WIP: Matching fails, not sure why

See:
- https://github.com/hcoles/pitest/releases/tag/1.15.7
- https://github.com/hcoles/pitest/compare/1.15.6...1.15.7

.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.yml

@@ -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, 21.0.0 ]
         distribution: [ temurin ]
         experimental: [ false ]
         include:
-          - os: macos-12
-            jdk: 17.0.7
+          - os: macos-14
+            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 }}
@@ -30,16 +30,12 @@ jobs:
       # on Maven Central, and once against the Picnic Error Prone fork,
       # additionally enabling all checks defined in this project and any Error
       # Prone checks available only from other artifact repositories.
-      - name: Check out code
-        uses: actions/checkout@v3.1.0
-        with:
-          persist-credentials: false
-      - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+      - name: Check out code and set up JDK and Maven
+        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
         with:
           java-version: ${{ matrix.jdk }}
-          distribution: ${{ matrix.distribution }}
-          cache: maven
+          java-distribution: ${{ matrix.distribution }}
+          maven-version: 3.9.6
       - name: Display build environment details
         run: mvn --version
       - name: Build project against vanilla Error Prone, compile Javadoc

.github/workflows/codeql.yml

@@ -21,24 +21,20 @@ jobs:
       security-events: write
     runs-on: ubuntu-22.04
     steps:
-      - name: Check out code
-        uses: actions/checkout@v3.1.0
+      - name: Check out code and set up JDK and Maven
+        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
         with:
-          persist-credentials: false
-      - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
-        with:
-          java-version: 17.0.7
-          distribution: temurin
-          cache: maven
+          java-version: 17.0.8
+          java-distribution: temurin
+          maven-version: 3.9.6
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@v2.2.11
+        uses: github/codeql-action/init@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
         with:
           languages: ${{ matrix.language }}
       - name: Perform minimal build
         if: matrix.language == 'java'
-        run: mvn -T1C clean install -DskipTests -Dverification.skip
+        run: mvn -T1C clean package -DskipTests -Dverification.skip
       - name: Perform CodeQL analysis
-        uses: github/codeql-action/analyze@v2.2.11
+        uses: github/codeql-action/analyze@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
         with:
           category: /language:${{ matrix.language }}

.github/workflows/deploy-website.yml

@@ -12,15 +12,15 @@ jobs:
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
         with:
           persist-credentials: false
-      - uses: ruby/setup-ruby@v1.126.0
+      - uses: ruby/setup-ruby@bd03e04863f52d169e18a2b190e8fa6b84938215 # v1.170.0
         with:
           working-directory: ./website
           bundler-cache: true
       - name: Configure Github Pages
-        uses: actions/configure-pages@v2.1.3
+        uses: actions/configure-pages@1f0c5cde4bc74cd7e1254d0cb4de8d49e9068c7d # v4.0.0
       - 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@56afc609e74202658d3ffba0e8f6dda462b719fa # v3.0.1
         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@decdde0ac072f6dcbe43649d82d9c635fff5b4e4 # v4.0.4

.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@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
         with:
           persist-credentials: false
       - name: Run OpenSSF Scorecard analysis
-        uses: ossf/scorecard-action@v2.1.3
+        uses: ossf/scorecard-action@0864cf19026789058feabb7e87baa5f140aac736 # v2.3.1
         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@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
         with:
           sarif_file: results.sarif

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

@@ -11,17 +11,13 @@ jobs:
   analyze-pr:
     runs-on: ubuntu-22.04
     steps:
-      - name: Check out code
-        uses: actions/checkout@v3.1.0
+      - name: Check out code and set up JDK and Maven
+        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
         with:
-          fetch-depth: 2
-          persist-credentials: false
-      - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
-        with:
-          java-version: 17.0.7
-          distribution: temurin
-          cache: maven
+          checkout-fetch-depth: 2
+          java-version: 17.0.8
+          java-distribution: temurin
+          maven-version: 3.9.6
       - name: Run Pitest
         # By running with features `+GIT(from[HEAD~1]), +gitci`, Pitest only
         # analyzes lines changed in the associated pull request, as GitHub
@@ -32,7 +28,7 @@ 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@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4.3.1
         with:
           name: pitest-reports
           path: ./target/pit-reports-ci

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

@@ -19,18 +19,14 @@ jobs:
       pull-requests: write
     runs-on: ubuntu-22.04
     steps:
-      - name: Check out code
-        uses: actions/checkout@v3.1.0
+      - name: Check out code and set up JDK and Maven
+        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
         with:
-          persist-credentials: false
-      - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
-        with:
-          java-version: 17.0.7
-          distribution: temurin
-          cache: maven
+          java-version: 17.0.8
+          java-distribution: temurin
+          maven-version: 3.9.6
       - name: Download Pitest analysis artifact
-        uses: dawidd6/action-download-artifact@v2.24.2
+        uses: dawidd6/action-download-artifact@e7466d1a7587ed14867642c2ca74b5bcc1e19a2d # v3.0.0
         with:
           workflow: ${{ github.event.workflow_run.workflow_id }}
           name: pitest-reports

.github/workflows/run-integration-tests.yml

@@ -0,0 +1,39 @@
+# If requested by means of a pull request comment, runs integration tests
+# against the project, using the code found on the pull request branch.
+# XXX: Generalize this to a matrix build of multiple integration tests,
+# possibly using multiple JDK or OS versions.
+# XXX: Investigate whether the comment can specify which integration tests run
+# run. See this example of a dynamic build matrix:
+# https://docs.github.com/en/actions/learn-github-actions/expressions#example-returning-a-json-object
+name: "Integration tests"
+on:
+  issue_comment:
+    types: [ created ]
+permissions:
+  contents: read
+jobs:
+  run-integration-tests:
+    name: On-demand integration test
+    if: |
+      github.event.issue.pull_request && contains(github.event.comment.body, '/integration-test')
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Check out code and set up JDK and Maven
+        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+        with:
+          checkout-ref: "refs/pull/${{ github.event.issue.number }}/head"
+          java-version: 17.0.8
+          java-distribution: temurin
+          maven-version: 3.9.6
+      - name: Install project to local Maven repository
+        run: mvn -T1C install -DskipTests -Dverification.skip
+      - name: Run integration test
+        run: xvfb-run ./integration-tests/checkstyle.sh "${{ runner.temp }}/artifacts"
+      - name: Upload artifacts on failure
+        if: ${{ failure() }}
+        uses: actions/upload-artifact@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4.3.1
+        with:
+          name: integration-test-checkstyle
+          path: "${{ runner.temp }}/artifacts"
+      - name: Remove installed project artifacts
+        run: mvn build-helper:remove-project-artifact

.github/workflows/sonarcloud.yml

@@ -11,21 +11,20 @@ permissions:
   contents: read
 jobs:
   analyze:
+    # Analysis of code in forked repositories is skipped, as such workflow runs
+    # do not have access to the requisite secrets.
+    if: github.event.pull_request.head.repo.full_name == github.repository
     permissions:
       contents: read
     runs-on: ubuntu-22.04
     steps:
-      - name: Check out code
-        uses: actions/checkout@v3.1.0
+      - name: Check out code and set up JDK and Maven
+        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
         with:
-          fetch-depth: 0
-          persist-credentials: false
-      - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
-        with:
-          java-version: 17.0.7
-          distribution: temurin
-          cache: maven
+          checkout-fetch-depth: 0
+          java-version: 17.0.8
+          java-distribution: temurin
+          maven-version: 3.9.6
       - name: Create missing `test` directory
         # XXX: Drop this step in favour of actually having a test.
         run: mkdir refaster-compiler/src/test

.gitignore

@@ -9,3 +9,6 @@
 target
 *.iml
 *.swp
+
+# The Git repositories checked out by the integration test framework.
+integration-tests/.repos

.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

LICENSE.md

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2017-2023 Picnic Technologies BV
+Copyright (c) 2017-2024 Picnic Technologies BV
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -15,9 +15,11 @@ focussing on maintainability, consistency and avoidance of common pitfalls.
 > Error Prone is a static analysis tool for Java that catches common
 > programming mistakes at compile-time.
 
-Read more on how Picnic uses Error Prone (Support) in the blog post [_Picnic
-loves Error Prone: producing high-quality and consistent Java
-code_][picnic-blog-ep-post].
+To learn more about Error Prone (Support), how you can start using Error Prone
+in practice, and how we use it at Picnic, watch the conference talk
+[_Automating away bugs with Error Prone in practice_][conference-talk]. Also
+consider checking out the blog post [_Picnic loves Error Prone: producing
+high-quality and consistent Java code_][picnic-blog-ep-post].
 
 [![Maven Central][maven-central-badge]][maven-central-search]
 [![Reproducible Builds][reproducible-builds-badge]][reproducible-builds-report]
@@ -63,6 +65,8 @@ it, read the installation guide for Maven or Gradle below.
                <plugin>
                    <groupId>org.apache.maven.plugins</groupId>
                    <artifactId>maven-compiler-plugin</artifactId>
+                   <!-- Prefer using the latest release. -->
+                   <version>3.12.0</version>
                    <configuration>
                        <annotationProcessorPaths>
                            <!-- Error Prone itself. -->
@@ -92,8 +96,6 @@ it, read the installation guide for Maven or Gradle below.
                            </arg>
                            <arg>-XDcompilePolicy=simple</arg>
                        </compilerArgs>
-                       <!-- Some checks raise warnings rather than errors. -->
-                       <showWarnings>true</showWarnings>
                        <!-- Enable this if you'd like to fail your build upon warnings. -->
                        <!-- <failOnWarning>true</failOnWarning> -->
                    </configuration>
@@ -223,10 +225,13 @@ 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:
@@ -262,6 +267,7 @@ channel; please see our [security policy][security] for details.
 [bug-checks-identity-conversion]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/IdentityConversion.java
 [codeql-badge]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/codeql.yml/badge.svg?branch=master&event=push
 [codeql-master]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/codeql.yml?query=branch:master+event:push
+[conference-talk]: https://www.youtube.com/watch?v=-47WD-3wKBs
 [contributing]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/CONTRIBUTING.md
 [contributing-pull-request]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/CONTRIBUTING.md#-opening-a-pull-request
 [error-prone-bugchecker]: https://github.com/google/error-prone/blob/master/check_api/src/main/java/com/google/errorprone/bugpatterns/BugChecker.java
@@ -271,8 +277,8 @@ channel; please see our [security policy][security] for details.
 [error-prone-installation-guide]: https://errorprone.info/docs/installation#maven
 [error-prone-orig-repo]: https://github.com/google/error-prone
 [error-prone-pull-3301]: https://github.com/google/error-prone/pull/3301
-[github-actions-build-badge]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/build.yaml/badge.svg
-[github-actions-build-master]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/build.yaml?query=branch:master&event=push
+[github-actions-build-badge]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/build.yml/badge.svg
+[github-actions-build-master]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/build.yml?query=branch:master&event=push
 [google-java-format]: https://github.com/google/google-java-format
 [idea-288052]: https://youtrack.jetbrains.com/issue/IDEA-288052
 [license-badge]: https://img.shields.io/github/license/PicnicSupermarket/error-prone-support
@@ -283,7 +289,7 @@ 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 +302,7 @@ 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

cdg-pitest-licence.txt

@@ -1,7 +1,7 @@
 # Arcmutate license for Error Prone Support, requested by sending an email to
 # support@arcmutate.com.
-expires=07/11/2023
+expires=27/10/2025
 keyVersion=1
-signature=MhZxMbnO6UovNfllM0JuVWkZyvRT3/G5o/uT0Mm36c7200VpZNVu03gTAGivnl9W5RzvZhfpIHccuQ5ctjQkrqhsFSrl4fyqPqu3y5V2fsHIdFXP/G72EGj6Kay9ndLpaEHalqE0bEwxdnHMzEYq5y3O9vUPv8MhUl57xk+rvBo\=
+signature=aQLVt0J//7nXDAlJuBe9ru7Dq6oApcLh17rxsgHoJqBkUCd2zvrtRxkcPm5PmF1I8gBDT9PHb+kTf6Kcfz+D1fT0wRrZv38ip56521AQPD6zjRSqak9O2Gisjo+QTPMD7oS009aSWKzQ1SMdtuZ+KIRvw4Gl+frtYzexqnGWEUQ\=
 packages=tech.picnic.errorprone.*
 type=OSSS

documentation-support/pom.xml

@@ -5,13 +5,14 @@
     <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>
 
     <name>Picnic :: Error Prone Support :: Documentation Support</name>
     <description>Data extraction support for the purpose of documentation generation.</description>
+    <url>https://error-prone.picnic.tech</url>
 
     <dependencies>
         <dependency>
@@ -40,6 +41,14 @@
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-databind</artifactId>
         </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.datatype</groupId>
+            <artifactId>jackson-datatype-guava</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.module</groupId>
+            <artifactId>jackson-module-parameter-names</artifactId>
+        </dependency>
         <dependency>
             <groupId>com.google.auto</groupId>
             <artifactId>auto-common</artifactId>
@@ -73,6 +82,8 @@
             <artifactId>junit-jupiter-api</artifactId>
             <scope>test</scope>
         </dependency>
+        <!-- XXX: Explicitly declared as a workaround for
+        https://github.com/pitest/pitest-junit5-plugin/issues/105. -->
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-engine</artifactId>

documentation-support/src/main/java/tech/picnic/errorprone/documentation/BugPatternExtractor.java

@@ -4,18 +4,22 @@ import static com.google.common.base.Verify.verify;
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static java.util.Objects.requireNonNull;
 
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
 import com.google.auto.common.AnnotationMirrors;
+import com.google.auto.service.AutoService;
 import com.google.auto.value.AutoValue;
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.BugPattern.SeverityLevel;
+import com.google.errorprone.VisitorState;
 import com.google.errorprone.annotations.Immutable;
 import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.AnnotationTree;
 import com.sun.source.tree.ClassTree;
 import com.sun.tools.javac.code.Attribute;
 import com.sun.tools.javac.code.Symbol.ClassSymbol;
-import com.sun.tools.javac.util.Context;
+import java.net.URI;
+import java.util.Optional;
 import javax.lang.model.element.AnnotationValue;
 import tech.picnic.errorprone.documentation.BugPatternExtractor.BugPatternDocumentation;
 
@@ -23,29 +27,40 @@ import tech.picnic.errorprone.documentation.BugPatternExtractor.BugPatternDocume
  * An {@link Extractor} that describes how to extract data from a {@code @BugPattern} annotation.
  */
 @Immutable
-final class BugPatternExtractor implements Extractor<BugPatternDocumentation> {
-  @Override
-  public BugPatternDocumentation extract(ClassTree tree, Context context) {
-    ClassSymbol symbol = ASTHelpers.getSymbol(tree);
-    BugPattern annotation = symbol.getAnnotation(BugPattern.class);
-    requireNonNull(annotation, "BugPattern annotation must be present");
+@AutoService(Extractor.class)
+@SuppressWarnings("rawtypes" /* See https://github.com/google/auto/issues/870. */)
+public final class BugPatternExtractor implements Extractor<BugPatternDocumentation> {
+  /** Instantiates a new {@link BugPatternExtractor} instance. */
+  public BugPatternExtractor() {}
 
-    return new AutoValue_BugPatternExtractor_BugPatternDocumentation(
-        symbol.getQualifiedName().toString(),
-        annotation.name().isEmpty() ? tree.getSimpleName().toString() : annotation.name(),
-        ImmutableList.copyOf(annotation.altNames()),
-        annotation.link(),
-        ImmutableList.copyOf(annotation.tags()),
-        annotation.summary(),
-        annotation.explanation(),
-        annotation.severity(),
-        annotation.disableable(),
-        annotation.documentSuppression() ? getSuppressionAnnotations(tree) : ImmutableList.of());
+  @Override
+  public String identifier() {
+    return "bugpattern";
   }
 
   @Override
-  public boolean canExtract(ClassTree tree) {
-    return ASTHelpers.hasDirectAnnotationWithSimpleName(tree, BugPattern.class.getSimpleName());
+  public Optional<BugPatternDocumentation> tryExtract(ClassTree tree, VisitorState state) {
+    ClassSymbol symbol = ASTHelpers.getSymbol(tree);
+    BugPattern annotation = symbol.getAnnotation(BugPattern.class);
+    if (annotation == null) {
+      return Optional.empty();
+    }
+
+    return Optional.of(
+        BugPatternDocumentation.create(
+            state.getPath().getCompilationUnit().getSourceFile().toUri(),
+            symbol.getQualifiedName().toString(),
+            annotation.name().isEmpty() ? tree.getSimpleName().toString() : annotation.name(),
+            ImmutableList.copyOf(annotation.altNames()),
+            annotation.link(),
+            ImmutableList.copyOf(annotation.tags()),
+            annotation.summary(),
+            annotation.explanation(),
+            annotation.severity(),
+            annotation.disableable(),
+            annotation.documentSuppression()
+                ? getSuppressionAnnotations(tree)
+                : ImmutableList.of()));
   }
 
   /**
@@ -79,7 +94,36 @@ final class BugPatternExtractor implements Extractor<BugPatternDocumentation> {
   }
 
   @AutoValue
+  @JsonDeserialize(as = AutoValue_BugPatternExtractor_BugPatternDocumentation.class)
   abstract static class BugPatternDocumentation {
+    static BugPatternDocumentation create(
+        URI source,
+        String fullyQualifiedName,
+        String name,
+        ImmutableList<String> altNames,
+        String link,
+        ImmutableList<String> tags,
+        String summary,
+        String explanation,
+        SeverityLevel severityLevel,
+        boolean canDisable,
+        ImmutableList<String> suppressionAnnotations) {
+      return new AutoValue_BugPatternExtractor_BugPatternDocumentation(
+          source,
+          fullyQualifiedName,
+          name,
+          altNames,
+          link,
+          tags,
+          summary,
+          explanation,
+          severityLevel,
+          canDisable,
+          suppressionAnnotations);
+    }
+
+    abstract URI source();
+
     abstract String fullyQualifiedName();
 
     abstract String name();

documentation-support/src/main/java/tech/picnic/errorprone/documentation/BugPatternTestExtractor.java

@@ -0,0 +1,285 @@
+package tech.picnic.errorprone.documentation;
+
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
+import static java.util.function.Predicate.not;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.annotation.JsonPropertyOrder;
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.google.auto.service.AutoService;
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.annotations.Immutable;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.util.TreeScanner;
+import java.net.URI;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+import org.jspecify.annotations.Nullable;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCases;
+
+/**
+ * An {@link Extractor} that describes how to extract data from classes that test a {@code
+ * BugChecker}.
+ */
+// XXX: Handle other methods from `{BugCheckerRefactoring,Compilation}TestHelper`:
+// - Indicate which custom arguments are specified, if any.
+// - For replacement tests, indicate which `FixChooser` is used.
+// - ... (We don't use all optional features; TBD what else to support.)
+@Immutable
+@AutoService(Extractor.class)
+@SuppressWarnings("rawtypes" /* See https://github.com/google/auto/issues/870. */)
+public final class BugPatternTestExtractor implements Extractor<TestCases> {
+  /** Instantiates a new {@link BugPatternTestExtractor} instance. */
+  public BugPatternTestExtractor() {}
+
+  @Override
+  public String identifier() {
+    return "bugpattern-test";
+  }
+
+  @Override
+  public Optional<TestCases> tryExtract(ClassTree tree, VisitorState state) {
+    BugPatternTestCollector collector = new BugPatternTestCollector();
+
+    collector.scan(tree, state);
+
+    return Optional.of(collector.getCollectedTests())
+        .filter(not(ImmutableList::isEmpty))
+        .map(
+            tests ->
+                new AutoValue_BugPatternTestExtractor_TestCases(
+                    state.getPath().getCompilationUnit().getSourceFile().toUri(),
+                    ASTHelpers.getSymbol(tree).className(),
+                    tests));
+  }
+
+  private static final class BugPatternTestCollector
+      extends TreeScanner<@Nullable Void, VisitorState> {
+    private static final Matcher<ExpressionTree> COMPILATION_HELPER_DO_TEST =
+        instanceMethod()
+            .onDescendantOf("com.google.errorprone.CompilationTestHelper")
+            .named("doTest");
+    private static final Matcher<ExpressionTree> TEST_HELPER_NEW_INSTANCE =
+        staticMethod()
+            .onDescendantOfAny(
+                "com.google.errorprone.CompilationTestHelper",
+                "com.google.errorprone.BugCheckerRefactoringTestHelper")
+            .named("newInstance")
+            .withParameters(Class.class.getCanonicalName(), Class.class.getCanonicalName());
+    private static final Matcher<ExpressionTree> IDENTIFICATION_SOURCE_LINES =
+        instanceMethod()
+            .onDescendantOf("com.google.errorprone.CompilationTestHelper")
+            .named("addSourceLines");
+    private static final Matcher<ExpressionTree> REPLACEMENT_DO_TEST =
+        instanceMethod()
+            .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper")
+            .named("doTest");
+    private static final Matcher<ExpressionTree> REPLACEMENT_EXPECT_UNCHANGED =
+        instanceMethod()
+            .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper.ExpectOutput")
+            .named("expectUnchanged");
+    private static final Matcher<ExpressionTree> REPLACEMENT_OUTPUT_SOURCE_LINES =
+        instanceMethod()
+            .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper.ExpectOutput")
+            .namedAnyOf("addOutputLines", "expectUnchanged");
+
+    private final List<TestCase> collectedTestCases = new ArrayList<>();
+
+    private ImmutableList<TestCase> getCollectedTests() {
+      return ImmutableList.copyOf(collectedTestCases);
+    }
+
+    @Override
+    public @Nullable Void visitMethodInvocation(MethodInvocationTree node, VisitorState state) {
+      boolean isReplacementTest = REPLACEMENT_DO_TEST.matches(node, state);
+      if (isReplacementTest || COMPILATION_HELPER_DO_TEST.matches(node, state)) {
+        getClassUnderTest(node, state)
+            .ifPresent(
+                classUnderTest -> {
+                  List<TestEntry> entries = new ArrayList<>();
+                  if (isReplacementTest) {
+                    extractReplacementTestCases(node, entries, state);
+                  } else {
+                    extractIdentificationTestCases(node, entries, state);
+                  }
+
+                  if (!entries.isEmpty()) {
+                    collectedTestCases.add(
+                        new AutoValue_BugPatternTestExtractor_TestCase(
+                            classUnderTest, ImmutableList.copyOf(entries).reverse()));
+                  }
+                });
+      }
+
+      return super.visitMethodInvocation(node, state);
+    }
+
+    private static Optional<String> getClassUnderTest(
+        MethodInvocationTree tree, VisitorState state) {
+      if (TEST_HELPER_NEW_INSTANCE.matches(tree, state)) {
+        return Optional.ofNullable(ASTHelpers.getSymbol(tree.getArguments().get(0)))
+            .filter(s -> !s.type.allparams().isEmpty())
+            .map(s -> s.type.allparams().get(0).tsym.getQualifiedName().toString());
+      }
+
+      ExpressionTree receiver = ASTHelpers.getReceiver(tree);
+      return receiver instanceof MethodInvocationTree
+          ? getClassUnderTest((MethodInvocationTree) receiver, state)
+          : Optional.empty();
+    }
+
+    private static void extractIdentificationTestCases(
+        MethodInvocationTree tree, List<TestEntry> sink, VisitorState state) {
+      if (IDENTIFICATION_SOURCE_LINES.matches(tree, state)) {
+        String path = ASTHelpers.constValue(tree.getArguments().get(0), String.class);
+        Optional<String> sourceCode =
+            getSourceCode(tree).filter(s -> s.contains("// BUG: Diagnostic"));
+        if (path != null && sourceCode.isPresent()) {
+          sink.add(
+              new AutoValue_BugPatternTestExtractor_IdentificationTestEntry(
+                  path, sourceCode.orElseThrow()));
+        }
+      }
+
+      ExpressionTree receiver = ASTHelpers.getReceiver(tree);
+      if (receiver instanceof MethodInvocationTree) {
+        extractIdentificationTestCases((MethodInvocationTree) receiver, sink, state);
+      }
+    }
+
+    private static void extractReplacementTestCases(
+        MethodInvocationTree tree, List<TestEntry> sink, VisitorState state) {
+      if (REPLACEMENT_OUTPUT_SOURCE_LINES.matches(tree, state)) {
+        /*
+         * Retrieve the method invocation that contains the input source code. Note that this cast
+         * is safe, because this code is guarded by an earlier call to `#getClassUnderTest(..)`,
+         * which ensures that `tree` is part of a longer method invocation chain.
+         */
+        MethodInvocationTree inputTree = (MethodInvocationTree) ASTHelpers.getReceiver(tree);
+
+        String path = ASTHelpers.constValue(inputTree.getArguments().get(0), String.class);
+        Optional<String> inputCode = getSourceCode(inputTree);
+        if (path != null && inputCode.isPresent()) {
+          Optional<String> outputCode =
+              REPLACEMENT_EXPECT_UNCHANGED.matches(tree, state) ? inputCode : getSourceCode(tree);
+
+          if (outputCode.isPresent() && !inputCode.equals(outputCode)) {
+            sink.add(
+                new AutoValue_BugPatternTestExtractor_ReplacementTestEntry(
+                    path, inputCode.orElseThrow(), outputCode.orElseThrow()));
+          }
+        }
+      }
+
+      ExpressionTree receiver = ASTHelpers.getReceiver(tree);
+      if (receiver instanceof MethodInvocationTree) {
+        extractReplacementTestCases((MethodInvocationTree) receiver, sink, state);
+      }
+    }
+
+    // XXX: This logic is duplicated in `ErrorProneTestSourceFormat`. Can we do better?
+    private static Optional<String> getSourceCode(MethodInvocationTree tree) {
+      List<? extends ExpressionTree> sourceLines =
+          tree.getArguments().subList(1, tree.getArguments().size());
+      StringBuilder source = new StringBuilder();
+
+      for (ExpressionTree sourceLine : sourceLines) {
+        String value = ASTHelpers.constValue(sourceLine, String.class);
+        if (value == null) {
+          return Optional.empty();
+        }
+        source.append(value).append('\n');
+      }
+
+      return Optional.of(source.toString());
+    }
+  }
+
+  @AutoValue
+  @JsonDeserialize(as = AutoValue_BugPatternTestExtractor_TestCases.class)
+  abstract static class TestCases {
+    static TestCases create(URI source, String testClass, ImmutableList<TestCase> testCases) {
+      return new AutoValue_BugPatternTestExtractor_TestCases(source, testClass, testCases);
+    }
+
+    abstract URI source();
+
+    abstract String testClass();
+
+    abstract ImmutableList<TestCase> testCases();
+  }
+
+  @AutoValue
+  @JsonDeserialize(as = AutoValue_BugPatternTestExtractor_TestCase.class)
+  abstract static class TestCase {
+    static TestCase create(String classUnderTest, ImmutableList<TestEntry> entries) {
+      return new AutoValue_BugPatternTestExtractor_TestCase(classUnderTest, entries);
+    }
+
+    abstract String classUnderTest();
+
+    abstract ImmutableList<TestEntry> entries();
+  }
+
+  @JsonSubTypes({
+    @JsonSubTypes.Type(AutoValue_BugPatternTestExtractor_IdentificationTestEntry.class),
+    @JsonSubTypes.Type(AutoValue_BugPatternTestExtractor_ReplacementTestEntry.class)
+  })
+  @JsonTypeInfo(include = As.EXISTING_PROPERTY, property = "type", use = JsonTypeInfo.Id.DEDUCTION)
+  @JsonIgnoreProperties(ignoreUnknown = true)
+  @JsonPropertyOrder("type")
+  interface TestEntry {
+    TestType type();
+
+    String path();
+
+    enum TestType {
+      IDENTIFICATION,
+      REPLACEMENT
+    }
+  }
+
+  @AutoValue
+  abstract static class IdentificationTestEntry implements TestEntry {
+    static IdentificationTestEntry create(String path, String code) {
+      return new AutoValue_BugPatternTestExtractor_IdentificationTestEntry(path, code);
+    }
+
+    @JsonProperty
+    @Override
+    public final TestType type() {
+      return TestType.IDENTIFICATION;
+    }
+
+    abstract String code();
+  }
+
+  @AutoValue
+  abstract static class ReplacementTestEntry implements TestEntry {
+    static ReplacementTestEntry create(String path, String input, String output) {
+      return new AutoValue_BugPatternTestExtractor_ReplacementTestEntry(path, input, output);
+    }
+
+    @JsonProperty
+    @Override
+    public final TestType type() {
+      return TestType.REPLACEMENT;
+    }
+
+    abstract String input();
+
+    abstract String output();
+  }
+}

documentation-support/src/main/java/tech/picnic/errorprone/documentation/DocumentationGeneratorTaskListener.java

@@ -1,24 +1,21 @@
 package tech.picnic.errorprone.documentation;
 
-import static java.nio.charset.StandardCharsets.UTF_8;
-
-import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
-import com.fasterxml.jackson.annotation.PropertyAccessor;
-import com.fasterxml.jackson.databind.ObjectMapper;
+import com.google.common.collect.ImmutableList;
+import com.google.errorprone.VisitorState;
 import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.CompilationUnitTree;
 import com.sun.source.util.TaskEvent;
 import com.sun.source.util.TaskEvent.Kind;
 import com.sun.source.util.TaskListener;
+import com.sun.source.util.TreePath;
 import com.sun.tools.javac.api.JavacTrees;
 import com.sun.tools.javac.util.Context;
-import java.io.File;
-import java.io.FileWriter;
 import java.io.IOException;
-import java.io.UncheckedIOException;
 import java.net.URI;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.ServiceLoader;
 import javax.tools.JavaFileObject;
 
 /**
@@ -27,8 +24,12 @@ import javax.tools.JavaFileObject;
  */
 // XXX: Find a better name for this class; it doesn't generate documentation per se.
 final class DocumentationGeneratorTaskListener implements TaskListener {
-  private static final ObjectMapper OBJECT_MAPPER =
-      new ObjectMapper().setVisibility(PropertyAccessor.FIELD, Visibility.ANY);
+  @SuppressWarnings({"rawtypes", "unchecked"})
+  private static final ImmutableList<Extractor<?>> EXTRACTORS =
+      (ImmutableList)
+          ImmutableList.copyOf(
+              ServiceLoader.load(
+                  Extractor.class, DocumentationGeneratorTaskListener.class.getClassLoader()));
 
   private final Context context;
   private final Path docsPath;
@@ -51,19 +52,25 @@ final class DocumentationGeneratorTaskListener implements TaskListener {
       return;
     }
 
-    ClassTree classTree = JavacTrees.instance(context).getTree(taskEvent.getTypeElement());
     JavaFileObject sourceFile = taskEvent.getSourceFile();
-    if (classTree == null || sourceFile == null) {
+    CompilationUnitTree compilationUnit = taskEvent.getCompilationUnit();
+    ClassTree classTree = JavacTrees.instance(context).getTree(taskEvent.getTypeElement());
+    if (sourceFile == null || compilationUnit == null || classTree == null) {
       return;
     }
 
-    ExtractorType.findMatchingType(classTree)
-        .ifPresent(
-            extractorType ->
-                writeToFile(
-                    extractorType.getIdentifier(),
-                    getSimpleClassName(sourceFile.toUri()),
-                    extractorType.getExtractor().extract(classTree, context)));
+    VisitorState state =
+        VisitorState.createForUtilityPurposes(context)
+            .withPath(new TreePath(new TreePath(compilationUnit), classTree));
+
+    for (Extractor<?> extractor : EXTRACTORS) {
+      extractor
+          .tryExtract(classTree, state)
+          .ifPresent(
+              data ->
+                  writeToFile(
+                      extractor.identifier(), getSimpleClassName(sourceFile.toUri()), data));
+    }
   }
 
   private void createDocsDirectory() {
@@ -76,13 +83,7 @@ final class DocumentationGeneratorTaskListener implements TaskListener {
   }
 
   private <T> void writeToFile(String identifier, String className, T data) {
-    File file = docsPath.resolve(String.format("%s-%s.json", identifier, className)).toFile();
-
-    try (FileWriter fileWriter = new FileWriter(file, UTF_8)) {
-      OBJECT_MAPPER.writeValue(fileWriter, data);
-    } catch (IOException e) {
-      throw new UncheckedIOException(String.format("Cannot write to file '%s'", file.getPath()), e);
-    }
+    Json.write(docsPath.resolve(String.format("%s-%s.json", identifier, className)), data);
   }
 
   private static String getSimpleClassName(URI path) {

documentation-support/src/main/java/tech/picnic/errorprone/documentation/Extractor.java

@@ -1,8 +1,9 @@
 package tech.picnic.errorprone.documentation;
 
+import com.google.errorprone.VisitorState;
 import com.google.errorprone.annotations.Immutable;
 import com.sun.source.tree.ClassTree;
-import com.sun.tools.javac.util.Context;
+import java.util.Optional;
 
 /**
  * Interface implemented by classes that define how to extract data of some type {@link T} from a
@@ -13,21 +14,20 @@ import com.sun.tools.javac.util.Context;
 @Immutable
 interface Extractor<T> {
   /**
-   * Extracts and returns an instance of {@link T} using the provided arguments.
+   * Returns the unique identifier of this extractor.
    *
-   * @param tree The {@link ClassTree} to analyze and from which to extract instances of {@link T}.
-   * @param context The {@link Context} in which the current compilation takes place.
-   * @return A non-null instance of {@link T}.
+   * @return A non-{@code null} string.
    */
-  // XXX: Drop `Context` parameter unless used.
-  T extract(ClassTree tree, Context context);
+  String identifier();
 
   /**
-   * Tells whether this {@link Extractor} can extract documentation content from the given {@link
-   * ClassTree}.
+   * Attempts to extract an instance of type {@link T} using the provided arguments.
    *
-   * @param tree The {@link ClassTree} of interest.
-   * @return {@code true} iff data extraction is supported.
+   * @param tree The {@link ClassTree} to analyze and from which to extract an instance of type
+   *     {@link T}.
+   * @param state A {@link VisitorState} describing the context in which the given {@link ClassTree}
+   *     is found.
+   * @return An instance of type {@link T}, if possible.
    */
-  boolean canExtract(ClassTree tree);
+  Optional<T> tryExtract(ClassTree tree, VisitorState state);
 }

documentation-support/src/main/java/tech/picnic/errorprone/documentation/ExtractorType.java

@@ -1,36 +0,0 @@
-package tech.picnic.errorprone.documentation;
-
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Sets;
-import com.sun.source.tree.ClassTree;
-import java.util.EnumSet;
-import java.util.Optional;
-
-/** An enumeration of {@link Extractor} types. */
-enum ExtractorType {
-  BUG_PATTERN("bugpattern", new BugPatternExtractor());
-
-  private static final ImmutableSet<ExtractorType> TYPES =
-      Sets.immutableEnumSet(EnumSet.allOf(ExtractorType.class));
-
-  private final String identifier;
-  private final Extractor<?> extractor;
-
-  ExtractorType(String identifier, Extractor<?> extractor) {
-    this.identifier = identifier;
-    this.extractor = extractor;
-  }
-
-  String getIdentifier() {
-    return identifier;
-  }
-
-  @SuppressWarnings("java:S1452" /* The extractor returns data of an unspecified type. */)
-  Extractor<?> getExtractor() {
-    return extractor;
-  }
-
-  static Optional<ExtractorType> findMatchingType(ClassTree tree) {
-    return TYPES.stream().filter(type -> type.getExtractor().canExtract(tree)).findFirst();
-  }
-}

documentation-support/src/main/java/tech/picnic/errorprone/documentation/Json.java

@@ -0,0 +1,45 @@
+package tech.picnic.errorprone.documentation;
+
+import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.datatype.guava.GuavaModule;
+import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
+import com.google.errorprone.annotations.FormatMethod;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Path;
+
+/**
+ * Utility class that offers mutually consistent JSON serialization and deserialization operations,
+ * without further specifying the exact schema used.
+ */
+final class Json {
+  private static final ObjectMapper OBJECT_MAPPER =
+      new ObjectMapper()
+          .setVisibility(PropertyAccessor.FIELD, Visibility.ANY)
+          .registerModules(new GuavaModule(), new ParameterNamesModule());
+
+  private Json() {}
+
+  static <T> T read(Path path, Class<T> clazz) {
+    try {
+      return OBJECT_MAPPER.readValue(path.toFile(), clazz);
+    } catch (IOException e) {
+      throw failure(e, "Failure reading from '%s'", path);
+    }
+  }
+
+  static <T> void write(Path path, T object) {
+    try {
+      OBJECT_MAPPER.writeValue(path.toFile(), object);
+    } catch (IOException e) {
+      throw failure(e, "Failure writing to '%s'", path);
+    }
+  }
+
+  @FormatMethod
+  private static UncheckedIOException failure(IOException cause, String format, Object... args) {
+    return new UncheckedIOException(String.format(format, args), cause);
+  }
+}

documentation-support/src/test/java/tech/picnic/errorprone/documentation/BugPatternExtractorTest.java

@@ -1,22 +1,17 @@
 package tech.picnic.errorprone.documentation;
 
 import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
-import static java.nio.charset.StandardCharsets.UTF_8;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
-import com.google.common.io.Resources;
+import com.google.common.collect.ImmutableList;
 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.ClassTreeMatcher;
-import com.google.errorprone.matchers.Description;
-import com.sun.source.tree.ClassTree;
-import java.io.IOException;
+import java.net.URI;
 import java.nio.file.Path;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import tech.picnic.errorprone.documentation.BugPatternExtractor.BugPatternDocumentation;
 
 final class BugPatternExtractorTest {
   @Test
@@ -32,7 +27,7 @@ final class BugPatternExtractorTest {
   }
 
   @Test
-  void minimalBugPattern(@TempDir Path outputDirectory) throws IOException {
+  void minimalBugPattern(@TempDir Path outputDirectory) {
     Compilation.compileWithDocumentationGenerator(
         outputDirectory,
         "MinimalBugChecker.java",
@@ -45,14 +40,25 @@ final class BugPatternExtractorTest {
         "@BugPattern(summary = \"MinimalBugChecker summary\", severity = SeverityLevel.ERROR)",
         "public final class MinimalBugChecker extends BugChecker {}");
 
-    verifyFileMatchesResource(
+    verifyGeneratedFileContent(
         outputDirectory,
-        "bugpattern-MinimalBugChecker.json",
-        "bugpattern-documentation-minimal.json");
+        "MinimalBugChecker",
+        BugPatternDocumentation.create(
+            URI.create("file:///MinimalBugChecker.java"),
+            "pkg.MinimalBugChecker",
+            "MinimalBugChecker",
+            ImmutableList.of(),
+            "",
+            ImmutableList.of(),
+            "MinimalBugChecker summary",
+            "",
+            ERROR,
+            /* canDisable= */ true,
+            ImmutableList.of(SuppressWarnings.class.getCanonicalName())));
   }
 
   @Test
-  void completeBugPattern(@TempDir Path outputDirectory) throws IOException {
+  void completeBugPattern(@TempDir Path outputDirectory) {
     Compilation.compileWithDocumentationGenerator(
         outputDirectory,
         "CompleteBugChecker.java",
@@ -76,14 +82,25 @@ final class BugPatternExtractorTest {
         "    suppressionAnnotations = {BugPattern.class, Test.class})",
         "public final class CompleteBugChecker extends BugChecker {}");
 
-    verifyFileMatchesResource(
+    verifyGeneratedFileContent(
         outputDirectory,
-        "bugpattern-CompleteBugChecker.json",
-        "bugpattern-documentation-complete.json");
+        "CompleteBugChecker",
+        BugPatternDocumentation.create(
+            URI.create("file:///CompleteBugChecker.java"),
+            "pkg.CompleteBugChecker",
+            "OtherName",
+            ImmutableList.of("Check"),
+            "https://error-prone.picnic.tech",
+            ImmutableList.of("Simplification"),
+            "CompleteBugChecker summary",
+            "Example explanation",
+            SUGGESTION,
+            /* canDisable= */ false,
+            ImmutableList.of(BugPattern.class.getCanonicalName(), "org.junit.jupiter.api.Test")));
   }
 
   @Test
-  void undocumentedSuppressionBugPattern(@TempDir Path outputDirectory) throws IOException {
+  void undocumentedSuppressionBugPattern(@TempDir Path outputDirectory) {
     Compilation.compileWithDocumentationGenerator(
         outputDirectory,
         "UndocumentedSuppressionBugPattern.java",
@@ -99,55 +116,27 @@ final class BugPatternExtractorTest {
         "    documentSuppression = false)",
         "public final class UndocumentedSuppressionBugPattern extends BugChecker {}");
 
-    verifyFileMatchesResource(
+    verifyGeneratedFileContent(
         outputDirectory,
-        "bugpattern-UndocumentedSuppressionBugPattern.json",
-        "bugpattern-documentation-undocumented-suppression.json");
-  }
-
-  @Test
-  void bugPatternAnnotationIsAbsent() {
-    CompilationTestHelper.newInstance(TestChecker.class, getClass())
-        .addSourceLines(
-            "TestChecker.java",
-            "import com.google.errorprone.bugpatterns.BugChecker;",
+        "UndocumentedSuppressionBugPattern",
+        BugPatternDocumentation.create(
+            URI.create("file:///UndocumentedSuppressionBugPattern.java"),
+            "pkg.UndocumentedSuppressionBugPattern",
+            "UndocumentedSuppressionBugPattern",
+            ImmutableList.of(),
             "",
-            "// BUG: Diagnostic contains: Can extract: false",
-            "public final class TestChecker extends BugChecker {}")
-        .doTest();
+            ImmutableList.of(),
+            "UndocumentedSuppressionBugPattern summary",
+            "",
+            WARNING,
+            /* canDisable= */ true,
+            ImmutableList.of()));
   }
 
-  private static void verifyFileMatchesResource(
-      Path outputDirectory, String fileName, String resourceName) throws IOException {
-    assertThat(outputDirectory.resolve(fileName))
-        .content(UTF_8)
-        .isEqualToIgnoringWhitespace(getResource(resourceName));
-  }
-
-  // XXX: Once we support only JDK 15+, drop this method in favour of including the resources as
-  // text blocks in this class. (This also requires renaming the `verifyFileMatchesResource`
-  // method.)
-  private static String getResource(String resourceName) throws IOException {
-    return Resources.toString(
-        Resources.getResource(BugPatternExtractorTest.class, resourceName), UTF_8);
-  }
-
-  /** A {@link BugChecker} that validates the {@link BugPatternExtractor}. */
-  @BugPattern(summary = "Validates `BugPatternExtractor` extraction", 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) {
-      BugPatternExtractor extractor = new BugPatternExtractor();
-
-      assertThatThrownBy(() -> extractor.extract(tree, state.context))
-          .isInstanceOf(NullPointerException.class)
-          .hasMessage("BugPattern annotation must be present");
-
-      return buildDescription(tree)
-          .setMessage(String.format("Can extract: %s", extractor.canExtract(tree)))
-          .build();
-    }
+  private static void verifyGeneratedFileContent(
+      Path outputDirectory, String testClass, BugPatternDocumentation expected) {
+    assertThat(outputDirectory.resolve(String.format("bugpattern-%s.json", testClass)))
+        .exists()
+        .returns(expected, path -> Json.read(path, BugPatternDocumentation.class));
   }
 }

documentation-support/src/test/java/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest.java

@@ -0,0 +1,558 @@
+package tech.picnic.errorprone.documentation;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.google.common.collect.ImmutableList;
+import java.net.URI;
+import java.nio.file.Path;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.IdentificationTestEntry;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.ReplacementTestEntry;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCase;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCases;
+
+final class BugPatternTestExtractorTest {
+  @Test
+  void noTestClass(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerWithoutAnnotation.java",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "public final class TestCheckerWithoutAnnotation extends BugChecker {}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void noDoTestInvocation(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class TestCheckerTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\");",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\");",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void nullBugCheckerInstance(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class TestCheckerTest {",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance((Class<BugChecker>) null, getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance((Class<BugChecker>) null, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void rawBugCheckerInstance(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class TestCheckerTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  @SuppressWarnings(\"unchecked\")",
+        "  void m() {",
+        "    @SuppressWarnings(\"rawtypes\")",
+        "    Class bugChecker = TestChecker.class;",
+        "",
+        "    CompilationTestHelper.newInstance(bugChecker, getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(bugChecker, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void scannerSupplierInstance(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "import com.google.errorprone.scanner.ScannerSupplier;",
+        "",
+        "final class TestCheckerTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(",
+        "            ScannerSupplier.fromBugCheckerClasses(TestChecker.class), getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(",
+        "            ScannerSupplier.fromBugCheckerClasses(TestChecker.class), getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void nonCompileTimeConstantStrings(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class TestCheckerTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addSourceLines(toString() + \"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .addSourceLines(\"B.java\", \"// BUG: Diagnostic contains:\", \"class B {}\", toString())",
+        "        .doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addInputLines(toString() + \"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .addInputLines(\"B.java\", \"class B {}\", toString())",
+        "        .addOutputLines(\"B.java\", \"class B { /* This is a change. */ }\")",
+        "        .addInputLines(\"C.java\", \"class C {}\")",
+        "        .addOutputLines(\"C.java\", \"class C { /* This is a change. */ }\", toString())",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void nonFluentTestHelperExpressions(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class TestCheckerTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper testHelper =",
+        "        CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "            .addSourceLines(\"A.java\", \"class A {}\");",
+        "    testHelper.doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.ExpectOutput expectedOutput =",
+        "        BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "            .addInputLines(\"A.java\", \"class A {}\");",
+        "    expectedOutput.addOutputLines(\"A.java\", \"class A {}\").doTest();",
+        "    expectedOutput.expectUnchanged().doTest();",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void noSource(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class TestCheckerTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass()).doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass()).doTest();",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void noDiagnostics(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "TestCheckerTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class TestCheckerTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addSourceLines(\"A.java\", \"class A {}\")",
+        "        .doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A {}\")",
+        "        .addInputLines(\"B.java\", \"class B {}\")",
+        "        .expectUnchanged()",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
+  }
+
+  @Test
+  void singleFileCompilationTestHelper(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "SingleFileCompilationTestHelperTest.java",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class SingleFileCompilationTestHelperTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "SingleFileCompilationTestHelperTest",
+        TestCases.create(
+            URI.create("file:///SingleFileCompilationTestHelperTest.java"),
+            "SingleFileCompilationTestHelperTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "SingleFileCompilationTestHelperTest.TestChecker",
+                    ImmutableList.of(
+                        IdentificationTestEntry.create(
+                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))))));
+  }
+
+  @Test
+  void singleFileCompilationTestHelperWithSetArgs(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "SingleFileCompilationTestHelperWithSetArgsTest.java",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class SingleFileCompilationTestHelperWithSetArgsTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .setArgs(\"-XepAllSuggestionsAsWarnings\")",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "SingleFileCompilationTestHelperWithSetArgsTest",
+        TestCases.create(
+            URI.create("file:///SingleFileCompilationTestHelperWithSetArgsTest.java"),
+            "SingleFileCompilationTestHelperWithSetArgsTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "SingleFileCompilationTestHelperWithSetArgsTest.TestChecker",
+                    ImmutableList.of(
+                        IdentificationTestEntry.create(
+                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))))));
+  }
+
+  @Test
+  void multiFileCompilationTestHelper(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "MultiFileCompilationTestHelperTest.java",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class MultiFileCompilationTestHelperTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .addSourceLines(\"B.java\", \"// BUG: Diagnostic contains:\", \"class B {}\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "MultiFileCompilationTestHelperTest",
+        TestCases.create(
+            URI.create("file:///MultiFileCompilationTestHelperTest.java"),
+            "MultiFileCompilationTestHelperTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "MultiFileCompilationTestHelperTest.TestChecker",
+                    ImmutableList.of(
+                        IdentificationTestEntry.create(
+                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"),
+                        IdentificationTestEntry.create(
+                            "B.java", "// BUG: Diagnostic contains:\nclass B {}\n"))))));
+  }
+
+  @Test
+  void singleFileBugCheckerRefactoringTestHelper(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "SingleFileBugCheckerRefactoringTestHelperTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class SingleFileBugCheckerRefactoringTestHelperTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "SingleFileBugCheckerRefactoringTestHelperTest",
+        TestCases.create(
+            URI.create("file:///SingleFileBugCheckerRefactoringTestHelperTest.java"),
+            "SingleFileBugCheckerRefactoringTestHelperTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "SingleFileBugCheckerRefactoringTestHelperTest.TestChecker",
+                    ImmutableList.of(
+                        ReplacementTestEntry.create(
+                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+  }
+
+  @Test
+  void singleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestMode(
+      @TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .setArgs(\"-XepAllSuggestionsAsWarnings\")",
+        "        .setFixChooser(FixChoosers.SECOND)",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .doTest(TestMode.TEXT_MATCH);",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest",
+        TestCases.create(
+            URI.create(
+                "file:///SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.java"),
+            "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.TestChecker",
+                    ImmutableList.of(
+                        ReplacementTestEntry.create(
+                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+  }
+
+  @Test
+  void multiFileBugCheckerRefactoringTestHelper(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "MultiFileBugCheckerRefactoringTestHelperTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class MultiFileBugCheckerRefactoringTestHelperTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .addInputLines(\"B.java\", \"class B {}\")",
+        "        .addOutputLines(\"B.java\", \"class B { /* This is a change. */ }\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "MultiFileBugCheckerRefactoringTestHelperTest",
+        TestCases.create(
+            URI.create("file:///MultiFileBugCheckerRefactoringTestHelperTest.java"),
+            "MultiFileBugCheckerRefactoringTestHelperTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "MultiFileBugCheckerRefactoringTestHelperTest.TestChecker",
+                    ImmutableList.of(
+                        ReplacementTestEntry.create(
+                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"),
+                        ReplacementTestEntry.create(
+                            "B.java", "class B {}\n", "class B { /* This is a change. */ }\n"))))));
+  }
+
+  @Test
+  void compilationAndBugCheckerRefactoringTestHelpers(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "CompilationAndBugCheckerRefactoringTestHelpersTest.java",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class CompilationAndBugCheckerRefactoringTestHelpersTest {",
+        "  private static class TestChecker extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(TestChecker.class, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "CompilationAndBugCheckerRefactoringTestHelpersTest",
+        TestCases.create(
+            URI.create("file:///CompilationAndBugCheckerRefactoringTestHelpersTest.java"),
+            "CompilationAndBugCheckerRefactoringTestHelpersTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
+                    ImmutableList.of(
+                        IdentificationTestEntry.create(
+                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))),
+                TestCase.create(
+                    "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
+                    ImmutableList.of(
+                        ReplacementTestEntry.create(
+                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+  }
+
+  @Test
+  void compilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNames(
+      @TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.java",
+        "package pkg;",
+        "",
+        "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+        "import com.google.errorprone.CompilationTestHelper;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "final class CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest {",
+        "  private static class CustomTestChecker extends BugChecker {}",
+        "",
+        "  private static class CustomTestChecker2 extends BugChecker {}",
+        "",
+        "  void m() {",
+        "    CompilationTestHelper.newInstance(CustomTestChecker.class, getClass())",
+        "        .addSourceLines(\"A.java\", \"// BUG: Diagnostic contains:\", \"class A {}\")",
+        "        .doTest();",
+        "",
+        "    BugCheckerRefactoringTestHelper.newInstance(CustomTestChecker2.class, getClass())",
+        "        .addInputLines(\"A.java\", \"class A {}\")",
+        "        .addOutputLines(\"A.java\", \"class A { /* This is a change. */ }\")",
+        "        .doTest();",
+        "  }",
+        "}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest",
+        TestCases.create(
+            URI.create(
+                "file:///CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.java"),
+            "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest",
+            ImmutableList.of(
+                TestCase.create(
+                    "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker",
+                    ImmutableList.of(
+                        IdentificationTestEntry.create(
+                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))),
+                TestCase.create(
+                    "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker2",
+                    ImmutableList.of(
+                        ReplacementTestEntry.create(
+                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+  }
+
+  private static void verifyGeneratedFileContent(
+      Path outputDirectory, String testClass, TestCases expected) {
+    assertThat(outputDirectory.resolve(String.format("bugpattern-test-%s.json", testClass)))
+        .exists()
+        .returns(expected, path -> Json.read(path, TestCases.class));
+  }
+}

documentation-support/src/test/java/tech/picnic/errorprone/documentation/Compilation.java

@@ -1,5 +1,7 @@
 package tech.picnic.errorprone.documentation;
 
+import static org.assertj.core.api.Assertions.assertThat;
+
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.FileManagers;
 import com.google.errorprone.FileObjects;
@@ -7,39 +9,66 @@ import com.sun.tools.javac.api.JavacTaskImpl;
 import com.sun.tools.javac.api.JavacTool;
 import com.sun.tools.javac.file.JavacFileManager;
 import java.nio.file.Path;
+import java.util.ArrayList;
+import java.util.List;
+import javax.tools.Diagnostic;
 import javax.tools.JavaCompiler;
 import javax.tools.JavaFileObject;
 
 // XXX: Generalize and move this class so that it can also be used by `refaster-compiler`.
-// XXX: Add support for this class to the `ErrorProneTestHelperSourceFormat` check.
+// XXX: This class is supported by the `ErrorProneTestHelperSourceFormat` check, but until that
+// support is covered by unit tests, make sure to update that logic if this class or its methods are
+// moved/renamed.
 public final class Compilation {
   private Compilation() {}
 
   public static void compileWithDocumentationGenerator(
-      Path outputDirectory, String fileName, String... lines) {
-    compileWithDocumentationGenerator(outputDirectory.toAbsolutePath().toString(), fileName, lines);
+      Path outputDirectory, String path, String... lines) {
+    compileWithDocumentationGenerator(outputDirectory.toAbsolutePath().toString(), path, lines);
   }
 
   public static void compileWithDocumentationGenerator(
-      String outputDirectory, String fileName, String... lines) {
+      String outputDirectory, String path, String... lines) {
+    /*
+     * The compiler options specified here largely match those used by Error Prone's
+     * `CompilationTestHelper`. A key difference is the stricter linting configuration. When
+     * compiling using JDK 21+, these lint options also require that certain JDK modules are
+     * explicitly exported.
+     */
     compile(
-        ImmutableList.of("-Xplugin:DocumentationGenerator -XoutputDirectory=" + outputDirectory),
-        FileObjects.forSourceLines(fileName, lines));
+        ImmutableList.of(
+            "--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED",
+            "--add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED",
+            "--add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED",
+            "-encoding",
+            "UTF-8",
+            "-parameters",
+            "-proc:none",
+            "-Werror",
+            "-Xlint:all,-serial",
+            "-Xplugin:DocumentationGenerator -XoutputDirectory=" + outputDirectory,
+            "-XDdev",
+            "-XDcompilePolicy=simple"),
+        FileObjects.forSourceLines(path, lines));
   }
 
   private static void compile(ImmutableList<String> options, JavaFileObject javaFileObject) {
     JavacFileManager javacFileManager = FileManagers.testFileManager();
     JavaCompiler compiler = JavacTool.create();
+
+    List<Diagnostic<?>> diagnostics = new ArrayList<>();
     JavacTaskImpl task =
         (JavacTaskImpl)
             compiler.getTask(
                 null,
                 javacFileManager,
-                null,
+                diagnostics::add,
                 options,
                 ImmutableList.of(),
                 ImmutableList.of(javaFileObject));
 
-    task.call();
+    Boolean result = task.call();
+    assertThat(diagnostics).isEmpty();
+    assertThat(result).isTrue();
   }
 }

documentation-support/src/test/java/tech/picnic/errorprone/documentation/DocumentationGeneratorTaskListenerTest.java

@@ -1,19 +1,29 @@
 package tech.picnic.errorprone.documentation;
 
 import static com.google.common.collect.ImmutableList.toImmutableList;
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.nio.file.attribute.AclEntryPermission.ADD_SUBDIRECTORY;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
 import static org.junit.jupiter.api.condition.OS.WINDOWS;
 
+import com.google.auto.service.AutoService;
+import com.google.auto.value.AutoValue;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
+import com.google.common.collect.Streams;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.annotations.Immutable;
+import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.Tree;
 import java.io.IOException;
 import java.nio.file.FileSystemException;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.attribute.AclEntry;
 import java.nio.file.attribute.AclFileAttributeView;
+import java.util.Optional;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.condition.DisabledOnOs;
 import org.junit.jupiter.api.condition.EnabledOnOs;
@@ -75,4 +85,56 @@ final class DocumentationGeneratorTaskListenerTest {
         .isInstanceOf(IllegalArgumentException.class)
         .hasMessage("Precisely one path must be provided");
   }
+
+  @Test
+  void extraction(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "DocumentationGeneratorTaskListenerTestClass.java",
+        "class DocumentationGeneratorTaskListenerTestClass {}");
+
+    // XXX: Once we support only JDK 15+, use a text block for the `expected` string.
+    assertThat(
+            outputDirectory.resolve(
+                "documentation-generator-task-listener-test-DocumentationGeneratorTaskListenerTestClass.json"))
+        .content(UTF_8)
+        .isEqualToIgnoringWhitespace(
+            "{\"className\":\"DocumentationGeneratorTaskListenerTestClass\",\"path\":[\"CLASS: DocumentationGeneratorTaskListenerTestClass\",\"COMPILATION_UNIT\"]}");
+  }
+
+  @Immutable
+  @AutoService(Extractor.class)
+  @SuppressWarnings("rawtypes" /* See https://github.com/google/auto/issues/870. */)
+  public static final class TestExtractor implements Extractor<ExtractionParameters> {
+    @Override
+    public String identifier() {
+      return "documentation-generator-task-listener-test";
+    }
+
+    @Override
+    public Optional<ExtractionParameters> tryExtract(ClassTree tree, VisitorState state) {
+      return Optional.of(tree.getSimpleName().toString())
+          .filter(n -> n.contains(DocumentationGeneratorTaskListenerTest.class.getSimpleName()))
+          .map(
+              className ->
+                  new AutoValue_DocumentationGeneratorTaskListenerTest_ExtractionParameters(
+                      className,
+                      Streams.stream(state.getPath())
+                          .map(TestExtractor::describeTree)
+                          .collect(toImmutableList())));
+    }
+
+    private static String describeTree(Tree tree) {
+      return (tree instanceof ClassTree)
+          ? String.join(": ", String.valueOf(tree.getKind()), ((ClassTree) tree).getSimpleName())
+          : tree.getKind().toString();
+    }
+  }
+
+  @AutoValue
+  abstract static class ExtractionParameters {
+    abstract String className();
+
+    abstract ImmutableList<String> path();
+  }
 }

documentation-support/src/test/java/tech/picnic/errorprone/documentation/JsonTest.java

@@ -0,0 +1,62 @@
+package tech.picnic.errorprone.documentation;
+
+import static java.nio.charset.StandardCharsets.UTF_8;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.google.auto.value.AutoValue;
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.UncheckedIOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.io.TempDir;
+
+final class JsonTest {
+  private static final TestObject TEST_OBJECT = new AutoValue_JsonTest_TestObject("foo", 42);
+  private static final String TEST_JSON = "{\"string\":\"foo\",\"number\":42}";
+
+  @Test
+  void write(@TempDir Path directory) {
+    Path file = directory.resolve("test.json");
+
+    Json.write(file, TEST_OBJECT);
+
+    assertThat(file).content(UTF_8).isEqualTo(TEST_JSON);
+  }
+
+  @Test
+  void writeFailure(@TempDir Path directory) {
+    assertThatThrownBy(() -> Json.write(directory, TEST_OBJECT))
+        .isInstanceOf(UncheckedIOException.class)
+        .hasMessageContaining("Failure writing to '%s'", directory)
+        .hasCauseInstanceOf(FileNotFoundException.class);
+  }
+
+  @Test
+  void read(@TempDir Path directory) throws IOException {
+    Path file = directory.resolve("test.json");
+
+    Files.writeString(file, TEST_JSON, UTF_8);
+
+    assertThat(Json.read(file, TestObject.class)).isEqualTo(TEST_OBJECT);
+  }
+
+  @Test
+  void readFailure(@TempDir Path directory) {
+    assertThatThrownBy(() -> Json.read(directory, TestObject.class))
+        .isInstanceOf(UncheckedIOException.class)
+        .hasMessageContaining("Failure reading from '%s'", directory)
+        .hasCauseInstanceOf(FileNotFoundException.class);
+  }
+
+  @AutoValue
+  @JsonDeserialize(as = AutoValue_JsonTest_TestObject.class)
+  abstract static class TestObject {
+    abstract String string();
+
+    abstract int number();
+  }
+}

documentation-support/src/test/resources/tech/picnic/errorprone/documentation/bugpattern-documentation-complete.json

@@ -1,19 +0,0 @@
-{
-  "fullyQualifiedName": "pkg.CompleteBugChecker",
-  "name": "OtherName",
-  "altNames": [
-    "Check"
-  ],
-  "link": "https://error-prone.picnic.tech",
-  "tags": [
-    "Simplification"
-  ],
-  "summary": "CompleteBugChecker summary",
-  "explanation": "Example explanation",
-  "severityLevel": "SUGGESTION",
-  "canDisable": false,
-  "suppressionAnnotations": [
-    "com.google.errorprone.BugPattern",
-    "org.junit.jupiter.api.Test"
-  ]
-}

documentation-support/src/test/resources/tech/picnic/errorprone/documentation/bugpattern-documentation-minimal.json

@@ -1,14 +0,0 @@
-{
-  "fullyQualifiedName": "pkg.MinimalBugChecker",
-  "name": "MinimalBugChecker",
-  "altNames": [],
-  "link": "",
-  "tags": [],
-  "summary": "MinimalBugChecker summary",
-  "explanation": "",
-  "severityLevel": "ERROR",
-  "canDisable": true,
-  "suppressionAnnotations": [
-    "java.lang.SuppressWarnings"
-  ]
-}

documentation-support/src/test/resources/tech/picnic/errorprone/documentation/bugpattern-documentation-undocumented-suppression.json

@@ -1,12 +0,0 @@
-{
-  "fullyQualifiedName": "pkg.UndocumentedSuppressionBugPattern",
-  "name": "UndocumentedSuppressionBugPattern",
-  "altNames": [],
-  "link": "",
-  "tags": [],
-  "summary": "UndocumentedSuppressionBugPattern summary",
-  "explanation": "",
-  "severityLevel": "WARNING",
-  "canDisable": true,
-  "suppressionAnnotations": []
-}

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

@@ -5,13 +5,14 @@
     <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>
 
     <name>Picnic :: Error Prone Support :: Contrib</name>
     <description>Extra Error Prone plugins by Picnic.</description>
+    <url>https://error-prone.picnic.tech</url>
 
     <dependencies>
         <dependency>
@@ -47,6 +48,10 @@
             `annotationProcessorPaths` configuration below. -->
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>error-prone-utils</artifactId>
+        </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>refaster-support</artifactId>
@@ -60,11 +65,6 @@
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-annotations</artifactId>
-            <scope>test</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.google.auto</groupId>
-            <artifactId>auto-common</artifactId>
             <scope>provided</scope>
         </dependency>
         <dependency>
@@ -73,19 +73,15 @@
             <scope>provided</scope>
         </dependency>
         <dependency>
-            <groupId>com.google.googlejavaformat</groupId>
-            <artifactId>google-java-format</artifactId>
+            <groupId>com.google.auto.value</groupId>
+            <artifactId>auto-value-annotations</artifactId>
+            <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
             <scope>provided</scope>
         </dependency>
-        <dependency>
-            <groupId>com.newrelic.agent.java</groupId>
-            <artifactId>newrelic-api</artifactId>
-            <scope>test</scope>
-        </dependency>
         <dependency>
             <groupId>io.projectreactor</groupId>
             <artifactId>reactor-core</artifactId>
@@ -126,6 +122,11 @@
             <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>
@@ -156,6 +157,8 @@
             <artifactId>junit-jupiter-api</artifactId>
             <scope>provided</scope>
         </dependency>
+        <!-- XXX: Explicitly declared as a workaround for
+        https://github.com/pitest/pitest-junit5-plugin/issues/105. -->
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-engine</artifactId>
@@ -171,6 +174,36 @@
             <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.openrewrite</groupId>
+            <artifactId>rewrite-core</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openrewrite</groupId>
+            <artifactId>rewrite-java</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openrewrite</groupId>
+            <artifactId>rewrite-java-11</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openrewrite</groupId>
+            <artifactId>rewrite-templating</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.openrewrite</groupId>
+            <artifactId>rewrite-test</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.reactivestreams</groupId>
             <artifactId>reactive-streams</artifactId>
@@ -206,6 +239,11 @@
             <artifactId>spring-boot-test</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework.security</groupId>
+            <artifactId>spring-security-core</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.testng</groupId>
             <artifactId>testng</artifactId>
@@ -221,6 +259,9 @@
                     <artifactId>maven-compiler-plugin</artifactId>
                     <configuration>
                         <annotationProcessorPaths combine.children="append">
+                            <!-- XXX: Drop the version declarations once
+                            properly supported. See
+                            https://youtrack.jetbrains.com/issue/IDEA-342187. -->
                             <path>
                                 <groupId>${project.groupId}</groupId>
                                 <artifactId>documentation-support</artifactId>
@@ -243,17 +284,6 @@
                         </compilerArgs>
                     </configuration>
                 </plugin>
-                <plugin>
-                    <groupId>org.apache.maven.plugins</groupId>
-                    <artifactId>maven-dependency-plugin</artifactId>
-                    <configuration>
-                        <ignoredUnusedDeclaredDependencies>
-                            <!-- XXX: Figure out why the plugin thinks this
-                            dependency is unused. -->
-                            <ignoredUnusedDeclaredDependency>${project.groupId}:refaster-support</ignoredUnusedDeclaredDependency>
-                        </ignoredUnusedDeclaredDependencies>
-                    </configuration>
-                </plugin>
             </plugins>
         </pluginManagement>
     </build>

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

@@ -4,7 +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.LIKELY_ERROR;
 import static com.google.errorprone.matchers.Matchers.isType;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;

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

@@ -8,7 +8,7 @@ import static com.google.errorprone.matchers.Matchers.argument;
 import static com.google.errorprone.matchers.Matchers.argumentCount;
 import static com.google.errorprone.matchers.Matchers.instanceMethod;
 import static com.google.errorprone.matchers.Matchers.nullLiteral;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;

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

@@ -6,10 +6,9 @@ import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
 import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.isType;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 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;
@@ -17,13 +16,14 @@ 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.matchers.MultiMatcher.MultiMatchResult;
 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;
 import java.util.List;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /** A {@link BugChecker} that flags redundant {@code @Autowired} constructor annotations. */
 @AutoService(BugChecker.class)
@@ -48,11 +48,9 @@ public final class AutowiredConstructor extends BugChecker implements ClassTreeM
       return Description.NO_MATCH;
     }
 
-    ImmutableList<AnnotationTree> annotations =
-        AUTOWIRED_ANNOTATION
-            .multiMatchResult(Iterables.getOnlyElement(constructors), state)
-            .matchingNodes();
-    if (annotations.size() != 1) {
+    MultiMatchResult<AnnotationTree> hasAutowiredAnnotation =
+        AUTOWIRED_ANNOTATION.multiMatchResult(Iterables.getOnlyElement(constructors), state);
+    if (!hasAutowiredAnnotation.matches()) {
       return Description.NO_MATCH;
     }
 
@@ -61,7 +59,7 @@ public final class AutowiredConstructor extends BugChecker implements ClassTreeM
      * means that the associated import can be removed as well. Rather than adding code for this
      * case we leave flagging the unused import to Error Prone's `RemoveUnusedImports` check.
      */
-    AnnotationTree annotation = Iterables.getOnlyElement(annotations);
+    AnnotationTree annotation = hasAutowiredAnnotation.onlyMatchingNode();
     return describeMatch(annotation, SourceCode.deleteWithTrailingWhitespace(annotation, state));
   }
 }

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

@@ -3,7 +3,7 @@ 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.SIMPLIFICATION;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -26,7 +26,7 @@ import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /** A {@link BugChecker} that flags annotations that could be written more concisely. */
 @AutoService(BugChecker.class)
@@ -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/CanonicalClassNameUsage.java

@@ -0,0 +1,92 @@
+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.allOf;
+import static com.google.errorprone.matchers.Matchers.anything;
+import static com.google.errorprone.matchers.Matchers.classLiteral;
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+import static com.google.errorprone.matchers.Matchers.receiverOfInvocation;
+import static com.google.errorprone.matchers.Matchers.toType;
+import static tech.picnic.errorprone.utils.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.annotations.Var;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.BinaryTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.util.TreePath;
+import com.sun.tools.javac.code.Symbol.MethodSymbol;
+import java.util.regex.Pattern;
+
+/**
+ * A {@link BugChecker} that flags invocations of {@link Class#getName()} where {@link
+ * Class#getCanonicalName()} was likely meant.
+ *
+ * <p>For top-level types these two methods generally return the same result, but for nested types
+ * the former separates identifiers using a dollar sign ({@code $}) rather than a dot ({@code .}).
+ *
+ * @implNote This check currently only flags {@link Class#getName()} invocations on class literals,
+ *     and doesn't flag method references. This avoids false positives, such as suggesting use of
+ *     {@link Class#getCanonicalName()} in contexts where the canonical name is {@code null}.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "This code should likely use the type's canonical name",
+    link = BUG_PATTERNS_BASE_URL + "CanonicalClassNameUsage",
+    linkType = CUSTOM,
+    severity = WARNING,
+    tags = FRAGILE_CODE)
+public final class CanonicalClassNameUsage extends BugChecker
+    implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> GET_NAME_INVOCATION =
+      toType(
+          MethodInvocationTree.class,
+          allOf(
+              receiverOfInvocation(classLiteral(anything())),
+              instanceMethod().onExactClass(Class.class.getCanonicalName()).named("getName")));
+  private static final Pattern CANONICAL_NAME_USING_TYPES =
+      Pattern.compile("(com\\.google\\.errorprone|tech\\.picnic\\.errorprone)\\..*");
+
+  /** Instantiates a new {@link CanonicalClassNameUsage} instance. */
+  public CanonicalClassNameUsage() {}
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!GET_NAME_INVOCATION.matches(tree, state) || !isPassedToCanonicalNameUsingType(state)) {
+      /*
+       * This is not a `class.getName()` invocation of which the result is passed to another method
+       * known to accept canonical type names.
+       */
+      return Description.NO_MATCH;
+    }
+
+    return describeMatch(
+        tree, SuggestedFixes.renameMethodInvocation(tree, "getCanonicalName", state));
+  }
+
+  private static boolean isPassedToCanonicalNameUsingType(VisitorState state) {
+    @Var TreePath path = state.getPath().getParentPath();
+    while (path.getLeaf() instanceof BinaryTree) {
+      path = path.getParentPath();
+    }
+
+    return path.getLeaf() instanceof MethodInvocationTree
+        && isOwnedByCanonicalNameUsingType(
+            ASTHelpers.getSymbol((MethodInvocationTree) path.getLeaf()));
+  }
+
+  private static boolean isOwnedByCanonicalNameUsingType(MethodSymbol symbol) {
+    return CANONICAL_NAME_USING_TYPES.matcher(symbol.owner.getQualifiedName()).matches();
+  }
+}

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

@@ -4,9 +4,12 @@ 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.staticMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -17,8 +20,12 @@ import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.stream.Collector;
-import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;
+import java.util.stream.Collectors;
+import tech.picnic.errorprone.utils.ThirdPartyLibrary;
 
 /**
  * A {@link BugChecker} that flags {@link Collector Collectors} that don't clearly express
@@ -38,7 +45,7 @@ import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;
 public final class CollectorMutability extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> COLLECTOR_METHOD =
-      staticMethod().onClass("java.util.stream.Collectors");
+      staticMethod().onClass(Collectors.class.getCanonicalName());
   private static final Matcher<ExpressionTree> LIST_COLLECTOR =
       staticMethod().anyClass().named("toList");
   private static final Matcher<ExpressionTree> MAP_COLLECTOR =
@@ -58,7 +65,10 @@ public final class CollectorMutability extends BugChecker implements MethodInvoc
 
     if (LIST_COLLECTOR.matches(tree, state)) {
       return suggestToCollectionAlternatives(
-          tree, "com.google.common.collect.ImmutableList.toImmutableList", "ArrayList", state);
+          tree,
+          ImmutableList.class.getCanonicalName() + ".toImmutableList",
+          ArrayList.class.getCanonicalName(),
+          state);
     }
 
     if (MAP_COLLECTOR.matches(tree, state)) {
@@ -67,7 +77,10 @@ public final class CollectorMutability extends BugChecker implements MethodInvoc
 
     if (SET_COLLECTOR.matches(tree, state)) {
       return suggestToCollectionAlternatives(
-          tree, "com.google.common.collect.ImmutableSet.toImmutableSet", "HashSet", state);
+          tree,
+          ImmutableSet.class.getCanonicalName() + ".toImmutableSet",
+          HashSet.class.getCanonicalName(),
+          state);
     }
 
     return Description.NO_MATCH;
@@ -75,20 +88,20 @@ public final class CollectorMutability extends BugChecker implements MethodInvoc
 
   private Description suggestToCollectionAlternatives(
       MethodInvocationTree tree,
-      String fullyQualifiedImmutableReplacement,
+      String immutableReplacement,
       String mutableReplacement,
       VisitorState state) {
     SuggestedFix.Builder mutableFix = SuggestedFix.builder();
     String toCollectionSelect =
         SuggestedFixes.qualifyStaticImport(
-            "java.util.stream.Collectors.toCollection", mutableFix, state);
+            Collectors.class.getCanonicalName() + ".toCollection", mutableFix, state);
+    String mutableCollection = SuggestedFixes.qualifyType(state, mutableFix, mutableReplacement);
 
     return buildDescription(tree)
-        .addFix(replaceMethodInvocation(tree, fullyQualifiedImmutableReplacement, state))
+        .addFix(replaceMethodInvocation(tree, immutableReplacement, state))
         .addFix(
             mutableFix
-                .addImport(String.format("java.util.%s", mutableReplacement))
-                .replace(tree, String.format("%s(%s::new)", toCollectionSelect, mutableReplacement))
+                .replace(tree, String.format("%s(%s::new)", toCollectionSelect, mutableCollection))
                 .build())
         .build();
   }
@@ -99,17 +112,20 @@ public final class CollectorMutability extends BugChecker implements MethodInvoc
       return Description.NO_MATCH;
     }
 
+    SuggestedFix.Builder mutableFix = SuggestedFix.builder();
+    String hashMap =
+        SuggestedFixes.qualifyType(state, mutableFix, HashMap.class.getCanonicalName());
+
     return buildDescription(tree)
         .addFix(
             replaceMethodInvocation(
-                tree, "com.google.common.collect.ImmutableMap.toImmutableMap", state))
+                tree, ImmutableMap.class.getCanonicalName() + ".toImmutableMap", state))
         .addFix(
-            SuggestedFix.builder()
-                .addImport("java.util.HashMap")
+            mutableFix
                 .postfixWith(
                     tree.getArguments().get(argCount - 1),
                     (argCount == 2 ? ", (a, b) -> { throw new IllegalStateException(); }" : "")
-                        + ", HashMap::new")
+                        + String.format(", %s::new", hashMap))
                 .build())
         .build();
   }

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

@@ -11,7 +11,7 @@ import static com.google.errorprone.matchers.Matchers.not;
 import static com.google.errorprone.matchers.Matchers.returnStatement;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
 import static com.google.errorprone.matchers.Matchers.toType;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.Streams;
@@ -39,8 +39,8 @@ import com.sun.tools.javac.code.Symbol;
 import java.util.List;
 import java.util.Optional;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.bugpatterns.util.MoreASTHelpers;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.MoreASTHelpers;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags unnecessary local variable assignments preceding a return
@@ -58,7 +58,10 @@ public final class DirectReturn extends BugChecker implements BlockTreeMatcher {
   private static final Matcher<StatementTree> VARIABLE_RETURN = returnStatement(isVariable());
   private static final Matcher<ExpressionTree> MOCKITO_MOCK_OR_SPY_WITH_IMPLICIT_TYPE =
       allOf(
-          not(toType(MethodInvocationTree.class, argument(0, isSameType(Class.class.getName())))),
+          not(
+              toType(
+                  MethodInvocationTree.class,
+                  argument(0, isSameType(Class.class.getCanonicalName())))),
           staticMethod().onClass("org.mockito.Mockito").namedAnyOf("mock", "spy"));
 
   /** Instantiates a new {@link DirectReturn} instance. */

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

@@ -7,7 +7,7 @@ import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAS
 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 static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -21,7 +21,7 @@ import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.Tree;
 import java.util.Optional;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /** A {@link BugChecker} that flags empty methods that seemingly can simply be deleted. */
 @AutoService(BugChecker.class)
@@ -36,7 +36,9 @@ public final class EmptyMethod extends BugChecker implements MethodTreeMatcher {
   private static final Matcher<Tree> PERMITTED_ANNOTATION =
       annotations(
           AT_LEAST_ONE,
-          anyOf(isType("java.lang.Override"), isType("org.aspectj.lang.annotation.Pointcut")));
+          anyOf(
+              isType(Override.class.getCanonicalName()),
+              isType("org.aspectj.lang.annotation.Pointcut")));
 
   /** Instantiates a new {@link EmptyMethod} instance. */
   public EmptyMethod() {}

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

@@ -7,7 +7,7 @@ import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 import static java.util.stream.Collectors.collectingAndThen;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -44,7 +44,7 @@ import java.util.stream.Stream;
 public final class ExplicitEnumOrdering extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> EXPLICIT_ORDERING =
-      staticMethod().onClass(Ordering.class.getName()).named("explicit");
+      staticMethod().onClass(Ordering.class.getCanonicalName()).named("explicit");
 
   /** Instantiates a new {@link ExplicitEnumOrdering} instance. */
   public ExplicitEnumOrdering() {}
@@ -72,7 +72,7 @@ public final class ExplicitEnumOrdering extends BugChecker implements MethodInvo
       List<? extends ExpressionTree> expressions) {
     return expressions.stream()
         .map(ASTHelpers::getSymbol)
-        .filter(Symbol::isEnum)
+        .filter(s -> s != null && s.isEnum())
         .collect(
             collectingAndThen(
                 toImmutableSetMultimap(Symbol::asType, Symbol::toString),

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

@@ -4,11 +4,11 @@ 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.method.MethodMatchers.instanceMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-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 static tech.picnic.errorprone.bugpatterns.util.MoreTypes.unbound;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.MoreTypes.generic;
+import static tech.picnic.errorprone.utils.MoreTypes.subOf;
+import static tech.picnic.errorprone.utils.MoreTypes.type;
+import static tech.picnic.errorprone.utils.MoreTypes.unbound;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
@@ -66,7 +66,7 @@ public final class FluxFlatMapUsage extends BugChecker
       instanceMethod()
           .onDescendantOf(FLUX)
           .namedAnyOf("flatMap", "flatMapSequential")
-          .withParameters(Function.class.getName());
+          .withParameters(Function.class.getCanonicalName());
   private static final Supplier<Type> FLUX_OF_PUBLISHERS =
       VisitorState.memoize(
           generic(FLUX, subOf(generic(type("org.reactivestreams.Publisher"), unbound()))));

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

@@ -6,9 +6,10 @@ import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.BugPattern.StandardTags.CONCURRENCY;
 import static com.google.errorprone.BugPattern.StandardTags.PERFORMANCE;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -24,8 +25,9 @@ import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.tools.javac.code.Type;
 import com.sun.tools.javac.util.Position;
+import java.util.stream.Collectors;
 import java.util.stream.Stream;
-import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;
+import tech.picnic.errorprone.utils.ThirdPartyLibrary;
 
 /**
  * A {@link BugChecker} that flags {@link reactor.core.publisher.Flux} operator usages that may
@@ -48,7 +50,8 @@ public final class FluxImplicitBlock extends BugChecker implements MethodInvocat
           .onDescendantOf("reactor.core.publisher.Flux")
           .namedAnyOf("toIterable", "toStream")
           .withNoParameters();
-  private static final Supplier<Type> STREAM = Suppliers.typeFromString(Stream.class.getName());
+  private static final Supplier<Type> STREAM =
+      Suppliers.typeFromString(Stream.class.getCanonicalName());
 
   /** Instantiates a new {@link FluxImplicitBlock} instance. */
   public FluxImplicitBlock() {}
@@ -64,10 +67,11 @@ public final class FluxImplicitBlock extends BugChecker implements MethodInvocat
     if (ThirdPartyLibrary.GUAVA.isIntroductionAllowed(state)) {
       description.addFix(
           suggestBlockingElementCollection(
-              tree, "com.google.common.collect.ImmutableList.toImmutableList", state));
+              tree, ImmutableList.class.getCanonicalName() + ".toImmutableList", state));
     }
     description.addFix(
-        suggestBlockingElementCollection(tree, "java.util.stream.Collectors.toList", state));
+        suggestBlockingElementCollection(
+            tree, Collectors.class.getCanonicalName() + ".toList", state));
 
     return description.build();
   }

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

@@ -10,9 +10,11 @@ import static com.google.errorprone.matchers.Matchers.instanceMethod;
 import static com.google.errorprone.matchers.Matchers.not;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
 import static java.util.stream.Collectors.joining;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Verify;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -30,10 +32,11 @@ import com.sun.source.tree.Tree;
 import com.sun.source.tree.Tree.Kind;
 import com.sun.source.util.SimpleTreeVisitor;
 import java.util.ArrayList;
+import java.util.Formatter;
 import java.util.List;
 import java.util.Optional;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags string concatenations that produce a format string; in such cases
@@ -59,6 +62,7 @@ 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.
@@ -67,7 +71,8 @@ public final class FormatStringConcatenation extends BugChecker
       anyMethod()
           .anyClass()
           .withAnyName()
-          .withParameters(String.class.getName(), Throwable.class.getName());
+          .withParameters(String.class.getCanonicalName(), Throwable.class.getCanonicalName());
+
   // XXX: Drop some of these methods if we use Refaster to replace some with others.
   private static final Matcher<ExpressionTree> ASSERTJ_FORMAT_METHOD =
       anyOf(
@@ -116,14 +121,14 @@ public final class FormatStringConcatenation extends BugChecker
   private static final Matcher<ExpressionTree> GUAVA_FORMAT_METHOD =
       anyOf(
           staticMethod()
-              .onClass("com.google.common.base.Preconditions")
+              .onClass(Preconditions.class.getCanonicalName())
               .namedAnyOf("checkArgument", "checkNotNull", "checkState"),
-          staticMethod().onClass("com.google.common.base.Verify").named("verify"));
+          staticMethod().onClass(Verify.class.getCanonicalName()).named("verify"));
   // XXX: Add `PrintWriter`, maybe others.
   private static final Matcher<ExpressionTree> JDK_FORMAT_METHOD =
       anyOf(
-          staticMethod().onClass("java.lang.String").named("format"),
-          instanceMethod().onExactClass("java.util.Formatter").named("format"));
+          staticMethod().onClass(String.class.getCanonicalName()).named("format"),
+          instanceMethod().onExactClass(Formatter.class.getCanonicalName()).named("format"));
   private static final Matcher<ExpressionTree> SLF4J_FORMAT_METHOD =
       instanceMethod()
           .onDescendantOf("org.slf4j.Logger")

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

@@ -7,9 +7,20 @@ import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
 import static com.google.errorprone.suppliers.Suppliers.OBJECT_TYPE;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableBiMap;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableListMultimap;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMultimap;
+import com.google.common.collect.ImmutableMultiset;
+import com.google.common.collect.ImmutableRangeMap;
+import com.google.common.collect.ImmutableRangeSet;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableSetMultimap;
+import com.google.common.collect.ImmutableTable;
 import com.google.common.primitives.Primitives;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
@@ -20,6 +31,7 @@ import com.google.errorprone.fixes.SuggestedFix;
 import com.google.errorprone.fixes.SuggestedFixes;
 import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.matchers.Matchers;
 import com.google.errorprone.util.ASTHelpers;
 import com.google.errorprone.util.ASTHelpers.TargetType;
 import com.sun.source.tree.ExpressionTree;
@@ -29,7 +41,7 @@ import com.sun.tools.javac.code.Type;
 import com.sun.tools.javac.code.Types;
 import java.util.Arrays;
 import java.util.List;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /** A {@link BugChecker} that flags redundant identity conversions. */
 // XXX: Consider detecting cases where a flagged expression is passed to a method, and where removal
@@ -37,6 +49,8 @@ import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 // the target method such a modification may change the code's semantics or performance.
 // XXX: Also flag `Stream#map`, `Mono#map` and `Flux#map` invocations where the given transformation
 // is effectively the identity operation.
+// XXX: Also flag nullary instance method invocations that represent an identity conversion, such as
+// `Boolean#booleanValue()`, `Byte#byteValue()` and friends.
 @AutoService(BugChecker.class)
 @BugPattern(
     summary = "Avoid or clarify identity conversions",
@@ -54,24 +68,22 @@ public final class IdentityConversion extends BugChecker implements MethodInvoca
                       .map(Class::getName)
                       .collect(toImmutableSet()))
               .named("valueOf"),
-          staticMethod().onClass(String.class.getName()).named("valueOf"),
+          staticMethod().onClass(String.class.getCanonicalName()).named("valueOf"),
           staticMethod()
               .onClassAny(
-                  "com.google.common.collect.ImmutableBiMap",
-                  "com.google.common.collect.ImmutableList",
-                  "com.google.common.collect.ImmutableListMultimap",
-                  "com.google.common.collect.ImmutableMap",
-                  "com.google.common.collect.ImmutableMultimap",
-                  "com.google.common.collect.ImmutableMultiset",
-                  "com.google.common.collect.ImmutableRangeMap",
-                  "com.google.common.collect.ImmutableRangeSet",
-                  "com.google.common.collect.ImmutableSet",
-                  "com.google.common.collect.ImmutableSetMultimap",
-                  "com.google.common.collect.ImmutableTable")
+                  ImmutableBiMap.class.getCanonicalName(),
+                  ImmutableList.class.getCanonicalName(),
+                  ImmutableListMultimap.class.getCanonicalName(),
+                  ImmutableMap.class.getCanonicalName(),
+                  ImmutableMultimap.class.getCanonicalName(),
+                  ImmutableMultiset.class.getCanonicalName(),
+                  ImmutableRangeMap.class.getCanonicalName(),
+                  ImmutableRangeSet.class.getCanonicalName(),
+                  ImmutableSet.class.getCanonicalName(),
+                  ImmutableSetMultimap.class.getCanonicalName(),
+                  ImmutableTable.class.getCanonicalName())
               .named("copyOf"),
-          staticMethod()
-              .onClass("com.google.errorprone.matchers.Matchers")
-              .namedAnyOf("allOf", "anyOf"),
+          staticMethod().onClass(Matchers.class.getCanonicalName()).namedAnyOf("allOf", "anyOf"),
           staticMethod().onClass("reactor.adapter.rxjava.RxJava2Adapter"),
           staticMethod()
               .onClass("reactor.core.publisher.Flux")

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

@@ -11,7 +11,7 @@ import static com.google.errorprone.matchers.Matchers.hasModifier;
 import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
 import static com.google.errorprone.matchers.Matchers.methodReturns;
 import static com.google.errorprone.matchers.Matchers.not;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;

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

@@ -3,7 +3,7 @@ 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.SIMPLIFICATION;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
@@ -18,15 +18,14 @@ import com.sun.source.tree.InstanceOfTree;
 import com.sun.source.tree.LambdaExpressionTree;
 import com.sun.source.tree.Tree.Kind;
 import com.sun.source.tree.VariableTree;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags lambda expressions that can be replaced with a method reference
  * of the form {@code T.class::isInstance}.
- *
- * @see MethodReferenceUsage
  */
-// XXX: Consider folding this logic into the `MethodReferenceUsage` check.
+// XXX: Consider folding this logic into the `MethodReferenceUsage` check of the
+// `error-prone-experimental` module.
 @AutoService(BugChecker.class)
 @BugPattern(
     summary = "Prefer `Class::isInstance` method reference over equivalent lambda expression",

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

@@ -11,9 +11,9 @@ import static com.google.errorprone.matchers.Matchers.hasMethod;
 import static com.google.errorprone.matchers.Matchers.hasModifier;
 import static com.google.errorprone.matchers.Matchers.isType;
 import static com.google.errorprone.matchers.Matchers.not;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.TEST_METHOD;
-import static tech.picnic.errorprone.bugpatterns.util.MoreMatchers.hasMetaAnnotation;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.MoreJUnitMatchers.TEST_METHOD;
+import static tech.picnic.errorprone.utils.MoreMatchers.hasMetaAnnotation;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;

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

@@ -8,9 +8,9 @@ import static com.google.errorprone.matchers.Matchers.enclosingClass;
 import static com.google.errorprone.matchers.Matchers.hasModifier;
 import static com.google.errorprone.matchers.Matchers.not;
 import static java.util.function.Predicate.not;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.SETUP_OR_TEARDOWN_METHOD;
-import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.TEST_METHOD;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.MoreJUnitMatchers.SETUP_OR_TEARDOWN_METHOD;
+import static tech.picnic.errorprone.utils.MoreJUnitMatchers.TEST_METHOD;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -28,7 +28,7 @@ import com.sun.source.tree.MethodTree;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import java.util.Optional;
 import javax.lang.model.element.Modifier;
-import tech.picnic.errorprone.bugpatterns.util.ConflictDetection;
+import tech.picnic.errorprone.utils.ConflictDetection;
 
 /** A {@link BugChecker} that flags non-canonical JUnit method declarations. */
 // XXX: Consider introducing a class-level check that enforces that test classes:

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

@@ -0,0 +1,91 @@
+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.SIMPLIFICATION;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Matchers.annotations;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.isType;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.MoreMatchers.hasMetaAnnotation;
+
+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.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.matchers.MultiMatcher.MultiMatchResult;
+import com.sun.source.tree.AnnotationTree;
+import com.sun.source.tree.MethodTree;
+import tech.picnic.errorprone.utils.SourceCode;
+
+/**
+ * A {@link BugChecker} that flags nullary {@link
+ * org.junit.jupiter.params.ParameterizedTest @ParameterizedTest} test methods.
+ *
+ * <p>Such tests are unnecessarily executed more than necessary. This checker suggests annotating
+ * the method with {@link org.junit.jupiter.api.Test @Test}, and to drop all declared {@link
+ * org.junit.jupiter.params.provider.ArgumentsSource argument sources}.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Nullary JUnit test methods should not be parameterized",
+    link = BUG_PATTERNS_BASE_URL + "JUnitNullaryParameterizedTestDeclaration",
+    linkType = CUSTOM,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class JUnitNullaryParameterizedTestDeclaration extends BugChecker
+    implements MethodTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final MultiMatcher<MethodTree, AnnotationTree> IS_PARAMETERIZED_TEST =
+      annotations(AT_LEAST_ONE, isType("org.junit.jupiter.params.ParameterizedTest"));
+  private static final Matcher<AnnotationTree> IS_ARGUMENT_SOURCE =
+      anyOf(
+          isType("org.junit.jupiter.params.provider.ArgumentsSource"),
+          isType("org.junit.jupiter.params.provider.ArgumentsSources"),
+          hasMetaAnnotation("org.junit.jupiter.params.provider.ArgumentsSource"));
+
+  /** Instantiates a new {@link JUnitNullaryParameterizedTestDeclaration} instance. */
+  public JUnitNullaryParameterizedTestDeclaration() {}
+
+  @Override
+  public Description matchMethod(MethodTree tree, VisitorState state) {
+    if (!tree.getParameters().isEmpty()) {
+      return Description.NO_MATCH;
+    }
+
+    MultiMatchResult<AnnotationTree> isParameterizedTest =
+        IS_PARAMETERIZED_TEST.multiMatchResult(tree, state);
+    if (!isParameterizedTest.matches()) {
+      return Description.NO_MATCH;
+    }
+
+    /*
+     * This method is vacuously parameterized. Suggest replacing `@ParameterizedTest` with `@Test`.
+     * (As each method is checked independently, we cannot in general determine whether this
+     * suggestion makes a `ParameterizedTest` type import obsolete; that task is left to Error
+     * Prone's `RemoveUnusedImports` check.)
+     */
+    SuggestedFix.Builder fix = SuggestedFix.builder();
+    fix.merge(
+        SuggestedFix.replace(
+            isParameterizedTest.onlyMatchingNode(),
+            '@' + SuggestedFixes.qualifyType(state, fix, "org.junit.jupiter.api.Test")));
+
+    /*
+     * Also suggest dropping all (explicit and implicit) `@ArgumentsSource`s. No attempt is made to
+     * assess whether a dropped `@MethodSource` also makes the referenced factory method(s) unused.
+     */
+    tree.getModifiers().getAnnotations().stream()
+        .filter(a -> IS_ARGUMENT_SOURCE.matches(a, state))
+        .forEach(a -> fix.merge(SourceCode.deleteWithTrailingWhitespace(a, state)));
+
+    return describeMatch(tree, fix.build());
+  }
+}

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

@@ -19,17 +19,20 @@ import static com.google.errorprone.matchers.Matchers.staticMethod;
 import static com.google.errorprone.matchers.Matchers.toType;
 import static java.util.function.Predicate.not;
 import static java.util.stream.Collectors.joining;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.HAS_METHOD_SOURCE;
-import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.getMethodSourceFactoryNames;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.MoreJUnitMatchers.HAS_METHOD_SOURCE;
+import static tech.picnic.errorprone.utils.MoreJUnitMatchers.getMethodSourceFactoryNames;
 
 import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
 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.util.ASTHelpers;
@@ -55,7 +58,7 @@ import java.util.stream.IntStream;
 import java.util.stream.LongStream;
 import java.util.stream.Stream;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags JUnit tests with a {@link
@@ -99,14 +102,14 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
           allOf(
               staticMethod()
                   .onClassAny(
-                      Stream.class.getName(),
-                      IntStream.class.getName(),
-                      LongStream.class.getName(),
-                      DoubleStream.class.getName(),
-                      List.class.getName(),
-                      Set.class.getName(),
-                      "com.google.common.collect.ImmutableList",
-                      "com.google.common.collect.ImmutableSet")
+                      Stream.class.getCanonicalName(),
+                      IntStream.class.getCanonicalName(),
+                      LongStream.class.getCanonicalName(),
+                      DoubleStream.class.getCanonicalName(),
+                      List.class.getCanonicalName(),
+                      Set.class.getCanonicalName(),
+                      ImmutableList.class.getCanonicalName(),
+                      ImmutableSet.class.getCanonicalName())
                   .named("of"),
               hasArguments(AT_LEAST_ONE, anything()),
               hasArguments(ALL, SUPPORTED_VALUE_FACTORY_VALUES)));
@@ -199,16 +202,21 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
     return getSingleReturnExpression(valueFactoryMethod)
         .flatMap(expression -> tryExtractValueSourceAttributeValue(expression, state))
         .map(
-            valueSourceAttributeValue ->
-                SuggestedFix.builder()
-                    .addImport("org.junit.jupiter.params.provider.ValueSource")
-                    .replace(
-                        methodSourceAnnotation,
-                        String.format(
-                            "@ValueSource(%s = %s)",
-                            toValueSourceAttributeName(parameterType), valueSourceAttributeValue))
-                    .delete(valueFactoryMethod)
-                    .build());
+            valueSourceAttributeValue -> {
+              SuggestedFix.Builder fix = SuggestedFix.builder();
+              String valueSource =
+                  SuggestedFixes.qualifyType(
+                      state, fix, "org.junit.jupiter.params.provider.ValueSource");
+              return fix.replace(
+                      methodSourceAnnotation,
+                      String.format(
+                          "@%s(%s = %s)",
+                          valueSource,
+                          toValueSourceAttributeName(parameterType),
+                          valueSourceAttributeValue))
+                  .delete(valueFactoryMethod)
+                  .build();
+            });
   }
 
   // XXX: This pattern also occurs a few times inside Error Prone; contribute upstream.

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

@@ -7,7 +7,7 @@ import static com.google.errorprone.BugPattern.StandardTags.STYLE;
 import static java.util.Comparator.comparing;
 import static java.util.Comparator.naturalOrder;
 import static java.util.stream.Collectors.joining;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
@@ -40,10 +40,11 @@ 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;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.utils.Flags;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags annotation array listings which aren't sorted lexicographically.
@@ -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

@@ -7,7 +7,7 @@ import static com.google.errorprone.BugPattern.StandardTags.STYLE;
 import static com.sun.tools.javac.code.TypeAnnotations.AnnotationType.DECLARATION;
 import static com.sun.tools.javac.code.TypeAnnotations.AnnotationType.TYPE;
 import static java.util.Comparator.comparing;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
@@ -28,7 +28,7 @@ import com.sun.tools.javac.code.TypeAnnotations.AnnotationType;
 import java.util.Comparator;
 import java.util.List;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags annotations that are not lexicographically sorted.
@@ -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/MockitoMockClassReference.java

@@ -9,7 +9,7 @@ import static com.google.errorprone.matchers.Matchers.isSameType;
 import static com.google.errorprone.matchers.Matchers.isVariable;
 import static com.google.errorprone.matchers.Matchers.not;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -25,7 +25,7 @@ import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.Tree;
 import com.sun.source.tree.VariableTree;
 import java.util.List;
-import tech.picnic.errorprone.bugpatterns.util.MoreASTHelpers;
+import tech.picnic.errorprone.utils.MoreASTHelpers;
 
 /**
  * A {@link BugChecker} that flags the use of {@link org.mockito.Mockito#mock(Class)} and {@link
@@ -50,7 +50,7 @@ public final class MockitoMockClassReference extends BugChecker
   private static final long serialVersionUID = 1L;
   private static final Matcher<MethodInvocationTree> MOCKITO_MOCK_OR_SPY_WITH_HARDCODED_TYPE =
       allOf(
-          argument(0, allOf(isSameType(Class.class.getName()), not(isVariable()))),
+          argument(0, allOf(isSameType(Class.class.getCanonicalName()), not(isVariable()))),
           staticMethod().onClass("org.mockito.Mockito").namedAnyOf("mock", "spy"));
 
   /** Instantiates a new {@link MockitoMockClassReference} instance. */
@@ -71,7 +71,7 @@ public final class MockitoMockClassReference extends BugChecker
     Tree parent = state.getPath().getParentPath().getLeaf();
     switch (parent.getKind()) {
       case VARIABLE:
-        return !ASTHelpers.hasNoExplicitType((VariableTree) parent, state)
+        return !ASTHelpers.hasImplicitType((VariableTree) parent, state)
             && MoreASTHelpers.areSameType(tree, parent, state);
       case ASSIGNMENT:
         return MoreASTHelpers.areSameType(tree, parent, state);

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

@@ -4,7 +4,7 @@ import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
 import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
 import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
@@ -18,7 +18,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
 import java.util.List;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags method invocations for which all arguments are wrapped using

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.utils.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

@@ -3,10 +3,11 @@ 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 tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.MoreMatchers.isSubTypeOf;
+import static tech.picnic.errorprone.utils.MoreTypes.generic;
+import static tech.picnic.errorprone.utils.MoreTypes.raw;
+import static tech.picnic.errorprone.utils.MoreTypes.subOf;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.MoreTypePredicates.hasTypeParameter;
+import static tech.picnic.errorprone.utils.MoreTypePredicates.isSubTypeOf;
+import static tech.picnic.errorprone.utils.MoreTypes.generic;
+import static tech.picnic.errorprone.utils.MoreTypes.raw;
+import static tech.picnic.errorprone.utils.MoreTypes.subOf;
+import static tech.picnic.errorprone.utils.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/NonEmptyMono.java

@@ -5,7 +5,7 @@ import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -20,7 +20,7 @@ import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
 import java.util.function.BiFunction;
 import reactor.core.publisher.Mono;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags {@link Mono} operations that are known to be vacuous, given that
@@ -72,7 +72,7 @@ public final class NonEmptyMono extends BugChecker implements MethodInvocationTr
           instanceMethod()
               .onDescendantOf("reactor.core.publisher.Flux")
               .named("reduce")
-              .withParameters(Object.class.getName(), BiFunction.class.getName()),
+              .withParameters(Object.class.getCanonicalName(), BiFunction.class.getCanonicalName()),
           instanceMethod()
               .onDescendantOf("reactor.core.publisher.Mono")
               .namedAnyOf("defaultIfEmpty", "hasElement", "single"));

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

@@ -0,0 +1,225 @@
+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.STYLE;
+import static tech.picnic.errorprone.bugpatterns.StaticImport.STATIC_IMPORT_CANDIDATE_MEMBERS;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+
+import com.google.auto.service.AutoService;
+import com.google.auto.value.AutoValue;
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Predicates;
+import com.google.common.base.Strings;
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.ImmutableSetMultimap;
+import com.google.common.collect.ImmutableTable;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.CompilationUnitTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.CompilationUnitTree;
+import com.sun.source.tree.IdentifierTree;
+import com.sun.source.tree.ImportTree;
+import com.sun.source.tree.MemberSelectTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.util.TreeScanner;
+import com.sun.tools.javac.code.Symbol;
+import java.time.Clock;
+import java.time.ZoneOffset;
+import java.util.Collections;
+import java.util.Locale;
+import java.util.Optional;
+import java.util.regex.Pattern;
+import org.jspecify.annotations.Nullable;
+import tech.picnic.errorprone.utils.SourceCode;
+
+/**
+ * A {@link BugChecker} that flags static imports of type members that should *not* be statically
+ * imported.
+ */
+// XXX: This check is closely linked to `StaticImport`. Consider merging the two.
+// XXX: Add suppression support. If qualification of one more more identifiers is suppressed, then
+// the associated static import should *not* be removed.
+// XXX: Also introduce logic that disallows statically importing `ZoneOffset.ofHours` and other
+// `ofXXX`-style methods.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Member should not be statically imported",
+    link = BUG_PATTERNS_BASE_URL + "NonStaticImport",
+    linkType = CUSTOM,
+    severity = SUGGESTION,
+    tags = STYLE)
+public final class NonStaticImport extends BugChecker implements CompilationUnitTreeMatcher {
+  private static final long serialVersionUID = 1L;
+
+  /**
+   * Types whose members should not be statically imported, unless exempted by {@link
+   * StaticImport#STATIC_IMPORT_CANDIDATE_MEMBERS}.
+   *
+   * <p>Types listed here should be mutually exclusive with {@link
+   * StaticImport#STATIC_IMPORT_CANDIDATE_TYPES}.
+   */
+  @VisibleForTesting
+  static final ImmutableSet<String> NON_STATIC_IMPORT_CANDIDATE_TYPES =
+      ImmutableSet.of(
+          ASTHelpers.class.getCanonicalName(),
+          Clock.class.getCanonicalName(),
+          Strings.class.getCanonicalName(),
+          VisitorState.class.getCanonicalName(),
+          ZoneOffset.class.getCanonicalName(),
+          "com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode",
+          "reactor.core.publisher.Flux",
+          "reactor.core.publisher.Mono");
+
+  /**
+   * Type members that should never be statically imported.
+   *
+   * <p>Please note that:
+   *
+   * <ul>
+   *   <li>Types listed by {@link #NON_STATIC_IMPORT_CANDIDATE_TYPES} and members listed by {@link
+   *       #NON_STATIC_IMPORT_CANDIDATE_IDENTIFIERS} should be omitted from this collection.
+   *   <li>This collection should be mutually exclusive with {@link
+   *       StaticImport#STATIC_IMPORT_CANDIDATE_MEMBERS}.
+   * </ul>
+   */
+  // XXX: Perhaps the set of exempted `java.util.Collections` methods is too strict. For now any
+  // method name that could be considered "too vague" or could conceivably mean something else in a
+  // specific context is left out.
+  static final ImmutableSetMultimap<String, String> NON_STATIC_IMPORT_CANDIDATE_MEMBERS =
+      ImmutableSetMultimap.<String, String>builder()
+          .putAll(
+              Collections.class.getCanonicalName(),
+              "addAll",
+              "copy",
+              "fill",
+              "list",
+              "max",
+              "min",
+              "nCopies",
+              "rotate",
+              "sort",
+              "swap")
+          .put(Locale.class.getCanonicalName(), "ROOT")
+          .put(Optional.class.getCanonicalName(), "empty")
+          .putAll(Pattern.class.getCanonicalName(), "compile", "matches", "quote")
+          .put(Predicates.class.getCanonicalName(), "contains")
+          .put("org.springframework.http.MediaType", "ALL")
+          .build();
+
+  /**
+   * Identifiers that should never be statically imported.
+   *
+   * <p>Please note that:
+   *
+   * <ul>
+   *   <li>Identifiers listed by {@link StaticImport#STATIC_IMPORT_CANDIDATE_MEMBERS} should be
+   *       mutually exclusive with identifiers listed here.
+   *   <li>This list should contain a superset of the identifiers flagged by {@link
+   *       com.google.errorprone.bugpatterns.BadImport}.
+   * </ul>
+   */
+  static final ImmutableSet<String> NON_STATIC_IMPORT_CANDIDATE_IDENTIFIERS =
+      ImmutableSet.of(
+          "builder",
+          "copyOf",
+          "create",
+          "from",
+          "getDefaultInstance",
+          "INSTANCE",
+          "MAX",
+          "MAX_VALUE",
+          "MIN",
+          "MIN_VALUE",
+          "newBuilder",
+          "newInstance",
+          "of",
+          "parse",
+          "valueOf");
+
+  /** Instantiates a new {@link NonStaticImport} instance. */
+  public NonStaticImport() {}
+
+  @Override
+  public Description matchCompilationUnit(CompilationUnitTree tree, VisitorState state) {
+    ImmutableTable<String, String, UndesiredStaticImport> undesiredStaticImports =
+        getUndesiredStaticImports(tree, state);
+
+    if (!undesiredStaticImports.isEmpty()) {
+      replaceUndesiredStaticImportUsages(tree, undesiredStaticImports, state);
+
+      for (UndesiredStaticImport staticImport : undesiredStaticImports.values()) {
+        state.reportMatch(
+            describeMatch(staticImport.importTree(), staticImport.fixBuilder().build()));
+      }
+    }
+
+    /* Any violations have been flagged against the offending static import statement. */
+    return Description.NO_MATCH;
+  }
+
+  private static ImmutableTable<String, String, UndesiredStaticImport> getUndesiredStaticImports(
+      CompilationUnitTree tree, VisitorState state) {
+    ImmutableTable.Builder<String, String, UndesiredStaticImport> imports =
+        ImmutableTable.builder();
+    for (ImportTree importTree : tree.getImports()) {
+      Tree qualifiedIdentifier = importTree.getQualifiedIdentifier();
+      if (importTree.isStatic() && qualifiedIdentifier instanceof MemberSelectTree) {
+        MemberSelectTree memberSelectTree = (MemberSelectTree) qualifiedIdentifier;
+        String type = SourceCode.treeToString(memberSelectTree.getExpression(), state);
+        String member = memberSelectTree.getIdentifier().toString();
+        if (shouldNotBeStaticallyImported(type, member)) {
+          imports.put(
+              type,
+              member,
+              new AutoValue_NonStaticImport_UndesiredStaticImport(
+                  importTree, SuggestedFix.builder().removeStaticImport(type + '.' + member)));
+        }
+      }
+    }
+
+    return imports.build();
+  }
+
+  private static boolean shouldNotBeStaticallyImported(String type, String member) {
+    return (NON_STATIC_IMPORT_CANDIDATE_TYPES.contains(type)
+            && !STATIC_IMPORT_CANDIDATE_MEMBERS.containsEntry(type, member))
+        || NON_STATIC_IMPORT_CANDIDATE_MEMBERS.containsEntry(type, member)
+        || NON_STATIC_IMPORT_CANDIDATE_IDENTIFIERS.contains(member);
+  }
+
+  private static void replaceUndesiredStaticImportUsages(
+      CompilationUnitTree tree,
+      ImmutableTable<String, String, UndesiredStaticImport> undesiredStaticImports,
+      VisitorState state) {
+    new TreeScanner<@Nullable Void, @Nullable Void>() {
+      @Override
+      public @Nullable Void visitIdentifier(IdentifierTree node, @Nullable Void unused) {
+        Symbol symbol = ASTHelpers.getSymbol(node);
+        if (symbol != null) {
+          UndesiredStaticImport staticImport =
+              undesiredStaticImports.get(
+                  symbol.owner.getQualifiedName().toString(), symbol.name.toString());
+          if (staticImport != null) {
+            SuggestedFix.Builder fix = staticImport.fixBuilder();
+            fix.prefixWith(node, SuggestedFixes.qualifyType(state, fix, symbol.owner) + '.');
+          }
+        }
+
+        return super.visitIdentifier(node, unused);
+      }
+    }.scan(tree, null);
+  }
+
+  @AutoValue
+  abstract static class UndesiredStaticImport {
+    abstract ImportTree importTree();
+
+    abstract SuggestedFix.Builder fixBuilder();
+  }
+}

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

@@ -7,7 +7,7 @@ import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 import static java.util.stream.Collectors.joining;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
@@ -17,6 +17,7 @@ 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.fixes.SuggestedFixes;
 import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.util.ASTHelpers;
@@ -32,7 +33,7 @@ import java.util.Comparator;
 import java.util.Optional;
 import java.util.function.Function;
 import java.util.stream.Stream;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags {@code Comparator#comparing*} invocations that can be replaced
@@ -55,21 +56,21 @@ public final class PrimitiveComparison extends BugChecker implements MethodInvoc
   private static final Matcher<ExpressionTree> STATIC_COMPARISON_METHOD =
       anyOf(
           staticMethod()
-              .onClass(Comparator.class.getName())
+              .onClass(Comparator.class.getCanonicalName())
               .namedAnyOf("comparingInt", "comparingLong", "comparingDouble"),
           staticMethod()
-              .onClass(Comparator.class.getName())
+              .onClass(Comparator.class.getCanonicalName())
               .named("comparing")
-              .withParameters(Function.class.getName()));
+              .withParameters(Function.class.getCanonicalName()));
   private static final Matcher<ExpressionTree> INSTANCE_COMPARISON_METHOD =
       anyOf(
           instanceMethod()
-              .onDescendantOf(Comparator.class.getName())
+              .onDescendantOf(Comparator.class.getCanonicalName())
               .namedAnyOf("thenComparingInt", "thenComparingLong", "thenComparingDouble"),
           instanceMethod()
-              .onDescendantOf(Comparator.class.getName())
+              .onDescendantOf(Comparator.class.getCanonicalName())
               .named("thenComparing")
-              .withParameters(Function.class.getName()));
+              .withParameters(Function.class.getCanonicalName()));
 
   /** Instantiates a new {@link PrimitiveComparison} instance. */
   public PrimitiveComparison() {}
@@ -167,10 +168,11 @@ public final class PrimitiveComparison extends BugChecker implements MethodInvoc
     ExpressionTree expr = tree.getMethodSelect();
     switch (expr.getKind()) {
       case IDENTIFIER:
-        return SuggestedFix.builder()
-            .addStaticImport(Comparator.class.getName() + '.' + preferredMethodName)
-            .replace(expr, preferredMethodName)
-            .build();
+        SuggestedFix.Builder fix = SuggestedFix.builder();
+        String replacement =
+            SuggestedFixes.qualifyStaticImport(
+                Comparator.class.getCanonicalName() + '.' + preferredMethodName, fix, state);
+        return fix.replace(expr, replacement).build();
       case MEMBER_SELECT:
         MemberSelectTree ms = (MemberSelectTree) tree.getMethodSelect();
         return SuggestedFix.replace(

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

@@ -15,9 +15,11 @@ import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
 import static com.google.errorprone.matchers.Matchers.not;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Verify;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.common.primitives.Primitives;
@@ -50,9 +52,10 @@ import java.util.Locale;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.stream.Stream;
-import tech.picnic.errorprone.bugpatterns.util.Flags;
-import tech.picnic.errorprone.bugpatterns.util.MethodMatcherFactory;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import javax.inject.Inject;
+import tech.picnic.errorprone.utils.Flags;
+import tech.picnic.errorprone.utils.MethodMatcherFactory;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /** A {@link BugChecker} that flags redundant explicit string conversions. */
 @AutoService(BugChecker.class)
@@ -85,7 +88,7 @@ public final class RedundantStringConversion extends BugChecker
   private static final Matcher<MethodInvocationTree> WELL_KNOWN_STRING_CONVERSION_METHODS =
       anyOf(
           instanceMethod()
-              .onDescendantOfAny(Object.class.getName())
+              .onDescendantOfAny(Object.class.getCanonicalName())
               .named("toString")
               .withNoParameters(),
           allOf(
@@ -99,7 +102,7 @@ public final class RedundantStringConversion extends BugChecker
                               .collect(toImmutableSet()))
                       .named("toString"),
                   allOf(
-                      staticMethod().onClass(String.class.getName()).named("valueOf"),
+                      staticMethod().onClass(String.class.getCanonicalName()).named("valueOf"),
                       not(
                           anyMethod()
                               .anyClass()
@@ -108,35 +111,37 @@ public final class RedundantStringConversion extends BugChecker
                                   ImmutableList.of(Suppliers.arrayOf(Suppliers.CHAR_TYPE))))))));
   private static final Matcher<ExpressionTree> STRINGBUILDER_APPEND_INVOCATION =
       instanceMethod()
-          .onDescendantOf(StringBuilder.class.getName())
+          .onDescendantOf(StringBuilder.class.getCanonicalName())
           .named("append")
-          .withParameters(String.class.getName());
+          .withParameters(String.class.getCanonicalName());
   private static final Matcher<ExpressionTree> STRINGBUILDER_INSERT_INVOCATION =
       instanceMethod()
-          .onDescendantOf(StringBuilder.class.getName())
+          .onDescendantOf(StringBuilder.class.getCanonicalName())
           .named("insert")
-          .withParameters(int.class.getName(), String.class.getName());
+          .withParameters(int.class.getCanonicalName(), String.class.getCanonicalName());
   private static final Matcher<ExpressionTree> FORMATTER_INVOCATION =
       anyOf(
-          staticMethod().onClass(String.class.getName()).named("format"),
-          instanceMethod().onDescendantOf(Formatter.class.getName()).named("format"),
+          staticMethod().onClass(String.class.getCanonicalName()).named("format"),
+          instanceMethod().onDescendantOf(Formatter.class.getCanonicalName()).named("format"),
           instanceMethod()
-              .onDescendantOfAny(PrintStream.class.getName(), PrintWriter.class.getName())
+              .onDescendantOfAny(
+                  PrintStream.class.getCanonicalName(), PrintWriter.class.getCanonicalName())
               .namedAnyOf("format", "printf"),
           instanceMethod()
-              .onDescendantOfAny(PrintStream.class.getName(), PrintWriter.class.getName())
+              .onDescendantOfAny(
+                  PrintStream.class.getCanonicalName(), PrintWriter.class.getCanonicalName())
               .namedAnyOf("print", "println")
-              .withParameters(Object.class.getName()),
+              .withParameters(Object.class.getCanonicalName()),
           staticMethod()
-              .onClass(Console.class.getName())
+              .onClass(Console.class.getCanonicalName())
               .namedAnyOf("format", "printf", "readline", "readPassword"));
   private static final Matcher<ExpressionTree> GUAVA_GUARD_INVOCATION =
       anyOf(
           staticMethod()
-              .onClass("com.google.common.base.Preconditions")
+              .onClass(Preconditions.class.getCanonicalName())
               .namedAnyOf("checkArgument", "checkState", "checkNotNull"),
           staticMethod()
-              .onClass("com.google.common.base.Verify")
+              .onClass(Verify.class.getCanonicalName())
               .namedAnyOf("verify", "verifyNotNull"));
   private static final Matcher<ExpressionTree> SLF4J_LOGGER_INVOCATION =
       instanceMethod()
@@ -155,7 +160,8 @@ 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/RequestMappingAnnotation.java

@@ -11,7 +11,7 @@ import static com.google.errorprone.matchers.Matchers.isSameType;
 import static com.google.errorprone.matchers.Matchers.isType;
 import static com.google.errorprone.matchers.Matchers.methodHasParameters;
 import static com.google.errorprone.matchers.Matchers.not;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -22,6 +22,10 @@ import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.Tree;
+import java.io.InputStream;
+import java.time.ZoneId;
+import java.util.Locale;
+import java.util.TimeZone;
 
 /**
  * A {@link BugChecker} that flags {@code @RequestMapping} methods that have one or more parameters
@@ -69,11 +73,13 @@ public final class RequestMappingAnnotation extends BugChecker implements Method
                           isType(ANN_PACKAGE_PREFIX + "RequestBody"),
                           isType(ANN_PACKAGE_PREFIX + "RequestHeader"),
                           isType(ANN_PACKAGE_PREFIX + "RequestParam"),
-                          isType(ANN_PACKAGE_PREFIX + "RequestPart"))),
-                  isSameType("java.io.InputStream"),
-                  isSameType("java.time.ZoneId"),
-                  isSameType("java.util.Locale"),
-                  isSameType("java.util.TimeZone"),
+                          isType(ANN_PACKAGE_PREFIX + "RequestPart"),
+                          isType(
+                              "org.springframework.security.core.annotation.CurrentSecurityContext"))),
+                  isSameType(InputStream.class.getCanonicalName()),
+                  isSameType(Locale.class.getCanonicalName()),
+                  isSameType(TimeZone.class.getCanonicalName()),
+                  isSameType(ZoneId.class.getCanonicalName()),
                   isSameType("jakarta.servlet.http.HttpServletRequest"),
                   isSameType("jakarta.servlet.http.HttpServletResponse"),
                   isSameType("javax.servlet.http.HttpServletRequest"),

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

@@ -11,7 +11,7 @@ import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
 import static com.google.errorprone.matchers.Matchers.isType;
 import static com.google.errorprone.matchers.Matchers.not;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableCollection;
@@ -27,7 +27,8 @@ 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 tech.picnic.errorprone.bugpatterns.util.Flags;
+import javax.inject.Inject;
+import tech.picnic.errorprone.utils.Flags;
 
 /** A {@link BugChecker} that flags {@code @RequestParam} parameters with an unsupported type. */
 @AutoService(BugChecker.class)
@@ -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/Slf4jLogStatement.java

@@ -6,7 +6,7 @@ import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
 import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
@@ -23,7 +23,7 @@ import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.Tree.Kind;
 import java.util.List;
 import java.util.Optional;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /** A {@link BugChecker} that flags SLF4J usages that are likely to be in error. */
 // XXX: The special-casing of Throwable applies only to SLF4J 1.6.0+; see

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

@@ -6,7 +6,7 @@ import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
 import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static java.util.function.Predicate.not;
 import static java.util.stream.Collectors.joining;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
@@ -18,6 +18,7 @@ import com.google.errorprone.bugpatterns.BugChecker;
 import com.google.errorprone.bugpatterns.BugChecker.AnnotationTreeMatcher;
 import com.google.errorprone.fixes.Fix;
 import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
 import com.google.errorprone.matchers.Description;
 import com.sun.source.tree.AnnotationTree;
 import com.sun.source.tree.AssignmentTree;
@@ -26,8 +27,8 @@ import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.NewArrayTree;
 import com.sun.source.tree.Tree.Kind;
 import java.util.Optional;
-import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags {@code @RequestMapping} annotations that can be written more
@@ -114,9 +115,8 @@ public final class SpringMvcAnnotation extends BugChecker implements AnnotationT
             .map(arg -> SourceCode.treeToString(arg, state))
             .collect(joining(", "));
 
-    return SuggestedFix.builder()
-        .addImport(ANN_PACKAGE_PREFIX + newAnnotation)
-        .replace(tree, String.format("@%s(%s)", newAnnotation, newArguments))
-        .build();
+    SuggestedFix.Builder fix = SuggestedFix.builder();
+    String annotation = SuggestedFixes.qualifyType(state, fix, ANN_PACKAGE_PREFIX + newAnnotation);
+    return fix.replace(tree, String.format("@%s(%s)", annotation, newArguments)).build();
   }
 }

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

@@ -2,14 +2,32 @@ 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.SIMPLIFICATION;
+import static com.google.errorprone.BugPattern.StandardTags.STYLE;
 import static java.util.Objects.requireNonNull;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.NonStaticImport.NON_STATIC_IMPORT_CANDIDATE_IDENTIFIERS;
+import static tech.picnic.errorprone.bugpatterns.NonStaticImport.NON_STATIC_IMPORT_CANDIDATE_MEMBERS;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Functions;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Predicates;
+import com.google.common.base.Verify;
+import com.google.common.collect.Comparators;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableListMultimap;
+import com.google.common.collect.ImmutableMap;
+import com.google.common.collect.ImmutableMultiset;
+import com.google.common.collect.ImmutableRangeSet;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSetMultimap;
+import com.google.common.collect.ImmutableSortedMap;
+import com.google.common.collect.ImmutableSortedMultiset;
+import com.google.common.collect.ImmutableSortedSet;
+import com.google.common.collect.ImmutableTable;
+import com.google.common.collect.MoreCollectors;
+import com.google.common.collect.Sets;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -20,55 +38,73 @@ import com.google.errorprone.fixes.Fix;
 import com.google.errorprone.fixes.SuggestedFix;
 import com.google.errorprone.fixes.SuggestedFixes;
 import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matchers;
+import com.google.errorprone.refaster.ImportPolicy;
 import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.Tree;
 import com.sun.tools.javac.code.Type;
+import java.nio.charset.StandardCharsets;
+import java.time.ZoneOffset;
+import java.util.Collections;
+import java.util.Comparator;
+import java.util.Map;
+import java.util.Objects;
 import java.util.Optional;
+import java.util.UUID;
+import java.util.function.Function;
+import java.util.function.Predicate;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
 
-/**
- * A {@link BugChecker} that flags methods and constants that can and should be statically imported.
- */
+/** A {@link BugChecker} that flags type members that can and should be statically imported. */
+// XXX: This check is closely linked to `NonStaticImport`. Consider merging the two.
 // XXX: Tricky cases:
 // - `org.springframework.http.HttpStatus` (not always an improvement, and `valueOf` must
 //    certainly be excluded)
 // - `com.google.common.collect.Tables`
-// - `ch.qos.logback.classic.Level.{DEBUG, ERROR, INFO, TRACE, WARN"}`
-// XXX: Also introduce a check that disallows static imports of certain methods. Candidates:
-// - `com.google.common.base.Strings`
-// - `java.util.Optional.empty`
-// - `java.util.Locale.ROOT`
-// - `ZoneOffset.ofHours` and other `ofXXX`-style methods.
-// - `java.time.Clock`.
-// - Several other `java.time` classes.
-// - Likely any of `*.{ZERO, ONE, MIX, MAX, MIN_VALUE, MAX_VALUE}`.
+// - `ch.qos.logback.classic.Level.{DEBUG, ERROR, INFO, TRACE, WARN}`
 @AutoService(BugChecker.class)
 @BugPattern(
     summary = "Identifier should be statically imported",
     link = BUG_PATTERNS_BASE_URL + "StaticImport",
     linkType = CUSTOM,
     severity = SUGGESTION,
-    tags = SIMPLIFICATION)
+    tags = STYLE)
 public final class StaticImport extends BugChecker implements MemberSelectTreeMatcher {
   private static final long serialVersionUID = 1L;
 
   /**
    * Types whose members should be statically imported, unless exempted by {@link
-   * #STATIC_IMPORT_EXEMPTED_MEMBERS} or {@link #STATIC_IMPORT_EXEMPTED_IDENTIFIERS}.
+   * NonStaticImport#NON_STATIC_IMPORT_CANDIDATE_MEMBERS} or {@link
+   * NonStaticImport#NON_STATIC_IMPORT_CANDIDATE_IDENTIFIERS}.
+   *
+   * <p>Types listed here should be mutually exclusive with {@link
+   * NonStaticImport#NON_STATIC_IMPORT_CANDIDATE_TYPES}.
    */
   @VisibleForTesting
   static final ImmutableSet<String> STATIC_IMPORT_CANDIDATE_TYPES =
       ImmutableSet.of(
-          "com.google.common.base.Preconditions",
-          "com.google.common.base.Predicates",
-          "com.google.common.base.Verify",
-          "com.google.common.collect.MoreCollectors",
-          "com.google.errorprone.BugPattern.LinkType",
-          "com.google.errorprone.BugPattern.SeverityLevel",
-          "com.google.errorprone.BugPattern.StandardTags",
-          "com.google.errorprone.matchers.Matchers",
-          "com.google.errorprone.refaster.ImportPolicy",
+          BugPattern.LinkType.class.getCanonicalName(),
+          BugPattern.SeverityLevel.class.getCanonicalName(),
+          BugPattern.StandardTags.class.getCanonicalName(),
+          Collections.class.getCanonicalName(),
+          Collectors.class.getCanonicalName(),
+          Comparator.class.getCanonicalName(),
+          ImportPolicy.class.getCanonicalName(),
+          Map.Entry.class.getCanonicalName(),
+          Matchers.class.getCanonicalName(),
+          MoreCollectors.class.getCanonicalName(),
+          Pattern.class.getCanonicalName(),
+          Preconditions.class.getCanonicalName(),
+          Predicates.class.getCanonicalName(),
+          StandardCharsets.class.getCanonicalName(),
+          Verify.class.getCanonicalName(),
+          "com.fasterxml.jackson.annotation.JsonCreator.Mode",
+          "com.fasterxml.jackson.annotation.JsonFormat.Shape",
+          "com.fasterxml.jackson.annotation.JsonInclude.Include",
+          "com.fasterxml.jackson.annotation.JsonProperty.Access",
           "com.mongodb.client.model.Accumulators",
           "com.mongodb.client.model.Aggregates",
           "com.mongodb.client.model.Filters",
@@ -76,12 +112,6 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
           "com.mongodb.client.model.Projections",
           "com.mongodb.client.model.Sorts",
           "com.mongodb.client.model.Updates",
-          "java.nio.charset.StandardCharsets",
-          "java.util.Collections",
-          "java.util.Comparator",
-          "java.util.Map.Entry",
-          "java.util.regex.Pattern",
-          "java.util.stream.Collectors",
           "org.assertj.core.api.Assertions",
           "org.assertj.core.api.InstanceOfAssertFactories",
           "org.assertj.core.api.SoftAssertions",
@@ -102,95 +132,59 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
           "org.springframework.http.MediaType",
           "org.testng.Assert",
           "reactor.function.TupleUtils",
-          "tech.picnic.errorprone.bugpatterns.util.MoreTypes");
+          "tech.picnic.errorprone.utils.MoreTypes");
 
-  /** Type members that should be statically imported. */
-  @VisibleForTesting
+  /**
+   * Type members that should be statically imported.
+   *
+   * <p>Please note that:
+   *
+   * <ul>
+   *   <li>Types listed by {@link #STATIC_IMPORT_CANDIDATE_TYPES} should be omitted from this
+   *       collection.
+   *   <li>This collection should be mutually exclusive with {@link
+   *       NonStaticImport#NON_STATIC_IMPORT_CANDIDATE_MEMBERS}.
+   *   <li>This collection should not list members contained in {@link
+   *       NonStaticImport#NON_STATIC_IMPORT_CANDIDATE_IDENTIFIERS}.
+   * </ul>
+   */
   static final ImmutableSetMultimap<String, String> STATIC_IMPORT_CANDIDATE_MEMBERS =
       ImmutableSetMultimap.<String, String>builder()
+          .putAll(Comparators.class.getCanonicalName(), "emptiesFirst", "emptiesLast")
+          .put(Function.class.getCanonicalName(), "identity")
+          .put(Functions.class.getCanonicalName(), "identity")
+          .put(ImmutableList.class.getCanonicalName(), "toImmutableList")
           .putAll(
-              "com.google.common.collect.ImmutableListMultimap",
+              ImmutableListMultimap.class.getCanonicalName(),
               "flatteningToImmutableListMultimap",
               "toImmutableListMultimap")
-          .put("com.google.common.collect.ImmutableList", "toImmutableList")
-          .put("com.google.common.collect.ImmutableMap", "toImmutableMap")
-          .put("com.google.common.collect.ImmutableMultiset", "toImmutableMultiset")
-          .put("com.google.common.collect.ImmutableRangeSet", "toImmutableRangeSet")
+          .put(ImmutableMap.class.getCanonicalName(), "toImmutableMap")
+          .put(ImmutableMultiset.class.getCanonicalName(), "toImmutableMultiset")
+          .put(ImmutableRangeSet.class.getCanonicalName(), "toImmutableRangeSet")
+          .put(ImmutableSet.class.getCanonicalName(), "toImmutableSet")
           .putAll(
-              "com.google.common.collect.ImmutableSetMultimap",
+              ImmutableSetMultimap.class.getCanonicalName(),
               "flatteningToImmutableSetMultimap",
               "toImmutableSetMultimap")
-          .put("com.google.common.collect.ImmutableSet", "toImmutableSet")
-          .put("com.google.common.collect.ImmutableSortedMap", "toImmutableSortedMap")
-          .put("com.google.common.collect.ImmutableSortedMultiset", "toImmutableSortedMultiset")
-          .put("com.google.common.collect.ImmutableSortedSet", "toImmutableSortedSet")
-          .put("com.google.common.collect.ImmutableTable", "toImmutableTable")
-          .put("com.google.common.collect.Sets", "toImmutableEnumSet")
-          .put("com.google.common.base.Functions", "identity")
-          .put("java.time.ZoneOffset", "UTC")
-          .put("java.util.function.Function", "identity")
-          .put("java.util.function.Predicate", "not")
-          .put("java.util.UUID", "randomUUID")
-          .put("org.junit.jupiter.params.provider.Arguments", "arguments")
+          .put(ImmutableSortedMap.class.getCanonicalName(), "toImmutableSortedMap")
+          .put(ImmutableSortedMultiset.class.getCanonicalName(), "toImmutableSortedMultiset")
+          .put(ImmutableSortedSet.class.getCanonicalName(), "toImmutableSortedSet")
+          .put(ImmutableTable.class.getCanonicalName(), "toImmutableTable")
           .putAll(
-              "java.util.Objects",
+              Objects.class.getCanonicalName(),
               "checkIndex",
               "checkFromIndexSize",
               "checkFromToIndex",
               "requireNonNull",
               "requireNonNullElse",
               "requireNonNullElseGet")
-          .putAll("com.google.common.collect.Comparators", "emptiesFirst", "emptiesLast")
+          .put(Predicate.class.getCanonicalName(), "not")
+          .put(Sets.class.getCanonicalName(), "toImmutableEnumSet")
+          .put(UUID.class.getCanonicalName(), "randomUUID")
+          .put(ZoneOffset.class.getCanonicalName(), "UTC")
+          .put("org.junit.jupiter.params.provider.Arguments", "arguments")
           .build();
 
-  /**
-   * Type members that should never be statically imported.
-   *
-   * <p>Identifiers listed by {@link #STATIC_IMPORT_EXEMPTED_IDENTIFIERS} should be omitted from
-   * this collection.
-   */
-  // XXX: Perhaps the set of exempted `java.util.Collections` methods is too strict. For now any
-  // method name that could be considered "too vague" or could conceivably mean something else in a
-  // specific context is left out.
-  @VisibleForTesting
-  static final ImmutableSetMultimap<String, String> STATIC_IMPORT_EXEMPTED_MEMBERS =
-      ImmutableSetMultimap.<String, String>builder()
-          .put("com.mongodb.client.model.Filters", "empty")
-          .putAll(
-              "java.util.Collections",
-              "addAll",
-              "copy",
-              "fill",
-              "list",
-              "max",
-              "min",
-              "nCopies",
-              "rotate",
-              "sort",
-              "swap")
-          .putAll("java.util.regex.Pattern", "compile", "matches", "quote")
-          .put("org.springframework.http.MediaType", "ALL")
-          .build();
-
-  /**
-   * Identifiers that should never be statically imported.
-   *
-   * <p>This should be a superset of the identifiers flagged by {@link
-   * com.google.errorprone.bugpatterns.BadImport}.
-   */
-  @VisibleForTesting
-  static final ImmutableSet<String> STATIC_IMPORT_EXEMPTED_IDENTIFIERS =
-      ImmutableSet.of(
-          "builder",
-          "create",
-          "copyOf",
-          "from",
-          "getDefaultInstance",
-          "INSTANCE",
-          "newBuilder",
-          "of",
-          "valueOf");
-
   /** Instantiates a new {@link StaticImport} instance. */
   public StaticImport() {}
 
@@ -228,13 +222,13 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
 
   private static boolean isCandidate(MemberSelectTree tree) {
     String identifier = tree.getIdentifier().toString();
-    if (STATIC_IMPORT_EXEMPTED_IDENTIFIERS.contains(identifier)) {
+    if (NON_STATIC_IMPORT_CANDIDATE_IDENTIFIERS.contains(identifier)) {
       return false;
     }
 
     Type type = ASTHelpers.getType(tree.getExpression());
     return type != null
-        && !STATIC_IMPORT_EXEMPTED_MEMBERS.containsEntry(type.toString(), identifier);
+        && !NON_STATIC_IMPORT_CANDIDATE_MEMBERS.containsEntry(type.toString(), identifier);
   }
 
   private static Optional<String> getCandidateSimpleName(StaticImportInfo importInfo) {

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/StringJoin.java

@@ -4,7 +4,7 @@ import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
 import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
 import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
@@ -23,12 +23,12 @@ import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.tools.javac.code.Type;
-import com.sun.tools.javac.util.Convert;
+import com.sun.tools.javac.util.Constants;
 import java.util.Formattable;
 import java.util.Iterator;
 import java.util.List;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /**
  * A {@link BugChecker} that flags {@link String#format(String, Object...)} invocations which can be
@@ -49,7 +49,7 @@ public final class StringJoin extends BugChecker implements MethodInvocationTree
   private static final long serialVersionUID = 1L;
   private static final Splitter FORMAT_SPECIFIER_SPLITTER = Splitter.on("%s");
   private static final Matcher<ExpressionTree> STRING_FORMAT_INVOCATION =
-      staticMethod().onClass(String.class.getName()).named("format");
+      staticMethod().onClass(String.class.getCanonicalName()).named("format");
   private static final Supplier<Type> CHAR_SEQUENCE_TYPE =
       Suppliers.typeFromClass(CharSequence.class);
   private static final Supplier<Type> FORMATTABLE_TYPE = Suppliers.typeFromClass(Formattable.class);
@@ -150,7 +150,7 @@ public final class StringJoin extends BugChecker implements MethodInvocationTree
     SuggestedFix.Builder fix =
         SuggestedFix.builder()
             .replace(tree.getMethodSelect(), "String.join")
-            .replace(arguments.next(), String.format("\"%s\"", Convert.quote(separator)));
+            .replace(arguments.next(), Constants.format(separator));
 
     while (arguments.hasNext()) {
       ExpressionTree argument = arguments.next();

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

@@ -10,7 +10,7 @@ import static com.google.errorprone.matchers.Matchers.instanceMethod;
 import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
 import static com.google.errorprone.matchers.Matchers.not;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
 
 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -45,11 +45,11 @@ public final class TimeZoneUsage extends BugChecker implements MethodInvocationT
       anyOf(
           allOf(
               instanceMethod()
-                  .onDescendantOf(Clock.class.getName())
+                  .onDescendantOf(Clock.class.getCanonicalName())
                   .namedAnyOf("getZone", "withZone"),
               not(enclosingClass(isSubtypeOf(Clock.class)))),
           staticMethod()
-              .onClass(Clock.class.getName())
+              .onClass(Clock.class.getCanonicalName())
               .namedAnyOf(
                   "system",
                   "systemDefaultZone",
@@ -59,14 +59,17 @@ public final class TimeZoneUsage extends BugChecker implements MethodInvocationT
                   "tickSeconds"),
           staticMethod()
               .onClassAny(
-                  LocalDate.class.getName(),
-                  LocalDateTime.class.getName(),
-                  LocalTime.class.getName(),
-                  OffsetDateTime.class.getName(),
-                  OffsetTime.class.getName(),
-                  ZonedDateTime.class.getName())
+                  LocalDate.class.getCanonicalName(),
+                  LocalDateTime.class.getCanonicalName(),
+                  LocalTime.class.getCanonicalName(),
+                  OffsetDateTime.class.getCanonicalName(),
+                  OffsetTime.class.getCanonicalName(),
+                  ZonedDateTime.class.getCanonicalName())
               .named("now"),
-          staticMethod().onClassAny(Instant.class.getName()).named("now").withNoParameters());
+          staticMethod()
+              .onClassAny(Instant.class.getCanonicalName())
+              .named("now")
+              .withNoParameters());
 
   /** Instantiates a new {@link TimeZoneUsage} instance. */
   public TimeZoneUsage() {}

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

@@ -1,39 +0,0 @@
-package tech.picnic.errorprone.bugpatterns.util;
-
-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.sun.source.tree.AnnotationTree;
-import com.sun.tools.javac.code.Symbol;
-
-/**
- * A collection of general-purpose {@link Matcher}s.
- *
- * <p>These methods are additions to the ones found in {@link Matchers}.
- */
-public final class MoreMatchers {
-  private MoreMatchers() {}
-
-  /**
-   * Returns a {@link Matcher} that determines whether a given {@link AnnotationTree} has a
-   * meta-annotation of the specified type.
-   *
-   * @param <T> The type of tree to match against.
-   * @param annotationType The binary type name of the annotation (e.g.
-   *     "org.jspecify.annotations.Nullable", or "some.package.OuterClassName$InnerClassName")
-   * @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);
-    };
-  }
-
-  // XXX: Consider moving to a `MoreTypePredicates` utility class.
-  private static TypePredicate hasAnnotation(String annotationClassName) {
-    return (type, state) -> ASTHelpers.hasAnnotation(type.tsym, annotationClassName, state);
-  }
-}

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

@@ -3,80 +3,40 @@ package tech.picnic.errorprone.refasterrules;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.google.common.collect.ImmutableBiMap;
-import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableMultiset;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ImmutableSortedMap;
-import com.google.common.collect.ImmutableSortedMultiset;
-import com.google.common.collect.ImmutableSortedSet;
 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.UseImportPolicy;
-import java.util.ArrayList;
 import java.util.Collection;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.LinkedHashMap;
-import java.util.LinkedHashSet;
 import java.util.Map;
 import java.util.Set;
-import java.util.TreeMap;
-import java.util.TreeSet;
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AbstractBooleanAssert;
 import org.assertj.core.api.AbstractCollectionAssert;
 import org.assertj.core.api.AbstractMapAssert;
 import org.assertj.core.api.MapAssert;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.matchers.IsEmpty;
 
 @OnlineDocumentation
 final class AssertJMapRules {
   private AssertJMapRules() {}
 
-  // XXX: Reduce boilerplate using a `Matcher` that identifies "empty" instances.
   static final class AbstractMapAssertIsEmpty<K, V> {
     @BeforeTemplate
-    @SuppressWarnings("unchecked")
-    void before(AbstractMapAssert<?, ?, K, V> mapAssert) {
+    void before(
+        AbstractMapAssert<?, ?, K, V> mapAssert,
+        @Matches(IsEmpty.class) Map<? extends K, ? extends V> wellTypedMap,
+        @Matches(IsEmpty.class) Map<?, ?> arbitrarilyTypedMap,
+        @Matches(IsEmpty.class) Iterable<? extends K> keys) {
       Refaster.anyOf(
-          mapAssert.containsExactlyEntriesOf(
-              Refaster.anyOf(
-                  ImmutableMap.of(),
-                  ImmutableBiMap.of(),
-                  ImmutableSortedMap.of(),
-                  new HashMap<>(),
-                  new LinkedHashMap<>(),
-                  new TreeMap<>())),
-          mapAssert.hasSameSizeAs(
-              Refaster.anyOf(
-                  ImmutableMap.of(),
-                  ImmutableBiMap.of(),
-                  ImmutableSortedMap.of(),
-                  new HashMap<>(),
-                  new LinkedHashMap<>(),
-                  new TreeMap<>())),
-          mapAssert.isEqualTo(
-              Refaster.anyOf(
-                  ImmutableMap.of(),
-                  ImmutableBiMap.of(),
-                  ImmutableSortedMap.of(),
-                  new HashMap<>(),
-                  new LinkedHashMap<>(),
-                  new TreeMap<>())),
-          mapAssert.containsOnlyKeys(
-              Refaster.anyOf(
-                  ImmutableList.of(),
-                  new ArrayList<>(),
-                  ImmutableSet.of(),
-                  new HashSet<>(),
-                  new LinkedHashSet<>(),
-                  ImmutableSortedSet.of(),
-                  new TreeSet<>(),
-                  ImmutableMultiset.of(),
-                  ImmutableSortedMultiset.of())),
+          mapAssert.containsExactlyEntriesOf(wellTypedMap),
+          mapAssert.containsExactlyInAnyOrderEntriesOf(wellTypedMap),
+          mapAssert.hasSameSizeAs(arbitrarilyTypedMap),
+          mapAssert.isEqualTo(arbitrarilyTypedMap),
+          mapAssert.containsOnlyKeys(keys),
           mapAssert.containsExactly(),
           mapAssert.containsOnly(),
           mapAssert.containsOnlyKeys());
@@ -112,15 +72,9 @@ final class AssertJMapRules {
 
   static final class AbstractMapAssertIsNotEmpty<K, V> {
     @BeforeTemplate
-    AbstractMapAssert<?, ?, K, V> before(AbstractMapAssert<?, ?, K, V> mapAssert) {
-      return mapAssert.isNotEqualTo(
-          Refaster.anyOf(
-              ImmutableMap.of(),
-              ImmutableBiMap.of(),
-              ImmutableSortedMap.of(),
-              new HashMap<>(),
-              new LinkedHashMap<>(),
-              new TreeMap<>()));
+    AbstractMapAssert<?, ?, K, V> before(
+        AbstractMapAssert<?, ?, K, V> mapAssert, @Matches(IsEmpty.class) Map<?, ?> map) {
+      return mapAssert.isNotEqualTo(map);
     }
 
     @AfterTemplate
@@ -148,12 +102,14 @@ final class AssertJMapRules {
 
   static final class AbstractMapAssertContainsExactlyInAnyOrderEntriesOf<K, V> {
     @BeforeTemplate
-    AbstractMapAssert<?, ?, K, V> before(AbstractMapAssert<?, ?, K, V> mapAssert, Map<K, V> map) {
+    AbstractMapAssert<?, ?, K, V> before(
+        AbstractMapAssert<?, ?, K, V> mapAssert, Map<? extends K, ? extends V> map) {
       return mapAssert.isEqualTo(map);
     }
 
     @AfterTemplate
-    AbstractMapAssert<?, ?, K, V> after(AbstractMapAssert<?, ?, K, V> mapAssert, Map<K, V> map) {
+    AbstractMapAssert<?, ?, K, V> after(
+        AbstractMapAssert<?, ?, K, V> mapAssert, Map<? extends K, ? extends V> map) {
       return mapAssert.containsExactlyInAnyOrderEntriesOf(map);
     }
   }
@@ -187,12 +143,12 @@ final class AssertJMapRules {
 
   static final class AbstractMapAssertHasSameSizeAs<K, V> {
     @BeforeTemplate
-    AbstractMapAssert<?, ?, K, V> before(AbstractMapAssert<?, ?, K, V> mapAssert, Map<K, V> map) {
+    AbstractMapAssert<?, ?, K, V> before(AbstractMapAssert<?, ?, K, V> mapAssert, Map<?, ?> map) {
       return mapAssert.hasSize(map.size());
     }
 
     @AfterTemplate
-    AbstractMapAssert<?, ?, K, V> after(AbstractMapAssert<?, ?, K, V> mapAssert, Map<K, V> map) {
+    AbstractMapAssert<?, ?, K, V> after(AbstractMapAssert<?, ?, K, V> mapAssert, Map<?, ?> map) {
       return mapAssert.hasSameSizeAs(map);
     }
   }
@@ -225,13 +181,14 @@ final class AssertJMapRules {
 
   static final class AssertThatMapContainsOnlyKeys<K, V> {
     @BeforeTemplate
-    AbstractCollectionAssert<?, Collection<? extends K>, K, ?> before(Map<K, V> map, Set<K> keys) {
+    AbstractCollectionAssert<?, Collection<? extends K>, K, ?> before(
+        Map<K, V> map, Set<? extends K> keys) {
       return assertThat(map.keySet()).hasSameElementsAs(keys);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    MapAssert<K, V> after(Map<K, V> map, Set<K> keys) {
+    MapAssert<K, V> after(Map<K, V> map, Set<? extends K> keys) {
       return assertThat(map).containsOnlyKeys(keys);
     }
   }

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

@@ -6,28 +6,23 @@ import static org.assertj.core.api.Assertions.assertThat;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMultiset;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ImmutableSortedMultiset;
-import com.google.common.collect.ImmutableSortedSet;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Multiset;
 import com.google.errorprone.refaster.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.NotMatches;
 import com.google.errorprone.refaster.annotation.Repeated;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
-import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
-import java.util.HashSet;
-import java.util.LinkedHashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.OptionalDouble;
 import java.util.OptionalInt;
 import java.util.OptionalLong;
 import java.util.Set;
-import java.util.TreeSet;
 import java.util.function.Predicate;
 import java.util.stream.Collector;
 import java.util.stream.Stream;
@@ -47,6 +42,7 @@ import org.assertj.core.api.OptionalIntAssert;
 import org.assertj.core.api.OptionalLongAssert;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 import tech.picnic.errorprone.refaster.matchers.IsArray;
+import tech.picnic.errorprone.refaster.matchers.IsEmpty;
 
 /** Refaster rules related to AssertJ expressions and statements. */
 // XXX: Most `AbstractIntegerAssert` rules can also be applied for other primitive types. Generate
@@ -181,63 +177,16 @@ final class AssertJRules {
   static final class AssertThatObjectEnumerableIsEmpty<E> {
     @BeforeTemplate
     @SuppressWarnings("unchecked")
-    void before(ObjectEnumerableAssert<?, E> enumAssert) {
+    void before(
+        ObjectEnumerableAssert<?, E> enumAssert,
+        @Matches(IsEmpty.class) Iterable<? extends E> wellTypedIterable,
+        @Matches(IsEmpty.class) Iterable<?> arbitrarilyTypedIterable) {
       Refaster.anyOf(
-          enumAssert.containsExactlyElementsOf(
-              Refaster.anyOf(
-                  ImmutableList.of(),
-                  new ArrayList<>(),
-                  ImmutableSet.of(),
-                  new HashSet<>(),
-                  new LinkedHashSet<>(),
-                  ImmutableSortedSet.of(),
-                  new TreeSet<>(),
-                  ImmutableMultiset.of(),
-                  ImmutableSortedMultiset.of())),
-          enumAssert.containsExactlyInAnyOrderElementsOf(
-              Refaster.anyOf(
-                  ImmutableList.of(),
-                  new ArrayList<>(),
-                  ImmutableSet.of(),
-                  new HashSet<>(),
-                  new LinkedHashSet<>(),
-                  ImmutableSortedSet.of(),
-                  new TreeSet<>(),
-                  ImmutableMultiset.of(),
-                  ImmutableSortedMultiset.of())),
-          enumAssert.hasSameElementsAs(
-              Refaster.anyOf(
-                  ImmutableList.of(),
-                  new ArrayList<>(),
-                  ImmutableSet.of(),
-                  new HashSet<>(),
-                  new LinkedHashSet<>(),
-                  ImmutableSortedSet.of(),
-                  new TreeSet<>(),
-                  ImmutableMultiset.of(),
-                  ImmutableSortedMultiset.of())),
-          enumAssert.hasSameSizeAs(
-              Refaster.anyOf(
-                  ImmutableList.of(),
-                  new ArrayList<>(),
-                  ImmutableSet.of(),
-                  new HashSet<>(),
-                  new LinkedHashSet<>(),
-                  ImmutableSortedSet.of(),
-                  new TreeSet<>(),
-                  ImmutableMultiset.of(),
-                  ImmutableSortedMultiset.of())),
-          enumAssert.isSubsetOf(
-              Refaster.anyOf(
-                  ImmutableList.of(),
-                  new ArrayList<>(),
-                  ImmutableSet.of(),
-                  new HashSet<>(),
-                  new LinkedHashSet<>(),
-                  ImmutableSortedSet.of(),
-                  new TreeSet<>(),
-                  ImmutableMultiset.of(),
-                  ImmutableSortedMultiset.of())),
+          enumAssert.containsExactlyElementsOf(wellTypedIterable),
+          enumAssert.containsExactlyInAnyOrderElementsOf(wellTypedIterable),
+          enumAssert.hasSameElementsAs(wellTypedIterable),
+          enumAssert.hasSameSizeAs(arbitrarilyTypedIterable),
+          enumAssert.isSubsetOf(wellTypedIterable),
           enumAssert.containsExactly(),
           enumAssert.containsExactlyInAnyOrder(),
           enumAssert.containsOnly(),
@@ -581,13 +530,13 @@ final class AssertJRules {
   static final class AssertThatStreamContainsAnyElementsOf<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).containsAnyElementsOf(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsAnyElementsOf(iterable);
     }
 
@@ -602,13 +551,13 @@ final class AssertJRules {
   static final class AssertThatStreamContainsAnyOf<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).containsAnyOf(array);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsAnyOf(array);
     }
 
@@ -624,14 +573,14 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsAnyOf" /* Varargs converted to array. */)
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).containsAnyOf(Refaster.asVarargs(elements));
     }
 
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsAnyOf" /* Varargs converted to array. */)
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsAnyOf(Refaster.asVarargs(elements));
     }
 
@@ -647,13 +596,13 @@ final class AssertJRules {
   static final class AssertThatStreamContainsAll<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).containsAll(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsAll(iterable);
     }
 
@@ -668,13 +617,13 @@ final class AssertJRules {
   static final class AssertThatStreamContains<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).contains(array);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).contains(array);
     }
 
@@ -690,14 +639,14 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContains" /* Varargs converted to array. */)
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).contains(Refaster.asVarargs(elements));
     }
 
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContains" /* Varargs converted to array. */)
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).contains(Refaster.asVarargs(elements));
     }
 
@@ -712,7 +661,7 @@ final class AssertJRules {
   static final class AssertThatStreamContainsExactlyElementsOf<S, T extends S, U extends T> {
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsExactlyElementsOf(iterable);
     }
 
@@ -727,7 +676,7 @@ final class AssertJRules {
   static final class AssertThatStreamContainsExactly<S, T extends S, U extends T> {
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsExactly(array);
     }
 
@@ -743,7 +692,7 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsExactly" /* Varargs converted to array. */)
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsExactly(Refaster.asVarargs(elements));
     }
 
@@ -759,13 +708,13 @@ final class AssertJRules {
       S, T extends S, U extends T> {
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsExactlyInAnyOrderElementsOf(iterable);
     }
 
     @BeforeTemplate
     AbstractCollectionAssert<?, ?, T, ?> before2(
-        Stream<S> stream, Collector<S, ?, ? extends Multiset<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends Multiset<T>> collector) {
       return assertThat(stream.collect(collector)).containsExactlyInAnyOrderElementsOf(iterable);
     }
 
@@ -780,13 +729,13 @@ final class AssertJRules {
   static final class AssertThatStreamContainsExactlyInAnyOrder<S, T extends S, U extends T> {
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsExactlyInAnyOrder(array);
     }
 
     @BeforeTemplate
     AbstractCollectionAssert<?, ?, T, ?> before2(
-        Stream<S> stream, Collector<S, ?, ? extends Multiset<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends Multiset<T>> collector) {
       return assertThat(stream.collect(collector)).containsExactlyInAnyOrder(array);
     }
 
@@ -802,7 +751,7 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsExactlyInAnyOrder" /* Varargs converted to array. */)
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector))
           .containsExactlyInAnyOrder(Refaster.asVarargs(elements));
     }
@@ -810,7 +759,7 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsExactlyInAnyOrder" /* Varargs converted to array. */)
     AbstractCollectionAssert<?, ?, T, ?> before2(
-        Stream<S> stream, Collector<S, ?, ? extends Multiset<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends Multiset<T>> collector) {
       return assertThat(stream.collect(collector))
           .containsExactlyInAnyOrder(Refaster.asVarargs(elements));
     }
@@ -827,13 +776,13 @@ final class AssertJRules {
   static final class AssertThatStreamContainsSequence<S, T extends S, U extends T> {
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsSequence(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] iterable) {
+        Stream<S> stream, U[] iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsSequence(iterable);
     }
 
@@ -849,7 +798,7 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsSequence" /* Varargs converted to array. */)
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsSequence(Refaster.asVarargs(elements));
     }
 
@@ -865,13 +814,13 @@ final class AssertJRules {
   static final class AssertThatStreamContainsSubsequence<S, T extends S, U extends T> {
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsSubsequence(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] iterable) {
+        Stream<S> stream, U[] iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsSubsequence(iterable);
     }
 
@@ -887,7 +836,7 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsSubsequence" /* Varargs converted to array. */)
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector))
           .containsSubsequence(Refaster.asVarargs(elements));
     }
@@ -904,13 +853,13 @@ final class AssertJRules {
   static final class AssertThatStreamDoesNotContainAnyElementsOf<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContainAnyElementsOf(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContainAnyElementsOf(iterable);
     }
 
@@ -925,13 +874,13 @@ final class AssertJRules {
   static final class AssertThatStreamDoesNotContain<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContain(array);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContain(array);
     }
 
@@ -947,14 +896,14 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamDoesNotContain" /* Varargs converted to array. */)
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContain(Refaster.asVarargs(elements));
     }
 
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamDoesNotContain" /* Varargs converted to array. */)
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContain(Refaster.asVarargs(elements));
     }
 
@@ -969,13 +918,13 @@ final class AssertJRules {
   static final class AssertThatStreamDoesNotContainSequence<S, T extends S, U extends T> {
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContainSequence(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] iterable) {
+        Stream<S> stream, U[] iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).doesNotContainSequence(iterable);
     }
 
@@ -991,7 +940,7 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamDoesNotContainSequence" /* Varargs converted to array. */)
     ListAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector))
           .doesNotContainSequence(Refaster.asVarargs(elements));
     }
@@ -1008,13 +957,13 @@ final class AssertJRules {
   static final class AssertThatStreamHasSameElementsAs<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).hasSameElementsAs(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).hasSameElementsAs(iterable);
     }
 
@@ -1029,13 +978,13 @@ final class AssertJRules {
   static final class AssertThatStreamContainsOnly<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).containsOnly(array);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] array) {
+        Stream<S> stream, U[] array, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsOnly(array);
     }
 
@@ -1051,14 +1000,14 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsOnly" /* Varargs converted to array. */)
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).containsOnly(Refaster.asVarargs(elements));
     }
 
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamContainsOnly" /* Varargs converted to array. */)
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).containsOnly(Refaster.asVarargs(elements));
     }
 
@@ -1073,25 +1022,25 @@ final class AssertJRules {
   static final class AssertThatStreamIsSubsetOf<S, T extends S, U extends T> {
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).isSubsetOf(iterable);
     }
 
     @BeforeTemplate
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, U[] iterable) {
+        Stream<S> stream, U[] iterable, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).isSubsetOf(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, Iterable<U> iterable) {
+        Stream<S> stream, Iterable<U> iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).isSubsetOf(iterable);
     }
 
     @BeforeTemplate
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, U[] iterable) {
+        Stream<S> stream, U[] iterable, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).isSubsetOf(iterable);
     }
 
@@ -1107,14 +1056,14 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamIsSubsetOf" /* Varargs converted to array. */)
     IterableAssert<T> before(
-        Stream<S> stream, Collector<S, ?, ? extends Iterable<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends Iterable<T>> collector) {
       return assertThat(stream.collect(collector)).isSubsetOf(Refaster.asVarargs(elements));
     }
 
     @BeforeTemplate
     @SuppressWarnings("AssertThatStreamIsSubsetOf" /* Varargs converted to array. */)
     ListAssert<T> before2(
-        Stream<S> stream, Collector<S, ?, ? extends List<T>> collector, @Repeated U elements) {
+        Stream<S> stream, @Repeated U elements, Collector<S, ?, ? extends List<T>> collector) {
       return assertThat(stream.collect(collector)).isSubsetOf(Refaster.asVarargs(elements));
     }
 

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

@@ -455,14 +455,14 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownBy {
     @BeforeTemplate
     AbstractObjectAssert<?, ?> before(
-        Class<? extends Throwable> exceptionType, ThrowingCallable throwingCallable) {
+        ThrowingCallable throwingCallable, Class<? extends Throwable> exceptionType) {
       return assertThatExceptionOfType(exceptionType).isThrownBy(throwingCallable);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, ?> after(
-        Class<? extends Throwable> exceptionType, ThrowingCallable throwingCallable) {
+        ThrowingCallable throwingCallable, Class<? extends Throwable> exceptionType) {
       return assertThatThrownBy(throwingCallable).isInstanceOf(exceptionType);
     }
   }
@@ -471,8 +471,8 @@ final class AssertJThrowingCallableRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatExceptionOfType(exceptionType)
           .isThrownBy(throwingCallable)
@@ -482,8 +482,8 @@ final class AssertJThrowingCallableRules {
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, ?> after(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatThrownBy(throwingCallable).isInstanceOf(exceptionType).hasMessage(message);
     }
@@ -493,8 +493,8 @@ final class AssertJThrowingCallableRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message,
         @Repeated Object parameters) {
       return assertThatExceptionOfType(exceptionType)
@@ -505,8 +505,8 @@ final class AssertJThrowingCallableRules {
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, ?> after(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message,
         @Repeated Object parameters) {
       return assertThatThrownBy(throwingCallable)
@@ -519,8 +519,8 @@ final class AssertJThrowingCallableRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatExceptionOfType(exceptionType)
           .isThrownBy(throwingCallable)
@@ -530,8 +530,8 @@ final class AssertJThrowingCallableRules {
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, ?> after(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatThrownBy(throwingCallable)
           .isInstanceOf(exceptionType)
@@ -543,8 +543,8 @@ final class AssertJThrowingCallableRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatExceptionOfType(exceptionType)
           .isThrownBy(throwingCallable)
@@ -554,8 +554,8 @@ final class AssertJThrowingCallableRules {
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, ?> after(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatThrownBy(throwingCallable)
           .isInstanceOf(exceptionType)
@@ -567,8 +567,8 @@ final class AssertJThrowingCallableRules {
     @BeforeTemplate
     @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatExceptionOfType(exceptionType)
           .isThrownBy(throwingCallable)
@@ -578,8 +578,8 @@ final class AssertJThrowingCallableRules {
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     AbstractObjectAssert<?, ?> after(
-        Class<? extends Throwable> exceptionType,
         ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
         String message) {
       return assertThatThrownBy(throwingCallable)
           .isInstanceOf(exceptionType)

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/BigDecimalRules.java

@@ -2,6 +2,7 @@ package tech.picnic.errorprone.refasterrules;
 
 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 java.math.BigDecimal;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
@@ -66,4 +67,61 @@ final class BigDecimalRules {
       return BigDecimal.valueOf(value);
     }
   }
+
+  /** Prefer using {@link BigDecimal#signum()} over more contrived alternatives. */
+  static final class BigDecimalSignumIsZero {
+    @BeforeTemplate
+    boolean before(BigDecimal value) {
+      return Refaster.anyOf(
+          value.compareTo(BigDecimal.ZERO) == 0, BigDecimal.ZERO.compareTo(value) == 0);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(BigDecimal value) {
+      return value.signum() == 0;
+    }
+  }
+
+  /**
+   * Prefer a {@link BigDecimal#signum()} comparison to 1 over more contrived or less clear
+   * alternatives.
+   */
+  static final class BigDecimalSignumIsPositive {
+    @BeforeTemplate
+    boolean before(BigDecimal value) {
+      return Refaster.anyOf(
+          value.compareTo(BigDecimal.ZERO) > 0,
+          BigDecimal.ZERO.compareTo(value) < 0,
+          value.signum() > 0,
+          value.signum() >= 1);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(BigDecimal value) {
+      return value.signum() == 1;
+    }
+  }
+
+  /**
+   * Prefer a {@link BigDecimal#signum()} comparison to -1 over more contrived or less clear
+   * alternatives.
+   */
+  static final class BigDecimalSignumIsNegative {
+    @BeforeTemplate
+    boolean before(BigDecimal value) {
+      return Refaster.anyOf(
+          value.compareTo(BigDecimal.ZERO) < 0,
+          BigDecimal.ZERO.compareTo(value) > 0,
+          value.signum() < 0,
+          value.signum() <= -1);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(BigDecimal value) {
+      return value.signum() == -1;
+    }
+  }
 }

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

@@ -3,9 +3,12 @@ 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;
+import com.sun.tools.javac.util.Constants;
+import com.sun.tools.javac.util.Convert;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
 /** Refaster rules related to {@link com.google.errorprone.bugpatterns.BugChecker} classes. */
@@ -25,6 +28,7 @@ final class BugCheckerRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     BugCheckerRefactoringTestHelper after(BugCheckerRefactoringTestHelper helper) {
       return helper;
     }
@@ -50,4 +54,17 @@ final class BugCheckerRules {
       return helper.addInputLines(path, source).expectUnchanged();
     }
   }
+
+  /** Prefer using the {@link Constants} API over more verbose alternatives. */
+  static final class ConstantsFormat {
+    @BeforeTemplate
+    String before(String value) {
+      return String.format("\"%s\"", Convert.quote(value));
+    }
+
+    @AfterTemplate
+    String after(String value) {
+      return Constants.format(value);
+    }
+  }
 }

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

@@ -7,26 +7,32 @@ import static java.util.Comparator.comparingInt;
 import static java.util.Comparator.comparingLong;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Comparator.reverseOrder;
-import static java.util.function.Function.identity;
+import static java.util.stream.Collectors.maxBy;
+import static java.util.stream.Collectors.minBy;
 
 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;
+import com.google.errorprone.refaster.annotation.Matches;
 import com.google.errorprone.refaster.annotation.Repeated;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.Optional;
 import java.util.function.BinaryOperator;
 import java.util.function.Function;
 import java.util.function.ToDoubleFunction;
 import java.util.function.ToIntFunction;
 import java.util.function.ToLongFunction;
+import java.util.stream.Collector;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.matchers.IsIdentityOperation;
 
 /** Refaster rules related to expressions dealing with {@link Comparator}s. */
 @OnlineDocumentation
@@ -35,12 +41,12 @@ final class ComparatorRules {
 
   /** Prefer {@link Comparator#naturalOrder()} over more complicated constructs. */
   static final class NaturalOrder<T extends Comparable<? super T>> {
-    // XXX: Drop the `Refaster.anyOf` if/when we decide to rewrite one to the other.
     @BeforeTemplate
-    Comparator<T> before() {
+    Comparator<T> before(
+        @Matches(IsIdentityOperation.class) Function<? super T, ? extends T> keyExtractor) {
       return Refaster.anyOf(
           T::compareTo,
-          comparing(Refaster.anyOf(identity(), v -> v)),
+          comparing(keyExtractor),
           Collections.<T>reverseOrder(reverseOrder()),
           Comparator.<T>reverseOrder().reversed());
     }
@@ -71,13 +77,15 @@ final class ComparatorRules {
   }
 
   static final class CustomComparator<T> {
-    // XXX: Drop the `Refaster.anyOf` if/when we decide to rewrite one to the other.
     @BeforeTemplate
-    Comparator<T> before(Comparator<T> cmp) {
-      return comparing(Refaster.anyOf(identity(), v -> v), cmp);
+    Comparator<T> before(
+        Comparator<T> cmp,
+        @Matches(IsIdentityOperation.class) Function<? super T, ? extends T> keyExtractor) {
+      return comparing(keyExtractor, cmp);
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<T> after(Comparator<T> cmp) {
       return cmp;
@@ -181,14 +189,15 @@ final class ComparatorRules {
   }
 
   /**
-   * Where applicable, prefer {@link Comparator#naturalOrder()} over {@link Function#identity()}, as
-   * it more clearly states intent.
+   * Where applicable, prefer {@link Comparator#naturalOrder()} over identity function-based
+   * comparisons, as the former more clearly states intent.
    */
   static final class ThenComparingNaturalOrder<T extends Comparable<? super T>> {
-    // XXX: Drop the `Refaster.anyOf` if/when we decide to rewrite one to the other.
     @BeforeTemplate
-    Comparator<T> before(Comparator<T> cmp) {
-      return cmp.thenComparing(Refaster.anyOf(identity(), v -> v));
+    Comparator<T> before(
+        Comparator<T> cmp,
+        @Matches(IsIdentityOperation.class) Function<? super T, ? extends T> keyExtractor) {
+      return cmp.thenComparing(keyExtractor);
     }
 
     @AfterTemplate
@@ -219,7 +228,6 @@ 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 +295,6 @@ 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();
     }
@@ -380,4 +387,36 @@ final class ComparatorRules {
       return Comparators::max;
     }
   }
+
+  /**
+   * Prefer {@link Comparator#naturalOrder()} over {@link Comparator#reverseOrder()} where possible.
+   */
+  static final class MinByNaturalOrder<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Collector<T, ?, Optional<T>> before() {
+      return maxBy(reverseOrder());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    Collector<T, ?, Optional<T>> after() {
+      return minBy(naturalOrder());
+    }
+  }
+
+  /**
+   * Prefer {@link Comparator#naturalOrder()} over {@link Comparator#reverseOrder()} where possible.
+   */
+  static final class MaxByNaturalOrder<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Collector<T, ?, Optional<T>> before() {
+      return minBy(reverseOrder());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    Collector<T, ?, Optional<T>> after() {
+      return maxBy(naturalOrder());
+    }
+  }
 }

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 +136,52 @@ 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 Equals<T, S> {
+    @BeforeTemplate
+    boolean before(T value1, S value2) {
+      return Refaster.anyOf(
+          Optional.of(value1).equals(Optional.of(value2)),
+          Optional.of(value1).equals(Optional.ofNullable(value2)),
+          Optional.ofNullable(value2).equals(Optional.of(value1)));
+    }
+
+    @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 ObjectsEquals<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/ImmutableListMultimapRules.java

@@ -3,7 +3,6 @@ package tech.picnic.errorprone.refasterrules;
 import static com.google.common.collect.ImmutableListMultimap.flatteningToImmutableListMultimap;
 import static com.google.common.collect.ImmutableListMultimap.toImmutableListMultimap;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
-import static java.util.function.Function.identity;
 
 import com.google.common.collect.ImmutableListMultimap;
 import com.google.common.collect.ImmutableMultimap;
@@ -16,6 +15,7 @@ import com.google.common.collect.Streams;
 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.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
@@ -25,6 +25,7 @@ import java.util.Map;
 import java.util.function.Function;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.matchers.IsIdentityOperation;
 
 /** Refaster rules related to expressions dealing with {@link ImmutableListMultimap}s. */
 @OnlineDocumentation
@@ -173,27 +174,29 @@ final class ImmutableListMultimapRules {
    * Prefer {@link Multimaps#index(Iterable, com.google.common.base.Function)} over the stream-based
    * alternative.
    */
-  // XXX: Drop the `Refaster.anyOf` if/when we decide to rewrite one to the other.
   static final class IndexIterableToImmutableListMultimap<K, V> {
     @BeforeTemplate
     ImmutableListMultimap<K, V> before(
-        Iterator<V> iterable, Function<? super V, ? extends K> keyFunction) {
-      return Streams.stream(iterable)
-          .collect(toImmutableListMultimap(keyFunction, Refaster.anyOf(identity(), v -> v)));
+        Iterator<V> iterable,
+        Function<? super V, ? extends K> keyFunction,
+        @Matches(IsIdentityOperation.class) Function<? super V, ? extends V> valueFunction) {
+      return Streams.stream(iterable).collect(toImmutableListMultimap(keyFunction, valueFunction));
     }
 
     @BeforeTemplate
     ImmutableListMultimap<K, V> before(
-        Iterable<V> iterable, Function<? super V, ? extends K> keyFunction) {
-      return Streams.stream(iterable)
-          .collect(toImmutableListMultimap(keyFunction, Refaster.anyOf(identity(), v -> v)));
+        Iterable<V> iterable,
+        Function<? super V, ? extends K> keyFunction,
+        @Matches(IsIdentityOperation.class) Function<? super V, ? extends V> valueFunction) {
+      return Streams.stream(iterable).collect(toImmutableListMultimap(keyFunction, valueFunction));
     }
 
     @BeforeTemplate
     ImmutableListMultimap<K, V> before(
-        Collection<V> iterable, Function<? super V, ? extends K> keyFunction) {
-      return iterable.stream()
-          .collect(toImmutableListMultimap(keyFunction, Refaster.anyOf(identity(), v -> v)));
+        Collection<V> iterable,
+        Function<? super V, ? extends K> keyFunction,
+        @Matches(IsIdentityOperation.class) Function<? super V, ? extends V> valueFunction) {
+      return iterable.stream().collect(toImmutableListMultimap(keyFunction, valueFunction));
     }
 
     @AfterTemplate

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

@@ -118,17 +118,17 @@ final class ImmutableListRules {
    */
   static final class ImmutableListSortedCopyOfWithCustomComparator<T> {
     @BeforeTemplate
-    ImmutableList<T> before(Iterable<T> iterable, Comparator<T> cmp) {
+    ImmutableList<T> before(Comparator<T> cmp, Iterable<T> iterable) {
       return Streams.stream(iterable).sorted(cmp).collect(toImmutableList());
     }
 
     @BeforeTemplate
-    ImmutableList<T> before(Collection<T> iterable, Comparator<T> cmp) {
+    ImmutableList<T> before(Comparator<T> cmp, Collection<T> iterable) {
       return iterable.stream().sorted(cmp).collect(toImmutableList());
     }
 
     @AfterTemplate
-    ImmutableList<T> after(Collection<T> iterable, Comparator<? super T> cmp) {
+    ImmutableList<T> after(Comparator<? super T> cmp, Collection<T> iterable) {
       return ImmutableList.sortedCopyOf(cmp, iterable);
     }
   }

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

@@ -4,7 +4,6 @@ import static com.google.common.collect.ImmutableMap.toImmutableMap;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Collections.emptyMap;
 import static java.util.Collections.singletonMap;
-import static java.util.function.Function.identity;
 
 import com.google.common.base.Predicate;
 import com.google.common.collect.ImmutableMap;
@@ -13,6 +12,7 @@ import com.google.common.collect.Streams;
 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.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
@@ -23,6 +23,7 @@ import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.matchers.IsIdentityOperation;
 
 /** Refaster rules related to expressions dealing with {@link ImmutableMap}s. */
 @OnlineDocumentation
@@ -63,27 +64,29 @@ final class ImmutableMapRules {
    * Prefer {@link Maps#toMap(Iterable, com.google.common.base.Function)} over more contrived
    * alternatives.
    */
-  // XXX: Drop the `Refaster.anyOf` if/when we decide to rewrite one to the other.
   static final class IterableToImmutableMap<K, V> {
     @BeforeTemplate
     ImmutableMap<K, V> before(
-        Iterator<K> iterable, Function<? super K, ? extends V> valueFunction) {
-      return Streams.stream(iterable)
-          .collect(toImmutableMap(Refaster.anyOf(identity(), k -> k), valueFunction));
+        Iterator<K> iterable,
+        Function<? super K, ? extends V> valueFunction,
+        @Matches(IsIdentityOperation.class) Function<? super K, ? extends K> keyFunction) {
+      return Streams.stream(iterable).collect(toImmutableMap(keyFunction, valueFunction));
     }
 
     @BeforeTemplate
     ImmutableMap<K, V> before(
-        Iterable<K> iterable, Function<? super K, ? extends V> valueFunction) {
-      return Streams.stream(iterable)
-          .collect(toImmutableMap(Refaster.anyOf(identity(), k -> k), valueFunction));
+        Iterable<K> iterable,
+        Function<? super K, ? extends V> valueFunction,
+        @Matches(IsIdentityOperation.class) Function<? super K, ? extends K> keyFunction) {
+      return Streams.stream(iterable).collect(toImmutableMap(keyFunction, valueFunction));
     }
 
     @BeforeTemplate
     ImmutableMap<K, V> before(
-        Collection<K> iterable, Function<? super K, ? extends V> valueFunction) {
-      return iterable.stream()
-          .collect(toImmutableMap(Refaster.anyOf(identity(), k -> k), valueFunction));
+        Collection<K> iterable,
+        Function<? super K, ? extends V> valueFunction,
+        @Matches(IsIdentityOperation.class) Function<? super K, ? extends K> keyFunction) {
+      return iterable.stream().collect(toImmutableMap(keyFunction, valueFunction));
     }
 
     @BeforeTemplate
@@ -157,25 +160,29 @@ final class ImmutableMapRules {
    * Prefer {@link Maps#uniqueIndex(Iterable, com.google.common.base.Function)} over the
    * stream-based alternative.
    */
-  // XXX: Drop the `Refaster.anyOf` if/when we decide to rewrite one to the other.
   static final class IndexIterableToImmutableMap<K, V> {
     @BeforeTemplate
-    ImmutableMap<K, V> before(Iterator<V> iterable, Function<? super V, ? extends K> keyFunction) {
-      return Streams.stream(iterable)
-          .collect(toImmutableMap(keyFunction, Refaster.anyOf(identity(), v -> v)));
-    }
-
-    @BeforeTemplate
-    ImmutableMap<K, V> before(Iterable<V> iterable, Function<? super V, ? extends K> keyFunction) {
-      return Streams.stream(iterable)
-          .collect(toImmutableMap(keyFunction, Refaster.anyOf(identity(), v -> v)));
+    ImmutableMap<K, V> before(
+        Iterator<V> iterable,
+        Function<? super V, ? extends K> keyFunction,
+        @Matches(IsIdentityOperation.class) Function<? super V, ? extends V> valueFunction) {
+      return Streams.stream(iterable).collect(toImmutableMap(keyFunction, valueFunction));
     }
 
     @BeforeTemplate
     ImmutableMap<K, V> before(
-        Collection<V> iterable, Function<? super V, ? extends K> keyFunction) {
-      return iterable.stream()
-          .collect(toImmutableMap(keyFunction, Refaster.anyOf(identity(), v -> v)));
+        Iterable<V> iterable,
+        Function<? super V, ? extends K> keyFunction,
+        @Matches(IsIdentityOperation.class) Function<? super V, ? extends V> valueFunction) {
+      return Streams.stream(iterable).collect(toImmutableMap(keyFunction, valueFunction));
+    }
+
+    @BeforeTemplate
+    ImmutableMap<K, V> before(
+        Collection<V> iterable,
+        Function<? super V, ? extends K> keyFunction,
+        @Matches(IsIdentityOperation.class) Function<? super V, ? extends V> valueFunction) {
+      return iterable.stream().collect(toImmutableMap(keyFunction, valueFunction));
     }
 
     @AfterTemplate

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

@@ -0,0 +1,41 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.io.ByteStreams;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to expressions dealing with {@link InputStream}s. */
+// XXX: Add a rule for `ByteStreams.skipFully(in, n)` -> `in.skipNBytes(n)` once we have a way to
+// target JDK 12+ APIs.
+@OnlineDocumentation
+final class InputStreamRules {
+  private InputStreamRules() {}
+
+  static final class InputStreamTransferTo {
+    @BeforeTemplate
+    long before(InputStream in, OutputStream out) throws IOException {
+      return ByteStreams.copy(in, out);
+    }
+
+    @AfterTemplate
+    long after(InputStream in, OutputStream out) throws IOException {
+      return in.transferTo(out);
+    }
+  }
+
+  static final class InputStreamReadAllBytes {
+    @BeforeTemplate
+    byte[] before(InputStream in) throws IOException {
+      return ByteStreams.toByteArray(in);
+    }
+
+    @AfterTemplate
+    byte[] after(InputStream in) throws IOException {
+      return in.readAllBytes();
+    }
+  }
+}

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/JUnitToAssertJRules.java

@@ -16,7 +16,6 @@ import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.junit.jupiter.api.Assertions.assertThrowsExactly;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
-import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.annotations.DoNotCall;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -44,21 +43,6 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 final class JUnitToAssertJRules {
   private JUnitToAssertJRules() {}
 
-  public ImmutableSet<Object> elidedTypesAndStaticImports() {
-    return ImmutableSet.of(
-        Assertions.class,
-        assertDoesNotThrow(() -> null),
-        assertInstanceOf(null, null),
-        assertThrows(null, null),
-        assertThrowsExactly(null, null),
-        (Runnable) () -> assertFalse(true),
-        (Runnable) () -> assertNotNull(null),
-        (Runnable) () -> assertNotSame(null, null),
-        (Runnable) () -> assertNull(null),
-        (Runnable) () -> assertSame(null, null),
-        (Runnable) () -> assertTrue(true));
-  }
-
   static final class ThrowNewAssertionError {
     @BeforeTemplate
     void before() {
@@ -78,8 +62,13 @@ final class JUnitToAssertJRules {
       return Assertions.fail(message);
     }
 
+    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)` once
+    // https://github.com/google/error-prone/pull/3584 is resolved. Until that time, statically
+    // importing AssertJ's `fail` is likely to clash with an existing static import of JUnit's
+    // `fail`. Note that combining Error Prone's `RemoveUnusedImports` and
+    // `UnnecessarilyFullyQualified` checks and our `StaticImport` check will anyway cause the
+    // method to be imported statically if possible; just in a less efficient manner.
     @AfterTemplate
-    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     T after(String message) {
       return fail(message);
     }
@@ -91,8 +80,13 @@ final class JUnitToAssertJRules {
       return Assertions.fail(message, throwable);
     }
 
+    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)` once
+    // https://github.com/google/error-prone/pull/3584 is resolved. Until that time, statically
+    // importing AssertJ's `fail` is likely to clash with an existing static import of JUnit's
+    // `fail`. Note that combining Error Prone's `RemoveUnusedImports` and
+    // `UnnecessarilyFullyQualified` checks and our `StaticImport` check will anyway cause the
+    // method to be imported statically if possible; just in a less efficient manner.
     @AfterTemplate
-    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     T after(String message, Throwable throwable) {
       return fail(message, throwable);
     }
@@ -282,26 +276,26 @@ final class JUnitToAssertJRules {
 
   static final class AssertThatWithFailMessageStringIsSameAs {
     @BeforeTemplate
-    void before(Object actual, Object expected, String message) {
+    void before(Object actual, String message, Object expected) {
       assertSame(expected, actual, message);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(Object actual, Object expected, String message) {
+    void after(Object actual, String message, Object expected) {
       assertThat(actual).withFailMessage(message).isSameAs(expected);
     }
   }
 
   static final class AssertThatWithFailMessageSupplierIsSameAs {
     @BeforeTemplate
-    void before(Object actual, Object expected, Supplier<String> supplier) {
+    void before(Object actual, Supplier<String> supplier, Object expected) {
       assertSame(expected, actual, supplier);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(Object actual, Object expected, Supplier<String> supplier) {
+    void after(Object actual, Supplier<String> supplier, Object expected) {
       assertThat(actual).withFailMessage(supplier).isSameAs(expected);
     }
   }
@@ -321,26 +315,26 @@ final class JUnitToAssertJRules {
 
   static final class AssertThatWithFailMessageStringIsNotSameAs {
     @BeforeTemplate
-    void before(Object actual, Object expected, String message) {
+    void before(Object actual, String message, Object expected) {
       assertNotSame(expected, actual, message);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(Object actual, Object expected, String message) {
+    void after(Object actual, String message, Object expected) {
       assertThat(actual).withFailMessage(message).isNotSameAs(expected);
     }
   }
 
   static final class AssertThatWithFailMessageSupplierIsNotSameAs {
     @BeforeTemplate
-    void before(Object actual, Object expected, Supplier<String> supplier) {
+    void before(Object actual, Supplier<String> supplier, Object expected) {
       assertNotSame(expected, actual, supplier);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(Object actual, Object expected, Supplier<String> supplier) {
+    void after(Object actual, Supplier<String> supplier, Object expected) {
       assertThat(actual).withFailMessage(supplier).isNotSameAs(expected);
     }
   }
@@ -361,13 +355,13 @@ final class JUnitToAssertJRules {
   static final class AssertThatThrownByWithFailMessageStringIsExactlyInstanceOf<
       T extends Throwable> {
     @BeforeTemplate
-    void before(Executable throwingCallable, Class<T> clazz, String message) {
+    void before(Executable throwingCallable, String message, Class<T> clazz) {
       assertThrowsExactly(clazz, throwingCallable, message);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(ThrowingCallable throwingCallable, Class<T> clazz, String message) {
+    void after(ThrowingCallable throwingCallable, String message, Class<T> clazz) {
       assertThatThrownBy(throwingCallable).withFailMessage(message).isExactlyInstanceOf(clazz);
     }
   }
@@ -375,13 +369,13 @@ final class JUnitToAssertJRules {
   static final class AssertThatThrownByWithFailMessageSupplierIsExactlyInstanceOf<
       T extends Throwable> {
     @BeforeTemplate
-    void before(Executable throwingCallable, Class<T> clazz, Supplier<String> supplier) {
+    void before(Executable throwingCallable, Supplier<String> supplier, Class<T> clazz) {
       assertThrowsExactly(clazz, throwingCallable, supplier);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(ThrowingCallable throwingCallable, Class<T> clazz, Supplier<String> supplier) {
+    void after(ThrowingCallable throwingCallable, Supplier<String> supplier, Class<T> clazz) {
       assertThatThrownBy(throwingCallable).withFailMessage(supplier).isExactlyInstanceOf(clazz);
     }
   }
@@ -401,26 +395,26 @@ final class JUnitToAssertJRules {
 
   static final class AssertThatThrownByWithFailMessageStringIsInstanceOf<T extends Throwable> {
     @BeforeTemplate
-    void before(Executable throwingCallable, Class<T> clazz, String message) {
+    void before(Executable throwingCallable, String message, Class<T> clazz) {
       assertThrows(clazz, throwingCallable, message);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(ThrowingCallable throwingCallable, Class<T> clazz, String message) {
+    void after(ThrowingCallable throwingCallable, String message, Class<T> clazz) {
       assertThatThrownBy(throwingCallable).withFailMessage(message).isInstanceOf(clazz);
     }
   }
 
   static final class AssertThatThrownByWithFailMessageSupplierIsInstanceOf<T extends Throwable> {
     @BeforeTemplate
-    void before(Executable throwingCallable, Class<T> clazz, Supplier<String> supplier) {
+    void before(Executable throwingCallable, Supplier<String> supplier, Class<T> clazz) {
       assertThrows(clazz, throwingCallable, supplier);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(ThrowingCallable throwingCallable, Class<T> clazz, Supplier<String> supplier) {
+    void after(ThrowingCallable throwingCallable, Supplier<String> supplier, Class<T> clazz) {
       assertThatThrownBy(throwingCallable).withFailMessage(supplier).isInstanceOf(clazz);
     }
   }
@@ -494,26 +488,26 @@ final class JUnitToAssertJRules {
 
   static final class AssertThatWithFailMessageStringIsInstanceOf<T> {
     @BeforeTemplate
-    void before(Object actual, Class<T> clazz, String message) {
+    void before(Object actual, String message, Class<T> clazz) {
       assertInstanceOf(clazz, actual, message);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(Object actual, Class<T> clazz, String message) {
+    void after(Object actual, String message, Class<T> clazz) {
       assertThat(actual).withFailMessage(message).isInstanceOf(clazz);
     }
   }
 
   static final class AssertThatWithFailMessageSupplierIsInstanceOf<T> {
     @BeforeTemplate
-    void before(Object actual, Class<T> clazz, Supplier<String> supplier) {
+    void before(Object actual, Supplier<String> supplier, Class<T> clazz) {
       assertInstanceOf(clazz, actual, supplier);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    void after(Object actual, Class<T> clazz, Supplier<String> supplier) {
+    void after(Object actual, Supplier<String> supplier, Class<T> clazz) {
       assertThat(actual).withFailMessage(supplier).isInstanceOf(clazz);
     }
   }

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

@@ -6,7 +6,9 @@ import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import java.util.Collection;
+import java.util.Map;
 import java.util.Set;
+import java.util.stream.Stream;
 import org.jspecify.annotations.Nullable;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
@@ -28,6 +30,21 @@ final class MultimapRules {
     }
   }
 
+  /** Prefer {@link Multimap#isEmpty()} over more contrived alternatives. */
+  static final class MultimapIsEmpty<K, V> {
+    @BeforeTemplate
+    boolean before(Multimap<K, V> multimap) {
+      return Refaster.anyOf(
+              multimap.keySet(), multimap.keys(), multimap.values(), multimap.entries())
+          .isEmpty();
+    }
+
+    @AfterTemplate
+    boolean after(Multimap<K, V> multimap) {
+      return multimap.isEmpty();
+    }
+  }
+
   /** Prefer {@link Multimap#size()} over more contrived alternatives. */
   static final class MultimapSize<K, V> {
     @BeforeTemplate
@@ -41,6 +58,32 @@ final class MultimapRules {
     }
   }
 
+  /** Prefer {@link Multimap#containsKey(Object)} over more contrived alternatives. */
+  static final class MultimapContainsKey<K, V, T> {
+    @BeforeTemplate
+    boolean before(Multimap<K, V> multimap, T key) {
+      return Refaster.anyOf(multimap.keySet(), multimap.keys()).contains(key);
+    }
+
+    @AfterTemplate
+    boolean after(Multimap<K, V> multimap, T key) {
+      return multimap.containsKey(key);
+    }
+  }
+
+  /** Prefer {@link Multimap#containsValue(Object)} over more contrived alternatives. */
+  static final class MultimapContainsValue<K, V, T> {
+    @BeforeTemplate
+    boolean before(Multimap<K, V> multimap, T value) {
+      return multimap.values().contains(value);
+    }
+
+    @AfterTemplate
+    boolean after(Multimap<K, V> multimap, T value) {
+      return multimap.containsValue(value);
+    }
+  }
+
   /**
    * Prefer {@link Multimap#get(Object)} over more contrived alternatives.
    *
@@ -50,8 +93,7 @@ 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);
     }
 
@@ -60,4 +102,30 @@ final class MultimapRules {
       return multimap.get(key);
     }
   }
+
+  /** Don't unnecessarily use {@link Multimap#entries()}. */
+  static final class MultimapKeysStream<K, V> {
+    @BeforeTemplate
+    Stream<K> before(Multimap<K, V> multimap) {
+      return multimap.entries().stream().map(Map.Entry::getKey);
+    }
+
+    @AfterTemplate
+    Stream<K> after(Multimap<K, V> multimap) {
+      return multimap.keys().stream();
+    }
+  }
+
+  /** Don't unnecessarily use {@link Multimap#entries()}. */
+  static final class MultimapValuesStream<K, V> {
+    @BeforeTemplate
+    Stream<V> before(Multimap<K, V> multimap) {
+      return multimap.entries().stream().map(Map.Entry::getValue);
+    }
+
+    @AfterTemplate
+    Stream<V> after(Multimap<K, V> multimap) {
+      return multimap.values().stream();
+    }
+  }
 }

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
@@ -344,6 +388,7 @@ final class OptionalRules {
     @BeforeTemplate
     Optional<T> before(Optional<T> optional, Comparator<? super T> comparator) {
       return Refaster.anyOf(
+          optional.or(Refaster.anyOf(() -> Optional.empty(), Optional::empty)),
           optional.stream().findFirst(),
           optional.stream().findAny(),
           optional.stream().min(comparator),
@@ -351,6 +396,7 @@ final class OptionalRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Optional<T> after(Optional<T> optional) {
       return optional;
     }
@@ -392,12 +438,22 @@ 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/PrimitiveRules.java

@@ -8,7 +8,9 @@ import com.google.common.primitives.Floats;
 import com.google.common.primitives.Ints;
 import com.google.common.primitives.Longs;
 import com.google.common.primitives.Shorts;
+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 tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
@@ -384,4 +386,60 @@ final class PrimitiveRules {
       return Double.isFinite(d);
     }
   }
+
+  /** Prefer an {@link Integer#signum(int)} comparison to 1 over less clear alternatives. */
+  static final class IntegerSignumIsPositive {
+    @BeforeTemplate
+    boolean before(int i) {
+      return Refaster.anyOf(Integer.signum(i) > 0, Integer.signum(i) >= 1);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(int i) {
+      return Integer.signum(i) == 1;
+    }
+  }
+
+  /** Prefer an {@link Integer#signum(int)} comparison to -1 over less clear alternatives. */
+  static final class IntegerSignumIsNegative {
+    @BeforeTemplate
+    boolean before(int i) {
+      return Refaster.anyOf(Integer.signum(i) < 0, Integer.signum(i) <= -1);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(int i) {
+      return Integer.signum(i) == -1;
+    }
+  }
+
+  /** Prefer an {@link Long#signum(long)} comparison to 1 over less clear alternatives. */
+  static final class LongSignumIsPositive {
+    @BeforeTemplate
+    boolean before(long l) {
+      return Refaster.anyOf(Long.signum(l) > 0, Long.signum(l) >= 1);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(long l) {
+      return Long.signum(l) == 1;
+    }
+  }
+
+  /** Prefer an {@link Long#signum(long)} comparison to -1 over less clear alternatives. */
+  static final class LongSignumIsNegative {
+    @BeforeTemplate
+    boolean before(long l) {
+      return Refaster.anyOf(Long.signum(l) < 0, Long.signum(l) <= -1);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(long l) {
+      return Long.signum(l) == -1;
+    }
+  }
 }

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

@@ -5,18 +5,23 @@ import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.MoreCollectors.toOptional;
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 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.stream.Collectors.maxBy;
+import static java.util.stream.Collectors.minBy;
 import static java.util.stream.Collectors.toCollection;
 import static org.assertj.core.api.Assertions.assertThat;
 import static reactor.function.TupleUtils.function;
 
 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;
+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;
@@ -25,8 +30,8 @@ import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Comparator;
-import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.Callable;
 import java.util.function.BiConsumer;
@@ -40,6 +45,7 @@ import org.jspecify.annotations.Nullable;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
+import reactor.math.MathFlux;
 import reactor.test.StepVerifier;
 import reactor.test.publisher.PublisherProbe;
 import reactor.util.context.Context;
@@ -47,6 +53,8 @@ import reactor.util.function.Tuple2;
 import tech.picnic.errorprone.refaster.annotation.Description;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 import tech.picnic.errorprone.refaster.annotation.Severity;
+import tech.picnic.errorprone.refaster.matchers.IsEmpty;
+import tech.picnic.errorprone.refaster.matchers.IsIdentityOperation;
 import tech.picnic.errorprone.refaster.matchers.ThrowsCheckedException;
 
 /** Refaster rules related to Reactor expressions and statements. */
@@ -97,7 +105,7 @@ final class ReactorRules {
   }
 
   /** Prefer {@link Mono#justOrEmpty(Object)} over more contrived alternatives. */
-  static final class MonoJustOrEmptyObject<@Nullable T> {
+  static final class MonoJustOrEmptyObject<T extends @Nullable Object> {
     @BeforeTemplate
     Mono<T> before(T value) {
       return Mono.justOrEmpty(Optional.ofNullable(value));
@@ -246,11 +254,43 @@ 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 +367,10 @@ 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 +433,74 @@ 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(
+        Function<? super Object[], ? extends T> combinator,
+        int prefetch,
+        Comparator<? super T> comparator) {
+      return Refaster.anyOf(
+          Flux.zip(combinator),
+          Flux.zip(combinator, prefetch),
+          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));
+    }
+
+    @BeforeTemplate
+    Flux<T> before(Function<Object[], T> combinator, int prefetch) {
+      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
@@ -400,22 +511,37 @@ 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
-    // `Stream#map`, `Mono#map` and `Flux#map`.
+    // `Stream#map`, `Mono#map` and `Flux#map`. Alternatively, extend the `IsIdentityOperation`
+    // matcher and use it to constrain the matched `map` argument.
     @BeforeTemplate
     Mono<ImmutableList<T>> before3(Mono<ImmutableList<T>> mono) {
       return mono.map(ImmutableList::copyOf);
     }
 
     @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
@@ -424,57 +550,109 @@ final class ReactorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Flux<T> after(Flux<T> flux) {
       return flux;
     }
   }
 
   /** Prefer {@link Flux#concatMap(Function)} over more contrived alternatives. */
-  static final class FluxConcatMap<T, S> {
+  static final class FluxConcatMap<T, S, P extends Publisher<? extends S>> {
     @BeforeTemplate
-    Flux<S> before(Flux<T> flux, Function<? super T, ? extends Publisher<? extends S>> function) {
+    @SuppressWarnings("NestedPublishers")
+    Flux<S> before(
+        Flux<T> flux,
+        Function<? super T, ? extends P> function,
+        @Matches(IsIdentityOperation.class)
+            Function<? super P, ? extends Publisher<? extends S>> identityOperation) {
       return Refaster.anyOf(
           flux.flatMap(function, 1),
           flux.flatMapSequential(function, 1),
-          flux.map(function).concatMap(identity()));
+          flux.map(function).concatMap(identityOperation));
     }
 
     @AfterTemplate
-    Flux<S> after(Flux<T> flux, Function<? super T, ? extends Publisher<? extends S>> function) {
+    Flux<S> after(Flux<T> flux, Function<? super T, ? extends P> function) {
       return flux.concatMap(function);
     }
   }
 
   /** Prefer {@link Flux#concatMap(Function, int)} over more contrived alternatives. */
-  static final class FluxConcatMapWithPrefetch<T, S> {
+  static final class FluxConcatMapWithPrefetch<T, S, P extends Publisher<? extends S>> {
     @BeforeTemplate
+    @SuppressWarnings("NestedPublishers")
     Flux<S> before(
         Flux<T> flux,
-        Function<? super T, ? extends Publisher<? extends S>> function,
-        int prefetch) {
+        Function<? super T, ? extends P> function,
+        int prefetch,
+        @Matches(IsIdentityOperation.class)
+            Function<? super P, ? extends Publisher<? extends S>> identityOperation) {
       return Refaster.anyOf(
           flux.flatMap(function, 1, prefetch),
           flux.flatMapSequential(function, 1, prefetch),
-          flux.map(function).concatMap(identity(), prefetch));
+          flux.map(function).concatMap(identityOperation, prefetch));
     }
 
     @AfterTemplate
-    Flux<S> after(
-        Flux<T> flux,
-        Function<? super T, ? extends Publisher<? extends S>> function,
-        int prefetch) {
+    Flux<S> after(Flux<T> flux, Function<? super T, ? extends P> function, int prefetch) {
       return flux.concatMap(function, prefetch);
     }
   }
 
-  /**
-   * Prefer {@link Flux#concatMapIterable(Function)} over {@link Flux#flatMapIterable(Function)}, as
-   * the former has equivalent semantics but a clearer name.
-   */
-  static final class FluxConcatMapIterable<T, S> {
+  /** Avoid contrived alternatives to {@link Mono#flatMapIterable(Function)}. */
+  static final class MonoFlatMapIterable<T, S, I extends Iterable<? extends S>> {
     @BeforeTemplate
-    Flux<S> before(Flux<T> flux, Function<? super T, ? extends Iterable<? extends S>> function) {
-      return flux.flatMapIterable(function);
+    Flux<S> before(Mono<T> mono, Function<? super T, I> function) {
+      return mono.map(function).flatMapMany(Flux::fromIterable);
+    }
+
+    @BeforeTemplate
+    Flux<S> before(
+        Mono<T> mono,
+        Function<? super T, I> function,
+        @Matches(IsIdentityOperation.class)
+            Function<? super I, ? extends Iterable<? extends S>> identityOperation) {
+      return Refaster.anyOf(
+          mono.map(function).flatMapIterable(identityOperation),
+          mono.flux().concatMapIterable(function));
+    }
+
+    @AfterTemplate
+    Flux<S> after(Mono<T> mono, Function<? super T, I> function) {
+      return mono.flatMapIterable(function);
+    }
+  }
+
+  /**
+   * 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, I extends Iterable<? extends S>> {
+    @BeforeTemplate
+    Flux<S> before(
+        Flux<T> flux,
+        Function<? super T, I> function,
+        @Matches(IsIdentityOperation.class)
+            Function<? super I, ? extends Iterable<? extends S>> identityOperation) {
+      return Refaster.anyOf(
+          flux.flatMapIterable(function), flux.map(function).concatMapIterable(identityOperation));
     }
 
     @AfterTemplate
@@ -484,14 +662,20 @@ 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> {
+  static final class FluxConcatMapIterableWithPrefetch<T, S, I extends Iterable<? extends S>> {
     @BeforeTemplate
     Flux<S> before(
-        Flux<T> flux, Function<? super T, ? extends Iterable<? extends S>> function, int prefetch) {
-      return flux.flatMapIterable(function, prefetch);
+        Flux<T> flux,
+        Function<? super T, I> function,
+        int prefetch,
+        @Matches(IsIdentityOperation.class)
+            Function<? super I, ? extends Iterable<? extends S>> identityOperation) {
+      return Refaster.anyOf(
+          flux.flatMapIterable(function, prefetch),
+          flux.map(function).concatMapIterable(identityOperation, prefetch));
     }
 
     @AfterTemplate
@@ -544,6 +728,27 @@ final class ReactorRules {
     }
   }
 
+  /**
+   * Prefer {@link Mono#map(Function)} over alternatives that unnecessarily create and collect a
+   * {@link Flux}.
+   */
+  // XXX: This rule assumes that any matched `Collector` does not filter or reorder elements after
+  // application of the matched `Function`.
+  // XXX: The `function` parameter is not matched, unless `I` is changed to `Iterable<? extends S>`,
+  // which would make the rule incorrect.
+  static final class MonoMapToIterable<T, S, I extends Iterable<? extends S>> {
+    @BeforeTemplate
+    Mono<I> before(
+        Mono<T> mono, Function<? super T, ? extends I> function, Collector<S, ?, I> collector) {
+      return mono.flatMapIterable(function).collect(collector);
+    }
+
+    @AfterTemplate
+    Mono<I> after(Mono<T> mono, Function<? super T, ? extends I> function) {
+      return mono.map(function);
+    }
+  }
+
   /**
    * Prefer {@link Flux#map(Function)} over alternatives that unnecessarily require an inner
    * subscription.
@@ -553,7 +758,7 @@ final class ReactorRules {
     abstract S transformation(@MayOptionallyUse T value);
 
     @BeforeTemplate
-    Flux<S> before(Flux<T> flux, boolean delayUntilEnd, int maxConcurrency, int prefetch) {
+    Flux<S> before(Flux<T> flux, int prefetch, boolean delayUntilEnd, int maxConcurrency) {
       return Refaster.anyOf(
           flux.concatMap(x -> Mono.just(transformation(x))),
           flux.concatMap(x -> Flux.just(transformation(x))),
@@ -621,7 +826,7 @@ final class ReactorRules {
 
     @BeforeTemplate
     @SuppressWarnings("java:S138" /* Method is long, but not complex. */)
-    Publisher<S> before(Flux<T> flux, boolean delayUntilEnd, int maxConcurrency, int prefetch) {
+    Publisher<S> before(Flux<T> flux, int prefetch, boolean delayUntilEnd, int maxConcurrency) {
       return Refaster.anyOf(
           flux.concatMap(
               x ->
@@ -723,7 +928,7 @@ 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
@@ -732,15 +937,141 @@ 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 operations prior to invocation of {@link Mono#thenMany(Publisher)}. */
+  static final class MonoThenMany<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Mono<T> mono, Publisher<S> publisher) {
+      return Refaster.anyOf(
+          mono.ignoreElement().thenMany(publisher), mono.flux().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 operations prior to invocation of {@link Mono#then(Mono)}. */
+  static final class MonoThenMono<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Mono<T> mono1, Mono<S> mono2) {
+      return Refaster.anyOf(mono1.ignoreElement().then(mono2), mono1.flux().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.
+  // XXX: The `mono.transform(Mono::singleOptional)` replacement is a special case of a more general
+  // rule. Consider introducing an Error Prone check for this.
   static final class MonoSingleOptional<T> {
     @BeforeTemplate
     Mono<Optional<T>> before(Mono<T> mono) {
       return Refaster.anyOf(
           mono.flux().collect(toOptional()),
-          mono.map(Optional::of).defaultIfEmpty(Optional.empty()));
+          mono.map(Optional::of).defaultIfEmpty(Optional.empty()),
+          mono.transform(Mono::singleOptional));
     }
 
     @AfterTemplate
@@ -776,28 +1107,84 @@ final class ReactorRules {
     }
   }
 
-  /** Prefer {@link Mono#flatMap(Function)} over more contrived alternatives. */
-  static final class MonoFlatMap<S, T> {
+  /** Prefer {@link Mono#ofType(Class)} over more contrived alternatives. */
+  static final class MonoOfType<T, S> {
     @BeforeTemplate
-    Mono<T> before(Mono<S> mono, Function<? super S, ? extends Mono<? extends T>> function) {
-      return mono.map(function).flatMap(identity());
+    Mono<S> before(Mono<T> mono, Class<S> clazz) {
+      return mono.filter(clazz::isInstance).cast(clazz);
     }
 
     @AfterTemplate
-    Mono<T> after(Mono<S> mono, Function<? super S, ? extends Mono<? extends T>> function) {
+    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, P extends Mono<? extends T>> {
+    @BeforeTemplate
+    @SuppressWarnings("NestedPublishers")
+    Mono<T> before(
+        Mono<S> mono,
+        Function<? super S, ? extends P> function,
+        @Matches(IsIdentityOperation.class)
+            Function<? super P, ? extends Mono<? extends T>> identityOperation) {
+      return mono.map(function).flatMap(identityOperation);
+    }
+
+    @AfterTemplate
+    Mono<T> after(Mono<S> mono, Function<? super S, ? extends P> function) {
       return mono.flatMap(function);
     }
   }
 
   /** Prefer {@link Mono#flatMapMany(Function)} over more contrived alternatives. */
-  static final class MonoFlatMapMany<S, T> {
+  static final class MonoFlatMapMany<S, T, P extends Publisher<? extends 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, P> function,
+        @Matches(IsIdentityOperation.class)
+            Function<? super P, ? extends Publisher<? extends T>> identityOperation,
+        int prefetch,
+        boolean delayUntilEnd,
+        int maxConcurrency) {
+      return Refaster.anyOf(
+          mono.map(function).flatMapMany(identityOperation),
+          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
-    Flux<T> after(Mono<S> mono, Function<? super S, ? extends Publisher<? extends T>> function) {
+    Flux<T> after(Mono<S> mono, Function<? super S, ? extends P> function) {
       return mono.flatMapMany(function);
     }
   }
@@ -1177,6 +1564,22 @@ 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.
@@ -1211,13 +1614,134 @@ final class ReactorRules {
     }
   }
 
+  /** Prefer {@link Flux#sort()} over more verbose alternatives. */
+  static final class FluxSort<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Flux<T> before(Flux<T> flux) {
+      return flux.sort(naturalOrder());
+    }
+
+    @AfterTemplate
+    Flux<T> after(Flux<T> flux) {
+      return flux.sort();
+    }
+  }
+
+  /** Prefer {@link MathFlux#min(Publisher)} over less efficient alternatives. */
+  static final class FluxTransformMin<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Mono<T> before(Flux<T> flux) {
+      return flux.sort().next();
+    }
+
+    @AfterTemplate
+    Mono<T> after(Flux<T> flux) {
+      return flux.transform(MathFlux::min).singleOrEmpty();
+    }
+  }
+
+  /**
+   * Prefer {@link MathFlux#min(Publisher, Comparator)} over less efficient or more verbose
+   * alternatives.
+   */
+  static final class FluxTransformMinWithComparator<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Mono<T> before(Flux<T> flux, Comparator<? super T> cmp) {
+      return Refaster.anyOf(
+          flux.sort(cmp).next(), flux.collect(minBy(cmp)).flatMap(Mono::justOrEmpty));
+    }
+
+    @AfterTemplate
+    Mono<T> after(Flux<T> flux, Comparator<? super T> cmp) {
+      return flux.transform(f -> MathFlux.min(f, cmp)).singleOrEmpty();
+    }
+  }
+
+  /** Prefer {@link MathFlux#max(Publisher)} over less efficient alternatives. */
+  static final class FluxTransformMax<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Mono<T> before(Flux<T> flux) {
+      return flux.sort().last();
+    }
+
+    @AfterTemplate
+    Mono<T> after(Flux<T> flux) {
+      return flux.transform(MathFlux::max).singleOrEmpty();
+    }
+  }
+
+  /**
+   * Prefer {@link MathFlux#max(Publisher, Comparator)} over less efficient or more verbose
+   * alternatives.
+   */
+  static final class FluxTransformMaxWithComparator<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Mono<T> before(Flux<T> flux, Comparator<? super T> cmp) {
+      return Refaster.anyOf(
+          flux.sort(cmp).last(), flux.collect(maxBy(cmp)).flatMap(Mono::justOrEmpty));
+    }
+
+    @AfterTemplate
+    Mono<T> after(Flux<T> flux, Comparator<? super T> cmp) {
+      return flux.transform(f -> MathFlux.max(f, cmp)).singleOrEmpty();
+    }
+  }
+
+  /** Prefer {@link MathFlux#min(Publisher)} over more contrived alternatives. */
+  static final class MathFluxMin<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Mono<T> before(Publisher<T> publisher) {
+      return Refaster.anyOf(
+          MathFlux.min(publisher, naturalOrder()), MathFlux.max(publisher, reverseOrder()));
+    }
+
+    @AfterTemplate
+    Mono<T> after(Publisher<T> publisher) {
+      return MathFlux.min(publisher);
+    }
+  }
+
+  /** Prefer {@link MathFlux#max(Publisher)} over more contrived alternatives. */
+  static final class MathFluxMax<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    Mono<T> before(Publisher<T> publisher) {
+      return Refaster.anyOf(
+          MathFlux.min(publisher, reverseOrder()), MathFlux.max(publisher, naturalOrder()));
+    }
+
+    @AfterTemplate
+    Mono<T> after(Publisher<T> publisher) {
+      return MathFlux.max(publisher);
+    }
+  }
+
+  /**
+   * Prefer {@link Flux#singleOrEmpty()} over {@link Flux#next()} when the {@link Flux} emits at
+   * most one element.
+   */
+  // XXX: This is a special case of a more general rule. Consider introducing an Error Prone check
+  // for this.
+  // XXX: The `transformer` parameter isn't matched, unless the signature is changed to `? extends
+  // Publisher<S>`, which would make the rule incorrect.
+  static final class FluxTransformToMonoSingleOrEmpty<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Flux<T> flux, Function<? super Flux<T>, ? extends Mono<S>> transformer) {
+      return flux.transform(transformer).next();
+    }
+
+    @AfterTemplate
+    Mono<S> after(Flux<T> flux, Function<? super Flux<T>, ? extends Mono<S>> transformer) {
+      return flux.transform(transformer).singleOrEmpty();
+    }
+  }
+
   /** Prefer {@link reactor.util.context.Context#empty()}} over more verbose alternatives. */
-  // XXX: Consider introducing an `IsEmpty` matcher that identifies a wide range of guaranteed-empty
-  // `Collection` and `Map` expressions.
+  // XXX: Introduce Refaster rules or a `BugChecker` that maps `(Immutable)Map.of(k, v)` to
+  // `Context.of(k, v)` and likewise for multi-pair overloads.
   static final class ContextEmpty {
     @BeforeTemplate
-    Context before() {
-      return Context.of(Refaster.anyOf(new HashMap<>(), ImmutableMap.of()));
+    Context before(@Matches(IsEmpty.class) Map<?, ?> map) {
+      return Context.of(map);
     }
 
     @AfterTemplate
@@ -1243,7 +1767,7 @@ final class ReactorRules {
   static final class StepVerifierFromMono<T> {
     @BeforeTemplate
     StepVerifier.FirstStep<? extends T> before(Mono<T> mono) {
-      return StepVerifier.create(mono);
+      return Refaster.anyOf(StepVerifier.create(mono), mono.flux().as(StepVerifier::create));
     }
 
     @AfterTemplate
@@ -1266,16 +1790,17 @@ final class ReactorRules {
   }
 
   /** Don't unnecessarily have {@link StepVerifier.Step} expect no elements. */
-  // XXX: Given an `IsEmpty` matcher that identifies a wide range of guaranteed-empty `Iterable`
-  // expressions, consider also simplifying `step.expectNextSequence(someEmptyIterable)`.
   static final class StepVerifierStepIdentity<T> {
     @BeforeTemplate
     @SuppressWarnings("unchecked")
-    StepVerifier.Step<T> before(StepVerifier.Step<T> step) {
-      return Refaster.anyOf(step.expectNext(), step.expectNextCount(0));
+    StepVerifier.Step<T> before(
+        StepVerifier.Step<T> step, @Matches(IsEmpty.class) Iterable<? extends T> iterable) {
+      return Refaster.anyOf(
+          step.expectNext(), step.expectNextCount(0), step.expectNextSequence(iterable));
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     StepVerifier.Step<T> after(StepVerifier.Step<T> step) {
       return step;
     }
@@ -1295,6 +1820,23 @@ 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, T object, Collector<? super T, ?, L> listCollector) {
+      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 +1869,7 @@ 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

@@ -19,13 +19,17 @@ 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 +45,14 @@ 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.IsIdentityOperation;
 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;
     }
@@ -352,6 +357,8 @@ final class StreamRules {
           stream.filter(predicate).findAny().isEmpty());
     }
 
+    // XXX: Consider extending `@Matches(IsIdentityOperation.class)` such that it can replace this
+    // template's `Refaster.anyOf` usage.
     @BeforeTemplate
     boolean before2(
         Stream<T> stream,
@@ -390,6 +397,8 @@ final class StreamRules {
           !stream.noneMatch(predicate), stream.filter(predicate).findAny().isPresent());
     }
 
+    // XXX: Consider extending `@Matches(IsIdentityOperation.class)` such that it can replace this
+    // template's `Refaster.anyOf` usage.
     @BeforeTemplate
     boolean before2(
         Stream<T> stream,
@@ -410,6 +419,8 @@ final class StreamRules {
       return stream.noneMatch(Refaster.anyOf(not(predicate), predicate.negate()));
     }
 
+    // XXX: Consider extending `@Matches(IsIdentityOperation.class)` such that it can replace this
+    // template's `Refaster.anyOf` usage.
     @BeforeTemplate
     boolean before2(
         Stream<T> stream,
@@ -624,4 +635,117 @@ final class StreamRules {
       return stream.flatMap(mapper).collect(collector);
     }
   }
+
+  static final class StreamsConcat<T> {
+    @BeforeTemplate
+    Stream<T> before(
+        @Repeated Stream<T> stream,
+        @Matches(IsIdentityOperation.class)
+            Function<? super Stream<T>, ? extends Stream<? extends T>> mapper) {
+      return Stream.of(Refaster.asVarargs(stream)).flatMap(mapper);
+    }
+
+    @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);
+    }
+  }
 }