[maven-release-plugin] prepare release v0.12.0

Summary of key changes:
- The `MissingRefasterAnnotation` check was contributed to Error Prone,
  and so is deleted here (multiple checks with the same name are not
  supported).
- Similarly, Error Prone now supports the `-XepAllSuggestionsAsWarnings`
  flag out of the box. So the `ErrorProneFork` class is deleted, as it
  has currently no further use.

While there, include a tweak to `run-mutation-tests.sh`.

Fixes #686.

See:
- https://github.com/google/error-prone/releases/tag/v2.20.0
- https://github.com/google/error-prone/compare/v2.19.1...v2.20.0
- https://github.com/PicnicSupermarket/error-prone/compare/v2.19.1-picnic-1...v2.20.0-picnic-1

.github/workflows/build.yaml

@@ -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@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@5ffc13f4174014e2d4d4572b3d74c3fa61aeb2c2 # v3.11.0
         with:
           java-version: ${{ matrix.jdk }}
           distribution: ${{ matrix.distribution }}

.github/workflows/codeql.yml

@@ -22,11 +22,11 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@5ffc13f4174014e2d4d4572b3d74c3fa61aeb2c2 # v3.11.0
         with:
           java-version: 17.0.7
           distribution: temurin

.github/workflows/deploy-website.yaml

@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           persist-credentials: false
       - uses: ruby/setup-ruby@v1.126.0
@@ -20,7 +20,7 @@ jobs:
           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@66b63f4a7de003f4f00cc8e9af4b83b8f2abdb96 # v1.0.9
         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@ee48c7b82e077d7b8ef30b50a719e6a792a50c9a # v2.0.2

.github/workflows/openssf-scorecard.yml

@@ -21,7 +21,7 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           persist-credentials: false
       - name: Run OpenSSF Scorecard analysis

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

@@ -12,12 +12,12 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           fetch-depth: 2
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@5ffc13f4174014e2d4d4572b3d74c3fa61aeb2c2 # v3.11.0
         with:
           java-version: 17.0.7
           distribution: temurin
@@ -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@0b7f8abb1508181956e8e162db84b466c27e18ce # v3.1.2
         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@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@5ffc13f4174014e2d4d4572b3d74c3fa61aeb2c2 # v3.11.0
         with:
           java-version: 17.0.7
           distribution: temurin
           cache: maven
       - name: Download Pitest analysis artifact
-        uses: dawidd6/action-download-artifact@v2.24.2
+        uses: dawidd6/action-download-artifact@246dbf436b23d7c49e21a7ab8204ca9ecd1fe615 # v2.27.0
         with:
           workflow: ${{ github.event.workflow_run.workflow_id }}
           name: pitest-reports

.github/workflows/sonarcloud.yml

@@ -16,12 +16,12 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@c85c95e3d7251135ab7dc9ce3241c5835cc595a9 # v3.5.3
         with:
           fetch-depth: 0
           persist-credentials: false
       - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+        uses: actions/setup-java@5ffc13f4174014e2d4d4572b3d74c3fa61aeb2c2 # v3.11.0
         with:
           java-version: 17.0.7
           distribution: temurin

.renovaterc.json

@@ -1,5 +1,8 @@
 {
   "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": [
+    "helpers:pinGitHubActionDigests"
+  ],
   "packageRules": [
     {
       "matchPackagePatterns": [

documentation-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.11.1</version>
+        <version>0.12.0</version>
     </parent>
 
     <artifactId>documentation-support</artifactId>

error-prone-contrib/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.11.1</version>
+        <version>0.12.0</version>
     </parent>
 
     <artifactId>error-prone-contrib</artifactId>

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/refasterrules/CollectionRules.java

@@ -164,6 +164,8 @@ 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/OptionalRules.java

@@ -8,6 +8,7 @@ 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;
@@ -19,6 +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
@@ -118,7 +120,7 @@ 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);
@@ -138,7 +140,7 @@ 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);
@@ -161,6 +163,7 @@ 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));
     }
@@ -224,6 +227,28 @@ 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.
@@ -325,6 +350,9 @@ 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 and third 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),

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/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/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/resources/tech/picnic/errorprone/refasterrules/OptionalRulesTestInput.java

@@ -119,4 +119,11 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
   Optional<String> testOptionalMap() {
     return Optional.of(1).stream().map(String::valueOf).findAny();
   }
+
+  ImmutableSet<String> testOptionalOrElseGet() {
+    return ImmutableSet.of(
+        Optional.of("foo").orElse("bar"),
+        Optional.of("baz").orElse(toString()),
+        Optional.of("qux").orElse(String.valueOf(true)));
+  }
 }

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

@@ -112,4 +112,11 @@ final class OptionalRulesTest implements RefasterRuleCollectionTestCase {
   Optional<String> testOptionalMap() {
     return Optional.of(1).map(String::valueOf);
   }
+
+  ImmutableSet<String> testOptionalOrElseGet() {
+    return ImmutableSet.of(
+        Optional.of("foo").orElse("bar"),
+        Optional.of("baz").orElse(toString()),
+        Optional.of("qux").orElseGet(() -> String.valueOf(true)));
+  }
 }

pom.xml

@@ -4,7 +4,7 @@
 
     <groupId>tech.picnic.error-prone-support</groupId>
     <artifactId>error-prone-support</artifactId>
-    <version>0.11.1</version>
+    <version>0.12.0</version>
     <packaging>pom</packaging>
 
     <name>Picnic :: Error Prone Support</name>
@@ -49,7 +49,7 @@
 
     <scm>
         <developerConnection>scm:git:git@github.com:PicnicSupermarket/error-prone-support.git</developerConnection>
-        <tag>v0.11.1</tag>
+        <tag>v0.12.0</tag>
         <url>https://github.com/PicnicSupermarket/error-prone-support</url>
     </scm>
     <issueManagement>
@@ -141,7 +141,7 @@
         <groupId.error-prone>com.google.errorprone</groupId.error-prone>
         <!-- The build timestamp is derived from the most recent commit
         timestamp in support of reproducible builds. -->
-        <project.build.outputTimestamp>2023-05-16T15:37:41Z</project.build.outputTimestamp>
+        <project.build.outputTimestamp>2023-06-21T19:08:33Z</project.build.outputTimestamp>
         <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
         <!-- Glob pattern identifying Refaster rule definition files. These
         Java classes don't contain "regular" code, and thus require special
@@ -197,11 +197,11 @@
         <!-- Dependency and plugin versions that are referenced in more than
         one place. We use these to keep dependencies in sync. Version numbers
         that need to be referenced only once should *not* be listed here. -->
-        <version.auto-service>1.0.1</version.auto-service>
+        <version.auto-service>1.1.1</version.auto-service>
         <version.auto-value>1.10.1</version.auto-value>
         <version.error-prone>${version.error-prone-orig}</version.error-prone>
         <version.error-prone-fork>v${version.error-prone-orig}-picnic-1</version.error-prone-fork>
-        <version.error-prone-orig>2.19.1</version.error-prone-orig>
+        <version.error-prone-orig>2.20.0</version.error-prone-orig>
         <version.error-prone-slf4j>0.1.18</version.error-prone-slf4j>
         <version.guava-beta-checker>1.0</version.guava-beta-checker>
         <version.jdk>11</version.jdk>
@@ -209,8 +209,8 @@
         <version.mockito>5.3.1</version.mockito>
         <version.nopen-checker>1.0.1</version.nopen-checker>
         <version.nullaway>0.10.10</version.nullaway>
-        <version.pitest-git>1.0.10</version.pitest-git>
-        <version.surefire>3.1.0</version.surefire>
+        <version.pitest-git>1.0.11</version.pitest-git>
+        <version.surefire>3.1.2</version.surefire>
     </properties>
 
     <dependencyManagement>
@@ -268,7 +268,7 @@
             <dependency>
                 <groupId>com.fasterxml.jackson</groupId>
                 <artifactId>jackson-bom</artifactId>
-                <version>2.15.0</version>
+                <version>2.15.2</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
@@ -307,14 +307,14 @@
             <dependency>
                 <groupId>com.google.guava</groupId>
                 <artifactId>guava-bom</artifactId>
-                <version>31.1-jre</version>
+                <version>32.0.1-jre</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
             <dependency>
                 <groupId>com.google.truth</groupId>
                 <artifactId>truth</artifactId>
-                <version>1.1.3</version>
+                <version>1.1.4</version>
             </dependency>
             <!-- Specified as a workaround for
             https://github.com/mojohaus/versions-maven-plugin/issues/244. -->
@@ -326,7 +326,7 @@
             <dependency>
                 <groupId>com.newrelic.agent.java</groupId>
                 <artifactId>newrelic-api</artifactId>
-                <version>8.2.0</version>
+                <version>8.3.0</version>
             </dependency>
             <!-- Specified as a workaround for
             https://github.com/mojohaus/versions-maven-plugin/issues/244. -->
@@ -338,7 +338,7 @@
             <dependency>
                 <groupId>io.projectreactor</groupId>
                 <artifactId>reactor-bom</artifactId>
-                <version>2022.0.7</version>
+                <version>2022.0.8</version>
                 <type>pom</type>
                 <scope>import</scope>
             </dependency>
@@ -350,12 +350,12 @@
             <dependency>
                 <groupId>io.swagger</groupId>
                 <artifactId>swagger-annotations</artifactId>
-                <version>1.6.10</version>
+                <version>1.6.11</version>
             </dependency>
             <dependency>
                 <groupId>io.swagger.core.v3</groupId>
                 <artifactId>swagger-annotations</artifactId>
-                <version>2.2.9</version>
+                <version>2.2.12</version>
             </dependency>
             <dependency>
                 <groupId>jakarta.servlet</groupId>
@@ -387,7 +387,7 @@
             <dependency>
                 <groupId>net.bytebuddy</groupId>
                 <artifactId>byte-buddy</artifactId>
-                <version>1.14.4</version>
+                <version>1.14.5</version>
             </dependency>
             <!-- Specified so that Renovate will file Maven upgrade PRs, which
             subsequently will cause `maven-enforcer-plugin` to require that
@@ -412,7 +412,7 @@
             <dependency>
                 <groupId>org.checkerframework</groupId>
                 <artifactId>checker-qual</artifactId>
-                <version>3.34.0</version>
+                <version>3.35.0</version>
             </dependency>
             <dependency>
                 <groupId>org.hamcrest</groupId>
@@ -458,12 +458,12 @@
             <dependency>
                 <groupId>org.springframework.boot</groupId>
                 <artifactId>spring-boot-test</artifactId>
-                <version>2.7.11</version>
+                <version>2.7.12</version>
             </dependency>
             <dependency>
                 <groupId>org.testng</groupId>
                 <artifactId>testng</artifactId>
-                <version>7.7.1</version>
+                <version>7.8.0</version>
             </dependency>
         </dependencies>
     </dependencyManagement>
@@ -570,7 +570,7 @@
                 <plugin>
                     <groupId>io.github.git-commit-id</groupId>
                     <artifactId>git-commit-id-maven-plugin</artifactId>
-                    <version>5.0.0</version>
+                    <version>6.0.0</version>
                     <configuration>
                         <injectAllReactorProjects>true</injectAllReactorProjects>
                         <runOnlyOnce>true</runOnlyOnce>
@@ -589,7 +589,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-checkstyle-plugin</artifactId>
-                    <version>3.2.2</version>
+                    <version>3.3.0</version>
                     <configuration>
                         <checkstyleRules>
                             <!-- We only enable rules that are not enforced by
@@ -839,7 +839,7 @@
                         <dependency>
                             <groupId>com.puppycrawl.tools</groupId>
                             <artifactId>checkstyle</artifactId>
-                            <version>10.11.0</version>
+                            <version>10.12.0</version>
                         </dependency>
                         <dependency>
                             <groupId>io.spring.nohttp</groupId>
@@ -940,7 +940,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-dependency-plugin</artifactId>
-                    <version>3.5.0</version>
+                    <version>3.6.0</version>
                     <configuration>
                         <!-- XXX: Drop `ignoreAllNonTestScoped` once
                         https://issues.apache.org/jira/browse/MNG-6058 is
@@ -972,7 +972,7 @@
                             <banDuplicateClasses>
                                 <dependencies>
                                     <dependency>
-                                        <groupId>org.checkerframework</groupId>
+                                        <groupId>io.github.eisop</groupId>
                                         <artifactId>dataflow-errorprone</artifactId>
                                         <!-- This package is contained in
                                         Checker Framework's `checker-qual` and
@@ -1051,7 +1051,7 @@
                         <dependency>
                             <groupId>org.codehaus.mojo</groupId>
                             <artifactId>extra-enforcer-rules</artifactId>
-                            <version>1.6.2</version>
+                            <version>1.7.0</version>
                         </dependency>
                     </dependencies>
                     <executions>
@@ -1141,7 +1141,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-release-plugin</artifactId>
-                    <version>3.0.0</version>
+                    <version>3.0.1</version>
                     <configuration>
                         <autoVersionSubmodules>true</autoVersionSubmodules>
                         <preparationProfiles>release</preparationProfiles>
@@ -1168,7 +1168,7 @@
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-source-plugin</artifactId>
-                    <version>3.2.1</version>
+                    <version>3.3.0</version>
                     <executions>
                         <execution>
                             <id>generate-source-jar</id>
@@ -1202,7 +1202,7 @@
                 <plugin>
                     <groupId>org.codehaus.mojo</groupId>
                     <artifactId>license-maven-plugin</artifactId>
-                    <version>2.0.1</version>
+                    <version>2.1.0</version>
                     <configuration>
                         <includedLicenses>
                             <!-- The SPDX IDs of licenses of third-party
@@ -1305,7 +1305,7 @@
                 <plugin>
                     <groupId>org.codehaus.mojo</groupId>
                     <artifactId>versions-maven-plugin</artifactId>
-                    <version>2.15.0</version>
+                    <version>2.16.0</version>
                     <configuration>
                         <updateBuildOutputTimestampPolicy>never</updateBuildOutputTimestampPolicy>
                     </configuration>
@@ -1356,7 +1356,7 @@
                 <plugin>
                     <groupId>org.pitest</groupId>
                     <artifactId>pitest-maven</artifactId>
-                    <version>1.13.1</version>
+                    <version>1.14.1</version>
                     <configuration>
                         <excludedClasses>
                             <!-- AutoValue generated classes. -->
@@ -1385,7 +1385,7 @@
                         <dependency>
                             <groupId>com.groupcdg.arcmutate</groupId>
                             <artifactId>base</artifactId>
-                            <version>1.0.4</version>
+                            <version>1.0.5</version>
                         </dependency>
                         <dependency>
                             <groupId>com.groupcdg.pitest</groupId>
@@ -1395,7 +1395,7 @@
                         <dependency>
                             <groupId>org.pitest</groupId>
                             <artifactId>pitest-junit5-plugin</artifactId>
-                            <version>1.1.2</version>
+                            <version>1.2.0</version>
                         </dependency>
                     </dependencies>
                     <executions>
@@ -1720,6 +1720,9 @@
                                     -Xep:Java7ApiChecker:OFF
                                     <!-- We don't target JDK 8. -->
                                     -Xep:Java8ApiChecker:OFF
+                                    <!-- XXX: Triggers an IOOBE. See
+                                    https://github.com/google/error-prone/pull/3976. -->
+                                    -Xep:MemberName:OFF
                                     <!-- We don't target Android. -->
                                     -Xep:StaticOrDefaultInterfaceMethod:OFF
                                     <!-- We generally discourage `var` use. -->

refaster-compiler/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.11.1</version>
+        <version>0.12.0</version>
     </parent>
 
     <artifactId>refaster-compiler</artifactId>

refaster-runner/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.11.1</version>
+        <version>0.12.0</version>
     </parent>
 
     <artifactId>refaster-runner</artifactId>
@@ -45,6 +45,7 @@
         <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>refaster-support</artifactId>
+            <scope>runtime</scope>
         </dependency>
         <dependency>
             <groupId>com.google.auto.service</groupId>

refaster-runner/src/test/java/tech/picnic/errorprone/refaster/runner/RefasterTest.java

@@ -22,7 +22,6 @@ import org.junit.jupiter.api.Test;
 import org.junit.jupiter.params.ParameterizedTest;
 import org.junit.jupiter.params.provider.Arguments;
 import org.junit.jupiter.params.provider.MethodSource;
-import tech.picnic.errorprone.refaster.ErrorProneFork;
 
 final class RefasterTest {
   private final CompilationTestHelper compilationHelper =
@@ -80,74 +79,66 @@ final class RefasterTest {
     SeverityLevel defaultSeverity = BugCheckerInfo.create(Refaster.class).defaultSeverity();
 
     /* { arguments, expectedSeverities } */
-    return Stream.concat(
-        Stream.of(
-            arguments(
-                ImmutableList.of(), ImmutableList.of(defaultSeverity, WARNING, ERROR, SUGGESTION)),
-            arguments(ImmutableList.of("-Xep:Refaster:OFF"), ImmutableList.of()),
-            arguments(
-                ImmutableList.of("-Xep:Refaster:DEFAULT"),
-                ImmutableList.of(defaultSeverity, WARNING, ERROR, SUGGESTION)),
-            arguments(
-                ImmutableList.of("-Xep:Refaster:WARN"),
-                ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
-            arguments(
-                ImmutableList.of("-Xep:Refaster:ERROR"),
-                ImmutableList.of(ERROR, ERROR, ERROR, ERROR)),
-            arguments(
-                ImmutableList.of("-XepAllErrorsAsWarnings"),
-                ImmutableList.of(defaultSeverity, WARNING, WARNING, SUGGESTION)),
-            arguments(
-                ImmutableList.of("-Xep:Refaster:OFF", "-XepAllErrorsAsWarnings"),
-                ImmutableList.of()),
-            arguments(
-                ImmutableList.of("-Xep:Refaster:DEFAULT", "-XepAllErrorsAsWarnings"),
-                ImmutableList.of(defaultSeverity, WARNING, WARNING, SUGGESTION)),
-            arguments(
-                ImmutableList.of("-Xep:Refaster:WARN", "-XepAllErrorsAsWarnings"),
-                ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
-            arguments(
-                ImmutableList.of("-Xep:Refaster:ERROR", "-XepAllErrorsAsWarnings"),
-                ImmutableList.of(WARNING, WARNING, WARNING, WARNING))),
-        ErrorProneFork.isErrorProneForkAvailable()
-            ? Stream.of(
-                arguments(
-                    ImmutableList.of("-Xep:Refaster:OFF", "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of()),
-                arguments(
-                    ImmutableList.of("-Xep:Refaster:DEFAULT", "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of(WARNING, WARNING, ERROR, WARNING)),
-                arguments(
-                    ImmutableList.of("-Xep:Refaster:WARN", "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
-                arguments(
-                    ImmutableList.of("-Xep:Refaster:ERROR", "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of(ERROR, ERROR, ERROR, ERROR)),
-                arguments(
-                    ImmutableList.of(
-                        "-Xep:Refaster:OFF",
-                        "-XepAllErrorsAsWarnings",
-                        "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of()),
-                arguments(
-                    ImmutableList.of(
-                        "-Xep:Refaster:DEFAULT",
-                        "-XepAllErrorsAsWarnings",
-                        "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
-                arguments(
-                    ImmutableList.of(
-                        "-Xep:Refaster:WARN",
-                        "-XepAllErrorsAsWarnings",
-                        "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
-                arguments(
-                    ImmutableList.of(
-                        "-Xep:Refaster:ERROR",
-                        "-XepAllErrorsAsWarnings",
-                        "-XepAllSuggestionsAsWarnings"),
-                    ImmutableList.of(WARNING, WARNING, WARNING, WARNING)))
-            : Stream.empty());
+    return Stream.of(
+        arguments(
+            ImmutableList.of(), ImmutableList.of(defaultSeverity, WARNING, ERROR, SUGGESTION)),
+        arguments(ImmutableList.of("-Xep:Refaster:OFF"), ImmutableList.of()),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:DEFAULT"),
+            ImmutableList.of(defaultSeverity, WARNING, ERROR, SUGGESTION)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:WARN"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:ERROR"), ImmutableList.of(ERROR, ERROR, ERROR, ERROR)),
+        arguments(
+            ImmutableList.of("-XepAllErrorsAsWarnings"),
+            ImmutableList.of(defaultSeverity, WARNING, WARNING, SUGGESTION)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:OFF", "-XepAllErrorsAsWarnings"), ImmutableList.of()),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:DEFAULT", "-XepAllErrorsAsWarnings"),
+            ImmutableList.of(defaultSeverity, WARNING, WARNING, SUGGESTION)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:WARN", "-XepAllErrorsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:ERROR", "-XepAllErrorsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
+        arguments(
+            ImmutableList.of("-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, ERROR, WARNING)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:OFF", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of()),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:DEFAULT", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, ERROR, WARNING)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:WARN", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
+        arguments(
+            ImmutableList.of("-Xep:Refaster:ERROR", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(ERROR, ERROR, ERROR, ERROR)),
+        arguments(
+            ImmutableList.of("-XepAllErrorsAsWarnings", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
+        arguments(
+            ImmutableList.of(
+                "-Xep:Refaster:OFF", "-XepAllErrorsAsWarnings", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of()),
+        arguments(
+            ImmutableList.of(
+                "-Xep:Refaster:DEFAULT", "-XepAllErrorsAsWarnings", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
+        arguments(
+            ImmutableList.of(
+                "-Xep:Refaster:WARN", "-XepAllErrorsAsWarnings", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)),
+        arguments(
+            ImmutableList.of(
+                "-Xep:Refaster:ERROR", "-XepAllErrorsAsWarnings", "-XepAllSuggestionsAsWarnings"),
+            ImmutableList.of(WARNING, WARNING, WARNING, WARNING)));
   }
 
   /**

refaster-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.11.1</version>
+        <version>0.12.0</version>
     </parent>
 
     <artifactId>refaster-support</artifactId>

refaster-support/src/main/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformer.java

@@ -148,8 +148,7 @@ public abstract class AnnotatedCompositeCodeTransformer implements CodeTransform
 
   private static SeverityLevel overrideSeverity(SeverityLevel severity, Context context) {
     ErrorProneOptions options = context.get(ErrorProneOptions.class);
-    SeverityLevel minSeverity =
-        ErrorProneFork.isSuggestionsAsWarningsEnabled(options) ? WARNING : SUGGESTION;
+    SeverityLevel minSeverity = options.isSuggestionsAsWarnings() ? WARNING : SUGGESTION;
     SeverityLevel maxSeverity = options.isDropErrorsToWarnings() ? WARNING : ERROR;
 
     return Comparators.max(Comparators.min(severity, minSeverity), maxSeverity);

refaster-support/src/main/java/tech/picnic/errorprone/refaster/ErrorProneFork.java

@@ -1,56 +0,0 @@
-package tech.picnic.errorprone.refaster;
-
-import com.google.errorprone.ErrorProneOptions;
-import java.lang.reflect.InvocationTargetException;
-import java.lang.reflect.Method;
-import java.lang.reflect.Modifier;
-import java.util.Arrays;
-import java.util.Optional;
-
-/**
- * Utility class that enables the runtime to determine whether Picnic's fork of Error Prone is on
- * the classpath.
- *
- * @see <a href="https://github.com/PicnicSupermarket/error-prone">Picnic's Error Prone fork</a>
- */
-public final class ErrorProneFork {
-  private static final Optional<Method> ERROR_PRONE_OPTIONS_IS_SUGGESTIONS_AS_WARNINGS_METHOD =
-      Arrays.stream(ErrorProneOptions.class.getDeclaredMethods())
-          .filter(m -> Modifier.isPublic(m.getModifiers()))
-          .filter(m -> "isSuggestionsAsWarnings".equals(m.getName()))
-          .findFirst();
-
-  private ErrorProneFork() {}
-
-  /**
-   * Tells whether Picnic's fork of Error Prone is available.
-   *
-   * @return {@code true} iff classpath introspection indicates the presence of Error Prone
-   *     modifications that are assumed to be present only in Picnic's fork.
-   */
-  public static boolean isErrorProneForkAvailable() {
-    return ERROR_PRONE_OPTIONS_IS_SUGGESTIONS_AS_WARNINGS_METHOD.isPresent();
-  }
-
-  /**
-   * Tells whether the custom {@code -XepAllSuggestionsAsWarnings} flag is set.
-   *
-   * @param options The currently active Error Prone options.
-   * @return {@code true} iff {@link #isErrorProneForkAvailable() the Error Prone fork is available}
-   *     and the aforementioned flag is set.
-   * @see <a href="https://github.com/google/error-prone/pull/3301">google/error-prone#3301</a>
-   */
-  public static boolean isSuggestionsAsWarningsEnabled(ErrorProneOptions options) {
-    return ERROR_PRONE_OPTIONS_IS_SUGGESTIONS_AS_WARNINGS_METHOD
-        .filter(m -> Boolean.TRUE.equals(invoke(m, options)))
-        .isPresent();
-  }
-
-  private static Object invoke(Method method, Object obj, Object... args) {
-    try {
-      return method.invoke(obj, args);
-    } catch (IllegalAccessException | InvocationTargetException e) {
-      throw new IllegalStateException(String.format("Failed to invoke method '%s'", method), e);
-    }
-  }
-}

refaster-support/src/main/java/tech/picnic/errorprone/refaster/matchers/IsLikelyTrivialComputation.java

@@ -0,0 +1,92 @@
+package tech.picnic.errorprone.refaster.matchers;
+
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.ArrayAccessTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.IdentifierTree;
+import com.sun.source.tree.LambdaExpressionTree;
+import com.sun.source.tree.LiteralTree;
+import com.sun.source.tree.MemberReferenceTree;
+import com.sun.source.tree.MemberSelectTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.ParenthesizedTree;
+import com.sun.source.tree.TypeCastTree;
+import com.sun.source.tree.UnaryTree;
+
+/** A matcher of expressions that likely require little to no computation. */
+public final class IsLikelyTrivialComputation implements Matcher<ExpressionTree> {
+  private static final long serialVersionUID = 1L;
+
+  /** Instantiates a new {@link IsLikelyTrivialComputation} instance. */
+  public IsLikelyTrivialComputation() {}
+
+  @Override
+  public boolean matches(ExpressionTree expressionTree, VisitorState state) {
+    if (expressionTree instanceof MethodInvocationTree) {
+      // XXX: Method invocations are generally *not* trivial computations, but we make an exception
+      // for nullary method invocations on the result of a trivial computation. This exception
+      // allows this `Matcher` to by the `OptionalOrElseGet` Refaster rule, such that it does not
+      // suggest the introduction of lambda expressions that are better expressed as method
+      // references. Once the `MethodReferenceUsage` bug checker is production-ready, this exception
+      // should be removed. (But at that point, instead defining a `RequiresComputation` matcher may
+      // be more appropriate.)
+      MethodInvocationTree methodInvocation = (MethodInvocationTree) expressionTree;
+      if (methodInvocation.getArguments().isEmpty()
+          && matches(methodInvocation.getMethodSelect())) {
+        return true;
+      }
+    }
+
+    return matches(expressionTree);
+  }
+
+  // XXX: Some `BinaryTree`s may represent what could be considered "trivial computations".
+  // Depending on feedback such trees may be matched in the future.
+  private static boolean matches(ExpressionTree expressionTree) {
+    if (expressionTree instanceof ArrayAccessTree) {
+      return matches(((ArrayAccessTree) expressionTree).getExpression())
+          && matches(((ArrayAccessTree) expressionTree).getIndex());
+    }
+
+    if (expressionTree instanceof LiteralTree) {
+      return true;
+    }
+
+    if (expressionTree instanceof LambdaExpressionTree) {
+      /*
+       * Lambda expressions encapsulate computations, but their definition does not involve
+       * significant computation.
+       */
+      return true;
+    }
+
+    if (expressionTree instanceof IdentifierTree) {
+      return true;
+    }
+
+    if (expressionTree instanceof MemberReferenceTree) {
+      return matches(((MemberReferenceTree) expressionTree).getQualifierExpression());
+    }
+
+    if (expressionTree instanceof MemberSelectTree) {
+      return matches(((MemberSelectTree) expressionTree).getExpression());
+    }
+
+    if (expressionTree instanceof ParenthesizedTree) {
+      return matches(((ParenthesizedTree) expressionTree).getExpression());
+    }
+
+    if (expressionTree instanceof TypeCastTree) {
+      return matches(((TypeCastTree) expressionTree).getExpression());
+    }
+
+    if (expressionTree instanceof UnaryTree) {
+      // XXX: Arguably side-effectful options such as pre- and post-increment and -decrement are not
+      // trivial.
+      return matches(((UnaryTree) expressionTree).getExpression());
+    }
+
+    return false;
+  }
+}

refaster-support/src/test/java/tech/picnic/errorprone/refaster/ErrorProneForkTest.java

@@ -1,67 +0,0 @@
-package tech.picnic.errorprone.refaster;
-
-import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.junit.jupiter.api.Assumptions.assumeTrue;
-
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.CompilationTestHelper;
-import com.google.errorprone.ErrorProneOptions;
-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.sun.source.tree.ClassTree;
-import org.junit.jupiter.api.Test;
-
-final class ErrorProneForkTest {
-  @Test
-  void isErrorProneForkAvailable() {
-    assertThat(ErrorProneFork.isErrorProneForkAvailable())
-        .isEqualTo(Boolean.TRUE.toString().equals(System.getProperty("error-prone-fork-in-use")));
-  }
-
-  @Test
-  void isSuggestionsAsWarningsEnabledWithoutFlag() {
-    CompilationTestHelper.newInstance(TestChecker.class, getClass())
-        .addSourceLines(
-            "A.java",
-            "// BUG: Diagnostic contains: Suggestions as warnings enabled: false",
-            "class A {}")
-        .doTest();
-  }
-
-  @Test
-  void isSuggestionsAsWarningsEnabledWithFlag() {
-    assumeTrue(
-        ErrorProneFork.isErrorProneForkAvailable(),
-        "Picnic's Error Prone fork is not on the classpath");
-
-    CompilationTestHelper.newInstance(TestChecker.class, getClass())
-        .setArgs("-XepAllSuggestionsAsWarnings")
-        .addSourceLines(
-            "A.java",
-            "// BUG: Diagnostic contains: Suggestions as warnings enabled: true",
-            "class A {}")
-        .doTest();
-  }
-
-  /**
-   * A {@link BugChecker} that reports the result of {@link
-   * ErrorProneFork#isSuggestionsAsWarningsEnabled(ErrorProneOptions)}.
-   */
-  @BugPattern(summary = "Flags classes with a custom error message", severity = ERROR)
-  public static final class TestChecker extends BugChecker implements ClassTreeMatcher {
-    private static final long serialVersionUID = 1L;
-
-    @Override
-    public Description matchClass(ClassTree tree, VisitorState state) {
-      return buildDescription(tree)
-          .setMessage(
-              String.format(
-                  "Suggestions as warnings enabled: %s",
-                  ErrorProneFork.isSuggestionsAsWarningsEnabled(state.errorProneOptions())))
-          .build();
-    }
-  }
-}

refaster-support/src/test/java/tech/picnic/errorprone/refaster/matchers/AbstractMatcherTestChecker.java

@@ -8,8 +8,11 @@ import com.google.errorprone.matchers.Matcher;
 import com.sun.source.tree.CompilationUnitTree;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.ImportTree;
+import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.Tree;
+import com.sun.source.tree.TypeCastTree;
+import com.sun.source.util.TreePath;
 import com.sun.source.util.TreeScanner;
 import org.jspecify.annotations.Nullable;
 
@@ -31,18 +34,27 @@ abstract class AbstractMatcherTestChecker extends BugChecker implements Compilat
 
   @Override
   public Description matchCompilationUnit(CompilationUnitTree compilationUnit, VisitorState state) {
-    new TreeScanner<@Nullable Void, @Nullable Void>() {
+    new TreeScanner<@Nullable Void, TreePath>() {
       @Override
-      public @Nullable Void scan(Tree tree, @Nullable Void unused) {
-        if (tree instanceof ExpressionTree && delegate.matches((ExpressionTree) tree, state)) {
-          state.reportMatch(describeMatch(tree));
+      public @Nullable Void scan(@Nullable Tree tree, TreePath treePath) {
+        if (tree == null) {
+          return null;
         }
 
-        return super.scan(tree, unused);
+        TreePath path = new TreePath(treePath, tree);
+        if (tree instanceof ExpressionTree) {
+          ExpressionTree expressionTree = (ExpressionTree) tree;
+          if (!isMethodSelect(expressionTree, path)
+              && delegate.matches(expressionTree, state.withPath(path))) {
+            state.reportMatch(describeMatch(tree));
+          }
+        }
+
+        return super.scan(tree, path);
       }
 
       @Override
-      public @Nullable Void visitImport(ImportTree node, @Nullable Void unused) {
+      public @Nullable Void visitImport(ImportTree tree, TreePath path) {
         /*
          * We're not interested in matching import statements. While components of these
          * can be `ExpressionTree`s, they will never be matched by Refaster.
@@ -51,15 +63,42 @@ abstract class AbstractMatcherTestChecker extends BugChecker implements Compilat
       }
 
       @Override
-      public @Nullable Void visitMethod(MethodTree node, @Nullable Void unused) {
+      public @Nullable Void visitMethod(MethodTree tree, TreePath path) {
         /*
          * We're not interested in matching e.g. parameter and return type declarations. While these
          * can be `ExpressionTree`s, they will never be matched by Refaster.
          */
-        return scan(node.getBody(), unused);
+        return scan(tree.getBody(), new TreePath(path, tree));
       }
-    }.scan(compilationUnit, null);
+
+      @Override
+      public @Nullable Void visitTypeCast(TypeCastTree tree, TreePath path) {
+        /*
+         * We're not interested in matching the parenthesized type subtree that is part of a type
+         * cast expression. While such trees can be `ExpressionTree`s, they will never be matched by
+         * Refaster.
+         */
+        return scan(tree.getExpression(), new TreePath(path, tree));
+      }
+    }.scan(compilationUnit, state.getPath());
 
     return Description.NO_MATCH;
   }
+
+  /**
+   * Tells whether the given {@link ExpressionTree} is the {@link
+   * MethodInvocationTree#getMethodSelect() method select} portion of a method invocation.
+   *
+   * <p>Such {@link ExpressionTree}s will never be matched by Refaster.
+   */
+  private static boolean isMethodSelect(ExpressionTree tree, TreePath path) {
+    TreePath parentPath = path.getParentPath();
+    if (parentPath == null) {
+      return false;
+    }
+
+    Tree parentTree = parentPath.getLeaf();
+    return parentTree instanceof MethodInvocationTree
+        && ((MethodInvocationTree) parentTree).getMethodSelect().equals(tree);
+  }
 }

refaster-support/src/test/java/tech/picnic/errorprone/refaster/matchers/IsLikelyTrivialComputationTest.java

@@ -0,0 +1,147 @@
+package tech.picnic.errorprone.refaster.matchers;
+
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.CompilationTestHelper;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.sun.source.tree.ReturnTree;
+import org.junit.jupiter.api.Test;
+
+final class IsLikelyTrivialComputationTest {
+  @Test
+  void matches() {
+    CompilationTestHelper.newInstance(MatcherTestChecker.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import java.util.function.Predicate;",
+            "",
+            "class A {",
+            "  String negative1() {",
+            "    return String.valueOf(1);",
+            "  }",
+            "",
+            "  String negative2() {",
+            "    return toString().toString();",
+            "  }",
+            "",
+            "  String negative3() {",
+            "    return \"foo\" + toString();",
+            "  }",
+            "",
+            "  byte negative4() {",
+            "    return \"foo\".getBytes()[0];",
+            "  }",
+            "",
+            "  int negative5() {",
+            "    int[] arr = new int[0];",
+            "    return arr[hashCode()];",
+            "  }",
+            "",
+            "  int negative6() {",
+            "    return 1 * 2;",
+            "  }",
+            "",
+            "  Predicate<String> negative7() {",
+            "    return toString()::equals;",
+            "  }",
+            "",
+            "  String negative8() {",
+            "    return (toString());",
+            "  }",
+            "",
+            "  Object negative9() {",
+            "    return (Object) toString();",
+            "  }",
+            "",
+            "  int negative10() {",
+            "    return -hashCode();",
+            "  }",
+            "",
+            "  String positive1() {",
+            "    // BUG: Diagnostic contains:",
+            "    return toString();",
+            "  }",
+            "",
+            "  String positive2() {",
+            "    // BUG: Diagnostic contains:",
+            "    return this.toString();",
+            "  }",
+            "",
+            "  int positive3() {",
+            "    int[] arr = new int[0];",
+            "    // BUG: Diagnostic contains:",
+            "    return arr[0];",
+            "  }",
+            "",
+            "  String positive4() {",
+            "    // BUG: Diagnostic contains:",
+            "    return null;",
+            "  }",
+            "",
+            "  boolean positive5() {",
+            "    // BUG: Diagnostic contains:",
+            "    return false;",
+            "  }",
+            "",
+            "  int positive6() {",
+            "    // BUG: Diagnostic contains:",
+            "    return 0;",
+            "  }",
+            "",
+            "  String positive7() {",
+            "    // BUG: Diagnostic contains:",
+            "    return \"foo\" + \"bar\";",
+            "  }",
+            "",
+            "  Predicate<String> positive8() {",
+            "    // BUG: Diagnostic contains:",
+            "    return v -> \"foo\".equals(v);",
+            "  }",
+            "",
+            "  A positive9() {",
+            "    // BUG: Diagnostic contains:",
+            "    return this;",
+            "  }",
+            "",
+            "  Predicate<String> positive10() {",
+            "    // BUG: Diagnostic contains:",
+            "    return \"foo\"::equals;",
+            "  }",
+            "",
+            "  A positive11() {",
+            "    // BUG: Diagnostic contains:",
+            "    return (this);",
+            "  }",
+            "",
+            "  Object positive12() {",
+            "    // BUG: Diagnostic contains:",
+            "    return (Object) this;",
+            "  }",
+            "",
+            "  boolean positive13() {",
+            "    // BUG: Diagnostic contains:",
+            "    return !false;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  /** A {@link BugChecker} that simply delegates to {@link IsLikelyTrivialComputation}. */
+  @BugPattern(
+      summary = "Flags return statement expressions matched by `IsLikelyTrivialComputation`",
+      severity = ERROR)
+  public static final class MatcherTestChecker extends AbstractMatcherTestChecker {
+    private static final long serialVersionUID = 1L;
+
+    // XXX: This is a false positive reported by Checkstyle. See
+    // https://github.com/checkstyle/checkstyle/issues/10161#issuecomment-1242732120.
+    @SuppressWarnings("RedundantModifier")
+    public MatcherTestChecker() {
+      super(
+          (expressionTree, state) ->
+              state.getPath().getParentPath().getLeaf() instanceof ReturnTree
+                  && new IsLikelyTrivialComputation().matches(expressionTree, state));
+    }
+  }
+}

refaster-test-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.11.1</version>
+        <version>0.12.0</version>
     </parent>
 
     <artifactId>refaster-test-support</artifactId>

run-mutation-tests.sh

@@ -1,8 +1,8 @@
 #!/usr/bin/env bash
 
-# Executes Pitest to determine the code base' mutation test coverage. The set
-# of tests executed can optionally be restricted by name. The results are found
-# in each Maven module's `target/pit-reports` directory.
+# Executes Pitest to determine the code's mutation test coverage. The set of
+# tests executed can optionally be restricted by name. The results are found in
+# each Maven module's `target/pit-reports` directory.
 
 set -e -u -o pipefail
 
@@ -11,7 +11,7 @@ if [ "${#}" -gt 1 ]; then
   exit 1
 fi
 
-targetTests=${1:-*}
+targetTests="${1:-*}"
 
 mvn clean test pitest:mutationCoverage \
   -DargLine.xmx=2048m \