update submodules

See:
- https://github.com/raphw/byte-buddy/releases/tag/byte-buddy-1.14.9
- https://github.com/raphw/byte-buddy/compare/byte-buddy-1.14.8...byte-buddy-1.14.9

.github/ISSUE_TEMPLATE/bug_report.md

@@ -42,7 +42,7 @@ Please replace this sentence with log output, if applicable.
 <!-- Please complete the following information: -->
 
 - Operating system (e.g. MacOS Monterey).
-- Java version (i.e. `java --version`, e.g. `17.0.7`).
+- Java version (i.e. `java --version`, e.g. `17.0.8`).
 - Error Prone version (e.g. `2.18.0`).
 - Error Prone Support version (e.g. `0.9.0`).
 

.github/workflows/build.yaml

@@ -10,16 +10,16 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-22.04 ]
-        jdk: [ 11.0.19, 17.0.7, 20.0.1 ]
+        jdk: [ 11.0.20, 17.0.8, 20.0.2 ]
         distribution: [ temurin ]
         experimental: [ false ]
         include:
           - os: macos-12
-            jdk: 17.0.7
+            jdk: 17.0.8
             distribution: temurin
             experimental: false
           - os: windows-2022
-            jdk: 17.0.7
+            jdk: 17.0.8
             distribution: temurin
             experimental: false
     runs-on: ${{ matrix.os }}
@@ -31,11 +31,11 @@ jobs:
       # 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@v3.1.0
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
           java-version: ${{ matrix.jdk }}
           distribution: ${{ matrix.distribution }}

.github/workflows/codeql.yml

@@ -22,23 +22,23 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
-          java-version: 17.0.7
+          java-version: 17.0.8
           distribution: temurin
           cache: maven
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v2.2.11
+        uses: github/codeql-action/init@2cb752a87e96af96708ab57187ab6372ee1973ab # v2.22.0
         with:
           languages: ${{ matrix.language }}
       - name: Perform minimal build
         if: matrix.language == 'java'
         run: mvn -T1C clean install -DskipTests -Dverification.skip
       - name: Perform CodeQL analysis
-        uses: github/codeql-action/analyze@v2.2.11
+        uses: github/codeql-action/analyze@2cb752a87e96af96708ab57187ab6372ee1973ab # v2.22.0
         with:
           category: /language:${{ matrix.language }}

.github/workflows/deploy-website.yaml

@@ -12,15 +12,15 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           persist-credentials: false
-      - uses: ruby/setup-ruby@v1.126.0
+      - uses: ruby/setup-ruby@d37167af451eb51448db3354e1057b75c4b268f7 # v1.155.0
         with:
           working-directory: ./website
           bundler-cache: true
       - name: Configure Github Pages
-        uses: actions/configure-pages@v2.1.3
+        uses: actions/configure-pages@f156874f8191504dae5b037505266ed5dda6c382 # v3.0.6
       - name: Generate documentation
         run: ./generate-docs.sh
       - name: Build website with Jekyll
@@ -32,7 +32,7 @@ jobs:
         # "Refaster rules" terminology on our website and in the code.
         run: bundle exec htmlproofer --disable_external true --check-external-hash false ./_site
       - name: Upload website as artifact
-        uses: actions/upload-pages-artifact@v1.0.5
+        uses: actions/upload-pages-artifact@a753861a5debcf57bf8b404356158c8e1e33150c # v2.0.0
         with:
           path: ./website/_site
   deploy:
@@ -48,4 +48,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v1.2.3
+        uses: actions/deploy-pages@9dbe3824824f8a1377b8e298bafde1a50ede43e5 # v2.0.4

.github/workflows/integration-test.yml

@@ -0,0 +1,36 @@
+name: On-demand integration test
+on:
+  # run action every time a new comment is created
+  issue_comment:
+    types: [ created ]
+permissions:
+  contents: read
+jobs:
+  on_demand_integration_test:
+    name: On-demand integration test
+    # Only run the integration test if the created comment is on a pull request
+    # and contains the string `/integration-test`
+    if: | 
+      github.event.issue.pull_request &&
+      contains(github.event.comment.body, '/integration-test')
+    # XXX TODO: Device matrix? 
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out code
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1
+        with:
+          submodules: 'recursive'
+          persist-credentials: false
+      - name: Set up JDK
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
+        with:
+          # XXX TODO: java version matrix?
+          java-version: 17.0.8
+          distribution: temurin
+          cache: maven
+      - name: Display build environment details
+        run: mvn --version
+      - name: Install error-prone-support snapshot
+        run: mvn -T1C install -DskipTests -Dverification.skip
+      - name: Run integration test
+        run: echo "running integration test"

.github/workflows/openssf-scorecard.yml

@@ -21,16 +21,16 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           persist-credentials: false
       - name: Run OpenSSF Scorecard analysis
-        uses: ossf/scorecard-action@v2.1.3
+        uses: ossf/scorecard-action@483ef80eb98fb506c348f7d62e28055e49fe2398 # v2.3.0
         with:
           results_file: results.sarif
           results_format: sarif
           publish_results: ${{ github.ref == 'refs/heads/master' }}
       - name: Update GitHub's code scanning dashboard
-        uses: github/codeql-action/upload-sarif@v2.2.11
+        uses: github/codeql-action/upload-sarif@2cb752a87e96af96708ab57187ab6372ee1973ab # v2.22.0
         with:
           sarif_file: results.sarif

.github/workflows/pitest-analyze-pr.yml

@@ -12,14 +12,14 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           fetch-depth: 2
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
-          java-version: 17.0.7
+          java-version: 17.0.8
           distribution: temurin
           cache: maven
       - name: Run Pitest
@@ -32,7 +32,7 @@ jobs:
       - name: Aggregate Pitest reports
         run: mvn pitest-git:aggregate -DkilledEmoji=":tada:" -DmutantEmoji=":zombie:" -DtrailingText="Mutation testing report by [Pitest](https://pitest.org/). Review any surviving mutants by inspecting the line comments under [_Files changed_](${{ github.event.number }}/files)."
       - name: Upload Pitest reports as artifact
-        uses: actions/upload-artifact@v3.1.1
+        uses: actions/upload-artifact@a8a3f3ad30e3422c9c7b888a15615d19a852ae32 # v3.1.3
         with:
           name: pitest-reports
           path: ./target/pit-reports-ci

.github/workflows/pitest-update-pr.yml

@@ -20,17 +20,17 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
-          java-version: 17.0.7
+          java-version: 17.0.8
           distribution: temurin
           cache: maven
       - name: Download Pitest analysis artifact
-        uses: dawidd6/action-download-artifact@v2.24.2
+        uses: dawidd6/action-download-artifact@268677152d06ba59fcec7a7f0b5d961b6ccd7e1e # v2.28.0
         with:
           workflow: ${{ github.event.workflow_run.workflow_id }}
           name: pitest-reports

.github/workflows/sonarcloud.yml

@@ -16,14 +16,14 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@8ade135a41bc03ea155e62e844d188df1ea18608 # v4.1.0
         with:
           fetch-depth: 0
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@0ab4596768b603586c0de567f2430c30f5b0d2b0 # v3.13.0
         with:
-          java-version: 17.0.7
+          java-version: 17.0.8
           distribution: temurin
           cache: maven
       - name: Create missing `test` directory

.gitmodules

@@ -0,0 +1,15 @@
+[submodule "integration-tests/checkstyle"]
+	path = integration-tests/checkstyle
+	url = git@github.com:checkstyle/checkstyle.git
+[submodule "integration-tests/guava"]
+	path = integration-tests/guava
+	url = https://github.com/google/guava
+[submodule "integration-tests/metrics"]
+	path = integration-tests/metrics
+	url = https://github.com/dropwizard/metrics
+[submodule "integration-tests/druid"]
+	path = integration-tests/druid
+	url = https://github.com/apache/druid
+[submodule "integration-tests/calcite"]
+	path = integration-tests/calcite
+	url = https://github.com/apache/calcite

.renovaterc.json

@@ -1,5 +1,8 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "helpers:pinGitHubActionDigests"
+  ],
   "packageRules": [
     {
       "matchPackagePatterns": [
@@ -9,10 +12,11 @@
       "separateMinorPatch": true
     },
     {
-      "matchPackagePatterns": [
-        "^ruby\\/setup-ruby$"
+      "matchDepNames": [
+        "github/codeql-action",
+        "ruby/setup-ruby"
       ],
-      "schedule": "* * 1 * *"
+      "schedule": "every 4 weeks on Monday"
     }
   ],
   "reviewers": [

CONTRIBUTING.md

@@ -80,6 +80,6 @@ Some pointers:
 [error-prone-support-developing]: https://github.com/PicnicSupermarket/error-prone-support/tree/master#-developing-error-prone-support
 [error-prone-support-full-build]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/run-full-build.sh
 [error-prone-support-issues]: https://github.com/PicnicSupermarket/error-prone-support/issues
-[error-prone-support-mutation-tests]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/run-mutation-tests.sh
+[error-prone-support-mutation-tests]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/run-branch-mutation-tests.sh
 [error-prone-support-patch]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/apply-error-prone-suggestions.sh
 [error-prone-support-pulls]: https://github.com/PicnicSupermarket/error-prone-support/pulls

README.md

@@ -223,10 +223,13 @@ Other highly relevant commands:
   Before running this command, make sure to have installed the project (`mvn
   clean install`) and make sure that the current working directory does not
   contain unstaged or uncommited changes.
-- [`./run-mutation-tests.sh`][script-run-mutation-tests] runs mutation tests
-  using [Pitest][pitest]. The results can be reviewed by opening the respective
-  `target/pit-reports/index.html` files. For more information check the [PIT
-  Maven plugin][pitest-maven].
+- [`./run-branch-mutation-tests.sh`][script-run-branch-mutation-tests] uses
+  [Pitest][pitest] to run mutation tests against code that is modified relative
+  to the upstream default branch. The results can be reviewed by opening the
+  respective `target/pit-reports/index.html` files. One can use
+  [`./run-mutation-tests.sh`][script-run-mutation-tests] to run mutation tests
+  against _all_ code in the current working directory. For more information
+  check the [PIT Maven plugin][pitest-maven].
 
 When running the project's tests in IntelliJ IDEA, you might see the following
 error:
@@ -283,7 +286,7 @@ channel; please see our [security policy][security] for details.
 [openssf-best-practices-badge]: https://bestpractices.coreinfrastructure.org/projects/7199/badge
 [openssf-best-practices-checklist]: https://bestpractices.coreinfrastructure.org/projects/7199
 [openssf-scorecard-badge]: https://img.shields.io/ossf-scorecard/github.com/PicnicSupermarket/error-prone-support?label=openssf%20scorecard
-[openssf-scorecard-report]: https://api.securityscorecards.dev/projects/github.com/PicnicSupermarket/error-prone-support
+[openssf-scorecard-report]: https://securityscorecards.dev/viewer/?uri=github.com/PicnicSupermarket/error-prone-support
 [picnic-blog-ep-post]: https://blog.picnic.nl/picnic-loves-error-prone-producing-high-quality-and-consistent-java-code-b8a566be6886
 [picnic-blog]: https://blog.picnic.nl
 [pitest-badge]: https://img.shields.io/badge/-Mutation%20tested%20with%20PIT-blue.svg
@@ -296,6 +299,7 @@ channel; please see our [security policy][security] for details.
 [reproducible-builds-badge]: https://img.shields.io/badge/Reproducible_Builds-ok-success?labelColor=1e5b96
 [reproducible-builds-report]: https://github.com/jvm-repo-rebuild/reproducible-central/blob/master/content/tech/picnic/error-prone-support/error-prone-support/README.md
 [script-apply-error-prone-suggestions]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/apply-error-prone-suggestions.sh
+[script-run-branch-mutation-tests]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/run-branch-mutation-tests.sh
 [script-run-full-build]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/run-full-build.sh
 [script-run-mutation-tests]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/run-mutation-tests.sh
 [security]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/SECURITY.md

documentation-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.10.0</version>
+        <version>0.14.1-SNAPSHOT</version>
     </parent>
 
     <artifactId>documentation-support</artifactId>

error-prone-contrib/README.md

@@ -125,9 +125,6 @@ The following is a list of checks we'd like to see implemented:
   statement. Idem for other exception types.
 - A Guava-specific check that replaces simple anonymous `CacheLoader` subclass
   declarations with `CacheLoader.from(someLambda)`.
-- A Spring-specific check that enforces that methods with the `@Scheduled`
-  annotation are also annotated with New Relic's `@Trace` annotation. Such
-  methods should ideally not also represent Spring MVC endpoints.
 - A Spring-specific check that enforces that `@RequestMapping` annotations,
   when applied to a method, explicitly specify one or more target HTTP methods.
 - A Spring-specific check that looks for classes in which all `@RequestMapping`

error-prone-contrib/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.10.0</version>
+        <version>0.14.1-SNAPSHOT</version>
     </parent>
 
     <artifactId>error-prone-contrib</artifactId>
@@ -81,11 +81,6 @@
             <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>
@@ -126,6 +121,11 @@
             <artifactId>jakarta.servlet-api</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>javax.inject</groupId>
+            <artifactId>javax.inject</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>javax.xml.bind</groupId>
             <artifactId>jaxb-api</artifactId>
@@ -171,6 +171,11 @@
             <artifactId>mockito-core</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mongodb</groupId>
+            <artifactId>mongodb-driver-core</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.reactivestreams</groupId>
             <artifactId>reactive-streams</artifactId>

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

@@ -91,8 +91,8 @@ public final class CanonicalAnnotationSyntax extends BugChecker implements Annot
     ExpressionTree arg = args.get(0);
     if (state.getSourceForNode(arg) == null) {
       /*
-       * The annotation argument isn't doesn't have a source representation, e.g. because `value`
-       * isn't assigned to explicitly.
+       * The annotation argument doesn't have a source representation, e.g. because `value` isn't
+       * assigned explicitly.
        */
       return Optional.empty();
     }

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

@@ -59,6 +59,7 @@ import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 public final class FormatStringConcatenation extends BugChecker
     implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
+
   /**
    * AssertJ exposes varargs {@code fail} methods with a {@link Throwable}-accepting overload, the
    * latter of which should not be flagged.
@@ -68,6 +69,7 @@ public final class FormatStringConcatenation extends BugChecker
           .anyClass()
           .withAnyName()
           .withParameters(String.class.getName(), Throwable.class.getName());
+
   // XXX: Drop some of these methods if we use Refaster to replace some with others.
   private static final Matcher<ExpressionTree> ASSERTJ_FORMAT_METHOD =
       anyOf(

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

@@ -40,6 +40,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Stream;
+import javax.inject.Inject;
 import org.jspecify.annotations.Nullable;
 import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
 import tech.picnic.errorprone.bugpatterns.util.Flags;
@@ -75,6 +76,7 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
   private static final String FLAG_PREFIX = "LexicographicalAnnotationAttributeListing:";
   private static final String INCLUDED_ANNOTATIONS_FLAG = FLAG_PREFIX + "Includes";
   private static final String EXCLUDED_ANNOTATIONS_FLAG = FLAG_PREFIX + "Excludes";
+
   /**
    * The splitter applied to string-typed annotation arguments prior to lexicographical sorting. By
    * splitting on {@code =}, strings that represent e.g. inline Spring property declarations are
@@ -94,7 +96,8 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
    *
    * @param flags Any provided command line flags.
    */
-  public LexicographicalAnnotationAttributeListing(ErrorProneFlags flags) {
+  @Inject
+  LexicographicalAnnotationAttributeListing(ErrorProneFlags flags) {
     matcher = createAnnotationAttributeMatcher(flags);
   }
 
@@ -217,7 +220,10 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
   private static AnnotationAttributeMatcher createAnnotationAttributeMatcher(
       ErrorProneFlags flags) {
     return AnnotationAttributeMatcher.create(
-        flags.getList(INCLUDED_ANNOTATIONS_FLAG), excludedAnnotations(flags));
+        flags.get(INCLUDED_ANNOTATIONS_FLAG).isPresent()
+            ? Optional.of(flags.getListOrEmpty(INCLUDED_ANNOTATIONS_FLAG))
+            : Optional.empty(),
+        excludedAnnotations(flags));
   }
 
   private static ImmutableList<String> excludedAnnotations(ErrorProneFlags flags) {

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

@@ -46,6 +46,7 @@ import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 public final class LexicographicalAnnotationListing extends BugChecker
     implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
+
   /**
    * A comparator that minimally reorders {@link AnnotationType}s, such that declaration annotations
    * are placed before type annotations.

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

@@ -1,59 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
-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;
-import static com.google.errorprone.matchers.Matchers.isType;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-
-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.ClassTreeMatcher;
-import com.google.errorprone.matchers.Description;
-import com.google.errorprone.matchers.MultiMatcher;
-import com.google.errorprone.util.ASTHelpers;
-import com.sun.source.tree.AnnotationTree;
-import com.sun.source.tree.ClassTree;
-import com.sun.source.tree.MethodTree;
-import com.sun.source.tree.Tree;
-
-/** A {@link BugChecker} that flags likely missing Refaster annotations. */
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "The Refaster rule contains a method without any Refaster annotations",
-    link = BUG_PATTERNS_BASE_URL + "MissingRefasterAnnotation",
-    linkType = CUSTOM,
-    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(
-          AT_LEAST_ONE,
-          anyOf(
-              isType("com.google.errorprone.refaster.annotation.Placeholder"),
-              isType("com.google.errorprone.refaster.annotation.BeforeTemplate"),
-              isType("com.google.errorprone.refaster.annotation.AfterTemplate")));
-
-  /** Instantiates a new {@link MissingRefasterAnnotation} instance. */
-  public MissingRefasterAnnotation() {}
-
-  @Override
-  public Description matchClass(ClassTree tree, VisitorState state) {
-    long methodTypes =
-        tree.getMembers().stream()
-            .filter(member -> member.getKind() == Tree.Kind.METHOD)
-            .map(MethodTree.class::cast)
-            .filter(method -> !ASTHelpers.isGeneratedConstructor(method))
-            .map(method -> REFASTER_ANNOTATION.matches(method, state))
-            .distinct()
-            .count();
-
-    return methodTypes < 2 ? Description.NO_MATCH : buildDescription(tree).build();
-  }
-}

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

@@ -0,0 +1,47 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.PERFORMANCE;
+import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+
+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.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+
+/**
+ * A {@link BugChecker} that flags usages of MongoDB {@code $text} filter usages.
+ *
+ * @see <a href="https://www.mongodb.com/docs/manual/text-search/">MongoDB Text Search</a>
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary =
+        "Avoid MongoDB's `$text` filter operator, as it can trigger heavy queries and even cause the server to run out of memory",
+    link = BUG_PATTERNS_BASE_URL + "MongoDBTextFilterUsage",
+    linkType = CUSTOM,
+    severity = SUGGESTION,
+    tags = PERFORMANCE)
+public final class MongoDBTextFilterUsage extends BugChecker
+    implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> MONGO_FILTERS_TEXT_METHOD =
+      staticMethod().onClass("com.mongodb.client.model.Filters").named("text");
+
+  /** Instantiates a new {@link MongoDBTextFilterUsage} instance. */
+  public MongoDBTextFilterUsage() {}
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    return MONGO_FILTERS_TEXT_METHOD.matches(tree, state)
+        ? describeMatch(tree)
+        : Description.NO_MATCH;
+  }
+}

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

@@ -4,6 +4,7 @@ import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
 import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreMatchers.isSubTypeOf;
 import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.generic;
 import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.raw;
 import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.subOf;
@@ -14,14 +15,19 @@ import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
 import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.suppliers.Supplier;
 import com.google.errorprone.suppliers.Suppliers;
-import com.google.errorprone.util.ASTHelpers;
 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} that flags nesting of {@link Optional Optionals}. */
+// XXX: Extend this checker to also flag method return types and variable/field types.
+// XXX: Consider generalizing this checker and `NestedPublishers` to a single `NestedMonad` check,
+// which e.g. also flags nested `Stream`s. Alternatively, combine these and other checkers into an
+// even more generic `ConfusingType` checker.
 @AutoService(BugChecker.class)
 @BugPattern(
     summary =
@@ -33,19 +39,16 @@ import java.util.Optional;
 public final class NestedOptionals extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Supplier<Type> OPTIONAL = Suppliers.typeFromClass(Optional.class);
-  private static final Supplier<Type> OPTIONAL_OF_OPTIONAL =
-      VisitorState.memoize(generic(OPTIONAL, subOf(raw(OPTIONAL))));
+  private static final Matcher<Tree> IS_OPTIONAL_OF_OPTIONAL =
+      isSubTypeOf(VisitorState.memoize(generic(OPTIONAL, subOf(raw(OPTIONAL)))));
 
   /** Instantiates a new {@link NestedOptionals} instance. */
   public NestedOptionals() {}
 
   @Override
   public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    Type type = OPTIONAL_OF_OPTIONAL.get(state);
-    if (type == null || !state.getTypes().isSubtype(ASTHelpers.getType(tree), type)) {
-      return Description.NO_MATCH;
-    }
-
-    return describeMatch(tree);
+    return IS_OPTIONAL_OF_OPTIONAL.matches(tree, state)
+        ? describeMatch(tree)
+        : Description.NO_MATCH;
   }
 }

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

@@ -0,0 +1,63 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
+import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
+import static com.google.errorprone.matchers.Matchers.typePredicateMatcher;
+import static com.google.errorprone.predicates.TypePredicates.allOf;
+import static com.google.errorprone.predicates.TypePredicates.not;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypePredicates.hasTypeParameter;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypePredicates.isSubTypeOf;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.generic;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.raw;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.subOf;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.type;
+
+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.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.suppliers.Supplier;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.tools.javac.code.Type;
+
+/**
+ * A {@link BugChecker} that flags {@code Publisher<? extends Publisher>} instances, unless the
+ * nested {@link org.reactivestreams.Publisher} is a {@link reactor.core.publisher.GroupedFlux}.
+ */
+// XXX: See the `NestedOptionals` check for some ideas on how to generalize this kind of checker.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary =
+        "Avoid `Publisher`s that emit other `Publishers`s; "
+            + "the resultant code is hard to reason about",
+    link = BUG_PATTERNS_BASE_URL + "NestedPublishers",
+    linkType = CUSTOM,
+    severity = WARNING,
+    tags = FRAGILE_CODE)
+public final class NestedPublishers extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Supplier<Type> PUBLISHER = type("org.reactivestreams.Publisher");
+  private static final Matcher<ExpressionTree> IS_NON_GROUPED_PUBLISHER_OF_PUBLISHERS =
+      typePredicateMatcher(
+          allOf(
+              isSubTypeOf(generic(PUBLISHER, subOf(raw(PUBLISHER)))),
+              not(
+                  hasTypeParameter(
+                      0, isSubTypeOf(raw(type("reactor.core.publisher.GroupedFlux")))))));
+
+  /** Instantiates a new {@link NestedPublishers} instance. */
+  public NestedPublishers() {}
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    return IS_NON_GROUPED_PUBLISHER_OF_PUBLISHERS.matches(tree, state)
+        ? describeMatch(tree)
+        : Description.NO_MATCH;
+  }
+}

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

@@ -50,6 +50,7 @@ import java.util.Locale;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.stream.Stream;
+import javax.inject.Inject;
 import tech.picnic.errorprone.bugpatterns.util.Flags;
 import tech.picnic.errorprone.bugpatterns.util.MethodMatcherFactory;
 import tech.picnic.errorprone.bugpatterns.util.SourceCode;
@@ -155,7 +156,8 @@ public final class RedundantStringConversion extends BugChecker
    *
    * @param flags Any provided command line flags.
    */
-  public RedundantStringConversion(ErrorProneFlags flags) {
+  @Inject
+  RedundantStringConversion(ErrorProneFlags flags) {
     conversionMethodMatcher = createConversionMethodMatcher(flags);
   }
 

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

@@ -27,6 +27,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.suppliers.Suppliers;
 import com.sun.source.tree.Tree;
 import com.sun.source.tree.VariableTree;
+import javax.inject.Inject;
 import tech.picnic.errorprone.bugpatterns.util.Flags;
 
 /** A {@link BugChecker} that flags {@code @RequestParam} parameters with an unsupported type. */
@@ -55,7 +56,8 @@ public final class RequestParamType extends BugChecker implements VariableTreeMa
    *
    * @param flags Any provided command line flags.
    */
-  public RequestParamType(ErrorProneFlags flags) {
+  @Inject
+  RequestParamType(ErrorProneFlags flags) {
     hasUnsupportedRequestParamType = hasUnsupportedRequestParamType(flags);
   }
 

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

@@ -1,94 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
-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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-
-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;
-import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;
-
-/**
- * A {@link BugChecker} that 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",
-    link = BUG_PATTERNS_BASE_URL + "ScheduledTransactionTrace",
-    linkType = CUSTOM,
-    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));
-
-  /** Instantiates a new {@link ScheduledTransactionTrace} instance. */
-  public ScheduledTransactionTrace() {}
-
-  @Override
-  public Description matchMethod(MethodTree tree, VisitorState state) {
-    if (!ThirdPartyLibrary.NEW_RELIC_AGENT_API.isIntroductionAllowed(state)
-        || !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/StaticImport.java

@@ -155,6 +155,7 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
   @VisibleForTesting
   static final ImmutableSetMultimap<String, String> STATIC_IMPORT_EXEMPTED_MEMBERS =
       ImmutableSetMultimap.<String, String>builder()
+          .put("com.google.common.base.Predicates", "contains")
           .put("com.mongodb.client.model.Filters", "empty")
           .putAll(
               "java.util.Collections",

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

@@ -1,89 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
-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.instanceMethod;
-import static com.sun.tools.javac.parser.Tokens.TokenKind.RPAREN;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-
-import com.google.auto.service.AutoService;
-import com.google.common.collect.Streams;
-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.Fix;
-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.errorprone.util.ErrorProneTokens;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.MethodInvocationTree;
-import com.sun.tools.javac.util.Position;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
-
-/**
- * A {@link BugChecker} that flags calls to {@link String#toLowerCase()} and {@link
- * String#toUpperCase()}, as these methods implicitly rely on the environment's default locale.
- */
-// XXX: Also flag `String::toLowerCase` and `String::toUpperCase` method references. For these cases
-// the suggested fix should introduce a lambda expression with a parameter of which the name does
-// not coincide with the name of an existing variable name. Such functionality should likely be
-// introduced in a utility class.
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "Specify a `Locale` when calling `String#to{Lower,Upper}Case`",
-    link = BUG_PATTERNS_BASE_URL + "StringCaseLocaleUsage",
-    linkType = CUSTOM,
-    severity = WARNING,
-    tags = FRAGILE_CODE)
-public final class StringCaseLocaleUsage extends BugChecker implements MethodInvocationTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Matcher<ExpressionTree> DEFAULT_LOCALE_CASE_CONVERSION =
-      instanceMethod()
-          .onExactClass(String.class.getName())
-          .namedAnyOf("toLowerCase", "toUpperCase")
-          .withNoParameters();
-
-  /** Instantiates a new {@link StringCaseLocaleUsage} instance. */
-  public StringCaseLocaleUsage() {}
-
-  @Override
-  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    if (!DEFAULT_LOCALE_CASE_CONVERSION.matches(tree, state)) {
-      return Description.NO_MATCH;
-    }
-
-    int closingParenPosition = getClosingParenPosition(tree, state);
-    if (closingParenPosition == Position.NOPOS) {
-      return describeMatch(tree);
-    }
-
-    return buildDescription(tree)
-        .addFix(suggestLocale(closingParenPosition, "Locale.ROOT"))
-        .addFix(suggestLocale(closingParenPosition, "Locale.getDefault()"))
-        .build();
-  }
-
-  private static Fix suggestLocale(int insertPosition, String locale) {
-    return SuggestedFix.builder()
-        .addImport("java.util.Locale")
-        .replace(insertPosition, insertPosition, locale)
-        .build();
-  }
-
-  private static int getClosingParenPosition(MethodInvocationTree tree, VisitorState state) {
-    int startPosition = ASTHelpers.getStartPosition(tree);
-    if (startPosition == Position.NOPOS) {
-      return Position.NOPOS;
-    }
-
-    return Streams.findLast(
-            ErrorProneTokens.getTokens(SourceCode.treeToString(tree, state), state.context).stream()
-                .filter(t -> t.kind() == RPAREN))
-        .map(token -> startPosition + token.pos())
-        .orElse(Position.NOPOS);
-  }
-}

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

@@ -16,10 +16,7 @@ public final class Flags {
    *     provided, or if the flag's value is the empty string.
    */
   public static ImmutableList<String> getList(ErrorProneFlags errorProneFlags, String name) {
-    return errorProneFlags
-        .getList(name)
-        .map(ImmutableList::copyOf)
-        .filter(flags -> !flags.equals(ImmutableList.of("")))
-        .orElseGet(ImmutableList::of);
+    ImmutableList<String> list = errorProneFlags.getListOrEmpty(name);
+    return list.equals(ImmutableList.of("")) ? ImmutableList.of() : list;
   }
 }

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

@@ -17,6 +17,7 @@ public final class JavaKeywords {
    */
   private static final ImmutableSet<String> BOOLEAN_AND_NULL_LITERALS =
       ImmutableSet.of("true", "false", "null");
+
   /**
    * List of all reserved keywords in the Java language.
    *
@@ -76,6 +77,7 @@ public final class JavaKeywords {
           "void",
           "volatile",
           "while");
+
   /**
    * List of all contextual keywords in the Java language.
    *
@@ -100,6 +102,7 @@ public final class JavaKeywords {
           "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();

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

@@ -18,6 +18,7 @@ import java.util.regex.Pattern;
 public final class MethodMatcherFactory {
   private static final Splitter ARGUMENT_TYPE_SPLITTER =
       Splitter.on(',').trimResults().omitEmptyStrings();
+
   // XXX: Check whether we can use a parser for "standard" Java signatures here. Maybe
   // `sun.reflect.generics.parser.SignatureParser`?
   @SuppressWarnings("java:S5998" /* In practice there will be only modest recursion. */)

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

@@ -34,6 +34,7 @@ public final class MoreJUnitMatchers {
           anyOf(
               isType("org.junit.jupiter.api.Test"),
               hasMetaAnnotation("org.junit.jupiter.api.TestTemplate")));
+
   /** Matches JUnit Jupiter setup and teardown methods. */
   public static final MultiMatcher<MethodTree, AnnotationTree> SETUP_OR_TEARDOWN_METHOD =
       annotations(
@@ -43,6 +44,7 @@ public final class MoreJUnitMatchers {
               isType("org.junit.jupiter.api.AfterEach"),
               isType("org.junit.jupiter.api.BeforeAll"),
               isType("org.junit.jupiter.api.BeforeEach")));
+
   /**
    * Matches methods that have a {@link org.junit.jupiter.params.provider.MethodSource} annotation.
    */

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

@@ -1,11 +1,14 @@
 package tech.picnic.errorprone.bugpatterns.util;
 
+import static com.google.errorprone.matchers.Matchers.typePredicateMatcher;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypePredicates.hasAnnotation;
+
 import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.matchers.Matchers;
-import com.google.errorprone.predicates.TypePredicate;
-import com.google.errorprone.util.ASTHelpers;
+import com.google.errorprone.suppliers.Supplier;
 import com.sun.source.tree.AnnotationTree;
-import com.sun.tools.javac.code.Symbol;
+import com.sun.source.tree.Tree;
+import com.sun.tools.javac.code.Type;
 
 /**
  * A collection of general-purpose {@link Matcher}s.
@@ -25,15 +28,21 @@ public final class MoreMatchers {
    * @return A {@link Matcher} that matches trees with the specified meta-annotation.
    */
   public static <T extends AnnotationTree> Matcher<T> hasMetaAnnotation(String annotationType) {
-    TypePredicate typePredicate = hasAnnotation(annotationType);
-    return (tree, state) -> {
-      Symbol sym = ASTHelpers.getSymbol(tree);
-      return sym != null && typePredicate.apply(sym.type, state);
-    };
+    return typePredicateMatcher(hasAnnotation(annotationType));
   }
 
-  // XXX: Consider moving to a `MoreTypePredicates` utility class.
-  private static TypePredicate hasAnnotation(String annotationClassName) {
-    return (type, state) -> ASTHelpers.hasAnnotation(type.tsym, annotationClassName, state);
+  /**
+   * Returns a {@link Matcher} that determines whether the type of a given {@link Tree} is a subtype
+   * of the type returned by the specified {@link Supplier}.
+   *
+   * <p>This method differs from {@link Matchers#isSubtypeOf(Supplier)} in that it does not perform
+   * type erasure.
+   *
+   * @param <T> The type of tree to match against.
+   * @param type The {@link Supplier} that returns the type to match against.
+   * @return A {@link Matcher} that matches trees with the specified type.
+   */
+  public static <T extends Tree> Matcher<T> isSubTypeOf(Supplier<Type> type) {
+    return typePredicateMatcher(MoreTypePredicates.isSubTypeOf(type));
   }
 }

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

@@ -0,0 +1,63 @@
+package tech.picnic.errorprone.bugpatterns.util;
+
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.predicates.TypePredicate;
+import com.google.errorprone.predicates.TypePredicates;
+import com.google.errorprone.suppliers.Supplier;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.tools.javac.code.Type;
+import com.sun.tools.javac.util.List;
+
+/**
+ * A collection of general-purpose {@link TypePredicate}s.
+ *
+ * <p>These methods are additions to the ones found in {@link TypePredicates}.
+ */
+// XXX: The methods in this class are tested only indirectly. Consider adding a dedicated test
+// class, or make sure that each method is explicitly covered by a tested analog in `MoreMatchers`.
+public final class MoreTypePredicates {
+  private MoreTypePredicates() {}
+
+  /**
+   * Returns a {@link TypePredicate} that matches types that are annotated with the indicated
+   * annotation type.
+   *
+   * @param annotationType The fully-qualified name of the annotation type.
+   * @return A {@link TypePredicate} that matches appropriate types.
+   */
+  public static TypePredicate hasAnnotation(String annotationType) {
+    return (type, state) -> ASTHelpers.hasAnnotation(type.tsym, annotationType, state);
+  }
+
+  /**
+   * Returns a {@link TypePredicate} that matches subtypes of the type returned by the specified
+   * {@link Supplier}.
+   *
+   * @implNote This method does not use {@link ASTHelpers#isSubtype(Type, Type, VisitorState)}, as
+   *     that method performs type erasure.
+   * @param bound The {@link Supplier} that returns the type to match against.
+   * @return A {@link TypePredicate} that matches appropriate subtypes.
+   */
+  public static TypePredicate isSubTypeOf(Supplier<Type> bound) {
+    Supplier<Type> memoizedType = VisitorState.memoize(bound);
+    return (type, state) -> {
+      Type boundType = memoizedType.get(state);
+      return boundType != null && state.getTypes().isSubtype(type, boundType);
+    };
+  }
+
+  /**
+   * Returns a {@link TypePredicate} that matches generic types with a type parameter that matches
+   * the specified {@link TypePredicate} at the indicated index.
+   *
+   * @param index The index of the type parameter to match against.
+   * @param predicate The {@link TypePredicate} to match against the type parameter.
+   * @return A {@link TypePredicate} that matches appropriate generic types.
+   */
+  public static TypePredicate hasTypeParameter(int index, TypePredicate predicate) {
+    return (type, state) -> {
+      List<Type> typeArguments = type.getTypeArguments();
+      return typeArguments.size() > index && predicate.apply(typeArguments.get(index), state);
+    };
+  }
+}

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

@@ -4,7 +4,10 @@ import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.suppliers.Supplier;
 import com.sun.tools.javac.code.ClassFinder;
+import com.sun.tools.javac.code.Source;
 import com.sun.tools.javac.code.Symbol.CompletionFailure;
+import com.sun.tools.javac.code.Symbol.ModuleSymbol;
+import com.sun.tools.javac.code.Symtab;
 import com.sun.tools.javac.util.Name;
 
 /**
@@ -29,13 +32,6 @@ public enum ThirdPartyLibrary {
    * @see <a href="https://github.com/google/guava">Guava on GitHub</a>
    */
   GUAVA("com.google.common.collect.ImmutableList"),
-  /**
-   * New Relic's Java agent API.
-   *
-   * @see <a href="https://github.com/newrelic/newrelic-java-agent/tree/main/newrelic-api">New Relic
-   *     Java agent API on GitHub</a>
-   */
-  NEW_RELIC_AGENT_API("com.newrelic.api.agent.Agent"),
   /**
    * VMWare's Project Reactor.
    *
@@ -86,9 +82,15 @@ public enum ThirdPartyLibrary {
 
   private static boolean canLoadClass(String className, VisitorState state) {
     ClassFinder classFinder = ClassFinder.instance(state.context);
+    Symtab symtab = state.getSymtab();
+    // XXX: Drop support for targeting Java 8 once the oldest supported JDK drops such support.
+    ModuleSymbol module =
+        Source.instance(state.context).compareTo(Source.JDK9) < 0
+            ? symtab.noModule
+            : symtab.unnamedModule;
     Name binaryName = state.binaryNameFromClassname(className);
     try {
-      classFinder.loadClass(state.getSymtab().unnamedModule, binaryName);
+      classFinder.loadClass(module, binaryName);
       return true;
     } catch (
         @SuppressWarnings("java:S1166" /* Not exceptional. */)

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/AssortedRules.java

@@ -103,8 +103,7 @@ final class AssortedRules {
     }
 
     @AfterTemplate
-    @Nullable
-    T after(Iterator<T> iterator, T defaultValue) {
+    @Nullable T after(Iterator<T> iterator, T defaultValue) {
       return Iterators.getNext(iterator, defaultValue);
     }
   }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BugCheckerRules.java

@@ -3,6 +3,7 @@ package tech.picnic.errorprone.refasterrules;
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChooser;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -25,6 +26,7 @@ final class BugCheckerRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     BugCheckerRefactoringTestHelper after(BugCheckerRefactoringTestHelper helper) {
       return helper;
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ClassRules.java

@@ -0,0 +1,65 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.errorprone.refaster.Refaster;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.util.function.Predicate;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to expressions dealing with classes. */
+@OnlineDocumentation
+final class ClassRules {
+  private ClassRules() {}
+
+  /** Prefer {@link Class#isInstance(Object)} over more contrived alternatives. */
+  static final class ClassIsInstance<T, S> {
+    @BeforeTemplate
+    boolean before(Class<T> clazz, S object) {
+      return clazz.isAssignableFrom(object.getClass());
+    }
+
+    @AfterTemplate
+    boolean after(Class<T> clazz, S object) {
+      return clazz.isInstance(object);
+    }
+  }
+
+  /** Prefer using the {@code instanceof} keyword over less idiomatic alternatives. */
+  static final class Instanceof<T, S> {
+    @BeforeTemplate
+    boolean before(S object) {
+      return Refaster.<T>clazz().isInstance(object);
+    }
+
+    @AfterTemplate
+    boolean after(S object) {
+      return Refaster.<T>isInstance(object);
+    }
+  }
+
+  /** Prefer {@link Class#isInstance(Object)} method references over more verbose alternatives. */
+  static final class ClassLiteralIsInstancePredicate<T, S> {
+    @BeforeTemplate
+    Predicate<S> before() {
+      return o -> Refaster.<T>isInstance(o);
+    }
+
+    @AfterTemplate
+    Predicate<S> after() {
+      return Refaster.<T>clazz()::isInstance;
+    }
+  }
+
+  /** Prefer {@link Class#isInstance(Object)} method references over more verbose alternatives. */
+  static final class ClassReferenceIsInstancePredicate<T, S> {
+    @BeforeTemplate
+    Predicate<S> before(Class<T> clazz) {
+      return o -> clazz.isInstance(o);
+    }
+
+    @AfterTemplate
+    Predicate<S> after(Class<T> clazz) {
+      return clazz::isInstance;
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/CollectionRules.java

@@ -74,6 +74,19 @@ final class CollectionRules {
     }
   }
 
+  /** Prefer {@link Collection#contains(Object)} over more contrived alternatives. */
+  static final class CollectionContains<T, S> {
+    @BeforeTemplate
+    boolean before(Collection<T> collection, S value) {
+      return collection.stream().anyMatch(value::equals);
+    }
+
+    @AfterTemplate
+    boolean after(Collection<T> collection, S value) {
+      return collection.contains(value);
+    }
+  }
+
   /**
    * Don't call {@link Iterables#addAll(Collection, Iterable)} when the elements to be added are
    * already part of a {@link Collection}.
@@ -164,6 +177,8 @@ final class CollectionRules {
   }
 
   /** Prefer {@link ArrayList#ArrayList(Collection)} over the Guava alternative. */
+  @SuppressWarnings(
+      "NonApiType" /* Matching against `List` would unnecessarily constrain the rule. */)
   static final class NewArrayListFromCollection<T> {
     @BeforeTemplate
     ArrayList<T> before(Collection<T> collection) {

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ComparatorRules.java

@@ -12,6 +12,7 @@ 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.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -78,6 +79,7 @@ final class ComparatorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<T> after(Comparator<T> cmp) {
       return cmp;
@@ -219,7 +221,6 @@ final class ComparatorRules {
    */
   static final class MinOfVarargs<T> {
     @BeforeTemplate
-    @SuppressWarnings("StreamOfArray" /* In practice individual values are provided. */)
     T before(@Repeated T value, Comparator<T> cmp) {
       return Stream.of(Refaster.asVarargs(value)).min(cmp).orElseThrow();
     }
@@ -287,7 +288,6 @@ final class ComparatorRules {
    */
   static final class MaxOfVarargs<T> {
     @BeforeTemplate
-    @SuppressWarnings("StreamOfArray" /* In practice individual values are provided. */)
     T before(@Repeated T value, Comparator<T> cmp) {
       return Stream.of(Refaster.asVarargs(value)).max(cmp).orElseThrow();
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/DoubleStreamRules.java

@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.refasterrules;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -27,6 +28,7 @@ final class DoubleStreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     DoubleStream after(DoubleStream stream) {
       return stream;
     }
@@ -275,4 +277,16 @@ final class DoubleStreamRules {
       return stream.allMatch(e -> test(e));
     }
   }
+
+  static final class DoubleStreamTakeWhile {
+    @BeforeTemplate
+    DoubleStream before(DoubleStream stream, DoublePredicate predicate) {
+      return stream.takeWhile(predicate).filter(predicate);
+    }
+
+    @AfterTemplate
+    DoubleStream after(DoubleStream stream, DoublePredicate predicate) {
+      return stream.takeWhile(predicate);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/EqualityRules.java

@@ -1,10 +1,16 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static java.util.function.Predicate.not;
+
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.AlsoNegation;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.MayOptionallyUse;
+import com.google.errorprone.refaster.annotation.Placeholder;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.function.Predicate;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
@@ -63,6 +69,7 @@ final class EqualityRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     boolean after(boolean b) {
       return b;
     }
@@ -129,4 +136,62 @@ final class EqualityRules {
       return a == b;
     }
   }
+
+  /**
+   * Don't pass a lambda expression to {@link Predicate#not(Predicate)}; instead push the negation
+   * into the lambda expression.
+   */
+  abstract static class PredicateLambda<T> {
+    @Placeholder(allowsIdentity = true)
+    abstract boolean predicate(@MayOptionallyUse T value);
+
+    @BeforeTemplate
+    Predicate<T> before() {
+      return not(v -> predicate(v));
+    }
+
+    @AfterTemplate
+    Predicate<T> after() {
+      return v -> !predicate(v);
+    }
+  }
+
+  /** Avoid contrived ways of handling {@code null} values during equality testing. */
+  static final class EqualsLhsNullable<T, S> {
+    @BeforeTemplate
+    boolean before(T value1, S value2) {
+      return Optional.ofNullable(value1).equals(Optional.of(value2));
+    }
+
+    @AfterTemplate
+    boolean after(T value1, S value2) {
+      return value2.equals(value1);
+    }
+  }
+
+  /** Avoid contrived ways of handling {@code null} values during equality testing. */
+  static final class EqualsRhsNullable<T, S> {
+    @BeforeTemplate
+    boolean before(T value1, S value2) {
+      return Optional.of(value1).equals(Optional.ofNullable(value2));
+    }
+
+    @AfterTemplate
+    boolean after(T value1, S value2) {
+      return value1.equals(value2);
+    }
+  }
+
+  /** Avoid contrived ways of handling {@code null} values during equality testing. */
+  static final class EqualsLhsAndRhsNullable<T, S> {
+    @BeforeTemplate
+    boolean before(T value1, S value2) {
+      return Optional.ofNullable(value1).equals(Optional.ofNullable(value2));
+    }
+
+    @AfterTemplate
+    boolean after(T value1, S value2) {
+      return Objects.equals(value1, value2);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/FileRules.java

@@ -0,0 +1,43 @@
+package tech.picnic.errorprone.refasterrules;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to expressions dealing with files. */
+@OnlineDocumentation
+final class FileRules {
+  private FileRules() {}
+
+  /** Prefer {@link Files#readString(Path, Charset)} over more contrived alternatives. */
+  static final class FilesReadStringWithCharset {
+    @BeforeTemplate
+    String before(Path path, Charset charset) throws IOException {
+      return new String(Files.readAllBytes(path), charset);
+    }
+
+    @AfterTemplate
+    String after(Path path, Charset charset) throws IOException {
+      return Files.readString(path, charset);
+    }
+  }
+
+  /** Prefer {@link Files#readString(Path)} over more verbose alternatives. */
+  static final class FilesReadString {
+    @BeforeTemplate
+    String before(Path path) throws IOException {
+      return Files.readString(path, UTF_8);
+    }
+
+    @AfterTemplate
+    String after(Path path) throws IOException {
+      return Files.readString(path);
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/IntStreamRules.java

@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.refasterrules;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -40,6 +41,7 @@ final class IntStreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     IntStream after(IntStream stream) {
       return stream;
     }
@@ -288,4 +290,16 @@ final class IntStreamRules {
       return stream.allMatch(e -> test(e));
     }
   }
+
+  static final class IntStreamTakeWhile {
+    @BeforeTemplate
+    IntStream before(IntStream stream, IntPredicate predicate) {
+      return stream.takeWhile(predicate).filter(predicate);
+    }
+
+    @AfterTemplate
+    IntStream after(IntStream stream, IntPredicate predicate) {
+      return stream.takeWhile(predicate);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/LongStreamRules.java

@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.refasterrules;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -40,6 +41,7 @@ final class LongStreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     LongStream after(LongStream stream) {
       return stream;
     }
@@ -288,4 +290,16 @@ final class LongStreamRules {
       return stream.allMatch(e -> test(e));
     }
   }
+
+  static final class LongStreamTakeWhile {
+    @BeforeTemplate
+    LongStream before(LongStream stream, LongPredicate predicate) {
+      return stream.takeWhile(predicate).filter(predicate);
+    }
+
+    @AfterTemplate
+    LongStream after(LongStream stream, LongPredicate predicate) {
+      return stream.takeWhile(predicate);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/MapRules.java

@@ -33,14 +33,12 @@ final class MapRules {
 
   static final class MapGetOrNull<K, V, T> {
     @BeforeTemplate
-    @Nullable
-    V before(Map<K, V> map, T key) {
+    @Nullable V before(Map<K, V> map, T key) {
       return map.getOrDefault(key, null);
     }
 
     @AfterTemplate
-    @Nullable
-    V after(Map<K, V> map, T key) {
+    @Nullable V after(Map<K, V> map, T key) {
       return map.get(key);
     }
   }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/MockitoRules.java

@@ -5,10 +5,12 @@ import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
+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 org.mockito.Mockito;
+import org.mockito.invocation.InvocationOnMock;
 import org.mockito.verification.VerificationMode;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
@@ -50,4 +52,30 @@ final class MockitoRules {
       return verify(mock);
     }
   }
+
+  static final class InvocationOnMockGetArguments {
+    @BeforeTemplate
+    Object before(InvocationOnMock invocation, int i) {
+      return invocation.getArguments()[i];
+    }
+
+    @AfterTemplate
+    Object after(InvocationOnMock invocation, int i) {
+      return invocation.getArgument(i);
+    }
+  }
+
+  static final class InvocationOnMockGetArgumentsWithTypeParameter<T> {
+    @BeforeTemplate
+    @SuppressWarnings("unchecked")
+    T before(InvocationOnMock invocation, int i) {
+      return Refaster.anyOf(
+          invocation.getArgument(i, Refaster.<T>clazz()), (T) invocation.getArgument(i));
+    }
+
+    @AfterTemplate
+    T after(InvocationOnMock invocation, int i) {
+      return invocation.<T>getArgument(i);
+    }
+  }
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/MultimapRules.java

@@ -50,8 +50,7 @@ final class MultimapRules {
    */
   static final class MultimapGet<K, V> {
     @BeforeTemplate
-    @Nullable
-    Collection<V> before(Multimap<K, V> multimap, K key) {
+    @Nullable Collection<V> before(Multimap<K, V> multimap, K key) {
       return Refaster.anyOf(multimap.asMap(), Multimaps.asMap(multimap)).get(key);
     }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/OptionalRules.java

@@ -3,10 +3,12 @@ package tech.picnic.errorprone.refasterrules;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 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.NotMatches;
 import com.google.errorprone.refaster.annotation.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Comparator;
@@ -18,6 +20,7 @@ import java.util.function.Supplier;
 import java.util.stream.Stream;
 import org.jspecify.annotations.Nullable;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.matchers.IsLikelyTrivialComputation;
 
 /** Refaster rules related to expressions dealing with {@link Optional}s. */
 @OnlineDocumentation
@@ -97,6 +100,20 @@ final class OptionalRules {
     }
   }
 
+  /** Prefer {@link Optional#equals(Object)} over more contrived alternatives. */
+  static final class OptionalEqualsOptional<T, S> {
+    @BeforeTemplate
+    boolean before(Optional<T> optional, S value) {
+      return Refaster.anyOf(
+          optional.filter(value::equals).isPresent(), optional.stream().anyMatch(value::equals));
+    }
+
+    @AfterTemplate
+    boolean after(Optional<T> optional, S value) {
+      return optional.equals(Optional.of(value));
+    }
+  }
+
   /**
    * Don't use the ternary operator to extract the first element of a possibly-empty {@link
    * Iterator} as an {@link Optional}.
@@ -117,7 +134,7 @@ final class OptionalRules {
   /** 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 `Refaster` checker should test `compilesWithFix`?
+  // Review whether a `@Matcher` can be used to avoid this.
   abstract static class TernaryOperatorOptionalPositiveFiltering<T> {
     @Placeholder
     abstract boolean test(T value);
@@ -137,7 +154,7 @@ final class OptionalRules {
   /** 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 `Refaster` checker should test `compilesWithFix`?
+  // Review whether a `@Matcher` can be used to avoid this.
   abstract static class TernaryOperatorOptionalNegativeFiltering<T> {
     @Placeholder
     abstract boolean test(T value);
@@ -160,6 +177,7 @@ final class OptionalRules {
    */
   static final class MapOptionalToBoolean<T> {
     @BeforeTemplate
+    @SuppressWarnings("OptionalOrElseGet" /* Rule is confused by `Refaster#anyOf` usage. */)
     boolean before(Optional<T> optional, Function<? super T, Boolean> predicate) {
       return optional.map(predicate).orElse(Refaster.anyOf(false, Boolean.FALSE));
     }
@@ -223,6 +241,28 @@ final class OptionalRules {
     }
   }
 
+  /**
+   * Prefer {@link Optional#orElseGet(Supplier)} over {@link Optional#orElse(Object)} if the
+   * fallback value is not the result of a trivial computation.
+   */
+  // XXX: This rule may introduce a compilation error: the `value` expression may reference a
+  // non-effectively final variable, which is not allowed in the replacement lambda expression.
+  // Review whether a `@Matcher` can be used to avoid this.
+  // XXX: Once `MethodReferenceUsage` is "production ready", replace
+  // `@NotMatches(IsLikelyTrivialComputation.class)` with `@Matches(RequiresComputation.class)` (and
+  // reimplement the matcher accordingly).
+  static final class OptionalOrElseGet<T> {
+    @BeforeTemplate
+    T before(Optional<T> optional, @NotMatches(IsLikelyTrivialComputation.class) T value) {
+      return optional.orElse(value);
+    }
+
+    @AfterTemplate
+    T after(Optional<T> optional, T value) {
+      return optional.orElseGet(() -> value);
+    }
+  }
+
   /**
    * Flatten a stream of {@link Optional}s using {@link Optional#stream()}, rather than using one of
    * the more verbose alternatives.
@@ -324,10 +364,14 @@ final class OptionalRules {
     Optional<T> before(Optional<T> optional1, Optional<T> optional2) {
       // XXX: Note that rewriting the first and third variant will change the code's behavior if
       // `optional2` has side-effects.
+      // XXX: Note that rewriting the first, third and fourth variant will introduce a compilation
+      // error if `optional2` is not effectively final. Review whether a `@Matcher` can be used to
+      // avoid this.
       return Refaster.anyOf(
           optional1.map(Optional::of).orElse(optional2),
           optional1.map(Optional::of).orElseGet(() -> optional2),
-          Stream.of(optional1, optional2).flatMap(Optional::stream).findFirst());
+          Stream.of(optional1, optional2).flatMap(Optional::stream).findFirst(),
+          optional1.isPresent() ? optional1 : optional2);
     }
 
     @AfterTemplate
@@ -351,6 +395,7 @@ final class OptionalRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Optional<T> after(Optional<T> optional) {
       return optional;
     }
@@ -392,12 +437,22 @@ final class OptionalRules {
     }
   }
 
-  // XXX: Add a rule for:
-  // `optional.flatMap(x -> pred(x) ? Optional.empty() : Optional.of(x))` and variants.
-  // (Maybe canonicalize the inner expression. Maybe we rewrite already.)
+  /** Prefer {@link Optional#stream()} over more contrived alternatives. */
+  static final class OptionalStream<T> {
+    @BeforeTemplate
+    Stream<T> before(Optional<T> optional) {
+      return Refaster.anyOf(
+          optional.map(Stream::of).orElse(Stream.empty()),
+          optional.map(Stream::of).orElseGet(Stream::empty));
+    }
+
+    @AfterTemplate
+    Stream<T> after(Optional<T> optional) {
+      return optional.stream();
+    }
+  }
 
   // XXX: Add a rule for:
-  // `optional.map(Stream::of).orElse(Stream.empty())`
-  // `optional.map(Stream::of).orElseGet(Stream::empty)`
-  // -> `optional.stream()`
+  // `optional.flatMap(x -> pred(x) ? Optional.empty() : Optional.of(x))` and variants.
+  // (Maybe canonicalize the inner expression. Maybe we rewrite it already.)
 }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/PatternRules.java

@@ -0,0 +1,46 @@
+package tech.picnic.errorprone.refasterrules;
+
+import static com.google.common.base.Predicates.containsPattern;
+
+import com.google.common.base.Predicates;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to code dealing with regular expressions. */
+@OnlineDocumentation
+final class PatternRules {
+  private PatternRules() {}
+
+  /** Prefer {@link Pattern#asPredicate()} over non-JDK alternatives. */
+  // XXX: This rule could also replace `s -> pattern.matcher(s).find()`, though the lambda
+  // expression may match functional interfaces other than `Predicate`. If we do add such a rule, we
+  // should also add a rule that replaces `s -> pattern.matcher(s).matches()` with
+  // `pattern.asMatchPredicate()`.
+  static final class PatternAsPredicate {
+    @BeforeTemplate
+    Predicate<CharSequence> before(Pattern pattern) {
+      return Predicates.contains(pattern);
+    }
+
+    @AfterTemplate
+    Predicate<String> after(Pattern pattern) {
+      return pattern.asPredicate();
+    }
+  }
+
+  /** Prefer {@link Pattern#asPredicate()} over non-JDK alternatives. */
+  static final class PatternCompileAsPredicate {
+    @BeforeTemplate
+    Predicate<CharSequence> before(String pattern) {
+      return containsPattern(pattern);
+    }
+
+    @AfterTemplate
+    Predicate<String> after(String pattern) {
+      return Pattern.compile(pattern).asPredicate();
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java

@@ -14,6 +14,7 @@ import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -246,11 +247,43 @@ final class ReactorRules {
     }
   }
 
+  /** Prefer {@link Flux#zipWithIterable(Iterable)} over more contrived alternatives. */
+  static final class FluxZipWithIterable<T, S> {
+    @BeforeTemplate
+    Flux<Tuple2<T, S>> before(Flux<T> flux, Iterable<S> iterable) {
+      return Flux.zip(flux, Flux.fromIterable(iterable));
+    }
+
+    @AfterTemplate
+    Flux<Tuple2<T, S>> after(Flux<T> flux, Iterable<S> iterable) {
+      return flux.zipWithIterable(iterable);
+    }
+  }
+
+  /** Prefer {@link Flux#zipWithIterable(Iterable, BiFunction)} over more contrived alternatives. */
+  static final class FluxZipWithIterableBiFunction<T, S, R> {
+    @BeforeTemplate
+    Flux<R> before(
+        Flux<T> flux,
+        Iterable<S> iterable,
+        BiFunction<? super T, ? super S, ? extends R> function) {
+      return flux.zipWith(Flux.fromIterable(iterable), function);
+    }
+
+    @AfterTemplate
+    Flux<R> after(
+        Flux<T> flux,
+        Iterable<S> iterable,
+        BiFunction<? super T, ? super S, ? extends R> function) {
+      return flux.zipWithIterable(iterable, function);
+    }
+  }
+
   /**
    * Prefer {@link Flux#zipWithIterable(Iterable)} with a chained combinator over {@link
    * Flux#zipWithIterable(Iterable, BiFunction)}, as the former generally yields more readable code.
    */
-  static final class FluxZipWithIterable<T, S, R> {
+  static final class FluxZipWithIterableMapFunction<T, S, R> {
     @BeforeTemplate
     Flux<R> before(Flux<T> flux, Iterable<S> iterable, BiFunction<T, S, R> combinator) {
       return flux.zipWithIterable(iterable, combinator);
@@ -327,7 +360,10 @@ final class ReactorRules {
   static final class MonoThenReturn<T, S> {
     @BeforeTemplate
     Mono<S> before(Mono<T> mono, S object) {
-      return mono.then(Mono.just(object));
+      return Refaster.anyOf(
+          mono.ignoreElement().thenReturn(object),
+          mono.then().thenReturn(object),
+          mono.then(Mono.just(object)));
     }
 
     @AfterTemplate
@@ -390,6 +426,74 @@ final class ReactorRules {
     }
   }
 
+  /** Prefer {@link Flux#empty()} over more contrived alternatives. */
+  // XXX: In combination with the `IsEmpty` matcher introduced by
+  // https://github.com/PicnicSupermarket/error-prone-support/pull/744, the non-varargs overloads of
+  // most methods referenced here can be rewritten as well. Additionally, some invocations of
+  // methods such as `Flux#fromIterable`, `Flux#fromArray` and `Flux#justOrEmpty` can also be
+  // rewritten.
+  static final class FluxEmpty<T, S extends Comparable<? super S>> {
+    @BeforeTemplate
+    Flux<T> before(
+        int prefetch,
+        Function<? super Object[], ? extends T> combinator,
+        Comparator<? super T> comparator) {
+      return Refaster.anyOf(
+          Flux.concat(),
+          Flux.concatDelayError(),
+          Flux.firstWithSignal(),
+          Flux.just(),
+          Flux.merge(),
+          Flux.merge(prefetch),
+          Flux.mergeComparing(comparator),
+          Flux.mergeComparing(prefetch, comparator),
+          Flux.mergeComparingDelayError(prefetch, comparator),
+          Flux.mergeDelayError(prefetch),
+          Flux.mergePriority(comparator),
+          Flux.mergePriority(prefetch, comparator),
+          Flux.mergePriorityDelayError(prefetch, comparator),
+          Flux.mergeSequential(),
+          Flux.mergeSequential(prefetch),
+          Flux.mergeSequentialDelayError(prefetch),
+          Flux.zip(combinator),
+          Flux.zip(combinator, prefetch));
+    }
+
+    @BeforeTemplate
+    Flux<T> before(int prefetch, Function<Object[], T> combinator) {
+      return Refaster.anyOf(
+          Flux.combineLatest(combinator), Flux.combineLatest(combinator, prefetch));
+    }
+
+    @BeforeTemplate
+    Flux<S> before() {
+      return Refaster.anyOf(Flux.mergeComparing(), Flux.mergePriority());
+    }
+
+    @BeforeTemplate
+    Flux<Integer> before(int start) {
+      return Flux.range(start, 0);
+    }
+
+    @AfterTemplate
+    Flux<T> after() {
+      return Flux.empty();
+    }
+  }
+
+  /** Prefer {@link Flux#just(Object)} over more contrived alternatives. */
+  static final class FluxJust {
+    @BeforeTemplate
+    Flux<Integer> before(int start) {
+      return Flux.range(start, 1);
+    }
+
+    @AfterTemplate
+    Flux<Integer> after(int start) {
+      return Flux.just(start);
+    }
+  }
+
   /** Don't unnecessarily transform a {@link Mono} to an equivalent instance. */
   static final class MonoIdentity<T> {
     @BeforeTemplate
@@ -400,7 +504,7 @@ final class ReactorRules {
 
     @BeforeTemplate
     Mono<@Nullable Void> before2(Mono<@Nullable Void> mono) {
-      return mono.then();
+      return Refaster.anyOf(mono.ignoreElement(), mono.then());
     }
 
     // XXX: Replace this rule with an extension of the `IdentityConversion` rule, supporting
@@ -411,11 +515,25 @@ final class ReactorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Mono<T> after(Mono<T> mono) {
       return mono;
     }
   }
 
+  /** Don't unnecessarily transform a {@link Mono} to a {@link Flux} to expect exactly one item. */
+  static final class MonoSingle<T> {
+    @BeforeTemplate
+    Mono<T> before(Mono<T> mono) {
+      return mono.flux().single();
+    }
+
+    @AfterTemplate
+    Mono<T> after(Mono<T> mono) {
+      return mono.single();
+    }
+  }
+
   /** Don't unnecessarily pass an empty publisher to {@link Flux#switchIfEmpty(Publisher)}. */
   static final class FluxSwitchIfEmptyOfEmptyPublisher<T> {
     @BeforeTemplate
@@ -424,6 +542,7 @@ final class ReactorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Flux<T> after(Flux<T> flux) {
       return flux;
     }
@@ -432,6 +551,7 @@ final class ReactorRules {
   /** Prefer {@link Flux#concatMap(Function)} over more contrived alternatives. */
   static final class FluxConcatMap<T, S> {
     @BeforeTemplate
+    @SuppressWarnings("NestedPublishers")
     Flux<S> before(Flux<T> flux, Function<? super T, ? extends Publisher<? extends S>> function) {
       return Refaster.anyOf(
           flux.flatMap(function, 1),
@@ -448,6 +568,7 @@ final class ReactorRules {
   /** Prefer {@link Flux#concatMap(Function, int)} over more contrived alternatives. */
   static final class FluxConcatMapWithPrefetch<T, S> {
     @BeforeTemplate
+    @SuppressWarnings("NestedPublishers")
     Flux<S> before(
         Flux<T> flux,
         Function<? super T, ? extends Publisher<? extends S>> function,
@@ -467,14 +588,46 @@ final class ReactorRules {
     }
   }
 
+  /** Avoid contrived alternatives to {@link Mono#flatMapIterable(Function)}. */
+  static final class MonoFlatMapIterable<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Mono<T> mono, Function<? super T, ? extends Iterable<? extends S>> function) {
+      return Refaster.anyOf(
+          mono.map(function).flatMapIterable(identity()), mono.flux().concatMapIterable(function));
+    }
+
+    @AfterTemplate
+    Flux<S> after(Mono<T> mono, Function<? super T, ? extends Iterable<? extends S>> function) {
+      return mono.flatMapIterable(function);
+    }
+  }
+
   /**
-   * Prefer {@link Flux#concatMapIterable(Function)} over {@link Flux#flatMapIterable(Function)}, as
-   * the former has equivalent semantics but a clearer name.
+   * Prefer {@link Mono#flatMapIterable(Function)} to flatten a {@link Mono} of some {@link
+   * Iterable} over less efficient alternatives.
+   */
+  static final class MonoFlatMapIterableIdentity<T, S extends Iterable<T>> {
+    @BeforeTemplate
+    Flux<T> before(Mono<S> mono) {
+      return mono.flatMapMany(Flux::fromIterable);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    Flux<T> after(Mono<S> mono) {
+      return mono.flatMapIterable(identity());
+    }
+  }
+
+  /**
+   * Prefer {@link Flux#concatMapIterable(Function)} over alternatives with less clear syntax or
+   * semantics.
    */
   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);
+      return Refaster.anyOf(
+          flux.flatMapIterable(function), flux.map(function).concatMapIterable(identity()));
     }
 
     @AfterTemplate
@@ -484,14 +637,16 @@ final class ReactorRules {
   }
 
   /**
-   * Prefer {@link Flux#concatMapIterable(Function, int)} over {@link Flux#flatMapIterable(Function,
-   * int)}, as the former has equivalent semantics but a clearer name.
+   * Prefer {@link Flux#concatMapIterable(Function, int)} over alternatives with less clear syntax
+   * or semantics.
    */
   static final class FluxConcatMapIterableWithPrefetch<T, S> {
     @BeforeTemplate
     Flux<S> before(
         Flux<T> flux, Function<? super T, ? extends Iterable<? extends S>> function, int prefetch) {
-      return flux.flatMapIterable(function, prefetch);
+      return Refaster.anyOf(
+          flux.flatMapIterable(function, prefetch),
+          flux.map(function).concatMapIterable(identity(), prefetch));
     }
 
     @AfterTemplate
@@ -723,7 +878,7 @@ final class ReactorRules {
   static final class MonoThen<T> {
     @BeforeTemplate
     Mono<@Nullable Void> before(Mono<T> mono) {
-      return mono.flux().then();
+      return Refaster.anyOf(mono.ignoreElement().then(), mono.flux().then());
     }
 
     @AfterTemplate
@@ -732,6 +887,128 @@ final class ReactorRules {
     }
   }
 
+  /** Avoid vacuous invocations of {@link Flux#ignoreElements()}. */
+  static final class FluxThen<T> {
+    @BeforeTemplate
+    Mono<@Nullable Void> before(Flux<T> flux) {
+      return flux.ignoreElements().then();
+    }
+
+    @BeforeTemplate
+    Mono<@Nullable Void> before2(Flux<@Nullable Void> flux) {
+      return flux.ignoreElements();
+    }
+
+    @AfterTemplate
+    Mono<@Nullable Void> after(Flux<T> flux) {
+      return flux.then();
+    }
+  }
+
+  /** Avoid vacuous invocations of {@link Mono#ignoreElement()}. */
+  static final class MonoThenEmpty<T> {
+    @BeforeTemplate
+    Mono<@Nullable Void> before(Mono<T> mono, Publisher<@Nullable Void> publisher) {
+      return mono.ignoreElement().thenEmpty(publisher);
+    }
+
+    @AfterTemplate
+    Mono<@Nullable Void> after(Mono<T> mono, Publisher<@Nullable Void> publisher) {
+      return mono.thenEmpty(publisher);
+    }
+  }
+
+  /** Avoid vacuous invocations of {@link Flux#ignoreElements()}. */
+  static final class FluxThenEmpty<T> {
+    @BeforeTemplate
+    Mono<@Nullable Void> before(Flux<T> flux, Publisher<@Nullable Void> publisher) {
+      return flux.ignoreElements().thenEmpty(publisher);
+    }
+
+    @AfterTemplate
+    Mono<@Nullable Void> after(Flux<T> flux, Publisher<@Nullable Void> publisher) {
+      return flux.thenEmpty(publisher);
+    }
+  }
+
+  /** Avoid vacuous invocations of {@link Mono#ignoreElement()}. */
+  static final class MonoThenMany<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Mono<T> mono, Publisher<S> publisher) {
+      return mono.ignoreElement().thenMany(publisher);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Mono<T> mono, Publisher<S> publisher) {
+      return mono.thenMany(publisher);
+    }
+  }
+
+  /**
+   * Prefer explicit invocation of {@link Mono#flux()} over implicit conversions from {@link Mono}
+   * to {@link Flux}.
+   */
+  static final class MonoThenMonoFlux<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Mono<T> mono1, Mono<S> mono2) {
+      return mono1.thenMany(mono2);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Mono<T> mono1, Mono<S> mono2) {
+      return mono1.then(mono2).flux();
+    }
+  }
+
+  /** Avoid vacuous invocations of {@link Flux#ignoreElements()}. */
+  static final class FluxThenMany<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<T> flux, Publisher<S> publisher) {
+      return flux.ignoreElements().thenMany(publisher);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Flux<T> flux, Publisher<S> publisher) {
+      return flux.thenMany(publisher);
+    }
+  }
+
+  /** Avoid vacuous invocations of {@link Mono#ignoreElement()}. */
+  static final class MonoThenMono<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Mono<T> mono1, Mono<S> mono2) {
+      return mono1.ignoreElement().then(mono2);
+    }
+
+    @BeforeTemplate
+    Mono<@Nullable Void> before2(Mono<T> mono1, Mono<@Nullable Void> mono2) {
+      return mono1.thenEmpty(mono2);
+    }
+
+    @AfterTemplate
+    Mono<S> after(Mono<T> mono1, Mono<S> mono2) {
+      return mono1.then(mono2);
+    }
+  }
+
+  /** Avoid vacuous invocations of {@link Flux#ignoreElements()}. */
+  static final class FluxThenMono<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Flux<T> flux, Mono<S> mono) {
+      return flux.ignoreElements().then(mono);
+    }
+
+    @BeforeTemplate
+    Mono<@Nullable Void> before2(Flux<T> flux, Mono<@Nullable Void> mono) {
+      return flux.thenEmpty(mono);
+    }
+
+    @AfterTemplate
+    Mono<S> after(Flux<T> flux, Mono<S> mono) {
+      return flux.then(mono);
+    }
+  }
+
   /** Prefer {@link Mono#singleOptional()} over more contrived alternatives. */
   // XXX: Consider creating a plugin that flags/discourages `Mono<Optional<T>>` method return
   // types, just as we discourage nullable `Boolean`s and `Optional`s.
@@ -776,9 +1053,36 @@ final class ReactorRules {
     }
   }
 
+  /** Prefer {@link Mono#ofType(Class)} over more contrived alternatives. */
+  static final class MonoOfType<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Mono<T> mono, Class<S> clazz) {
+      return mono.filter(clazz::isInstance).cast(clazz);
+    }
+
+    @AfterTemplate
+    Mono<S> after(Mono<T> mono, Class<S> clazz) {
+      return mono.ofType(clazz);
+    }
+  }
+
+  /** Prefer {@link Flux#ofType(Class)} over more contrived alternatives. */
+  static final class FluxOfType<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<T> flux, Class<S> clazz) {
+      return flux.filter(clazz::isInstance).cast(clazz);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Flux<T> flux, Class<S> clazz) {
+      return flux.ofType(clazz);
+    }
+  }
+
   /** Prefer {@link Mono#flatMap(Function)} over more contrived alternatives. */
   static final class MonoFlatMap<S, T> {
     @BeforeTemplate
+    @SuppressWarnings("NestedPublishers")
     Mono<T> before(Mono<S> mono, Function<? super S, ? extends Mono<? extends T>> function) {
       return mono.map(function).flatMap(identity());
     }
@@ -792,8 +1096,31 @@ final class ReactorRules {
   /** Prefer {@link Mono#flatMapMany(Function)} over more contrived alternatives. */
   static final class MonoFlatMapMany<S, T> {
     @BeforeTemplate
-    Flux<T> before(Mono<S> mono, Function<? super S, ? extends Publisher<? extends T>> function) {
-      return mono.map(function).flatMapMany(identity());
+    @SuppressWarnings("NestedPublishers")
+    Flux<T> before(
+        Mono<S> mono,
+        Function<? super S, ? extends Publisher<? extends T>> function,
+        boolean delayUntilEnd,
+        int maxConcurrency,
+        int prefetch) {
+      return Refaster.anyOf(
+          mono.map(function).flatMapMany(identity()),
+          mono.flux().concatMap(function),
+          mono.flux().concatMap(function, prefetch),
+          mono.flux().concatMapDelayError(function),
+          mono.flux().concatMapDelayError(function, prefetch),
+          mono.flux().concatMapDelayError(function, delayUntilEnd, prefetch),
+          mono.flux().flatMap(function, maxConcurrency),
+          mono.flux().flatMap(function, maxConcurrency, prefetch),
+          mono.flux().flatMapDelayError(function, maxConcurrency, prefetch),
+          mono.flux().flatMapSequential(function, maxConcurrency),
+          mono.flux().flatMapSequential(function, maxConcurrency, prefetch),
+          mono.flux().flatMapSequentialDelayError(function, maxConcurrency, prefetch));
+    }
+
+    @BeforeTemplate
+    Flux<T> before(Mono<S> mono, Function<? super S, Publisher<? extends T>> function) {
+      return mono.flux().switchMap(function);
     }
 
     @AfterTemplate
@@ -1177,6 +1504,22 @@ final class ReactorRules {
     }
   }
 
+  /**
+   * Do not unnecessarily {@link Flux#filter(Predicate) filter} the result of {@link
+   * Flux#takeWhile(Predicate)} using the same {@link Predicate}.
+   */
+  static final class FluxTakeWhile<T> {
+    @BeforeTemplate
+    Flux<T> before(Flux<T> flux, Predicate<? super T> predicate) {
+      return flux.takeWhile(predicate).filter(predicate);
+    }
+
+    @AfterTemplate
+    Flux<T> after(Flux<T> flux, Predicate<? super T> predicate) {
+      return flux.takeWhile(predicate);
+    }
+  }
+
   /**
    * Prefer {@link Flux#collect(Collector)} with {@link ImmutableList#toImmutableList()} over
    * alternatives that do not explicitly return an immutable collection.
@@ -1276,6 +1619,7 @@ final class ReactorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     StepVerifier.Step<T> after(StepVerifier.Step<T> step) {
       return step;
     }
@@ -1295,6 +1639,23 @@ final class ReactorRules {
     }
   }
 
+  /** Avoid list collection when verifying that a {@link Flux} emits exactly one value. */
+  // XXX: This rule assumes that the matched collector does not drop elements. Consider introducing
+  // a `@Matches(DoesNotDropElements.class)` or `@NotMatches(MayDropElements.class)` guard.
+  static final class FluxAsStepVerifierExpectNext<T, L extends List<T>> {
+    @BeforeTemplate
+    StepVerifier.Step<L> before(Flux<T> flux, Collector<? super T, ?, L> listCollector, T object) {
+      return flux.collect(listCollector)
+          .as(StepVerifier::create)
+          .assertNext(list -> assertThat(list).containsExactly(object));
+    }
+
+    @AfterTemplate
+    StepVerifier.Step<T> after(Flux<T> flux, T object) {
+      return flux.as(StepVerifier::create).expectNext(object);
+    }
+  }
+
   /** Prefer {@link StepVerifier.LastStep#verifyComplete()} over more verbose alternatives. */
   static final class StepVerifierLastStepVerifyComplete {
     @BeforeTemplate
@@ -1327,6 +1688,7 @@ final class ReactorRules {
     Duration before(StepVerifier.LastStep step, Class<T> clazz) {
       return Refaster.anyOf(
           step.expectError(clazz).verify(),
+          step.verifyErrorMatches(clazz::isInstance),
           step.verifyErrorSatisfies(t -> assertThat(t).isInstanceOf(clazz)));
     }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java

@@ -3,6 +3,7 @@ package tech.picnic.errorprone.refasterrules;
 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.Function.identity;
 import static java.util.function.Predicate.not;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.filtering;
@@ -19,13 +20,17 @@ import static java.util.stream.Collectors.summingDouble;
 import static java.util.stream.Collectors.summingInt;
 import static java.util.stream.Collectors.summingLong;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 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.Matches;
 import com.google.errorprone.refaster.annotation.MayOptionallyUse;
+import com.google.errorprone.refaster.annotation.NotMatches;
 import com.google.errorprone.refaster.annotation.Placeholder;
+import com.google.errorprone.refaster.annotation.Repeated;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Arrays;
 import java.util.Collection;
@@ -41,11 +46,13 @@ import java.util.function.Predicate;
 import java.util.function.ToDoubleFunction;
 import java.util.function.ToIntFunction;
 import java.util.function.ToLongFunction;
+import java.util.function.UnaryOperator;
 import java.util.stream.Collector;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 import tech.picnic.errorprone.refaster.matchers.IsLambdaExpressionOrMethodReference;
+import tech.picnic.errorprone.refaster.matchers.IsRefasterAsVarargs;
 
 /** Refaster rules related to expressions dealing with {@link Stream}s. */
 @OnlineDocumentation
@@ -100,12 +107,9 @@ final class StreamRules {
    * Prefer {@link Arrays#stream(Object[])} over {@link Stream#of(Object[])}, as the former is
    * clearer.
    */
-  // XXX: Introduce a `Matcher` that identifies `Refaster.asVarargs(...)` invocations and annotate
-  // the `array` parameter as `@NotMatches(IsRefasterAsVarargs.class)`. Then elsewhere
-  // `@SuppressWarnings("StreamOfArray")` annotations can be dropped.
   static final class StreamOfArray<T> {
     @BeforeTemplate
-    Stream<T> before(T[] array) {
+    Stream<T> before(@NotMatches(IsRefasterAsVarargs.class) T[] array) {
       return Stream.of(array);
     }
 
@@ -123,6 +127,7 @@ final class StreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Stream<T> after(Stream<T> stream) {
       return stream;
     }
@@ -624,4 +629,114 @@ final class StreamRules {
       return stream.flatMap(mapper).collect(collector);
     }
   }
+
+  static final class StreamsConcat<T> {
+    @BeforeTemplate
+    Stream<T> before(@Repeated Stream<T> stream) {
+      return Stream.of(Refaster.asVarargs(stream)).flatMap(Refaster.anyOf(identity(), s -> s));
+    }
+
+    @AfterTemplate
+    Stream<T> after(@Repeated Stream<T> stream) {
+      return Streams.concat(Refaster.asVarargs(stream));
+    }
+  }
+
+  static final class StreamTakeWhile<T> {
+    @BeforeTemplate
+    Stream<T> before(Stream<T> stream, Predicate<? super T> predicate) {
+      return stream.takeWhile(predicate).filter(predicate);
+    }
+
+    @AfterTemplate
+    Stream<T> after(Stream<T> stream, Predicate<? super T> predicate) {
+      return stream.takeWhile(predicate);
+    }
+  }
+
+  /**
+   * Prefer {@link Stream#iterate(Object, Predicate, UnaryOperator)} over more contrived
+   * alternatives.
+   */
+  static final class StreamIterate<T> {
+    @BeforeTemplate
+    Stream<T> before(T seed, Predicate<? super T> hasNext, UnaryOperator<T> next) {
+      return Stream.iterate(seed, next).takeWhile(hasNext);
+    }
+
+    @AfterTemplate
+    Stream<T> after(T seed, Predicate<? super T> hasNext, UnaryOperator<T> next) {
+      return Stream.iterate(seed, hasNext, next);
+    }
+  }
+
+  /** Prefer {@link Stream#of(Object)} over more contrived alternatives. */
+  // XXX: Generalize this and similar rules using an Error Prone check.
+  static final class StreamOf1<T> {
+    @BeforeTemplate
+    Stream<T> before(T e1) {
+      return ImmutableList.of(e1).stream();
+    }
+
+    @AfterTemplate
+    Stream<T> after(T e1) {
+      return Stream.of(e1);
+    }
+  }
+
+  /** Prefer {@link Stream#of(Object[])} over more contrived alternatives. */
+  // XXX: Generalize this and similar rules using an Error Prone check.
+  static final class StreamOf2<T> {
+    @BeforeTemplate
+    Stream<T> before(T e1, T e2) {
+      return ImmutableList.of(e1, e2).stream();
+    }
+
+    @AfterTemplate
+    Stream<T> after(T e1, T e2) {
+      return Stream.of(e1, e2);
+    }
+  }
+
+  /** Prefer {@link Stream#of(Object[])} over more contrived alternatives. */
+  // XXX: Generalize this and similar rules using an Error Prone check.
+  static final class StreamOf3<T> {
+    @BeforeTemplate
+    Stream<T> before(T e1, T e2, T e3) {
+      return ImmutableList.of(e1, e2, e3).stream();
+    }
+
+    @AfterTemplate
+    Stream<T> after(T e1, T e2, T e3) {
+      return Stream.of(e1, e2, e3);
+    }
+  }
+
+  /** Prefer {@link Stream#of(Object[])} over more contrived alternatives. */
+  // XXX: Generalize this and similar rules using an Error Prone check.
+  static final class StreamOf4<T> {
+    @BeforeTemplate
+    Stream<T> before(T e1, T e2, T e3, T e4) {
+      return ImmutableList.of(e1, e2, e3, e4).stream();
+    }
+
+    @AfterTemplate
+    Stream<T> after(T e1, T e2, T e3, T e4) {
+      return Stream.of(e1, e2, e3, e4);
+    }
+  }
+
+  /** Prefer {@link Stream#of(Object[])} over more contrived alternatives. */
+  // XXX: Generalize this and similar rules using an Error Prone check.
+  static final class StreamOf5<T> {
+    @BeforeTemplate
+    Stream<T> before(T e1, T e2, T e3, T e4, T e5) {
+      return ImmutableList.of(e1, e2, e3, e4, e5).stream();
+    }
+
+    @AfterTemplate
+    Stream<T> after(T e1, T e2, T e3, T e4, T e5) {
+      return Stream.of(e1, e2, e3, e4, e5);
+    }
+  }
 }

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

@@ -1,7 +1,5 @@
 package tech.picnic.errorprone.bugpatterns;
 
-import static com.google.common.base.Predicates.containsPattern;
-
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
@@ -12,7 +10,7 @@ final class AmbiguousJsonCreatorTest {
   void identification() {
     CompilationTestHelper.newInstance(AmbiguousJsonCreator.class, getClass())
         .expectErrorMessage(
-            "X", containsPattern("`JsonCreator.Mode` should be set for single-argument creators"))
+            "X", m -> m.contains("`JsonCreator.Mode` should be set for single-argument creators"))
         .addSourceLines(
             "Container.java",
             "import com.fasterxml.jackson.annotation.JsonCreator;",

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

@@ -1,8 +1,7 @@
 package tech.picnic.errorprone.bugpatterns;
 
-import static com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH;
-
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
@@ -54,6 +53,6 @@ final class AssertJIsNullTest {
             "    assertThat(\"foo\").isNull();",
             "  }",
             "}")
-        .doTest(TEXT_MATCH);
+        .doTest(TestMode.TEXT_MATCH);
   }
 }

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

@@ -1,14 +1,12 @@
 package tech.picnic.errorprone.bugpatterns;
 
-import static com.google.common.base.Predicates.and;
-import static com.google.common.base.Predicates.containsPattern;
-import static com.google.common.base.Predicates.not;
 import static com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers.SECOND;
 import static com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers.THIRD;
 
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
+import java.util.stream.Stream;
 import org.junit.jupiter.api.Test;
 import org.reactivestreams.Publisher;
 import reactor.core.CorePublisher;
@@ -20,10 +18,7 @@ final class FluxImplicitBlockTest {
     CompilationTestHelper.newInstance(FluxImplicitBlock.class, getClass())
         .expectErrorMessage(
             "X",
-            and(
-                containsPattern("SuppressWarnings"),
-                containsPattern("toImmutableList"),
-                containsPattern("toList")))
+            m -> Stream.of("SuppressWarnings", "toImmutableList", "toList").allMatch(m::contains))
         .addSourceLines(
             "A.java",
             "import com.google.common.collect.ImmutableList;",
@@ -63,7 +58,7 @@ final class FluxImplicitBlockTest {
   void identificationWithoutGuavaOnClasspath() {
     CompilationTestHelper.newInstance(FluxImplicitBlock.class, getClass())
         .withClasspath(CorePublisher.class, Flux.class, Publisher.class)
-        .expectErrorMessage("X", not(containsPattern("toImmutableList")))
+        .expectErrorMessage("X", m -> !m.contains("toImmutableList"))
         .addSourceLines(
             "A.java",
             "import reactor.core.publisher.Flux;",

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

@@ -1,89 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.common.base.Predicates.containsPattern;
-
-import com.google.errorprone.CompilationTestHelper;
-import org.junit.jupiter.api.Test;
-
-final class MissingRefasterAnnotationTest {
-  @Test
-  void identification() {
-    CompilationTestHelper.newInstance(MissingRefasterAnnotation.class, getClass())
-        .expectErrorMessage(
-            "X",
-            containsPattern("The Refaster rule contains a method without any Refaster annotations"))
-        .addSourceLines(
-            "A.java",
-            "import com.google.errorprone.refaster.annotation.AfterTemplate;",
-            "import com.google.errorprone.refaster.annotation.AlsoNegation;",
-            "import com.google.errorprone.refaster.annotation.BeforeTemplate;",
-            "import java.util.Map;",
-            "",
-            "class A {",
-            "  // BUG: Diagnostic matches: X",
-            "  static final class MethodLacksBeforeTemplateAnnotation {",
-            "    @BeforeTemplate",
-            "    boolean before1(String string) {",
-            "      return string.equals(\"\");",
-            "    }",
-            "",
-            "    // @BeforeTemplate is missing",
-            "    boolean before2(String string) {",
-            "      return string.length() == 0;",
-            "    }",
-            "",
-            "    @AfterTemplate",
-            "    @AlsoNegation",
-            "    boolean after(String string) {",
-            "      return string.isEmpty();",
-            "    }",
-            "  }",
-            "",
-            "  // BUG: Diagnostic matches: X",
-            "  static final class MethodLacksAfterTemplateAnnotation {",
-            "    @BeforeTemplate",
-            "    boolean before(String string) {",
-            "      return string.equals(\"\");",
-            "    }",
-            "",
-            "    // @AfterTemplate is missing",
-            "    boolean after(String string) {",
-            "      return string.isEmpty();",
-            "    }",
-            "  }",
-            "",
-            "  // BUG: Diagnostic matches: X",
-            "  abstract class MethodLacksPlaceholderAnnotation<K, V> {",
-            "    // @Placeholder is missing",
-            "    abstract V function(K key);",
-            "",
-            "    @BeforeTemplate",
-            "    void before(Map<K, V> map, K key) {",
-            "      if (!map.containsKey(key)) {",
-            "        map.put(key, function(key));",
-            "      }",
-            "    }",
-            "",
-            "    @AfterTemplate",
-            "    void after(Map<K, V> map, K key) {",
-            "      map.computeIfAbsent(key, k -> function(k));",
-            "    }",
-            "  }",
-            "",
-            "  static final class ValidRefasterRule {",
-            "    @BeforeTemplate",
-            "    void unusedPureFunctionCall(Object o) {",
-            "      o.toString();",
-            "    }",
-            "  }",
-            "",
-            "  static final class NotARefasterRule {",
-            "    @Override",
-            "    public String toString() {",
-            "      return \"This is not a Refaster rule\";",
-            "    }",
-            "  }",
-            "}")
-        .doTest();
-  }
-}

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

@@ -0,0 +1,26 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class MongoDBTextFilterUsageTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(MongoDBTextFilterUsage.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import com.mongodb.client.model.Filters;",
+            "import com.mongodb.client.model.TextSearchOptions;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Filters.eq(\"foo\", \"bar\");",
+            "    // BUG: Diagnostic contains:",
+            "    Filters.text(\"foo\");",
+            "    // BUG: Diagnostic contains:",
+            "    Filters.text(\"foo\", new TextSearchOptions());",
+            "  }",
+            "}")
+        .doTest();
+  }
+}

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

@@ -36,19 +36,4 @@ final class NestedOptionalsTest {
             "}")
         .doTest();
   }
-
-  @Test
-  void identificationOptionalTypeNotLoaded() {
-    CompilationTestHelper.newInstance(NestedOptionals.class, getClass())
-        .addSourceLines(
-            "A.java",
-            "import java.time.Duration;",
-            "",
-            "class A {",
-            "  void m() {",
-            "    Duration.ofSeconds(1);",
-            "  }",
-            "}")
-        .doTest();
-  }
 }

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

@@ -0,0 +1,37 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class NestedPublishersTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(NestedPublishers.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import org.reactivestreams.Publisher;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.core.publisher.GroupedFlux;",
+            "import reactor.core.publisher.Mono;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Mono.empty();",
+            "    Flux.just(1);",
+            "    Flux.just(1, 2).groupBy(i -> i).map(groupedFlux -> (GroupedFlux) groupedFlux);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Mono.just(Mono.empty());",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(Flux.empty());",
+            "    // BUG: Diagnostic contains:",
+            "    Mono.just((Flux) Flux.just(1));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just((Publisher) Mono.just(1));",
+            "    // BUG: Diagnostic contains:",
+            "    Mono.just(1).map(Mono::just);",
+            "  }",
+            "}")
+        .doTest();
+  }
+}

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

@@ -1,8 +1,7 @@
 package tech.picnic.errorprone.bugpatterns;
 
-import static com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH;
-
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
@@ -145,6 +144,6 @@ final class NonEmptyMonoTest {
             "    Mono.just(2).hasElement();",
             "  }",
             "}")
-        .doTest(TEXT_MATCH);
+        .doTest(TestMode.TEXT_MATCH);
   }
 }

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

@@ -9,12 +9,12 @@ final class RequestMappingAnnotationTest {
     CompilationTestHelper.newInstance(RequestMappingAnnotation.class, getClass())
         .addSourceLines(
             "A.java",
+            "import jakarta.servlet.http.HttpServletRequest;",
+            "import jakarta.servlet.http.HttpServletResponse;",
             "import java.io.InputStream;",
             "import java.time.ZoneId;",
             "import java.util.Locale;",
             "import java.util.TimeZone;",
-            "import javax.servlet.http.HttpServletRequest;",
-            "import javax.servlet.http.HttpServletResponse;",
             "import org.springframework.http.HttpMethod;",
             "import org.springframework.ui.Model;",
             "import org.springframework.validation.BindingResult;",

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

@@ -1,105 +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;
-import org.springframework.scheduling.annotation.Scheduled;
-
-final class ScheduledTransactionTraceTest {
-  @Test
-  void identification() {
-    CompilationTestHelper.newInstance(ScheduledTransactionTrace.class, getClass())
-        .addSourceLines(
-            "A.java",
-            "import com.newrelic.api.agent.Trace;",
-            "import org.springframework.scheduling.annotation.Scheduled;",
-            "",
-            "class A {",
-            "  void notScheduled() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  // BUG: Diagnostic contains:",
-            "  void scheduledButNotTraced() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  // BUG: Diagnostic contains:",
-            "  @Trace",
-            "  void scheduledButImproperlyTraced1() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  // BUG: Diagnostic contains:",
-            "  @Trace(dispatcher = false)",
-            "  void scheduledButImproperlyTraced2() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  @Trace(dispatcher = true)",
-            "  void scheduledAndProperlyTraced() {}",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void identificationWithoutNewRelicAgentApiOnClasspath() {
-    CompilationTestHelper.newInstance(ScheduledTransactionTrace.class, getClass())
-        .withClasspath(Scheduled.class)
-        .addSourceLines(
-            "A.java",
-            "import org.springframework.scheduling.annotation.Scheduled;",
-            "",
-            "class A {",
-            "  @Scheduled(fixedDelay = 1)",
-            "  void scheduledButNotTraced() {}",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void replacement() {
-    BugCheckerRefactoringTestHelper.newInstance(ScheduledTransactionTrace.class, getClass())
-        .addInputLines(
-            "A.java",
-            "import com.newrelic.api.agent.Trace;",
-            "import org.springframework.scheduling.annotation.Scheduled;",
-            "",
-            "class A {",
-            "  @Scheduled(fixedDelay = 1)",
-            "  void scheduledButNotTraced() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  @Trace",
-            "  void scheduledButImproperlyTraced1() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  @Trace(dispatcher = false)",
-            "  void scheduledButImproperlyTraced2() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  @Trace(leaf = true)",
-            "  void scheduledButImproperlyTraced3() {}",
-            "}")
-        .addOutputLines(
-            "A.java",
-            "import com.newrelic.api.agent.Trace;",
-            "import org.springframework.scheduling.annotation.Scheduled;",
-            "",
-            "class A {",
-            "  @Trace(dispatcher = true)",
-            "  @Scheduled(fixedDelay = 1)",
-            "  void scheduledButNotTraced() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  @Trace(dispatcher = true)",
-            "  void scheduledButImproperlyTraced1() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  @Trace(dispatcher = true)",
-            "  void scheduledButImproperlyTraced2() {}",
-            "",
-            "  @Scheduled(fixedDelay = 1)",
-            "  @Trace(dispatcher = true, leaf = true)",
-            "  void scheduledButImproperlyTraced3() {}",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-}

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

@@ -1,124 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import com.google.errorprone.BugCheckerRefactoringTestHelper;
-import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
-import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
-import com.google.errorprone.CompilationTestHelper;
-import org.junit.jupiter.api.Test;
-
-final class StringCaseLocaleUsageTest {
-  @Test
-  void identification() {
-    CompilationTestHelper.newInstance(StringCaseLocaleUsage.class, getClass())
-        .addSourceLines(
-            "A.java",
-            "import static java.util.Locale.ROOT;",
-            "",
-            "import java.util.Locale;",
-            "",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(Locale.ROOT);",
-            "    \"a\".toUpperCase(Locale.ROOT);",
-            "    \"b\".toLowerCase(ROOT);",
-            "    \"b\".toUpperCase(ROOT);",
-            "    \"c\".toLowerCase(Locale.getDefault());",
-            "    \"c\".toUpperCase(Locale.getDefault());",
-            "    \"d\".toLowerCase(Locale.ENGLISH);",
-            "    \"d\".toUpperCase(Locale.ENGLISH);",
-            "    \"e\".toLowerCase(new Locale(\"foo\"));",
-            "    \"e\".toUpperCase(new Locale(\"foo\"));",
-            "",
-            "    // BUG: Diagnostic contains:",
-            "    \"f\".toLowerCase();",
-            "    // BUG: Diagnostic contains:",
-            "    \"g\".toUpperCase();",
-            "",
-            "    String h = \"h\";",
-            "    // BUG: Diagnostic contains:",
-            "    h.toLowerCase();",
-            "    String i = \"i\";",
-            "    // BUG: Diagnostic contains:",
-            "    i.toUpperCase();",
-            "  }",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void replacementFirstSuggestedFix() {
-    BugCheckerRefactoringTestHelper.newInstance(StringCaseLocaleUsage.class, getClass())
-        .addInputLines(
-            "A.java",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(/* Comment with parens: (). */ );",
-            "    \"b\".toUpperCase();",
-            "    \"c\".toLowerCase().toString();",
-            "",
-            "    toString().toLowerCase();",
-            "    toString().toUpperCase /* Comment with parens: (). */();",
-            "",
-            "    this.toString().toLowerCase() /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase();",
-            "  }",
-            "}")
-        .addOutputLines(
-            "A.java",
-            "import java.util.Locale;",
-            "",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(/* Comment with parens: (). */ Locale.ROOT);",
-            "    \"b\".toUpperCase(Locale.ROOT);",
-            "    \"c\".toLowerCase(Locale.ROOT).toString();",
-            "",
-            "    toString().toLowerCase(Locale.ROOT);",
-            "    toString().toUpperCase /* Comment with parens: (). */(Locale.ROOT);",
-            "",
-            "    this.toString().toLowerCase(Locale.ROOT) /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase(Locale.ROOT);",
-            "  }",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-
-  @Test
-  void replacementSecondSuggestedFix() {
-    BugCheckerRefactoringTestHelper.newInstance(StringCaseLocaleUsage.class, getClass())
-        .setFixChooser(FixChoosers.SECOND)
-        .addInputLines(
-            "A.java",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase();",
-            "    \"b\".toUpperCase(/* Comment with parens: (). */ );",
-            "    \"c\".toLowerCase().toString();",
-            "",
-            "    toString().toLowerCase();",
-            "    toString().toUpperCase /* Comment with parens: (). */();",
-            "",
-            "    this.toString().toLowerCase() /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase();",
-            "  }",
-            "}")
-        .addOutputLines(
-            "A.java",
-            "import java.util.Locale;",
-            "",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(Locale.getDefault());",
-            "    \"b\".toUpperCase(/* Comment with parens: (). */ Locale.getDefault());",
-            "    \"c\".toLowerCase(Locale.getDefault()).toString();",
-            "",
-            "    toString().toLowerCase(Locale.getDefault());",
-            "    toString().toUpperCase /* Comment with parens: (). */(Locale.getDefault());",
-            "",
-            "    this.toString().toLowerCase(Locale.getDefault()) /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase(Locale.getDefault());",
-            "  }",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-}

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

@@ -1,7 +1,5 @@
 package tech.picnic.errorprone.bugpatterns;
 
-import static com.google.common.base.Predicates.containsPattern;
-
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
@@ -12,8 +10,8 @@ final class StringJoinTest {
   void identification() {
     CompilationTestHelper.newInstance(StringJoin.class, getClass())
         .expectErrorMessage(
-            "valueOf", containsPattern("Prefer `String#valueOf` over `String#format`"))
-        .expectErrorMessage("join", containsPattern("Prefer `String#join` over `String#format`"))
+            "valueOf", m -> m.contains("Prefer `String#valueOf` over `String#format`"))
+        .expectErrorMessage("join", m -> m.contains("Prefer `String#join` over `String#format`"))
         .addSourceLines(
             "A.java",
             "import java.util.Formattable;",

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

@@ -1,21 +1,29 @@
 package tech.picnic.errorprone.bugpatterns.util;
 
 import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.generic;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.subOf;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.type;
 
+import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.CompilationTestHelper;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.AnnotationTreeMatcher;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
 import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.suppliers.Supplier;
 import com.sun.source.tree.AnnotationTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.Tree;
 import org.junit.jupiter.api.Test;
 
 final class MoreMatchersTest {
   @Test
   void hasMetaAnnotation() {
-    CompilationTestHelper.newInstance(TestMatcher.class, getClass())
+    CompilationTestHelper.newInstance(HasMetaAnnotationTestChecker.class, getClass())
         .addSourceLines(
             "A.java",
             "import org.junit.jupiter.api.AfterAll;",
@@ -47,9 +55,59 @@ final class MoreMatchersTest {
         .doTest();
   }
 
-  /** A {@link BugChecker} that delegates to {@link MoreMatchers#hasMetaAnnotation(String)} . */
+  @Test
+  void isSubTypeOf() {
+    CompilationTestHelper.newInstance(IsSubTypeOfTestChecker.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.ImmutableSet;",
+            "import com.google.common.collect.ImmutableSortedSet;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    ImmutableSet.of(\"foo\");",
+            "    ImmutableSortedSet.of(\"foo\");",
+            "    ImmutableList.of(\"foo\");",
+            "    ImmutableList.of(1);",
+            "    ImmutableList.of(1.0);",
+            "    ImmutableList.of((Number) 1);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    ImmutableSet.of(1);",
+            "    // BUG: Diagnostic contains:",
+            "    ImmutableSet.of(1.0);",
+            "    // BUG: Diagnostic contains:",
+            "    ImmutableSet.of((Number) 1);",
+            "    // BUG: Diagnostic contains:",
+            "    ImmutableSortedSet.of(1);",
+            "    // BUG: Diagnostic contains:",
+            "    ImmutableSortedSet.of(1.0);",
+            "    // BUG: Diagnostic contains:",
+            "    ImmutableSortedSet.of((Number) 1);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void isSubTypeOfBoundTypeUnknown() {
+    CompilationTestHelper.newInstance(IsSubTypeOfTestChecker.class, getClass())
+        .withClasspath()
+        .addSourceLines(
+            "A.java",
+            "class A {",
+            "  void m() {",
+            "    System.out.println(toString());",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  /** A {@link BugChecker} that delegates to {@link MoreMatchers#hasMetaAnnotation(String)}. */
   @BugPattern(summary = "Interacts with `MoreMatchers` for testing purposes", severity = ERROR)
-  public static final class TestMatcher extends BugChecker implements AnnotationTreeMatcher {
+  public static final class HasMetaAnnotationTestChecker extends BugChecker
+      implements AnnotationTreeMatcher {
     private static final long serialVersionUID = 1L;
     private static final Matcher<AnnotationTree> DELEGATE =
         MoreMatchers.hasMetaAnnotation("org.junit.jupiter.api.TestTemplate");
@@ -59,4 +117,19 @@ final class MoreMatchersTest {
       return DELEGATE.matches(tree, state) ? describeMatch(tree) : Description.NO_MATCH;
     }
   }
+
+  /** A {@link BugChecker} that delegates to {@link MoreMatchers#isSubTypeOf(Supplier)}. */
+  @BugPattern(summary = "Interacts with `MoreMatchers` for testing purposes", severity = ERROR)
+  public static final class IsSubTypeOfTestChecker extends BugChecker
+      implements MethodInvocationTreeMatcher {
+    private static final long serialVersionUID = 1L;
+    private static final Matcher<Tree> DELEGATE =
+        MoreMatchers.isSubTypeOf(
+            generic(type(ImmutableSet.class.getName()), subOf(type(Number.class.getName()))));
+
+    @Override
+    public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+      return DELEGATE.matches(tree, state) ? describeMatch(tree) : Description.NO_MATCH;
+    }
+  }
 }

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

@@ -23,7 +23,7 @@ final class ThirdPartyLibraryTest {
     CompilationTestHelper.newInstance(TestChecker.class, getClass())
         .addSourceLines(
             "A.java",
-            "// BUG: Diagnostic contains: ASSERTJ: true, GUAVA: true, NEW_RELIC_AGENT_API: true, REACTOR: true",
+            "// BUG: Diagnostic contains: ASSERTJ: true, GUAVA: true, REACTOR: true",
             "class A {}")
         .doTest();
   }
@@ -34,16 +34,14 @@ final class ThirdPartyLibraryTest {
         .addSourceLines(
             "A.java",
             "import com.google.common.collect.ImmutableList;",
-            "import com.newrelic.api.agent.Agent;",
             "import org.assertj.core.api.Assertions;",
             "import reactor.core.publisher.Flux;",
             "",
-            "// BUG: Diagnostic contains: ASSERTJ: true, GUAVA: true, NEW_RELIC_AGENT_API: true, REACTOR: true",
+            "// BUG: Diagnostic contains: ASSERTJ: true, GUAVA: true, REACTOR: true",
             "class A {",
             "  void m(Class<?> clazz) {",
             "    m(Assertions.class);",
             "    m(ImmutableList.class);",
-            "    m(Agent.class);",
             "    m(Flux.class);",
             "  }",
             "}")
@@ -56,7 +54,7 @@ final class ThirdPartyLibraryTest {
         .withClasspath(ImmutableList.class, Flux.class)
         .addSourceLines(
             "A.java",
-            "// BUG: Diagnostic contains: ASSERTJ: false, GUAVA: true, NEW_RELIC_AGENT_API: false, REACTOR: true",
+            "// BUG: Diagnostic contains: ASSERTJ: false, GUAVA: true, REACTOR: true",
             "class A {}")
         .doTest();
   }
@@ -67,7 +65,7 @@ final class ThirdPartyLibraryTest {
         .withClasspath()
         .addSourceLines(
             "A.java",
-            "// BUG: Diagnostic contains: ASSERTJ: false, GUAVA: false, NEW_RELIC_AGENT_API: false, REACTOR:",
+            "// BUG: Diagnostic contains: ASSERTJ: false, GUAVA: false, REACTOR:",
             "// false",
             "class A {}")
         .doTest();
@@ -82,8 +80,8 @@ final class ThirdPartyLibraryTest {
         .addSourceLines(
             "A.java",
             String.format(
-                "// BUG: Diagnostic contains: ASSERTJ: %s, GUAVA: true, NEW_RELIC_AGENT_API: %s, REACTOR: true",
-                ignoreClassPath, ignoreClassPath),
+                "// BUG: Diagnostic contains: ASSERTJ: %s, GUAVA: true, REACTOR: true",
+                ignoreClassPath),
             "class A {}")
         .doTest();
   }

error-prone-contrib/src/test/java/tech/picnic/errorprone/refasterrules/RefasterRulesTest.java

@@ -36,10 +36,12 @@ final class RefasterRulesTest {
           AssortedRules.class,
           BigDecimalRules.class,
           BugCheckerRules.class,
+          ClassRules.class,
           CollectionRules.class,
           ComparatorRules.class,
           DoubleStreamRules.class,
           EqualityRules.class,
+          FileRules.class,
           ImmutableListRules.class,
           ImmutableListMultimapRules.class,
           ImmutableMapRules.class,
@@ -59,6 +61,7 @@ final class RefasterRulesTest {
           MultimapRules.class,
           NullRules.class,
           OptionalRules.class,
+          PatternRules.class,
           PreconditionsRules.class,
           PrimitiveRules.class,
           ReactorRules.class,

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ClassRulesTestInput.java

@@ -0,0 +1,26 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import java.io.IOException;
+import java.util.function.Predicate;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class ClassRulesTest implements RefasterRuleCollectionTestCase {
+  boolean testClassIsInstance() throws IOException {
+    return CharSequence.class.isAssignableFrom("foo".getClass());
+  }
+
+  ImmutableSet<Boolean> testInstanceof() throws IOException {
+    Class<?> clazz = CharSequence.class;
+    return ImmutableSet.of(CharSequence.class.isInstance("foo"), clazz.isInstance("bar"));
+  }
+
+  Predicate<String> testClassLiteralIsInstancePredicate() throws IOException {
+    return s -> s instanceof CharSequence;
+  }
+
+  Predicate<String> testClassReferenceIsInstancePredicate() throws IOException {
+    Class<?> clazz = CharSequence.class;
+    return s -> clazz.isInstance(s);
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ClassRulesTestOutput.java

@@ -0,0 +1,26 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableSet;
+import java.io.IOException;
+import java.util.function.Predicate;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class ClassRulesTest implements RefasterRuleCollectionTestCase {
+  boolean testClassIsInstance() throws IOException {
+    return CharSequence.class.isInstance("foo");
+  }
+
+  ImmutableSet<Boolean> testInstanceof() throws IOException {
+    Class<?> clazz = CharSequence.class;
+    return ImmutableSet.of("foo" instanceof CharSequence, clazz.isInstance("bar"));
+  }
+
+  Predicate<String> testClassLiteralIsInstancePredicate() throws IOException {
+    return CharSequence.class::isInstance;
+  }
+
+  Predicate<String> testClassReferenceIsInstancePredicate() throws IOException {
+    Class<?> clazz = CharSequence.class;
+    return clazz::isInstance;
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/CollectionRulesTestInput.java

@@ -36,6 +36,10 @@ final class CollectionRulesTest implements RefasterRuleCollectionTestCase {
     return ImmutableSet.of(Iterables.size(ImmutableSet.of(1)), ImmutableSet.of(2).asList().size());
   }
 
+  boolean testCollectionContains() {
+    return ImmutableSet.of("foo").stream().anyMatch("bar"::equals);
+  }
+
   boolean testCollectionAddAllToCollectionExpression() {
     return Iterables.addAll(new ArrayList<>(), ImmutableSet.of("foo"));
   }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/CollectionRulesTestOutput.java

@@ -36,6 +36,10 @@ final class CollectionRulesTest implements RefasterRuleCollectionTestCase {
     return ImmutableSet.of(ImmutableSet.of(1).size(), ImmutableSet.of(2).size());
   }
 
+  boolean testCollectionContains() {
+    return ImmutableSet.of("foo").contains("bar");
+  }
+
   boolean testCollectionAddAllToCollectionExpression() {
     return new ArrayList<>().addAll(ImmutableSet.of("foo"));
   }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/DoubleStreamRulesTestInput.java

@@ -96,4 +96,8 @@ final class DoubleStreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testDoubleStreamAllMatch2() {
     return DoubleStream.of(1).noneMatch(n -> !(n > 1));
   }
+
+  DoubleStream testDoubleStreamTakeWhile() {
+    return DoubleStream.of(1, 2, 3).takeWhile(i -> i < 2).filter(i -> i < 2);
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/DoubleStreamRulesTestOutput.java

@@ -95,4 +95,8 @@ final class DoubleStreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testDoubleStreamAllMatch2() {
     return DoubleStream.of(1).allMatch(n -> n > 1);
   }
+
+  DoubleStream testDoubleStreamTakeWhile() {
+    return DoubleStream.of(1, 2, 3).takeWhile(i -> i < 2);
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/EqualityRulesTestInput.java

@@ -1,16 +1,20 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static java.util.function.Predicate.not;
+
 import com.google.common.collect.BoundType;
 import com.google.common.collect.ImmutableSet;
 import java.math.RoundingMode;
 import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Predicate;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
 final class EqualityRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<Object> elidedTypesAndStaticImports() {
-    return ImmutableSet.of(Objects.class);
+    return ImmutableSet.of(Objects.class, Optional.class, not(null));
   }
 
   ImmutableSet<Boolean> testPrimitiveOrReferenceEquality() {
@@ -60,4 +64,20 @@ final class EqualityRulesTest implements RefasterRuleCollectionTestCase {
         !(3.0 != 4.0),
         !(BoundType.OPEN != BoundType.CLOSED));
   }
+
+  Predicate<String> testPredicateLambda() {
+    return not(v -> v.isEmpty());
+  }
+
+  boolean testEqualsLhsNullable() {
+    return Optional.ofNullable("foo").equals(Optional.of("bar"));
+  }
+
+  boolean testEqualsRhsNullable() {
+    return Optional.of("foo").equals(Optional.ofNullable("bar"));
+  }
+
+  boolean testEqualsLhsAndRhsNullable() {
+    return Optional.ofNullable("foo").equals(Optional.ofNullable("bar"));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/EqualityRulesTestOutput.java

@@ -1,16 +1,20 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static java.util.function.Predicate.not;
+
 import com.google.common.collect.BoundType;
 import com.google.common.collect.ImmutableSet;
 import java.math.RoundingMode;
 import java.util.Objects;
+import java.util.Optional;
+import java.util.function.Predicate;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
 final class EqualityRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<Object> elidedTypesAndStaticImports() {
-    return ImmutableSet.of(Objects.class);
+    return ImmutableSet.of(Objects.class, Optional.class, not(null));
   }
 
   ImmutableSet<Boolean> testPrimitiveOrReferenceEquality() {
@@ -60,4 +64,20 @@ final class EqualityRulesTest implements RefasterRuleCollectionTestCase {
         3.0 == 4.0,
         BoundType.OPEN == BoundType.CLOSED);
   }
+
+  Predicate<String> testPredicateLambda() {
+    return v -> !v.isEmpty();
+  }
+
+  boolean testEqualsLhsNullable() {
+    return "bar".equals("foo");
+  }
+
+  boolean testEqualsRhsNullable() {
+    return "foo".equals("bar");
+  }
+
+  boolean testEqualsLhsAndRhsNullable() {
+    return Objects.equals("foo", "bar");
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/FileRulesTestInput.java

@@ -0,0 +1,17 @@
+package tech.picnic.errorprone.refasterrules;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class FileRulesTest implements RefasterRuleCollectionTestCase {
+  String testFilesReadStringWithCharset() throws IOException {
+    return new String(Files.readAllBytes(Paths.get("foo")), StandardCharsets.ISO_8859_1);
+  }
+
+  String testFilesReadString() throws IOException {
+    return Files.readString(Paths.get("foo"), StandardCharsets.UTF_8);
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/FileRulesTestOutput.java

@@ -0,0 +1,17 @@
+package tech.picnic.errorprone.refasterrules;
+
+import java.io.IOException;
+import java.nio.charset.StandardCharsets;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class FileRulesTest implements RefasterRuleCollectionTestCase {
+  String testFilesReadStringWithCharset() throws IOException {
+    return Files.readString(Paths.get("foo"), StandardCharsets.ISO_8859_1);
+  }
+
+  String testFilesReadString() throws IOException {
+    return Files.readString(Paths.get("foo"));
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/IntStreamRulesTestInput.java

@@ -100,4 +100,8 @@ final class IntStreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testIntStreamAllMatch2() {
     return IntStream.of(1).noneMatch(n -> !(n > 1));
   }
+
+  IntStream testIntStreamTakeWhile() {
+    return IntStream.of(1, 2, 3).takeWhile(i -> i < 2).filter(i -> i < 2);
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/IntStreamRulesTestOutput.java

@@ -99,4 +99,8 @@ final class IntStreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testIntStreamAllMatch2() {
     return IntStream.of(1).allMatch(n -> n > 1);
   }
+
+  IntStream testIntStreamTakeWhile() {
+    return IntStream.of(1, 2, 3).takeWhile(i -> i < 2);
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/LongStreamRulesTestInput.java

@@ -100,4 +100,8 @@ final class LongStreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testLongStreamAllMatch2() {
     return LongStream.of(1).noneMatch(n -> !(n > 1));
   }
+
+  LongStream testLongStreamTakeWhile() {
+    return LongStream.of(1, 2, 3).takeWhile(i -> i < 2).filter(i -> i < 2);
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/LongStreamRulesTestOutput.java

@@ -99,4 +99,8 @@ final class LongStreamRulesTest implements RefasterRuleCollectionTestCase {
   boolean testLongStreamAllMatch2() {
     return LongStream.of(1).allMatch(n -> n > 1);
   }
+
+  LongStream testLongStreamTakeWhile() {
+    return LongStream.of(1, 2, 3).takeWhile(i -> i < 2);
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/MockitoRulesTestInput.java

@@ -5,6 +5,7 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 import com.google.common.collect.ImmutableSet;
+import org.mockito.invocation.InvocationOnMock;
 import org.mockito.verification.VerificationMode;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
@@ -21,4 +22,14 @@ final class MockitoRulesTest implements RefasterRuleCollectionTestCase {
   Object testVerifyOnce() {
     return verify(mock(Object.class), times(1));
   }
+
+  Object testInvocationOnMockGetArguments() {
+    return ((InvocationOnMock) null).getArguments()[0];
+  }
+
+  ImmutableSet<Number> testInvocationOnMockGetArgumentsWithTypeParameter() {
+    return ImmutableSet.of(
+        ((InvocationOnMock) null).getArgument(0, Integer.class),
+        (Double) ((InvocationOnMock) null).getArgument(1));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/MockitoRulesTestOutput.java

@@ -6,6 +6,7 @@ import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
 
 import com.google.common.collect.ImmutableSet;
+import org.mockito.invocation.InvocationOnMock;
 import org.mockito.verification.VerificationMode;
 import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
 
@@ -22,4 +23,14 @@ final class MockitoRulesTest implements RefasterRuleCollectionTestCase {
   Object testVerifyOnce() {
     return verify(mock(Object.class));
   }
+
+  Object testInvocationOnMockGetArguments() {
+    return ((InvocationOnMock) null).getArgument(0);
+  }
+
+  ImmutableSet<Number> testInvocationOnMockGetArgumentsWithTypeParameter() {
+    return ImmutableSet.of(
+        ((InvocationOnMock) null).<Integer>getArgument(0),
+        ((InvocationOnMock) null).<Double>getArgument(1));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/OptionalRulesTestInput.java

@@ -35,6 +35,12 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
     return Optional::get;
   }
 
+  ImmutableSet<Boolean> testOptionalEqualsOptional() {
+    return ImmutableSet.of(
+        Optional.of("foo").filter("bar"::equals).isPresent(),
+        Optional.of("baz").stream().anyMatch("qux"::equals));
+  }
+
   ImmutableSet<Optional<String>> testOptionalFirstIteratorElement() {
     return ImmutableSet.of(
         ImmutableSet.of("foo").iterator().hasNext()
@@ -73,6 +79,13 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
     return Optional.of("foo").orElseGet(() -> Optional.of("bar").orElseThrow());
   }
 
+  ImmutableSet<String> testOptionalOrElseGet() {
+    return ImmutableSet.of(
+        Optional.of("foo").orElse("bar"),
+        Optional.of("baz").orElse(toString()),
+        Optional.of("qux").orElse(String.valueOf(true)));
+  }
+
   ImmutableSet<Object> testStreamFlatMapOptional() {
     return ImmutableSet.of(
         Stream.of(Optional.empty()).filter(Optional::isPresent).map(Optional::orElseThrow),
@@ -99,7 +112,8 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
     return ImmutableSet.of(
         Optional.of("foo").map(Optional::of).orElse(Optional.of("bar")),
         Optional.of("baz").map(Optional::of).orElseGet(() -> Optional.of("qux")),
-        Stream.of(Optional.of("quux"), Optional.of("quuz")).flatMap(Optional::stream).findFirst());
+        Stream.of(Optional.of("quux"), Optional.of("quuz")).flatMap(Optional::stream).findFirst(),
+        Optional.of("corge").isPresent() ? Optional.of("corge") : Optional.of("grault"));
   }
 
   ImmutableSet<Optional<String>> testOptionalIdentity() {
@@ -119,4 +133,10 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
   Optional<String> testOptionalMap() {
     return Optional.of(1).stream().map(String::valueOf).findAny();
   }
+
+  ImmutableSet<Stream<String>> testOptionalStream() {
+    return ImmutableSet.of(
+        Optional.of("foo").map(Stream::of).orElse(Stream.empty()),
+        Optional.of("bar").map(Stream::of).orElseGet(Stream::empty));
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/OptionalRulesTestOutput.java

@@ -35,6 +35,12 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
     return Optional::orElseThrow;
   }
 
+  ImmutableSet<Boolean> testOptionalEqualsOptional() {
+    return ImmutableSet.of(
+        Optional.of("foo").equals(Optional.of("bar")),
+        Optional.of("baz").equals(Optional.of("qux")));
+  }
+
   ImmutableSet<Optional<String>> testOptionalFirstIteratorElement() {
     return ImmutableSet.of(
         stream(ImmutableSet.of("foo").iterator()).findFirst(),
@@ -70,6 +76,13 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
     return Optional.of("foo").or(() -> Optional.of("bar")).orElseThrow();
   }
 
+  ImmutableSet<String> testOptionalOrElseGet() {
+    return ImmutableSet.of(
+        Optional.of("foo").orElse("bar"),
+        Optional.of("baz").orElse(toString()),
+        Optional.of("qux").orElseGet(() -> String.valueOf(true)));
+  }
+
   ImmutableSet<Object> testStreamFlatMapOptional() {
     return ImmutableSet.of(
         Stream.of(Optional.empty()).flatMap(Optional::stream),
@@ -96,7 +109,8 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
     return ImmutableSet.of(
         Optional.of("foo").or(() -> Optional.of("bar")),
         Optional.of("baz").or(() -> Optional.of("qux")),
-        Optional.of("quux").or(() -> Optional.of("quuz")));
+        Optional.of("quux").or(() -> Optional.of("quuz")),
+        Optional.of("corge").or(() -> Optional.of("grault")));
   }
 
   ImmutableSet<Optional<String>> testOptionalIdentity() {
@@ -112,4 +126,8 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
   Optional<String> testOptionalMap() {
     return Optional.of(1).map(String::valueOf);
   }
+
+  ImmutableSet<Stream<String>> testOptionalStream() {
+    return ImmutableSet.of(Optional.of("foo").stream(), Optional.of("bar").stream());
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/PatternRulesTestInput.java

@@ -0,0 +1,22 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.base.Predicates;
+import com.google.common.collect.ImmutableSet;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class PatternRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<Object> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(Predicates.class);
+  }
+
+  Predicate<?> testPatternAsPredicate() {
+    return Predicates.contains(Pattern.compile("foo"));
+  }
+
+  Predicate<?> testPatternCompileAsPredicate() {
+    return Predicates.containsPattern("foo");
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/PatternRulesTestOutput.java

@@ -0,0 +1,22 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.base.Predicates;
+import com.google.common.collect.ImmutableSet;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;
+
+final class PatternRulesTest implements RefasterRuleCollectionTestCase {
+  @Override
+  public ImmutableSet<Object> elidedTypesAndStaticImports() {
+    return ImmutableSet.of(Predicates.class);
+  }
+
+  Predicate<?> testPatternAsPredicate() {
+    return Pattern.compile("foo").asPredicate();
+  }
+
+  Predicate<?> testPatternCompileAsPredicate() {
+    return Pattern.compile("foo").asPredicate();
+  }
+}

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestInput.java

@@ -98,7 +98,16 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.just("foo", "bar").zipWith(Flux.just(1, 2), String::repeat);
   }
 
-  Flux<String> testFluxZipWithIterable() {
+  Flux<Tuple2<String, Integer>> testFluxZipWithIterable() {
+    return Flux.zip(Flux.just("foo", "bar"), Flux.fromIterable(ImmutableSet.of(1, 2)));
+  }
+
+  Flux<String> testFluxZipWithIterableBiFunction() {
+    return Flux.just("foo", "bar")
+        .zipWith(Flux.fromIterable(ImmutableSet.of(1, 2)), String::repeat);
+  }
+
+  Flux<String> testFluxZipWithIterableMapFunction() {
     return Flux.just("foo", "bar").zipWithIterable(ImmutableSet.of(1, 2), String::repeat);
   }
 
@@ -118,8 +127,11 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.error(() -> ((Supplier<RuntimeException>) null).get());
   }
 
-  Mono<String> testMonoThenReturn() {
-    return Mono.empty().then(Mono.just("foo"));
+  ImmutableSet<Mono<String>> testMonoThenReturn() {
+    return ImmutableSet.of(
+        Mono.just(1).ignoreElement().thenReturn("foo"),
+        Mono.just(2).then().thenReturn("bar"),
+        Mono.just(3).then(Mono.just("baz")));
   }
 
   Flux<Integer> testFluxTake() {
@@ -136,15 +148,51 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Flux.just("baz").switchIfEmpty(Flux.just("qux")));
   }
 
+  ImmutableSet<Flux<?>> testFluxEmpty() {
+    return ImmutableSet.of(
+        Flux.concat(),
+        Flux.concatDelayError(),
+        Flux.firstWithSignal(),
+        Flux.just(),
+        Flux.merge(),
+        Flux.merge(1),
+        Flux.mergeComparing((a, b) -> 0),
+        Flux.mergeComparing(1, (a, b) -> 0),
+        Flux.mergeComparingDelayError(1, (a, b) -> 0),
+        Flux.mergeDelayError(1),
+        Flux.mergePriority((a, b) -> 0),
+        Flux.mergePriority(1, (a, b) -> 0),
+        Flux.mergePriorityDelayError(1, (a, b) -> 0),
+        Flux.mergeSequential(),
+        Flux.mergeSequential(1),
+        Flux.mergeSequentialDelayError(1),
+        Flux.zip(v -> v),
+        Flux.zip(v -> v, 1),
+        Flux.combineLatest(v -> v),
+        Flux.combineLatest(v -> v, 1),
+        Flux.mergeComparing(),
+        Flux.mergePriority(),
+        Flux.range(0, 0));
+  }
+
+  Flux<Integer> testFluxJust() {
+    return Flux.range(0, 1);
+  }
+
   ImmutableSet<Mono<?>> testMonoIdentity() {
     return ImmutableSet.of(
         Mono.just(1).switchIfEmpty(Mono.empty()),
         Mono.just(2).flux().next(),
         Mono.just(3).flux().singleOrEmpty(),
+        Mono.<Void>empty().ignoreElement(),
         Mono.<Void>empty().then(),
         Mono.<ImmutableList<String>>empty().map(ImmutableList::copyOf));
   }
 
+  Mono<Integer> testMonoSingle() {
+    return Mono.just(1).flux().single();
+  }
+
   ImmutableSet<Flux<Integer>> testFluxSwitchIfEmptyOfEmptyPublisher() {
     return ImmutableSet.of(
         Flux.just(1).switchIfEmpty(Mono.empty()), Flux.just(2).switchIfEmpty(Flux.empty()));
@@ -164,12 +212,26 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Flux.just(3).map(Mono::just).concatMap(identity(), 5));
   }
 
-  Flux<Integer> testFluxConcatMapIterable() {
-    return Flux.just(1, 2).flatMapIterable(ImmutableList::of);
+  ImmutableSet<Flux<Integer>> testMonoFlatMapIterable() {
+    return ImmutableSet.of(
+        Mono.just(1).map(ImmutableSet::of).flatMapIterable(identity()),
+        Mono.just(2).flux().concatMapIterable(ImmutableSet::of));
   }
 
-  Flux<Integer> testFluxConcatMapIterableWithPrefetch() {
-    return Flux.just(1, 2).flatMapIterable(ImmutableList::of, 3);
+  Flux<Integer> testMonoFlatMapIterableIdentity() {
+    return Mono.just(ImmutableSet.of(1)).flatMapMany(Flux::fromIterable);
+  }
+
+  ImmutableSet<Flux<Integer>> testFluxConcatMapIterable() {
+    return ImmutableSet.of(
+        Flux.just(1).flatMapIterable(ImmutableList::of),
+        Flux.just(2).map(ImmutableList::of).concatMapIterable(identity()));
+  }
+
+  ImmutableSet<Flux<Integer>> testFluxConcatMapIterableWithPrefetch() {
+    return ImmutableSet.of(
+        Flux.just(1).flatMapIterable(ImmutableList::of, 3),
+        Flux.just(2).map(ImmutableList::of).concatMapIterable(identity(), 3));
   }
 
   Flux<String> testMonoFlatMapToFlux() {
@@ -247,8 +309,45 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Flux.concat(Mono.just("baz")));
   }
 
-  Mono<Void> testMonoThen() {
-    return Mono.just("foo").flux().then();
+  ImmutableSet<Mono<Void>> testMonoThen() {
+    return ImmutableSet.of(Mono.just("foo").ignoreElement().then(), Mono.just("bar").flux().then());
+  }
+
+  ImmutableSet<Mono<Void>> testFluxThen() {
+    return ImmutableSet.of(
+        Flux.just("foo").ignoreElements().then(), Flux.<Void>empty().ignoreElements());
+  }
+
+  Mono<Void> testMonoThenEmpty() {
+    return Mono.just("foo").ignoreElement().thenEmpty(Mono.empty());
+  }
+
+  Mono<Void> testFluxThenEmpty() {
+    return Flux.just("foo").ignoreElements().thenEmpty(Mono.empty());
+  }
+
+  Flux<String> testMonoThenMany() {
+    return Mono.just("foo").ignoreElement().thenMany(Flux.just("bar"));
+  }
+
+  Flux<String> testMonoThenMonoFlux() {
+    return Mono.just("foo").thenMany(Mono.just("bar"));
+  }
+
+  Flux<String> testFluxThenMany() {
+    return Flux.just("foo").ignoreElements().thenMany(Flux.just("bar"));
+  }
+
+  ImmutableSet<Mono<?>> testMonoThenMono() {
+    return ImmutableSet.of(
+        Mono.just("foo").ignoreElement().then(Mono.just("bar")),
+        Mono.just("baz").thenEmpty(Mono.<Void>empty()));
+  }
+
+  ImmutableSet<Mono<?>> testFluxThenMono() {
+    return ImmutableSet.of(
+        Flux.just("foo").ignoreElements().then(Mono.just("bar")),
+        Flux.just("baz").thenEmpty(Mono.<Void>empty()));
   }
 
   ImmutableSet<Mono<Optional<String>>> testMonoSingleOptional() {
@@ -265,12 +364,33 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.just(1).map(Number.class::cast);
   }
 
+  Mono<Number> testMonoOfType() {
+    return Mono.just(1).filter(Number.class::isInstance).cast(Number.class);
+  }
+
+  Flux<Number> testFluxOfType() {
+    return Flux.just(1).filter(Number.class::isInstance).cast(Number.class);
+  }
+
   Mono<String> testMonoFlatMap() {
     return Mono.just("foo").map(Mono::just).flatMap(identity());
   }
 
-  Flux<String> testMonoFlatMapMany() {
-    return Mono.just("foo").map(Mono::just).flatMapMany(identity());
+  ImmutableSet<Flux<Integer>> testMonoFlatMapMany() {
+    return ImmutableSet.of(
+        Mono.just(1).map(Mono::just).flatMapMany(identity()),
+        Mono.just(2).flux().concatMap(Mono::just),
+        Mono.just(3).flux().concatMap(Mono::just, 2),
+        Mono.just(4).flux().concatMapDelayError(Mono::just),
+        Mono.just(5).flux().concatMapDelayError(Mono::just, 2),
+        Mono.just(6).flux().concatMapDelayError(Mono::just, false, 2),
+        Mono.just(7).flux().flatMap(Mono::just, 2),
+        Mono.just(8).flux().flatMap(Mono::just, 2, 3),
+        Mono.just(9).flux().flatMapDelayError(Mono::just, 2, 3),
+        Mono.just(10).flux().flatMapSequential(Mono::just, 2),
+        Mono.just(11).flux().flatMapSequential(Mono::just, 2, 3),
+        Mono.just(12).flux().flatMapSequentialDelayError(Mono::just, 2, 3),
+        Mono.just(13).flux().switchMap(Mono::just));
   }
 
   ImmutableSet<Flux<String>> testConcatMapIterableIdentity() {
@@ -378,6 +498,10 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.just(1, 4, 3, 2).sort(reverseOrder()).filter(i -> i % 2 == 0);
   }
 
+  Flux<Integer> testFluxTakeWhile() {
+    return Flux.just(1, 2, 3).takeWhile(i -> i % 2 == 0).filter(i -> i % 2 == 0);
+  }
+
   Mono<List<Integer>> testFluxCollectToImmutableList() {
     return Flux.just(1).collectList();
   }
@@ -414,6 +538,13 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         StepVerifier.create(Mono.just("baz")).expectNextMatches("qux"::equals));
   }
 
+  StepVerifier.Step<?> testFluxAsStepVerifierExpectNext() {
+    return Flux.just(1)
+        .collect(toImmutableList())
+        .as(StepVerifier::create)
+        .assertNext(list -> assertThat(list).containsExactly(2));
+  }
+
   Duration testStepVerifierLastStepVerifyComplete() {
     return StepVerifier.create(Mono.empty()).expectComplete().verify();
   }
@@ -426,7 +557,9 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return ImmutableSet.of(
         StepVerifier.create(Mono.empty()).expectError(IllegalArgumentException.class).verify(),
         StepVerifier.create(Mono.empty())
-            .verifyErrorSatisfies(t -> assertThat(t).isInstanceOf(IllegalStateException.class)));
+            .verifyErrorMatches(IllegalStateException.class::isInstance),
+        StepVerifier.create(Mono.empty())
+            .verifyErrorSatisfies(t -> assertThat(t).isInstanceOf(AssertionError.class)));
   }
 
   Duration testStepVerifierLastStepVerifyErrorMatches() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/ReactorRulesTestOutput.java

@@ -102,7 +102,15 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         .map(TupleUtils.function(String::repeat));
   }
 
-  Flux<String> testFluxZipWithIterable() {
+  Flux<Tuple2<String, Integer>> testFluxZipWithIterable() {
+    return Flux.just("foo", "bar").zipWithIterable(ImmutableSet.of(1, 2));
+  }
+
+  Flux<String> testFluxZipWithIterableBiFunction() {
+    return Flux.just("foo", "bar").zipWithIterable(ImmutableSet.of(1, 2), String::repeat);
+  }
+
+  Flux<String> testFluxZipWithIterableMapFunction() {
     return Flux.just("foo", "bar")
         .zipWithIterable(ImmutableSet.of(1, 2))
         .map(function(String::repeat));
@@ -124,8 +132,11 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.error(((Supplier<RuntimeException>) null));
   }
 
-  Mono<String> testMonoThenReturn() {
-    return Mono.empty().thenReturn("foo");
+  ImmutableSet<Mono<String>> testMonoThenReturn() {
+    return ImmutableSet.of(
+        Mono.just(1).thenReturn("foo"),
+        Mono.just(2).thenReturn("bar"),
+        Mono.just(3).thenReturn("baz"));
   }
 
   Flux<Integer> testFluxTake() {
@@ -141,15 +152,51 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Flux.just("foo").defaultIfEmpty("bar"), Flux.just("baz").defaultIfEmpty("qux"));
   }
 
+  ImmutableSet<Flux<?>> testFluxEmpty() {
+    return ImmutableSet.of(
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty(),
+        Flux.empty());
+  }
+
+  Flux<Integer> testFluxJust() {
+    return Flux.just(0);
+  }
+
   ImmutableSet<Mono<?>> testMonoIdentity() {
     return ImmutableSet.of(
         Mono.just(1),
         Mono.just(2),
         Mono.just(3),
         Mono.<Void>empty(),
+        Mono.<Void>empty(),
         Mono.<ImmutableList<String>>empty());
   }
 
+  Mono<Integer> testMonoSingle() {
+    return Mono.just(1).single();
+  }
+
   ImmutableSet<Flux<Integer>> testFluxSwitchIfEmptyOfEmptyPublisher() {
     return ImmutableSet.of(Flux.just(1), Flux.just(2));
   }
@@ -168,12 +215,26 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Flux.just(3).concatMap(Mono::just, 5));
   }
 
-  Flux<Integer> testFluxConcatMapIterable() {
-    return Flux.just(1, 2).concatMapIterable(ImmutableList::of);
+  ImmutableSet<Flux<Integer>> testMonoFlatMapIterable() {
+    return ImmutableSet.of(
+        Mono.just(1).flatMapIterable(ImmutableSet::of),
+        Mono.just(2).flatMapIterable(ImmutableSet::of));
   }
 
-  Flux<Integer> testFluxConcatMapIterableWithPrefetch() {
-    return Flux.just(1, 2).concatMapIterable(ImmutableList::of, 3);
+  Flux<Integer> testMonoFlatMapIterableIdentity() {
+    return Mono.just(ImmutableSet.of(1)).flatMapIterable(identity());
+  }
+
+  ImmutableSet<Flux<Integer>> testFluxConcatMapIterable() {
+    return ImmutableSet.of(
+        Flux.just(1).concatMapIterable(ImmutableList::of),
+        Flux.just(2).concatMapIterable(ImmutableList::of));
+  }
+
+  ImmutableSet<Flux<Integer>> testFluxConcatMapIterableWithPrefetch() {
+    return ImmutableSet.of(
+        Flux.just(1).concatMapIterable(ImmutableList::of, 3),
+        Flux.just(2).concatMapIterable(ImmutableList::of, 3));
   }
 
   Flux<String> testMonoFlatMapToFlux() {
@@ -246,8 +307,42 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         Mono.just("foo").flux(), Mono.just("bar").flux(), Mono.just("baz").flux());
   }
 
-  Mono<Void> testMonoThen() {
-    return Mono.just("foo").then();
+  ImmutableSet<Mono<Void>> testMonoThen() {
+    return ImmutableSet.of(Mono.just("foo").then(), Mono.just("bar").then());
+  }
+
+  ImmutableSet<Mono<Void>> testFluxThen() {
+    return ImmutableSet.of(Flux.just("foo").then(), Flux.<Void>empty().then());
+  }
+
+  Mono<Void> testMonoThenEmpty() {
+    return Mono.just("foo").thenEmpty(Mono.empty());
+  }
+
+  Mono<Void> testFluxThenEmpty() {
+    return Flux.just("foo").thenEmpty(Mono.empty());
+  }
+
+  Flux<String> testMonoThenMany() {
+    return Mono.just("foo").thenMany(Flux.just("bar"));
+  }
+
+  Flux<String> testMonoThenMonoFlux() {
+    return Mono.just("foo").then(Mono.just("bar")).flux();
+  }
+
+  Flux<String> testFluxThenMany() {
+    return Flux.just("foo").thenMany(Flux.just("bar"));
+  }
+
+  ImmutableSet<Mono<?>> testMonoThenMono() {
+    return ImmutableSet.of(
+        Mono.just("foo").then(Mono.just("bar")), Mono.just("baz").then(Mono.<Void>empty()));
+  }
+
+  ImmutableSet<Mono<?>> testFluxThenMono() {
+    return ImmutableSet.of(
+        Flux.just("foo").then(Mono.just("bar")), Flux.just("baz").then(Mono.<Void>empty()));
   }
 
   ImmutableSet<Mono<Optional<String>>> testMonoSingleOptional() {
@@ -262,12 +357,33 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.just(1).cast(Number.class);
   }
 
+  Mono<Number> testMonoOfType() {
+    return Mono.just(1).ofType(Number.class);
+  }
+
+  Flux<Number> testFluxOfType() {
+    return Flux.just(1).ofType(Number.class);
+  }
+
   Mono<String> testMonoFlatMap() {
     return Mono.just("foo").flatMap(Mono::just);
   }
 
-  Flux<String> testMonoFlatMapMany() {
-    return Mono.just("foo").flatMapMany(Mono::just);
+  ImmutableSet<Flux<Integer>> testMonoFlatMapMany() {
+    return ImmutableSet.of(
+        Mono.just(1).flatMapMany(Mono::just),
+        Mono.just(2).flatMapMany(Mono::just),
+        Mono.just(3).flatMapMany(Mono::just),
+        Mono.just(4).flatMapMany(Mono::just),
+        Mono.just(5).flatMapMany(Mono::just),
+        Mono.just(6).flatMapMany(Mono::just),
+        Mono.just(7).flatMapMany(Mono::just),
+        Mono.just(8).flatMapMany(Mono::just),
+        Mono.just(9).flatMapMany(Mono::just),
+        Mono.just(10).flatMapMany(Mono::just),
+        Mono.just(11).flatMapMany(Mono::just),
+        Mono.just(12).flatMapMany(Mono::just),
+        Mono.just(13).flatMapMany(Mono::just));
   }
 
   ImmutableSet<Flux<String>> testConcatMapIterableIdentity() {
@@ -371,6 +487,10 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
     return Flux.just(1, 4, 3, 2).filter(i -> i % 2 == 0).sort(reverseOrder());
   }
 
+  Flux<Integer> testFluxTakeWhile() {
+    return Flux.just(1, 2, 3).takeWhile(i -> i % 2 == 0);
+  }
+
   Mono<List<Integer>> testFluxCollectToImmutableList() {
     return Flux.just(1).collect(toImmutableList());
   }
@@ -405,6 +525,10 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
         StepVerifier.create(Mono.just("baz")).expectNext("qux"));
   }
 
+  StepVerifier.Step<?> testFluxAsStepVerifierExpectNext() {
+    return Flux.just(1).as(StepVerifier::create).expectNext(2);
+  }
+
   Duration testStepVerifierLastStepVerifyComplete() {
     return StepVerifier.create(Mono.empty()).verifyComplete();
   }
@@ -416,7 +540,8 @@ final class ReactorRulesTest implements RefasterRuleCollectionTestCase {
   ImmutableSet<Duration> testStepVerifierLastStepVerifyErrorClass() {
     return ImmutableSet.of(
         StepVerifier.create(Mono.empty()).verifyError(IllegalArgumentException.class),
-        StepVerifier.create(Mono.empty()).verifyError(IllegalStateException.class));
+        StepVerifier.create(Mono.empty()).verifyError(IllegalStateException.class),
+        StepVerifier.create(Mono.empty()).verifyError(AssertionError.class));
   }
 
   Duration testStepVerifierLastStepVerifyErrorMatches() {

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestInput.java

@@ -3,6 +3,7 @@ package tech.picnic.errorprone.refasterrules;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static java.util.Comparator.comparingInt;
 import static java.util.Comparator.reverseOrder;
+import static java.util.function.Function.identity;
 import static java.util.function.Predicate.not;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.filtering;
@@ -19,6 +20,7 @@ import static java.util.stream.Collectors.summingDouble;
 import static java.util.stream.Collectors.summingInt;
 import static java.util.stream.Collectors.summingLong;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Streams;
 import java.util.DoubleSummaryStatistics;
@@ -35,11 +37,13 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<Object> elidedTypesAndStaticImports() {
     return ImmutableSet.of(
+        ImmutableList.class,
         Objects.class,
         Streams.class,
         counting(),
         filtering(null, null),
         flatMapping(null, null),
+        identity(),
         mapping(null, null),
         maxBy(null),
         minBy(null),
@@ -250,4 +254,38 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   ImmutableSet<Integer> testStreamFlatMapCollect() {
     return Stream.of(1).collect(flatMapping(n -> Stream.of(n, n), toImmutableSet()));
   }
+
+  ImmutableSet<Stream<Integer>> testStreamsConcat() {
+    return ImmutableSet.of(
+        Stream.of(Stream.of(1), Stream.of(2)).flatMap(identity()),
+        Stream.of(Stream.of(3), Stream.of(4)).flatMap(v -> v));
+  }
+
+  Stream<Integer> testStreamTakeWhile() {
+    return Stream.of(1, 2, 3).takeWhile(i -> i < 2).filter(i -> i < 2);
+  }
+
+  Stream<Integer> testStreamIterate() {
+    return Stream.iterate(0, i -> i + 1).takeWhile(i -> i < 10);
+  }
+
+  Stream<Integer> testStreamOf1() {
+    return ImmutableList.of(1).stream();
+  }
+
+  Stream<Integer> testStreamOf2() {
+    return ImmutableList.of(1, 2).stream();
+  }
+
+  Stream<Integer> testStreamOf3() {
+    return ImmutableList.of(1, 2, 3).stream();
+  }
+
+  Stream<Integer> testStreamOf4() {
+    return ImmutableList.of(1, 2, 3, 4).stream();
+  }
+
+  Stream<Integer> testStreamOf5() {
+    return ImmutableList.of(1, 2, 3, 4, 5).stream();
+  }
 }

error-prone-contrib/src/test/resources/tech/picnic/errorprone/refasterrules/StreamRulesTestOutput.java

@@ -4,6 +4,7 @@ import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static java.util.Comparator.comparingInt;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Comparator.reverseOrder;
+import static java.util.function.Function.identity;
 import static java.util.function.Predicate.not;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.filtering;
@@ -20,6 +21,7 @@ import static java.util.stream.Collectors.summingDouble;
 import static java.util.stream.Collectors.summingInt;
 import static java.util.stream.Collectors.summingLong;
 
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Streams;
 import java.util.Arrays;
@@ -37,11 +39,13 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   @Override
   public ImmutableSet<Object> elidedTypesAndStaticImports() {
     return ImmutableSet.of(
+        ImmutableList.class,
         Objects.class,
         Streams.class,
         counting(),
         filtering(null, null),
         flatMapping(null, null),
+        identity(),
         mapping(null, null),
         maxBy(null),
         minBy(null),
@@ -251,4 +255,37 @@ final class StreamRulesTest implements RefasterRuleCollectionTestCase {
   ImmutableSet<Integer> testStreamFlatMapCollect() {
     return Stream.of(1).flatMap(n -> Stream.of(n, n)).collect(toImmutableSet());
   }
+
+  ImmutableSet<Stream<Integer>> testStreamsConcat() {
+    return ImmutableSet.of(
+        Streams.concat(Stream.of(1), Stream.of(2)), Streams.concat(Stream.of(3), Stream.of(4)));
+  }
+
+  Stream<Integer> testStreamTakeWhile() {
+    return Stream.of(1, 2, 3).takeWhile(i -> i < 2);
+  }
+
+  Stream<Integer> testStreamIterate() {
+    return Stream.iterate(0, i -> i < 10, i -> i + 1);
+  }
+
+  Stream<Integer> testStreamOf1() {
+    return Stream.of(1);
+  }
+
+  Stream<Integer> testStreamOf2() {
+    return Stream.of(1, 2);
+  }
+
+  Stream<Integer> testStreamOf3() {
+    return Stream.of(1, 2, 3);
+  }
+
+  Stream<Integer> testStreamOf4() {
+    return Stream.of(1, 2, 3, 4);
+  }
+
+  Stream<Integer> testStreamOf5() {
+    return Stream.of(1, 2, 3, 4, 5);
+  }
 }

integration-tests/calcite-calcite-1.35.0-init.patch

@@ -0,0 +1,183 @@
+diff --git a/build.gradle.kts b/build.gradle.kts
+index a9a6c0692..3695e9d9f 100644
+--- a/build.gradle.kts
++++ b/build.gradle.kts
+@@ -91,7 +91,8 @@ fun reportsForHumans() = !(System.getenv()["CI"]?.toBoolean() ?: false)
+ val skipJavadoc by props()
+ val enableMavenLocal by props()
+ val enableGradleMetadata by props()
+-val werror by props(true) // treat javac warnings as errors
++// disable, as error prone will be producing lots of warnings
++val werror by props(false) // treat javac warnings as errors
+ // Inherited from stage-vote-release-plugin: skipSign, useGpgCmd
+ // Inherited from gradle-extensions-plugin: slowSuiteLogThreshold=0L, slowTestLogThreshold=2000L
+ 
+@@ -510,8 +511,8 @@ fun com.github.autostyle.gradle.BaseFormatExtension.license() {
+ 
+     plugins.withType<JavaPlugin> {
+         configure<JavaPluginConvention> {
+-            sourceCompatibility = JavaVersion.VERSION_1_8
+-            targetCompatibility = JavaVersion.VERSION_1_8
++            sourceCompatibility = JavaVersion.VERSION_17
++            targetCompatibility = JavaVersion.VERSION_17
+         }
+         configure<JavaPluginExtension> {
+             consistentResolution {
+@@ -548,6 +549,7 @@ fun com.github.autostyle.gradle.BaseFormatExtension.license() {
+         if (!skipAutostyle) {
+             autostyle {
+                 java {
++                    googleJavaFormat()
+                     filter.exclude(*javaccGeneratedPatterns +
+                             "**/test/java/*.java" +
+                             "**/RelRule.java" /** remove as part of CALCITE-4831 **/)
+@@ -640,7 +642,7 @@ fun com.github.autostyle.gradle.BaseFormatExtension.license() {
+                     replace("hamcrest: nullValue", "org.hamcrest.Matchers.nullValue", "org.hamcrest.CoreMatchers.nullValue")
+                     replace("hamcrest: sameInstance", "org.hamcrest.core.IsSame.sameInstance", "org.hamcrest.CoreMatchers.sameInstance")
+                     replace("hamcrest: startsWith", "org.hamcrest.core.StringStartsWith.startsWith", "org.hamcrest.CoreMatchers.startsWith")
+-                    replaceRegex("hamcrest: size", "\\.size\\(\\), (is|equalTo)\\(", ", hasSize\\(")
++                    // replaceRegex("hamcrest: size", "\\.size\\(\\), (is|equalTo)\\(", ", hasSize\\(")
+                     custom("((() preventer", 1) { contents: String ->
+                         ParenthesisBalancer.apply(contents)
+                     }
+@@ -685,17 +687,26 @@ fun com.github.autostyle.gradle.BaseFormatExtension.license() {
+ 
+         if (enableErrorprone) {
+             apply(plugin = "net.ltgt.errorprone")
++            repositories {
++                mavenLocal()
++            }
++
++            val errorProneFlags = System.getProperty("error-prone.flags")
++            val errorProneSupportVersion = System.getProperty("error-prone-support.version")
++
+             dependencies {
+                 "errorprone"("com.google.errorprone:error_prone_core:${"errorprone".v}")
++                "annotationProcessor"("tech.picnic.error-prone-support:error-prone-contrib:$errorProneSupportVersion")
++                "annotationProcessor"("tech.picnic.error-prone-support:refaster-runner:$errorProneSupportVersion")
+                 "annotationProcessor"("com.google.guava:guava-beta-checker:1.0")
+             }
+             tasks.withType<JavaCompile>().configureEach {
+                 options.errorprone {
++                    allErrorsAsWarnings.set(true)
+                     disableWarningsInGeneratedCode.set(true)
+                     errorproneArgs.add("-XepExcludedPaths:.*/javacc/.*")
+-                    enable(
+-                        "MethodCanBeStatic"
+-                    )
++                    errorproneArgs.addAll(errorProneFlags.toString().split(" "))
++                    errorproneArgs.add("-XepOpt:Refaster:NamePattern=^((?!((JUnitTo)?AssertJ)).*)")
+                     disable(
+                         "ComplexBooleanConstant",
+                         "EqualsGetClass",
+@@ -704,7 +715,12 @@ fun com.github.autostyle.gradle.BaseFormatExtension.license() {
+                         "MutableConstantField",
+                         "ReferenceEquality",
+                         "SameNameButDifferent",
+-                        "TypeParameterUnusedInFormals"
++                        "TypeParameterUnusedInFormals",
++                        "CollectorMutability",
++                        "MethodCanBeStatic",
++                        "StaticImport",
++                        "LexicographicalAnnotationListing",
++                        "LexicographicalAnnotationAttributeListing"
+                     )
+                     // Analyze issues, and enable the check
+                     disable(
+diff --git a/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java b/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java
+index 3cd45f455..1887d0a54 100644
+--- a/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java
++++ b/core/src/main/java/org/apache/calcite/plan/SubstitutionVisitor.java
+@@ -1463,6 +1463,8 @@ private AggregateOnCalcToAggregateUnifyRule() {
+           operand(MutableAggregate.class, target(0)), 1);
+     }
+ 
++
++    @SuppressWarnings("MapEntryComparingByKey")
+     @Override protected @Nullable UnifyResult apply(UnifyRuleCall call) {
+       final MutableAggregate query = (MutableAggregate) call.query;
+       final MutableCalc qInput = (MutableCalc) query.getInput();
+diff --git a/core/src/main/java/org/apache/calcite/plan/volcano/RelSubset.java b/core/src/main/java/org/apache/calcite/plan/volcano/RelSubset.java
+index 29b26adb3..5de5d25cd 100644
+--- a/core/src/main/java/org/apache/calcite/plan/volcano/RelSubset.java
++++ b/core/src/main/java/org/apache/calcite/plan/volcano/RelSubset.java
+@@ -621,6 +621,7 @@ private static String traitDiff(RelTraitSet original, RelTraitSet desired) {
+           .collect(Collectors.joining(", ", "[", "]"));
+     }
+ 
++    @SuppressWarnings("MapEntryComparingByValue")
+     public RelNode visit(
+         RelNode p,
+         int ordinal,
+diff --git a/core/src/main/java/org/apache/calcite/util/ImmutableIntList.java b/core/src/main/java/org/apache/calcite/util/ImmutableIntList.java
+index cb34fe3d5..5dbae21f5 100644
+--- a/core/src/main/java/org/apache/calcite/util/ImmutableIntList.java
++++ b/core/src/main/java/org/apache/calcite/util/ImmutableIntList.java
+@@ -324,10 +324,12 @@ private static class EmptyImmutableIntList extends ImmutableIntList {
+       return a;
+     }
+ 
++    @SuppressWarnings("ImmutableListOf")
+     @Override public Iterator<Integer> iterator() {
+       return Collections.<Integer>emptyList().iterator();
+     }
+ 
++    @SuppressWarnings("ImmutableListOf")
+     @Override public ListIterator<Integer> listIterator() {
+       return Collections.<Integer>emptyList().listIterator();
+     }
+diff --git a/gradle.properties b/gradle.properties
+index 3b0776230..42cfa56f3 100644
+--- a/gradle.properties
++++ b/gradle.properties
+@@ -53,7 +53,7 @@ com.google.protobuf.version=0.8.10
+ de.thetaphi.forbiddenapis.version=3.5.1
+ jacoco.version=0.8.10
+ kotlin.version=1.7.10
+-net.ltgt.errorprone.version=1.3.0
++net.ltgt.errorprone.version=3.1.0
+ me.champeau.gradle.jmh.version=0.5.3
+ org.jetbrains.gradle.plugin.idea-ext.version=0.5
+ org.nosphere.apache.rat.version=0.7.0
+@@ -75,7 +75,7 @@ kotlin.stdlib.default.dependency=false
+ checkerframework.version=3.10.0
+ checkstyle.version=8.28
+ spotbugs.version=3.1.11
+-errorprone.version=2.5.1
++errorprone.version=HEAD-SNAPSHOT
+ # The property is used in https://github.com/wildfly/jandex regression testing, so avoid renaming
+ jandex.version=2.2.3.Final
+ 
+@@ -109,7 +109,7 @@ foodmart-data-hsqldb.version=0.5
+ foodmart-data-json.version=0.4
+ foodmart-queries.version=0.4.1
+ geode-core.version=1.15.1
+-guava.version=19.0
++guava.version=31.1-jre
+ h2.version=2.1.210
+ hadoop.version=2.7.5
+ hamcrest-date.version=2.0.4
+diff --git a/linq4j/src/main/java/org/apache/calcite/linq4j/Linq4j.java b/linq4j/src/main/java/org/apache/calcite/linq4j/Linq4j.java
+index 482a30757..1b22df621 100644
+--- a/linq4j/src/main/java/org/apache/calcite/linq4j/Linq4j.java
++++ b/linq4j/src/main/java/org/apache/calcite/linq4j/Linq4j.java
+@@ -417,6 +417,7 @@ public static <T> boolean equals(T t0, T t1) {
+    * above.
+    */
+   @Deprecated // to be removed before 2.0
++  @SuppressWarnings("RequireNonNullStatement")
+   public static <T> T requireNonNull(T o) {
+     if (o == null) {
+       throw new NullPointerException();
+diff --git a/testkit/src/main/java/org/apache/calcite/sql/parser/SqlParserTest.java b/testkit/src/main/java/org/apache/calcite/sql/parser/SqlParserTest.java
+index d78fab432..449c2ebdd 100644
+--- a/testkit/src/main/java/org/apache/calcite/sql/parser/SqlParserTest.java
++++ b/testkit/src/main/java/org/apache/calcite/sql/parser/SqlParserTest.java
+@@ -98,6 +98,7 @@
+  * @see SqlParserFixture
+  * @see SqlParserListFixture
+  */
++@SuppressWarnings("JUnitClassModifiers")
+ public class SqlParserTest {
+   /**
+    * List of reserved keywords.

integration-tests/checkstyle-checkstyle-10.5.0-init.patch

@@ -0,0 +1,253 @@
+diff --git a/pom.xml b/pom.xml
+index 0f453706b..a478db73f 100644
+--- a/pom.xml
++++ b/pom.xml
+@@ -233,7 +233,8 @@
+     <junit.version>5.9.1</junit.version>
+     <forbiddenapis.version>3.4</forbiddenapis.version>
+     <json-schema-validator.version>1.2.0</json-schema-validator.version>
+-    <error-prone.version>2.15.0</error-prone.version>
++    <error-prone.version>v2.17.0-picnic-3</error-prone.version>
++    <error-prone-support.version>0.7.0</error-prone-support.version>
+     <checkerframework.version>3.27.0</checkerframework.version>
+   </properties>
+ 
+@@ -333,6 +334,12 @@
+       <version>1.1.3</version>
+       <scope>test</scope>
+     </dependency>
++    <dependency>
++      <groupId>org.assertj</groupId>
++      <artifactId>assertj-core</artifactId>
++      <version>3.24.1</version>
++      <scope>test</scope>
++    </dependency>
+     <dependency>
+       <groupId>nl.jqno.equalsverifier</groupId>
+       <artifactId>equalsverifier</artifactId>
+@@ -2322,15 +2329,25 @@
+                     <arg>-Xpkginfo:always</arg>
+                     <arg>-XDcompilePolicy=simple</arg>
+                     <arg>
+-                      -Xplugin:ErrorProne
++                      -Xplugin:ErrorProne ${error-prone.flags}
+                     </arg>
+                   </compilerArgs>
+                   <annotationProcessorPaths>
+                     <path>
+-                      <groupId>com.google.errorprone</groupId>
++                      <groupId>com.github.PicnicSupermarket.error-prone</groupId>
+                       <artifactId>error_prone_core</artifactId>
+                       <version>${error-prone.version}</version>
+                     </path>
++                    <path>
++                      <groupId>tech.picnic.error-prone-support</groupId>
++                      <artifactId>error-prone-contrib</artifactId>
++                      <version>${error-prone-support.version}</version>
++                    </path>
++                    <path>
++                      <groupId>tech.picnic.error-prone-support</groupId>
++                      <artifactId>refaster-runner</artifactId>
++                      <version>${error-prone-support.version}</version>
++                    </path>
+                   </annotationProcessorPaths>
+                 </configuration>
+               </execution>
+@@ -2375,15 +2392,26 @@
+                     <arg>-XDcompilePolicy=simple</arg>
+                     <arg>
+                       -Xplugin:ErrorProne \
+-                      -XepExcludedPaths:.*[\\/]resources[\\/].*
++                      -XepExcludedPaths:.*[\\/]resources[\\/].* \
++                      ${error-prone.flags}
+                     </arg>
+                   </compilerArgs>
+                   <annotationProcessorPaths>
+                     <path>
+-                      <groupId>com.google.errorprone</groupId>
++                      <groupId>com.github.PicnicSupermarket.error-prone</groupId>
+                       <artifactId>error_prone_core</artifactId>
+                       <version>${error-prone.version}</version>
+                     </path>
++                    <path>
++                      <groupId>tech.picnic.error-prone-support</groupId>
++                      <artifactId>error-prone-contrib</artifactId>
++                      <version>${error-prone-support.version}</version>
++                    </path>
++                    <path>
++                      <groupId>tech.picnic.error-prone-support</groupId>
++                      <artifactId>refaster-runner</artifactId>
++                      <version>${error-prone-support.version}</version>
++                    </path>
+                   </annotationProcessorPaths>
+                 </configuration>
+               </execution>
+diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/DetailNodeTreeStringPrinter.java b/src/main/java/com/puppycrawl/tools/checkstyle/DetailNodeTreeStringPrinter.java
+index de390a42c..a0ff7a866 100644
+--- a/src/main/java/com/puppycrawl/tools/checkstyle/DetailNodeTreeStringPrinter.java
++++ b/src/main/java/com/puppycrawl/tools/checkstyle/DetailNodeTreeStringPrinter.java
+@@ -63,6 +63,7 @@ public final class DetailNodeTreeStringPrinter {
+      * @return DetailNode tree
+      * @throws IllegalArgumentException if there is an error parsing the Javadoc.
+      */
++    @SuppressWarnings("CheckArgumentWithMessage")
+     public static DetailNode parseJavadocAsDetailNode(DetailAST blockComment) {
+         final JavadocDetailNodeParser parser = new JavadocDetailNodeParser();
+         final ParseStatus status = parser.parseJavadocAsDetailNode(blockComment);
+diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java b/src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java
+index bec9669bf..2ad0f4467 100644
+--- a/src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java
++++ b/src/main/java/com/puppycrawl/tools/checkstyle/PackageObjectFactory.java
+@@ -300,6 +300,7 @@ public class PackageObjectFactory implements ModuleFactory {
+      * @return the map of third party Checkstyle module names to the set of their fully qualified
+      *      names
+      */
++    @SuppressWarnings("CollectorMutability")
+     private Map<String, Set<String>> generateThirdPartyNameToFullModuleName(ClassLoader loader) {
+         Map<String, Set<String>> returnValue;
+         try {
+diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/SarifLogger.java b/src/main/java/com/puppycrawl/tools/checkstyle/SarifLogger.java
+index 399893f40..aa93aca80 100644
+--- a/src/main/java/com/puppycrawl/tools/checkstyle/SarifLogger.java
++++ b/src/main/java/com/puppycrawl/tools/checkstyle/SarifLogger.java
+@@ -140,6 +140,7 @@ public class SarifLogger extends AutomaticBean implements AuditListener {
+     @Override
+     public void auditFinished(AuditEvent event) {
+         final String version = SarifLogger.class.getPackage().getImplementationVersion();
++        @SuppressWarnings("IdentityConversion")
+         final String rendered = report
+             .replace(VERSION_PLACEHOLDER, String.valueOf(version))
+             .replace(RESULTS_PLACEHOLDER, String.join(",\n", results));
+diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheck.java b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheck.java
+index fd1d9d729..d5d891d6e 100644
+--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheck.java
++++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalCatchCheck.java
+@@ -152,6 +152,7 @@ public final class IllegalCatchCheck extends AbstractCheck {
+     public static final String MSG_KEY = "illegal.catch";
+ 
+     /** Specify exception class names to reject. */
++    @SuppressWarnings("CollectorMutability")
+     private final Set<String> illegalClassNames = Arrays.stream(new String[] {"Exception", "Error",
+         "RuntimeException", "Throwable", "java.lang.Error", "java.lang.Exception",
+         "java.lang.RuntimeException", "java.lang.Throwable", }).collect(Collectors.toSet());
+diff --git a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheck.java b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheck.java
+index d00cd2fdf..4a0d9220d 100644
+--- a/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheck.java
++++ b/src/main/java/com/puppycrawl/tools/checkstyle/checks/coding/IllegalThrowsCheck.java
+@@ -159,10 +159,12 @@ public final class IllegalThrowsCheck extends AbstractCheck {
+     public static final String MSG_KEY = "illegal.throw";
+ 
+     /** Specify names of methods to ignore. */
++    @SuppressWarnings("CollectorMutability")
+     private final Set<String> ignoredMethodNames =
+         Arrays.stream(new String[] {"finalize", }).collect(Collectors.toSet());
+ 
+     /** Specify throw class names to reject. */
++    @SuppressWarnings("CollectorMutability")
+     private final Set<String> illegalClassNames = Arrays.stream(
+         new String[] {"Error", "RuntimeException", "Throwable", "java.lang.Error",
+                       "java.lang.RuntimeException", "java.lang.Throwable", })
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/AbstractModuleTestSupport.java b/src/test/java/com/puppycrawl/tools/checkstyle/AbstractModuleTestSupport.java
+index 157e65406..239c2ecc6 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/AbstractModuleTestSupport.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/AbstractModuleTestSupport.java
+@@ -553,6 +553,7 @@ public abstract class AbstractModuleTestSupport extends AbstractPathTestSupport
+      */
+     protected static String[] removeSuppressed(String[] actualViolations,
+                                                String... suppressedViolations) {
++        @SuppressWarnings("CollectorMutability")
+         final List<String> actualViolationsList =
+             Arrays.stream(actualViolations).collect(Collectors.toList());
+         actualViolationsList.removeAll(Arrays.asList(suppressedViolations));
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/CheckerTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/CheckerTest.java
+index 8fee6bfed..7e20a1580 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/CheckerTest.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/CheckerTest.java
+@@ -90,6 +90,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
+  * @noinspectionreason ClassWithTooManyDependencies - complex tests require a large number
+  *      of imports
+  */
++@SuppressWarnings("JUnitClassModifiers")
+ public class CheckerTest extends AbstractModuleTestSupport {
+ 
+     @TempDir
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/ConfigurationLoaderTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/ConfigurationLoaderTest.java
+index 72881222e..9e81ede00 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/ConfigurationLoaderTest.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/ConfigurationLoaderTest.java
+@@ -46,6 +46,7 @@ import com.puppycrawl.tools.checkstyle.internal.utils.TestUtil;
+ /**
+  * Unit test for ConfigurationLoader.
+  */
++@SuppressWarnings("JUnitClassModifiers")
+ public class ConfigurationLoaderTest extends AbstractPathTestSupport {
+ 
+     @Override
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/JavaAstVisitorTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/JavaAstVisitorTest.java
+index 5280ab216..2b984fe89 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/JavaAstVisitorTest.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/JavaAstVisitorTest.java
+@@ -106,6 +106,7 @@ public class JavaAstVisitorTest extends AbstractModuleTestSupport {
+                 .map(Method::getName)
+                 .collect(Collectors.toSet());
+ 
++        @SuppressWarnings("CollectorMutability")
+         final Set<String> filteredVisitMethodNames = Arrays.stream(visitMethods)
+                 .filter(method -> method.getName().contains("visit"))
+                 .filter(method -> method.getModifiers() == Modifier.PUBLIC)
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/PackageObjectFactoryTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/PackageObjectFactoryTest.java
+index 41636ec4b..9ada7757d 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/PackageObjectFactoryTest.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/PackageObjectFactoryTest.java
+@@ -98,6 +98,7 @@ public class PackageObjectFactoryTest {
+     public void testCtorNullPackageException1() {
+         final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+         try {
++            @SuppressWarnings("ImmutableSetOf1")
+             final Object test = new PackageObjectFactory(Collections.singleton(null), classLoader);
+             assertWithMessage("Exception is expected but got " + test).fail();
+         }
+@@ -126,6 +127,7 @@ public class PackageObjectFactoryTest {
+     public void testCtorNullPackageException3() {
+         final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
+         try {
++            @SuppressWarnings("ImmutableSetOf1")
+             final Object test = new PackageObjectFactory(Collections.singleton(null), classLoader,
+                     TRY_IN_ALL_REGISTERED_PACKAGES);
+             assertWithMessage("Exception is expected but got " + test).fail();
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/TreeWalkerTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/TreeWalkerTest.java
+index da5d8f2af..4b6f85e95 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/TreeWalkerTest.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/TreeWalkerTest.java
+@@ -79,6 +79,7 @@ import com.puppycrawl.tools.checkstyle.utils.CommonUtil;
+  * @noinspectionreason ClassWithTooManyDependencies - complex tests require a
+  *      large number of imports
+  */
++@SuppressWarnings("JUnitClassModifiers")
+ public class TreeWalkerTest extends AbstractModuleTestSupport {
+ 
+     @TempDir
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/internal/XpathRegressionTest.java b/src/test/java/com/puppycrawl/tools/checkstyle/internal/XpathRegressionTest.java
+index 2e5ce578c..ebf661993 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/XpathRegressionTest.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/XpathRegressionTest.java
+@@ -180,6 +180,7 @@ public class XpathRegressionTest extends AbstractModuleTestSupport {
+     @Test
+     public void validateIncompatibleJavadocCheckNames() throws IOException {
+         // subclasses of AbstractJavadocCheck
++        @SuppressWarnings("CollectorMutability")
+         final Set<Class<?>> abstractJavadocCheckNames = CheckUtil.getCheckstyleChecks()
+                 .stream()
+                 .filter(AbstractJavadocCheck.class::isAssignableFrom)
+diff --git a/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/CheckUtil.java b/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/CheckUtil.java
+index ae779e07b..55f68955e 100644
+--- a/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/CheckUtil.java
++++ b/src/test/java/com/puppycrawl/tools/checkstyle/internal/utils/CheckUtil.java
+@@ -78,6 +78,7 @@ public final class CheckUtil {
+      * @param checks class instances.
+      * @return a set of simple names.
+      */
++    @SuppressWarnings("CollectorMutability")
+     public static Set<String> getSimpleNames(Set<Class<?>> checks) {
+         return checks.stream().map(check -> {
+             String name = check.getSimpleName();