Introduce ReturnValueUnused matcher for Refaster use

WIP:
1. As-is this isn't actually useful, because currently there's no way to
   express that a certain matcher should apply to a whole expression
   (rather than just a "free variable"/template parameter).
2. There are some XXXes.
3. Assuming (1) is resolved somehow, we should add at least one Refaster
   template demonstrating how this is used. Example transformation we'd
   want to be able to do in case the expression's return value is
   ignored: `flux.blockLast()` -> `flux.then().block()`.

.github/ISSUE_TEMPLATE/bug_report.md

@@ -42,9 +42,9 @@ 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. `17.0.3`).
-- Error Prone version (e.g. `2.15.0`).
-- Error Prone Support version (e.g. `0.3.0`).
+- 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`).
 
 ### Additional context
 

.github/workflows/build.yml

@@ -10,38 +10,32 @@ jobs:
     strategy:
       matrix:
         os: [ ubuntu-22.04 ]
-        jdk: [ 11.0.16, 17.0.4, 19 ]
+        jdk: [ 11.0.20, 17.0.8, 21.0.0 ]
         distribution: [ temurin ]
         experimental: [ false ]
         include:
-          - os: macos-12
-            jdk: 17.0.4
+          - os: macos-14
+            jdk: 17.0.8
             distribution: temurin
             experimental: false
           - os: windows-2022
-            jdk: 17.0.4
+            jdk: 17.0.8
             distribution: temurin
             experimental: false
-          - os: ubuntu-22.04
-            jdk: 20-ea
-            distribution: zulu
-            experimental: true
     runs-on: ${{ matrix.os }}
     continue-on-error: ${{ matrix.experimental }}
     steps:
-        # We run the build twice for each supported JDK: once against the
-        # original Error Prone release, using only Error Prone checks available
-        # on Maven Central, and once against the Picnic Error Prone fork,
-        # additionally enabling all checks defined in this project and any
-        # Error Prone checks available only from other artifact repositories.
-      - name: Check out code
-        uses: actions/checkout@v3.1.0
-      - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
+      # We run the build twice for each supported JDK: once against the
+      # original Error Prone release, using only Error Prone checks available
+      # on Maven Central, and once against the Picnic Error Prone fork,
+      # additionally enabling all checks defined in this project and any Error
+      # Prone checks available only from other artifact repositories.
+      - name: Check out code 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
@@ -52,4 +46,3 @@ jobs:
         run: mvn build-helper:remove-project-artifact
 
 # XXX: Enable Codecov once we "go public".
-# XXX: Enable SonarCloud once we "go public".

.github/workflows/codeql.yml

@@ -0,0 +1,40 @@
+# Analyzes the code using GitHub's default CodeQL query database.
+# Identified issues are registered with GitHub's code scanning dashboard. When
+# a pull request is analyzed, any offending lines are annotated. See
+# https://codeql.github.com for details.
+name: CodeQL analysis
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+  schedule:
+    - cron: '0 4 * * 1'
+permissions:
+  contents: read
+jobs:
+  analyze:
+    strategy:
+      matrix:
+        language: [ java, ruby ]
+    permissions:
+      contents: read
+      security-events: write
+    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:
+          java-version: 17.0.8
+          java-distribution: temurin
+          maven-version: 3.9.6
+      - name: Initialize CodeQL
+        uses: github/codeql-action/init@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
+        with:
+          languages: ${{ matrix.language }}
+      - name: Perform minimal build
+        if: matrix.language == 'java'
+        run: mvn -T1C clean package -DskipTests -Dverification.skip
+      - name: Perform CodeQL analysis
+        uses: github/codeql-action/analyze@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
+        with:
+          category: /language:${{ matrix.language }}

.github/workflows/deploy-website.yml

@@ -3,22 +3,24 @@ on:
   pull_request:
   push:
     branches: [ master, website ]
+permissions:
+  contents: read
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
 jobs:
   build:
-    permissions:
-      contents: read
     runs-on: ubuntu-22.04
     steps:
       - name: Check out code
-        uses: actions/checkout@v3.1.0
-      - uses: ruby/setup-ruby@v1.126.0
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          persist-credentials: false
+      - 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
@@ -30,7 +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:
@@ -46,4 +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

@@ -0,0 +1,36 @@
+# Analyzes the code base and GitHub project configuration for adherence to
+# security best practices for open source software. Identified issues are
+# registered with GitHub's code scanning dashboard. When a pull request is
+# analyzed, any offending lines are annotated. See
+# https://securityscorecards.dev for details.
+name: OpenSSF Scorecard update
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+  schedule:
+    - cron: '0 4 * * 1'
+permissions:
+  contents: read
+jobs:
+  analyze:
+    permissions:
+      contents: read
+      security-events: write
+      id-token: write
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Check out code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          persist-credentials: false
+      - name: Run OpenSSF Scorecard analysis
+        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@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
+        with:
+          sarif_file: results.sarif

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

@@ -11,16 +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
-      - name: Set up JDK
-        uses: actions/setup-java@v3.8.0
-        with:
-          java-version: 17.0.4
-          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
@@ -31,7 +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

@@ -9,24 +9,24 @@ on:
       - completed
 permissions:
   actions: read
-  checks: write
-  contents: read
-  pull-requests: write
 jobs:
   update-pr:
     if: ${{ github.event.workflow_run.conclusion == 'success' }}
+    permissions:
+      actions: read
+      checks: write
+      contents: read
+      pull-requests: write
     runs-on: ubuntu-22.04
     steps:
-      - name: Check out code
-        uses: actions/checkout@v3.1.0
-      - 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: 17.0.4
-          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

@@ -0,0 +1,35 @@
+# Analyzes the code base using SonarCloud. See
+# https://sonarcloud.io/project/overview?id=PicnicSupermarket_error-prone-support.
+name: SonarCloud analysis
+on:
+  pull_request:
+  push:
+    branches: [ master ]
+  schedule:
+    - cron: '0 4 * * 1'
+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 and set up JDK and Maven
+        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+        with:
+          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
+      - name: Perform SonarCloud analysis
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+          SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
+        run: mvn -T1C jacoco:prepare-agent verify jacoco:report sonar:sonar -Dverification.skip -Dsonar.projectKey=PicnicSupermarket_error-prone-support

.gitignore

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

.mvn/maven.config

@@ -1 +1,3 @@
---batch-mode --errors --strict-checksums
+--batch-mode
+--errors
+--strict-checksums

.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

@@ -48,6 +48,17 @@ be accepted. When in doubt, make sure to first raise an
 
 To the extent possible, the pull request process guards our coding guidelines.
 Some pointers:
+- Try to make sure that the
+  [`./run-full-build.sh`][error-prone-support-full-build] script completes
+  successfully, ideally before opening a pull request. See the [development
+  instructions][error-prone-support-developing] for details on how to
+  efficiently resolve many of the errors and warnings that may be reported. (In
+  particular, make sure to run `mvn fmt:format` and
+  [`./apply-error-prone-suggestions.sh`][error-prone-support-patch].) That
+  said, if you feel that the build fails for invalid or debatable reasons, or
+  if you're unsure how to best resolve an issue, don't let that discourage you
+  from opening a PR with a failing build; we can have a look at the issue
+  together!
 - Checks should be _topical_: ideally they address a single concern.
 - Where possible checks should provide _fixes_, and ideally these are
   completely behavior-preserving. In order for a check to be adopted by users
@@ -66,6 +77,9 @@ Some pointers:
   sneak in unrelated changes; instead just open more than one pull request 😉.
 
 [error-prone-criteria]: https://errorprone.info/docs/criteria
+[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

@@ -15,13 +15,26 @@ 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]
+[![OpenSSF Best Practices][openssf-best-practices-badge]][openssf-best-practices-checklist]
+[![OpenSSF Scorecard][openssf-scorecard-badge]][openssf-scorecard-report]
+[![CodeQL Analysis][codeql-badge]][codeql-master]
 [![GitHub Actions][github-actions-build-badge]][github-actions-build-master]
+[![Mutation tested with PIT][pitest-badge]][pitest]
+[![Quality Gate Status][sonarcloud-quality-badge]][sonarcloud-quality-master]
+[![Maintainability Rating][sonarcloud-maintainability-badge]][sonarcloud-maintainability-master]
+[![Reliability Rating][sonarcloud-reliability-badge]][sonarcloud-reliability-master]
+[![Security Rating][sonarcloud-security-badge]][sonarcloud-security-master]
+[![Coverage][sonarcloud-coverage-badge]][sonarcloud-coverage-master]
+[![Duplicated Lines (%)][sonarcloud-duplication-badge]][sonarcloud-duplication-master]
+[![Technical Debt][sonarcloud-technical-debt-badge]][sonarcloud-technical-debt-master]
 [![License][license-badge]][license]
 [![PRs Welcome][pr-badge]][contributing]
 
@@ -36,7 +49,9 @@ code_][picnic-blog-ep-post].
 ### Installation
 
 This library is built on top of [Error Prone][error-prone-orig-repo]. To use
-it:
+it, read the installation guide for Maven or Gradle below.
+
+#### Maven
 
 1. First, follow Error Prone's [installation
    guide][error-prone-installation-guide].
@@ -50,6 +65,8 @@ it:
                <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. -->
@@ -79,8 +96,6 @@ it:
                            </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>
@@ -94,6 +109,32 @@ it:
 Prone Support. Alternatively reference this project's `self-check` profile
 definition. -->
 
+#### Gradle
+
+1. First, follow the [installation
+   guide][error-prone-gradle-installation-guide] of the
+   `gradle-errorprone-plugin`.
+2. Next, edit your `build.gradle` file to add one or more Error Prone Support
+   modules:
+
+   ```groovy
+   dependencies {
+       // Error Prone itself.
+       errorprone("com.google.errorprone:error_prone_core:${errorProneVersion}")
+       // Error Prone Support's additional bug checkers.
+       errorprone("tech.picnic.error-prone-support:error-prone-contrib:${errorProneSupportVersion}")
+       // Error Prone Support's Refaster rules.
+       errorprone("tech.picnic.error-prone-support:refaster-runner:${errorProneSupportVersion}")
+   }
+
+   tasks.withType(JavaCompile).configureEach {
+       options.errorprone.disableWarningsInGeneratedCode = true
+       // Add other Error Prone flags here. See:
+       // - https://github.com/tbroyer/gradle-errorprone-plugin#configuration
+       // - https://errorprone.info/docs/flags
+   }
+   ```
+
 ### Seeing it in action
 
 Consider the following example code:
@@ -144,8 +185,15 @@ rules][refaster-rules].
 ## 👷 Developing Error Prone Support
 
 This is a [Maven][maven] project, so running `mvn clean install` performs a
-full clean build and installs the library to your local Maven repository. Some
-relevant flags:
+full clean build and installs the library to your local Maven repository.
+
+Once you've made changes, the build may fail due to a warning or error emitted
+by static code analysis. The flags and commands listed below allow you to
+suppress or (in a large subset of cases) automatically fix such cases. Make
+sure to carefully check the available options, as this can save you significant
+amounts of development time!
+
+Relevant Maven build parameters:
 
 - `-Dverification.warn` makes the warnings and errors emitted by various
   plugins and the Java compiler non-fatal, where possible.
@@ -162,19 +210,28 @@ relevant flags:
   Pending a release of [google/error-prone#3301][error-prone-pull-3301], this
   flag must currently be used in combination with `-Perror-prone-fork`.
 
-Some other commands one may find relevant:
+Other highly relevant commands:
 
 - `mvn fmt:format` formats the code using
   [`google-java-format`][google-java-format].
-- `./run-mutation-tests.sh` 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].
-- `./apply-error-prone-suggestions.sh` applies Error Prone and Error Prone
-  Support code suggestions to this project. 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-full-build.sh`][script-run-full-build] builds the project twice,
+  where the second pass validates compatbility with Picnic's [Error Prone
+  fork][error-prone-fork-repo] and compliance of the code with any rules
+  defined within this project. (Consider running this before [opening a pull
+  request][contributing-pull-request], as the PR checks also perform this
+  validation.)
+- [`./apply-error-prone-suggestions.sh`][script-apply-error-prone-suggestions]
+  applies Error Prone and Error Prone Support code suggestions to this project.
+  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-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:
@@ -201,17 +258,27 @@ Want to report or fix a bug, suggest or add a new feature, or improve the
 documentation? That's awesome! Please read our [contribution
 guidelines][contributing].
 
+### Security
+
+If you want to report a security vulnerability, please do so through a private
+channel; please see our [security policy][security] for details.
+
 [bug-checks]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/
 [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
 [error-prone-fork-jitpack]: https://jitpack.io/#PicnicSupermarket/error-prone
 [error-prone-fork-repo]: https://github.com/PicnicSupermarket/error-prone
+[error-prone-gradle-installation-guide]: https://github.com/tbroyer/gradle-errorprone-plugin
 [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%3Amaster
+[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
@@ -219,8 +286,13 @@ guidelines][contributing].
 [maven-central-badge]: https://img.shields.io/maven-central/v/tech.picnic.error-prone-support/error-prone-support?color=blue
 [maven-central-search]: https://search.maven.org/artifact/tech.picnic.error-prone-support/error-prone-support
 [maven]: https://maven.apache.org
-[picnic-blog]: https://blog.picnic.nl
+[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://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
 [pitest]: https://pitest.org
 [pitest-maven]: https://pitest.org/quickstart/maven
 [pr-badge]: https://img.shields.io/badge/PRs-welcome-brightgreen.svg
@@ -229,3 +301,22 @@ guidelines][contributing].
 [refaster-rules]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/
 [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
+[sonarcloud-coverage-badge]: https://sonarcloud.io/api/project_badges/measure?project=PicnicSupermarket_error-prone-support&metric=coverage
+[sonarcloud-coverage-master]: https://sonarcloud.io/component_measures?id=PicnicSupermarket_error-prone-support&metric=coverage
+[sonarcloud-duplication-badge]: https://sonarcloud.io/api/project_badges/measure?project=PicnicSupermarket_error-prone-support&metric=duplicated_lines_density
+[sonarcloud-duplication-master]: https://sonarcloud.io/component_measures?id=PicnicSupermarket_error-prone-support&metric=duplicated_lines_density
+[sonarcloud-maintainability-badge]: https://sonarcloud.io/api/project_badges/measure?project=PicnicSupermarket_error-prone-support&metric=sqale_rating
+[sonarcloud-maintainability-master]: https://sonarcloud.io/component_measures?id=PicnicSupermarket_error-prone-support&metric=sqale_rating
+[sonarcloud-quality-badge]: https://sonarcloud.io/api/project_badges/measure?project=PicnicSupermarket_error-prone-support&metric=alert_status
+[sonarcloud-quality-master]: https://sonarcloud.io/summary/new_code?id=PicnicSupermarket_error-prone-support
+[sonarcloud-reliability-badge]: https://sonarcloud.io/api/project_badges/measure?project=PicnicSupermarket_error-prone-support&metric=reliability_rating
+[sonarcloud-reliability-master]: https://sonarcloud.io/component_measures?id=PicnicSupermarket_error-prone-support&metric=reliability_rating
+[sonarcloud-security-badge]: https://sonarcloud.io/api/project_badges/measure?project=PicnicSupermarket_error-prone-support&metric=security_rating
+[sonarcloud-security-master]: https://sonarcloud.io/component_measures?id=PicnicSupermarket_error-prone-support&metric=security_rating
+[sonarcloud-technical-debt-badge]: https://sonarcloud.io/api/project_badges/measure?project=PicnicSupermarket_error-prone-support&metric=sqale_index
+[sonarcloud-technical-debt-master]: https://sonarcloud.io/component_measures?id=PicnicSupermarket_error-prone-support&metric=sqale_index

SECURITY.md

@@ -0,0 +1,23 @@
+# Security policy
+
+We take security seriously. We are mindful of Error Prone Support's place in
+the software supply chain, and the risks and responsibilities that come with
+this.
+
+## Supported versions
+
+This project uses [semantic versioning][semantic-versioning]. In general, only
+the latest version of this software is supported. That said, if users have a
+compelling reason to ask for patch release of an older major release, then we
+will seriously consider such a request. We do urge users to stay up-to-date and
+use the latest release where feasible.
+
+## Reporting a vulnerability
+
+To report a vulnerability, please visit the [security
+advisories][security-advisories] page and click _Report a vulnerability_. We
+will take such reports seriously and work with you to resolve the issue in a
+timely manner.
+
+[security-advisories]: https://github.com/PicnicSupermarket/error-prone-support/security/advisories
+[semantic-versioning]: https://semver.org

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

@@ -0,0 +1,98 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>tech.picnic.error-prone-support</groupId>
+        <artifactId>error-prone-support</artifactId>
+        <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>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_annotation</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_annotations</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_check_api</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_test_helpers</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.fasterxml.jackson.core</groupId>
+            <artifactId>jackson-annotations</artifactId>
+        </dependency>
+        <dependency>
+            <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>
+        </dependency>
+        <dependency>
+            <groupId>com.google.auto.service</groupId>
+            <artifactId>auto-service-annotations</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.google.auto.value</groupId>
+            <artifactId>auto-value-annotations</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.google.guava</groupId>
+            <artifactId>guava</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.assertj</groupId>
+            <artifactId>assertj-core</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jspecify</groupId>
+            <artifactId>jspecify</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <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>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter-params</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+</project>

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

@@ -0,0 +1,147 @@
+package tech.picnic.errorprone.documentation;
+
+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 java.net.URI;
+import java.util.Optional;
+import javax.lang.model.element.AnnotationValue;
+import tech.picnic.errorprone.documentation.BugPatternExtractor.BugPatternDocumentation;
+
+/**
+ * An {@link Extractor} that describes how to extract data from a {@code @BugPattern} annotation.
+ */
+@Immutable
+@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() {}
+
+  @Override
+  public String identifier() {
+    return "bugpattern";
+  }
+
+  @Override
+  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()));
+  }
+
+  /**
+   * Returns the fully-qualified class names of suppression annotations specified by the {@link
+   * BugPattern} annotation located on the given tree.
+   *
+   * @implNote This method cannot simply invoke {@link BugPattern#suppressionAnnotations()}, as that
+   *     will yield an "Attempt to access Class objects for TypeMirrors" exception.
+   */
+  private static ImmutableList<String> getSuppressionAnnotations(ClassTree tree) {
+    AnnotationTree annotationTree =
+        ASTHelpers.getAnnotationWithSimpleName(
+            ASTHelpers.getAnnotations(tree), BugPattern.class.getSimpleName());
+    requireNonNull(annotationTree, "BugPattern annotation must be present");
+
+    Attribute.Array types =
+        doCast(
+            AnnotationMirrors.getAnnotationValue(
+                ASTHelpers.getAnnotationMirror(annotationTree), "suppressionAnnotations"),
+            Attribute.Array.class);
+
+    return types.getValue().stream()
+        .map(v -> doCast(v, Attribute.Class.class).classType.toString())
+        .collect(toImmutableList());
+  }
+
+  @SuppressWarnings("unchecked")
+  private static <T extends AnnotationValue> T doCast(AnnotationValue value, Class<T> target) {
+    verify(target.isInstance(value), "Value '%s' is not of type '%s'", value, target);
+    return (T) value;
+  }
+
+  @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();
+
+    abstract ImmutableList<String> altNames();
+
+    abstract String link();
+
+    abstract ImmutableList<String> tags();
+
+    abstract String summary();
+
+    abstract String explanation();
+
+    abstract SeverityLevel severityLevel();
+
+    abstract boolean canDisable();
+
+    abstract ImmutableList<String> suppressionAnnotations();
+  }
+}

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/DocumentationGenerator.java

@@ -0,0 +1,56 @@
+package tech.picnic.errorprone.documentation;
+
+import static com.google.common.base.Preconditions.checkArgument;
+
+import com.google.auto.service.AutoService;
+import com.google.common.annotations.VisibleForTesting;
+import com.sun.source.util.JavacTask;
+import com.sun.source.util.Plugin;
+import com.sun.tools.javac.api.BasicJavacTask;
+import java.nio.file.InvalidPathException;
+import java.nio.file.Path;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+/**
+ * A compiler {@link Plugin} that analyzes and extracts relevant information for documentation
+ * purposes from processed files.
+ */
+// XXX: Find a better name for this class; it doesn't generate documentation per se.
+@AutoService(Plugin.class)
+public final class DocumentationGenerator implements Plugin {
+  @VisibleForTesting static final String OUTPUT_DIRECTORY_FLAG = "-XoutputDirectory";
+  private static final Pattern OUTPUT_DIRECTORY_FLAG_PATTERN =
+      Pattern.compile(Pattern.quote(OUTPUT_DIRECTORY_FLAG) + "=(.*)");
+
+  /** Instantiates a new {@link DocumentationGenerator} instance. */
+  public DocumentationGenerator() {}
+
+  @Override
+  public String getName() {
+    return getClass().getSimpleName();
+  }
+
+  @Override
+  public void init(JavacTask javacTask, String... args) {
+    checkArgument(args.length == 1, "Precisely one path must be provided");
+
+    javacTask.addTaskListener(
+        new DocumentationGeneratorTaskListener(
+            ((BasicJavacTask) javacTask).getContext(), getOutputPath(args[0])));
+  }
+
+  @VisibleForTesting
+  static Path getOutputPath(String pathArg) {
+    Matcher matcher = OUTPUT_DIRECTORY_FLAG_PATTERN.matcher(pathArg);
+    checkArgument(
+        matcher.matches(), "'%s' must be of the form '%s=<value>'", pathArg, OUTPUT_DIRECTORY_FLAG);
+
+    String path = matcher.group(1);
+    try {
+      return Path.of(path);
+    } catch (InvalidPathException e) {
+      throw new IllegalArgumentException(String.format("Invalid path '%s'", path), e);
+    }
+  }
+}

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

@@ -0,0 +1,92 @@
+package tech.picnic.errorprone.documentation;
+
+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.IOException;
+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;
+
+/**
+ * A {@link TaskListener} that identifies and extracts relevant content for documentation generation
+ * and writes it to disk.
+ */
+// XXX: Find a better name for this class; it doesn't generate documentation per se.
+final class DocumentationGeneratorTaskListener implements TaskListener {
+  @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;
+
+  DocumentationGeneratorTaskListener(Context context, Path path) {
+    this.context = context;
+    this.docsPath = path;
+  }
+
+  @Override
+  public void started(TaskEvent taskEvent) {
+    if (taskEvent.getKind() == Kind.ANALYZE) {
+      createDocsDirectory();
+    }
+  }
+
+  @Override
+  public void finished(TaskEvent taskEvent) {
+    if (taskEvent.getKind() != Kind.ANALYZE) {
+      return;
+    }
+
+    JavaFileObject sourceFile = taskEvent.getSourceFile();
+    CompilationUnitTree compilationUnit = taskEvent.getCompilationUnit();
+    ClassTree classTree = JavacTrees.instance(context).getTree(taskEvent.getTypeElement());
+    if (sourceFile == null || compilationUnit == null || classTree == null) {
+      return;
+    }
+
+    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() {
+    try {
+      Files.createDirectories(docsPath);
+    } catch (IOException e) {
+      throw new IllegalStateException(
+          String.format("Error while creating directory with path '%s'", docsPath), e);
+    }
+  }
+
+  private <T> void writeToFile(String identifier, String className, T data) {
+    Json.write(docsPath.resolve(String.format("%s-%s.json", identifier, className)), data);
+  }
+
+  private static String getSimpleClassName(URI path) {
+    return Paths.get(path).getFileName().toString().replace(".java", "");
+  }
+}

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

@@ -0,0 +1,33 @@
+package tech.picnic.errorprone.documentation;
+
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.annotations.Immutable;
+import com.sun.source.tree.ClassTree;
+import java.util.Optional;
+
+/**
+ * Interface implemented by classes that define how to extract data of some type {@link T} from a
+ * given {@link ClassTree}.
+ *
+ * @param <T> The type of data that is extracted.
+ */
+@Immutable
+interface Extractor<T> {
+  /**
+   * Returns the unique identifier of this extractor.
+   *
+   * @return A non-{@code null} string.
+   */
+  String identifier();
+
+  /**
+   * Attempts to extract an instance of type {@link T} using the provided arguments.
+   *
+   * @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.
+   */
+  Optional<T> tryExtract(ClassTree tree, VisitorState state);
+}

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/main/java/tech/picnic/errorprone/documentation/package-info.java

@@ -0,0 +1,7 @@
+/**
+ * A Java compiler plugin that extracts data from compiled classes, in support of the Error Prone
+ * Support documentation.
+ */
+@com.google.errorprone.annotations.CheckReturnValue
+@org.jspecify.annotations.NullMarked
+package tech.picnic.errorprone.documentation;

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

@@ -0,0 +1,142 @@
+package tech.picnic.errorprone.documentation;
+
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+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 com.google.common.collect.ImmutableList;
+import com.google.errorprone.BugPattern;
+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
+  void noBugPattern(@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 minimalBugPattern(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "MinimalBugChecker.java",
+        "package pkg;",
+        "",
+        "import com.google.errorprone.BugPattern;",
+        "import com.google.errorprone.BugPattern.SeverityLevel;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "@BugPattern(summary = \"MinimalBugChecker summary\", severity = SeverityLevel.ERROR)",
+        "public final class MinimalBugChecker extends BugChecker {}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "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) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "CompleteBugChecker.java",
+        "package pkg;",
+        "",
+        "import com.google.errorprone.BugPattern;",
+        "import com.google.errorprone.BugPattern.SeverityLevel;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "import org.junit.jupiter.api.Test;",
+        "",
+        "@BugPattern(",
+        "    name = \"OtherName\",",
+        "    summary = \"CompleteBugChecker summary\",",
+        "    linkType = BugPattern.LinkType.CUSTOM,",
+        "    link = \"https://error-prone.picnic.tech\",",
+        "    explanation = \"Example explanation\",",
+        "    severity = SeverityLevel.SUGGESTION,",
+        "    altNames = \"Check\",",
+        "    tags = BugPattern.StandardTags.SIMPLIFICATION,",
+        "    disableable = false,",
+        "    suppressionAnnotations = {BugPattern.class, Test.class})",
+        "public final class CompleteBugChecker extends BugChecker {}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "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) {
+    Compilation.compileWithDocumentationGenerator(
+        outputDirectory,
+        "UndocumentedSuppressionBugPattern.java",
+        "package pkg;",
+        "",
+        "import com.google.errorprone.BugPattern;",
+        "import com.google.errorprone.BugPattern.SeverityLevel;",
+        "import com.google.errorprone.bugpatterns.BugChecker;",
+        "",
+        "@BugPattern(",
+        "    summary = \"UndocumentedSuppressionBugPattern summary\",",
+        "    severity = SeverityLevel.WARNING,",
+        "    documentSuppression = false)",
+        "public final class UndocumentedSuppressionBugPattern extends BugChecker {}");
+
+    verifyGeneratedFileContent(
+        outputDirectory,
+        "UndocumentedSuppressionBugPattern",
+        BugPatternDocumentation.create(
+            URI.create("file:///UndocumentedSuppressionBugPattern.java"),
+            "pkg.UndocumentedSuppressionBugPattern",
+            "UndocumentedSuppressionBugPattern",
+            ImmutableList.of(),
+            "",
+            ImmutableList.of(),
+            "UndocumentedSuppressionBugPattern summary",
+            "",
+            WARNING,
+            /* canDisable= */ true,
+            ImmutableList.of()));
+  }
+
+  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

@@ -0,0 +1,74 @@
+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;
+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: 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 path, String... lines) {
+    compileWithDocumentationGenerator(outputDirectory.toAbsolutePath().toString(), path, lines);
+  }
+
+  public static void compileWithDocumentationGenerator(
+      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(
+            "--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,
+                diagnostics::add,
+                options,
+                ImmutableList.of(),
+                ImmutableList.of(javaFileObject));
+
+    Boolean result = task.call();
+    assertThat(diagnostics).isEmpty();
+    assertThat(result).isTrue();
+  }
+}

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

@@ -0,0 +1,140 @@
+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;
+import org.junit.jupiter.api.io.TempDir;
+
+final class DocumentationGeneratorTaskListenerTest {
+  @EnabledOnOs(WINDOWS)
+  @Test
+  void readOnlyFileSystemWindows(@TempDir Path outputDirectory) throws IOException {
+    AclFileAttributeView view =
+        Files.getFileAttributeView(outputDirectory, AclFileAttributeView.class);
+    view.setAcl(
+        view.getAcl().stream()
+            .map(
+                entry ->
+                    AclEntry.newBuilder(entry)
+                        .setPermissions(
+                            Sets.difference(entry.permissions(), ImmutableSet.of(ADD_SUBDIRECTORY)))
+                        .build())
+            .collect(toImmutableList()));
+
+    readOnlyFileSystemFailsToWrite(outputDirectory.resolve("nonexistent"));
+  }
+
+  @DisabledOnOs(WINDOWS)
+  @Test
+  void readOnlyFileSystemNonWindows(@TempDir Path outputDirectory) {
+    assertThat(outputDirectory.toFile().setWritable(false))
+        .describedAs("Failed to make test directory unwritable")
+        .isTrue();
+
+    readOnlyFileSystemFailsToWrite(outputDirectory.resolve("nonexistent"));
+  }
+
+  private static void readOnlyFileSystemFailsToWrite(Path outputDirectory) {
+    assertThatThrownBy(
+            () ->
+                Compilation.compileWithDocumentationGenerator(
+                    outputDirectory, "A.java", "class A {}"))
+        .hasRootCauseInstanceOf(FileSystemException.class)
+        .hasCauseInstanceOf(IllegalStateException.class)
+        .hasMessageEndingWith("Error while creating directory with path '%s'", outputDirectory);
+  }
+
+  @Test
+  void noClassNoOutput(@TempDir Path outputDirectory) {
+    Compilation.compileWithDocumentationGenerator(outputDirectory, "A.java", "package pkg;");
+
+    assertThat(outputDirectory).isEmptyDirectory();
+  }
+
+  @Test
+  void excessArguments(@TempDir Path outputDirectory) {
+    String actualOutputDirectory = outputDirectory.toAbsolutePath() + " extra-arg";
+    assertThatThrownBy(
+            () ->
+                Compilation.compileWithDocumentationGenerator(
+                    actualOutputDirectory, "A.java", "package pkg;"))
+        .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/DocumentationGeneratorTest.java

@@ -0,0 +1,38 @@
+package tech.picnic.errorprone.documentation;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static tech.picnic.errorprone.documentation.DocumentationGenerator.OUTPUT_DIRECTORY_FLAG;
+
+import java.nio.file.InvalidPathException;
+import java.nio.file.Path;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
+
+final class DocumentationGeneratorTest {
+  @ParameterizedTest
+  @ValueSource(strings = {"bar", "foo"})
+  void getOutputPath(String path) {
+    assertThat(DocumentationGenerator.getOutputPath(OUTPUT_DIRECTORY_FLAG + '=' + path))
+        .isEqualTo(Path.of(path));
+  }
+
+  @ParameterizedTest
+  @ValueSource(strings = {"", "-XoutputDirectory", "invalidOption=Test", "nothing"})
+  void getOutputPathWithInvalidArgument(String pathArg) {
+    assertThatThrownBy(() -> DocumentationGenerator.getOutputPath(pathArg))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasMessage("'%s' must be of the form '%s=<value>'", pathArg, OUTPUT_DIRECTORY_FLAG);
+  }
+
+  @Test
+  void getOutputPathWithInvalidPath() {
+    String basePath = "path-with-null-char-\0";
+    assertThatThrownBy(
+            () -> DocumentationGenerator.getOutputPath(OUTPUT_DIRECTORY_FLAG + '=' + basePath))
+        .isInstanceOf(IllegalArgumentException.class)
+        .hasCauseInstanceOf(InvalidPathException.class)
+        .hasMessageEndingWith("Invalid path '%s'", basePath);
+  }
+}

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();
+  }
+}

error-prone-contrib/README.md

@@ -24,7 +24,6 @@ project:
 
 - Document how to apply patches.
 - Document each of the checks.
-- Add [SonarQube][sonarcloud] and [Codecov][codecov] integrations.
 - Add non-Java file formatting support, like we have internally at Picnic.
   (I.e., somehow open-source that stuff.)
 - Auto-generate a website listing each of the checks, just like the Error Prone
@@ -126,9 +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`
@@ -273,7 +269,6 @@ Refaster's expressiveness:
 [autorefactor]: https://autorefactor.org
 [bettercodehub]: https://bettercodehub.com
 [checkstyle-external-project-tests]: https://github.com/checkstyle/checkstyle/blob/master/wercker.yml
-[codecov]: https://codecov.io
 [error-prone-bug-patterns]: https://errorprone.info/bugpatterns
 [error-prone]: https://errorprone.info
 [error-prone-repo]: https://github.com/google/error-prone
@@ -283,4 +278,3 @@ Refaster's expressiveness:
 [main-contributing]: ../CONTRIBUTING.md
 [main-readme]: ../README.md
 [modernizer-maven-plugin]: https://github.com/gaul/modernizer-maven-plugin
-[sonarcloud]: https://sonarcloud.io

error-prone-contrib/pom.xml

@@ -5,13 +5,14 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.7.1-SNAPSHOT</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>
@@ -37,7 +38,19 @@
         <dependency>
             <groupId>${groupId.error-prone}</groupId>
             <artifactId>error_prone_test_helpers</artifactId>
-            <scope>test</scope>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>documentation-support</artifactId>
+            <!-- This dependency is declared only as a hint to Maven that
+            compilation depends on it; see the `maven-compiler-plugin`'s
+            `annotationProcessorPaths` configuration below. -->
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>error-prone-utils</artifactId>
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
@@ -52,11 +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>
@@ -65,19 +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>
@@ -118,6 +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>
@@ -148,6 +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>
@@ -163,6 +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>
@@ -198,6 +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>
@@ -213,6 +259,14 @@
                     <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>${project.groupId}</groupId>
+                                <artifactId>documentation-support</artifactId>
+                                <version>${project.version}</version>
+                            </path>
                             <path>
                                 <groupId>${project.groupId}</groupId>
                                 <artifactId>refaster-compiler</artifactId>
@@ -226,20 +280,10 @@
                         </annotationProcessorPaths>
                         <compilerArgs combine.children="append">
                             <arg>-Xplugin:RefasterRuleCompiler</arg>
+                            <arg>-Xplugin:DocumentationGenerator -XoutputDirectory=${project.build.directory}/docs</arg>
                         </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)
@@ -48,20 +48,18 @@ 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;
     }
 
     /*
      * This is the only `@Autowired` constructor: suggest that it be removed. Note that this likely
-     * 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.
+     * 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
@@ -30,7 +37,7 @@ import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;
 @AutoService(BugChecker.class)
 @BugPattern(
     summary =
-        "Avoid `Collectors.to{List,Map,Set}` in favour of alternatives that emphasize (im)mutability",
+        "Avoid `Collectors.to{List,Map,Set}` in favor of collectors that emphasize (im)mutability",
     link = BUG_PATTERNS_BASE_URL + "CollectorMutability",
     linkType = CUSTOM,
     severity = WARNING,
@@ -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

@@ -0,0 +1,178 @@
+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.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.argument;
+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.returnStatement;
+import static com.google.errorprone.matchers.Matchers.staticMethod;
+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.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.BlockTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.AssignmentTree;
+import com.sun.source.tree.BlockTree;
+import com.sun.source.tree.ExpressionStatementTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.IdentifierTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.ReturnTree;
+import com.sun.source.tree.StatementTree;
+import com.sun.source.tree.Tree;
+import com.sun.source.tree.TryTree;
+import com.sun.source.tree.VariableTree;
+import com.sun.source.util.TreeScanner;
+import com.sun.tools.javac.code.Symbol;
+import java.util.List;
+import java.util.Optional;
+import org.jspecify.annotations.Nullable;
+import tech.picnic.errorprone.utils.MoreASTHelpers;
+import tech.picnic.errorprone.utils.SourceCode;
+
+/**
+ * A {@link BugChecker} that flags unnecessary local variable assignments preceding a return
+ * statement.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Variable assignment is redundant; value can be returned directly",
+    link = BUG_PATTERNS_BASE_URL + "DirectReturn",
+    linkType = CUSTOM,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class DirectReturn extends BugChecker implements BlockTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  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.getCanonicalName())))),
+          staticMethod().onClass("org.mockito.Mockito").namedAnyOf("mock", "spy"));
+
+  /** Instantiates a new {@link DirectReturn} instance. */
+  public DirectReturn() {}
+
+  @Override
+  public Description matchBlock(BlockTree tree, VisitorState state) {
+    List<? extends StatementTree> statements = tree.getStatements();
+    if (statements.size() < 2) {
+      return Description.NO_MATCH;
+    }
+
+    StatementTree finalStatement = statements.get(statements.size() - 1);
+    if (!VARIABLE_RETURN.matches(finalStatement, state)) {
+      return Description.NO_MATCH;
+    }
+
+    Symbol variableSymbol = ASTHelpers.getSymbol(((ReturnTree) finalStatement).getExpression());
+    StatementTree precedingStatement = statements.get(statements.size() - 2);
+
+    return tryMatchAssignment(variableSymbol, precedingStatement)
+        .filter(
+            resultExpr ->
+                canInlineToReturnStatement(resultExpr, state)
+                    && !isIdentifierSymbolReferencedInAssociatedFinallyBlock(variableSymbol, state))
+        .map(
+            resultExpr ->
+                describeMatch(
+                    precedingStatement,
+                    SuggestedFix.builder()
+                        .replace(
+                            precedingStatement,
+                            String.format("return %s;", SourceCode.treeToString(resultExpr, state)))
+                        .delete(finalStatement)
+                        .build()))
+        .orElse(Description.NO_MATCH);
+  }
+
+  private static Optional<ExpressionTree> tryMatchAssignment(Symbol targetSymbol, Tree tree) {
+    if (tree instanceof ExpressionStatementTree) {
+      return tryMatchAssignment(targetSymbol, ((ExpressionStatementTree) tree).getExpression());
+    }
+
+    if (tree instanceof AssignmentTree) {
+      AssignmentTree assignment = (AssignmentTree) tree;
+      return targetSymbol.equals(ASTHelpers.getSymbol(assignment.getVariable()))
+          ? Optional.of(assignment.getExpression())
+          : Optional.empty();
+    }
+
+    if (tree instanceof VariableTree) {
+      VariableTree declaration = (VariableTree) tree;
+      return declaration.getModifiers().getAnnotations().isEmpty()
+              && targetSymbol.equals(ASTHelpers.getSymbol(declaration))
+          ? Optional.ofNullable(declaration.getInitializer())
+          : Optional.empty();
+    }
+
+    return Optional.empty();
+  }
+
+  /**
+   * Tells whether inlining the given expression to the associated return statement can likely be
+   * done without changing the expression's return type.
+   *
+   * <p>Inlining an expression generally does not change its return type, but in rare cases the
+   * operation may have a functional impact. The sole case considered here is the inlining of a
+   * Mockito mock or spy construction without an explicit type. In such a case the type created
+   * depends on context, such as the method's return type.
+   */
+  private static boolean canInlineToReturnStatement(
+      ExpressionTree expressionTree, VisitorState state) {
+    return !MOCKITO_MOCK_OR_SPY_WITH_IMPLICIT_TYPE.matches(expressionTree, state)
+        || MoreASTHelpers.findMethodExitedOnReturn(state)
+            .filter(m -> MoreASTHelpers.areSameType(expressionTree, m.getReturnType(), state))
+            .isPresent();
+  }
+
+  /**
+   * Tells whether the given identifier {@link Symbol} is referenced in a {@code finally} block that
+   * is executed <em>after</em> control flow returns from the {@link VisitorState#getPath() current
+   * location}.
+   */
+  private static boolean isIdentifierSymbolReferencedInAssociatedFinallyBlock(
+      Symbol symbol, VisitorState state) {
+    return Streams.zip(
+            Streams.stream(state.getPath()).skip(1),
+            Streams.stream(state.getPath()),
+            (tree, child) -> {
+              if (!(tree instanceof TryTree)) {
+                return null;
+              }
+
+              BlockTree finallyBlock = ((TryTree) tree).getFinallyBlock();
+              return !child.equals(finallyBlock) ? finallyBlock : null;
+            })
+        .anyMatch(finallyBlock -> referencesIdentifierSymbol(symbol, finallyBlock));
+  }
+
+  private static boolean referencesIdentifierSymbol(Symbol symbol, @Nullable BlockTree tree) {
+    return Boolean.TRUE.equals(
+        new TreeScanner<Boolean, @Nullable Void>() {
+          @Override
+          public Boolean visitIdentifier(IdentifierTree node, @Nullable Void unused) {
+            return symbol.equals(ASTHelpers.getSymbol(node));
+          }
+
+          @Override
+          public Boolean reduce(Boolean r1, Boolean r2) {
+            return Boolean.TRUE.equals(r1) || Boolean.TRUE.equals(r2);
+          }
+        }.scan(tree, null));
+  }
+}

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)
@@ -36,12 +36,15 @@ 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() {}
 
   @Override
+  @SuppressWarnings("java:S1067" /* Chaining disjunctions like this does not impact readability. */)
   public Description matchMethod(MethodTree tree, VisitorState state) {
     if (tree.getBody() == null
         || !tree.getBody().getStatements().isEmpty()

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()))));
@@ -82,10 +82,8 @@ public final class FluxFlatMapUsage extends BugChecker
 
     SuggestedFix serializationFix = SuggestedFixes.renameMethodInvocation(tree, "concatMap", state);
     SuggestedFix concurrencyCapFix =
-        SuggestedFix.builder()
-            .postfixWith(
-                Iterables.getOnlyElement(tree.getArguments()), ", " + MAX_CONCURRENCY_ARG_NAME)
-            .build();
+        SuggestedFix.postfixWith(
+            Iterables.getOnlyElement(tree.getArguments()), ", " + MAX_CONCURRENCY_ARG_NAME);
 
     Description.Builder description = buildDescription(tree);
 

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

@@ -0,0 +1,104 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.common.base.Preconditions.checkState;
+import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
+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.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;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.suppliers.Supplier;
+import com.google.errorprone.suppliers.Suppliers;
+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.Position;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+import tech.picnic.errorprone.utils.ThirdPartyLibrary;
+
+/**
+ * A {@link BugChecker} that flags {@link reactor.core.publisher.Flux} operator usages that may
+ * implicitly cause the calling thread to be blocked.
+ *
+ * <p>Note that the methods flagged here are not themselves blocking, but iterating over the
+ * resulting {@link Iterable} or {@link Stream} may be.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Avoid iterating over `Flux`es in an implicitly blocking manner",
+    link = BUG_PATTERNS_BASE_URL + "FluxImplicitBlock",
+    linkType = CUSTOM,
+    severity = WARNING,
+    tags = {CONCURRENCY, PERFORMANCE})
+public final class FluxImplicitBlock extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> FLUX_WITH_IMPLICIT_BLOCK =
+      instanceMethod()
+          .onDescendantOf("reactor.core.publisher.Flux")
+          .namedAnyOf("toIterable", "toStream")
+          .withNoParameters();
+  private static final Supplier<Type> STREAM =
+      Suppliers.typeFromString(Stream.class.getCanonicalName());
+
+  /** Instantiates a new {@link FluxImplicitBlock} instance. */
+  public FluxImplicitBlock() {}
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!FLUX_WITH_IMPLICIT_BLOCK.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    Description.Builder description =
+        buildDescription(tree).addFix(SuggestedFixes.addSuppressWarnings(state, canonicalName()));
+    if (ThirdPartyLibrary.GUAVA.isIntroductionAllowed(state)) {
+      description.addFix(
+          suggestBlockingElementCollection(
+              tree, ImmutableList.class.getCanonicalName() + ".toImmutableList", state));
+    }
+    description.addFix(
+        suggestBlockingElementCollection(
+            tree, Collectors.class.getCanonicalName() + ".toList", state));
+
+    return description.build();
+  }
+
+  private static SuggestedFix suggestBlockingElementCollection(
+      MethodInvocationTree tree, String fullyQualifiedCollectorMethod, VisitorState state) {
+    SuggestedFix.Builder importSuggestion = SuggestedFix.builder();
+    String replacementMethodInvocation =
+        SuggestedFixes.qualifyStaticImport(fullyQualifiedCollectorMethod, importSuggestion, state);
+
+    boolean isStream =
+        ASTHelpers.isSubtype(ASTHelpers.getResultType(tree), STREAM.get(state), state);
+    String replacement =
+        String.format(
+            ".collect(%s()).block()%s", replacementMethodInvocation, isStream ? ".stream()" : "");
+    return importSuggestion.merge(replaceMethodInvocation(tree, replacement, state)).build();
+  }
+
+  private static SuggestedFix.Builder replaceMethodInvocation(
+      MethodInvocationTree tree, String replacement, VisitorState state) {
+    int startPosition = state.getEndPosition(ASTHelpers.getReceiver(tree));
+    int endPosition = state.getEndPosition(tree);
+
+    checkState(
+        startPosition != Position.NOPOS && endPosition != Position.NOPOS,
+        "Cannot locate method to be replaced in source code");
+
+    return SuggestedFix.builder().replace(startPosition, endPosition, replacement);
+  }
+}

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;
@@ -29,12 +41,16 @@ 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
 // of the identity conversion would cause a different method overload to be selected. Depending on
 // the target method such a modification may change the code's semantics or performance.
+// 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",
@@ -52,24 +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

@@ -8,10 +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.JavaKeywords.isValidIdentifier;
-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;
@@ -25,15 +24,11 @@ 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.ImportTree;
 import com.sun.source.tree.MethodTree;
-import com.sun.source.tree.Tree;
-import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
-import com.sun.tools.javac.code.Type;
 import java.util.Optional;
 import javax.lang.model.element.Modifier;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+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:
@@ -90,7 +85,7 @@ public final class JUnitMethodDeclaration extends BugChecker implements MethodTr
     tryCanonicalizeMethodName(symbol)
         .ifPresent(
             newName ->
-                findMethodRenameBlocker(symbol, newName, state)
+                ConflictDetection.findMethodRenameBlocker(symbol, newName, state)
                     .ifPresentOrElse(
                         blocker -> reportMethodRenameBlocker(tree, blocker, state),
                         () -> fixBuilder.merge(SuggestedFixes.renameMethod(tree, newName, state))));
@@ -106,61 +101,7 @@ public final class JUnitMethodDeclaration extends BugChecker implements MethodTr
             .build());
   }
 
-  /**
-   * If applicable, returns a human-readable argument against assigning the given name to an
-   * existing method.
-   *
-   * <p>This method implements imperfect heuristics. Things it currently does not consider include
-   * the following:
-   *
-   * <ul>
-   *   <li>Whether the rename would merely introduce a method overload, rather than clashing with an
-   *       existing method declaration.
-   *   <li>Whether the rename would cause a method in a superclass to be overridden.
-   *   <li>Whether the rename would in fact clash with a static import. (It could be that a static
-   *       import of the same name is only referenced from lexical scopes in which the method under
-   *       consideration cannot be referenced directly.)
-   * </ul>
-   */
-  private static Optional<String> findMethodRenameBlocker(
-      MethodSymbol method, String newName, VisitorState state) {
-    if (isExistingMethodName(method.owner.type, newName, state)) {
-      return Optional.of(
-          String.format(
-              "a method named `%s` is already defined in this class or a supertype", newName));
-    }
-
-    if (isSimpleNameStaticallyImported(newName, state)) {
-      return Optional.of(String.format("`%s` is already statically imported", newName));
-    }
-
-    if (!isValidIdentifier(newName)) {
-      return Optional.of(String.format("`%s` is not a valid identifier", newName));
-    }
-
-    return Optional.empty();
-  }
-
-  private static boolean isExistingMethodName(Type clazz, String name, VisitorState state) {
-    return ASTHelpers.matchingMethods(state.getName(name), method -> true, clazz, state.getTypes())
-        .findAny()
-        .isPresent();
-  }
-
-  private static boolean isSimpleNameStaticallyImported(String simpleName, VisitorState state) {
-    return state.getPath().getCompilationUnit().getImports().stream()
-        .filter(ImportTree::isStatic)
-        .map(ImportTree::getQualifiedIdentifier)
-        .map(tree -> getStaticImportSimpleName(tree, state))
-        .anyMatch(simpleName::contentEquals);
-  }
-
-  private static CharSequence getStaticImportSimpleName(Tree tree, VisitorState state) {
-    String source = SourceCode.treeToString(tree, state);
-    return source.subSequence(source.lastIndexOf('.') + 1, source.length());
-  }
-
-  private static Optional<String> tryCanonicalizeMethodName(Symbol symbol) {
+  private static Optional<String> tryCanonicalizeMethodName(MethodSymbol symbol) {
     return Optional.of(symbol.getQualifiedName().toString())
         .filter(name -> name.startsWith(TEST_PREFIX))
         .map(name -> name.substring(TEST_PREFIX.length()))

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

@@ -0,0 +1,315 @@
+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.ALL;
+import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.anything;
+import static com.google.errorprone.matchers.Matchers.argument;
+import static com.google.errorprone.matchers.Matchers.argumentCount;
+import static com.google.errorprone.matchers.Matchers.classLiteral;
+import static com.google.errorprone.matchers.Matchers.hasArguments;
+import static com.google.errorprone.matchers.Matchers.isPrimitiveOrBoxedPrimitiveType;
+import static com.google.errorprone.matchers.Matchers.isSameType;
+import static com.google.errorprone.matchers.Matchers.methodHasParameters;
+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.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;
+import com.sun.source.tree.AnnotationTree;
+import com.sun.source.tree.ClassTree;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.LambdaExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.MethodTree;
+import com.sun.source.tree.NewArrayTree;
+import com.sun.source.tree.ReturnTree;
+import com.sun.source.util.TreeScanner;
+import com.sun.tools.javac.code.Type;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Locale;
+import java.util.Optional;
+import java.util.Set;
+import java.util.function.Predicate;
+import java.util.stream.DoubleStream;
+import java.util.stream.IntStream;
+import java.util.stream.LongStream;
+import java.util.stream.Stream;
+import org.jspecify.annotations.Nullable;
+import tech.picnic.errorprone.utils.SourceCode;
+
+/**
+ * A {@link BugChecker} that flags JUnit tests with a {@link
+ * org.junit.jupiter.params.provider.MethodSource} annotation that can be replaced with an
+ * equivalent {@link org.junit.jupiter.params.provider.ValueSource} annotation.
+ */
+// XXX: Where applicable, also flag `@MethodSource` annotations that reference multiple value
+// factory methods (or that repeat the same value factory method multiple times).
+// XXX: Support inlining of overloaded value factory methods.
+// XXX: Support inlining of value factory methods referenced by multiple `@MethodSource`
+// annotations.
+// XXX: Support value factory return expressions of the form `Stream.of(a, b,
+// c).map(Arguments::argument)`.
+// XXX: Support simplification of test methods that accept additional injected parameters such as
+// `TestInfo`; such parameters should be ignored for the purpose of this check.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Prefer `@ValueSource` over a `@MethodSource` where possible and reasonable",
+    linkType = CUSTOM,
+    link = BUG_PATTERNS_BASE_URL + "JUnitValueSource",
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class JUnitValueSource extends BugChecker implements MethodTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> SUPPORTED_VALUE_FACTORY_VALUES =
+      anyOf(
+          isArrayArgumentValueCandidate(),
+          toType(
+              MethodInvocationTree.class,
+              allOf(
+                  staticMethod()
+                      .onClass("org.junit.jupiter.params.provider.Arguments")
+                      .namedAnyOf("arguments", "of"),
+                  argumentCount(1),
+                  argument(0, isArrayArgumentValueCandidate()))));
+  private static final Matcher<ExpressionTree> ARRAY_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS =
+      isSingleDimensionArrayCreationWithAllElementsMatching(SUPPORTED_VALUE_FACTORY_VALUES);
+  private static final Matcher<ExpressionTree> ENUMERATION_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS =
+      toType(
+          MethodInvocationTree.class,
+          allOf(
+              staticMethod()
+                  .onClassAny(
+                      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)));
+  private static final Matcher<MethodTree> IS_UNARY_METHOD_WITH_SUPPORTED_PARAMETER =
+      methodHasParameters(
+          anyOf(
+              isPrimitiveOrBoxedPrimitiveType(),
+              isSameType(String.class),
+              isSameType(state -> state.getSymtab().classType)));
+
+  /** Instantiates a new {@link JUnitValueSource} instance. */
+  public JUnitValueSource() {}
+
+  @Override
+  public Description matchMethod(MethodTree tree, VisitorState state) {
+    if (!IS_UNARY_METHOD_WITH_SUPPORTED_PARAMETER.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    Type parameterType = ASTHelpers.getType(Iterables.getOnlyElement(tree.getParameters()));
+
+    return findMethodSourceAnnotation(tree, state)
+        .flatMap(
+            methodSourceAnnotation ->
+                getSoleLocalFactoryName(methodSourceAnnotation, tree)
+                    .filter(factory -> !hasSiblingReferencingValueFactory(tree, factory, state))
+                    .flatMap(factory -> findSiblingWithName(tree, factory, state))
+                    .flatMap(
+                        factoryMethod ->
+                            tryConstructValueSourceFix(
+                                parameterType, methodSourceAnnotation, factoryMethod, state))
+                    .map(fix -> describeMatch(methodSourceAnnotation, fix)))
+        .orElse(Description.NO_MATCH);
+  }
+
+  /**
+   * Returns the name of the value factory method pointed to by the given {@code @MethodSource}
+   * annotation, if it (a) is the only one and (b) is a method in the same class as the annotated
+   * method.
+   */
+  private static Optional<String> getSoleLocalFactoryName(
+      AnnotationTree methodSourceAnnotation, MethodTree method) {
+    return getElementIfSingleton(getMethodSourceFactoryNames(methodSourceAnnotation, method))
+        .filter(name -> name.indexOf('#') < 0);
+  }
+
+  /**
+   * Tells whether the given method has a sibling method in the same class that depends on the
+   * specified value factory method.
+   */
+  private static boolean hasSiblingReferencingValueFactory(
+      MethodTree tree, String valueFactory, VisitorState state) {
+    return findMatchingSibling(tree, m -> hasValueFactory(m, valueFactory, state), state)
+        .isPresent();
+  }
+
+  private static Optional<MethodTree> findSiblingWithName(
+      MethodTree tree, String methodName, VisitorState state) {
+    return findMatchingSibling(tree, m -> m.getName().contentEquals(methodName), state);
+  }
+
+  private static Optional<MethodTree> findMatchingSibling(
+      MethodTree tree, Predicate<? super MethodTree> predicate, VisitorState state) {
+    return state.findEnclosing(ClassTree.class).getMembers().stream()
+        .filter(MethodTree.class::isInstance)
+        .map(MethodTree.class::cast)
+        .filter(not(tree::equals))
+        .filter(predicate)
+        .findFirst();
+  }
+
+  private static boolean hasValueFactory(
+      MethodTree tree, String valueFactoryMethodName, VisitorState state) {
+    return findMethodSourceAnnotation(tree, state).stream()
+        .anyMatch(
+            annotation ->
+                getMethodSourceFactoryNames(annotation, tree).contains(valueFactoryMethodName));
+  }
+
+  private static Optional<AnnotationTree> findMethodSourceAnnotation(
+      MethodTree tree, VisitorState state) {
+    return HAS_METHOD_SOURCE.multiMatchResult(tree, state).matchingNodes().stream().findFirst();
+  }
+
+  private static Optional<SuggestedFix> tryConstructValueSourceFix(
+      Type parameterType,
+      AnnotationTree methodSourceAnnotation,
+      MethodTree valueFactoryMethod,
+      VisitorState state) {
+    return getSingleReturnExpression(valueFactoryMethod)
+        .flatMap(expression -> tryExtractValueSourceAttributeValue(expression, state))
+        .map(
+            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.
+  private static Optional<ExpressionTree> getSingleReturnExpression(MethodTree methodTree) {
+    List<ExpressionTree> returnExpressions = new ArrayList<>();
+    new TreeScanner<@Nullable Void, @Nullable Void>() {
+      @Override
+      public @Nullable Void visitClass(ClassTree node, @Nullable Void unused) {
+        /* Ignore `return` statements inside anonymous/local classes. */
+        return null;
+      }
+
+      @Override
+      public @Nullable Void visitReturn(ReturnTree node, @Nullable Void unused) {
+        returnExpressions.add(node.getExpression());
+        return super.visitReturn(node, unused);
+      }
+
+      @Override
+      public @Nullable Void visitLambdaExpression(
+          LambdaExpressionTree node, @Nullable Void unused) {
+        /* Ignore `return` statements inside lambda expressions. */
+        return null;
+      }
+    }.scan(methodTree, null);
+
+    return getElementIfSingleton(returnExpressions);
+  }
+
+  private static Optional<String> tryExtractValueSourceAttributeValue(
+      ExpressionTree tree, VisitorState state) {
+    List<? extends ExpressionTree> arguments;
+    if (ENUMERATION_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS.matches(tree, state)) {
+      arguments = ((MethodInvocationTree) tree).getArguments();
+    } else if (ARRAY_OF_SUPPORTED_SINGLE_VALUE_ARGUMENTS.matches(tree, state)) {
+      arguments = ((NewArrayTree) tree).getInitializers();
+    } else {
+      return Optional.empty();
+    }
+
+    /*
+     * Join the values into a comma-separated string, unwrapping `Arguments` factory method
+     * invocations if applicable.
+     */
+    return Optional.of(
+            arguments.stream()
+                .map(
+                    arg ->
+                        arg instanceof MethodInvocationTree
+                            ? Iterables.getOnlyElement(((MethodInvocationTree) arg).getArguments())
+                            : arg)
+                .map(argument -> SourceCode.treeToString(argument, state))
+                .collect(joining(", ")))
+        .map(value -> arguments.size() > 1 ? String.format("{%s}", value) : value);
+  }
+
+  private static String toValueSourceAttributeName(Type type) {
+    String typeString = type.tsym.name.toString();
+
+    switch (typeString) {
+      case "Class":
+        return "classes";
+      case "Character":
+        return "chars";
+      case "Integer":
+        return "ints";
+      default:
+        return typeString.toLowerCase(Locale.ROOT) + 's';
+    }
+  }
+
+  private static <T> Optional<T> getElementIfSingleton(Collection<T> collection) {
+    return Optional.of(collection)
+        .filter(elements -> elements.size() == 1)
+        .map(Iterables::getOnlyElement);
+  }
+
+  private static Matcher<ExpressionTree> isSingleDimensionArrayCreationWithAllElementsMatching(
+      Matcher<? super ExpressionTree> elementMatcher) {
+    return (tree, state) -> {
+      if (!(tree instanceof NewArrayTree)) {
+        return false;
+      }
+
+      NewArrayTree newArray = (NewArrayTree) tree;
+      return newArray.getDimensions().isEmpty()
+          && !newArray.getInitializers().isEmpty()
+          && newArray.getInitializers().stream()
+              .allMatch(element -> elementMatcher.matches(element, state));
+    };
+  }
+
+  private static Matcher<ExpressionTree> isArrayArgumentValueCandidate() {
+    return anyOf(classLiteral(anything()), (tree, state) -> ASTHelpers.constValue(tree) != null);
+  }
+}

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.
@@ -58,6 +59,7 @@ import tech.picnic.errorprone.bugpatterns.util.SourceCode;
     linkType = CUSTOM,
     severity = SUGGESTION,
     tags = STYLE)
+@SuppressWarnings("java:S2160" /* Super class equality definition suffices. */)
 public final class LexicographicalAnnotationAttributeListing extends BugChecker
     implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
@@ -74,6 +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
@@ -93,7 +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);
   }
 
@@ -216,7 +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.
@@ -46,9 +46,20 @@ 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.
+   */
+  @SuppressWarnings({
+    "java:S1067",
+    "java:S3358"
+  } /* Avoiding the nested ternary operator hurts readability. */)
   private static final Comparator<@Nullable AnnotationType> BY_ANNOTATION_TYPE =
       (a, b) ->
-          (a == null || a == DECLARATION) && b == TYPE ? -1 : a == TYPE && b == DECLARATION ? 1 : 0;
+          (a == null || a == DECLARATION) && b == TYPE
+              ? -1
+              : (a == TYPE && b == DECLARATION ? 1 : 0);
 
   /** Instantiates a new {@link LexicographicalAnnotationListing} instance. */
   public LexicographicalAnnotationListing() {}

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

@@ -0,0 +1,86 @@
+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.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.argument;
+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.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.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.ExpressionTree;
+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.utils.MoreASTHelpers;
+
+/**
+ * A {@link BugChecker} that flags the use of {@link org.mockito.Mockito#mock(Class)} and {@link
+ * org.mockito.Mockito#spy(Class)} where instead the type to be mocked or spied can be derived from
+ * context.
+ */
+// XXX: This check currently does not flag method invocation arguments. When adding support for
+// this, consider that in some cases the type to be mocked or spied must be specified explicitly so
+// as to disambiguate between method overloads.
+// XXX: This check currently does not flag (implicit or explicit) lambda return expressions.
+// XXX: This check currently does not drop suppressions that become obsolete after the
+// suggested fix is applied; consider adding support for this.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Don't unnecessarily pass a type to Mockito's `mock(Class)` and `spy(Class)` methods",
+    link = BUG_PATTERNS_BASE_URL + "MockitoMockClassReference",
+    linkType = CUSTOM,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class MockitoMockClassReference extends BugChecker
+    implements MethodInvocationTreeMatcher {
+  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.getCanonicalName()), not(isVariable()))),
+          staticMethod().onClass("org.mockito.Mockito").namedAnyOf("mock", "spy"));
+
+  /** Instantiates a new {@link MockitoMockClassReference} instance. */
+  public MockitoMockClassReference() {}
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!MOCKITO_MOCK_OR_SPY_WITH_HARDCODED_TYPE.matches(tree, state)
+        || !isTypeDerivableFromContext(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    List<? extends ExpressionTree> arguments = tree.getArguments();
+    return describeMatch(tree, SuggestedFixes.removeElement(arguments.get(0), arguments, state));
+  }
+
+  private static boolean isTypeDerivableFromContext(MethodInvocationTree tree, VisitorState state) {
+    Tree parent = state.getPath().getParentPath().getLeaf();
+    switch (parent.getKind()) {
+      case VARIABLE:
+        return !ASTHelpers.hasImplicitType((VariableTree) parent, state)
+            && MoreASTHelpers.areSameType(tree, parent, state);
+      case ASSIGNMENT:
+        return MoreASTHelpers.areSameType(tree, parent, state);
+      case RETURN:
+        return MoreASTHelpers.findMethodExitedOnReturn(state)
+            .filter(m -> MoreASTHelpers.areSameType(tree, m.getReturnType(), state))
+            .isPresent();
+      default:
+        return false;
+    }
+  }
+}

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
@@ -43,6 +43,7 @@ import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 // emitting a value (e.g. `Mono.empty()`, `someFlux.then()`, ...), or known not to complete normally
 // (`Mono.never()`, `someFlux.repeat()`, `Mono.error(...)`, ...). The latter category could
 // potentially be split out further.
+@SuppressWarnings("java:S1192" /* Factoring out repeated method names impacts readability. */)
 public final class NonEmptyMono extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> MONO_SIZE_CHECK =
@@ -71,7 +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
@@ -49,26 +50,27 @@ import tech.picnic.errorprone.bugpatterns.util.SourceCode;
     linkType = CUSTOM,
     severity = WARNING,
     tags = PERFORMANCE)
+@SuppressWarnings("java:S1192" /* Factoring out repeated method names impacts readability. */)
 public final class PrimitiveComparison extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   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() {}
@@ -166,10 +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

@@ -7,6 +7,7 @@ import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.allOf;
 import static com.google.errorprone.matchers.Matchers.anyMethod;
 import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.anything;
 import static com.google.errorprone.matchers.Matchers.argumentCount;
 import static com.google.errorprone.matchers.Matchers.isNonNullUsingDataflow;
 import static com.google.errorprone.matchers.Matchers.isSameType;
@@ -14,9 +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;
@@ -49,9 +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)
@@ -61,15 +65,18 @@ import tech.picnic.errorprone.bugpatterns.util.SourceCode;
     linkType = CUSTOM,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
+@SuppressWarnings({
+  "java:S1192" /* Factoring out repeated method names impacts readability. */,
+  "java:S2160" /* Super class equality definition suffices. */,
+  "key-to-resolve-AnnotationUseStyle-and-TrailingComment-check-conflict"
+})
 public final class RedundantStringConversion extends BugChecker
     implements BinaryTreeMatcher, CompoundAssignmentTreeMatcher, MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String EXTRA_STRING_CONVERSION_METHODS_FLAG =
       "RedundantStringConversion:ExtraConversionMethods";
 
-  @SuppressWarnings("UnnecessaryLambda")
-  private static final Matcher<ExpressionTree> ANY_EXPR = (t, s) -> true;
-
+  private static final Matcher<ExpressionTree> ANY_EXPR = anything();
   private static final Matcher<ExpressionTree> LOCALE = isSameType(Locale.class);
   private static final Matcher<ExpressionTree> MARKER = isSubtypeOf("org.slf4j.Marker");
   private static final Matcher<ExpressionTree> STRING = isSameType(String.class);
@@ -81,7 +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(
@@ -95,7 +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()
@@ -104,35 +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()
@@ -151,7 +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);
   }
 
@@ -164,7 +174,7 @@ public final class RedundantStringConversion extends BugChecker
     ExpressionTree lhs = tree.getLeftOperand();
     ExpressionTree rhs = tree.getRightOperand();
     if (!STRING.matches(lhs, state)) {
-      return finalize(tree, tryFix(rhs, state, STRING));
+      return createDescription(tree, tryFix(rhs, state, STRING));
     }
 
     List<SuggestedFix.Builder> fixes = new ArrayList<>();
@@ -178,7 +188,7 @@ public final class RedundantStringConversion extends BugChecker
     }
     tryFix(rhs, state, ANY_EXPR).ifPresent(fixes::add);
 
-    return finalize(tree, fixes.stream().reduce(SuggestedFix.Builder::merge));
+    return createDescription(tree, fixes.stream().reduce(SuggestedFix.Builder::merge));
   }
 
   @Override
@@ -187,36 +197,36 @@ public final class RedundantStringConversion extends BugChecker
       return Description.NO_MATCH;
     }
 
-    return finalize(tree, tryFix(tree.getExpression(), state, ANY_EXPR));
+    return createDescription(tree, tryFix(tree.getExpression(), state, ANY_EXPR));
   }
 
   @Override
   public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
     if (STRINGBUILDER_APPEND_INVOCATION.matches(tree, state)) {
-      return finalize(tree, tryFixPositionalConverter(tree.getArguments(), state, 0));
+      return createDescription(tree, tryFixPositionalConverter(tree.getArguments(), state, 0));
     }
 
     if (STRINGBUILDER_INSERT_INVOCATION.matches(tree, state)) {
-      return finalize(tree, tryFixPositionalConverter(tree.getArguments(), state, 1));
+      return createDescription(tree, tryFixPositionalConverter(tree.getArguments(), state, 1));
     }
 
     if (FORMATTER_INVOCATION.matches(tree, state)) {
-      return finalize(tree, tryFixFormatter(tree.getArguments(), state));
+      return createDescription(tree, tryFixFormatter(tree.getArguments(), state));
     }
 
     if (GUAVA_GUARD_INVOCATION.matches(tree, state)) {
-      return finalize(tree, tryFixGuavaGuard(tree.getArguments(), state));
+      return createDescription(tree, tryFixGuavaGuard(tree.getArguments(), state));
     }
 
     if (SLF4J_LOGGER_INVOCATION.matches(tree, state)) {
-      return finalize(tree, tryFixSlf4jLogger(tree.getArguments(), state));
+      return createDescription(tree, tryFixSlf4jLogger(tree.getArguments(), state));
     }
 
     if (instanceMethod().matches(tree, state)) {
-      return finalize(tree, tryFix(tree, state, STRING));
+      return createDescription(tree, tryFix(tree, state, STRING));
     }
 
-    return finalize(tree, tryFix(tree, state, NON_NULL_STRING));
+    return createDescription(tree, tryFix(tree, state, NON_NULL_STRING));
   }
 
   private Optional<SuggestedFix.Builder> tryFixPositionalConverter(
@@ -299,7 +309,7 @@ public final class RedundantStringConversion extends BugChecker
 
     /* Simplify the values to be plugged into the format pattern, if possible. */
     return arguments.stream()
-        .skip(patternIndex + 1)
+        .skip(patternIndex + 1L)
         .map(arg -> tryFix(arg, state, remainingArgFilter))
         .flatMap(Optional::stream)
         .reduce(SuggestedFix.Builder::merge);
@@ -363,7 +373,7 @@ public final class RedundantStringConversion extends BugChecker
     return Optional.of(Iterables.getOnlyElement(methodInvocation.getArguments()));
   }
 
-  private Description finalize(Tree tree, Optional<SuggestedFix.Builder> fixes) {
+  private Description createDescription(Tree tree, Optional<SuggestedFix.Builder> fixes) {
     return fixes
         .map(SuggestedFix.Builder::build)
         .map(fix -> describeMatch(tree, fix))

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
@@ -69,14 +73,20 @@ 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"),
                   isSameType("javax.servlet.http.HttpServletResponse"),
                   isSameType("org.springframework.http.HttpMethod"),
+                  isSameType("org.springframework.ui.Model"),
+                  isSameType("org.springframework.validation.BindingResult"),
                   isSameType("org.springframework.web.context.request.NativeWebRequest"),
                   isSameType("org.springframework.web.context.request.WebRequest"),
                   isSameType("org.springframework.web.server.ServerWebExchange"),
@@ -95,8 +105,9 @@ public final class RequestMappingAnnotation extends BugChecker implements Method
             && LACKS_PARAMETER_ANNOTATION.matches(tree, state)
         ? buildDescription(tree)
             .setMessage(
-                "Not all parameters of this request mapping method are annotated; this may be a mistake. "
-                    + "If the unannotated parameters represent query string parameters, annotate them with `@RequestParam`.")
+                "Not all parameters of this request mapping method are annotated; this may be a "
+                    + "mistake. If the unannotated parameters represent query string parameters, "
+                    + "annotate them with `@RequestParam`.")
             .build()
         : Description.NO_MATCH;
   }

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)
@@ -38,6 +39,7 @@ import tech.picnic.errorprone.bugpatterns.util.Flags;
     linkType = CUSTOM,
     severity = ERROR,
     tags = LIKELY_ERROR)
+@SuppressWarnings("java:S2160" /* Super class equality definition suffices. */)
 public final class RequestParamType extends BugChecker implements VariableTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String SUPPORTED_CUSTOM_TYPES_FLAG = "RequestParamType:SupportedCustomTypes";
@@ -54,7 +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/bugpatterns/util/SourceCode.java

@@ -1,62 +0,0 @@
-package tech.picnic.errorprone.bugpatterns.util;
-
-import static com.sun.tools.javac.util.Position.NOPOS;
-
-import com.google.common.base.CharMatcher;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.fixes.SuggestedFix;
-import com.sun.source.tree.Tree;
-import com.sun.tools.javac.util.JCDiagnostic.DiagnosticPosition;
-
-/**
- * A collection of Error Prone utility methods for dealing with the source code representation of
- * AST nodes.
- */
-public final class SourceCode {
-  /** The complement of {@link CharMatcher#whitespace()}. */
-  private static final CharMatcher NON_WHITESPACE_MATCHER = CharMatcher.whitespace().negate();
-
-  private SourceCode() {}
-
-  /**
-   * Returns a string representation of the given {@link Tree}, preferring the original source code
-   * (if available) over its prettified representation.
-   *
-   * @param tree The AST node of interest.
-   * @param state A {@link VisitorState} describing the context in which the given {@link Tree} is
-   *     found.
-   * @return A non-{@code null} string.
-   */
-  public static String treeToString(Tree tree, VisitorState state) {
-    String src = state.getSourceForNode(tree);
-    return src != null ? src : tree.toString();
-  }
-
-  /**
-   * Creates a {@link SuggestedFix} for the deletion of the given {@link Tree}, including any
-   * whitespace that follows it.
-   *
-   * <p>Removing trailing whitespace may prevent the introduction of an empty line at the start of a
-   * code block; such empty lines are not removed when formatting the code using Google Java Format.
-   *
-   * @param tree The AST node of interest.
-   * @param state A {@link VisitorState} describing the context in which the given {@link Tree} is
-   *     found.
-   * @return A non-{@code null} {@link SuggestedFix} similar to one produced by {@link
-   *     SuggestedFix#delete(Tree)}.
-   */
-  public static SuggestedFix deleteWithTrailingWhitespace(Tree tree, VisitorState state) {
-    CharSequence sourceCode = state.getSourceCode();
-    int endPos = state.getEndPosition(tree);
-    if (sourceCode == null || endPos == NOPOS) {
-      /* We can't identify the trailing whitespace; delete just the tree. */
-      return SuggestedFix.delete(tree);
-    }
-
-    int whitespaceEndPos = NON_WHITESPACE_MATCHER.indexIn(sourceCode, endPos);
-    return SuggestedFix.replace(
-        ((DiagnosticPosition) tree).getStartPosition(),
-        whitespaceEndPos == -1 ? sourceCode.length() : whitespaceEndPos,
-        "");
-  }
-}

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

@@ -3,77 +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.HashMap;
-import java.util.HashSet;
-import java.util.LinkedHashMap;
-import java.util.LinkedHashSet;
+import java.util.Collection;
 import java.util.Map;
-import java.util.TreeMap;
-import java.util.TreeSet;
+import java.util.Set;
 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());
@@ -109,15 +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
@@ -145,12 +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);
     }
   }
@@ -184,12 +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);
     }
   }
@@ -220,6 +179,20 @@ final class AssertJMapRules {
     }
   }
 
+  static final class AssertThatMapContainsOnlyKeys<K, V> {
+    @BeforeTemplate
+    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<? extends K> keys) {
+      return assertThat(map).containsOnlyKeys(keys);
+    }
+  }
+
   static final class AssertThatMapContainsValue<K, V> {
     @BeforeTemplate
     AbstractBooleanAssert<?> before(Map<K, V> map, V value) {

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

@@ -23,6 +23,8 @@ final class AssertJPrimitiveRules {
     }
 
     @BeforeTemplate
+    @SuppressWarnings(
+        "java:S1244" /* The (in)equality checks are fragile, but may be seen in the wild. */)
     AbstractBooleanAssert<?> before(double actual, double expected) {
       return Refaster.anyOf(
           assertThat(actual == expected).isTrue(), assertThat(actual != expected).isFalse());
@@ -43,6 +45,8 @@ final class AssertJPrimitiveRules {
     }
 
     @BeforeTemplate
+    @SuppressWarnings(
+        "java:S1244" /* The (in)equality checks are fragile, but may be seen in the wild. */)
     AbstractBooleanAssert<?> before(double actual, double expected) {
       return Refaster.anyOf(
           assertThat(actual != expected).isTrue(), assertThat(actual == expected).isFalse());

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));
     }
 
@@ -2024,8 +1973,8 @@ final class AssertJRules {
   ////////////////////////////////////////////////////////////////////////////
   // Above: Generated code.
 
-  ///////////////////////////////////////////////////////////////////////////////////////////////////////
-  ///////////////////////////////////////////////////////////////////////////////////////////////////////
+  ////////////////////////////////////////////////////////////////////////////
+  ////////////////////////////////////////////////////////////////////////////
   // Organize the code below.
 
   // XXX: Do the "single Comparable" match shown below.

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

@@ -1,11 +1,16 @@
 package tech.picnic.errorprone.refasterrules;
 
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import java.io.IOException;
+import java.nio.charset.Charset;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import org.assertj.core.api.AbstractAssert;
 import org.assertj.core.api.AbstractStringAssert;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
@@ -89,4 +94,30 @@ final class AssertJStringRules {
       return assertThat(string).doesNotMatch(regex);
     }
   }
+
+  static final class AssertThatPathContent {
+    @BeforeTemplate
+    AbstractStringAssert<?> before(Path path, Charset charset) throws IOException {
+      return assertThat(Files.readString(path, charset));
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractStringAssert<?> after(Path path, Charset charset) {
+      return assertThat(path).content(charset);
+    }
+  }
+
+  static final class AssertThatPathContentUtf8 {
+    @BeforeTemplate
+    AbstractStringAssert<?> before(Path path) throws IOException {
+      return assertThat(Files.readString(path));
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractStringAssert<?> after(Path path) {
+      return assertThat(path).content(UTF_8);
+    }
+  }
 }

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

@@ -47,7 +47,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalArgumentExceptionHasMessage {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalArgumentException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIllegalArgumentException().isThrownBy(throwingCallable).withMessage(message);
     }
@@ -64,7 +64,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalArgumentExceptionHasMessageParameters {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalArgumentException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
       return assertThatIllegalArgumentException()
@@ -85,7 +85,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalArgumentExceptionHasMessageStartingWith {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalArgumentException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIllegalArgumentException()
           .isThrownBy(throwingCallable)
@@ -104,7 +104,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalArgumentExceptionHasMessageContaining {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalArgumentException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIllegalArgumentException()
           .isThrownBy(throwingCallable)
@@ -123,7 +123,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalArgumentExceptionHasMessageNotContainingAny {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalArgumentException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable, @Repeated CharSequence values) {
       return assertThatIllegalArgumentException()
@@ -157,7 +157,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalStateExceptionHasMessage {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalStateException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIllegalStateException().isThrownBy(throwingCallable).withMessage(message);
     }
@@ -174,7 +174,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalStateExceptionHasMessageParameters {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalStateException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
       return assertThatIllegalStateException()
@@ -195,7 +195,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalStateExceptionHasMessageStartingWith {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalStateException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIllegalStateException()
           .isThrownBy(throwingCallable)
@@ -214,7 +214,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalStateExceptionHasMessageContaining {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalStateException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIllegalStateException()
           .isThrownBy(throwingCallable)
@@ -233,7 +233,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByIllegalStateExceptionHasMessageNotContaining {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByIllegalStateException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIllegalStateException()
           .isThrownBy(throwingCallable)
@@ -265,7 +265,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByNullPointerExceptionHasMessage {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByNullPointerException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByNullPointerException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatNullPointerException().isThrownBy(throwingCallable).withMessage(message);
     }
@@ -282,7 +282,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByNullPointerExceptionHasMessageParameters {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByNullPointerException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByNullPointerException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
       return assertThatNullPointerException()
@@ -303,7 +303,7 @@ final class AssertJThrowingCallableRules {
   static final class AssertThatThrownByNullPointerExceptionHasMessageStartingWith {
     @BeforeTemplate
     @SuppressWarnings(
-        "AssertThatThrownByNullPointerException" /* Matches strictly more specific expressions. */)
+        "AssertThatThrownByNullPointerException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatNullPointerException()
           .isThrownBy(throwingCallable)
@@ -319,6 +319,44 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByNullPointerExceptionHasMessageContaining {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByNullPointerException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatNullPointerException()
+          .isThrownBy(throwingCallable)
+          .withMessageContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(NullPointerException.class)
+          .hasMessageContaining(message);
+    }
+  }
+
+  static final class AssertThatThrownByNullPointerExceptionHasMessageNotContaining {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByNullPointerException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatNullPointerException()
+          .isThrownBy(throwingCallable)
+          .withMessageNotContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(NullPointerException.class)
+          .hasMessageNotContaining(message);
+    }
+  }
+
   static final class AssertThatThrownByIOException {
     @BeforeTemplate
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable) {
@@ -334,8 +372,7 @@ final class AssertJThrowingCallableRules {
 
   static final class AssertThatThrownByIOExceptionHasMessage {
     @BeforeTemplate
-    @SuppressWarnings(
-        "AssertThatThrownByIOException" /* Matches strictly more specific expressions. */)
+    @SuppressWarnings("AssertThatThrownByIOException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIOException().isThrownBy(throwingCallable).withMessage(message);
     }
@@ -351,8 +388,7 @@ final class AssertJThrowingCallableRules {
 
   static final class AssertThatThrownByIOExceptionHasMessageParameters {
     @BeforeTemplate
-    @SuppressWarnings(
-        "AssertThatThrownByIOException" /* Matches strictly more specific expressions. */)
+    @SuppressWarnings("AssertThatThrownByIOException" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
       return assertThatIOException().isThrownBy(throwingCallable).withMessage(message, parameters);
@@ -368,27 +404,75 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByIOExceptionHasMessageStartingWith {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownByIOException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIOException().isThrownBy(throwingCallable).withMessageStartingWith(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IOException.class)
+          .hasMessageStartingWith(message);
+    }
+  }
+
+  static final class AssertThatThrownByIOExceptionHasMessageContaining {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownByIOException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIOException().isThrownBy(throwingCallable).withMessageContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IOException.class)
+          .hasMessageContaining(message);
+    }
+  }
+
+  static final class AssertThatThrownByIOExceptionHasMessageNotContaining {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownByIOException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIOException().isThrownBy(throwingCallable).withMessageNotContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IOException.class)
+          .hasMessageNotContaining(message);
+    }
+  }
+
   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);
     }
   }
 
   static final class AssertThatThrownByHasMessage {
     @BeforeTemplate
-    @SuppressWarnings("AssertThatThrownBy" /* Matches strictly more specific expressions. */)
+    @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)
@@ -398,8 +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);
     }
@@ -407,10 +491,10 @@ final class AssertJThrowingCallableRules {
 
   static final class AssertThatThrownByHasMessageParameters {
     @BeforeTemplate
-    @SuppressWarnings("AssertThatThrownBy" /* Matches strictly more specific expressions. */)
+    @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)
@@ -421,8 +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)
@@ -431,6 +515,78 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByHasMessageStartingWith {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatExceptionOfType(exceptionType)
+          .isThrownBy(throwingCallable)
+          .withMessageStartingWith(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(exceptionType)
+          .hasMessageStartingWith(message);
+    }
+  }
+
+  static final class AssertThatThrownByHasMessageContaining {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatExceptionOfType(exceptionType)
+          .isThrownBy(throwingCallable)
+          .withMessageContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(exceptionType)
+          .hasMessageContaining(message);
+    }
+  }
+
+  static final class AssertThatThrownByHasMessageNotContaining {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatExceptionOfType(exceptionType)
+          .isThrownBy(throwingCallable)
+          .withMessageNotContaining(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(exceptionType)
+          .hasMessageNotContaining(message);
+    }
+  }
+
   // XXX: Drop this rule in favour of a generic Error Prone check that flags `String.format(...)`
   // arguments to a wide range of format methods.
   static final class AbstractThrowableAssertHasMessage {

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);
     }
   }
@@ -115,6 +114,7 @@ final class AssortedRules {
   // intelligently.
   static final class LogicalImplication {
     @BeforeTemplate
+    @SuppressWarnings("java:S2589" /* This violation will be rewritten. */)
     boolean before(boolean firstTest, boolean secondTest) {
       return firstTest || (!firstTest && secondTest);
     }

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;
@@ -56,6 +57,7 @@ final class BigDecimalRules {
   // `BugChecker`.
   static final class BigDecimalValueOf {
     @BeforeTemplate
+    @SuppressWarnings("java:S2111" /* This violation will be rewritten. */)
     BigDecimal before(double value) {
       return new BigDecimal(value);
     }
@@ -65,4 +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

@@ -0,0 +1,70 @@
+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. */
+@OnlineDocumentation
+final class BugCheckerRules {
+  private BugCheckerRules() {}
+
+  /**
+   * Avoid calling {@link BugCheckerRefactoringTestHelper#setFixChooser(FixChooser)} or {@link
+   * BugCheckerRefactoringTestHelper#setImportOrder(String)} with their respective default values.
+   */
+  static final class BugCheckerRefactoringTestHelperIdentity {
+    @BeforeTemplate
+    BugCheckerRefactoringTestHelper before(BugCheckerRefactoringTestHelper helper) {
+      return Refaster.anyOf(
+          helper.setFixChooser(FixChoosers.FIRST), helper.setImportOrder("static-first"));
+    }
+
+    @AfterTemplate
+    @CanIgnoreReturnValue
+    BugCheckerRefactoringTestHelper after(BugCheckerRefactoringTestHelper helper) {
+      return helper;
+    }
+  }
+
+  /**
+   * Prefer {@link BugCheckerRefactoringTestHelper.ExpectOutput#expectUnchanged()} over repeating
+   * the input.
+   */
+  // XXX: This rule assumes that the full source code is specified as a single string, e.g. using a
+  // text block. Support for multi-line source code input would require a `BugChecker`
+  // implementation instead.
+  static final class BugCheckerRefactoringTestHelperAddInputLinesExpectUnchanged {
+    @BeforeTemplate
+    BugCheckerRefactoringTestHelper before(
+        BugCheckerRefactoringTestHelper helper, String path, String source) {
+      return helper.addInputLines(path, source).addOutputLines(path, source);
+    }
+
+    @AfterTemplate
+    BugCheckerRefactoringTestHelper after(
+        BugCheckerRefactoringTestHelper helper, String path, String source) {
+      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

@@ -35,6 +35,7 @@ final class CollectionRules {
    */
   static final class CollectionIsEmpty<T> {
     @BeforeTemplate
+    @SuppressWarnings("java:S1155" /* This violation will be rewritten. */)
     boolean before(Collection<T> collection) {
       return Refaster.anyOf(
           collection.size() == 0,
@@ -73,6 +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}.
@@ -163,6 +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();
     }
@@ -233,6 +241,7 @@ final class ComparatorRules {
   /** Prefer {@link Comparators#min(Comparable, Comparable)}} over more verbose alternatives. */
   static final class MinOfPairNaturalOrder<T extends Comparable<? super T>> {
     @BeforeTemplate
+    @SuppressWarnings("java:S1067" /* The conditional operators are independent. */)
     T before(T value1, T value2) {
       return Refaster.anyOf(
           value1.compareTo(value2) <= 0 ? value1 : value2,
@@ -259,6 +268,7 @@ final class ComparatorRules {
    */
   static final class MinOfPairCustomOrder<T> {
     @BeforeTemplate
+    @SuppressWarnings("java:S1067" /* The conditional operators are independent. */)
     T before(T value1, T value2, Comparator<T> cmp) {
       return Refaster.anyOf(
           cmp.compare(value1, value2) <= 0 ? value1 : value2,
@@ -285,7 +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();
     }
@@ -299,6 +308,7 @@ final class ComparatorRules {
   /** Prefer {@link Comparators#max(Comparable, Comparable)}} over more verbose alternatives. */
   static final class MaxOfPairNaturalOrder<T extends Comparable<? super T>> {
     @BeforeTemplate
+    @SuppressWarnings("java:S1067" /* The conditional operators are independent. */)
     T before(T value1, T value2) {
       return Refaster.anyOf(
           value1.compareTo(value2) >= 0 ? value1 : value2,
@@ -325,6 +335,7 @@ final class ComparatorRules {
    */
   static final class MaxOfPairCustomOrder<T> {
     @BeforeTemplate
+    @SuppressWarnings("java:S1067" /* The conditional operators are independent. */)
     T before(T value1, T value2, Comparator<T> cmp) {
       return Refaster.anyOf(
           cmp.compare(value1, value2) >= 0 ? value1 : value2,
@@ -376,4 +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;
     }
@@ -237,6 +239,7 @@ final class DoubleStreamRules {
   /** Prefer {@link DoubleStream#anyMatch(DoublePredicate)} over more contrived alternatives. */
   static final class DoubleStreamAnyMatch {
     @BeforeTemplate
+    @SuppressWarnings("java:S4034" /* This violation will be rewritten. */)
     boolean before(DoubleStream stream, DoublePredicate predicate) {
       return Refaster.anyOf(
           !stream.noneMatch(predicate), stream.filter(predicate).findAny().isPresent());
@@ -274,4 +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;
 
@@ -30,6 +36,7 @@ final class EqualityRules {
 
     @AfterTemplate
     @AlsoNegation
+    @SuppressWarnings("java:S1698" /* Reference comparison is valid for enums. */)
     boolean after(T a, T b) {
       return a == b;
     }
@@ -56,11 +63,13 @@ final class EqualityRules {
   /** Avoid double negations; this is not Javascript. */
   static final class DoubleNegation {
     @BeforeTemplate
+    @SuppressWarnings("java:S2761" /* This violation will be rewritten. */)
     boolean before(boolean b) {
       return !!b;
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     boolean after(boolean b) {
       return b;
     }
@@ -72,6 +81,7 @@ final class EqualityRules {
    */
   // XXX: Replacing `a ? !b : b` with `a != b` changes semantics if both `a` and `b` are boxed
   // booleans.
+  @SuppressWarnings("java:S1940" /* This violation will be rewritten. */)
   static final class Negation {
     @BeforeTemplate
     boolean before(boolean a, boolean b) {
@@ -79,6 +89,8 @@ final class EqualityRules {
     }
 
     @BeforeTemplate
+    @SuppressWarnings(
+        "java:S1244" /* The equality check is fragile, but may be seen in the wild. */)
     boolean before(double a, double b) {
       return !(a == b);
     }
@@ -100,6 +112,7 @@ final class EqualityRules {
    */
   // XXX: Replacing `a ? b : !b` with `a == b` changes semantics if both `a` and `b` are boxed
   // booleans.
+  @SuppressWarnings("java:S1940" /* This violation will be rewritten. */)
   static final class IndirectDoubleNegation {
     @BeforeTemplate
     boolean before(boolean a, boolean b) {
@@ -107,6 +120,8 @@ final class EqualityRules {
     }
 
     @BeforeTemplate
+    @SuppressWarnings(
+        "java:S1244" /* The inequality check is fragile, but may be seen in the wild. */)
     boolean before(double a, double b) {
       return !(a != b);
     }
@@ -121,4 +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

@@ -4,14 +4,15 @@ 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;
 import com.google.common.collect.Maps;
 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;
@@ -22,6 +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
@@ -62,27 +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
@@ -126,8 +130,8 @@ final class ImmutableMapRules {
   }
 
   /**
-   * Don't map a a stream's elements to map entries, only to subsequently collect them into an
-   * {@link ImmutableMap}. The collection can be performed directly.
+   * Don't map a stream's elements to map entries, only to subsequently collect them into an {@link
+   * ImmutableMap}. The collection can be performed directly.
    */
   abstract static class StreamOfMapEntriesToImmutableMap<E, K, V> {
     @Placeholder(allowsIdentity = true)
@@ -156,25 +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
@@ -249,7 +257,8 @@ final class ImmutableMapRules {
    * Prefer {@link ImmutableMap#of(Object, Object, Object, Object)} over alternatives that don't
    * communicate the immutability of the resulting map at the type level.
    */
-  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  // XXX: Consider introducing a `BugChecker` to replace these `ImmutableMapOfX` rules. That will
+  // also make it easier to rewrite various `ImmutableMap.builder()` variants.
   static final class ImmutableMapOf2<K, V> {
     @BeforeTemplate
     Map<K, V> before(K k1, V v1, K k2, V v2) {
@@ -266,7 +275,8 @@ final class ImmutableMapRules {
    * Prefer {@link ImmutableMap#of(Object, Object, Object, Object, Object, Object)} over
    * alternatives that don't communicate the immutability of the resulting map at the type level.
    */
-  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  // XXX: Consider introducing a `BugChecker` to replace these `ImmutableMapOfX` rules. That will
+  // also make it easier to rewrite various `ImmutableMap.builder()` variants.
   static final class ImmutableMapOf3<K, V> {
     @BeforeTemplate
     Map<K, V> before(K k1, V v1, K k2, V v2, K k3, V v3) {
@@ -284,7 +294,9 @@ final class ImmutableMapRules {
    * over alternatives that don't communicate the immutability of the resulting map at the type
    * level.
    */
-  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  // XXX: Consider introducing a `BugChecker` to replace these `ImmutableMapOfX` rules. That will
+  // also make it easier to rewrite various `ImmutableMap.builder()` variants.
+  @SuppressWarnings("java:S107" /* Can't avoid many method parameters here. */)
   static final class ImmutableMapOf4<K, V> {
     @BeforeTemplate
     Map<K, V> before(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4) {
@@ -302,7 +314,9 @@ final class ImmutableMapRules {
    * Object, Object)} over alternatives that don't communicate the immutability of the resulting map
    * at the type level.
    */
-  // XXX: Also rewrite the `ImmutableMap.builder()` variant?
+  // XXX: Consider introducing a `BugChecker` to replace these `ImmutableMapOfX` rules. That will
+  // also make it easier to rewrite various `ImmutableMap.builder()` variants.
+  @SuppressWarnings("java:S107" /* Can't avoid many method parameters here. */)
   static final class ImmutableMapOf5<K, V> {
     @BeforeTemplate
     Map<K, V> before(K k1, V v1, K k2, V v2, K k3, V v3, K k4, V v4, K k5, V v5) {
@@ -315,6 +329,48 @@ final class ImmutableMapRules {
     }
   }
 
+  /**
+   * Prefer creation of an immutable submap using {@link Maps#filterKeys(Map, Predicate)} over more
+   * contrived alternatives.
+   */
+  abstract static class ImmutableMapCopyOfMapsFilterKeys<K, V> {
+    @Placeholder(allowsIdentity = true)
+    abstract boolean keyFilter(@MayOptionallyUse K key);
+
+    @BeforeTemplate
+    ImmutableMap<K, V> before(ImmutableMap<K, V> map) {
+      return map.entrySet().stream()
+          .filter(e -> keyFilter(e.getKey()))
+          .collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue));
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(ImmutableMap<K, V> map) {
+      return ImmutableMap.copyOf(Maps.filterKeys(map, k -> keyFilter(k)));
+    }
+  }
+
+  /**
+   * Prefer creation of an immutable submap using {@link Maps#filterValues(Map, Predicate)} over
+   * more contrived alternatives.
+   */
+  abstract static class ImmutableMapCopyOfMapsFilterValues<K, V> {
+    @Placeholder(allowsIdentity = true)
+    abstract boolean valueFilter(@MayOptionallyUse V value);
+
+    @BeforeTemplate
+    ImmutableMap<K, V> before(ImmutableMap<K, V> map) {
+      return map.entrySet().stream()
+          .filter(e -> valueFilter(e.getValue()))
+          .collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue));
+    }
+
+    @AfterTemplate
+    ImmutableMap<K, V> after(ImmutableMap<K, V> map) {
+      return ImmutableMap.copyOf(Maps.filterValues(map, v -> valueFilter(v)));
+    }
+  }
+
   // XXX: Add a rule for this:
   // Maps.transformValues(streamOfEntries.collect(groupBy(fun)), ImmutableMap::copyOf)
   // ->
@@ -323,9 +379,4 @@ final class ImmutableMapRules {
   // map.entrySet().stream().filter(keyPred).forEach(mapBuilder::put)
   // ->
   // mapBuilder.putAll(Maps.filterKeys(map, pred))
-  //
-  // map.entrySet().stream().filter(entry ->
-  // pred(entry.getKey())).collect(toImmutableMap(Map.Entry::getKey, Map.Entry::getValue))
-  // ->
-  // ImmutableMap.copyOf(Maps.filterKeys(map, pred))
 }

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

@@ -4,8 +4,11 @@ import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Collections.emptySet;
 import static java.util.Collections.singleton;
+import static java.util.function.Predicate.not;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Multimap;
+import com.google.common.collect.Sets;
 import com.google.common.collect.Sets.SetView;
 import com.google.common.collect.Streams;
 import com.google.errorprone.refaster.Refaster;
@@ -15,6 +18,7 @@ import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
+import java.util.Map;
 import java.util.Set;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
@@ -211,4 +215,116 @@ final class ImmutableSetRules {
       return ImmutableSet.of(e1, e2, e3, e4, e5);
     }
   }
+
+  /**
+   * Prefer an immutable copy of {@link Sets#difference(Set, Set)} over more contrived alternatives.
+   */
+  static final class SetsDifference<S, T> {
+    @BeforeTemplate
+    ImmutableSet<S> before(Set<S> set1, Set<T> set2) {
+      return set1.stream()
+          .filter(Refaster.anyOf(not(set2::contains), e -> !set2.contains(e)))
+          .collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<S> after(Set<S> set1, Set<T> set2) {
+      return Sets.difference(set1, set2).immutableCopy();
+    }
+  }
+
+  /**
+   * Prefer an immutable copy of {@link Sets#difference(Set, Set)} over more contrived alternatives.
+   */
+  static final class SetsDifferenceMap<T, K, V> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Set<T> set, Map<K, V> map) {
+      return set.stream()
+          .filter(Refaster.anyOf(not(map::containsKey), e -> !map.containsKey(e)))
+          .collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<K> after(Set<K> set, Map<K, V> map) {
+      return Sets.difference(set, map.keySet()).immutableCopy();
+    }
+  }
+
+  /**
+   * Prefer an immutable copy of {@link Sets#difference(Set, Set)} over more contrived alternatives.
+   */
+  static final class SetsDifferenceMultimap<T, K, V> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Set<T> set, Multimap<K, V> multimap) {
+      return set.stream()
+          .filter(Refaster.anyOf(not(multimap::containsKey), e -> !multimap.containsKey(e)))
+          .collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(Set<T> set, Multimap<K, V> multimap) {
+      return Sets.difference(set, multimap.keySet()).immutableCopy();
+    }
+  }
+
+  /**
+   * Prefer an immutable copy of {@link Sets#intersection(Set, Set)} over more contrived
+   * alternatives.
+   */
+  static final class SetsIntersection<S, T> {
+    @BeforeTemplate
+    ImmutableSet<S> before(Set<S> set1, Set<T> set2) {
+      return set1.stream().filter(set2::contains).collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<S> after(Set<S> set1, Set<T> set2) {
+      return Sets.intersection(set1, set2).immutableCopy();
+    }
+  }
+
+  /**
+   * Prefer an immutable copy of {@link Sets#intersection(Set, Set)} over more contrived
+   * alternatives.
+   */
+  static final class SetsIntersectionMap<T, K, V> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Set<T> set, Map<K, V> map) {
+      return set.stream().filter(map::containsKey).collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(Set<T> set, Map<K, V> map) {
+      return Sets.intersection(set, map.keySet()).immutableCopy();
+    }
+  }
+
+  /**
+   * Prefer an immutable copy of {@link Sets#intersection(Set, Set)} over more contrived
+   * alternatives.
+   */
+  static final class SetsIntersectionMultimap<T, K, V> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Set<T> set, Multimap<K, V> multimap) {
+      return set.stream().filter(multimap::containsKey).collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(Set<T> set, Multimap<K, V> multimap) {
+      return Sets.intersection(set, multimap.keySet()).immutableCopy();
+    }
+  }
+
+  /** Prefer an immutable copy of {@link Sets#union(Set, Set)} over more contrived alternatives. */
+  static final class SetsUnion<S, T extends S, U extends S> {
+    @BeforeTemplate
+    ImmutableSet<S> before(Set<T> set1, Set<U> set2) {
+      return Stream.concat(set1.stream(), set2.stream()).collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    ImmutableSet<S> after(Set<T> set1, Set<U> set2) {
+      return Sets.union(set1, set2).immutableCopy();
+    }
+  }
 }

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;
     }
@@ -250,6 +252,7 @@ final class IntStreamRules {
   /** Prefer {@link IntStream#anyMatch(IntPredicate)} over more contrived alternatives. */
   static final class IntStreamAnyMatch {
     @BeforeTemplate
+    @SuppressWarnings("java:S4034" /* This violation will be rewritten. */)
     boolean before(IntStream stream, IntPredicate predicate) {
       return Refaster.anyOf(
           !stream.noneMatch(predicate), stream.filter(predicate).findAny().isPresent());
@@ -287,4 +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;
@@ -34,8 +33,7 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
  * <p>Note that, while both libraries throw an {@link AssertionError} in case of an assertion
  * failure, the exact subtype used generally differs.
  */
-// XXX: Not all `org.assertj.core.api.Assertions` methods have an associated Refaster rule yet;
-// expand this class.
+// XXX: Not all JUnit `Assertions` methods have an associated Refaster rule yet; expand this class.
 // XXX: Introduce a `@Matcher` on `Executable` and `ThrowingSupplier` expressions, such that they
 // are only matched if they are also compatible with the `ThrowingCallable` functional interface.
 // When implementing such a matcher, note that expressions with a non-void return type such as
@@ -45,21 +43,6 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 final class JUnitToAssertJRules {
   private JUnitToAssertJRules() {}
 
-  public ImmutableSet<?> 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() {
@@ -79,8 +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);
     }
@@ -92,8 +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);
     }
@@ -283,26 +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);
     }
   }
@@ -322,26 +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);
     }
   }
@@ -362,13 +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);
     }
   }
@@ -376,13 +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);
     }
   }
@@ -402,26 +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);
     }
   }
@@ -495,26 +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;
     }
@@ -250,6 +252,7 @@ final class LongStreamRules {
   /** Prefer {@link LongStream#anyMatch(LongPredicate)} over more contrived alternatives. */
   static final class LongStreamAnyMatch {
     @BeforeTemplate
+    @SuppressWarnings("java:S4034" /* This violation will be rewritten. */)
     boolean before(LongStream stream, LongPredicate predicate) {
       return Refaster.anyOf(
           !stream.noneMatch(predicate), stream.filter(predicate).findAny().isPresent());
@@ -287,4 +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();
+    }
+  }
 }