+
+    @AfterTemplate
+    ImmutableList<T> after(T e1, T e2, T e3) {
+      return ImmutableList.of(e1, e2, e3);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableList#of(Object, Object, Object, Object)} over alternatives that don't
+   * communicate the immutability of the resulting list at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableList.builder()` usages.
+  static final class ImmutableListOf4<T> {
+    @BeforeTemplate
+    List<T> before(T e1, T e2, T e3, T e4) {
+      return List.of(e1, e2, e3, e4);
+    }
+
+    @AfterTemplate
+    ImmutableList<T> after(T e1, T e2, T e3, T e4) {
+      return ImmutableList.of(e1, e2, e3, e4);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableList#of(Object, Object, Object, Object, Object)} over alternatives that
+   * don't communicate the immutability of the resulting list at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableList.builder()` usages.
+  static final class ImmutableListOf5<T> {
+    @BeforeTemplate
+    List<T> before(T e1, T e2, T e3, T e4, T e5) {
+      return List.of(e1, e2, e3, e4, e5);
+    }
+
+    @AfterTemplate
+    ImmutableList<T> after(T e1, T e2, T e3, T e4, T e5) {
+      return ImmutableList.of(e1, e2, e3, e4, e5);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableMapTemplates.java

@@ -1,12 +1,14 @@
 package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableMap.toImmutableMap;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.util.Collections.emptyMap;
+import static java.util.Collections.singletonMap;
 import static java.util.function.Function.identity;
 
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -14,7 +16,6 @@ import com.google.errorprone.refaster.annotation.MayOptionallyUse;
 import com.google.errorprone.refaster.annotation.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.Set;
@@ -40,41 +41,6 @@ final class ImmutableMapTemplates {
     }
   }
 
-  /** Prefer {@link ImmutableMap#of()} over more contrived alternatives. */
-  static final class EmptyImmutableMap<K, V> {
-    @BeforeTemplate
-    ImmutableMap<K, V> before() {
-      return ImmutableMap.<K, V>builder().build();
-    }
-
-    @AfterTemplate
-    ImmutableMap<K, V> after() {
-      return ImmutableMap.of();
-    }
-  }
-
-  /**
-   * Prefer {@link ImmutableMap#of(Object, Object)} over more contrived alternatives and
-   * alternatives that don't communicate the immutability of the resulting map at the type level..
-   */
-  // XXX: One can define variants for more than one key-value pair, but at some point the builder
-  // actually produces nicer code. So it's not clear we should add Refaster templates for those
-  // variants.
-  // XXX: Note that the `singletonMap` rewrite rule is incorrect for nullable elements.
-  static final class PairToImmutableMap<K, V> {
-    @BeforeTemplate
-    Map<K, V> before(K key, V value) {
-      return Refaster.anyOf(
-          ImmutableMap.<K, V>builder().put(key, value).build(),
-          Collections.singletonMap(key, value));
-    }
-
-    @AfterTemplate
-    ImmutableMap<K, V> after(K key, V value) {
-      return ImmutableMap.of(key, value);
-    }
-  }
-
   /** Prefer {@link ImmutableMap#of(Object, Object)} over more contrived alternatives. */
   static final class EntryToImmutableMap<K, V> {
     @BeforeTemplate
@@ -178,7 +144,7 @@ final class ImmutableMapTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableMap<K, V> after(Stream<E> stream) {
       return stream.collect(toImmutableMap(e -> keyFunction(e), e -> valueFunction(e)));
     }
@@ -226,7 +192,7 @@ final class ImmutableMapTemplates {
 
     // XXX: Instead of `Map.Entry::getKey` we could also match `e -> e.getKey()`. But for some
     // reason Refaster doesn't handle that case. This doesn't matter if we roll out use of
-    // `MethodReferenceUsageCheck`. Same observation applies to a lot of other Refaster checks.
+    // `MethodReferenceUsage`. Same observation applies to a lot of other Refaster checks.
     @BeforeTemplate
     @SuppressWarnings("NullAway")
     ImmutableMap<K, V2> before(Map<K, V1> map) {
@@ -242,16 +208,108 @@ final class ImmutableMapTemplates {
     }
   }
 
-  /** Don't unnecessarily copy an {@link ImmutableMap}. */
-  static final class ImmutableMapCopyOfImmutableMap<K, V> {
+  /**
+   * Prefer {@link ImmutableMap#of()} over more contrived alternatives or alternatives that don't
+   * communicate the immutability of the resulting map at the type level.
+   */
+  static final class ImmutableMapOf<K, V> {
     @BeforeTemplate
-    ImmutableMap<K, V> before(ImmutableMap<K, V> map) {
-      return ImmutableMap.copyOf(map);
+    Map<K, V> before() {
+      return Refaster.anyOf(ImmutableMap.<K, V>builder().build(), emptyMap(), Map.of());
     }
 
     @AfterTemplate
-    ImmutableMap<K, V> after(ImmutableMap<K, V> map) {
-      return map;
+    ImmutableMap<K, V> after() {
+      return ImmutableMap.of();
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableMap#of(Object, Object)} over more contrived alternatives or alternatives
+   * that don't communicate the immutability of the resulting map at the type level.
+   */
+  // XXX: Note that the replacement of `Collections#singletonMap` is incorrect for nullable
+  // elements.
+  static final class ImmutableMapOf1<K, V> {
+    @BeforeTemplate
+    Map<K, V> before(K k1, V v1) {
+      return Refaster.anyOf(
+          ImmutableMap.<K, V>builder().put(k1, v1).build(), singletonMap(k1, v1), Map.of(k1, v1));
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(K k1, V v1) {
+      return ImmutableMap.of(k1, v1);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableMap#of(Object, Object, Object, Object)} over alternatives that don't
+   * communicate the immutability of the resulting map at the type level.
+   */
+  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  static final class ImmutableMapOf2<K, V> {
+    @BeforeTemplate
+    Map<K, V> before(K k1, V v1, K k2, V v2) {
+      return Map.of(k1, v1, k2, v2);
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(K k1, V v1, K k2, V v2) {
+      return ImmutableMap.of(k1, v1, k2, v2);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableMap#of(Object, Object, Object, Object, Object, Object)} over
+   * alternatives that don't communicate the immutability of the resulting map at the type level.
+   */
+  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  static final class ImmutableMapOf3<K, V> {
+    @BeforeTemplate
+    Map<K, V> before(K k1, V v1, K k2, V v2, K k3, V v3) {
+      return Map.of(k1, v1, k2, v2, k3, v3);
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(K k1, V v1, K k2, V v2, K k3, V v3) {
+      return ImmutableMap.of(k1, v1, k2, v2, k3, v3);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableMap#of(Object, Object, Object, Object, Object, Object, Object, Object)}
+   * over alternatives that don't communicate the immutability of the resulting map at the type
+   * level.
+   */
+  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  static final class ImmutableMapOf4<K, V> {
+    @BeforeTemplate
+    Map<K, V> before(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
+      return Map.of(k1, v1, k2, v2, k3, v3, k4, v4);
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
+      return ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableMap#of(Object, Object, Object, Object, Object, Object, Object, Object,
+   * Object, Object)} over alternatives that don't communicate the immutability of the resulting map
+   * at the type level.
+   */
+  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  static final class ImmutableMapOf5<K, V> {
+    @BeforeTemplate
+    Map<K, V> before(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
+      return Map.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5);
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
+      return ImmutableMap.of(k1, v1, k2, v2, k3, v3, k4, v4, k5, v5);
     }
   }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableMultisetTemplates.java

@@ -1,12 +1,10 @@
 package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableMultiset.toImmutableMultiset;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 
 import com.google.common.collect.ImmutableMultiset;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -90,28 +88,13 @@ final class ImmutableMultisetTemplates {
   static final class StreamToImmutableMultiset<T> {
     @BeforeTemplate
     ImmutableMultiset<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableMultiset.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableMultiset::copyOf)));
+      return ImmutableMultiset.copyOf(stream.iterator());
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableMultiset<T> after(Stream<T> stream) {
       return stream.collect(toImmutableMultiset());
     }
   }
-
-  /** Don't unnecessarily copy an {@link ImmutableMultiset}. */
-  static final class ImmutableMultisetCopyOfImmutableMultiset<T> {
-    @BeforeTemplate
-    ImmutableMultiset<T> before(ImmutableMultiset<T> multiset) {
-      return ImmutableMultiset.copyOf(multiset);
-    }
-
-    @AfterTemplate
-    ImmutableMultiset<T> after(ImmutableMultiset<T> multiset) {
-      return multiset;
-    }
-  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableSetMultimapTemplates.java

@@ -2,6 +2,7 @@ package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableSetMultimap.flatteningToImmutableSetMultimap;
 import static com.google.common.collect.ImmutableSetMultimap.toImmutableSetMultimap;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 
 import com.google.common.collect.ImmutableSetMultimap;
 import com.google.common.collect.ListMultimap;
@@ -10,7 +11,6 @@ import com.google.common.collect.Multimaps;
 import com.google.common.collect.SetMultimap;
 import com.google.common.collect.SortedSetMultimap;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -138,7 +138,7 @@ final class ImmutableSetMultimapTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableSetMultimap<K, V> after(Stream<E> stream) {
       return stream.collect(toImmutableSetMultimap(e -> keyFunction(e), e -> valueFunction(e)));
     }
@@ -162,7 +162,7 @@ final class ImmutableSetMultimapTemplates {
     @AfterTemplate
     ImmutableSetMultimap<K, V2> after(Multimap<K, V1> multimap) {
       return ImmutableSetMultimap.copyOf(
-          Multimaps.transformValues(multimap, v -> valueTransformation(v)));
+          Multimaps.transformValues(multimap, e -> valueTransformation(e)));
     }
   }
 
@@ -215,17 +215,4 @@ final class ImmutableSetMultimapTemplates {
       return ImmutableSetMultimap.copyOf(Multimaps.transformValues(multimap, transformation));
     }
   }
-
-  /** Don't unnecessarily copy an {@link ImmutableSetMultimap}. */
-  static final class ImmutableSetMultimapCopyOfImmutableSetMultimap<K, V> {
-    @BeforeTemplate
-    ImmutableSetMultimap<K, V> before(ImmutableSetMultimap<K, V> multimap) {
-      return ImmutableSetMultimap.copyOf(multimap);
-    }
-
-    @AfterTemplate
-    ImmutableSetMultimap<K, V> after(ImmutableSetMultimap<K, V> multimap) {
-      return multimap;
-    }
-  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableSetTemplates.java

@@ -1,21 +1,19 @@
 package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
-import static java.util.stream.Collectors.toSet;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.util.Collections.emptySet;
+import static java.util.Collections.singleton;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets.SetView;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.Collections;
 import java.util.Iterator;
 import java.util.Set;
 import java.util.stream.Stream;
@@ -39,37 +37,6 @@ final class ImmutableSetTemplates {
     }
   }
 
-  /** Prefer {@link ImmutableSet#of()} over more contrived alternatives. */
-  static final class EmptyImmutableSet<T> {
-    @BeforeTemplate
-    ImmutableSet<T> before() {
-      return Refaster.anyOf(
-          ImmutableSet.<T>builder().build(), Stream.<T>empty().collect(toImmutableSet()));
-    }
-
-    @AfterTemplate
-    ImmutableSet<T> after() {
-      return ImmutableSet.of();
-    }
-  }
-
-  /**
-   * Prefer {@link ImmutableSet#of(Object)} over alternatives that don't communicate the
-   * immutability of the resulting set at the type level.
-   */
-  // XXX: Note that this rewrite rule is incorrect for nullable elements.
-  static final class SingletonImmutableSet<T> {
-    @BeforeTemplate
-    Set<T> before(T element) {
-      return Collections.singleton(element);
-    }
-
-    @AfterTemplate
-    ImmutableSet<T> after(T element) {
-      return ImmutableSet.of(element);
-    }
-  }
-
   /** Prefer {@link ImmutableSet#copyOf(Iterable)} and variants over more contrived alternatives. */
   static final class IterableToImmutableSet<T> {
     @BeforeTemplate
@@ -105,40 +72,20 @@ final class ImmutableSetTemplates {
   }
 
   /** Prefer {@link ImmutableSet#toImmutableSet()} over less idiomatic alternatives. */
-  // XXX: Once the code base has been sufficiently cleaned up, we might want to also rewrite
-  // `Collectors.toSet(`), with the caveat that it allows mutation (though this cannot be relied
-  // upon) as well as nulls. Another option is to explicitly rewrite those variants to
-  // `Collectors.toSet(HashSet::new)`.
   static final class StreamToImmutableSet<T> {
     @BeforeTemplate
     ImmutableSet<T> before(Stream<T> stream) {
       return Refaster.anyOf(
-          ImmutableSet.copyOf(stream.iterator()),
-          stream.distinct().collect(toImmutableSet()),
-          stream.collect(collectingAndThen(toList(), ImmutableSet::copyOf)),
-          stream.collect(collectingAndThen(toSet(), ImmutableSet::copyOf)));
+          ImmutableSet.copyOf(stream.iterator()), stream.distinct().collect(toImmutableSet()));
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableSet<T> after(Stream<T> stream) {
       return stream.collect(toImmutableSet());
     }
   }
 
-  /** Don't unnecessarily copy an {@link ImmutableSet}. */
-  static final class ImmutableSetCopyOfImmutableSet<T> {
-    @BeforeTemplate
-    ImmutableSet<T> before(ImmutableSet<T> set) {
-      return ImmutableSet.copyOf(set);
-    }
-
-    @AfterTemplate
-    ImmutableSet<T> after(ImmutableSet<T> set) {
-      return set;
-    }
-  }
-
   /** Prefer {@link SetView#immutableCopy()} over the more verbose alternative. */
   static final class ImmutableSetCopyOfSetView<T> {
     @BeforeTemplate
@@ -151,4 +98,115 @@ final class ImmutableSetTemplates {
       return set.immutableCopy();
     }
   }
+
+  /**
+   * Prefer {@link ImmutableSet#of()} over more contrived alternatives or alternatives that don't
+   * communicate the immutability of the resulting set at the type level.
+   */
+  // XXX: The `Stream` variant may be too contrived to warrant inclusion. Review its usage if/when
+  // this and similar Refaster templates are replaced with an Error Prone check.
+  static final class ImmutableSetOf<T> {
+    @BeforeTemplate
+    Set<T> before() {
+      return Refaster.anyOf(
+          ImmutableSet.<T>builder().build(),
+          Stream.<T>empty().collect(toImmutableSet()),
+          emptySet(),
+          Set.of());
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after() {
+      return ImmutableSet.of();
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableSet#of(Object)} over more contrived alternatives or alternatives that
+   * don't communicate the immutability of the resulting set at the type level.
+   */
+  // XXX: Note that the replacement of `Collections#singleton` is incorrect for nullable elements.
+  static final class ImmutableSetOf1<T> {
+    @BeforeTemplate
+    Set<T> before(T e1) {
+      return Refaster.anyOf(ImmutableSet.<T>builder().add(e1).build(), singleton(e1), Set.of(e1));
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T e1) {
+      return ImmutableSet.of(e1);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableSet#of(Object, Object)} over alternatives that don't communicate the
+   * immutability of the resulting set at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableSet.builder()` usages.
+  static final class ImmutableSetOf2<T> {
+    @BeforeTemplate
+    Set<T> before(T e1, T e2) {
+      return Set.of(e1, e2);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T e1, T e2) {
+      return ImmutableSet.of(e1, e2);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableSet#of(Object, Object, Object)} over alternatives that don't communicate
+   * the immutability of the resulting set at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableSet.builder()` usages.
+  static final class ImmutableSetOf3<T> {
+    @BeforeTemplate
+    Set<T> before(T e1, T e2, T e3) {
+      return Set.of(e1, e2, e3);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T e1, T e2, T e3) {
+      return ImmutableSet.of(e1, e2, e3);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableSet#of(Object, Object, Object, Object)} over alternatives that don't
+   * communicate the immutability of the resulting set at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableSet.builder()` usages.
+  static final class ImmutableSetOf4<T> {
+    @BeforeTemplate
+    Set<T> before(T e1, T e2, T e3, T e4) {
+      return Set.of(e1, e2, e3, e4);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4) {
+      return ImmutableSet.of(e1, e2, e3, e4);
+    }
+  }
+
+  /**
+   * Prefer {@link ImmutableSet#of(Object, Object, Object, Object, Object)} over alternatives that
+   * don't communicate the immutability of the resulting set at the type level.
+   */
+  // XXX: Consider writing an Error Prone check which also flags straightforward
+  // `ImmutableSet.builder()` usages.
+  static final class ImmutableSetOf5<T> {
+    @BeforeTemplate
+    Set<T> before(T e1, T e2, T e3, T e4, T e5) {
+      return Set.of(e1, e2, e3, e4, e5);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4, T e5) {
+      return ImmutableSet.of(e1, e2, e3, e4, e5);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableSortedMultisetTemplates.java

@@ -1,14 +1,11 @@
 package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableSortedMultiset.toImmutableSortedMultiset;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.naturalOrder;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
 
-import com.google.common.collect.ImmutableMultiset;
 import com.google.common.collect.ImmutableSortedMultiset;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -93,14 +90,14 @@ final class ImmutableSortedMultisetTemplates {
   // `reverseOrder`.) Worth the hassle?
   static final class IterableToImmutableSortedMultiset<T extends Comparable<? super T>> {
     @BeforeTemplate
-    ImmutableMultiset<T> before(T[] iterable) {
+    ImmutableSortedMultiset<T> before(T[] iterable) {
       return Refaster.anyOf(
           ImmutableSortedMultiset.<T>naturalOrder().add(iterable).build(),
           Arrays.stream(iterable).collect(toImmutableSortedMultiset(naturalOrder())));
     }
 
     @BeforeTemplate
-    ImmutableMultiset<T> before(Iterator<T> iterable) {
+    ImmutableSortedMultiset<T> before(Iterator<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedMultiset.copyOf(naturalOrder(), iterable),
           ImmutableSortedMultiset.<T>naturalOrder().addAll(iterable).build(),
@@ -108,7 +105,7 @@ final class ImmutableSortedMultisetTemplates {
     }
 
     @BeforeTemplate
-    ImmutableMultiset<T> before(Iterable<T> iterable) {
+    ImmutableSortedMultiset<T> before(Iterable<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedMultiset.copyOf(naturalOrder(), iterable),
           ImmutableSortedMultiset.<T>naturalOrder().addAll(iterable).build(),
@@ -134,13 +131,11 @@ final class ImmutableSortedMultisetTemplates {
   static final class StreamToImmutableSortedMultiset<T extends Comparable<? super T>> {
     @BeforeTemplate
     ImmutableSortedMultiset<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableSortedMultiset.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableSortedMultiset::copyOf)));
+      return ImmutableSortedMultiset.copyOf(stream.iterator());
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableSortedMultiset<T> after(Stream<T> stream) {
       return stream.collect(toImmutableSortedMultiset(naturalOrder()));
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableSortedSetTemplates.java

@@ -1,14 +1,11 @@
 package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableSortedSet.toImmutableSortedSet;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.naturalOrder;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
 
-import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSortedSet;
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -91,14 +88,14 @@ final class ImmutableSortedSetTemplates {
   // `reverseOrder`.) Worth the hassle?
   static final class IterableToImmutableSortedSet<T extends Comparable<? super T>> {
     @BeforeTemplate
-    ImmutableSet<T> before(T[] iterable) {
+    ImmutableSortedSet<T> before(T[] iterable) {
       return Refaster.anyOf(
           ImmutableSortedSet.<T>naturalOrder().add(iterable).build(),
           Arrays.stream(iterable).collect(toImmutableSortedSet(naturalOrder())));
     }
 
     @BeforeTemplate
-    ImmutableSet<T> before(Iterator<T> iterable) {
+    ImmutableSortedSet<T> before(Iterator<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedSet.copyOf(naturalOrder(), iterable),
           ImmutableSortedSet.<T>naturalOrder().addAll(iterable).build(),
@@ -106,7 +103,7 @@ final class ImmutableSortedSetTemplates {
     }
 
     @BeforeTemplate
-    ImmutableSet<T> before(Iterable<T> iterable) {
+    ImmutableSortedSet<T> before(Iterable<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedSet.copyOf(naturalOrder(), iterable),
           ImmutableSortedSet.<T>naturalOrder().addAll(iterable).build(),
@@ -134,13 +131,11 @@ final class ImmutableSortedSetTemplates {
   static final class StreamToImmutableSortedSet<T extends Comparable<? super T>> {
     @BeforeTemplate
     ImmutableSortedSet<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableSortedSet.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableSortedSet::copyOf)));
+      return ImmutableSortedSet.copyOf(stream.iterator());
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     ImmutableSortedSet<T> after(Stream<T> stream) {
       return stream.collect(toImmutableSortedSet(naturalOrder()));
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/JUnitTemplates.java

@@ -1,8 +1,8 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.junit.jupiter.params.provider.Arguments.arguments;
 
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.Repeated;
@@ -21,7 +21,7 @@ final class JUnitTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Arguments after(@Repeated T objects) {
       return arguments(objects);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/MapEntryTemplates.java

@@ -1,12 +1,12 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.comparing;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Map.Entry.comparingByKey;
 import static java.util.Map.Entry.comparingByValue;
 
 import com.google.common.collect.Maps;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -51,7 +51,7 @@ final class MapEntryTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<Map.Entry<K, V>> after() {
       return comparingByKey();
     }
@@ -65,7 +65,7 @@ final class MapEntryTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<Map.Entry<K, V>> after(Comparator<? super K> cmp) {
       return comparingByKey(cmp);
     }
@@ -80,7 +80,7 @@ final class MapEntryTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<Map.Entry<K, V>> after() {
       return comparingByValue();
     }
@@ -94,7 +94,7 @@ final class MapEntryTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<Map.Entry<K, V>> after(Comparator<? super V> cmp) {
       return comparingByValue(cmp);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/MockitoTemplates.java

@@ -1,10 +1,10 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
@@ -26,7 +26,7 @@ final class MockitoTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     VerificationMode after() {
       return never();
     }
@@ -43,7 +43,7 @@ final class MockitoTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     T after(T mock) {
       return verify(mock);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/NullTemplates.java

@@ -1,9 +1,9 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Objects.requireNonNullElse;
 
 import com.google.common.base.MoreObjects;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
@@ -24,7 +24,7 @@ final class NullTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     T after(T first, T second) {
       return requireNonNullElse(first, second);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/OptionalTemplates.java

@@ -1,7 +1,8 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -14,6 +15,7 @@ import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 import java.util.stream.Stream;
+import javax.annotation.Nullable;
 
 /** Refaster templates related to expressions dealing with {@link Optional}s. */
 final class OptionalTemplates {
@@ -24,7 +26,7 @@ final class OptionalTemplates {
     // parentheses around the null check, but that's currently not the case. Try to fix that.
     @BeforeTemplate
     @SuppressWarnings("TernaryOperatorOptionalNegativeFiltering" /* Special case. */)
-    Optional<T> before(T object) {
+    Optional<T> before(@Nullable T object) {
       return object == null ? Optional.empty() : Optional.of(object);
     }
 
@@ -91,19 +93,6 @@ final class OptionalTemplates {
     }
   }
 
-  /** Prefer {@link Optional#stream()} over the Guava alternative. */
-  static final class OptionalToStream<T> {
-    @BeforeTemplate
-    Stream<T> before(Optional<T> optional) {
-      return Streams.stream(optional);
-    }
-
-    @AfterTemplate
-    Stream<T> after(Optional<T> optional) {
-      return optional.stream();
-    }
-  }
-
   /**
    * Don't use the ternary operator to extract the first element of a possibly-empty {@link
    * Iterator} as an {@link Optional}.
@@ -115,7 +104,7 @@ final class OptionalTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Optional<T> after(Iterator<T> it) {
       return Streams.stream(it).findFirst();
     }
@@ -124,7 +113,7 @@ final class OptionalTemplates {
   /** Prefer {@link Optional#filter(Predicate)} over usage of the ternary operator. */
   // XXX: This rule may introduce a compilation error: the `test` expression may reference a
   // non-effectively final variable, which is not allowed in the replacement lambda expression.
-  // Maybe our RefasterCheck should test `compilesWithFix`?
+  // Maybe our `Refaster` checker should test `compilesWithFix`?
   abstract static class TernaryOperatorOptionalPositiveFiltering<T> {
     @Placeholder
     abstract boolean test(T value);
@@ -144,7 +133,7 @@ final class OptionalTemplates {
   /** Prefer {@link Optional#filter(Predicate)} over usage of the ternary operator. */
   // XXX: This rule may introduce a compilation error: the `test` expression may reference a
   // non-effectively final variable, which is not allowed in the replacement lambda expression.
-  // Maybe our RefasterCheck should test `compilesWithFix`?
+  // Maybe our `Refaster` checker should test `compilesWithFix`?
   abstract static class TernaryOperatorOptionalNegativeFiltering<T> {
     @Placeholder
     abstract boolean test(T value);
@@ -177,6 +166,11 @@ final class OptionalTemplates {
     }
   }
 
+  /**
+   * Prefer {@link Optional#map} over a {@link Optional#flatMap} which wraps the result of a
+   * transformation in an {@link Optional}; the former operation transforms {@code null} to {@link
+   * Optional#empty()}.
+   */
   abstract static class MapToNullable<T, S> {
     @Placeholder
     abstract S toNullableFunction(@MayOptionallyUse T element);

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ReactorTemplates.java

@@ -1,9 +1,10 @@
 package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.MoreCollectors.toOptional;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static org.assertj.core.api.Assertions.assertThat;
 
 import com.google.common.collect.MoreCollectors;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -142,6 +143,35 @@ final class ReactorTemplates {
     }
   }
 
+  /** Prefer {@link Flux#concatMap(Function)} over more contrived alternatives. */
+  static final class FluxConcatMap<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<T> flux, Function<? super T, ? extends Publisher<? extends S>> function) {
+      return Refaster.anyOf(flux.flatMap(function, 1), flux.flatMapSequential(function, 1));
+    }
+
+    @AfterTemplate
+    Flux<S> after(Flux<T> flux, Function<? super T, ? extends Publisher<? extends S>> function) {
+      return flux.concatMap(function);
+    }
+  }
+
+  /**
+   * Prefer {@link Flux#concatMapIterable(Function)} over {@link Flux#flatMapIterable(Function)}, as
+   * the former has equivalent semantics but a clearer name.
+   */
+  static final class FluxConcatMapIterable<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<T> flux, Function<? super T, ? extends Iterable<? extends S>> function) {
+      return flux.flatMapIterable(function);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Flux<T> flux, Function<? super T, ? extends Iterable<? extends S>> function) {
+      return flux.concatMapIterable(function);
+    }
+  }
+
   /**
    * Don't use {@link Mono#flatMapMany(Function)} to implicitly convert a {@link Mono} to a {@link
    * Flux}.
@@ -161,6 +191,19 @@ final class ReactorTemplates {
     }
   }
 
+  /** Prefer {@link Mono#flux()}} over more contrived alternatives. */
+  static final class MonoFlux<T> {
+    @BeforeTemplate
+    Flux<T> before(Mono<T> mono) {
+      return Flux.concat(mono);
+    }
+
+    @AfterTemplate
+    Flux<T> after(Mono<T> mono) {
+      return mono.flux();
+    }
+  }
+
   /**
    * Prefer a collection using {@link MoreCollectors#toOptional()} over more contrived alternatives.
    */
@@ -175,12 +218,38 @@ final class ReactorTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Mono<Optional<T>> after(Mono<T> mono) {
       return mono.flux().collect(toOptional());
     }
   }
 
+  /** Prefer {@link Mono#cast(Class)} over {@link Mono#map(Function)} with a cast. */
+  static final class MonoCast<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Mono<T> mono) {
+      return mono.map(Refaster.<S>clazz()::cast);
+    }
+
+    @AfterTemplate
+    Mono<S> after(Mono<T> mono) {
+      return mono.cast(Refaster.<S>clazz());
+    }
+  }
+
+  /** Prefer {@link Flux#cast(Class)} over {@link Flux#map(Function)} with a cast. */
+  static final class FluxCast<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<T> flux) {
+      return flux.map(Refaster.<S>clazz()::cast);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Flux<T> flux) {
+      return flux.cast(Refaster.<S>clazz());
+    }
+  }
+
   /** Prefer {@link PublisherProbe#empty()}} over more verbose alternatives. */
   static final class PublisherProbeEmpty<T> {
     @BeforeTemplate
@@ -194,6 +263,32 @@ final class ReactorTemplates {
     }
   }
 
+  /** Prefer {@link Mono#as(Function)} when creating a {@link StepVerifier}. */
+  static final class StepVerifierFromMono<T> {
+    @BeforeTemplate
+    StepVerifier.FirstStep<? extends T> before(Mono<T> mono) {
+      return StepVerifier.create(mono);
+    }
+
+    @AfterTemplate
+    StepVerifier.FirstStep<? extends T> after(Mono<T> mono) {
+      return mono.as(StepVerifier::create);
+    }
+  }
+
+  /** Prefer {@link Flux#as(Function)} when creating a {@link StepVerifier}. */
+  static final class StepVerifierFromFlux<T> {
+    @BeforeTemplate
+    StepVerifier.FirstStep<? extends T> before(Flux<T> flux) {
+      return StepVerifier.create(flux);
+    }
+
+    @AfterTemplate
+    StepVerifier.FirstStep<? extends T> after(Flux<T> flux) {
+      return flux.as(StepVerifier::create);
+    }
+  }
+
   /** Don't unnecessarily call {@link StepVerifier.Step#expectNext(Object[])}. */
   static final class StepVerifierStepExpectNextEmpty<T> {
     @BeforeTemplate
@@ -252,7 +347,9 @@ final class ReactorTemplates {
   static final class StepVerifierLastStepVerifyErrorClass<T extends Throwable> {
     @BeforeTemplate
     Duration before(StepVerifier.LastStep step, Class<T> clazz) {
-      return step.expectError(clazz).verify();
+      return Refaster.anyOf(
+          step.expectError(clazz).verify(),
+          step.verifyErrorSatisfies(t -> assertThat(t).isInstanceOf(clazz)));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJava2AdapterTemplates.java

@@ -18,19 +18,6 @@ import reactor.core.publisher.Mono;
 final class RxJava2AdapterTemplates {
   private RxJava2AdapterTemplates() {}
 
-  /** Remove double conversion of ... */
-  static final class FluxToFlowableToFlux<T> {
-    @BeforeTemplate
-    Flux<T> before(Flux<T> flux) {
-      return RxJava2Adapter.flowableToFlux(RxJava2Adapter.fluxToFlowable(flux));
-    }
-
-    @AfterTemplate
-    Flux<T> after(Flux<T> flux) {
-      return flux;
-    }
-  }
-
   /** Use the fluent API style when using {@link RxJava2Adapter#completableToMono}. */
   static final class CompletableToMono {
     @BeforeTemplate
@@ -54,11 +41,9 @@ final class RxJava2AdapterTemplates {
     @BeforeTemplate
     Publisher<T> before(Flowable<T> flowable) {
       return Refaster.anyOf(
-          Flux.from(flowable),
           flowable.compose(Flux::from),
           flowable.to(Flux::from),
           flowable.as(Flux::from),
-          RxJava2Adapter.flowableToFlux(flowable),
           flowable.compose(RxJava2Adapter::flowableToFlux),
           flowable.to(RxJava2Adapter::flowableToFlux));
     }
@@ -80,7 +65,6 @@ final class RxJava2AdapterTemplates {
           Flowable.fromPublisher(flux),
           flux.transform(Flowable::fromPublisher),
           flux.as(Flowable::fromPublisher),
-          RxJava2Adapter.fluxToFlowable(flux),
           flux.transform(RxJava2Adapter::fluxToFlowable));
     }
 
@@ -153,7 +137,6 @@ final class RxJava2AdapterTemplates {
           Flowable.fromPublisher(mono),
           mono.transform(Flowable::fromPublisher),
           mono.as(Flowable::fromPublisher),
-          RxJava2Adapter.monoToFlowable(mono),
           mono.transform(RxJava2Adapter::monoToFlowable));
     }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJavaCompletableToReactorTemplates.java

@@ -1,506 +0,0 @@
-package tech.picnic.errorprone.refastertemplates;
-
-import static com.google.common.collect.ImmutableList.toImmutableList;
-import static org.assertj.core.api.Assertions.assertThat;
-
-import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
-import com.google.errorprone.refaster.Refaster;
-import com.google.errorprone.refaster.annotation.AfterTemplate;
-import com.google.errorprone.refaster.annotation.BeforeTemplate;
-import com.google.errorprone.refaster.annotation.UseImportPolicy;
-import io.reactivex.Completable;
-import io.reactivex.CompletableSource;
-import io.reactivex.Flowable;
-import io.reactivex.Maybe;
-import io.reactivex.MaybeSource;
-import io.reactivex.Single;
-import io.reactivex.SingleSource;
-import io.reactivex.functions.Action;
-import io.reactivex.functions.Consumer;
-import io.reactivex.functions.Predicate;
-import java.util.concurrent.Callable;
-import java.util.function.Supplier;
-import org.reactivestreams.Publisher;
-import reactor.adapter.rxjava.RxJava2Adapter;
-import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
-import tech.picnic.errorprone.migration.util.RxJavaReactorMigrationUtil;
-
-/** The Refaster templates for the migration of the RxJava Completable type to Reactor */
-final class RxJavaCompletableToReactorTemplates {
-
-  private RxJavaCompletableToReactorTemplates() {}
-
-  static final class CompletableAmb {
-    @BeforeTemplate
-    Completable before(Iterable<? extends Completable> sources) {
-      return Completable.amb(sources);
-    }
-
-    @AfterTemplate
-    @UseImportPolicy(ImportPolicy.IMPORT_CLASS_DIRECTLY)
-    Completable after(Iterable<? extends Completable> sources) {
-      return RxJava2Adapter.monoToCompletable(
-          Mono.firstWithSignal(
-              Streams.stream(sources)
-                  .map(RxJava2Adapter::completableToMono)
-                  .collect(toImmutableList())));
-    }
-  }
-
-  // XXX: public static Completable ambArray(CompletableSource[])
-
-  static final class CompletableComplete {
-    @BeforeTemplate
-    Completable before() {
-      return Completable.complete();
-    }
-
-    @AfterTemplate
-    Completable after() {
-      return RxJava2Adapter.monoToCompletable(Mono.empty());
-    }
-  }
-
-  // XXX: public static Completable concat(Iterable)
-  // XXX: public static Completable concat(Publisher)
-  // XXX: public static Completable concat(Publisher,int)
-  // XXX: public static Completable concatArray(CompletableSource[])
-  // XXX: public static Completable create(CompletableOnSubscribe)
-
-  // XXX: The types of the @Before and @After are not matching
-  static final class CompletableDefer {
-    @BeforeTemplate
-    Completable before(Callable<? extends CompletableSource> supplier) {
-      return Completable.defer(supplier);
-    }
-
-    @AfterTemplate
-    Completable after(Callable<? extends Completable> supplier) {
-      return RxJava2Adapter.monoToCompletable(
-          Mono.defer(
-              () ->
-                  RxJava2Adapter.completableToMono(
-                      RxJavaReactorMigrationUtil.callableAsSupplier(supplier).get())));
-    }
-  }
-
-  static final class CompletableErrorCallable {
-    @BeforeTemplate
-    Completable before(Callable<? extends Throwable> throwable) {
-      return Completable.error(throwable);
-    }
-
-    @AfterTemplate
-    Completable after(Supplier<? extends Throwable> throwable) {
-      return RxJava2Adapter.monoToCompletable(Mono.error(throwable));
-    }
-  }
-
-  static final class CompletableErrorThrowable {
-    @BeforeTemplate
-    Completable before(Throwable throwable) {
-      return Completable.error(throwable);
-    }
-
-    @AfterTemplate
-    Completable after(Throwable throwable) {
-      return RxJava2Adapter.monoToCompletable(Mono.error(throwable));
-    }
-  }
-
-  static final class CompletableFromAction {
-    @BeforeTemplate
-    Completable before(Action action) {
-      return Completable.fromAction(action);
-    }
-
-    @AfterTemplate
-    Completable after(Action action) {
-      return RxJava2Adapter.monoToCompletable(
-          Mono.fromRunnable(RxJavaReactorMigrationUtil.toRunnable(action)));
-    }
-  }
-
-  static final class CompletableFromCallable {
-    @BeforeTemplate
-    Completable before(Callable<?> supplier) {
-      return Completable.fromCallable(supplier);
-    }
-
-    @AfterTemplate
-    Completable after(Callable<?> supplier) {
-      return RxJava2Adapter.monoToCompletable(Mono.fromCallable(supplier));
-    }
-  }
-
-  // XXX: public static Completable fromFuture(Future)
-  // XXX: public static Completable fromMaybe(MaybeSource)
-  // XXX: public static Completable fromObservable(ObservableSource)
-
-  static final class CompletableFromPublisher<T> {
-    @BeforeTemplate
-    Completable before(Publisher<T> source) {
-      return Completable.fromPublisher(source);
-    }
-
-    @AfterTemplate
-    Completable after(Publisher<T> source) {
-      return RxJava2Adapter.monoToCompletable(Mono.from(source));
-    }
-  }
-
-  static final class CompletableFromRunnable {
-    @BeforeTemplate
-    Completable before(Runnable runnable) {
-      return Completable.fromRunnable(runnable);
-    }
-
-    @AfterTemplate
-    Completable after(Runnable runnable) {
-      return RxJava2Adapter.monoToCompletable(Mono.fromRunnable(runnable));
-    }
-  }
-
-  // XXX: public static Completable fromSingle(SingleSource)
-  // XXX: public static Completable merge(Iterable)
-  // XXX: public static Completable merge(Publisher)
-  // XXX: public static Completable merge(Publisher,int)
-  // XXX: public static Completable mergeArray(CompletableSource[])
-  // XXX: public static Completable mergeArrayDelayError(CompletableSource[])
-  // XXX: public static Completable mergeDelayError(Iterable)
-  // XXX: public static Completable mergeDelayError(Publisher)
-  // XXX: public static Completable mergeDelayError(Publisher,int)
-  // XXX: public static Completable never()
-  // XXX: public static Completable timer(long,TimeUnit)
-  // XXX: public static Completable timer(long,TimeUnit,Scheduler)
-  // XXX: public static Completable unsafeCreate(CompletableSource)
-  // XXX: public static Completable using(Callable,Function,Consumer)
-  // XXX: public static Completable using(Callable,Function,Consumer,boolean)
-
-  static final class CompletableWrap {
-    @BeforeTemplate
-    Completable before(Completable source) {
-      return Completable.wrap(source);
-    }
-
-    @AfterTemplate
-    Completable after(Completable source) {
-      return source;
-    }
-  }
-
-  // XXX: public final Completable ambWith(CompletableSource)
-
-  static final class CompletableAndThenCompletable {
-    @BeforeTemplate
-    Completable before(Completable completable, CompletableSource source) {
-      return completable.andThen(source);
-    }
-
-    @AfterTemplate
-    Completable after(Completable completable, CompletableSource source) {
-      return RxJava2Adapter.monoToCompletable(
-          RxJava2Adapter.completableToMono(completable)
-              .then(RxJava2Adapter.completableToMono(Completable.wrap(source))));
-    }
-  }
-
-  static final class CompletableAndThenMaybe<T> {
-    @BeforeTemplate
-    Maybe<T> before(Completable completable, MaybeSource<T> source) {
-      return completable.andThen(source);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Completable completable, MaybeSource<T> source) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.completableToMono(completable)
-              .then(RxJava2Adapter.maybeToMono(Maybe.wrap(source))));
-    }
-  }
-
-  // XXX: public final Observable andThen(ObservableSource)
-
-  static final class CompletableAndThenPublisher<T> {
-    @BeforeTemplate
-    Flowable<T> before(Completable completable, Publisher<T> source) {
-      return completable.andThen(source);
-    }
-
-    @AfterTemplate
-    Flowable<T> after(Completable completable, Publisher<T> source) {
-      return RxJava2Adapter.fluxToFlowable(
-          RxJava2Adapter.completableToMono(completable).thenMany(source));
-    }
-  }
-
-  static final class CompletableAndThenSingle<T> {
-    @BeforeTemplate
-    Single<T> before(Completable completable, SingleSource<T> source) {
-      return completable.andThen(source);
-    }
-
-    @AfterTemplate
-    Single<T> after(Completable completable, SingleSource<T> source) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.completableToMono(completable)
-              .then(RxJava2Adapter.singleToMono(Single.wrap(source))));
-    }
-  }
-
-  // XXX: public final Object as(CompletableConverter)
-
-  static final class CompletableBlockingAwait {
-    @BeforeTemplate
-    void before(Completable completable) {
-      completable.blockingAwait();
-    }
-
-    @AfterTemplate
-    void after(Completable completable) {
-      RxJava2Adapter.completableToMono(completable).block();
-    }
-  }
-
-  // XXX: public final boolean blockingAwait(long,TimeUnit)
-  // XXX: public final Throwable blockingGet()
-  // XXX: public final Throwable blockingGet(long,TimeUnit)
-  // XXX: public final Completable cache()
-  // XXX: public final Completable compose(CompletableTransformer)
-  // XXX: public final Completable concatWith(CompletableSource)
-  // XXX: public final Completable delay(long,TimeUnit)
-  // XXX: public final Completable delay(long,TimeUnit,Scheduler)
-  // XXX: public final Completable delay(long,TimeUnit,Scheduler,boolean)
-  // XXX: public final Completable delaySubscription(long,TimeUnit)
-  // XXX: public final Completable delaySubscription(long,TimeUnit,Scheduler)
-  // XXX: public final Completable doAfterTerminate(Action)
-  // XXX: public final Completable doFinally(Action)
-  // XXX: public final Completable doOnComplete(Action)
-  // XXX: public final Completable doOnDispose(Action)
-  // XXX: public final Completable doOnError(Consumer)
-  // XXX: public final Completable doOnEvent(Consumer)
-  // XXX: public final Completable doOnSubscribe(Consumer)
-
-  static final class CompletableDoOnError {
-    @BeforeTemplate
-    Completable before(Completable completable, Consumer<? super Throwable> consumer) {
-      return completable.doOnError(consumer);
-    }
-
-    @AfterTemplate
-    Completable after(Completable completable, Consumer<? super Throwable> consumer) {
-      return RxJava2Adapter.monoToCompletable(
-          RxJava2Adapter.completableToMono(completable)
-              .doOnError(RxJavaReactorMigrationUtil.toJdkConsumer(consumer)));
-    }
-  }
-
-  // XXX: public final Completable doOnTerminate(Action)
-  // XXX: public final Completable hide()
-  // XXX: public final Completable lift(CompletableOperator)
-  // XXX: public final Single materialize()
-  // XXX: public final Completable mergeWith(CompletableSource)
-  // XXX: public final Completable observeOn(Scheduler)
-
-  // XXX: Verify whether this is the correct equivalent.
-  static final class CompletableOnErrorComplete {
-    Completable before(Completable completable) {
-      return completable.onErrorComplete();
-    }
-
-    Completable after(Completable completable) {
-      return RxJava2Adapter.monoToCompletable(
-          RxJava2Adapter.completableToMono(completable).onErrorStop());
-    }
-  }
-
-  static final class CompletableOnErrorCompletePredicate {
-    Completable before(Completable completable, Predicate<? super Throwable> predicate) {
-      return completable.onErrorComplete(predicate);
-    }
-
-    Completable after(Completable completable, Predicate<? super Throwable> predicate) {
-      return RxJava2Adapter.monoToCompletable(
-          RxJava2Adapter.completableToMono(completable)
-              .onErrorResume(
-                  RxJavaReactorMigrationUtil.toJdkPredicate(predicate), t -> Mono.empty()));
-    }
-  }
-
-  // XXX: public final Completable onErrorComplete(Predicate)
-  // XXX: public final Completable onErrorResumeNext(Function)
-  // XXX: public final Completable onTerminateDetach()
-  // XXX: public final Completable repeat()
-  // XXX: public final Completable repeat(long)
-  // XXX: public final Completable repeatUntil(BooleanSupplier)
-  // XXX: public final Completable repeatWhen(Function)
-  // XXX: public final Completable retry()
-  // XXX: public final Completable retry(BiPredicate)
-  // XXX: public final Completable retry(long)
-  // XXX: public final Completable retry(long,Predicate)
-  // XXX: public final Completable retry(Predicate)
-  // XXX: public final Completable retryWhen(Function)
-  // XXX: public final Completable startWith(CompletableSource)
-  // XXX: public final Observable startWith(Observable)
-  // XXX: public final Flowable startWith(Publisher)
-  // XXX: public final Disposable subscribe()
-  // XXX: public final Disposable subscribe(Action)
-  // XXX: public final Disposable subscribe(Action,Consumer)
-  // XXX: public final void subscribe(CompletableObserver)
-  // XXX: public final Completable subscribeOn(Scheduler)
-  // XXX: public final CompletableObserver subscribeWith(CompletableObserver)
-  // XXX: public final Completable takeUntil(CompletableSource)
-  // XXX: public final Completable timeout(long,TimeUnit)
-  // XXX: public final Completable timeout(long,TimeUnit,CompletableSource)
-  // XXX: public final Completable timeout(long,TimeUnit,Scheduler)
-  // XXX: public final Completable timeout(long,TimeUnit,Scheduler,CompletableSource)
-  // XXX: public final Object to(Function)
-
-  static final class CompletableToFlowable {
-    @BeforeTemplate
-    Flowable<Void> before(Completable completable) {
-      return completable.toFlowable();
-    }
-
-    @AfterTemplate
-    Flowable<Void> after(Completable completable) {
-      return RxJava2Adapter.fluxToFlowable(RxJava2Adapter.completableToMono(completable).flux());
-    }
-  }
-
-  // XXX: Requires investigation. Should not be Void...
-  static final class CompletableToMaybe {
-    @BeforeTemplate
-    Maybe<Void> before(Completable completable) {
-      return completable.toMaybe();
-    }
-
-    @AfterTemplate
-    Maybe<Void> after(Completable completable) {
-      return RxJava2Adapter.monoToMaybe(RxJava2Adapter.completableToMono(completable));
-    }
-  }
-
-  // XXX: public final Observable toObservable()
-  // XXX: public final Single toSingle(Callable)
-  // XXX: public final Single toSingleDefault(Object)
-  // XXX: public final Completable unsubscribeOn(Scheduler)
-
-  static final class CompletableTestAssertResult {
-    @BeforeTemplate
-    void before(Completable completable) throws InterruptedException {
-      Refaster.anyOf(
-          completable.test().await().assertResult(),
-          completable.test().assertResult(),
-          completable.test().await());
-    }
-
-    @AfterTemplate
-    void after(Completable completable) {
-      RxJava2Adapter.completableToMono(completable).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class CompletableTestAssertComplete {
-    @BeforeTemplate
-    void before(Completable completable) throws InterruptedException {
-      Refaster.anyOf(
-          completable.test().await().assertComplete(), completable.test().assertComplete());
-    }
-
-    @AfterTemplate
-    void after(Completable completable) {
-      RxJava2Adapter.completableToMono(completable).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class CompletableTestAssertErrorClass {
-    @BeforeTemplate
-    void before(Completable completable, Class<? extends Throwable> errorClass)
-        throws InterruptedException {
-      Refaster.anyOf(
-          completable.test().await().assertError(errorClass),
-          completable.test().assertError(errorClass));
-    }
-
-    @AfterTemplate
-    void after(Completable completable, Class<? extends Throwable> errorClass) {
-      RxJava2Adapter.completableToMono(completable)
-          .as(StepVerifier::create)
-          .verifyError(errorClass);
-    }
-  }
-
-  static final class CompletableTestAssertNoErrors {
-    @BeforeTemplate
-    void before(Completable completable) throws InterruptedException {
-      completable.test().await().assertNoErrors();
-    }
-
-    @AfterTemplate
-    void after(Completable completable) {
-      RxJava2Adapter.completableToMono(completable).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class CompletableTestAssertValueCount {
-    @BeforeTemplate
-    void before(Completable completable, int count) throws InterruptedException {
-      completable.test().await().assertValueCount(count);
-    }
-
-    @AfterTemplate
-    void after(Completable completable, int count) {
-      RxJava2Adapter.completableToMono(completable)
-          .as(StepVerifier::create)
-          .expectNextCount(count)
-          .verifyComplete();
-    }
-  }
-
-  static final class CompletableTestAssertFailure {
-    @BeforeTemplate
-    void before(Completable completable, Class<? extends Throwable> error)
-        throws InterruptedException {
-      completable.test().await().assertFailure(error);
-    }
-
-    @AfterTemplate
-    void after(Completable completable, Class<? extends Throwable> error) {
-      RxJava2Adapter.completableToMono(completable).as(StepVerifier::create).verifyError(error);
-    }
-  }
-
-  static final class CompletableTestAssertNoValues {
-    @BeforeTemplate
-    void before(Completable completable) throws InterruptedException {
-      completable.test().await().assertNoValues();
-    }
-
-    @AfterTemplate
-    void after(Completable completable) {
-      RxJava2Adapter.completableToMono(completable).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class CompletableTestAssertFailureAndMessage {
-    @BeforeTemplate
-    void before(Completable completable, Class<? extends Throwable> error, String message)
-        throws InterruptedException {
-      completable.test().await().assertFailureAndMessage(error, message);
-    }
-
-    @AfterTemplate
-    void after(Completable completable, Class<? extends Throwable> error, String message) {
-      RxJava2Adapter.completableToMono(completable)
-          .as(StepVerifier::create)
-          .expectErrorSatisfies(
-              t -> assertThat(t).isInstanceOf(error).hasMessageContaining(message))
-          .verify();
-    }
-  }
-
-  // XXX: public final TestObserver test(boolean)
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJavaMaybeToReactorTemplates.java

@@ -1,959 +0,0 @@
-package tech.picnic.errorprone.refastertemplates;
-
-import static com.google.common.collect.ImmutableList.toImmutableList;
-import static org.assertj.core.api.Assertions.assertThat;
-
-import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
-import com.google.errorprone.refaster.Refaster;
-import com.google.errorprone.refaster.annotation.AfterTemplate;
-import com.google.errorprone.refaster.annotation.BeforeTemplate;
-import com.google.errorprone.refaster.annotation.MayOptionallyUse;
-import com.google.errorprone.refaster.annotation.Placeholder;
-import com.google.errorprone.refaster.annotation.Repeated;
-import com.google.errorprone.refaster.annotation.UseImportPolicy;
-import io.reactivex.Completable;
-import io.reactivex.CompletableSource;
-import io.reactivex.Flowable;
-import io.reactivex.Maybe;
-import io.reactivex.MaybeSource;
-import io.reactivex.Observable;
-import io.reactivex.Single;
-import io.reactivex.SingleSource;
-import io.reactivex.disposables.Disposable;
-import io.reactivex.functions.Action;
-import io.reactivex.functions.BiFunction;
-import io.reactivex.functions.Consumer;
-import io.reactivex.functions.Function;
-import io.reactivex.functions.Predicate;
-import java.util.Arrays;
-import java.util.concurrent.Callable;
-import java.util.concurrent.CompletableFuture;
-import org.reactivestreams.Publisher;
-import reactor.adapter.rxjava.RxJava2Adapter;
-import reactor.core.publisher.Flux;
-import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
-import tech.picnic.errorprone.migration.util.RxJavaReactorMigrationUtil;
-
-/** The Refaster templates for the migration of the RxJava Maybe type to Reactor */
-final class RxJavaMaybeToReactorTemplates {
-  private RxJavaMaybeToReactorTemplates() {}
-
-  static final class MaybeAmb<T> {
-    @BeforeTemplate
-    Maybe<T> before(Iterable<? extends Maybe<? extends T>> iterable) {
-      return Maybe.amb(iterable);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Iterable<? extends Maybe<? extends T>> iterable) {
-      return RxJava2Adapter.monoToMaybe(
-          Mono.firstWithSignal(
-              Streams.stream(iterable)
-                  .map(RxJava2Adapter::maybeToMono)
-                  .collect(toImmutableList())));
-    }
-  }
-
-  // XXX: public static Maybe ambArray(MaybeSource... sources)
-  // XXX: public static Flowable concat(Iterable)
-  // XXX: public static Flowable concat(MaybeSource,MaybeSource)
-  // XXX: public static Flowable concat(MaybeSource,MaybeSource,MaybeSource)
-  // XXX: public static Flowable concat(MaybeSource,MaybeSource,MaybeSource,MaybeSource)
-  // XXX: public static Flowable concat(Publisher)
-  // XXX: public static Flowable concat(Publisher,int)
-
-  // XXX: How to make this conversion correct? Turned off test for now.
-  static final class MaybeConcatArray<T> {
-    @BeforeTemplate
-    Flowable<T> before(@Repeated Maybe<T> sources) {
-      return Maybe.concatArray(Refaster.asVarargs(sources));
-    }
-
-    @AfterTemplate
-    Flowable<T> after(@Repeated Maybe<T> sources) {
-      return RxJava2Adapter.fluxToFlowable(
-          Flux.concat(
-              Arrays.stream(Refaster.asVarargs(sources))
-                  .map(RxJava2Adapter::maybeToMono)
-                  .collect(toImmutableList())));
-    }
-  }
-
-  // XXX: public static Flowable concatArrayDelayError(MaybeSource[])
-  // XXX: public static Flowable concatArrayEager(MaybeSource[])
-  // XXX: public static Flowable concatDelayError(Iterable)
-  // XXX: public static Flowable concatDelayError(Publisher)
-  // XXX: public static Flowable concatEager(Iterable)
-  // XXX: public static Flowable concatEager(Publisher)
-  // XXX: public static Maybe create(MaybeOnSubscribe)
-
-  /// XXX: Add test
-  abstract static class MaybeDeferFirst<T> {
-    @Placeholder
-    abstract Maybe<T> maybeProducer();
-
-    @BeforeTemplate
-    Maybe<T> before() {
-      return Maybe.defer(() -> maybeProducer());
-    }
-
-    @AfterTemplate
-    Maybe<T> after() {
-      return RxJava2Adapter.monoToMaybe(
-          Mono.defer(() -> RxJava2Adapter.maybeToMono(maybeProducer())));
-    }
-  }
-
-  abstract static class MaybeDefer<T> {
-    @Placeholder
-    abstract Maybe<T> maybeProducer();
-
-    @BeforeTemplate
-    Mono<T> before() {
-      return Maybe.defer(() -> maybeProducer()).as(RxJava2Adapter::maybeToMono);
-    }
-
-    @AfterTemplate
-    Mono<T> after() {
-      return Mono.defer(() -> RxJava2Adapter.maybeToMono(maybeProducer()));
-    }
-  }
-
-  static final class MaybeEmpty<T> {
-    @BeforeTemplate
-    Maybe<T> before() {
-      return Maybe.empty();
-    }
-
-    @AfterTemplate
-    Maybe<T> after() {
-      return RxJava2Adapter.monoToMaybe(Mono.empty());
-    }
-  }
-
-  static final class MaybeErrorCallable<T> {
-    @BeforeTemplate
-    Maybe<T> before(Callable<? extends Throwable> throwable) {
-      return Maybe.error(throwable);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Callable<? extends Throwable> throwable) {
-      return RxJava2Adapter.monoToMaybe(
-          Mono.error(RxJavaReactorMigrationUtil.callableAsSupplier(throwable)));
-    }
-  }
-
-  static final class MaybeErrorThrowable<T> {
-    @BeforeTemplate
-    Maybe<T> before(Throwable throwable) {
-      return Maybe.error(throwable);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Throwable throwable) {
-      return RxJava2Adapter.monoToMaybe(Mono.error(throwable));
-    }
-  }
-
-  static final class MaybeFromAction<T> {
-    @BeforeTemplate
-    Maybe<T> before(Action action) {
-      return Maybe.fromAction(action);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Action action) {
-      return RxJava2Adapter.monoToMaybe(
-          Mono.fromRunnable(RxJavaReactorMigrationUtil.toRunnable(action)));
-    }
-  }
-
-  static final class MaybeFromCallable<T> {
-    @BeforeTemplate
-    Maybe<T> before(Callable<? extends T> callable) {
-      return Maybe.fromCallable(callable);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Callable<? extends T> callable) {
-      return RxJava2Adapter.monoToMaybe(
-          Mono.fromSupplier(RxJavaReactorMigrationUtil.callableAsSupplier(callable)));
-    }
-  }
-
-  // XXX: public static Maybe fromCompletable(CompletableSource)
-
-  // XXX: Also handle `Future`s that don't extend `CompletableFuture`.
-  static final class MaybeFromFuture<T> {
-    @BeforeTemplate
-    Maybe<T> before(CompletableFuture<? extends T> future) {
-      return Maybe.fromFuture(future);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(CompletableFuture<? extends T> future) {
-      return RxJava2Adapter.monoToMaybe(Mono.fromFuture(future));
-    }
-  }
-
-  // XXX: public static Maybe fromFuture(Future,long,TimeUnit)
-
-  static final class MaybeFromRunnable<T> {
-    @BeforeTemplate
-    Maybe<T> before(Runnable runnable) {
-      return Maybe.fromRunnable(runnable);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Runnable runnable) {
-      return RxJava2Adapter.monoToMaybe(Mono.fromRunnable(runnable));
-    }
-  }
-
-  static final class MaybeFromSingle<T> {
-    @BeforeTemplate
-    Maybe<T> before(SingleSource<T> source) {
-      return Maybe.fromSingle(source);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(SingleSource<T> source) {
-      return RxJava2Adapter.monoToMaybe(
-          Mono.from(RxJava2Adapter.singleToMono(Single.wrap(source))));
-    }
-  }
-
-  static final class MaybeJust<T> {
-    @BeforeTemplate
-    Maybe<T> before(T item) {
-      return Maybe.just(item);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(T item) {
-      return RxJava2Adapter.monoToMaybe(Mono.just(item));
-    }
-  }
-
-  // XXX: public static Flowable merge(Iterable)
-  // XXX: public static Maybe merge(MaybeSource)
-  // XXX: public static Flowable merge(MaybeSource,MaybeSource)
-  // XXX: public static Flowable merge(MaybeSource,MaybeSource,MaybeSource)
-  // XXX: public static Flowable merge(MaybeSource,MaybeSource,MaybeSource,MaybeSource)
-  // XXX: public static Flowable merge(Publisher)
-  // XXX: public static Flowable merge(Publisher,int)
-  // XXX: public static Flowable mergeArray(MaybeSource[])
-  // XXX: public static Flowable mergeArrayDelayError(MaybeSource[])
-  // XXX: public static Flowable mergeDelayError(Iterable)
-  // XXX: public static Flowable mergeDelayError(MaybeSource,MaybeSource)
-  // XXX: public static Flowable mergeDelayError(MaybeSource,MaybeSource,MaybeSource)
-  // XXX: public static Flowable mergeDelayError(MaybeSource,MaybeSource,MaybeSource,MaybeSource)
-  // XXX: public static Flowable mergeDelayError(Publisher)
-  // XXX: public static Flowable mergeDelayError(Publisher,int)
-  // XXX: public static Maybe never()
-  // XXX: public static Single sequenceEqual(MaybeSource,MaybeSource)
-  // XXX: public static Single sequenceEqual(MaybeSource,MaybeSource,BiPredicate)
-  // XXX: public static Maybe timer(long,TimeUnit)
-  // XXX: public static Maybe timer(long,TimeUnit,Scheduler)
-  // XXX: public static Maybe unsafeCreate(MaybeSource)
-  // XXX: public static Maybe using(Callable,Function,Consumer)
-  // XXX: public static Maybe using(Callable,Function,Consumer,boolean)
-
-  static final class MaybeWrap<T> {
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe) {
-      return Maybe.wrap(maybe);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe) {
-      return maybe;
-    }
-  }
-
-  // XXX: public static Maybe zip(Iterable,Function)
-  // XXX: public static Maybe zip(MaybeSource,MaybeSource,BiFunction)
-  // XXX: public static Maybe zip(MaybeSource,MaybeSource,MaybeSource,Function3)
-  // XXX: public static Maybe zip(MaybeSource,MaybeSource,MaybeSource,MaybeSource,Function4)
-  // XXX: public static Maybe
-  // zip(MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,Function5)
-  // XXX: public static Maybe
-  // zip(MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,Function6)
-  // XXX: public static Maybe
-  // zip(MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,Function7)
-  // XXX: public static Maybe
-  // zip(MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,Function8)
-  // XXX: public static Maybe
-  // zip(MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,MaybeSource,Function9)
-  // XXX: public static Maybe zipArray(Function,MaybeSource[])
-
-  static final class MaybeAmbWith<T> {
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe, Maybe<? extends T> otherMaybe) {
-      return maybe.ambWith(otherMaybe);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe, Maybe<? extends T> otherMaybe) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe).or(RxJava2Adapter.maybeToMono(otherMaybe)));
-    }
-  }
-
-  // XXX: public final Object as(MaybeConverter)
-
-  static final class MaybeBlockingGet<T> {
-    @BeforeTemplate
-    Object before(Maybe<T> maybe) {
-      return maybe.blockingGet();
-    }
-
-    @AfterTemplate
-    Object after(Maybe<T> maybe) {
-      return RxJava2Adapter.maybeToMono(maybe).block();
-    }
-  }
-
-  // XXX: public final Object blockingGet(Object)
-  // XXX: public final Maybe cache()
-
-  static final class MaybeCast<T> {
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe) {
-      return maybe.cast(Refaster.<T>clazz());
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe) {
-      return maybe;
-    }
-  }
-
-  // XXX: public final Maybe compose(MaybeTransformer)
-  // XXX: public final Maybe concatMap(Function)
-  // XXX: public final Flowable concatWith(MaybeSource)
-  // XXX: public final Single contains(Object)
-  // XXX: public final Single count()
-
-  static final class MaybeDefaultIfEmpty<T> {
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe, T item) {
-      return maybe.defaultIfEmpty(item);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe, T item) {
-      return RxJava2Adapter.monoToMaybe(RxJava2Adapter.maybeToMono(maybe).defaultIfEmpty(item));
-    }
-  }
-
-  // XXX: public final Maybe delay(long,TimeUnit)
-  // XXX: public final Maybe delay(long,TimeUnit,Scheduler)
-  // XXX: public final Maybe delay(Publisher)
-  // XXX: public final Maybe delaySubscription(long,TimeUnit)
-  // XXX: public final Maybe delaySubscription(long,TimeUnit,Scheduler)
-  // XXX: public final Maybe delaySubscription(Publisher)
-  // XXX: public final Maybe doAfterSuccess(Consumer)
-  // XXX: public final Maybe doAfterTerminate(Action)
-  // XXX: public final Maybe doFinally(Action)
-  // XXX: public final Maybe doOnComplete(Action)
-  // XXX: public final Maybe doOnDispose(Action)
-
-  static final class MaybeDoOnError<T> {
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe, Consumer<? super Throwable> consumer) {
-      return maybe.doOnError(consumer);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe, Consumer<? super Throwable> consumer) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .doOnError(RxJavaReactorMigrationUtil.toJdkConsumer(consumer)));
-    }
-  }
-
-  // XXX: public final Maybe doOnEvent(BiConsumer)
-  // XXX: public final Maybe doOnSubscribe(Consumer)
-
-  static final class MaybeDoOnSuccess<T> {
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe, Consumer<T> consumer) {
-      return maybe.doOnSuccess(consumer);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe, Consumer<T> consumer) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .doOnSuccess(RxJavaReactorMigrationUtil.toJdkConsumer(consumer)));
-    }
-  }
-
-  // XXX: public final Maybe doOnTerminate(Action)
-
-  static final class MaybeFilter<T> {
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe, Predicate<T> predicate) {
-      return maybe.filter(predicate);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe, Predicate<T> predicate) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .filter(RxJavaReactorMigrationUtil.toJdkPredicate(predicate)));
-    }
-  }
-
-  static final class MaybeFlatMapFunction<
-      I, T extends I, O, X extends O, M extends MaybeSource<X>> {
-    @BeforeTemplate
-    Maybe<O> before(
-        Maybe<T> maybe, Function<? super T, ? extends MaybeSource<? extends O>> function) {
-      return maybe.flatMap(function);
-    }
-
-    @AfterTemplate
-    @UseImportPolicy(ImportPolicy.IMPORT_CLASS_DIRECTLY)
-    Maybe<O> after(Maybe<T> maybe, Function<I, M> function) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .flatMap(
-                  v ->
-                      RxJava2Adapter.maybeToMono(
-                          Maybe.wrap(
-                              RxJavaReactorMigrationUtil.<I, M>toJdkFunction(function).apply(v)))));
-    }
-  }
-
-  // XXX: There is no link to an original public method for this, but it is important.
-  abstract static class MaybeFlatMapLambda<S, T> {
-    @Placeholder
-    abstract Maybe<T> toMaybeFunction(@MayOptionallyUse S element);
-
-    @BeforeTemplate
-    Maybe<T> before(Maybe<S> maybe) {
-      return maybe.flatMap(v -> toMaybeFunction(v));
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<S> maybe) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .flatMap(z -> toMaybeFunction(z).as(RxJava2Adapter::maybeToMono)));
-    }
-  }
-
-  // XXX: public final Maybe flatMap(Function,BiFunction)
-  // XXX: public final Maybe flatMap(Function,Function,Callable)
-
-  // XXX: Add test
-  static final class MaybeFlatMapCompletable<T, R extends CompletableSource> {
-    @BeforeTemplate
-    Completable before(Maybe<T> maybe, Function<T, R> function) {
-      return maybe.flatMapCompletable(function);
-    }
-
-    @AfterTemplate
-    Completable after(Maybe<T> maybe, Function<T, R> function) {
-      return RxJava2Adapter.monoToCompletable(
-          RxJava2Adapter.maybeToMono(maybe)
-              .flatMap(
-                  y ->
-                      RxJava2Adapter.completableToMono(
-                          Completable.wrap(
-                              RxJavaReactorMigrationUtil.toJdkFunction((Function<T, R>) function)
-                                  .apply(y))))
-              .then());
-    }
-  }
-
-  // XXX: public final Observable flatMapObservable(Function)
-
-  static final class MaybeFlatMapPublisher<T, O extends T, R extends Publisher<O>> {
-    @BeforeTemplate
-    Flowable<O> before(
-        Maybe<T> maybe, Function<? super T, ? extends Publisher<? extends O>> function) {
-      return maybe.flatMapPublisher(function);
-    }
-
-    @AfterTemplate
-    Flowable<O> after(Maybe<T> maybe, Function<T, R> function) {
-      return RxJava2Adapter.monoToFlowable(
-          RxJava2Adapter.maybeToMono(maybe)
-              .flatMap(
-                  y ->
-                      Mono.from(
-                          RxJavaReactorMigrationUtil.<T, R>toJdkFunction(function).apply(y))));
-    }
-  }
-
-  static final class MaybeFlatMapSingle<T, O extends T, R extends SingleSource<O>> {
-    @BeforeTemplate
-    Single<O> before(
-        Maybe<T> maybe, Function<? super T, ? extends SingleSource<? extends O>> function) {
-      return maybe.flatMapSingle(function);
-    }
-
-    @AfterTemplate
-    Single<O> after(Maybe<T> maybe, Function<T, R> function) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.maybeToMono(maybe)
-              .flatMap(
-                  y ->
-                      RxJava2Adapter.singleToMono(
-                          Single.wrap(
-                              RxJavaReactorMigrationUtil.<T, R>toJdkFunction(function).apply(y)))));
-    }
-  }
-
-  // XXX: Improve the @AfterTemplate to not have a cast
-  @SuppressWarnings("unchecked")
-  static final class MaybeFlatMapSingleElement<T, O> {
-    @BeforeTemplate
-    Maybe<O> before(
-        Maybe<T> maybe, Function<? super T, ? extends SingleSource<? extends O>> function) {
-      return maybe.flatMapSingleElement(function);
-    }
-
-    @AfterTemplate
-    Maybe<O> after(
-        Maybe<T> maybe, Function<? super T, ? extends SingleSource<? extends O>> function) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .flatMap(
-                  e ->
-                      RxJava2Adapter.singleToMono(
-                          Single.wrap(
-                              RxJavaReactorMigrationUtil.toJdkFunction(
-                                      (Function<T, SingleSource<O>>) function)
-                                  .apply(e)))));
-    }
-  }
-
-  // XXX: public final Flowable flattenAsFlowable(Function)
-  // XXX: public final Observable flattenAsObservable(Function)
-  // XXX: public final Maybe hide()
-
-  static final class MaybeIgnoreElement<T> {
-    @BeforeTemplate
-    Completable before(Maybe<T> maybe) {
-      return maybe.ignoreElement();
-    }
-
-    @AfterTemplate
-    Completable after(Maybe<T> maybe) {
-      return RxJava2Adapter.monoToCompletable(RxJava2Adapter.maybeToMono(maybe).then());
-    }
-  }
-
-  // XXX: Add test
-  static final class MaybeIsEmpty<T> {
-    @BeforeTemplate
-    Single<Boolean> before(Maybe<T> maybe) {
-      return maybe.isEmpty();
-    }
-
-    @AfterTemplate
-    Single<Boolean> after(Maybe<T> maybe) {
-      return RxJava2Adapter.monoToSingle(RxJava2Adapter.maybeToMono(maybe).hasElement());
-    }
-  }
-
-  // XXX: public final Maybe lift(MaybeOperator)
-  // XXX: public final Maybe map(Function)
-
-  static final class MaybeMap<T, R> {
-    @BeforeTemplate
-    Maybe<R> before(Maybe<T> maybe, Function<T, R> mapper) {
-      return maybe.map(mapper);
-    }
-
-    @AfterTemplate
-    Maybe<R> after(Maybe<T> maybe, Function<T, R> mapper) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe).map(RxJavaReactorMigrationUtil.toJdkFunction(mapper)));
-    }
-  }
-
-  // XXX: public final Single materialize()
-  // XXX: public final Flowable mergeWith(MaybeSource)
-  // XXX: public final Maybe observeOn(Scheduler)
-  // XXX: public final Maybe ofType(Class)
-  // XXX: public final Maybe onErrorComplete()
-  // XXX: public final Maybe onErrorComplete(Predicate)
-  // XXX: public final Maybe onErrorResumeNext(Function)
-  // XXX: public final Maybe onErrorResumeNext(MaybeSource)
-  // XXX: public final Maybe onErrorReturn(Function)
-
-  abstract static class MaybeOnErrorReturn<T, R> {
-    @Placeholder
-    abstract T placeholder(@MayOptionallyUse Throwable throwable);
-
-    @BeforeTemplate
-    Maybe<T> before(Maybe<T> maybe) {
-      return maybe.onErrorReturn(t -> placeholder(t));
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Maybe<T> maybe) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe).onErrorResume(t -> Mono.just(placeholder(t))));
-    }
-  }
-
-  // XXX: public final Maybe onErrorReturnItem(Object)
-  // XXX: public final Maybe onExceptionResumeNext(MaybeSource)
-  // XXX: public final Maybe onTerminateDetach()
-  // XXX: public final Flowable repeat()
-  // XXX: public final Flowable repeat(long)
-  // XXX: public final Flowable repeatUntil(BooleanSupplier)
-  // XXX: public final Flowable repeatWhen(Function)
-  // XXX: public final Maybe retry()
-  // XXX: public final Maybe retry(BiPredicate)
-  // XXX: public final Maybe retry(long)
-  // XXX: public final Maybe retry(long,Predicate)
-  // XXX: public final Maybe retry(Predicate)
-  // XXX: public final Maybe retryUntil(BooleanSupplier)
-  // XXX: public final Maybe retryWhen(Function)
-
-  // XXX: Add test
-  static final class MaybeSubscribe<T> {
-    @BeforeTemplate
-    Disposable before(Maybe<T> maybe) {
-      return maybe.subscribe();
-    }
-
-    @AfterTemplate
-    reactor.core.Disposable after(Maybe<T> maybe) {
-      return RxJava2Adapter.maybeToMono(maybe).subscribe();
-    }
-  }
-
-  // XXX: Add test
-  static final class MaybeSubscribeConsumer<T> {
-    @BeforeTemplate
-    Disposable before(Maybe<T> maybe, Consumer<? super T> consumer) {
-      return maybe.subscribe(consumer);
-    }
-
-    @AfterTemplate
-    reactor.core.Disposable after(Maybe<T> maybe, Consumer<? super T> consumer) {
-      return RxJava2Adapter.maybeToMono(maybe)
-          .subscribe(RxJavaReactorMigrationUtil.toJdkConsumer(consumer));
-    }
-  }
-
-  // XXX: Add test
-  static final class MaybeSubscribeTwoConsumers<T> {
-    @BeforeTemplate
-    Disposable before(
-        Maybe<T> maybe, Consumer<? super T> consumer1, Consumer<? super Throwable> consumer2) {
-      return maybe.subscribe(consumer1, consumer2);
-    }
-
-    @AfterTemplate
-    reactor.core.Disposable after(
-        Maybe<T> maybe, Consumer<? super T> consumer1, Consumer<? super Throwable> consumer2) {
-      return RxJava2Adapter.maybeToMono(maybe)
-          .subscribe(
-              RxJavaReactorMigrationUtil.toJdkConsumer(consumer1),
-              RxJavaReactorMigrationUtil.toJdkConsumer(consumer2));
-    }
-  }
-
-  // XXX: Add test
-  static final class MaybeSubscribeTwoConsumersWithAction<T> {
-    @BeforeTemplate
-    Disposable before(
-        Maybe<T> maybe,
-        Consumer<? super T> consumer1,
-        Consumer<? super Throwable> consumer2,
-        Action action) {
-      return maybe.subscribe(consumer1, consumer2, action);
-    }
-
-    @AfterTemplate
-    reactor.core.Disposable after(
-        Maybe<T> maybe,
-        Consumer<? super T> consumer1,
-        Consumer<? super Throwable> consumer2,
-        Action action) {
-      return RxJava2Adapter.maybeToMono(maybe)
-          .subscribe(
-              RxJavaReactorMigrationUtil.toJdkConsumer(consumer1),
-              RxJavaReactorMigrationUtil.toJdkConsumer(consumer2),
-              RxJavaReactorMigrationUtil.toRunnable(action));
-    }
-  }
-
-  // XXX: public final void subscribe(MaybeObserver)
-  // XXX: public final Maybe subscribeOn(Scheduler)
-  // XXX: public final MaybeObserver subscribeWith(MaybeObserver)
-
-  // XXX: Add test
-  static final class MaybeSourceSwitchIfEmpty<S, T extends S> {
-    @BeforeTemplate
-    Maybe<S> before(Maybe<S> maybe, MaybeSource<T> maybeSource) {
-      return maybe.switchIfEmpty(maybeSource);
-    }
-
-    @AfterTemplate
-    Maybe<S> after(Maybe<S> maybe, MaybeSource<T> maybeSource) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .switchIfEmpty(RxJava2Adapter.maybeToMono(Maybe.wrap(maybeSource))));
-    }
-  }
-
-  static final class MaybeSwitchIfEmpty<S, T extends S> {
-    @BeforeTemplate
-    Single<S> before(Maybe<S> maybe, SingleSource<T> single) {
-      return maybe.switchIfEmpty(single);
-    }
-
-    @AfterTemplate
-    Single<S> after(Maybe<S> maybe, SingleSource<T> single) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.maybeToMono(maybe)
-              .switchIfEmpty(RxJava2Adapter.singleToMono(Single.wrap(single))));
-    }
-  }
-
-  // XXX: public final Maybe takeUntil(MaybeSource)
-  // XXX: public final Maybe takeUntil(Publisher)
-  // XXX: public final Maybe timeout(long,TimeUnit)
-  // XXX: public final Maybe timeout(long,TimeUnit,MaybeSource)
-  // XXX: public final Maybe timeout(long,TimeUnit,Scheduler)
-  // XXX: public final Maybe timeout(long,TimeUnit,Scheduler,MaybeSource)
-  // XXX: public final Maybe timeout(MaybeSource)
-  // XXX: public final Maybe timeout(MaybeSource,MaybeSource)
-  // XXX: public final Maybe timeout(Publisher)
-  // XXX: public final Maybe timeout(Publisher,MaybeSource)
-  // XXX: public final Object to(Function)
-
-  static final class MaybeToFlowable<T> {
-    @BeforeTemplate
-    Flowable<T> before(Maybe<T> maybe) {
-      return maybe.toFlowable();
-    }
-
-    @AfterTemplate
-    Flowable<T> after(Maybe<T> maybe) {
-      return RxJava2Adapter.fluxToFlowable(RxJava2Adapter.maybeToMono(maybe).flux());
-    }
-  }
-
-  static final class MaybeToObservable<T> {
-    @BeforeTemplate
-    Observable<T> before(Maybe<T> maybe) {
-      return maybe.toObservable();
-    }
-
-    @AfterTemplate
-    Observable<T> after(Maybe<T> maybe) {
-      return RxJava2Adapter.fluxToObservable(RxJava2Adapter.maybeToMono(maybe).flux());
-    }
-  }
-
-  // XXX: Add test
-  static final class MaybeToSingle<T> {
-    @BeforeTemplate
-    Single<T> before(Maybe<T> maybe) {
-      return maybe.toSingle();
-    }
-
-    @AfterTemplate
-    Single<T> after(Maybe<T> maybe) {
-      return RxJava2Adapter.monoToSingle(RxJava2Adapter.maybeToMono(maybe).single());
-    }
-  }
-
-  // XXX: public final Single toSingle(Object)
-  // XXX: public final Maybe unsubscribeOn(Scheduler)
-
-  // XXX: Add test
-  static final class MaybeZipWith<T, R, U> {
-    @BeforeTemplate
-    Maybe<R> before(
-        Maybe<T> maybe,
-        MaybeSource<U> source,
-        BiFunction<? super T, ? super U, ? extends R> biFunction) {
-      return maybe.zipWith(source, biFunction);
-    }
-
-    @AfterTemplate
-    Maybe<R> after(
-        Maybe<T> maybe,
-        MaybeSource<U> source,
-        BiFunction<? super T, ? super U, ? extends R> biFunction) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.maybeToMono(maybe)
-              .zipWith(
-                  RxJava2Adapter.maybeToMono(Maybe.wrap(source)),
-                  RxJavaReactorMigrationUtil.toJdkBiFunction(biFunction)));
-    }
-  }
-
-  @SuppressWarnings("unchecked")
-  static final class MaybeTestAssertResultItem<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe, T item) throws InterruptedException {
-      Refaster.anyOf(
-          maybe.test().await().assertResult(item),
-          maybe.test().await().assertResult(item).assertComplete(),
-          maybe.test().await().assertComplete().assertResult(item),
-          maybe.test().await().assertValue(item),
-          maybe.test().await().assertValue(item).assertComplete(),
-          maybe.test().await().assertComplete().assertValue(item),
-          // XXX: Move this to correct method
-          maybe.test().await().assertValues(item));
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe, T item) {
-      RxJava2Adapter.maybeToMono(maybe).as(StepVerifier::create).expectNext(item).verifyComplete();
-    }
-  }
-
-  @SuppressWarnings("unchecked")
-  static final class MaybeTestAssertResult<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe) throws InterruptedException {
-      maybe.test().await().assertResult();
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe) {
-      RxJava2Adapter.maybeToMono(maybe).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class MaybeTestAssertValue<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe, Predicate<T> predicate) throws InterruptedException {
-      Refaster.anyOf(
-          maybe.test().await().assertValue(predicate),
-          maybe.test().await().assertValue(predicate).assertComplete(),
-          maybe.test().await().assertValue(predicate).assertNoErrors().assertComplete(),
-          maybe.test().await().assertComplete().assertValue(predicate));
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe, Predicate<T> predicate) {
-      RxJava2Adapter.maybeToMono(maybe)
-          .as(StepVerifier::create)
-          .expectNextMatches(RxJavaReactorMigrationUtil.toJdkPredicate(predicate))
-          .verifyComplete();
-    }
-  }
-
-  static final class MaybeTestAssertComplete<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe) throws InterruptedException {
-      maybe.test().await().assertComplete();
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe) {
-      RxJava2Adapter.maybeToMono(maybe).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class MaybeTestAssertErrorClass<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe, Class<? extends Throwable> errorClass) throws InterruptedException {
-      maybe.test().await().assertError(errorClass);
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe, Class<? extends Throwable> errorClass) {
-      RxJava2Adapter.maybeToMono(maybe).as(StepVerifier::create).verifyError(errorClass);
-    }
-  }
-
-  static final class MaybeTestAssertNoErrors<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe) throws InterruptedException {
-      maybe.test().await().assertNoErrors();
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe) {
-      RxJava2Adapter.maybeToMono(maybe).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class MaybeTestAssertValueCount<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe, int count) throws InterruptedException {
-      maybe.test().await().assertValueCount(count);
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe, int count) {
-      RxJava2Adapter.maybeToMono(maybe)
-          .as(StepVerifier::create)
-          .expectNextCount(count)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("unchecked")
-  static final class MaybeTestAssertFailure<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe, Class<? extends Throwable> error) throws InterruptedException {
-      maybe.test().await().assertFailure(error);
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe, Class<? extends Throwable> error) {
-      RxJava2Adapter.maybeToMono(maybe).as(StepVerifier::create).verifyError(error);
-    }
-  }
-
-  // XXX: Add test
-  static final class MaybeTestAssertNoValues<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe) throws InterruptedException {
-      Refaster.anyOf(
-          maybe.test().await().assertNoValues(),
-          maybe.test().assertNoValues(),
-          maybe.test().assertNoValues().assertComplete(),
-          maybe.test().await().assertNoValues().assertComplete(),
-          maybe.test().await().assertComplete().assertNoValues());
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe) {
-      RxJava2Adapter.maybeToMono(maybe).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  // XXX: Add test
-  // XXX: This introduces AssertJ dependency
-  @SuppressWarnings("unchecked")
-  static final class MaybeTestAssertFailureAndMessage<T> {
-    @BeforeTemplate
-    void before(Maybe<T> maybe, Class<? extends Throwable> error, String message)
-        throws InterruptedException {
-      maybe.test().await().assertFailureAndMessage(error, message);
-    }
-
-    @AfterTemplate
-    void after(Maybe<T> maybe, Class<? extends Throwable> error, String message) {
-      RxJava2Adapter.maybeToMono(maybe)
-          .as(StepVerifier::create)
-          .expectErrorSatisfies(
-              t -> assertThat(t).isInstanceOf(error).hasMessageContaining(message))
-          .verify();
-    }
-  }
-
-  // XXX: public final TestObserver test(boolean)
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJavaObservableToReactorTemplates.java

@@ -1,927 +0,0 @@
-package tech.picnic.errorprone.refastertemplates;
-
-import static com.google.common.collect.ImmutableList.toImmutableList;
-import static org.assertj.core.api.Assertions.assertThat;
-
-import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
-import com.google.errorprone.refaster.Refaster;
-import com.google.errorprone.refaster.annotation.AfterTemplate;
-import com.google.errorprone.refaster.annotation.BeforeTemplate;
-import com.google.errorprone.refaster.annotation.Repeated;
-import com.google.errorprone.refaster.annotation.UseImportPolicy;
-import io.reactivex.BackpressureStrategy;
-import io.reactivex.Completable;
-import io.reactivex.Flowable;
-import io.reactivex.Maybe;
-import io.reactivex.MaybeSource;
-import io.reactivex.Observable;
-import io.reactivex.ObservableSource;
-import io.reactivex.functions.Function;
-import io.reactivex.functions.Predicate;
-import java.util.concurrent.Callable;
-import org.reactivestreams.Publisher;
-import reactor.adapter.rxjava.RxJava2Adapter;
-import reactor.core.publisher.Flux;
-import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
-import tech.picnic.errorprone.migration.util.RxJavaReactorMigrationUtil;
-
-/** The Refaster templates for the migration of the RxJava Observable type to Reactor */
-final class RxJavaObservableToReactorTemplates {
-
-  private RxJavaObservableToReactorTemplates() {}
-
-  static final class ObservableAmb<T> {
-    @BeforeTemplate
-    Observable<T> before(Iterable<? extends Observable<T>> sources) {
-      return Observable.amb(sources);
-    }
-
-    @AfterTemplate
-    Observable<T> after(Iterable<? extends Observable<T>> sources) {
-      return RxJava2Adapter.fluxToObservable(
-          Flux.<T>firstWithSignal(
-              Streams.stream(sources)
-                  .map(e -> e.toFlowable(BackpressureStrategy.BUFFER))
-                  .map(RxJava2Adapter::flowableToFlux)
-                  .collect(toImmutableList())));
-    }
-  }
-
-  // XXX: public static Observable ambArray(ObservableSource[])
-  // XXX: public static int bufferSize()
-  // XXX: public static Observable combineLatest(Function,int,ObservableSource[])
-  // XXX: public static Observable combineLatest(Iterable,Function)
-  // XXX: public static Observable combineLatest(Iterable,Function,int)
-  // XXX: public static Observable combineLatest(ObservableSource[],Function)
-  // XXX: public static Observable combineLatest(ObservableSource[],Function,int)
-  // XXX: public static Observable combineLatest(ObservableSource,ObservableSource,BiFunction)
-  // XXX: public static Observable
-  // combineLatest(ObservableSource,ObservableSource,ObservableSource,Function3)
-  // XXX: public static Observable
-  // combineLatest(ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function4)
-  // XXX: public static Observable
-  // combineLatest(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function5)
-  // XXX: public static Observable
-  // combineLatest(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function6)
-  // XXX: public static Observable
-  // combineLatest(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function7)
-  // XXX: public static Observable
-  // combineLatest(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function8)
-  // XXX: public static Observable
-  // combineLatest(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function9)
-  // XXX: public static Observable combineLatestDelayError(Function,int,ObservableSource[])
-  // XXX: public static Observable combineLatestDelayError(Iterable,Function)
-  // XXX: public static Observable combineLatestDelayError(Iterable,Function,int)
-  // XXX: public static Observable combineLatestDelayError(ObservableSource[],Function)
-  // XXX: public static Observable combineLatestDelayError(ObservableSource[],Function,int)
-  // XXX: public static Observable concat(Iterable)
-  // XXX: public static Observable concat(ObservableSource)
-  // XXX: public static Observable concat(ObservableSource,int)
-  // XXX: public static Observable concat(ObservableSource,ObservableSource)
-  // XXX: public static Observable concat(ObservableSource,ObservableSource,ObservableSource)
-  // XXX: public static Observable
-  // concat(ObservableSource,ObservableSource,ObservableSource,ObservableSource)
-  // XXX: public static Observable concatArray(ObservableSource[])
-  // XXX: public static Observable concatArrayDelayError(ObservableSource[])
-  // XXX: public static Observable concatArrayEager(int,int,ObservableSource[])
-  // XXX: public static Observable concatArrayEager(ObservableSource[])
-  // XXX: public static Observable concatArrayEagerDelayError(int,int,ObservableSource[])
-  // XXX: public static Observable concatArrayEagerDelayError(ObservableSource[])
-  // XXX: public static Observable concatDelayError(Iterable)
-  // XXX: public static Observable concatDelayError(ObservableSource)
-  // XXX: public static Observable concatDelayError(ObservableSource,int,boolean)
-  // XXX: public static Observable concatEager(Iterable)
-  // XXX: public static Observable concatEager(Iterable,int,int)
-  // XXX: public static Observable concatEager(ObservableSource)
-  // XXX: public static Observable concatEager(ObservableSource,int,int)
-  // XXX: public static Observable create(ObservableOnSubscribe)
-  // XXX: public static Observable defer(Callable)
-
-  static final class ObservableEmpty<T> {
-    @BeforeTemplate
-    Observable<T> before() {
-      return Observable.empty();
-    }
-
-    @AfterTemplate
-    Observable<T> after() {
-      return RxJava2Adapter.fluxToObservable(Flux.empty());
-    }
-  }
-
-  // XXX: public static Observable error(Callable)
-  // XXX: public static Observable error(Throwable)
-  // XXX: public static Observable fromArray(Object[])
-
-  static final class ObservableFromCallable<T> {
-    @BeforeTemplate
-    Observable<? extends T> before(Callable<? extends T> callable) {
-      return Observable.fromCallable(callable);
-    }
-
-    @AfterTemplate
-    Observable<? extends T> after(Callable<? extends T> callable) {
-      return RxJava2Adapter.fluxToObservable(
-          Mono.fromSupplier(RxJavaReactorMigrationUtil.callableAsSupplier(callable)).flux());
-    }
-  }
-
-  // XXX: public static Observable fromFuture(Future)
-  // XXX: public static Observable fromFuture(Future,long,TimeUnit)
-  // XXX: public static Observable fromFuture(Future,long,TimeUnit,Scheduler)
-  // XXX: public static Observable fromFuture(Future,Scheduler)
-  // XXX: public static Observable fromIterable(Iterable)
-
-  static final class ObservableFromPublisher<T> {
-    @BeforeTemplate
-    Observable<T> before(Publisher<? extends T> source) {
-      return Observable.fromPublisher(source);
-    }
-
-    @AfterTemplate
-    Observable<T> after(Publisher<? extends T> source) {
-      return RxJava2Adapter.fluxToObservable(Flux.from(source));
-    }
-  }
-
-  // XXX: public static Observable generate(Callable,BiConsumer)
-  // XXX: public static Observable generate(Callable,BiConsumer,Consumer)
-  // XXX: public static Observable generate(Callable,BiFunction)
-  // XXX: public static Observable generate(Callable,BiFunction,Consumer)
-  // XXX: public static Observable generate(Consumer)
-  // XXX: public static Observable interval(long,long,TimeUnit)
-  // XXX: public static Observable interval(long,long,TimeUnit,Scheduler)
-  // XXX: public static Observable interval(long,TimeUnit)
-  // XXX: public static Observable interval(long,TimeUnit,Scheduler)
-  // XXX: public static Observable intervalRange(long,long,long,long,TimeUnit)
-  // XXX: public static Observable intervalRange(long,long,long,long,TimeUnit,Scheduler)
-
-  static final class ObservableJust<T> {
-    @BeforeTemplate
-    Observable<T> before(T t) {
-      return Observable.just(t);
-    }
-
-    @AfterTemplate
-    Observable<T> after(T t) {
-      return RxJava2Adapter.fluxToObservable(Flux.just(t));
-    }
-  }
-
-  static final class ObservableJustTwo<T> {
-    @BeforeTemplate
-    Observable<T> before(T t, T t2) {
-      return Observable.just(t, t2);
-    }
-
-    @AfterTemplate
-    Observable<T> after(T t, T t2) {
-      return RxJava2Adapter.fluxToObservable(Flux.just(t, t2));
-    }
-  }
-
-  static final class ObservableJustThree<T> {
-    @BeforeTemplate
-    Observable<T> before(T t, T t2, T t3) {
-      return Observable.just(t, t2, t3);
-    }
-
-    @AfterTemplate
-    Observable<T> after(T t, T t2, T t3) {
-      return RxJava2Adapter.fluxToObservable(Flux.just(t, t2, t3));
-    }
-  }
-
-  // XXX: public static Observable just(Object,Object,Object,Object)
-  // XXX: public static Observable just(Object,Object,Object,Object,Object)
-  // XXX: public static Observable just(Object,Object,Object,Object,Object,Object)
-  // XXX: public static Observable just(Object,Object,Object,Object,Object,Object,Object)
-  // XXX: public static Observable just(Object,Object,Object,Object,Object,Object,Object,Object)
-  // XXX: public static Observable
-  // just(Object,Object,Object,Object,Object,Object,Object,Object,Object)
-  // XXX: public static Observable
-  // just(Object,Object,Object,Object,Object,Object,Object,Object,Object,Object)
-  // XXX: public static Observable merge(Iterable)
-  // XXX: public static Observable merge(Iterable,int)
-  // XXX: public static Observable merge(Iterable,int,int)
-  // XXX: public static Observable merge(ObservableSource)
-  // XXX: public static Observable merge(ObservableSource,int)
-  // XXX: public static Observable merge(ObservableSource,ObservableSource)
-  // XXX: public static Observable merge(ObservableSource,ObservableSource,ObservableSource)
-  // XXX: public static Observable
-  // merge(ObservableSource,ObservableSource,ObservableSource,ObservableSource)
-  // XXX: public static Observable mergeArray(int,int,ObservableSource[])
-  // XXX: public static Observable mergeArray(ObservableSource[])
-  // XXX: public static Observable mergeArrayDelayError(int,int,ObservableSource[])
-  // XXX: public static Observable mergeArrayDelayError(ObservableSource[])
-  // XXX: public static Observable mergeDelayError(Iterable)
-  // XXX: public static Observable mergeDelayError(Iterable,int)
-  // XXX: public static Observable mergeDelayError(Iterable,int,int)
-  // XXX: public static Observable mergeDelayError(ObservableSource)
-  // XXX: public static Observable mergeDelayError(ObservableSource,int)
-  // XXX: public static Observable mergeDelayError(ObservableSource,ObservableSource)
-  // XXX: public static Observable
-  // mergeDelayError(ObservableSource,ObservableSource,ObservableSource)
-  // XXX: public static Observable
-  // mergeDelayError(ObservableSource,ObservableSource,ObservableSource,ObservableSource)
-  // XXX: public static Observable never()
-  // XXX: public static Observable range(int,int)
-  // XXX: public static Observable rangeLong(long,long)
-  // XXX: public static Single sequenceEqual(ObservableSource,ObservableSource)
-  // XXX: public static Single sequenceEqual(ObservableSource,ObservableSource,BiPredicate)
-  // XXX: public static Single sequenceEqual(ObservableSource,ObservableSource,BiPredicate,int)
-  // XXX: public static Single sequenceEqual(ObservableSource,ObservableSource,int)
-  // XXX: public static Observable switchOnNext(ObservableSource)
-  // XXX: public static Observable switchOnNext(ObservableSource,int)
-  // XXX: public static Observable switchOnNextDelayError(ObservableSource)
-  // XXX: public static Observable switchOnNextDelayError(ObservableSource,int)
-  // XXX: public static Observable timer(long,TimeUnit)
-  // XXX: public static Observable timer(long,TimeUnit,Scheduler)
-  // XXX: public static Observable unsafeCreate(ObservableSource)
-  // XXX: public static Observable using(Callable,Function,Consumer)
-  // XXX: public static Observable using(Callable,Function,Consumer,boolean)
-  // XXX: public static Observable wrap(ObservableSource)
-  // XXX: public static Observable zip(Iterable,Function)
-  // XXX: public static Observable zip(ObservableSource,Function)
-  // XXX: public static Observable zip(ObservableSource,ObservableSource,BiFunction)
-  // XXX: public static Observable zip(ObservableSource,ObservableSource,BiFunction,boolean)
-  // XXX: public static Observable zip(ObservableSource,ObservableSource,BiFunction,boolean,int)
-  // XXX: public static Observable zip(ObservableSource,ObservableSource,ObservableSource,Function3)
-  // XXX: public static Observable
-  // zip(ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function4)
-  // XXX: public static Observable
-  // zip(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function5)
-  // XXX: public static Observable
-  // zip(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function6)
-  // XXX: public static Observable
-  // zip(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function7)
-  // XXX: public static Observable
-  // zip(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function8)
-  // XXX: public static Observable
-  // zip(ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function9)
-  // XXX: public static Observable zipArray(Function,boolean,int,ObservableSource[])
-  // XXX: public static Observable zipIterable(Iterable,Function,boolean,int)
-  // XXX: public final Single all(Predicate)
-  // XXX: public final Observable ambWith(ObservableSource)
-  // XXX: public final Single any(Predicate)
-  // XXX: public final Object as(ObservableConverter)
-  // XXX: public final Object blockingFirst()
-  // XXX: public final Object blockingFirst(Object)
-  // XXX: public final void blockingForEach(Consumer)
-  // XXX: public final Iterable blockingIterable()
-  // XXX: public final Iterable blockingIterable(int)
-  // XXX: public final Object blockingLast()
-  // XXX: public final Object blockingLast(Object)
-  // XXX: public final Iterable blockingLatest()
-  // XXX: public final Iterable blockingMostRecent(Object)
-  // XXX: public final Iterable blockingNext()
-  // XXX: public final Object blockingSingle()
-  // XXX: public final Object blockingSingle(Object)
-  // XXX: public final void blockingSubscribe()
-  // XXX: public final void blockingSubscribe(Consumer)
-  // XXX: public final void blockingSubscribe(Consumer,Consumer)
-  // XXX: public final void blockingSubscribe(Consumer,Consumer,Action)
-  // XXX: public final void blockingSubscribe(Observer)
-  // XXX: public final Observable buffer(Callable)
-  // XXX: public final Observable buffer(Callable,Callable)
-  // XXX: public final Observable buffer(int)
-  // XXX: public final Observable buffer(int,Callable)
-  // XXX: public final Observable buffer(int,int)
-  // XXX: public final Observable buffer(int,int,Callable)
-  // XXX: public final Observable buffer(long,long,TimeUnit)
-  // XXX: public final Observable buffer(long,long,TimeUnit,Scheduler)
-  // XXX: public final Observable buffer(long,long,TimeUnit,Scheduler,Callable)
-  // XXX: public final Observable buffer(long,TimeUnit)
-  // XXX: public final Observable buffer(long,TimeUnit,int)
-  // XXX: public final Observable buffer(long,TimeUnit,Scheduler)
-  // XXX: public final Observable buffer(long,TimeUnit,Scheduler,int)
-  // XXX: public final Observable buffer(long,TimeUnit,Scheduler,int,Callable,boolean)
-  // XXX: public final Observable buffer(ObservableSource)
-  // XXX: public final Observable buffer(ObservableSource,Callable)
-  // XXX: public final Observable buffer(ObservableSource,Function)
-  // XXX: public final Observable buffer(ObservableSource,Function,Callable)
-  // XXX: public final Observable buffer(ObservableSource,int)
-  // XXX: public final Observable cache()
-  // XXX: public final Observable cacheWithInitialCapacity(int)
-  // XXX: public final Observable cast(Class)
-  // XXX: public final Single collect(Callable,BiConsumer)
-  // XXX: public final Single collectInto(Object,BiConsumer)
-  // XXX: public final Observable compose(ObservableTransformer)
-  // XXX: public final Observable concatMap(Function)
-  // XXX: public final Observable concatMap(Function,int)
-  // XXX: public final Completable concatMapCompletable(Function)
-  // XXX: public final Completable concatMapCompletable(Function,int)
-  // XXX: public final Completable concatMapCompletableDelayError(Function)
-  // XXX: public final Completable concatMapCompletableDelayError(Function,boolean)
-  // XXX: public final Completable concatMapCompletableDelayError(Function,boolean,int)
-  // XXX: public final Observable concatMapDelayError(Function)
-  // XXX: public final Observable concatMapDelayError(Function,int,boolean)
-  // XXX: public final Observable concatMapEager(Function)
-  // XXX: public final Observable concatMapEager(Function,int,int)
-  // XXX: public final Observable concatMapEagerDelayError(Function,boolean)
-  // XXX: public final Observable concatMapEagerDelayError(Function,int,int,boolean)
-  // XXX: public final Observable concatMapIterable(Function)
-  // XXX: public final Observable concatMapIterable(Function,int)
-  // XXX: public final Observable concatMapMaybe(Function)
-  // XXX: public final Observable concatMapMaybe(Function,int)
-  // XXX: public final Observable concatMapMaybeDelayError(Function)
-  // XXX: public final Observable concatMapMaybeDelayError(Function,boolean)
-  // XXX: public final Observable concatMapMaybeDelayError(Function,boolean,int)
-  // XXX: public final Observable concatMapSingle(Function)
-  // XXX: public final Observable concatMapSingle(Function,int)
-  // XXX: public final Observable concatMapSingleDelayError(Function)
-  // XXX: public final Observable concatMapSingleDelayError(Function,boolean)
-  // XXX: public final Observable concatMapSingleDelayError(Function,boolean,int)
-  // XXX: public final Observable concatWith(CompletableSource)
-  // XXX: public final Observable concatWith(MaybeSource)
-  // XXX: public final Observable concatWith(ObservableSource)
-  // XXX: public final Observable concatWith(SingleSource)
-  // XXX: public final Single contains(Object)
-  // XXX: public final Single count()
-  // XXX: public final Observable debounce(Function)
-  // XXX: public final Observable debounce(long,TimeUnit)
-  // XXX: public final Observable debounce(long,TimeUnit,Scheduler)
-  // XXX: public final Observable defaultIfEmpty(Object)
-  // XXX: public final Observable delay(Function)
-  // XXX: public final Observable delay(long,TimeUnit)
-  // XXX: public final Observable delay(long,TimeUnit,boolean)
-  // XXX: public final Observable delay(long,TimeUnit,Scheduler)
-  // XXX: public final Observable delay(long,TimeUnit,Scheduler,boolean)
-  // XXX: public final Observable delay(ObservableSource,Function)
-  // XXX: public final Observable delaySubscription(long,TimeUnit)
-  // XXX: public final Observable delaySubscription(long,TimeUnit,Scheduler)
-  // XXX: public final Observable delaySubscription(ObservableSource)
-  // XXX: public final Observable dematerialize()
-  // XXX: public final Observable dematerialize(Function)
-  // XXX: public final Observable distinct()
-  // XXX: public final Observable distinct(Function)
-  // XXX: public final Observable distinct(Function,Callable)
-  // XXX: public final Observable distinctUntilChanged()
-  // XXX: public final Observable distinctUntilChanged(BiPredicate)
-  // XXX: public final Observable distinctUntilChanged(Function)
-  // XXX: public final Observable doAfterNext(Consumer)
-  // XXX: public final Observable doAfterTerminate(Action)
-  // XXX: public final Observable doFinally(Action)
-  // XXX: public final Observable doOnComplete(Action)
-  // XXX: public final Observable doOnDispose(Action)
-  // XXX: public final Observable doOnEach(Consumer)
-  // XXX: public final Observable doOnEach(Observer)
-  // XXX: public final Observable doOnError(Consumer)
-  // XXX: public final Observable doOnLifecycle(Consumer,Action)
-  // XXX: public final Observable doOnNext(Consumer)
-  // XXX: public final Observable doOnSubscribe(Consumer)
-  // XXX: public final Observable doOnTerminate(Action)
-  // XXX: public final Maybe elementAt(long)
-  // XXX: public final Single elementAt(long,Object)
-  // XXX: public final Single elementAtOrError(long)
-
-  // XXX: Default BackPressureStrategy.BUFFER is set.
-  static final class ObservableFilter<T> {
-    @BeforeTemplate
-    Observable<T> before(Observable<T> observable, Predicate<T> predicate) {
-      return observable.filter(predicate);
-    }
-
-    @AfterTemplate
-    Observable<T> after(Observable<T> observable, Predicate<T> predicate) {
-      return RxJava2Adapter.fluxToObservable(
-          RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-              .filter(RxJavaReactorMigrationUtil.toJdkPredicate(predicate)));
-    }
-  }
-
-  // XXX: public final Single first(Object)
-
-  // XXX: Default BUFFER is chosen here.
-  static final class MaybeFirstElement<T> {
-    @BeforeTemplate
-    Maybe<T> before(Observable<T> observable) {
-      return observable.firstElement();
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Observable<T> observable) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER).next());
-    }
-  }
-
-  // XXX: public final Single firstOrError()
-  // XXX: public final Observable flatMap(Function)
-
-  // XXX: Add test
-  // XXX: Default BUFFER is set here.
-  static final class ObservableFlatMap<I, T extends I, O, P extends ObservableSource<O>> {
-    @BeforeTemplate
-    Observable<O> before(
-        Observable<T> observable,
-        Function<? super T, ? extends ObservableSource<? extends O>> function) {
-      return observable.flatMap(function);
-    }
-
-    @UseImportPolicy(ImportPolicy.IMPORT_CLASS_DIRECTLY)
-    @AfterTemplate
-    Observable<O> after(Observable<T> observable, Function<I, P> function) {
-      return RxJava2Adapter.fluxToObservable(
-          RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-              .flatMap(
-                  z ->
-                      RxJava2Adapter.observableToFlux(
-                          Observable.wrap(
-                              RxJavaReactorMigrationUtil.<I, P>toJdkFunction(function).apply(z)),
-                          BackpressureStrategy.BUFFER)));
-    }
-  }
-
-  // XXX: public final Observable flatMap(Function,BiFunction)
-  // XXX: public final Observable flatMap(Function,BiFunction,boolean)
-  // XXX: public final Observable flatMap(Function,BiFunction,boolean,int)
-  // XXX: public final Observable flatMap(Function,BiFunction,boolean,int,int)
-  // XXX: public final Observable flatMap(Function,BiFunction,int)
-  // XXX: public final Observable flatMap(Function,boolean)
-  // XXX: public final Observable flatMap(Function,boolean,int)
-  // XXX: public final Observable flatMap(Function,boolean,int,int)
-  // XXX: public final Observable flatMap(Function,Function,Callable)
-  // XXX: public final Observable flatMap(Function,Function,Callable,int)
-  // XXX: public final Observable flatMap(Function,int)
-  // XXX: public final Completable flatMapCompletable(Function)
-  // XXX: public final Completable flatMapCompletable(Function,boolean)
-
-  static final class ObservableFromIterable<T> {
-    @BeforeTemplate
-    Observable<T> before(Iterable<? extends T> iterable) {
-      return Observable.fromIterable(iterable);
-    }
-
-    @AfterTemplate
-    Observable<T> after(Iterable<? extends T> iterable) {
-      return RxJava2Adapter.fluxToObservable(Flux.fromIterable(iterable));
-    }
-  }
-
-  // XXX: public final Observable flatMapIterable(Function,BiFunction)
-
-  static final class ObservableFlatMapMaybe<T, R, O extends R, M extends MaybeSource<O>> {
-    Observable<O> before(
-        Observable<T> observable, Function<? super T, ? extends MaybeSource<? extends O>> mapper) {
-      return observable.flatMapMaybe(mapper);
-    }
-
-    Observable<O> after(Observable<T> observable, Function<T, M> mapper) {
-      return RxJava2Adapter.fluxToObservable(
-          RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-              .flatMap(
-                  t ->
-                      RxJava2Adapter.maybeToMono(
-                          Maybe.wrap(
-                              RxJavaReactorMigrationUtil.<T, M>toJdkFunction(mapper).apply(t)))));
-    }
-  } // XXX: public final Observable flatMapMaybe(Function,boolean)
-  // XXX: public final Observable flatMapSingle(Function)
-  // XXX: public final Observable flatMapSingle(Function,boolean)
-  // XXX: public final Disposable forEach(Consumer)
-  // XXX: public final Disposable forEachWhile(Predicate)
-  // XXX: public final Disposable forEachWhile(Predicate,Consumer)
-  // XXX: public final Disposable forEachWhile(Predicate,Consumer,Action)
-  // XXX: public final Observable groupBy(Function)
-  // XXX: public final Observable groupBy(Function,boolean)
-  // XXX: public final Observable groupBy(Function,Function)
-  // XXX: public final Observable groupBy(Function,Function,boolean)
-  // XXX: public final Observable groupBy(Function,Function,boolean,int)
-  // XXX: public final Observable groupJoin(ObservableSource,Function,Function,BiFunction)
-  // XXX: public final Observable hide()
-
-  static final class ObservableIgnoreElements<T> {
-    @BeforeTemplate
-    Completable before(Observable<T> observable) {
-      return observable.ignoreElements();
-    }
-
-    @AfterTemplate
-    Completable after(Observable<T> observable) {
-      return RxJava2Adapter.monoToCompletable(
-          RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-              .ignoreElements()
-              .then());
-    }
-  }
-
-  // XXX: public final Single isEmpty()
-  // XXX: public final Observable join(ObservableSource,Function,Function,BiFunction)
-  // XXX: public final Single last(Object)
-  // XXX: public final Maybe lastElement()
-  // XXX: public final Single lastOrError()
-  // XXX: public final Observable lift(ObservableOperator)
-  // XXX: public final Observable map(Function)
-  // XXX: public final Observable materialize()
-  // XXX: public final Observable mergeWith(CompletableSource)
-  // XXX: public final Observable mergeWith(MaybeSource)
-  // XXX: public final Observable mergeWith(ObservableSource)
-  // XXX: public final Observable mergeWith(SingleSource)
-  // XXX: public final Observable observeOn(Scheduler)
-  // XXX: public final Observable observeOn(Scheduler,boolean)
-  // XXX: public final Observable observeOn(Scheduler,boolean,int)
-  // XXX: public final Observable ofType(Class)
-  // XXX: public final Observable onErrorResumeNext(Function)
-  // XXX: public final Observable onErrorResumeNext(ObservableSource)
-  // XXX: public final Observable onErrorReturn(Function)
-  // XXX: public final Observable onErrorReturnItem(Object)
-  // XXX: public final Observable onExceptionResumeNext(ObservableSource)
-  // XXX: public final Observable onTerminateDetach()
-  // XXX: public final ConnectableObservable publish()
-  // XXX: public final Observable publish(Function)
-  // XXX: public final Maybe reduce(BiFunction)
-  // XXX: public final Single reduce(Object,BiFunction)
-  // XXX: public final Single reduceWith(Callable,BiFunction)
-  // XXX: public final Observable repeat()
-  // XXX: public final Observable repeat(long)
-  // XXX: public final Observable repeatUntil(BooleanSupplier)
-  // XXX: public final Observable repeatWhen(Function)
-  // XXX: public final ConnectableObservable replay()
-  // XXX: public final Observable replay(Function)
-  // XXX: public final Observable replay(Function,int)
-  // XXX: public final Observable replay(Function,int,long,TimeUnit)
-  // XXX: public final Observable replay(Function,int,long,TimeUnit,Scheduler)
-  // XXX: public final Observable replay(Function,int,Scheduler)
-  // XXX: public final Observable replay(Function,long,TimeUnit)
-  // XXX: public final Observable replay(Function,long,TimeUnit,Scheduler)
-  // XXX: public final Observable replay(Function,Scheduler)
-  // XXX: public final ConnectableObservable replay(int)
-  // XXX: public final ConnectableObservable replay(int,long,TimeUnit)
-  // XXX: public final ConnectableObservable replay(int,long,TimeUnit,Scheduler)
-  // XXX: public final ConnectableObservable replay(int,Scheduler)
-  // XXX: public final ConnectableObservable replay(long,TimeUnit)
-  // XXX: public final ConnectableObservable replay(long,TimeUnit,Scheduler)
-  // XXX: public final ConnectableObservable replay(Scheduler)
-  // XXX: public final Observable retry()
-  // XXX: public final Observable retry(BiPredicate)
-  // XXX: public final Observable retry(long)
-  // XXX: public final Observable retry(long,Predicate)
-  // XXX: public final Observable retry(Predicate)
-  // XXX: public final Observable retryUntil(BooleanSupplier)
-  // XXX: public final Observable retryWhen(Function)
-  // XXX: public final void safeSubscribe(Observer)
-  // XXX: public final Observable sample(long,TimeUnit)
-  // XXX: public final Observable sample(long,TimeUnit,boolean)
-  // XXX: public final Observable sample(long,TimeUnit,Scheduler)
-  // XXX: public final Observable sample(long,TimeUnit,Scheduler,boolean)
-  // XXX: public final Observable sample(ObservableSource)
-  // XXX: public final Observable sample(ObservableSource,boolean)
-  // XXX: public final Observable scan(BiFunction)
-  // XXX: public final Observable scan(Object,BiFunction)
-  // XXX: public final Observable scanWith(Callable,BiFunction)
-  // XXX: public final Observable serialize()
-  // XXX: public final Observable share()
-  // XXX: public final Single single(Object)
-  // XXX: public final Maybe singleElement()
-  // XXX: public final Single singleOrError()
-  // XXX: public final Observable skip(long)
-  // XXX: public final Observable skip(long,TimeUnit)
-  // XXX: public final Observable skip(long,TimeUnit,Scheduler)
-  // XXX: public final Observable skipLast(int)
-  // XXX: public final Observable skipLast(long,TimeUnit)
-  // XXX: public final Observable skipLast(long,TimeUnit,boolean)
-  // XXX: public final Observable skipLast(long,TimeUnit,Scheduler)
-  // XXX: public final Observable skipLast(long,TimeUnit,Scheduler,boolean)
-  // XXX: public final Observable skipLast(long,TimeUnit,Scheduler,boolean,int)
-  // XXX: public final Observable skipUntil(ObservableSource)
-  // XXX: public final Observable skipWhile(Predicate)
-  // XXX: public final Observable sorted()
-  // XXX: public final Observable sorted(Comparator)
-  // XXX: public final Observable startWith(Iterable)
-  // XXX: public final Observable startWith(Object)
-  // XXX: public final Observable startWith(ObservableSource)
-  // XXX: public final Observable startWithArray(Object[])
-  // XXX: public final Disposable subscribe()
-  // XXX: public final Disposable subscribe(Consumer)
-  // XXX: public final Disposable subscribe(Consumer,Consumer)
-  // XXX: public final Disposable subscribe(Consumer,Consumer,Action)
-  // XXX: public final Disposable subscribe(Consumer,Consumer,Action,Consumer)
-  // XXX: public final void subscribe(Observer)
-  // XXX: public final Observable subscribeOn(Scheduler)
-  // XXX: public final Observer subscribeWith(Observer)
-  // XXX: public final Observable switchIfEmpty(ObservableSource)
-  // XXX: public final Observable switchMap(Function)
-  // XXX: public final Observable switchMap(Function,int)
-  // XXX: public final Completable switchMapCompletable(Function)
-  // XXX: public final Completable switchMapCompletableDelayError(Function)
-  // XXX: public final Observable switchMapDelayError(Function)
-  // XXX: public final Observable switchMapDelayError(Function,int)
-  // XXX: public final Observable switchMapMaybe(Function)
-  // XXX: public final Observable switchMapMaybeDelayError(Function)
-  // XXX: public final Observable switchMapSingle(Function)
-  // XXX: public final Observable switchMapSingleDelayError(Function)
-  // XXX: public final Observable take(long)
-  // XXX: public final Observable take(long,TimeUnit)
-  // XXX: public final Observable take(long,TimeUnit,Scheduler)
-  // XXX: public final Observable takeLast(int)
-  // XXX: public final Observable takeLast(long,long,TimeUnit)
-  // XXX: public final Observable takeLast(long,long,TimeUnit,Scheduler)
-  // XXX: public final Observable takeLast(long,long,TimeUnit,Scheduler,boolean,int)
-  // XXX: public final Observable takeLast(long,TimeUnit)
-  // XXX: public final Observable takeLast(long,TimeUnit,boolean)
-  // XXX: public final Observable takeLast(long,TimeUnit,Scheduler)
-  // XXX: public final Observable takeLast(long,TimeUnit,Scheduler,boolean)
-  // XXX: public final Observable takeLast(long,TimeUnit,Scheduler,boolean,int)
-  // XXX: public final Observable takeUntil(ObservableSource)
-  // XXX: public final Observable takeUntil(Predicate)
-  // XXX: public final Observable takeWhile(Predicate)
-  // XXX: public final Observable throttleFirst(long,TimeUnit)
-  // XXX: public final Observable throttleFirst(long,TimeUnit,Scheduler)
-  // XXX: public final Observable throttleLast(long,TimeUnit)
-  // XXX: public final Observable throttleLast(long,TimeUnit,Scheduler)
-  // XXX: public final Observable throttleLatest(long,TimeUnit)
-  // XXX: public final Observable throttleLatest(long,TimeUnit,boolean)
-  // XXX: public final Observable throttleLatest(long,TimeUnit,Scheduler)
-  // XXX: public final Observable throttleLatest(long,TimeUnit,Scheduler,boolean)
-  // XXX: public final Observable throttleWithTimeout(long,TimeUnit)
-  // XXX: public final Observable throttleWithTimeout(long,TimeUnit,Scheduler)
-  // XXX: public final Observable timeInterval()
-  // XXX: public final Observable timeInterval(Scheduler)
-  // XXX: public final Observable timeInterval(TimeUnit)
-  // XXX: public final Observable timeInterval(TimeUnit,Scheduler)
-  // XXX: public final Observable timeout(Function)
-  // XXX: public final Observable timeout(Function,ObservableSource)
-  // XXX: public final Observable timeout(long,TimeUnit)
-  // XXX: public final Observable timeout(long,TimeUnit,ObservableSource)
-  // XXX: public final Observable timeout(long,TimeUnit,Scheduler)
-  // XXX: public final Observable timeout(long,TimeUnit,Scheduler,ObservableSource)
-  // XXX: public final Observable timeout(ObservableSource,Function)
-  // XXX: public final Observable timeout(ObservableSource,Function,ObservableSource)
-  // XXX: public final Observable timestamp()
-  // XXX: public final Observable timestamp(Scheduler)
-  // XXX: public final Observable timestamp(TimeUnit)
-  // XXX: public final Observable timestamp(TimeUnit,Scheduler)
-  // XXX: public final Object to(Function)
-
-  static final class CompletableToFlowable<T> {
-    @BeforeTemplate
-    Flowable<T> before(Observable<T> observable, BackpressureStrategy strategy) {
-      return observable.toFlowable(strategy);
-    }
-
-    @AfterTemplate
-    Flowable<T> after(Observable<T> observable, BackpressureStrategy strategy) {
-      return RxJava2Adapter.fluxToFlowable(RxJava2Adapter.observableToFlux(observable, strategy));
-    }
-  }
-
-  // XXX: public final Future toFuture()
-  // XXX: public final Single toList()
-  // XXX: public final Single toList(Callable)
-  // XXX: public final Single toList(int)
-  // XXX: public final Single toMap(Function)
-  // XXX: public final Single toMap(Function,Function)
-  // XXX: public final Single toMap(Function,Function,Callable)
-  // XXX: public final Single toMultimap(Function)
-  // XXX: public final Single toMultimap(Function,Function)
-  // XXX: public final Single toMultimap(Function,Function,Callable)
-  // XXX: public final Single toMultimap(Function,Function,Callable,Function)
-  // XXX: public final Single toSortedList()
-  // XXX: public final Single toSortedList(Comparator)
-  // XXX: public final Single toSortedList(Comparator,int)
-  // XXX: public final Single toSortedList(int)
-  // XXX: public final Observable unsubscribeOn(Scheduler)
-  // XXX: public final Observable window(Callable)
-  // XXX: public final Observable window(Callable,int)
-  // XXX: public final Observable window(long)
-  // XXX: public final Observable window(long,long)
-  // XXX: public final Observable window(long,long,int)
-  // XXX: public final Observable window(long,long,TimeUnit)
-  // XXX: public final Observable window(long,long,TimeUnit,Scheduler)
-  // XXX: public final Observable window(long,long,TimeUnit,Scheduler,int)
-  // XXX: public final Observable window(long,TimeUnit)
-  // XXX: public final Observable window(long,TimeUnit,long)
-  // XXX: public final Observable window(long,TimeUnit,long,boolean)
-  // XXX: public final Observable window(long,TimeUnit,Scheduler)
-  // XXX: public final Observable window(long,TimeUnit,Scheduler,long)
-  // XXX: public final Observable window(long,TimeUnit,Scheduler,long,boolean)
-  // XXX: public final Observable window(long,TimeUnit,Scheduler,long,boolean,int)
-  // XXX: public final Observable window(ObservableSource)
-  // XXX: public final Observable window(ObservableSource,Function)
-  // XXX: public final Observable window(ObservableSource,Function,int)
-  // XXX: public final Observable window(ObservableSource,int)
-  // XXX: public final Observable withLatestFrom(Iterable,Function)
-  // XXX: public final Observable withLatestFrom(ObservableSource,BiFunction)
-  // XXX: public final Observable withLatestFrom(ObservableSource[],Function)
-  // XXX: public final Observable withLatestFrom(ObservableSource,ObservableSource,Function3)
-  // XXX: public final Observable
-  // withLatestFrom(ObservableSource,ObservableSource,ObservableSource,Function4)
-  // XXX: public final Observable
-  // withLatestFrom(ObservableSource,ObservableSource,ObservableSource,ObservableSource,Function5)
-  // XXX: public final Observable zipWith(Iterable,BiFunction)
-  // XXX: public final Observable zipWith(ObservableSource,BiFunction)
-  // XXX: public final Observable zipWith(ObservableSource,BiFunction,boolean)
-  // XXX: public final Observable zipWith(ObservableSource,BiFunction,boolean,int)
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertResultItem<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, T item) throws InterruptedException {
-      Refaster.anyOf(
-          observable.test().await().assertResult(item),
-          observable.test().await().assertValue(item));
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable, T item) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .expectNext(item)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  @SuppressWarnings("unchecked")
-  static final class ObservableTestAssertResult<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable) throws InterruptedException {
-      Refaster.anyOf(observable.test().await().assertResult(), observable.test().await());
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .verifyComplete();
-    }
-  }
-
-  @SuppressWarnings("unchecked")
-  static final class ObservableTestAssertResultTwoItems<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, T t1, T t2) throws InterruptedException {
-      observable.test().await().assertResult(t1, t2);
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable, T t1, T t2) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .expectNext(t1, t2)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertValue<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, Predicate<T> predicate) throws InterruptedException {
-      Refaster.anyOf(
-          observable.test().await().assertValue(predicate),
-          observable.test().await().assertValue(predicate).assertNoErrors().assertComplete(),
-          observable.test().await().assertComplete().assertValue(predicate),
-          observable.test().await().assertValue(predicate).assertComplete());
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable, Predicate<T> predicate) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .expectNextMatches(RxJavaReactorMigrationUtil.toJdkPredicate(predicate))
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertResultValues<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, @Repeated T item) throws InterruptedException {
-      Refaster.anyOf(
-          observable.test().await().assertResult(Refaster.asVarargs(item)),
-          observable.test().await().assertValues(Refaster.asVarargs(item)));
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable, @Repeated T item) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .expectNext(item)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertComplete<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable) throws InterruptedException {
-      observable.test().await().assertComplete();
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertErrorClass<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, Class<? extends Throwable> errorClass)
-        throws InterruptedException {
-      observable.test().await().assertError(errorClass);
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable, Class<? extends Throwable> errorClass) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .verifyError(errorClass);
-    }
-  }
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertNoErrors<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable) throws InterruptedException {
-      observable.test().await().assertNoErrors();
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertValueCount<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, int count) throws InterruptedException {
-      observable.test().await().assertValueCount(count);
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable, int count) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .expectNextCount(count)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Add test
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  @SuppressWarnings("unchecked")
-  static final class ObservableTestAssertFailure<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, Class<? extends Throwable> error)
-        throws InterruptedException {
-      observable.test().await().assertFailure(error);
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable, Class<? extends Throwable> error) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .verifyError(error);
-    }
-  }
-
-  // XXX: Add test
-  // XXX: Default BackpressureStrategy.BUFFER is set
-  static final class ObservableTestAssertNoValues<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable) throws InterruptedException {
-      Refaster.anyOf(
-          observable.test().await().assertNoValues(),
-          observable.test().await().assertNoValues().assertComplete());
-    }
-
-    @AfterTemplate
-    void after(Observable<T> observable) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Add test
-  // XXX: This introduces AssertJ dependency
-  @SuppressWarnings("unchecked")
-  static final class ObservableTestAssertFailureAndMessage<T> {
-    @BeforeTemplate
-    void before(Observable<T> observable, Class<? extends Throwable> error, String message)
-        throws InterruptedException {
-      observable.test().await().assertFailureAndMessage(error, message);
-    }
-
-    @AfterTemplate
-    @UseImportPolicy(ImportPolicy.IMPORT_CLASS_DIRECTLY)
-    void after(Observable<T> observable, Class<? extends Throwable> error, String message) {
-      RxJava2Adapter.observableToFlux(observable, BackpressureStrategy.BUFFER)
-          .as(StepVerifier::create)
-          .expectErrorSatisfies(
-              t -> assertThat(t).isInstanceOf(error).hasMessageContaining(message))
-          .verify();
-    }
-  }
-
-  // XXX: public final TestObserver test(boolean)
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJavaSingleToReactorTemplates.java

@@ -1,764 +0,0 @@
-package tech.picnic.errorprone.refastertemplates;
-
-import static org.assertj.core.api.Assertions.assertThat;
-
-import com.google.common.collect.ImmutableSet;
-import com.google.errorprone.refaster.ImportPolicy;
-import com.google.errorprone.refaster.Refaster;
-import com.google.errorprone.refaster.annotation.AfterTemplate;
-import com.google.errorprone.refaster.annotation.BeforeTemplate;
-import com.google.errorprone.refaster.annotation.MayOptionallyUse;
-import com.google.errorprone.refaster.annotation.Placeholder;
-import com.google.errorprone.refaster.annotation.UseImportPolicy;
-import io.reactivex.Completable;
-import io.reactivex.CompletableSource;
-import io.reactivex.Flowable;
-import io.reactivex.Maybe;
-import io.reactivex.MaybeSource;
-import io.reactivex.Single;
-import io.reactivex.SingleSource;
-import io.reactivex.disposables.Disposable;
-import io.reactivex.functions.BiFunction;
-import io.reactivex.functions.Consumer;
-import io.reactivex.functions.Function;
-import io.reactivex.functions.Predicate;
-import io.reactivex.schedulers.Schedulers;
-import java.util.concurrent.Callable;
-import org.reactivestreams.Publisher;
-import reactor.adapter.rxjava.RxJava2Adapter;
-import reactor.core.publisher.Mono;
-import reactor.test.StepVerifier;
-import tech.picnic.errorprone.migration.util.RxJavaReactorMigrationUtil;
-
-/** The Refaster templates for the migration of the RxJava Single type to Reactor */
-final class RxJavaSingleToReactorTemplates {
-
-  private RxJavaSingleToReactorTemplates() {}
-
-  // XXX: public static Single amb(Iterable)
-  // XXX: public static Single ambArray(SingleSource[])
-  // XXX: public static Flowable concat(Iterable)
-  // XXX: public static Observable concat(ObservableSource)
-  // XXX: public static Flowable concat(Publisher)
-  // XXX: public static Flowable concat(Publisher,int)
-  // XXX: public static Flowable concat(SingleSource,SingleSource)
-  // XXX: public static Flowable concat(SingleSource,SingleSource,SingleSource)
-  // XXX: public static Flowable concat(SingleSource,SingleSource,SingleSource,SingleSource)
-  // XXX: public static Flowable concatArray(SingleSource[])
-  // XXX: public static Flowable concatArrayEager(SingleSource[])
-  // XXX: public static Flowable concatEager(Iterable)
-  // XXX: public static Flowable concatEager(Publisher)
-  // XXX: public static Single create(SingleOnSubscribe)
-
-  abstract static class SingleDeferFirst<T> {
-    @Placeholder
-    abstract Single<? extends T> singleProducer();
-
-    @BeforeTemplate
-    Single<T> before() {
-      return Single.defer(() -> singleProducer());
-    }
-
-    @AfterTemplate
-    Single<? extends T> after() {
-      return RxJava2Adapter.monoToSingle(
-          Mono.defer(() -> RxJava2Adapter.singleToMono(singleProducer())));
-    }
-  }
-
-  // XXX: public static Single equals(SingleSource,SingleSource)
-
-  static final class SingleErrorCallable<T> {
-    @BeforeTemplate
-    Single<T> before(Callable<? extends Throwable> throwable) {
-      return Single.error(throwable);
-    }
-
-    @UseImportPolicy(ImportPolicy.IMPORT_CLASS_DIRECTLY)
-    @AfterTemplate
-    Single<T> after(Callable<? extends Throwable> throwable) {
-      return RxJava2Adapter.monoToSingle(
-          Mono.error(RxJavaReactorMigrationUtil.callableAsSupplier(throwable)));
-    }
-  }
-
-  static final class SingleErrorThrowable<T> {
-    @BeforeTemplate
-    Single<T> before(Throwable throwable) {
-      return Single.error(throwable);
-    }
-
-    @AfterTemplate
-    Single<T> after(Throwable throwable) {
-      return RxJava2Adapter.monoToSingle(Mono.error(throwable));
-    }
-  }
-
-  static final class SingleFromCallable<T> {
-    @BeforeTemplate
-    Single<T> before(Callable<? extends T> callable) {
-      return Single.fromCallable(callable);
-    }
-
-    @UseImportPolicy(ImportPolicy.IMPORT_CLASS_DIRECTLY)
-    @AfterTemplate
-    Single<T> after(Callable<? extends T> callable) {
-      return RxJava2Adapter.monoToSingle(
-          Mono.fromSupplier(RxJavaReactorMigrationUtil.callableAsSupplier(callable)));
-    }
-  }
-
-  // XXX: public static Single fromFuture(Future)
-  // XXX: public static Single fromFuture(Future,long,TimeUnit)
-  // XXX: public static Single fromFuture(Future,long,TimeUnit,Scheduler)
-  // XXX: public static Single fromFuture(Future,Scheduler)
-  // XXX: public static Single fromObservable(ObservableSource)
-
-  static final class SingleFromPublisher<T> {
-    @BeforeTemplate
-    Single<T> before(Publisher<? extends T> source) {
-      return Single.fromPublisher(source);
-    }
-
-    @AfterTemplate
-    Single<T> after(Publisher<? extends T> source) {
-      return RxJava2Adapter.monoToSingle(Mono.from(source));
-    }
-  }
-
-  static final class SingleJust<T> {
-    @BeforeTemplate
-    Single<T> before(T item) {
-      return Single.just(item);
-    }
-
-    @AfterTemplate
-    Single<T> after(T item) {
-      return RxJava2Adapter.monoToSingle(Mono.just(item));
-    }
-  }
-
-  // XXX: public static Flowable merge(Iterable)
-  // XXX: public static Flowable merge(Publisher)
-  // XXX: public static Single merge(SingleSource)
-  // XXX: public static Flowable merge(SingleSource,SingleSource)
-  // XXX: public static Flowable merge(SingleSource,SingleSource,SingleSource)
-  // XXX: public static Flowable merge(SingleSource,SingleSource,SingleSource,SingleSource)
-  // XXX: public static Flowable mergeDelayError(Iterable)
-  // XXX: public static Flowable mergeDelayError(Publisher)
-  // XXX: public static Flowable mergeDelayError(SingleSource,SingleSource)
-  // XXX: public static Flowable mergeDelayError(SingleSource,SingleSource,SingleSource)
-  // XXX: public static Flowable
-  // mergeDelayError(SingleSource,SingleSource,SingleSource,SingleSource)
-  // XXX: public static Single never()
-  static final class SingleNever {
-    @BeforeTemplate
-    <T> Single<T> before() {
-      return Single.never();
-    }
-
-    @AfterTemplate
-    <T> Single<T> after() {
-      return RxJava2Adapter.monoToSingle(Mono.never());
-    }
-  }
-  // XXX: public static Single timer(long,TimeUnit)
-  // XXX: public static Single timer(long,TimeUnit,Scheduler)
-  // XXX: public static Single unsafeCreate(SingleSource)
-  // XXX: public static Single using(Callable,Function,Consumer)
-  // XXX: public static Single using(Callable,Function,Consumer,boolean)
-
-  static final class SingleWrap<T> {
-    @BeforeTemplate
-    Single<T> before(Single<T> single) {
-      return Single.wrap(single);
-    }
-
-    @AfterTemplate
-    Single<T> after(Single<T> single) {
-      return single;
-    }
-  }
-
-  // XXX: public static Single zip(Iterable,Function)
-  // XXX: public static Single zip(SingleSource,SingleSource,BiFunction)
-  // XXX: public static Single zip(SingleSource,SingleSource,SingleSource,Function3)
-  // XXX: public static Single zip(SingleSource,SingleSource,SingleSource,SingleSource,Function4)
-  // XXX: public static Single
-  // zip(SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,Function5)
-  // XXX: public static Single
-  // zip(SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,Function6)
-  // XXX: public static Single
-  // zip(SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,Function7)
-  // XXX: public static Single
-  // zip(SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,Function8)
-  // XXX: public static Single
-  // zip(SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,SingleSource,Function9)
-  // XXX: public static Single zipArray(Function,SingleSource[])
-  // XXX: public final Single ambWith(SingleSource)
-  // XXX: public final Object as(SingleConverter)
-
-  static final class SingleBlockingGet<T> {
-    @BeforeTemplate
-    Object before(Single<T> single) {
-      return single.blockingGet();
-    }
-
-    @AfterTemplate
-    Object after(Single<T> single) {
-      return RxJava2Adapter.singleToMono(single).block();
-    }
-  }
-
-  // XXX: public final Single cache()
-  // XXX: public final Single cast(Class)
-  // XXX: public final Single compose(SingleTransformer)
-
-  static final class SingleConcatWith<T> {
-    @BeforeTemplate
-    Flowable<T> before(Single<T> single, SingleSource<? extends T> source) {
-      return single.concatWith(source);
-    }
-
-    @AfterTemplate
-    Flowable<T> after(Single<T> single, SingleSource<? extends T> source) {
-      return RxJava2Adapter.fluxToFlowable(
-          RxJava2Adapter.singleToMono(single)
-              .concatWith(RxJava2Adapter.singleToMono(Single.wrap(source))));
-    }
-  }
-
-  // XXX: public final Single contains(Object)
-  // XXX: public final Single contains(Object,BiPredicate)
-  // XXX: public final Single delay(long,TimeUnit)
-  // XXX: public final Single delay(long,TimeUnit,boolean)
-  // XXX: public final Single delay(long,TimeUnit,Scheduler)
-  // XXX: public final Single delay(long,TimeUnit,Scheduler,boolean)
-  // XXX: public final Single delaySubscription(CompletableSource)
-  // XXX: public final Single delaySubscription(long,TimeUnit)
-  // XXX: public final Single delaySubscription(long,TimeUnit,Scheduler)
-  // XXX: public final Single delaySubscription(ObservableSource)
-  // XXX: public final Single delaySubscription(Publisher)
-  // XXX: public final Single delaySubscription(SingleSource)
-  // XXX: public final Maybe dematerialize(Function)
-  // XXX: public final Single doAfterSuccess(Consumer)
-  // XXX: public final Single doAfterTerminate(Action)
-  // XXX: public final Single doFinally(Action)
-  // XXX: public final Single doOnDispose(Action)
-
-  static final class SingleDoOnError<T> {
-    @BeforeTemplate
-    Single<T> before(Single<T> single, Consumer<? super Throwable> consumer) {
-      return single.doOnError(consumer);
-    }
-
-    @AfterTemplate
-    Single<T> after(Single<T> single, Consumer<? super Throwable> consumer) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .doOnError(RxJavaReactorMigrationUtil.toJdkConsumer(consumer)));
-    }
-  }
-
-  // XXX: public final Single doOnEvent(BiConsumer)
-  // XXX: public final Single doOnSubscribe(Consumer)
-
-  static final class SingleDoOnSuccess<T> {
-    @BeforeTemplate
-    Single<T> before(Single<T> single, Consumer<T> consumer) {
-      return single.doOnSuccess(consumer);
-    }
-
-    @AfterTemplate
-    Single<T> after(Single<T> single, Consumer<T> consumer) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .doOnSuccess(RxJavaReactorMigrationUtil.toJdkConsumer(consumer)));
-    }
-  }
-
-  // XXX: public final Single doOnTerminate(Action)
-
-  static final class SingleFilter<S, T extends S> {
-    @BeforeTemplate
-    Maybe<T> before(Single<T> single, Predicate<S> predicate) {
-      return single.filter(predicate);
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Single<T> single, Predicate<S> predicate) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.singleToMono(single)
-              .filter(RxJavaReactorMigrationUtil.toJdkPredicate(predicate)));
-    }
-  }
-
-  // XXX: Add test
-  static final class SingleFlatMapFunction<I, T extends I, O, M extends SingleSource<O>> {
-    @BeforeTemplate
-    Single<O> before(
-        Single<T> single, Function<? super I, ? extends SingleSource<? extends O>> function) {
-      return single.flatMap(function);
-    }
-
-    @AfterTemplate
-    @UseImportPolicy(ImportPolicy.IMPORT_CLASS_DIRECTLY)
-    Single<O> after(Single<T> single, Function<I, M> function) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .flatMap(
-                  v ->
-                      RxJava2Adapter.singleToMono(
-                          Single.wrap(
-                              RxJavaReactorMigrationUtil.<I, M>toJdkFunction(function).apply(v)))));
-    }
-  }
-
-  abstract static class SingleFlatMapLambda<S, T> {
-    @Placeholder
-    abstract Single<T> toSingleFunction(@MayOptionallyUse S element);
-
-    @BeforeTemplate
-    Single<T> before(Single<S> single) {
-      return Refaster.anyOf(
-          single.flatMap(v -> toSingleFunction(v)), single.flatMap((S v) -> toSingleFunction(v)));
-    }
-
-    @AfterTemplate
-    Single<T> after(Single<S> single) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .flatMap(v -> RxJava2Adapter.singleToMono(toSingleFunction(v))));
-    }
-  }
-
-  static final class SingleFlatMapCompletable<T, R extends CompletableSource> {
-    @BeforeTemplate
-    Completable before(
-        Single<T> single, Function<? super T, ? extends CompletableSource> function) {
-      return single.flatMapCompletable(function);
-    }
-
-    @AfterTemplate
-    Completable after(Single<T> single, Function<T, R> function) {
-      return RxJava2Adapter.monoToCompletable(
-          RxJava2Adapter.singleToMono(single)
-              .flatMap(
-                  z ->
-                      RxJava2Adapter.completableToMono(
-                          Completable.wrap(
-                              RxJavaReactorMigrationUtil.<T, R>toJdkFunction(function).apply(z))))
-              .then());
-    }
-  }
-
-  // XXX: Add test
-  static final class SingleFlatMapMaybe<T, R, M extends MaybeSource<R>> {
-    @BeforeTemplate
-    Maybe<R> before(
-        Single<T> single, Function<? super T, ? extends MaybeSource<? extends R>> mapper) {
-      return single.flatMapMaybe(mapper);
-    }
-
-    @AfterTemplate
-    Maybe<R> after(Single<T> single, Function<T, M> mapper) {
-      return RxJava2Adapter.monoToMaybe(
-          RxJava2Adapter.singleToMono(single)
-              .flatMap(
-                  e ->
-                      RxJava2Adapter.maybeToMono(
-                          Maybe.wrap(
-                              RxJavaReactorMigrationUtil.<T, M>toJdkFunction(mapper).apply(e)))));
-    }
-  }
-
-  // XXX: public final Observable flatMapObservable(Function)
-
-  static final class SingleFlatMapPublisher<T, R> {
-    @BeforeTemplate
-    Flowable<R> before(
-        Single<T> single, Function<? super T, ? extends Publisher<? extends R>> mapper) {
-      return single.flatMapPublisher(mapper);
-    }
-
-    @AfterTemplate
-    Flowable<R> after(
-        Single<T> single, Function<? super T, ? extends Publisher<? extends R>> mapper) {
-      return RxJava2Adapter.fluxToFlowable(
-          RxJava2Adapter.singleToMono(single)
-              .flatMapMany(RxJavaReactorMigrationUtil.toJdkFunction(mapper)));
-    }
-  }
-
-  // XXX: public final Flowable flattenAsFlowable(Function)
-  // XXX: public final Observable flattenAsObservable(Function)
-  // XXX: public final Single hide()
-
-  static final class CompletableIgnoreElement<T> {
-    @BeforeTemplate
-    Completable before(Single<T> single) {
-      return single.ignoreElement();
-    }
-
-    @AfterTemplate
-    Completable after(Single<T> single) {
-      return RxJava2Adapter.monoToCompletable(RxJava2Adapter.singleToMono(single).then());
-    }
-  }
-
-  // XXX: public final Single lift(SingleOperator)
-
-  static final class SingleMap<I, T extends I, O> {
-    @BeforeTemplate
-    Single<O> before(Single<T> single, Function<? super I, ? extends O> function) {
-      return single.map(function);
-    }
-
-    @AfterTemplate
-    Single<O> after(Single<T> single, Function<I, O> function) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .map(RxJavaReactorMigrationUtil.toJdkFunction(function)));
-    }
-  }
-
-  // XXX: public final Single materialize()
-  // XXX: public final Flowable mergeWith(SingleSource)
-  // XXX: public final Single observeOn(Scheduler)
-
-  static final class SingleOnErrorResumeNext<
-      S, T extends S, R, P extends Throwable, Q extends Single<T>> {
-    @BeforeTemplate
-    Single<T> before(
-        Single<T> single,
-        Function<? super Throwable, ? extends SingleSource<? extends T>> function) {
-      return single.onErrorResumeNext(function);
-    }
-
-    @AfterTemplate
-    Single<T> after(Single<T> single, Function<Throwable, Q> function) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .onErrorResume(
-                  err ->
-                      RxJava2Adapter.singleToMono(
-                          RxJavaReactorMigrationUtil.<Throwable, Q>toJdkFunction(function)
-                              .apply(err))));
-    }
-  }
-
-  // XXX: public final Single onErrorResumeNext(Single)
-  // XXX: public final Single onErrorReturn(Function)
-  // XXX: public final Single onErrorReturnItem(Object)
-  // XXX: public final Single onTerminateDetach()
-  // XXX: public final Flowable repeat()
-  // XXX: public final Flowable repeat(long)
-  // XXX: public final Flowable repeatUntil(BooleanSupplier)
-  // XXX: public final Flowable repeatWhen(Function)
-  // XXX: public final Single retry()
-  // XXX: public final Single retry(BiPredicate)
-  // XXX: public final Single retry(long)
-  // XXX: public final Single retry(long,Predicate)
-  // XXX: public final Single retry(Predicate)
-  // XXX: public final Single retryWhen(Function)
-
-  // XXX: Add test
-  static final class SingleSubscribe<T> {
-    @BeforeTemplate
-    Disposable before(Single<T> single) {
-      return single.subscribe();
-    }
-
-    @AfterTemplate
-    reactor.core.Disposable after(Single<T> single) {
-      return RxJava2Adapter.singleToMono(single).subscribe();
-    }
-  }
-
-  // XXX: public final Disposable subscribe(BiConsumer)
-
-  // XXX: Add test
-  static final class SingleSubscribeConsumer<T> {
-    @BeforeTemplate
-    Disposable before(Single<T> single, Consumer<? super T> consumer) {
-      return single.subscribe(consumer);
-    }
-
-    @AfterTemplate
-    reactor.core.Disposable after(Single<T> single, Consumer<? super T> consumer) {
-      return RxJava2Adapter.singleToMono(single)
-          .subscribe(RxJavaReactorMigrationUtil.toJdkConsumer(consumer));
-    }
-  }
-
-  // XXX: Add test
-  static final class SingleSubscribeTwoConsumers<T> {
-    @BeforeTemplate
-    Disposable before(
-        Single<T> single, Consumer<? super T> consumer1, Consumer<? super Throwable> consumer2) {
-      return single.subscribe(consumer1, consumer2);
-    }
-
-    @AfterTemplate
-    reactor.core.Disposable after(
-        Single<T> single, Consumer<? super T> consumer1, Consumer<? super Throwable> consumer2) {
-      return RxJava2Adapter.singleToMono(single)
-          .subscribe(
-              RxJavaReactorMigrationUtil.toJdkConsumer(consumer1),
-              RxJavaReactorMigrationUtil.toJdkConsumer(consumer2));
-    }
-  }
-
-  // XXX: public final void subscribe(SingleObserver)
-
-  // XXX: We are currently not accounting for the Schedulers.computation()
-  static final class SingleSubscribeOn<T> {
-    @BeforeTemplate
-    Single<T> before(Single<T> single) {
-      return single.subscribeOn(Schedulers.io());
-    }
-
-    @AfterTemplate
-    Single<T> after(Single<T> single) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .subscribeOn(reactor.core.scheduler.Schedulers.boundedElastic()));
-    }
-  }
-
-  // XXX: public final SingleObserver subscribeWith(SingleObserver)
-  // XXX: public final Single takeUntil(CompletableSource)
-  // XXX: public final Single takeUntil(Publisher)
-  // XXX: public final Single takeUntil(SingleSource)
-  // XXX: public final Single timeout(long,TimeUnit)
-  // XXX: public final Single timeout(long,TimeUnit,Scheduler)
-  // XXX: public final Single timeout(long,TimeUnit,Scheduler,SingleSource)
-  // XXX: public final Single timeout(long,TimeUnit,SingleSource)
-  // XXX: public final Object to(Function)
-  // XXX: public final Completable toCompletable()
-
-  static final class SingleToFlowable<T> {
-    @BeforeTemplate
-    Flowable<T> before(Single<T> single) {
-      return single.toFlowable();
-    }
-
-    @AfterTemplate
-    Flowable<T> after(Single<T> single) {
-      return RxJava2Adapter.fluxToFlowable(RxJava2Adapter.singleToMono(single).flux());
-    }
-  }
-
-  // XXX: public final Future toFuture()
-
-  static final class SingleToMaybe<T> {
-    @BeforeTemplate
-    Maybe<T> before(Single<T> single) {
-      return single.toMaybe();
-    }
-
-    @AfterTemplate
-    Maybe<T> after(Single<T> single) {
-      return RxJava2Adapter.monoToMaybe(RxJava2Adapter.singleToMono(single));
-    }
-  }
-
-  // XXX: public final Observable toObservable()
-  // XXX: public final Single unsubscribeOn(Scheduler)
-
-  static final class SingleZipWith<T, R, U> {
-    @BeforeTemplate
-    Single<R> before(
-        Single<T> single,
-        SingleSource<U> source,
-        BiFunction<? super T, ? super U, ? extends R> biFunction) {
-      return single.zipWith(source, biFunction);
-    }
-
-    @AfterTemplate
-    Single<R> after(
-        Single<T> single,
-        SingleSource<U> source,
-        BiFunction<? super T, ? super U, ? extends R> biFunction) {
-      return RxJava2Adapter.monoToSingle(
-          RxJava2Adapter.singleToMono(single)
-              .zipWith(
-                  RxJava2Adapter.singleToMono(Single.wrap(source)),
-                  RxJavaReactorMigrationUtil.toJdkBiFunction(biFunction)));
-    }
-  }
-
-  @SuppressWarnings("unchecked")
-  static final class SingleTestAssertResultItem<T> {
-    @BeforeTemplate
-    void before(Single<T> single, T item) throws InterruptedException {
-      Refaster.anyOf(
-          single.test().assertResult(item),
-          single.test().await().assertResult(item),
-          single.test().await().assertComplete().assertResult(item),
-          single.test().await().assertResult(item).assertComplete(),
-          single.test().await().assertValue(item),
-          single.test().await().assertComplete().assertValue(item),
-          single.test().assertValue(item),
-          single.test().await().assertValue(item).assertComplete());
-    }
-
-    @AfterTemplate
-    void after(Single<T> single, T item) {
-      RxJava2Adapter.singleToMono(single)
-          .as(StepVerifier::create)
-          .expectNext(item)
-          .verifyComplete();
-    }
-  }
-
-  static final class SingleAssertValueSet<T> {
-    @BeforeTemplate
-    void before(Single<T> single, ImmutableSet<? extends T> set) throws InterruptedException {
-      single.test().await().assertNoErrors().assertValueSet(set).assertComplete();
-    }
-
-    @AfterTemplate
-    void after(Single<T> single, ImmutableSet<? extends T> set) {
-      RxJava2Adapter.singleToMono(single)
-          .map(ImmutableSet::of)
-          .as(StepVerifier::create)
-          .expectNext(ImmutableSet.copyOf(set))
-          .verifyComplete();
-    }
-  }
-
-  @SuppressWarnings("unchecked")
-  static final class SingleTestAssertResult<T> {
-    @BeforeTemplate
-    void before(Single<T> single) throws InterruptedException {
-      single.test().await().assertResult();
-    }
-
-    @AfterTemplate
-    void after(Single<T> single) {
-      RxJava2Adapter.singleToMono(single).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class SingleTestAssertValue<T> {
-    @BeforeTemplate
-    void before(Single<T> single, Predicate<T> predicate) throws InterruptedException {
-      Refaster.anyOf(
-          single.test().await().assertValue(predicate),
-          single.test().await().assertValue(predicate).assertComplete(),
-          single.test().await().assertValue(predicate).assertNoErrors().assertComplete(),
-          single.test().await().assertComplete().assertValue(predicate));
-    }
-
-    @AfterTemplate
-    void after(Single<T> single, Predicate<T> predicate) {
-      RxJava2Adapter.singleToMono(single)
-          .as(StepVerifier::create)
-          .expectNextMatches(RxJavaReactorMigrationUtil.toJdkPredicate(predicate))
-          .verifyComplete();
-    }
-  }
-
-  static final class SingleTestAssertComplete<T> {
-    @BeforeTemplate
-    void before(Single<T> single) throws InterruptedException {
-      single.test().await().assertComplete();
-    }
-
-    @AfterTemplate
-    void after(Single<T> single) {
-      RxJava2Adapter.singleToMono(single).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class SingleTestAssertErrorClass<T> {
-    @BeforeTemplate
-    void before(Single<T> single, Class<? extends Throwable> errorClass)
-        throws InterruptedException {
-      single.test().await().assertError(errorClass);
-    }
-
-    @AfterTemplate
-    void after(Single<T> single, Class<? extends Throwable> errorClass) {
-      RxJava2Adapter.singleToMono(single).as(StepVerifier::create).verifyError(errorClass);
-    }
-  }
-
-  static final class SingleTestAssertNoErrors<T> {
-    @BeforeTemplate
-    void before(Single<T> single) throws InterruptedException {
-      single.test().await().assertNoErrors();
-    }
-
-    @AfterTemplate
-    void after(Single<T> single) {
-      RxJava2Adapter.singleToMono(single).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  static final class SingleTestAssertValueCount<T> {
-    @BeforeTemplate
-    void before(Single<T> single, int count) throws InterruptedException {
-      single.test().await().assertValueCount(count);
-    }
-
-    @AfterTemplate
-    void after(Single<T> single, int count) {
-      RxJava2Adapter.singleToMono(single)
-          .as(StepVerifier::create)
-          .expectNextCount(count)
-          .verifyComplete();
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("unchecked")
-  static final class SingleTestAssertFailure<T> {
-    @BeforeTemplate
-    void before(Single<T> single, Class<? extends Throwable> error) throws InterruptedException {
-      single.test().await().assertFailure(error);
-    }
-
-    @AfterTemplate
-    void after(Single<T> single, Class<? extends Throwable> error) {
-      RxJava2Adapter.singleToMono(single).as(StepVerifier::create).verifyError(error);
-    }
-  }
-
-  // XXX: Add test
-  static final class SingleTestAssertNoValues<T> {
-    @BeforeTemplate
-    void before(Single<T> single) throws InterruptedException {
-      Refaster.anyOf(
-          single.test().await().assertNoValues(),
-          single.test().await().assertNoValues().assertComplete());
-    }
-
-    @AfterTemplate
-    void after(Single<T> single) {
-      RxJava2Adapter.singleToMono(single).as(StepVerifier::create).verifyComplete();
-    }
-  }
-
-  // XXX: Add test
-  // XXX: This introduces AssertJ dependency
-  static final class SingleTestAssertFailureAndMessage<T> {
-    @BeforeTemplate
-    void before(Single<T> single, Class<? extends Throwable> error, String message)
-        throws InterruptedException {
-      single.test().await().assertFailureAndMessage(error, message);
-    }
-
-    @AfterTemplate
-    void after(Single<T> single, Class<? extends Throwable> error, String message) {
-      RxJava2Adapter.singleToMono(single)
-          .as(StepVerifier::create)
-          .expectErrorSatisfies(
-              t -> assertThat(t).isInstanceOf(error).hasMessageContaining(message))
-          .verify();
-    }
-  }
-
-  // XXX: public final TestObserver test(boolean)
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJavaToReactorTemplates.java

@@ -1,290 +0,0 @@
-package tech.picnic.errorprone.refastertemplates;
-
-import com.google.errorprone.refaster.Refaster;
-import com.google.errorprone.refaster.annotation.AfterTemplate;
-import com.google.errorprone.refaster.annotation.BeforeTemplate;
-import com.google.errorprone.refaster.annotation.CanTransformToTargetType;
-import io.reactivex.BackpressureStrategy;
-import io.reactivex.Flowable;
-import io.reactivex.functions.Action;
-import io.reactivex.functions.BiFunction;
-import io.reactivex.functions.Consumer;
-import io.reactivex.functions.Function;
-import io.reactivex.functions.Predicate;
-import java.util.concurrent.Callable;
-import java.util.function.Supplier;
-import org.reactivestreams.Publisher;
-import reactor.adapter.rxjava.RxJava2Adapter;
-import reactor.core.publisher.Flux;
-import reactor.core.publisher.Mono;
-import tech.picnic.errorprone.migration.util.RxJavaReactorMigrationUtil;
-
-/** Assorted Refaster templates for the migration of RxJava to Reactor */
-public final class RxJavaToReactorTemplates {
-  private RxJavaToReactorTemplates() {}
-
-  static final class FluxToFlowableToFlux<T> {
-    @BeforeTemplate
-    Flux<T> before(Flux<T> flux, BackpressureStrategy strategy) {
-      return Refaster.anyOf(
-          RxJava2Adapter.fluxToFlowable(flux).as(RxJava2Adapter::flowableToFlux),
-          RxJava2Adapter.flowableToFlux(RxJava2Adapter.fluxToFlowable(flux)),
-          RxJava2Adapter.flowableToFlux(flux.as(RxJava2Adapter::fluxToFlowable)),
-          RxJava2Adapter.observableToFlux(flux.as(RxJava2Adapter::fluxToObservable), strategy),
-          flux.as(RxJava2Adapter::fluxToObservable)
-              .toFlowable(strategy)
-              .as(RxJava2Adapter::flowableToFlux),
-          RxJava2Adapter.observableToFlux(RxJava2Adapter.fluxToObservable(flux), strategy),
-          flux.as(RxJava2Adapter::fluxToFlowable).as(RxJava2Adapter::flowableToFlux));
-    }
-
-    @AfterTemplate
-    Flux<T> after(Flux<T> flux) {
-      return flux;
-    }
-  }
-
-  static final class MonoToFlowableToMono<T> {
-    @BeforeTemplate
-    Mono<Void> before(Mono<Void> mono) {
-      return Refaster.anyOf(
-          RxJava2Adapter.monoToCompletable(mono).as(RxJava2Adapter::completableToMono),
-          mono.as(RxJava2Adapter::monoToCompletable).as(RxJava2Adapter::completableToMono),
-          RxJava2Adapter.completableToMono(RxJava2Adapter.monoToCompletable(mono)),
-          RxJava2Adapter.completableToMono(mono.as(RxJava2Adapter::monoToCompletable)));
-    }
-
-    @BeforeTemplate
-    Mono<T> before2(Mono<T> mono) {
-      return Refaster.anyOf(
-          RxJava2Adapter.monoToMaybe(mono).as(RxJava2Adapter::maybeToMono),
-          RxJava2Adapter.maybeToMono(RxJava2Adapter.monoToMaybe(mono)),
-          RxJava2Adapter.maybeToMono(mono.as(RxJava2Adapter::monoToMaybe)),
-          mono.as(RxJava2Adapter::monoToMaybe).as(RxJava2Adapter::maybeToMono),
-          RxJava2Adapter.monoToSingle(mono).as(RxJava2Adapter::singleToMono),
-          RxJava2Adapter.singleToMono(RxJava2Adapter.monoToSingle(mono)),
-          RxJava2Adapter.singleToMono(mono.as(RxJava2Adapter::monoToSingle)),
-          mono.as(RxJava2Adapter::monoToSingle).as(RxJava2Adapter::singleToMono));
-    }
-
-    @BeforeTemplate
-    Mono<Void> before3(Mono<T> mono) {
-      return Refaster.anyOf(
-          RxJava2Adapter.completableToMono(RxJava2Adapter.monoToCompletable(mono)),
-          RxJava2Adapter.completableToMono(mono.as(RxJava2Adapter::monoToCompletable)),
-          RxJava2Adapter.monoToCompletable(mono).as(RxJava2Adapter::completableToMono));
-    }
-
-    @AfterTemplate
-    Mono<T> after(Mono<T> mono) {
-      return mono;
-    }
-  }
-
-  // XXX: Add test cases
-  static final class MonoToFlowableToFlux<T> {
-    @BeforeTemplate
-    Flux<T> before(Mono<T> mono) {
-      return mono.as(RxJava2Adapter::monoToFlowable).as(RxJava2Adapter::flowableToFlux);
-    }
-
-    @AfterTemplate
-    Flux<T> after(Mono<T> mono) {
-      return mono.flux();
-    }
-  }
-
-  static final class MonoErrorCallableSupplierUtil<T> {
-    @BeforeTemplate
-    Mono<T> before(@CanTransformToTargetType Callable<? extends Throwable> callable) {
-      return Mono.error(RxJavaReactorMigrationUtil.callableAsSupplier(callable));
-    }
-
-    @AfterTemplate
-    Mono<T> after(Supplier<? extends Throwable> callable) {
-      return Mono.error(callable);
-    }
-  }
-
-  @SuppressWarnings({"NoFunctionalReturnType", "FunctionalInterfaceClash"})
-  static final class RemoveUtilCallable<T> {
-    @BeforeTemplate
-    Supplier<T> before(@CanTransformToTargetType Callable<T> callable) {
-      return RxJavaReactorMigrationUtil.callableAsSupplier(callable);
-    }
-
-    @AfterTemplate
-    Supplier<T> before(Supplier<T> callable) {
-      return callable;
-    }
-  }
-
-  @SuppressWarnings("NoFunctionalReturnType")
-  static final class UnnecessaryFunctionConversion<I, O> {
-    @BeforeTemplate
-    java.util.function.Function<I, O> before(@CanTransformToTargetType Function<I, O> function) {
-      return RxJavaReactorMigrationUtil.toJdkFunction(function);
-    }
-
-    @AfterTemplate
-    java.util.function.Function<I, O> after(java.util.function.Function<I, O> function) {
-      return function;
-    }
-  }
-
-  @SuppressWarnings("NoFunctionalReturnType")
-  static final class UnnecessaryBiFunctionConversion<T, U, R> {
-    @BeforeTemplate
-    java.util.function.BiFunction<? super T, ? super U, ? extends R> before(
-        @CanTransformToTargetType BiFunction<? super T, ? super U, ? extends R> zipper) {
-      return RxJavaReactorMigrationUtil.toJdkBiFunction(zipper);
-    }
-
-    @AfterTemplate
-    java.util.function.BiFunction<? super T, ? super U, ? extends R> after(
-        java.util.function.BiFunction<? super T, ? super U, ? extends R> zipper) {
-      return zipper;
-    }
-  }
-
-  @SuppressWarnings("NoFunctionalReturnType")
-  static final class UnnecessaryConsumerConversion<T> {
-    @BeforeTemplate
-    java.util.function.Consumer<? extends T> before(
-        @CanTransformToTargetType Consumer<? extends T> consumer) {
-      return RxJavaReactorMigrationUtil.toJdkConsumer(consumer);
-    }
-
-    @AfterTemplate
-    java.util.function.Consumer<? extends T> after(
-        java.util.function.Consumer<? extends T> consumer) {
-      return consumer;
-    }
-  }
-
-  static final class UnnecessaryRunnableConversion {
-    @BeforeTemplate
-    Runnable before(@CanTransformToTargetType Action action) {
-      return RxJavaReactorMigrationUtil.toRunnable(action);
-    }
-
-    @AfterTemplate
-    Runnable after(Runnable action) {
-      return action;
-    }
-  }
-
-  @SuppressWarnings("NoFunctionalReturnType")
-  static final class UnnecessaryPredicateConversion<T> {
-    @BeforeTemplate
-    java.util.function.Predicate<? extends T> before(
-        @CanTransformToTargetType Predicate<? extends T> predicate) {
-      return RxJavaReactorMigrationUtil.toJdkPredicate(predicate);
-    }
-
-    @AfterTemplate
-    java.util.function.Predicate<? extends T> after(
-        java.util.function.Predicate<? extends T> predicate) {
-      return predicate;
-    }
-  }
-
-  static final class FlowableBiFunctionRemoveUtil<T, U, R> {
-    @BeforeTemplate
-    Flowable<R> before(
-        Publisher<? extends T> source1,
-        Publisher<? extends U> source2,
-        @CanTransformToTargetType BiFunction<? super T, ? super U, ? extends R> zipper) {
-      return RxJava2Adapter.fluxToFlowable(
-          Flux.<T, U, R>zip(source1, source2, RxJavaReactorMigrationUtil.toJdkBiFunction(zipper)));
-    }
-
-    @AfterTemplate
-    Flowable<R> after(
-        Publisher<? extends T> source1,
-        Publisher<? extends U> source2,
-        java.util.function.BiFunction<? super T, ? super U, ? extends R> zipper) {
-      return RxJava2Adapter.fluxToFlowable(Flux.<T, U, R>zip(source1, source2, zipper));
-    }
-  }
-
-  ///////////////////////////////////////////
-  //////////// ASSORTED TEMPLATES ///////////
-  ///////////////////////////////////////////
-
-  static final class MonoFromNestedPublisher<T> {
-    @BeforeTemplate
-    Mono<T> before(Flux<T> flux) {
-      return Mono.from(RxJava2Adapter.fluxToFlowable(flux));
-    }
-
-    @AfterTemplate
-    Mono<T> after(Flux<T> flux) {
-      return Mono.from(flux);
-    }
-  }
-
-  static final class FlowableToFluxWithFilter<T> {
-    @BeforeTemplate
-    Flux<T> before(Flux<T> flux, Predicate<T> predicate) {
-      return RxJava2Adapter.flowableToFlux(
-          flux.filter(RxJavaReactorMigrationUtil.toJdkPredicate(predicate))
-              .as(RxJava2Adapter::fluxToFlowable));
-    }
-
-    @AfterTemplate
-    Flux<T> after(Flux<T> flux, Predicate<T> predicate) {
-      return flux.filter(RxJavaReactorMigrationUtil.toJdkPredicate(predicate));
-    }
-  }
-
-  static final class ObservableToFlux<T> {
-    @BeforeTemplate
-    Flux<T> before(Flux<T> flux, Predicate<T> predicate, BackpressureStrategy strategy) {
-      return RxJava2Adapter.observableToFlux(
-          RxJava2Adapter.fluxToObservable(flux).filter(predicate), strategy);
-    }
-
-    @AfterTemplate
-    Flux<T> after(Flux<T> flux, Predicate<T> predicate, BackpressureStrategy strategy) {
-      return flux.filter(RxJavaReactorMigrationUtil.toJdkPredicate(predicate));
-    }
-  }
-
-  static final class MonoFromToFlowableToFlux<T> {
-    @BeforeTemplate
-    Flux<T> before(Mono<T> mono) {
-      return RxJava2Adapter.flowableToFlux(mono.as(RxJava2Adapter::monoToFlowable));
-    }
-
-    @AfterTemplate
-    Flux<T> after(Mono<T> mono) {
-      return mono.flux();
-    }
-  }
-
-  static final class MonoThenThen<T> {
-    @BeforeTemplate
-    Mono<T> before(Mono<T> mono, Mono<T> other) {
-      return mono.then().then(other);
-    }
-
-    @AfterTemplate
-    Mono<T> after(Mono<T> mono, Mono<T> other) {
-      return mono.then(other);
-    }
-  }
-
-  // XXX: Find out how we can use this in the future.
-  //  static final class RemoveRedundantCast<T> {
-  //    @BeforeTemplate
-  //    T before(T object) {
-  //      return (T) object;
-  //    }
-  //
-  //    @AfterTemplate
-  //    T after(T object) {
-  //      return object;
-  //    }
-  //  }
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJavaUnwrapTemplates.java

@@ -1,404 +0,0 @@
-package tech.picnic.errorprone.refastertemplates;
-
-import com.google.errorprone.refaster.Refaster;
-import com.google.errorprone.refaster.annotation.AfterTemplate;
-import com.google.errorprone.refaster.annotation.BeforeTemplate;
-import com.google.errorprone.refaster.annotation.MayOptionallyUse;
-import com.google.errorprone.refaster.annotation.Placeholder;
-import io.reactivex.Completable;
-import io.reactivex.CompletableSource;
-import io.reactivex.Maybe;
-import io.reactivex.MaybeSource;
-import io.reactivex.Single;
-import io.reactivex.SingleSource;
-import io.reactivex.functions.Function;
-import org.reactivestreams.Publisher;
-import reactor.adapter.rxjava.RxJava2Adapter;
-import reactor.core.publisher.Mono;
-import tech.picnic.errorprone.migration.util.RxJavaReactorMigrationUtil;
-
-public final class RxJavaUnwrapTemplates {
-  private RxJavaUnwrapTemplates() {}
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class FlowableConcatMapCompletableUnwrapLambda<T> {
-    @Placeholder
-    abstract Mono<?> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<? super T, ? extends Publisher<?>> before() {
-      return e ->
-          RxJava2Adapter.completableToMono(
-              RxJavaReactorMigrationUtil.toJdkFunction(
-                      (T ident) -> RxJava2Adapter.monoToCompletable(placeholder(ident)))
-                  .apply(e));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<T, ? extends Publisher<?>> after() {
-      return v -> placeholder(v);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class MaybeFlatMapUnwrapLambda<I, T extends I, O> {
-    @Placeholder
-    abstract Mono<? extends O> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    @SuppressWarnings("unchecked")
-    java.util.function.Function<? super T, ? extends Mono<? extends O>> before() {
-      return Refaster.anyOf(
-          v ->
-              RxJava2Adapter.maybeToMono(
-                  (Maybe<O>)
-                      RxJavaReactorMigrationUtil.toJdkFunction(
-                              (T ident) -> RxJava2Adapter.monoToMaybe(placeholder(ident)))
-                          .apply(v)),
-          v ->
-              RxJava2Adapter.maybeToMono(
-                  RxJavaReactorMigrationUtil.toJdkFunction(
-                          (T ident) -> RxJava2Adapter.monoToMaybe(placeholder(ident)))
-                      .apply(v)));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<? super T, ? extends Mono<? extends O>> after() {
-      return v -> placeholder(v);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class MaybeFlatMapSingleElementUnwrapLambda<T, R> {
-    @Placeholder
-    abstract Mono<R> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<T, ? extends Mono<? extends R>> before() {
-      return Refaster.anyOf(
-          e ->
-              RxJava2Adapter.singleToMono(
-                  Single.wrap(
-                      RxJavaReactorMigrationUtil.toJdkFunction(
-                              (Function<T, SingleSource<R>>)
-                                  (T ident) -> RxJava2Adapter.monoToSingle(placeholder(ident)))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.singleToMono(
-                  Single.wrap(
-                      RxJavaReactorMigrationUtil.<T, SingleSource<R>>toJdkFunction(
-                              (T ident) -> RxJava2Adapter.monoToSingle(placeholder(ident)))
-                          .apply(e))));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<T, ? extends Mono<? extends R>> after() {
-      return e -> placeholder(e);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class SingleFlatMapMaybeUnwrapLambda<T, R> {
-    @Placeholder
-    abstract Mono<R> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<? super T, ? extends Mono<? extends R>> before() {
-      return Refaster.anyOf(
-          e ->
-              RxJava2Adapter.maybeToMono(
-                  Maybe.wrap(
-                      RxJavaReactorMigrationUtil.toJdkFunction(
-                              (Function<T, MaybeSource<R>>)
-                                  (T ident) -> RxJava2Adapter.monoToMaybe(placeholder(ident)))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.maybeToMono(
-                  Maybe.wrap(
-                      RxJavaReactorMigrationUtil.toJdkFunction(
-                              (Function<T, MaybeSource<R>>)
-                                  ident -> RxJava2Adapter.monoToMaybe(placeholder(ident)))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.maybeToMono(
-                  Maybe.wrap(
-                      RxJavaReactorMigrationUtil.<T, MaybeSource<R>>toJdkFunction(
-                              ident -> RxJava2Adapter.monoToMaybe(placeholder(ident)))
-                          .apply(e))));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<? super T, ? extends Mono<? extends R>> after() {
-      return e -> placeholder(e);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings({"NoFunctionalReturnType", "unchecked"})
-  abstract static class SingleOnResumeUnwrapLambda<T, R> {
-    @Placeholder
-    abstract Mono<? extends R> placeholder(@MayOptionallyUse Throwable input);
-
-    @BeforeTemplate
-    java.util.function.Function<? extends Throwable, ? extends Mono<? extends R>> before() {
-      return Refaster.anyOf(
-          e ->
-              RxJava2Adapter.singleToMono(
-                  RxJavaReactorMigrationUtil.toJdkFunction(
-                          ident -> RxJava2Adapter.monoToSingle(placeholder(e)))
-                      .apply(e)),
-          e ->
-              RxJava2Adapter.singleToMono(
-                  Single.wrap(
-                      RxJavaReactorMigrationUtil.toJdkFunction(
-                              (Function<Throwable, ? extends SingleSource<? extends R>>)
-                                  placeholder(e))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.singleToMono(
-                  Single.wrap(
-                      RxJavaReactorMigrationUtil.<Throwable, SingleSource<R>>toJdkFunction(
-                              (Function<Throwable, SingleSource<R>>) placeholder(e))
-                          .apply(e))));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<Throwable, ? extends Mono<? extends R>> after() {
-      return v -> placeholder(v);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class FlowableConcatMapMaybeDelayErrorUnwrapLambda<T, R> {
-    @Placeholder
-    abstract Mono<R> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<? super T, ? extends Publisher<? extends R>> after() {
-      return Refaster.anyOf(
-          e ->
-              Maybe.wrap(
-                      RxJavaReactorMigrationUtil.toJdkFunction(
-                              (Function<T, MaybeSource<R>>)
-                                  ident -> RxJava2Adapter.monoToMaybe(placeholder(ident)))
-                          .apply(e))
-                  .toFlowable(),
-          e ->
-              Maybe.wrap(
-                      RxJavaReactorMigrationUtil.<T, MaybeSource<R>>toJdkFunction(
-                              ident -> RxJava2Adapter.monoToMaybe(placeholder(ident)))
-                          .apply(e))
-                  .toFlowable());
-    }
-
-    @AfterTemplate
-    java.util.function.Function<? super T, ? extends Publisher<? extends R>> before() {
-      return e -> placeholder(e);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class FlowableFlatMapCompletableUnwrapLambda<T> {
-    @Placeholder
-    abstract Mono<?> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<T, ? extends Publisher<? extends Void>> before() {
-      return Refaster.anyOf(
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, Completable>toJdkFunction(
-                              (Function<T, Completable>)
-                                  (T ident) -> RxJava2Adapter.monoToCompletable(placeholder(ident)))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.completableToMono(
-                  RxJavaReactorMigrationUtil.<T, Completable>toJdkFunction(
-                          (Function<T, Completable>)
-                              (T ident) -> RxJava2Adapter.monoToCompletable(placeholder(ident)))
-                      .apply(e)),
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, Completable>toJdkFunction(
-                              (T ident) -> RxJava2Adapter.monoToCompletable(placeholder(ident)))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.completableToMono(
-                  RxJavaReactorMigrationUtil.<T, Completable>toJdkFunction(
-                          (T ident) -> RxJava2Adapter.monoToCompletable(placeholder(ident)))
-                      .apply(e)));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<T, Mono<?>> after() {
-      return v -> placeholder(v);
-    }
-  }
-
-  // XXX: Improve naming and add test case
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class FlowableUnwrapLambda<T> {
-    @Placeholder
-    abstract Completable placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<T, Publisher<? extends Void>> before() {
-      return Refaster.anyOf(
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, CompletableSource>toJdkFunction(
-                              (Function<T, CompletableSource>) v -> placeholder(v))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, CompletableSource>toJdkFunction(
-                              v -> placeholder(v))
-                          .apply(e))));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<T, Mono<? extends Void>> after() {
-      return v -> RxJava2Adapter.completableToMono(Completable.wrap(placeholder(v)));
-    }
-  }
-
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class FlowableFlatMapUnwrapLambda<T> {
-    @Placeholder
-    abstract CompletableSource placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<T, ? extends Publisher<? extends Void>> before() {
-      return e ->
-          RxJava2Adapter.completableToMono(
-              Completable.wrap(
-                  RxJavaReactorMigrationUtil.<T, CompletableSource>toJdkFunction(
-                          (Function<T, CompletableSource>) v -> placeholder(v))
-                      .apply(e)));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<T, Mono<? extends Void>> after() {
-      return v -> RxJava2Adapter.completableToMono(Completable.wrap(placeholder(v)));
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class SingleFlatMapUnwrapLambda<T, R> {
-    @Placeholder
-    abstract Mono<? extends R> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<T, ? extends Mono<? extends R>> before() {
-      return v ->
-          RxJava2Adapter.singleToMono(
-              (Single<? extends R>)
-                  RxJavaReactorMigrationUtil.toJdkFunction(
-                          (T ident) -> RxJava2Adapter.monoToSingle(placeholder(ident)))
-                      .apply(v));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<T, ? extends Mono<? extends R>> after() {
-      return v -> placeholder(v);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class SingleRemoveLambdaWithCast<T> {
-    @Placeholder
-    abstract Mono<?> placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<? super T, ? extends Publisher<? extends Void>> before() {
-      return Refaster.anyOf(
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, Completable>toJdkFunction(
-                              (Function<T, Completable>)
-                                  v -> placeholder(v).as(RxJava2Adapter::monoToCompletable))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, Completable>toJdkFunction(
-                              (Function<T, Completable>)
-                                  v -> RxJava2Adapter.monoToCompletable(placeholder(v)))
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, Completable>toJdkFunction(
-                              v -> RxJava2Adapter.monoToCompletable(placeholder(v)))
-                          .apply(e))));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<? super T, ? extends Mono<?>> after() {
-      return v -> placeholder(v);
-    }
-  }
-
-  // XXX: Add test
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class SingleRemoveLambdaWithCompletable<T> {
-    @BeforeTemplate
-    java.util.function.Function<? super T, ? extends Mono<? extends Void>> before(
-        Completable completable) {
-      return Refaster.anyOf(
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, CompletableSource>toJdkFunction(
-                              (Function<T, CompletableSource>) v -> completable)
-                          .apply(e))),
-          e ->
-              RxJava2Adapter.completableToMono(
-                  Completable.wrap(
-                      RxJavaReactorMigrationUtil.<T, CompletableSource>toJdkFunction(
-                              v -> completable)
-                          .apply(e))));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<? super T, ? extends Mono<? extends Void>> after(
-        Completable completable) {
-      return v -> RxJava2Adapter.completableToMono(completable);
-    }
-  }
-
-  // XXX: Verify if this template still flags other cases than the one above.
-  @SuppressWarnings("NoFunctionalReturnType")
-  abstract static class SingleRemoveLambdaWithCompletableExtra<T> {
-    @Placeholder
-    abstract Completable placeholder(@MayOptionallyUse T input);
-
-    @BeforeTemplate
-    java.util.function.Function<? super T, ? extends Mono<? extends Void>> before() {
-      return e ->
-          RxJava2Adapter.completableToMono(
-              Completable.wrap(
-                  RxJavaReactorMigrationUtil.<T, CompletableSource>toJdkFunction(
-                          (Function<T, CompletableSource>) v -> placeholder(v))
-                      .apply(e)));
-    }
-
-    @AfterTemplate
-    java.util.function.Function<? super T, ? extends Mono<? extends Void>> after() {
-      return v -> RxJava2Adapter.completableToMono(placeholder(v));
-    }
-  }
-}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/StreamTemplates.java

@@ -1,11 +1,12 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Comparator.reverseOrder;
 import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.joining;
 
 import com.google.common.collect.Streams;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -18,12 +19,31 @@ import java.util.Objects;
 import java.util.Optional;
 import java.util.function.Function;
 import java.util.function.Predicate;
+import java.util.stream.Collector;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
 
 /** Refaster templates related to expressions dealing with {@link Stream}s. */
 final class StreamTemplates {
   private StreamTemplates() {}
 
+  /**
+   * Prefer {@link Collectors#joining()} over {@link Collectors#joining(CharSequence)} with an empty
+   * delimiter string.
+   */
+  static final class Joining {
+    @BeforeTemplate
+    Collector<CharSequence, ?, String> before() {
+      return joining("");
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    Collector<CharSequence, ?, String> after() {
+      return joining();
+    }
+  }
+
   /** Prefer {@link Stream#empty()} over less clear alternatives. */
   static final class EmptyStream<T> {
     @BeforeTemplate
@@ -216,7 +236,7 @@ final class StreamTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Optional<T> after(Stream<T> stream) {
       return stream.min(naturalOrder());
     }
@@ -242,7 +262,7 @@ final class StreamTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Optional<T> after(Stream<T> stream) {
       return stream.max(naturalOrder());
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/StringTemplates.java

@@ -14,6 +14,7 @@ import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Optional;
+import javax.annotation.Nullable;
 
 /** Refaster templates related to expressions dealing with {@link String}s. */
 // XXX: Should we prefer `s -> !s.isEmpty()` or `not(String::isEmpty)`?
@@ -37,7 +38,7 @@ final class StringTemplates {
   /** Prefer {@link Strings#isNullOrEmpty(String)} over the more verbose alternative. */
   static final class StringIsNullOrEmpty {
     @BeforeTemplate
-    boolean before(String str) {
+    boolean before(@Nullable String str) {
       return str == null || str.isEmpty();
     }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/TestNGToAssertJTemplates.java

@@ -1,5 +1,6 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.assertj.core.api.Assertions.fail;
@@ -17,7 +18,6 @@ import static org.testng.Assert.assertTrue;
 
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.annotations.DoNotCall;
-import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
@@ -96,7 +96,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(String message) {
       fail(message);
     }
@@ -110,7 +110,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(String message, Throwable throwable) {
       fail(message, throwable);
     }
@@ -123,7 +123,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(boolean condition) {
       assertThat(condition).isTrue();
     }
@@ -136,7 +136,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(boolean condition, String message) {
       assertThat(condition).withFailMessage(message).isTrue();
     }
@@ -149,7 +149,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(boolean condition) {
       assertThat(condition).isFalse();
     }
@@ -162,7 +162,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(boolean condition, String message) {
       assertThat(condition).withFailMessage(message).isFalse();
     }
@@ -175,7 +175,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object object) {
       assertThat(object).isNull();
     }
@@ -188,7 +188,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object object, String message) {
       assertThat(object).withFailMessage(message).isNull();
     }
@@ -201,7 +201,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object object) {
       assertThat(object).isNotNull();
     }
@@ -214,7 +214,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object object, String message) {
       assertThat(object).withFailMessage(message).isNotNull();
     }
@@ -227,7 +227,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected) {
       assertThat(actual).isSameAs(expected);
     }
@@ -240,7 +240,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected, String message) {
       assertThat(actual).withFailMessage(message).isSameAs(expected);
     }
@@ -253,7 +253,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected) {
       assertThat(actual).isNotSameAs(expected);
     }
@@ -266,7 +266,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected, String message) {
       assertThat(actual).withFailMessage(message).isNotSameAs(expected);
     }
@@ -329,7 +329,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected) {
       assertThat(actual).isEqualTo(expected);
     }
@@ -392,7 +392,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected, String message) {
       assertThat(actual).withFailMessage(message).isEqualTo(expected);
     }
@@ -405,7 +405,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(float actual, float expected, float delta) {
       assertThat(actual).isCloseTo(expected, offset(delta));
     }
@@ -418,7 +418,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(float actual, float expected, float delta, String message) {
       assertThat(actual).withFailMessage(message).isCloseTo(expected, offset(delta));
     }
@@ -431,7 +431,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(double actual, double expected, double delta) {
       assertThat(actual).isCloseTo(expected, offset(delta));
     }
@@ -444,7 +444,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(double actual, double expected, double delta, String message) {
       assertThat(actual).withFailMessage(message).isCloseTo(expected, offset(delta));
     }
@@ -497,7 +497,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object[] actual, Object[] expected) {
       assertThat(actual).containsExactly(expected);
     }
@@ -550,7 +550,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object[] actual, Object[] expected, String message) {
       assertThat(actual).withFailMessage(message).containsExactly(expected);
     }
@@ -563,7 +563,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object[] actual, Object[] expected) {
       assertThat(actual).containsExactlyInAnyOrder(expected);
     }
@@ -576,7 +576,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object[] actual, Object[] expected, String message) {
       assertThat(actual).withFailMessage(message).containsExactlyInAnyOrder(expected);
     }
@@ -589,7 +589,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     <S, T extends S> void after(Iterator<S> actual, Iterator<T> expected) {
       // XXX: This is not `null`-safe.
       // XXX: The `ImmutableList.copyOf` should actually *not* be imported statically.
@@ -604,7 +604,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     <S, T extends S> void after(Iterator<S> actual, Iterator<T> expected, String message) {
       // XXX: This is not `null`-safe.
       // XXX: The `ImmutableList.copyOf` should actually *not* be imported statically.
@@ -629,7 +629,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     <S, T extends S> void after(Iterable<S> actual, Iterable<T> expected) {
       assertThat(actual).containsExactlyElementsOf(expected);
     }
@@ -647,7 +647,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     <S, T extends S> void after(Iterable<S> actual, Iterable<T> expected, String message) {
       assertThat(actual).withFailMessage(message).containsExactlyElementsOf(expected);
     }
@@ -660,7 +660,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     <S, T extends S> void after(Set<S> actual, Set<T> expected) {
       assertThat(actual).hasSameElementsAs(expected);
     }
@@ -673,7 +673,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     <S, T extends S> void after(Set<S> actual, Set<T> expected, String message) {
       assertThat(actual).withFailMessage(message).hasSameElementsAs(expected);
     }
@@ -741,7 +741,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected) {
       assertThat(actual).isNotEqualTo(expected);
     }
@@ -809,7 +809,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(Object actual, Object expected, String message) {
       assertThat(actual).withFailMessage(message).isNotEqualTo(expected);
     }
@@ -822,7 +822,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(float actual, float expected, float delta) {
       assertThat(actual).isNotCloseTo(expected, offset(delta));
     }
@@ -835,7 +835,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(float actual, float expected, float delta, String message) {
       assertThat(actual).withFailMessage(message).isNotCloseTo(expected, offset(delta));
     }
@@ -848,7 +848,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(double actual, double expected, double delta) {
       assertThat(actual).isNotCloseTo(expected, offset(delta));
     }
@@ -861,7 +861,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(double actual, double expected, double delta, String message) {
       assertThat(actual).withFailMessage(message).isNotCloseTo(expected, offset(delta));
     }
@@ -874,7 +874,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(ThrowingCallable runnable) {
       assertThatThrownBy(runnable);
     }
@@ -887,7 +887,7 @@ final class TestNGToAssertJTemplates {
     }
 
     @AfterTemplate
-    @UseImportPolicy(ImportPolicy.STATIC_IMPORT_ALWAYS)
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after(ThrowingCallable runnable, Class<T> clazz) {
       assertThatThrownBy(runnable).isInstanceOf(clazz);
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/TimeTemplates.java

@@ -1,5 +1,7 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static java.time.ZoneOffset.UTC;
+
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.AlsoNegation;
@@ -17,6 +19,7 @@ import java.time.ZoneOffset;
 import java.time.chrono.ChronoLocalDate;
 import java.time.chrono.ChronoLocalDateTime;
 import java.time.chrono.ChronoZonedDateTime;
+import java.time.temporal.ChronoUnit;
 import java.time.temporal.TemporalUnit;
 
 /** Refaster templates related to expressions dealing with time. */
@@ -49,13 +52,26 @@ final class TimeTemplates {
           ZoneId.of("UTC"),
           ZoneId.of("+0"),
           ZoneId.of("-0"),
-          ZoneOffset.UTC.normalized(),
-          ZoneId.from(ZoneOffset.UTC));
+          UTC.normalized(),
+          ZoneId.from(UTC));
     }
 
     @AfterTemplate
     ZoneOffset after() {
-      return ZoneOffset.UTC;
+      return UTC;
+    }
+  }
+
+  /** Prefer {@link Instant#atOffset(ZoneOffset)} over the more verbose alternative. */
+  static final class InstantAtOffset {
+    @BeforeTemplate
+    OffsetDateTime before(Instant instant, ZoneOffset zoneOffset) {
+      return OffsetDateTime.ofInstant(instant, zoneOffset);
+    }
+
+    @AfterTemplate
+    OffsetDateTime after(Instant instant, ZoneOffset zoneOffset) {
+      return instant.atOffset(zoneOffset);
     }
   }
 
@@ -64,7 +80,7 @@ final class TimeTemplates {
     @BeforeTemplate
     @SuppressWarnings("TimeZoneUsage")
     Clock before() {
-      return Clock.system(ZoneOffset.UTC);
+      return Clock.system(UTC);
     }
 
     @AfterTemplate
@@ -310,8 +326,86 @@ final class TimeTemplates {
     }
   }
 
+  /** Prefer {@link Duration#ofDays(long)} over alternative representations. */
+  static final class DurationOfDays {
+    @BeforeTemplate
+    Duration before(long amount) {
+      return Duration.of(amount, ChronoUnit.DAYS);
+    }
+
+    @AfterTemplate
+    Duration after(long amount) {
+      return Duration.ofDays(amount);
+    }
+  }
+
+  /** Prefer {@link Duration#ofHours(long)} over alternative representations. */
+  static final class DurationOfHours {
+    @BeforeTemplate
+    Duration before(long amount) {
+      return Duration.of(amount, ChronoUnit.HOURS);
+    }
+
+    @AfterTemplate
+    Duration after(long amount) {
+      return Duration.ofHours(amount);
+    }
+  }
+
+  /** Prefer {@link Duration#ofMillis(long)} over alternative representations. */
+  static final class DurationOfMillis {
+    @BeforeTemplate
+    Duration before(long amount) {
+      return Duration.of(amount, ChronoUnit.MILLIS);
+    }
+
+    @AfterTemplate
+    Duration after(long amount) {
+      return Duration.ofMillis(amount);
+    }
+  }
+
+  /** Prefer {@link Duration#ofMinutes(long)} over alternative representations. */
+  static final class DurationOfMinutes {
+    @BeforeTemplate
+    Duration before(long amount) {
+      return Duration.of(amount, ChronoUnit.MINUTES);
+    }
+
+    @AfterTemplate
+    Duration after(long amount) {
+      return Duration.ofMinutes(amount);
+    }
+  }
+
+  /** Prefer {@link Duration#ofNanos(long)} over alternative representations. */
+  static final class DurationOfNanos {
+    @BeforeTemplate
+    Duration before(long amount) {
+      return Duration.of(amount, ChronoUnit.NANOS);
+    }
+
+    @AfterTemplate
+    Duration after(long amount) {
+      return Duration.ofNanos(amount);
+    }
+  }
+
+  /** Prefer {@link Duration#ofSeconds(long)} over alternative representations. */
+  static final class DurationOfSeconds {
+    @BeforeTemplate
+    Duration before(long amount) {
+      return Duration.of(amount, ChronoUnit.SECONDS);
+    }
+
+    @AfterTemplate
+    Duration after(long amount) {
+      return Duration.ofSeconds(amount);
+    }
+  }
+
   /**
-   * Don't unnecessarily convert two and from milliseconds. (This way nanosecond precision is
+   * Don't unnecessarily convert to and from milliseconds. (This way nanosecond precision is
    * retained.)
    *
    * <p><strong>Warning:</strong> this rewrite rule increases precision!
@@ -329,7 +423,7 @@ final class TimeTemplates {
   }
 
   /**
-   * Don't unnecessarily convert two and from milliseconds. (This way nanosecond precision is
+   * Don't unnecessarily convert to and from milliseconds. (This way nanosecond precision is
    * retained.)
    *
    * <p><strong>Warning:</strong> this rewrite rule increases precision!

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/WebClientTemplates.java

@@ -1,12 +1,25 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static org.springframework.http.HttpMethod.GET;
+import static org.springframework.http.HttpMethod.HEAD;
+import static org.springframework.http.HttpMethod.OPTIONS;
+import static org.springframework.http.HttpMethod.PATCH;
+import static org.springframework.http.HttpMethod.POST;
+import static org.springframework.http.HttpMethod.PUT;
 import static org.springframework.web.reactive.function.BodyInserters.fromValue;
 
+import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.Repeated;
+import java.util.function.Function;
+import org.springframework.http.HttpMethod;
 import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.reactive.function.client.WebClient.RequestBodySpec;
+import org.springframework.web.reactive.function.client.WebClient.RequestBodyUriSpec;
 import org.springframework.web.reactive.function.client.WebClient.RequestHeadersSpec;
+import org.springframework.web.reactive.function.client.WebClient.RequestHeadersUriSpec;
 
 /**
  * Refaster templates related to expressions dealing with {@link
@@ -23,7 +36,7 @@ final class WebClientTemplates {
     }
 
     @BeforeTemplate
-    WebTestClient.RequestHeadersSpec<?> before2(
+    WebTestClient.RequestHeadersSpec<?> before(
         WebTestClient.RequestBodySpec requestBodySpec, T value) {
       return requestBodySpec.body(fromValue(value));
     }
@@ -33,4 +46,159 @@ final class WebClientTemplates {
       return requestBodySpec.bodyValue(value);
     }
   }
+
+  /**
+   * Prefer {@link WebClient#get()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#GET}.
+   */
+  static final class WebClientGet {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(WebClient webClient) {
+      return webClient.method(GET);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(WebTestClient webClient) {
+      return webClient.method(GET);
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(WebClient webClient) {
+      return webClient.get();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#head()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#HEAD}.
+   */
+  static final class WebClientHead {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(WebClient webClient) {
+      return webClient.method(HEAD);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(WebTestClient webClient) {
+      return webClient.method(HEAD);
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(WebClient webClient) {
+      return webClient.head();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#options()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#OPTIONS}.
+   */
+  static final class WebClientOptions {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(WebClient webClient) {
+      return webClient.method(OPTIONS);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(WebTestClient webClient) {
+      return webClient.method(OPTIONS);
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(WebClient webClient) {
+      return webClient.options();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#patch()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#PATCH}.
+   */
+  static final class WebClientPatch {
+    @BeforeTemplate
+    RequestBodyUriSpec before(WebClient webClient) {
+      return webClient.method(PATCH);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestBodyUriSpec before(WebTestClient webClient) {
+      return webClient.method(PATCH);
+    }
+
+    @AfterTemplate
+    RequestBodyUriSpec after(WebClient webClient) {
+      return webClient.patch();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#post()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#POST}.
+   */
+  static final class WebClientPost {
+    @BeforeTemplate
+    RequestBodyUriSpec before(WebClient webClient) {
+      return webClient.method(POST);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestBodyUriSpec before(WebTestClient webClient) {
+      return webClient.method(POST);
+    }
+
+    @AfterTemplate
+    RequestBodyUriSpec after(WebClient webClient) {
+      return webClient.post();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#put()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#PUT}.
+   */
+  static final class WebClientPut {
+    @BeforeTemplate
+    RequestBodyUriSpec before(WebClient webClient) {
+      return webClient.method(PUT);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestBodyUriSpec before(WebTestClient webClient) {
+      return webClient.method(PUT);
+    }
+
+    @AfterTemplate
+    RequestBodyUriSpec after(WebClient webClient) {
+      return webClient.put();
+    }
+  }
+
+  /** Don't unnecessarily use {@link RequestHeadersUriSpec#uri(Function)}. */
+  abstract static class RequestHeadersUriSpecUri {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(
+        RequestHeadersUriSpec<?> requestHeadersUriSpec,
+        String path,
+        @Repeated Object uriVariables) {
+      return requestHeadersUriSpec.uri(
+          uriBuilder -> uriBuilder.path(path).build(Refaster.asVarargs(uriVariables)));
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(
+        WebTestClient.RequestHeadersUriSpec<?> requestHeadersUriSpec,
+        String path,
+        @Repeated Object uriVariables) {
+      return requestHeadersUriSpec.uri(
+          uriBuilder -> uriBuilder.path(path).build(Refaster.asVarargs(uriVariables)));
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(
+        RequestHeadersUriSpec<?> requestHeadersUriSpec,
+        String path,
+        @Repeated Object uriVariables) {
+      return requestHeadersUriSpec.uri(path, Refaster.asVarargs(uriVariables));
+    }
+  }
 }

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/AmbiguousJsonCreatorTest.java

@@ -6,14 +6,14 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-final class AmbiguousJsonCreatorCheckTest {
+final class AmbiguousJsonCreatorTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(AmbiguousJsonCreatorCheck.class, getClass())
+      CompilationTestHelper.newInstance(AmbiguousJsonCreator.class, getClass())
           .expectErrorMessage(
               "X",
               containsPattern("`JsonCreator.Mode` should be set for single-argument creators"));
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(AmbiguousJsonCreatorCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(AmbiguousJsonCreator.class, getClass());
 
   @Test
   void identification() {
@@ -112,7 +112,6 @@ final class AmbiguousJsonCreatorCheckTest {
             "      return new F(s);",
             "    }",
             "  }",
-            "",
             "}")
         .doTest();
   }

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/AssertJIsNullTest.java

@@ -0,0 +1,64 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class AssertJIsNullTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(AssertJIsNull.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(AssertJIsNull.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    assertThat(1).isEqualTo(1);",
+            "    // BUG: Diagnostic contains:",
+            "    assertThat(1).isEqualTo(null);",
+            "    // BUG: Diagnostic contains:",
+            "    assertThat(\"foo\").isEqualTo(null);",
+            "    isEqualTo(null);",
+            "  }",
+            "",
+            "  private boolean isEqualTo(Object value) {",
+            "    return value.equals(\"bar\");",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    assertThat(1).isEqualTo(null);",
+            "    assertThat(\"foo\").isEqualTo(null);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    assertThat(1).isNull();",
+            "    assertThat(\"foo\").isNull();",
+            "  }",
+            "}")
+        .doTest(TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/AutowiredConstructorTest.java

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class AutowiredConstructorCheckTest {
+final class AutowiredConstructorTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(AutowiredConstructorCheck.class, getClass());
+      CompilationTestHelper.newInstance(AutowiredConstructor.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(AutowiredConstructorCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(AutowiredConstructor.class, getClass());
 
   @Test
   void identification() {
@@ -27,27 +27,34 @@ public final class AutowiredConstructorCheckTest {
             "  }",
             "",
             "  class B {",
-            "    @Autowired void setProperty(Object o) {}",
+            "    @Autowired",
+            "    void setProperty(Object o) {}",
             "  }",
             "",
             "  class C {",
             "    // BUG: Diagnostic contains:",
-            "    @Autowired C() {}",
+            "    @Autowired",
+            "    C() {}",
             "  }",
             "",
             "  class D {",
             "    // BUG: Diagnostic contains:",
-            "    @Autowired D(String x) {}",
+            "    @Autowired",
+            "    D(String x) {}",
             "  }",
             "",
             "  class E {",
-            "    @Autowired E() {}",
+            "    @Autowired",
+            "    E() {}",
+            "",
             "    E(String x) {}",
             "  }",
             "",
             "  class F {",
             "    F() {}",
-            "    @Autowired F(String x) {}",
+            "",
+            "    @Autowired",
+            "    F(String x) {}",
             "  }",
             "",
             "  class G {",
@@ -55,7 +62,8 @@ public final class AutowiredConstructorCheckTest {
             "  }",
             "",
             "  class H {",
-            "    @SafeVarargs H(List<String>... lists) {}",
+            "    @SafeVarargs",
+            "    H(List<String>... lists) {}",
             "  }",
             "}")
         .doTest();
@@ -70,11 +78,14 @@ public final class AutowiredConstructorCheckTest {
             "",
             "interface Container {",
             "  class A {",
-            "    @Autowired @Deprecated A() {}",
+            "    @Autowired",
+            "    @Deprecated",
+            "    A() {}",
             "  }",
             "",
             "  class B {",
-            "    @Autowired B(String x) {}",
+            "    @Autowired",
+            "    B(String x) {}",
             "  }",
             "}")
         .addOutputLines(
@@ -83,10 +94,13 @@ public final class AutowiredConstructorCheckTest {
             "",
             "interface Container {",
             "  class A {",
-            "    @Deprecated A() {}",
+            "",
+            "    @Deprecated",
+            "    A() {}",
             "  }",
             "",
             "  class B {",
+            "",
             "    B(String x) {}",
             "  }",
             "}")

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/CanonicalAnnotationSyntaxCheckTest.java

@@ -1,156 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import com.google.errorprone.BugCheckerRefactoringTestHelper;
-import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
-import com.google.errorprone.CompilationTestHelper;
-import org.junit.jupiter.api.Test;
-
-public final class CanonicalAnnotationSyntaxCheckTest {
-  private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(CanonicalAnnotationSyntaxCheck.class, getClass());
-  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(CanonicalAnnotationSyntaxCheck.class, getClass());
-
-  @Test
-  void identification() {
-    compilationTestHelper
-        .addSourceLines(
-            "pkg/A.java",
-            "package pkg;",
-            "",
-            "import pkg.A.Foo;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    int[] value() default {};",
-            "    int[] value2() default {};",
-            "  }",
-            "",
-            "  @pkg.A.Foo A minimal1();",
-            "  @A.Foo A minimal2();",
-            "  @Foo A minimal3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo() A functional1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo() A functional2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo() A functional3();",
-            "",
-            "  @pkg.A.Foo(1) A simple1();",
-            "  @A.Foo(1) A simple2();",
-            "  @Foo(1) A simple3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo({1}) A singleton1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo({1}) A singleton2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({1}) A singleton3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo(value = 1) A verbose1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo(value = 1) A verbose2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(value = 1) A verbose3();",
-            "",
-            "  @pkg.A.Foo(value2 = 2) A custom1();",
-            "  @A.Foo(value2 = 2) A custom2();",
-            "  @Foo(value2 = 2) A custom3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo(value2 = {2}) A customSingleton1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo(value2 = {2}) A customSingleton2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(value2 = {2}) A customSingleton3();",
-            "",
-            "  @pkg.A.Foo(value2 = {2, 2}) A customPair1();",
-            "  @A.Foo(value2 = {2, 2}) A customPair2();",
-            "  @Foo(value2 = {2, 2}) A customPair3();",
-            "",
-            "  @pkg.A.Foo(value = 1, value2 = 2) A extended1();",
-            "  @A.Foo(value = 1, value2 = 2) A extended2();",
-            "  @Foo(value = 1, value2 = 2) A extended3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo({1, 1,}) A trailingComma1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo({1, 1,}) A trailingComma2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({1, 1,}) A trailingComma3();",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void replacement() {
-    refactoringTestHelper
-        .addInputLines(
-            "in/pkg/A.java",
-            "package pkg;",
-            "",
-            "import pkg.A.Foo;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] value2() default {};",
-            "  }",
-            "",
-            "  @pkg.A.Foo() A functional1();",
-            "  @A.Foo() A functional2();",
-            "  @Foo() A functional3();",
-            "",
-            "  @pkg.A.Foo(value = \"foo\") A verbose1();",
-            "  @A.Foo(value = \"a'b\") A verbose2();",
-            "  @Foo(value = \"a\" + \"\\nb\") A verbose3();",
-            "",
-            "  @pkg.A.Foo(value = {\"foo\"}) A moreVerbose1();",
-            "  @A.Foo(value = {\"a'b\"}) A moreVerbose2();",
-            "  @Foo(value = {\"a\" + \"\\nb\"}) A moreVerbose3();",
-            "",
-            "  @pkg.A.Foo(value = {\"foo\", \"bar\"}, value2 = {2}) A extended1();",
-            "  @A.Foo(value = {\"a'b\", \"c'd\"}, value2 = {2}) A extended2();",
-            "  @Foo(value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"}, value2 = {2}) A extended3();",
-            "",
-            "  @pkg.A.Foo({\"foo\", \"bar\",}) A trailingComma1();",
-            "  @A.Foo({\"a'b\", \"c'd\",}) A trailingComma2();",
-            "  @Foo({\"a\" + \"\\nb\", \"c\" + \"\\nd\",}) A trailingComma3();",
-            "}")
-        .addOutputLines(
-            "out/pkg/A.java",
-            "package pkg;",
-            "",
-            "import pkg.A.Foo;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] value2() default {};",
-            "  }",
-            "",
-            "  @pkg.A.Foo A functional1();",
-            "  @A.Foo A functional2();",
-            "  @Foo A functional3();",
-            "",
-            "  @pkg.A.Foo(\"foo\") A verbose1();",
-            "  @A.Foo(\"a'b\") A verbose2();",
-            "  @Foo(\"a\" + \"\\nb\") A verbose3();",
-            "",
-            "  @pkg.A.Foo(\"foo\") A moreVerbose1();",
-            "  @A.Foo(\"a'b\") A moreVerbose2();",
-            "  @Foo(\"a\" + \"\\nb\") A moreVerbose3();",
-            "",
-            "  @pkg.A.Foo(value = {\"foo\", \"bar\"}, value2 = 2) A extended1();",
-            "  @A.Foo(value = {\"a'b\", \"c'd\"}, value2 = 2) A extended2();",
-            "  @Foo(value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"}, value2 = 2) A extended3();",
-            "",
-            "  @pkg.A.Foo({\"foo\", \"bar\"}) A trailingComma1();",
-            "  @A.Foo({\"a'b\", \"c'd\"}) A trailingComma2();",
-            "  @Foo({\"a\" + \"\\nb\", \"c\" + \"\\nd\"}) A trailingComma3();",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/CanonicalAnnotationSyntaxTest.java

@@ -0,0 +1,274 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class CanonicalAnnotationSyntaxTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(CanonicalAnnotationSyntax.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(CanonicalAnnotationSyntax.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "pkg/A.java",
+            "package pkg;",
+            "",
+            "import pkg.A.Foo;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    int[] value() default {};",
+            "",
+            "    int[] value2() default {};",
+            "  }",
+            "",
+            "  @pkg.A.Foo",
+            "  A minimal1();",
+            "",
+            "  @A.Foo",
+            "  A minimal2();",
+            "",
+            "  @Foo",
+            "  A minimal3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo()",
+            "  A functional1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo()",
+            "  A functional2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo()",
+            "  A functional3();",
+            "",
+            "  @pkg.A.Foo(1)",
+            "  A simple1();",
+            "",
+            "  @A.Foo(1)",
+            "  A simple2();",
+            "",
+            "  @Foo(1)",
+            "  A simple3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo({1})",
+            "  A singleton1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo({1})",
+            "  A singleton2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({1})",
+            "  A singleton3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo(value = 1)",
+            "  A verbose1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo(value = 1)",
+            "  A verbose2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(value = 1)",
+            "  A verbose3();",
+            "",
+            "  @pkg.A.Foo(value2 = 2)",
+            "  A custom1();",
+            "",
+            "  @A.Foo(value2 = 2)",
+            "  A custom2();",
+            "",
+            "  @Foo(value2 = 2)",
+            "  A custom3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo(value2 = {2})",
+            "  A customSingleton1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo(value2 = {2})",
+            "  A customSingleton2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(value2 = {2})",
+            "  A customSingleton3();",
+            "",
+            "  @pkg.A.Foo(value2 = {2, 2})",
+            "  A customPair1();",
+            "",
+            "  @A.Foo(value2 = {2, 2})",
+            "  A customPair2();",
+            "",
+            "  @Foo(value2 = {2, 2})",
+            "  A customPair3();",
+            "",
+            "  @pkg.A.Foo(value = 1, value2 = 2)",
+            "  A extended1();",
+            "",
+            "  @A.Foo(value = 1, value2 = 2)",
+            "  A extended2();",
+            "",
+            "  @Foo(value = 1, value2 = 2)",
+            "  A extended3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo({",
+            "    1, 1,",
+            "  })",
+            "  A trailingComma1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo({",
+            "    1, 1,",
+            "  })",
+            "  A trailingComma2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({",
+            "    1, 1,",
+            "  })",
+            "  A trailingComma3();",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "in/pkg/A.java",
+            "package pkg;",
+            "",
+            "import pkg.A.Foo;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] value2() default {};",
+            "  }",
+            "",
+            "  @pkg.A.Foo()",
+            "  A functional1();",
+            "",
+            "  @A.Foo()",
+            "  A functional2();",
+            "",
+            "  @Foo()",
+            "  A functional3();",
+            "",
+            "  @pkg.A.Foo(value = \"foo\")",
+            "  A verbose1();",
+            "",
+            "  @A.Foo(value = \"a'b\")",
+            "  A verbose2();",
+            "",
+            "  @Foo(value = \"a\" + \"\\nb\")",
+            "  A verbose3();",
+            "",
+            "  @pkg.A.Foo(value = {\"foo\"})",
+            "  A moreVerbose1();",
+            "",
+            "  @A.Foo(value = {\"a'b\"})",
+            "  A moreVerbose2();",
+            "",
+            "  @Foo(value = {\"a\" + \"\\nb\"})",
+            "  A moreVerbose3();",
+            "",
+            "  @pkg.A.Foo(",
+            "      value = {\"foo\", \"bar\"},",
+            "      value2 = {2})",
+            "  A extended1();",
+            "",
+            "  @A.Foo(",
+            "      value = {\"a'b\", \"c'd\"},",
+            "      value2 = {2})",
+            "  A extended2();",
+            "",
+            "  @Foo(",
+            "      value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"},",
+            "      value2 = {2})",
+            "  A extended3();",
+            "",
+            "  @pkg.A.Foo({",
+            "    \"foo\", \"bar\",",
+            "  })",
+            "  A trailingComma1();",
+            "",
+            "  @A.Foo({",
+            "    \"a'b\", \"c'd\",",
+            "  })",
+            "  A trailingComma2();",
+            "",
+            "  @Foo({",
+            "    \"a\" + \"\\nb\",",
+            "    \"c\" + \"\\nd\",",
+            "  })",
+            "  A trailingComma3();",
+            "}")
+        .addOutputLines(
+            "out/pkg/A.java",
+            "package pkg;",
+            "",
+            "import pkg.A.Foo;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] value2() default {};",
+            "  }",
+            "",
+            "  @pkg.A.Foo",
+            "  A functional1();",
+            "",
+            "  @A.Foo",
+            "  A functional2();",
+            "",
+            "  @Foo",
+            "  A functional3();",
+            "",
+            "  @pkg.A.Foo(\"foo\")",
+            "  A verbose1();",
+            "",
+            "  @A.Foo(\"a'b\")",
+            "  A verbose2();",
+            "",
+            "  @Foo(\"a\" + \"\\nb\")",
+            "  A verbose3();",
+            "",
+            "  @pkg.A.Foo(\"foo\")",
+            "  A moreVerbose1();",
+            "",
+            "  @A.Foo(\"a'b\")",
+            "  A moreVerbose2();",
+            "",
+            "  @Foo(\"a\" + \"\\nb\")",
+            "  A moreVerbose3();",
+            "",
+            "  @pkg.A.Foo(",
+            "      value = {\"foo\", \"bar\"},",
+            "      value2 = 2)",
+            "  A extended1();",
+            "",
+            "  @A.Foo(",
+            "      value = {\"a'b\", \"c'd\"},",
+            "      value2 = 2)",
+            "  A extended2();",
+            "",
+            "  @Foo(",
+            "      value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"},",
+            "      value2 = 2)",
+            "  A extended3();",
+            "",
+            "  @pkg.A.Foo({\"foo\", \"bar\"})",
+            "  A trailingComma1();",
+            "",
+            "  @A.Foo({\"a'b\", \"c'd\"})",
+            "  A trailingComma2();",
+            "",
+            "  @Foo({\"a\" + \"\\nb\", \"c\" + \"\\nd\"})",
+            "  A trailingComma3();",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/CollectorMutabilityTest.java

@@ -0,0 +1,200 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers.SECOND;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class CollectorMutabilityTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(CollectorMutability.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(CollectorMutability.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "import static com.google.common.collect.ImmutableMap.toImmutableMap;",
+            "import static com.google.common.collect.ImmutableSet.toImmutableSet;",
+            "import static java.util.stream.Collectors.toCollection;",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.ArrayList;",
+            "import java.util.HashMap;",
+            "import java.util.HashSet;",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collect(Collectors.toList());",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(2).collect(toList());",
+            "    Flux.just(3).collect(toImmutableList());",
+            "    Flux.just(4).collect(toCollection(ArrayList::new));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(\"foo\").collect(Collectors.toMap(String::getBytes, String::length));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(\"bar\").collect(toMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(toImmutableMap(String::getBytes, String::length));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> a));",
+            "    Flux.just(\"quux\").collect(toImmutableMap(String::getBytes, String::length, (a, b) -> a));",
+            "    Flux.just(\"quuz\").collect(toMap(String::getBytes, String::length, (a, b) -> a, HashMap::new));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Stream.of(1).collect(Collectors.toSet());",
+            "    // BUG: Diagnostic contains:",
+            "    Stream.of(2).collect(toSet());",
+            "    Stream.of(3).collect(toImmutableSet());",
+            "    Stream.of(4).collect(toCollection(HashSet::new));",
+            "",
+            "    Flux.just(\"foo\").collect(Collectors.joining());",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacementFirstSuggestedFix() {
+    refactoringTestHelper
+        .addInputLines(
+            "A.java",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(Collectors.toList());",
+            "    Flux.just(2).collect(toList());",
+            "",
+            "    Stream.of(\"foo\").collect(Collectors.toMap(String::getBytes, String::length));",
+            "    Stream.of(\"bar\").collect(toMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(Collectors.toMap(String::getBytes, String::length, (a, b) -> b));",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> b));",
+            "",
+            "    Stream.of(1).collect(Collectors.toSet());",
+            "    Stream.of(2).collect(toSet());",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "import static com.google.common.collect.ImmutableMap.toImmutableMap;",
+            "import static com.google.common.collect.ImmutableSet.toImmutableSet;",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toImmutableList());",
+            "    Flux.just(2).collect(toImmutableList());",
+            "",
+            "    Stream.of(\"foo\").collect(toImmutableMap(String::getBytes, String::length));",
+            "    Stream.of(\"bar\").collect(toImmutableMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(toImmutableMap(String::getBytes, String::length, (a, b) -> b));",
+            "    Flux.just(\"qux\").collect(toImmutableMap(String::getBytes, String::length, (a, b) -> b));",
+            "",
+            "    Stream.of(1).collect(toImmutableSet());",
+            "    Stream.of(2).collect(toImmutableSet());",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+
+  @Test
+  void replacementSecondSuggestedFix() {
+    refactoringTestHelper
+        .setFixChooser(SECOND)
+        .addInputLines(
+            "A.java",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(Collectors.toList());",
+            "    Flux.just(2).collect(toList());",
+            "",
+            "    Stream.of(\"foo\").collect(Collectors.toMap(String::getBytes, String::length));",
+            "    Stream.of(\"bar\").collect(toMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(Collectors.toMap(String::getBytes, String::length, (a, b) -> b));",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> b));",
+            "",
+            "    Stream.of(1).collect(Collectors.toSet());",
+            "    Stream.of(2).collect(toSet());",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static java.util.stream.Collectors.toCollection;",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.ArrayList;",
+            "import java.util.HashMap;",
+            "import java.util.HashSet;",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toCollection(ArrayList::new));",
+            "    Flux.just(2).collect(toCollection(ArrayList::new));",
+            "",
+            "    Stream.of(\"foo\")",
+            "        .collect(",
+            "            Collectors.toMap(",
+            "                String::getBytes,",
+            "                String::length,",
+            "                (a, b) -> {",
+            "                  throw new IllegalStateException();",
+            "                },",
+            "                HashMap::new));",
+            "    Stream.of(\"bar\")",
+            "        .collect(",
+            "            toMap(",
+            "                String::getBytes,",
+            "                String::length,",
+            "                (a, b) -> {",
+            "                  throw new IllegalStateException();",
+            "                },",
+            "                HashMap::new));",
+            "    Flux.just(\"baz\")",
+            "        .collect(Collectors.toMap(String::getBytes, String::length, (a, b) -> b, HashMap::new));",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> b, HashMap::new));",
+            "",
+            "    Stream.of(1).collect(toCollection(HashSet::new));",
+            "    Stream.of(2).collect(toCollection(HashSet::new));",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/EmptyMethodTest.java

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class EmptyMethodCheckTest {
+final class EmptyMethodTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(EmptyMethodCheck.class, getClass());
+      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(EmptyMethodCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());
 
   @Test
   void identification() {

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/ErrorProneTestHelperSourceFormatTest.java

@@ -0,0 +1,151 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class ErrorProneTestHelperSourceFormatTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(ErrorProneTestHelperSourceFormat.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(
+          ErrorProneTestHelperSourceFormat.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import tech.picnic.errorprone.bugpatterns.EmptyMethod;",
+            "",
+            "class A {",
+            "  private final CompilationTestHelper compilationTestHelper =",
+            "      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "  private final BugCheckerRefactoringTestHelper refactoringTestHelper =",
+            "      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "",
+            "  void m() {",
+            "    compilationTestHelper",
+            "        // BUG: Diagnostic contains: No source code provided",
+            "        .addSourceLines(\"A.java\")",
+            "        // BUG: Diagnostic contains: Source code is malformed:",
+            "        .addSourceLines(\"B.java\", \"class B {\")",
+            "        // Well-formed code, so not flagged.",
+            "        .addSourceLines(\"C.java\", \"class C {}\")",
+            "        // Malformed code, but not compile-time constant, so not flagged.",
+            "        .addSourceLines(\"D.java\", \"class D {\" + getClass())",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addSourceLines(\"E.java\", \"class E { }\")",
+            "        .doTest();",
+            "",
+            "    refactoringTestHelper",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addInputLines(\"in/A.java\", \"class A { }\")",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addOutputLines(\"out/A.java\", \"class A { }\")",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addInputLines(\"in/B.java\", \"import java.util.Map;\", \"\", \"class B {}\")",
+            "        // Unused import, but in an output file, so not flagged.",
+            "        .addOutputLines(\"out/B.java\", \"import java.util.Map;\", \"\", \"class B {}\")",
+            "        .doTest(TestMode.TEXT_MATCH);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    /*
+     * Verifies that import sorting and code formatting is performed unconditionally, while unused
+     * imports are removed unless part of a `BugCheckerRefactoringTestHelper` expected output file.
+     */
+    refactoringTestHelper
+        .addInputLines(
+            "in/A.java",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import tech.picnic.errorprone.bugpatterns.EmptyMethod;",
+            "",
+            "class A {",
+            "  private final CompilationTestHelper compilationTestHelper =",
+            "      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "  private final BugCheckerRefactoringTestHelper refactoringTestHelper =",
+            "      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "",
+            "  void m() {",
+            "    compilationTestHelper",
+            "        .addSourceLines(",
+            "            \"A.java\",",
+            "            \"import java.util.Map;\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A,A> { }\")",
+            "        .doTest();",
+            "",
+            "    refactoringTestHelper",
+            "        .addInputLines(",
+            "            \"in/A.java\",",
+            "            \"import java.util.Map;\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A,A> { }\")",
+            "        .addOutputLines(",
+            "            \"out/A.java\",",
+            "            \"import java.util.Map;\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A,A> { }\")",
+            "        .doTest(TestMode.TEXT_MATCH);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import tech.picnic.errorprone.bugpatterns.EmptyMethod;",
+            "",
+            "class A {",
+            "  private final CompilationTestHelper compilationTestHelper =",
+            "      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "  private final BugCheckerRefactoringTestHelper refactoringTestHelper =",
+            "      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "",
+            "  void m() {",
+            "    compilationTestHelper",
+            "        .addSourceLines(",
+            "            \"A.java\",",
+            "            \"import java.util.List;\",",
+            "            \"import java.util.Map;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A, A> {}\")",
+            "        .doTest();",
+            "",
+            "    refactoringTestHelper",
+            "        .addInputLines(",
+            "            \"in/A.java\",",
+            "            \"import java.util.List;\",",
+            "            \"import java.util.Map;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A, A> {}\")",
+            "        .addOutputLines(",
+            "            \"out/A.java\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"import java.util.Map;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A, A> {}\")",
+            "        .doTest(TestMode.TEXT_MATCH);",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/ExplicitEnumOrderingTest.java

@@ -3,23 +3,23 @@ package tech.picnic.errorprone.bugpatterns;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-final class ExplicitEnumOrderingCheckTest {
+final class ExplicitEnumOrderingTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(ExplicitEnumOrderingCheck.class, getClass());
+      CompilationTestHelper.newInstance(ExplicitEnumOrdering.class, getClass());
 
   @Test
-  void Identification() {
+  void identification() {
     compilationTestHelper
         .addSourceLines(
             "A.java",
-            "import static java.lang.annotation.RetentionPolicy.SOURCE;",
             "import static java.lang.annotation.RetentionPolicy.CLASS;",
             "import static java.lang.annotation.RetentionPolicy.RUNTIME;",
+            "import static java.lang.annotation.RetentionPolicy.SOURCE;",
             "import static java.time.chrono.IsoEra.BCE;",
             "import static java.time.chrono.IsoEra.CE;",
             "",
-            "import com.google.common.collect.Ordering;",
             "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.Ordering;",
             "import java.lang.annotation.RetentionPolicy;",
             "import java.time.chrono.IsoEra;",
             "",

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/FluxFlatMapUsageTest.java

@@ -0,0 +1,122 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.newInstance;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class FluxFlatMapUsageTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(FluxFlatMapUsage.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      newInstance(FluxFlatMapUsage.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import java.util.function.BiFunction;",
+            "import java.util.function.Function;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.core.publisher.Mono;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).flatMap(Flux::just);",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).<String>flatMap(i -> Flux.just(String.valueOf(i)));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).flatMapSequential(Flux::just);",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).<String>flatMapSequential(i -> Flux.just(String.valueOf(i)));",
+            "",
+            "    Mono.just(1).flatMap(Mono::just);",
+            "    Flux.just(1).concatMap(Flux::just);",
+            "",
+            "    Flux.just(1).flatMap(Flux::just, 1);",
+            "    Flux.just(1).flatMap(Flux::just, 1, 1);",
+            "    Flux.just(1).flatMap(Flux::just, throwable -> Flux.empty(), Flux::empty);",
+            "",
+            "    Flux.just(1).flatMapSequential(Flux::just, 1);",
+            "    Flux.just(1).flatMapSequential(Flux::just, 1, 1);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    this.<String, Flux<String>>sink(Flux::flatMap);",
+            "    // BUG: Diagnostic contains:",
+            "    this.<Integer, Flux<Integer>>sink(Flux::<Integer>flatMap);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    this.<String, Flux<String>>sink(Flux::flatMapSequential);",
+            "    // BUG: Diagnostic contains:",
+            "    this.<Integer, Flux<Integer>>sink(Flux::<Integer>flatMapSequential);",
+            "",
+            "    this.<String, Mono<String>>sink(Mono::flatMap);",
+            "  }",
+            "",
+            "  private <T, P> void sink(BiFunction<P, Function<T, P>, P> fun) {}",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacementFirstSuggestedFix() {
+    refactoringTestHelper
+        .setFixChooser(FixChoosers.FIRST)
+        .addInputLines(
+            "in/A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).flatMap(Flux::just);",
+            "    Flux.just(1).flatMapSequential(Flux::just);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).concatMap(Flux::just);",
+            "    Flux.just(1).concatMap(Flux::just);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacementSecondSuggestedFix() {
+    refactoringTestHelper
+        .setFixChooser(FixChoosers.SECOND)
+        .addInputLines(
+            "in/A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  private static final int MAX_CONCURRENCY = 8;",
+            "",
+            "  void m() {",
+            "    Flux.just(1).flatMap(Flux::just);",
+            "    Flux.just(1).flatMapSequential(Flux::just);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  private static final int MAX_CONCURRENCY = 8;",
+            "",
+            "  void m() {",
+            "    Flux.just(1).flatMap(Flux::just, MAX_CONCURRENCY);",
+            "    Flux.just(1).flatMapSequential(Flux::just, MAX_CONCURRENCY);",
+            "  }",
+            "}")
+        .doTest();
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/FormatStringConcatenationTest.java

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class FormatStringConcatenationCheckTest {
+final class FormatStringConcatenationTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(FormatStringConcatenationCheck.class, getClass());
+      CompilationTestHelper.newInstance(FormatStringConcatenation.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(FormatStringConcatenationCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(FormatStringConcatenation.class, getClass());
 
   @Test
   void identification() {
@@ -23,8 +23,8 @@ public final class FormatStringConcatenationCheckTest {
             "import static org.assertj.core.api.Assertions.assertThat;",
             "import static org.assertj.core.api.SoftAssertions.assertSoftly;",
             "",
-            "import java.util.Locale;",
             "import java.util.Formatter;",
+            "import java.util.Locale;",
             "import org.assertj.core.api.Assertions;",
             "import org.assertj.core.api.BDDAssertions;",
             "import org.assertj.core.api.Fail;",
@@ -269,9 +269,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.error(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.error((Marker) null,\"str \" + toString());",
+            "    LOG.error((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.error((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.error((Marker) null, \"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
             "    LOG.info(\"str \" + toString());",
@@ -279,9 +279,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.info(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.info((Marker) null,\"str \" + toString());",
+            "    LOG.info((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.info((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.info((Marker) null, \"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
             "    LOG.trace(\"str \" + toString());",
@@ -289,9 +289,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.trace(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.trace((Marker) null,\"str \" + toString());",
+            "    LOG.trace((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.trace((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.trace((Marker) null, \"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
             "    LOG.warn(\"str \" + toString());",
@@ -299,9 +299,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.warn(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.warn((Marker) null,\"str \" + toString());",
+            "    LOG.warn((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.warn((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.warn((Marker) null, \"{} \" + toString(), \"arg\");",
             "  }",
             "}")
         .doTest();
@@ -316,7 +316,6 @@ public final class FormatStringConcatenationCheckTest {
             "import static org.assertj.core.api.Assertions.assertThat;",
             "",
             "import java.util.Locale;",
-            "import java.util.Formatter;",
             "import org.slf4j.Logger;",
             "import org.slf4j.LoggerFactory;",
             "import org.slf4j.Marker;",
@@ -366,7 +365,6 @@ public final class FormatStringConcatenationCheckTest {
             "import static org.assertj.core.api.Assertions.assertThat;",
             "",
             "import java.util.Locale;",
-            "import java.util.Formatter;",
             "import org.slf4j.Logger;",
             "import org.slf4j.LoggerFactory;",
             "import org.slf4j.Marker;",
@@ -400,6 +398,7 @@ public final class FormatStringConcatenationCheckTest {
             "    String.format(\"{} \" + toString(), \"arg\");",
             "    String.format(Locale.ROOT, \"{} \" + toString(), \"arg\");",
             "  }",
+            "",
             "  void slf4j() {",
             "    LOG.debug(\"str {}\", toString());",
             "    LOG.debug((Marker) null, \"str {}\", toString());",