WIP: Introduce Checker Framework

To be determined: move to a separate profile?
2026-03-10 08:11:25 +00:00 · 2023-12-26 16:41:00 +01:00
303 changed files with 11602 additions and 50664 deletions
--- a/.github/ISSUE_TEMPLATE/bug_report.md
+++ b/.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. `17.0.13`).
- Error Prone version (e.g. `2.35.1`).
- Error Prone Support version (e.g. `0.19.0`).
+- 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

--- a/.github/release.yml
+++ b/.github/release.yml
@@ -3,16 +3,16 @@ changelog:
    labels:
      - "ignore-changelog"
  categories:
-    - title: ":warning: Update considerations and deprecations"
-      labels:
-        - "breaking change"
-        - "deprecation"
    - title: ":rocket: New Error Prone checks and Refaster rules"
      labels:
        - "new feature"
    - title: ":sparkles: Improvements"
      labels:
        - "improvement"
+    - title: ":warning: Update considerations and deprecations"
+      labels:
+        - "breaking change"
+        - "deprecation"
    - title: ":bug: Bug fixes"
      labels:
        - "bug"
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -9,55 +9,44 @@ jobs:
  build:
    strategy:
      matrix:
-        os: [ ubuntu-24.04 ]
-        jdk: [ 17.0.13, 21.0.5, 23.0.1 ]
+        os: [ ubuntu-22.04 ]
+        jdk: [ 11.0.20, 17.0.8, 21.0.0 ]
        distribution: [ temurin ]
        experimental: [ false ]
        include:
-          - os: macos-15
-            jdk: 17.0.13
+          - os: macos-12
+            jdk: 17.0.8
            distribution: temurin
            experimental: false
-          - os: windows-2025
-            jdk: 17.0.13
+          - os: windows-2022
+            jdk: 17.0.8
            distribution: temurin
            experimental: false
    runs-on: ${{ matrix.os }}
    continue-on-error: ${{ matrix.experimental }}
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
-        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            api.adoptium.net:443
-            github.com:443
-            github-registry-files.githubusercontent.com:443
-            jitpack.io:443
-            maven.pkg.github.com:443
-            objects.githubusercontent.com:443
-            repo.maven.apache.org:443
      # 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@4f7fb9d9675e899ca81c6161dadbba0189a4ebb1 # v1.18.0
+      - name: Check out code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        with:
+          persist-credentials: false
+      - name: Set up JDK
+        uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
        with:
          java-version: ${{ matrix.jdk }}
-          java-distribution: ${{ matrix.distribution }}
-          maven-version: 3.9.9
+          distribution: ${{ matrix.distribution }}
+          cache: maven
      - name: Display build environment details
        run: mvn --version
      - name: Build project against vanilla Error Prone, compile Javadoc
        run: mvn -T1C install javadoc:jar
      - name: Build project with self-check against Error Prone fork
        run: mvn -T1C clean verify -Perror-prone-fork -Pnon-maven-central -Pself-check -s settings.xml
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      - name: Remove installed project artifacts
-        run: mvn dependency:purge-local-repository -DmanualInclude='${project.groupId}' -DresolutionFuzziness=groupId
+        run: mvn build-helper:remove-project-artifact

 # XXX: Enable Codecov once we "go public".
--- a/.github/workflows/codeql.yml
+++ b/.github/workflows/codeql.yml
@@ -19,34 +19,26 @@ jobs:
    permissions:
      contents: read
      security-events: write
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
+      - name: Check out code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            api.adoptium.net:443
-            api.github.com:443
-            github.com:443
-            objects.githubusercontent.com:443
-            repo.maven.apache.org:443
-            uploads.github.com:443
-      - name: Check out code and set up JDK and Maven
-        uses: s4u/setup-maven-action@4f7fb9d9675e899ca81c6161dadbba0189a4ebb1 # v1.18.0
+          persist-credentials: false
+      - name: Set up JDK
+        uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
        with:
-          java-version: 17.0.13
-          java-distribution: temurin
-          maven-version: 3.9.9
+          java-version: 17.0.8
+          distribution: temurin
+          cache: maven
      - name: Initialize CodeQL
-        uses: github/codeql-action/init@f6091c0113d1dcf9b98e269ee48e8a7e51b7bdd4 # v3.28.5
+        uses: github/codeql-action/init@407ffafae6a767df3e0230c3df91b6443ae8df75 # v2.22.8
        with:
          languages: ${{ matrix.language }}
      - name: Perform minimal build
        if: matrix.language == 'java'
        run: mvn -T1C clean package -DskipTests -Dverification.skip
      - name: Perform CodeQL analysis
-        uses: github/codeql-action/analyze@f6091c0113d1dcf9b98e269ee48e8a7e51b7bdd4 # v3.28.5
+        uses: github/codeql-action/analyze@407ffafae6a767df3e0230c3df91b6443ae8df75 # v2.22.8
        with:
          category: /language:${{ matrix.language }}
--- a/.github/workflows/deploy-website.yml
+++ b/.github/workflows/deploy-website.yml
@@ -9,46 +9,18 @@ concurrency:
  group: ${{ github.workflow }}-${{ github.ref }}
 jobs:
  build:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
-        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            api.adoptium.net:443
-            api.github.com:443
-            bestpractices.coreinfrastructure.org:443
-            blog.picnic.nl:443
-            docs.github.com:443
-            errorprone.info:443
-            github.com:443
-            img.shields.io:443
-            index.rubygems.org:443
-            jitpack.io:443
-            maven.apache.org:443
-            objects.githubusercontent.com:443
-            pitest.org:443
-            repo.maven.apache.org:443
-            rubygems.org:443
-            search.maven.org:443
-            securityscorecards.dev:443
-            sonarcloud.io:443
-            www.baeldung.com:443
-            www.bestpractices.dev:443
-            www.youtube.com:443
-            youtrack.jetbrains.com:443
      - name: Check out code
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
          persist-credentials: false
-      - uses: ruby/setup-ruby@28c4deda893d5a96a6b2d958c5b47fc18d65c9d3 # v1.213.0
+      - uses: ruby/setup-ruby@8575951200e472d5f2d95c625da0c7bec8217c42 # v1.161.0
        with:
          working-directory: ./website
          bundler-cache: true
      - name: Configure Github Pages
-        uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5.0.0
+        uses: actions/configure-pages@1f0c5cde4bc74cd7e1254d0cb4de8d49e9068c7d # v4.0.0
      - name: Generate documentation
        run: ./generate-docs.sh
      - name: Build website with Jekyll
@@ -60,7 +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@56afc609e74202658d3ffba0e8f6dda462b719fa # v3.0.1
+        uses: actions/upload-pages-artifact@0252fc4ba7626f0298f0cf00902a25c6afc77fa8 # v3.0.0
        with:
          path: ./website/_site
  deploy:
@@ -69,18 +41,11 @@ jobs:
    permissions:
      id-token: write
      pages: write
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
    environment:
      name: github-pages
      url: ${{ steps.deployment.outputs.page_url }}
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
-        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            api.github.com:443
      - name: Deploy to GitHub Pages
        id: deployment
-        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4.0.5
+        uses: actions/deploy-pages@7a9bd943aa5e5175aeb8502edcc6c1c02d398e10 # v4.0.2
--- a/.github/workflows/openssf-scorecard.yml
+++ b/.github/workflows/openssf-scorecard.yml
@@ -18,36 +18,19 @@ jobs:
      contents: read
      security-events: write
      id-token: write
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
-        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            api.deps.dev:443
-            api.github.com:443
-            api.osv.dev:443
-            api.scorecard.dev:443
-            api.securityscorecards.dev:443
-            github.com:443
-            index.docker.io:443
-            oss-fuzz-build-logs.storage.googleapis.com:443
-            repo.maven.apache.org:443
-            *.sigstore.dev:443
-            www.bestpractices.dev:443
      - name: Check out code
-        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
          persist-credentials: false
      - name: Run OpenSSF Scorecard analysis
-        uses: ossf/scorecard-action@62b2cac7ed8198b15735ed49ab1e5cf35480ba46 # v2.4.0
+        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@f6091c0113d1dcf9b98e269ee48e8a7e51b7bdd4 # v3.28.5
+        uses: github/codeql-action/upload-sarif@407ffafae6a767df3e0230c3df91b6443ae8df75 # v2.22.8
        with:
          sarif_file: results.sarif
--- a/.github/workflows/pitest-analyze-pr.yml
+++ b/.github/workflows/pitest-analyze-pr.yml
@@ -9,25 +9,19 @@ permissions:
  contents: read
 jobs:
  analyze-pr:
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
+      - name: Check out code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            api.adoptium.net:443
-            github.com:443
-            objects.githubusercontent.com:443
-            repo.maven.apache.org:443
-      - name: Check out code and set up JDK and Maven
-        uses: s4u/setup-maven-action@4f7fb9d9675e899ca81c6161dadbba0189a4ebb1 # v1.18.0
+          fetch-depth: 2
+          persist-credentials: false
+      - name: Set up JDK
+        uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
        with:
-          checkout-fetch-depth: 2
-          java-version: 17.0.13
-          java-distribution: temurin
-          maven-version: 3.9.9
+          java-version: 17.0.8
+          distribution: temurin
+          cache: maven
      - name: Run Pitest
        # By running with features `+GIT(from[HEAD~1]), +gitci`, Pitest only
        # analyzes lines changed in the associated pull request, as GitHub
@@ -38,7 +32,7 @@ jobs:
      - name: Aggregate Pitest reports
        run: mvn pitest-git:aggregate -DkilledEmoji=":tada:" -DmutantEmoji=":zombie:" -DtrailingText="Mutation testing report by [Pitest](https://pitest.org/). Review any surviving mutants by inspecting the line comments under [_Files changed_](${{ github.event.number }}/files)."
      - name: Upload Pitest reports as artifact
-        uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
+        uses: actions/upload-artifact@c7d193f32edcb7bfad88892161225aeda64e9392 # v4.0.0
        with:
          name: pitest-reports
          path: ./target/pit-reports-ci
--- a/.github/workflows/pitest-update-pr.yml
+++ b/.github/workflows/pitest-update-pr.yml
@@ -17,27 +17,20 @@ jobs:
      checks: write
      contents: read
      pull-requests: write
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
+      - name: Check out code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            api.adoptium.net:443
-            api.github.com:443
-            github.com:443
-            objects.githubusercontent.com:443
-            repo.maven.apache.org:443
-      - name: Check out code and set up JDK and Maven
-        uses: s4u/setup-maven-action@4f7fb9d9675e899ca81c6161dadbba0189a4ebb1 # v1.18.0
+          persist-credentials: false
+      - name: Set up JDK
+        uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
        with:
-          java-version: 17.0.13
-          java-distribution: temurin
-          maven-version: 3.9.9
+          java-version: 17.0.8
+          distribution: temurin
+          cache: maven
      - name: Download Pitest analysis artifact
-        uses: dawidd6/action-download-artifact@09f2f74827fd3a8607589e5ad7f9398816f540fe # v3.1.4
+        uses: dawidd6/action-download-artifact@e7466d1a7587ed14867642c2ca74b5bcc1e19a2d # v3.0.0
        with:
          workflow: ${{ github.event.workflow_run.workflow_id }}
          name: pitest-reports
--- a/.github/workflows/run-integration-tests.yml
+++ b/.github/workflows/run-integration-tests.yml
@@ -1,9 +1,9 @@
 # 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: Review whether then build matrix should also vary JDK or OS versions.
-# XXX: Support `/integration-test [name...]` comment syntax to specify the
-# subset of integration tests to run.
-# See this example of a dynamic build matrix:
+# 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:
@@ -16,48 +16,28 @@ jobs:
    name: On-demand integration test
    if: |
      github.event.issue.pull_request && contains(github.event.comment.body, '/integration-test')
-    runs-on: ubuntu-24.04
-    strategy:
-      matrix:
-        integration-test: [ "checkstyle", "metrics", "prometheus-java-client" ]
+    runs-on: ubuntu-22.04
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
+      - name: Check out code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            # XXX: After updating the validation build flags in
-            # `integration-tests/prometheus-java-client.sh`, review whether the
-            # Docker domains specified here can be dropped.
-            api.adoptium.net:443
-            auth.docker.io:443
-            checkstyle.org:443
-            example.com:80
-            github.com:443
-            objects.githubusercontent.com:443
-            oss.sonatype.org:443
-            production.cloudflare.docker.com:443
-            raw.githubusercontent.com:443
-            registry-1.docker.io:443
-            repo.maven.apache.org:443
-            repository.sonatype.org:443
-      - name: Check out code and set up JDK and Maven
-        uses: s4u/setup-maven-action@4f7fb9d9675e899ca81c6161dadbba0189a4ebb1 # v1.18.0
+          persist-credentials: false
+          ref: refs/pull/${{ github.event.issue.number }}/head
+      - name: Set up JDK
+        uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
        with:
-          checkout-ref: "refs/pull/${{ github.event.issue.number }}/head"
-          java-version: 17.0.13
-          java-distribution: temurin
-          maven-version: 3.9.9
+          java-version: 17.0.8
+          distribution: temurin
+          cache: maven
      - name: Install project to local Maven repository
        run: mvn -T1C install -DskipTests -Dverification.skip
      - name: Run integration test
-        run: xvfb-run "./integration-tests/${{ matrix.integration-test }}.sh" "${{ runner.temp }}/artifacts"
+        run: xvfb-run ./integration-tests/checkstyle-10.12.4.sh "${{ runner.temp }}/artifacts"
      - name: Upload artifacts on failure
        if: ${{ failure() }}
-        uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v4.6.0
+        uses: actions/upload-artifact@c7d193f32edcb7bfad88892161225aeda64e9392 # v4.0.0
        with:
-          name: "integration-test-${{ matrix.integration-test }}"
+          name: integration-test-checkstyle-10.12.4
          path: "${{ runner.temp }}/artifacts"
      - name: Remove installed project artifacts
-        run: mvn dependency:purge-local-repository -DmanualInclude='${project.groupId}' -DresolutionFuzziness=groupId
+        run: mvn build-helper:remove-project-artifact
--- a/.github/workflows/sonarcloud.yml
+++ b/.github/workflows/sonarcloud.yml
@@ -13,34 +13,22 @@ 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_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
+    if: github.event.pull_request.head.repo.full_name == github.repository
    permissions:
      contents: read
-    runs-on: ubuntu-24.04
+    runs-on: ubuntu-22.04
    steps:
-      - name: Install Harden-Runner
-        uses: step-security/harden-runner@cb605e52c26070c328afc4562f0b4ada7618a84e # v2.10.4
+      - name: Check out code
+        uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
        with:
-          disable-sudo: true
-          egress-policy: block
-          allowed-endpoints: >
-            analysis-sensorcache-eu-central-1-prod.s3.amazonaws.com:443
-            api.adoptium.net:443
-            api.nuget.org:443
-            ea6ne4j2sb.execute-api.eu-central-1.amazonaws.com:443
-            github.com:443
-            objects.githubusercontent.com:443
-            repo.maven.apache.org:443
-            sc-cleancode-sensorcache-eu-central-1-prod.s3.amazonaws.com:443
-            *.sonarcloud.io:443
-            sonarcloud.io:443
-      - name: Check out code and set up JDK and Maven
-        uses: s4u/setup-maven-action@4f7fb9d9675e899ca81c6161dadbba0189a4ebb1 # v1.18.0
+          fetch-depth: 0
+          persist-credentials: false
+      - name: Set up JDK
+        uses: actions/setup-java@387ac29b308b003ca37ba93a6cab5eb57c8f5f93 # v4.0.0
        with:
-          checkout-fetch-depth: 0
-          java-version: 17.0.13
-          java-distribution: temurin
-          maven-version: 3.9.9
+          java-version: 17.0.8
+          distribution: temurin
+          cache: maven
      - name: Create missing `test` directory
        # XXX: Drop this step in favour of actually having a test.
        run: mkdir refaster-compiler/src/test
--- a/.gitignore
+++ b/.gitignore
@@ -4,7 +4,6 @@
 .DS_Store
 .factorypath
 .idea
-!.idea/icon.svg
 .project
 .settings
 target
--- a/.idea/icon.svg
+++ b/.idea/icon.svg
@@ -1,65 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">
-<svg width="100%" height="100%" viewBox="0 0 1259 1199" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" xml:space="preserve" xmlns:serif="http://www.serif.com/" style="fill-rule:evenodd;clip-rule:evenodd;stroke-linejoin:round;stroke-miterlimit:2;">
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--- a/.renovaterc.json
+++ b/.renovaterc.json
@@ -3,30 +3,16 @@
  "extends": [
    "helpers:pinGitHubActionDigests"
  ],
-  "customManagers": [
-    {
-      "customType": "regex",
-      "fileMatch": [
-        "^integration-tests/.*(-init\\.patch|\\.sh)$"
-      ],
-      "matchStrings": [
-        "\\b(?<packageName>[a-z0-9_.-]+?:[a-z0-9_.-]+?):(?<currentValue>[^:]+?):[a-zA-Z0-9_-]+\\b",
-        "<version>(?<currentValue>.*?)<!-- Renovate: (?<packageName>.*?) --></version>"
-      ],
-      "datasourceTemplate": "maven"
-    }
-  ],
  "packageRules": [
    {
-      "matchPackageNames": [
-        "/^org\\.springframework:spring-framework-bom$/",
-        "/^org\\.springframework\\.boot:spring-boot[a-z-]*$/"
+      "matchPackagePatterns": [
+        "^org\\.springframework:spring-framework-bom$",
+        "^org\\.springframework\\.boot:spring-boot[a-z-]*$"
      ],
      "separateMinorPatch": true
    },
    {
-      "matchPackageNames": [
-        "dawidd6/action-download-artifact",
+      "matchDepNames": [
        "github/codeql-action",
        "ruby/setup-ruby"
      ],
--- a/LICENSE.md
+++ b/LICENSE.md
@@ -1,6 +1,6 @@
 MIT License

-Copyright (c) 2017-2024 Picnic Technologies BV
+Copyright (c) 2017-2023 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
--- a/README.md
+++ b/README.md
@@ -49,9 +49,7 @@ high-quality and consistent Java code_][picnic-blog-ep-post].
 ### Installation

 This library is built on top of [Error Prone][error-prone-orig-repo]. To use
-it, read the installation guide for Maven or Gradle below. The library requires
-that your build is executed using JDK 17 or above, but supports builds that
-[target][baeldung-java-source-target-options] older versions of Java.
+it, read the installation guide for Maven or Gradle below.

 #### Maven

@@ -67,8 +65,6 @@ that your build is executed using JDK 17 or above, but supports builds that
               <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. -->
@@ -98,6 +94,8 @@ that your build is executed using JDK 17 or above, but supports builds that
                           </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>
@@ -205,20 +203,19 @@ Relevant Maven build parameters:
  version of Error Prone. This is useful e.g. when testing a locally built
  Error Prone SNAPSHOT.
 - `-Perror-prone-fork` runs the build using Picnic's [Error Prone
-  fork][error-prone-fork-repo], hosted using [GitHub
-  Packages][error-prone-fork-packages]. This fork generally contains a few
-  changes on top of the latest Error Prone release. Using this profile
-  generally requires passing `-s settings.xml`, with [suitably
-  configured][github-packages-auth] `GITHUB_ACTOR` and `GITHUB_TOKEN`
-  environment variables.
+  fork][error-prone-fork-repo], hosted on [Jitpack][error-prone-fork-jitpack].
+  This fork generally contains a few changes on top of the latest Error Prone
+  release.
 - `-Pself-check` runs the checks defined by this project against itself.
+  Pending a release of [google/error-prone#3301][error-prone-pull-3301], this
+  flag must currently be used in combination with `-Perror-prone-fork`.

 Other highly relevant commands:

 - `mvn fmt:format` formats the code using
  [`google-java-format`][google-java-format].
 - [`./run-full-build.sh`][script-run-full-build] builds the project twice,
-  where the second pass validates compatibility with Picnic's [Error Prone
+  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
@@ -236,9 +233,8 @@ Other highly relevant commands:
  against _all_ code in the current working directory. For more information
  check the [PIT Maven plugin][pitest-maven].

-Opening the project in IntelliJ IDEA may require running `mvn clean install`
-first. Additionally, when running the project's tests using the IDE, you might
-see the following error:
+When running the project's tests in IntelliJ IDEA, you might see the following
+error:

 ```
 java: exporting a package from system module jdk.compiler is not allowed with --release
@@ -267,7 +263,6 @@ guidelines][contributing].
 If you want to report a security vulnerability, please do so through a private
 channel; please see our [security policy][security] for details.

-[baeldung-java-source-target-options]: https://www.baeldung.com/java-source-target-options
 [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
@@ -276,14 +271,14 @@ channel; please see our [security policy][security] for details.
 [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-packages]: https://github.com/PicnicSupermarket/error-prone/packages
+[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.yml/badge.svg
 [github-actions-build-master]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/build.yml?query=branch:master&event=push
-[github-packages-auth]: https://docs.github.com/en/packages/working-with-a-github-packages-registry/working-with-the-apache-maven-registry#authenticating-to-github-packages
 [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
@@ -304,7 +299,7 @@ channel; please see our [security policy][security] for details.
 [refaster]: https://errorprone.info/docs/refaster
 [refaster-rules-bigdecimal]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BigDecimalRules.java
 [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/endpoint?url=https://raw.githubusercontent.com/jvm-repo-rebuild/reproducible-central/master/content/tech/picnic/error-prone-support/error-prone-support/badge.json
+[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
--- a/documentation-support/pom.xml
+++ b/documentation-support/pom.xml
@@ -5,23 +5,31 @@
    <parent>
        <groupId>tech.picnic.error-prone-support</groupId>
        <artifactId>error-prone-support</artifactId>
-        <version>0.20.0</version>
+        <version>0.14.1-SNAPSHOT</version>
    </parent>

    <artifactId>documentation-support</artifactId>

    <name>Picnic :: Error Prone Support :: Documentation Support</name>
    <description>Data extraction support for the purpose of documentation generation.</description>
-    <url>https://error-prone.picnic.tech</url>

    <dependencies>
        <dependency>
-            <groupId>${project.groupId}</groupId>
-            <artifactId>error-prone-utils</artifactId>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_annotation</artifactId>
        </dependency>
        <dependency>
-            <groupId>${project.groupId}</groupId>
-            <artifactId>refaster-test-support</artifactId>
+            <groupId>${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>
@@ -32,14 +40,6 @@
            <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>
@@ -54,24 +54,6 @@
            <artifactId>auto-value-annotations</artifactId>
            <scope>provided</scope>
        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_annotation</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_annotations</artifactId>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_check_api</artifactId>
-        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_test_helpers</artifactId>
-            <scope>test</scope>
-        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
@@ -91,8 +73,6 @@
            <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>
--- a/documentation-support/src/main/java/tech/picnic/errorprone/documentation/BugPatternExtractor.java
+++ b/documentation-support/src/main/java/tech/picnic/errorprone/documentation/BugPatternExtractor.java
@@ -4,7 +4,6 @@ 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;
@@ -18,7 +17,6 @@ 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;
@@ -47,8 +45,7 @@ public final class BugPatternExtractor implements Extractor<BugPatternDocumentat
    }

    return Optional.of(
-        BugPatternDocumentation.create(
-            state.getPath().getCompilationUnit().getSourceFile().toUri(),
+        new AutoValue_BugPatternExtractor_BugPatternDocumentation(
            symbol.getQualifiedName().toString(),
            annotation.name().isEmpty() ? tree.getSimpleName().toString() : annotation.name(),
            ImmutableList.copyOf(annotation.altNames()),
@@ -94,36 +91,7 @@ public final class BugPatternExtractor implements Extractor<BugPatternDocumentat
  }

  @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();
--- a/documentation-support/src/main/java/tech/picnic/errorprone/documentation/BugPatternTestExtractor.java
+++ b/documentation-support/src/main/java/tech/picnic/errorprone/documentation/BugPatternTestExtractor.java
@@ -2,15 +2,9 @@ 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.Objects.requireNonNull;
 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;
@@ -22,12 +16,13 @@ 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.Objects;
 import java.util.Optional;
+import org.jspecify.annotations.NonNull;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.BugPatternTestCases;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCases;

 /**
 * An {@link Extractor} that describes how to extract data from classes that test a {@code
@@ -40,7 +35,7 @@ import tech.picnic.errorprone.documentation.BugPatternTestExtractor.BugPatternTe
@Immutable
@AutoService(Extractor.class)
@SuppressWarnings("rawtypes" /* See https://github.com/google/auto/issues/870. */)
-public final class BugPatternTestExtractor implements Extractor<BugPatternTestCases> {
+public final class BugPatternTestExtractor implements Extractor<TestCases> {
  /** Instantiates a new {@link BugPatternTestExtractor} instance. */
  public BugPatternTestExtractor() {}

@@ -50,7 +45,7 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
  }

  @Override
-  public Optional<BugPatternTestCases> tryExtract(ClassTree tree, VisitorState state) {
+  public Optional<TestCases> tryExtract(ClassTree tree, VisitorState state) {
    BugPatternTestCollector collector = new BugPatternTestCollector();

    collector.scan(tree, state);
@@ -59,10 +54,8 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
        .filter(not(ImmutableList::isEmpty))
        .map(
            tests ->
-                new AutoValue_BugPatternTestExtractor_BugPatternTestCases(
-                    state.getPath().getCompilationUnit().getSourceFile().toUri(),
-                    ASTHelpers.getSymbol(tree).className(),
-                    tests));
+                new AutoValue_BugPatternTestExtractor_TestCases(
+                    ASTHelpers.getSymbol(tree).className(), tests));
  }

  private static final class BugPatternTestCollector
@@ -95,10 +88,10 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
            .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper.ExpectOutput")
            .namedAnyOf("addOutputLines", "expectUnchanged");

-    private final List<BugPatternTestCase> collectedBugPatternTestCases = new ArrayList<>();
+    private final List<TestCase> collectedTestCases = new ArrayList<>();

-    private ImmutableList<BugPatternTestCase> getCollectedTests() {
-      return ImmutableList.copyOf(collectedBugPatternTestCases);
+    private ImmutableList<TestCase> getCollectedTests() {
+      return ImmutableList.copyOf(collectedTestCases);
    }

    @Override
@@ -110,14 +103,14 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
                classUnderTest -> {
                  List<TestEntry> entries = new ArrayList<>();
                  if (isReplacementTest) {
-                    extractReplacementBugPatternTestCases(node, entries, state);
+                    extractReplacementTestCases(node, entries, state);
                  } else {
-                    extractIdentificationBugPatternTestCases(node, entries, state);
+                    extractIdentificationTestCases(node, entries, state);
                  }

                  if (!entries.isEmpty()) {
-                    collectedBugPatternTestCases.add(
-                        new AutoValue_BugPatternTestExtractor_BugPatternTestCase(
+                    collectedTestCases.add(
+                        new AutoValue_BugPatternTestExtractor_TestCase(
                            classUnderTest, ImmutableList.copyOf(entries).reverse()));
                  }
                });
@@ -135,12 +128,12 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
      }

      ExpressionTree receiver = ASTHelpers.getReceiver(tree);
-      return receiver instanceof MethodInvocationTree methodInvocation
-          ? getClassUnderTest(methodInvocation, state)
+      return receiver instanceof MethodInvocationTree
+          ? getClassUnderTest((MethodInvocationTree) receiver, state)
          : Optional.empty();
    }

-    private static void extractIdentificationBugPatternTestCases(
+    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);
@@ -154,12 +147,12 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
      }

      ExpressionTree receiver = ASTHelpers.getReceiver(tree);
-      if (receiver instanceof MethodInvocationTree methodInvocation) {
-        extractIdentificationBugPatternTestCases(methodInvocation, sink, state);
+      if (receiver instanceof MethodInvocationTree) {
+        extractIdentificationTestCases((MethodInvocationTree) receiver, sink, state);
      }
    }

-    private static void extractReplacementBugPatternTestCases(
+    private static void extractReplacementTestCases(
        MethodInvocationTree tree, List<TestEntry> sink, VisitorState state) {
      if (REPLACEMENT_OUTPUT_SOURCE_LINES.matches(tree, state)) {
        /*
@@ -167,7 +160,7 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
         * 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);
+        MethodInvocationTree inputTree = (MethodInvocationTree) requireNonNull(ASTHelpers.getReceiver(tree));

        String path = ASTHelpers.constValue(inputTree.getArguments().get(0), String.class);
        Optional<String> inputCode = getSourceCode(inputTree);
@@ -184,8 +177,8 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
      }

      ExpressionTree receiver = ASTHelpers.getReceiver(tree);
-      if (receiver instanceof MethodInvocationTree methodInvocation) {
-        extractReplacementBugPatternTestCases(methodInvocation, sink, state);
+      if (receiver instanceof MethodInvocationTree) {
+        extractReplacementTestCases((MethodInvocationTree) receiver, sink, state);
      }
    }

@@ -208,80 +201,32 @@ public final class BugPatternTestExtractor implements Extractor<BugPatternTestCa
  }

  @AutoValue
-  @JsonDeserialize(as = AutoValue_BugPatternTestExtractor_BugPatternTestCases.class)
-  abstract static class BugPatternTestCases {
-    static BugPatternTestCases create(
-        URI source, String testClass, ImmutableList<BugPatternTestCase> testCases) {
-      return new AutoValue_BugPatternTestExtractor_BugPatternTestCases(
-          source, testClass, testCases);
-    }
-
-    abstract URI source();
-
+  abstract static class TestCases {
    abstract String testClass();

-    abstract ImmutableList<BugPatternTestCase> testCases();
+    abstract ImmutableList<TestCase> testCases();
  }

  @AutoValue
-  @JsonDeserialize(as = AutoValue_BugPatternTestExtractor_BugPatternTestCase.class)
-  abstract static class BugPatternTestCase {
-    static BugPatternTestCase create(String classUnderTest, ImmutableList<TestEntry> entries) {
-      return new AutoValue_BugPatternTestExtractor_BugPatternTestCase(classUnderTest, entries);
-    }
-
+  abstract static class TestCase {
    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();
  }
+
+  @AutoValue
+  abstract static class IdentificationTestEntry implements TestEntry {
+    abstract String code();
+  }
 }
--- a/documentation-support/src/main/java/tech/picnic/errorprone/documentation/DocumentationGenerator.java
+++ b/documentation-support/src/main/java/tech/picnic/errorprone/documentation/DocumentationGenerator.java
@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.documentation;

 import static com.google.common.base.Preconditions.checkArgument;
+import static java.util.Objects.requireNonNull;

 import com.google.auto.service.AutoService;
 import com.google.common.annotations.VisibleForTesting;
@@ -46,7 +47,7 @@ public final class DocumentationGenerator implements Plugin {
    checkArgument(
        matcher.matches(), "'%s' must be of the form '%s=<value>'", pathArg, OUTPUT_DIRECTORY_FLAG);

-    String path = matcher.group(1);
+    String path = requireNonNull(matcher.group(1), "Path must be present");
    try {
      return Path.of(path);
    } catch (InvalidPathException e) {
--- a/documentation-support/src/main/java/tech/picnic/errorprone/documentation/DocumentationGeneratorTaskListener.java
+++ b/documentation-support/src/main/java/tech/picnic/errorprone/documentation/DocumentationGeneratorTaskListener.java
@@ -1,5 +1,11 @@
 package tech.picnic.errorprone.documentation;

+import static java.nio.charset.StandardCharsets.UTF_8;
+import static java.util.Objects.requireNonNull;
+
+import com.fasterxml.jackson.annotation.JsonAutoDetect.Visibility;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.databind.ObjectMapper;
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.VisitorState;
 import com.sun.source.tree.ClassTree;
@@ -10,10 +16,14 @@ import com.sun.source.util.TaskListener;
 import com.sun.source.util.TreePath;
 import com.sun.tools.javac.api.JavacTrees;
 import com.sun.tools.javac.util.Context;
+import java.io.File;
+import java.io.FileWriter;
 import java.io.IOException;
+import java.io.UncheckedIOException;
 import java.net.URI;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
 import java.util.ServiceLoader;
 import javax.tools.JavaFileObject;

@@ -30,6 +40,9 @@ final class DocumentationGeneratorTaskListener implements TaskListener {
              ServiceLoader.load(
                  Extractor.class, DocumentationGeneratorTaskListener.class.getClassLoader()));

+  private static final ObjectMapper OBJECT_MAPPER =
+      new ObjectMapper().setVisibility(PropertyAccessor.FIELD, Visibility.ANY);
+
  private final Context context;
  private final Path docsPath;

@@ -81,11 +94,19 @@ final class DocumentationGeneratorTaskListener implements TaskListener {
    }
  }

-  private <T> void writeToFile(String identifier, String className, T data) {
-    Json.write(docsPath.resolve(String.format("%s-%s.json", identifier, className)), data);
+  private <T extends Object> void writeToFile(String identifier, String className, T data) {
+    File file = docsPath.resolve(String.format("%s-%s.json", identifier, className)).toFile();
+
+    try (FileWriter fileWriter = new FileWriter(file, UTF_8)) {
+      OBJECT_MAPPER.writeValue(fileWriter, data);
+    } catch (IOException e) {
+      throw new UncheckedIOException(String.format("Cannot write to file '%s'", file.getPath()), e);
+    }
  }

  private static String getSimpleClassName(URI path) {
-    return Path.of(path).getFileName().toString().replace(".java", "");
+    return requireNonNull(Paths.get(path).getFileName(), "Path lacks filename")
+        .toString()
+        .replace(".java", "");
  }
 }
--- a/documentation-support/src/main/java/tech/picnic/errorprone/documentation/Json.java
+++ b/documentation-support/src/main/java/tech/picnic/errorprone/documentation/Json.java
@@ -1,45 +0,0 @@
-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);
-  }
-}
--- a/documentation-support/src/main/java/tech/picnic/errorprone/documentation/RefasterRuleCollectionTestExtractor.java
+++ b/documentation-support/src/main/java/tech/picnic/errorprone/documentation/RefasterRuleCollectionTestExtractor.java
@@ -1,176 +0,0 @@
-package tech.picnic.errorprone.documentation;
-
-import static com.google.common.collect.ImmutableList.toImmutableList;
-import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
-import static java.util.stream.Collectors.joining;
-
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.google.auto.service.AutoService;
-import com.google.auto.value.AutoValue;
-import com.google.common.base.Splitter;
-import com.google.common.base.Supplier;
-import com.google.common.base.VerifyException;
-import com.google.common.collect.ImmutableList;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.annotations.FormatMethod;
-import com.google.errorprone.annotations.Immutable;
-import com.google.errorprone.matchers.Matcher;
-import com.sun.source.tree.ClassTree;
-import com.sun.source.tree.MethodTree;
-import java.net.URI;
-import java.util.Optional;
-import java.util.regex.Pattern;
-import tech.picnic.errorprone.documentation.RefasterRuleCollectionTestExtractor.RefasterTestCases;
-import tech.picnic.errorprone.utils.SourceCode;
-
-/**
- * An {@link Extractor} that describes how to extract data from Refaster rule input and output test
- * classes.
- */
-// XXX: Drop this extractor if/when the Refaster test framework is reimplemented such that tests can
-// be located alongside rules, rather than in two additional resource files as currently required by
-// `RefasterRuleCollection`.
-@Immutable
-@AutoService(Extractor.class)
-@SuppressWarnings("rawtypes" /* See https://github.com/google/auto/issues/870. */)
-public final class RefasterRuleCollectionTestExtractor implements Extractor<RefasterTestCases> {
-  private static final Matcher<ClassTree> IS_REFASTER_RULE_COLLECTION_TEST_CASE =
-      isSubtypeOf("tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase");
-  private static final Pattern TEST_CLASS_NAME_PATTERN = Pattern.compile("(.*)Test");
-  private static final Pattern TEST_CLASS_FILE_NAME_PATTERN =
-      Pattern.compile(".*(Input|Output)\\.java");
-  private static final Pattern TEST_METHOD_NAME_PATTERN = Pattern.compile("test(.*)");
-  private static final String LINE_SEPARATOR = "\n";
-  private static final Splitter LINE_SPLITTER = Splitter.on(LINE_SEPARATOR);
-
-  /** Instantiates a new {@link RefasterRuleCollectionTestExtractor} instance. */
-  public RefasterRuleCollectionTestExtractor() {}
-
-  @Override
-  public String identifier() {
-    return "refaster-rule-collection-test";
-  }
-
-  @Override
-  public Optional<RefasterTestCases> tryExtract(ClassTree tree, VisitorState state) {
-    if (!IS_REFASTER_RULE_COLLECTION_TEST_CASE.matches(tree, state)) {
-      return Optional.empty();
-    }
-
-    URI sourceFile = state.getPath().getCompilationUnit().getSourceFile().toUri();
-    return Optional.of(
-        RefasterTestCases.create(
-            sourceFile,
-            getRuleCollectionName(tree),
-            isInputFile(sourceFile),
-            getRefasterTestCases(tree, state)));
-  }
-
-  private static String getRuleCollectionName(ClassTree tree) {
-    String className = tree.getSimpleName().toString();
-
-    // XXX: Instead of throwing an error here, it'd be nicer to have a bug checker validate key
-    // aspects of `RefasterRuleCollectionTestCase` subtypes.
-    return tryExtractPatternGroup(className, TEST_CLASS_NAME_PATTERN)
-        .orElseThrow(
-            violation(
-                "Refaster rule collection test class name '%s' does not match '%s'",
-                className, TEST_CLASS_NAME_PATTERN));
-  }
-
-  private static boolean isInputFile(URI sourceFile) {
-    String path = sourceFile.getPath();
-
-    // XXX: Instead of throwing an error here, it'd be nicer to have a bug checker validate key
-    // aspects of `RefasterRuleCollectionTestCase` subtypes.
-    return "Input"
-        .equals(
-            tryExtractPatternGroup(path, TEST_CLASS_FILE_NAME_PATTERN)
-                .orElseThrow(
-                    violation(
-                        "Refaster rule collection test file name '%s' does not match '%s'",
-                        path, TEST_CLASS_FILE_NAME_PATTERN)));
-  }
-
-  private static ImmutableList<RefasterTestCase> getRefasterTestCases(
-      ClassTree tree, VisitorState state) {
-    return tree.getMembers().stream()
-        .filter(MethodTree.class::isInstance)
-        .map(MethodTree.class::cast)
-        .flatMap(m -> tryExtractRefasterTestCase(m, state).stream())
-        .collect(toImmutableList());
-  }
-
-  private static Optional<RefasterTestCase> tryExtractRefasterTestCase(
-      MethodTree method, VisitorState state) {
-    return tryExtractPatternGroup(method.getName().toString(), TEST_METHOD_NAME_PATTERN)
-        .map(name -> RefasterTestCase.create(name, getFormattedSource(method, state)));
-  }
-
-  /**
-   * Returns the source code for the specified method.
-   *
-   * @implNote This operation attempts to trim leading whitespace, such that the start and end of
-   *     the method declaration are aligned. The implemented heuristic assumes that the code is
-   *     formatted using Google Java Format.
-   */
-  // XXX: Leading Javadoc and other comments are currently not extracted. Consider fixing this.
-  private static String getFormattedSource(MethodTree method, VisitorState state) {
-    String source = SourceCode.treeToString(method, state);
-    int finalNewline = source.lastIndexOf(LINE_SEPARATOR);
-    if (finalNewline < 0) {
-      return source;
-    }
-
-    int indentation = Math.max(0, source.lastIndexOf(' ') - finalNewline);
-    String prefixToStrip = " ".repeat(indentation);
-
-    return LINE_SPLITTER
-        .splitToStream(source)
-        .map(line -> line.startsWith(prefixToStrip) ? line.substring(indentation) : line)
-        .collect(joining(LINE_SEPARATOR));
-  }
-
-  private static Optional<String> tryExtractPatternGroup(String input, Pattern pattern) {
-    java.util.regex.Matcher matcher = pattern.matcher(input);
-    return matcher.matches() ? Optional.of(matcher.group(1)) : Optional.empty();
-  }
-
-  @FormatMethod
-  private static Supplier<VerifyException> violation(String format, Object... args) {
-    return () -> new VerifyException(String.format(format, args));
-  }
-
-  @AutoValue
-  @JsonDeserialize(as = AutoValue_RefasterRuleCollectionTestExtractor_RefasterTestCases.class)
-  abstract static class RefasterTestCases {
-    static RefasterTestCases create(
-        URI source,
-        String ruleCollection,
-        boolean isInput,
-        ImmutableList<RefasterTestCase> testCases) {
-      return new AutoValue_RefasterRuleCollectionTestExtractor_RefasterTestCases(
-          source, ruleCollection, isInput, testCases);
-    }
-
-    abstract URI source();
-
-    abstract String ruleCollection();
-
-    abstract boolean isInput();
-
-    abstract ImmutableList<RefasterTestCase> testCases();
-  }
-
-  @AutoValue
-  @JsonDeserialize(as = AutoValue_RefasterRuleCollectionTestExtractor_RefasterTestCase.class)
-  abstract static class RefasterTestCase {
-    static RefasterTestCase create(String name, String content) {
-      return new AutoValue_RefasterRuleCollectionTestExtractor_RefasterTestCase(name, content);
-    }
-
-    abstract String name();
-
-    abstract String content();
-  }
-}
--- a/documentation-support/src/test/java/tech/picnic/errorprone/documentation/BugPatternExtractorTest.java
+++ b/documentation-support/src/test/java/tech/picnic/errorprone/documentation/BugPatternExtractorTest.java
@@ -1,17 +1,13 @@
 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 java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;

-import com.google.common.collect.ImmutableList;
-import com.google.errorprone.BugPattern;
-import java.net.URI;
+import com.google.common.io.Resources;
+import java.io.IOException;
 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
@@ -27,7 +23,7 @@ final class BugPatternExtractorTest {
  }

  @Test
-  void minimalBugPattern(@TempDir Path outputDirectory) {
+  void minimalBugPattern(@TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "MinimalBugChecker.java",
@@ -40,25 +36,11 @@ final class BugPatternExtractorTest {
        "@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())));
+    verifyGeneratedFileContent(outputDirectory, "MinimalBugChecker");
  }

  @Test
-  void completeBugPattern(@TempDir Path outputDirectory) {
+  void completeBugPattern(@TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "CompleteBugChecker.java",
@@ -82,25 +64,11 @@ final class BugPatternExtractorTest {
        "    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")));
+    verifyGeneratedFileContent(outputDirectory, "CompleteBugChecker");
  }

  @Test
-  void undocumentedSuppressionBugPattern(@TempDir Path outputDirectory) {
+  void undocumentedSuppressionBugPattern(@TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "UndocumentedSuppressionBugPattern.java",
@@ -116,27 +84,23 @@ final class BugPatternExtractorTest {
        "    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()));
+    verifyGeneratedFileContent(outputDirectory, "UndocumentedSuppressionBugPattern");
  }

-  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));
+  private static void verifyGeneratedFileContent(Path outputDirectory, String testClass)
+      throws IOException {
+    String resourceName = String.format("bugpattern-%s.json", testClass);
+    assertThat(outputDirectory.resolve(resourceName))
+        .content(UTF_8)
+        .isEqualToIgnoringWhitespace(
+            getResource(
+                String.join("-", BugPatternExtractorTest.class.getSimpleName(), resourceName)));
+  }
+
+  // XXX: Once we support only JDK 15+, drop this method in favour of including the resources as
+  // text blocks in this class.
+  private static String getResource(String resourceName) throws IOException {
+    return Resources.toString(
+        Resources.getResource(BugPatternExtractorTest.class, resourceName), UTF_8);
  }
 }
--- a/documentation-support/src/test/java/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest.java
+++ b/documentation-support/src/test/java/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest.java
@@ -1,16 +1,13 @@
 package tech.picnic.errorprone.documentation;

+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;

-import com.google.common.collect.ImmutableList;
-import java.net.URI;
+import com.google.common.io.Resources;
+import java.io.IOException;
 import java.nio.file.Path;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.BugPatternTestCase;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.BugPatternTestCases;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.IdentificationTestEntry;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.ReplacementTestEntry;

 final class BugPatternTestExtractorTest {
  @Test
@@ -249,7 +246,7 @@ final class BugPatternTestExtractorTest {
  }

  @Test
-  void singleFileCompilationTestHelper(@TempDir Path outputDirectory) {
+  void singleFileCompilationTestHelper(@TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "SingleFileCompilationTestHelperTest.java",
@@ -266,22 +263,12 @@ final class BugPatternTestExtractorTest {
        "  }",
        "}");

-    verifyGeneratedFileContent(
-        outputDirectory,
-        "SingleFileCompilationTestHelperTest",
-        BugPatternTestCases.create(
-            URI.create("file:///SingleFileCompilationTestHelperTest.java"),
-            "SingleFileCompilationTestHelperTest",
-            ImmutableList.of(
-                BugPatternTestCase.create(
-                    "SingleFileCompilationTestHelperTest.TestChecker",
-                    ImmutableList.of(
-                        IdentificationTestEntry.create(
-                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))))));
+    verifyGeneratedFileContent(outputDirectory, "SingleFileCompilationTestHelperTest");
  }

  @Test
-  void singleFileCompilationTestHelperWithSetArgs(@TempDir Path outputDirectory) {
+  void singleFileCompilationTestHelperWithSetArgs(@TempDir Path outputDirectory)
+      throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "SingleFileCompilationTestHelperWithSetArgsTest.java",
@@ -299,22 +286,11 @@ final class BugPatternTestExtractorTest {
        "  }",
        "}");

-    verifyGeneratedFileContent(
-        outputDirectory,
-        "SingleFileCompilationTestHelperWithSetArgsTest",
-        BugPatternTestCases.create(
-            URI.create("file:///SingleFileCompilationTestHelperWithSetArgsTest.java"),
-            "SingleFileCompilationTestHelperWithSetArgsTest",
-            ImmutableList.of(
-                BugPatternTestCase.create(
-                    "SingleFileCompilationTestHelperWithSetArgsTest.TestChecker",
-                    ImmutableList.of(
-                        IdentificationTestEntry.create(
-                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))))));
+    verifyGeneratedFileContent(outputDirectory, "SingleFileCompilationTestHelperWithSetArgsTest");
  }

  @Test
-  void multiFileCompilationTestHelper(@TempDir Path outputDirectory) {
+  void multiFileCompilationTestHelper(@TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "MultiFileCompilationTestHelperTest.java",
@@ -332,24 +308,11 @@ final class BugPatternTestExtractorTest {
        "  }",
        "}");

-    verifyGeneratedFileContent(
-        outputDirectory,
-        "MultiFileCompilationTestHelperTest",
-        BugPatternTestCases.create(
-            URI.create("file:///MultiFileCompilationTestHelperTest.java"),
-            "MultiFileCompilationTestHelperTest",
-            ImmutableList.of(
-                BugPatternTestCase.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"))))));
+    verifyGeneratedFileContent(outputDirectory, "MultiFileCompilationTestHelperTest");
  }

  @Test
-  void singleFileBugCheckerRefactoringTestHelper(@TempDir Path outputDirectory) {
+  void singleFileBugCheckerRefactoringTestHelper(@TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "SingleFileBugCheckerRefactoringTestHelperTest.java",
@@ -367,23 +330,12 @@ final class BugPatternTestExtractorTest {
        "  }",
        "}");

-    verifyGeneratedFileContent(
-        outputDirectory,
-        "SingleFileBugCheckerRefactoringTestHelperTest",
-        BugPatternTestCases.create(
-            URI.create("file:///SingleFileBugCheckerRefactoringTestHelperTest.java"),
-            "SingleFileBugCheckerRefactoringTestHelperTest",
-            ImmutableList.of(
-                BugPatternTestCase.create(
-                    "SingleFileBugCheckerRefactoringTestHelperTest.TestChecker",
-                    ImmutableList.of(
-                        ReplacementTestEntry.create(
-                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+    verifyGeneratedFileContent(outputDirectory, "SingleFileBugCheckerRefactoringTestHelperTest");
  }

  @Test
  void singleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestMode(
-      @TempDir Path outputDirectory) {
+      @TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.java",
@@ -407,21 +359,11 @@ final class BugPatternTestExtractorTest {

    verifyGeneratedFileContent(
        outputDirectory,
-        "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest",
-        BugPatternTestCases.create(
-            URI.create(
-                "file:///SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.java"),
-            "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest",
-            ImmutableList.of(
-                BugPatternTestCase.create(
-                    "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.TestChecker",
-                    ImmutableList.of(
-                        ReplacementTestEntry.create(
-                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+        "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest");
  }

  @Test
-  void multiFileBugCheckerRefactoringTestHelper(@TempDir Path outputDirectory) {
+  void multiFileBugCheckerRefactoringTestHelper(@TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "MultiFileBugCheckerRefactoringTestHelperTest.java",
@@ -441,24 +383,12 @@ final class BugPatternTestExtractorTest {
        "  }",
        "}");

-    verifyGeneratedFileContent(
-        outputDirectory,
-        "MultiFileBugCheckerRefactoringTestHelperTest",
-        BugPatternTestCases.create(
-            URI.create("file:///MultiFileBugCheckerRefactoringTestHelperTest.java"),
-            "MultiFileBugCheckerRefactoringTestHelperTest",
-            ImmutableList.of(
-                BugPatternTestCase.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"))))));
+    verifyGeneratedFileContent(outputDirectory, "MultiFileBugCheckerRefactoringTestHelperTest");
  }

  @Test
-  void compilationAndBugCheckerRefactoringTestHelpers(@TempDir Path outputDirectory) {
+  void compilationAndBugCheckerRefactoringTestHelpers(@TempDir Path outputDirectory)
+      throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "CompilationAndBugCheckerRefactoringTestHelpersTest.java",
@@ -482,27 +412,12 @@ final class BugPatternTestExtractorTest {
        "}");

    verifyGeneratedFileContent(
-        outputDirectory,
-        "CompilationAndBugCheckerRefactoringTestHelpersTest",
-        BugPatternTestCases.create(
-            URI.create("file:///CompilationAndBugCheckerRefactoringTestHelpersTest.java"),
-            "CompilationAndBugCheckerRefactoringTestHelpersTest",
-            ImmutableList.of(
-                BugPatternTestCase.create(
-                    "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
-                    ImmutableList.of(
-                        IdentificationTestEntry.create(
-                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))),
-                BugPatternTestCase.create(
-                    "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
-                    ImmutableList.of(
-                        ReplacementTestEntry.create(
-                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+        outputDirectory, "CompilationAndBugCheckerRefactoringTestHelpersTest");
  }

  @Test
  void compilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNames(
-      @TempDir Path outputDirectory) {
+      @TempDir Path outputDirectory) throws IOException {
    Compilation.compileWithDocumentationGenerator(
        outputDirectory,
        "CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.java",
@@ -531,28 +446,23 @@ final class BugPatternTestExtractorTest {

    verifyGeneratedFileContent(
        outputDirectory,
-        "CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest",
-        BugPatternTestCases.create(
-            URI.create(
-                "file:///CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.java"),
-            "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest",
-            ImmutableList.of(
-                BugPatternTestCase.create(
-                    "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker",
-                    ImmutableList.of(
-                        IdentificationTestEntry.create(
-                            "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))),
-                BugPatternTestCase.create(
-                    "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker2",
-                    ImmutableList.of(
-                        ReplacementTestEntry.create(
-                            "A.java", "class A {}\n", "class A { /* This is a change. */ }\n"))))));
+        "CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest");
  }

-  private static void verifyGeneratedFileContent(
-      Path outputDirectory, String testClass, BugPatternTestCases expected) {
-    assertThat(outputDirectory.resolve(String.format("bugpattern-test-%s.json", testClass)))
-        .exists()
-        .returns(expected, path -> Json.read(path, BugPatternTestCases.class));
+  private static void verifyGeneratedFileContent(Path outputDirectory, String testClass)
+      throws IOException {
+    String resourceName = String.format("bugpattern-test-%s.json", testClass);
+    assertThat(outputDirectory.resolve(resourceName))
+        .content(UTF_8)
+        .isEqualToIgnoringWhitespace(
+            getResource(
+                String.join("-", BugPatternTestExtractorTest.class.getSimpleName(), resourceName)));
+  }
+
+  // XXX: Once we support only JDK 15+, drop this method in favour of including the resources as
+  // text blocks in this class.
+  private static String getResource(String resourceName) throws IOException {
+    return Resources.toString(
+        Resources.getResource(BugPatternTestExtractorTest.class, resourceName), UTF_8);
  }
 }
--- a/documentation-support/src/test/java/tech/picnic/errorprone/documentation/Compilation.java
+++ b/documentation-support/src/test/java/tech/picnic/errorprone/documentation/Compilation.java
@@ -8,6 +8,8 @@ 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.io.IOException;
+import java.io.UncheckedIOException;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
@@ -53,22 +55,25 @@ public final class Compilation {
  }

  private static void compile(ImmutableList<String> options, JavaFileObject javaFileObject) {
-    JavacFileManager javacFileManager = FileManagers.testFileManager();
-    JavaCompiler compiler = JavacTool.create();
+    try (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));
+      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();
+      Boolean result = task.call();
+      assertThat(diagnostics).isEmpty();
+      assertThat(result).isTrue();
+    } catch (IOException e) {
+      throw new UncheckedIOException("Failed to close `JavaCompiler`", e);
+    }
  }
 }
--- a/documentation-support/src/test/java/tech/picnic/errorprone/documentation/DocumentationGeneratorTaskListenerTest.java
+++ b/documentation-support/src/test/java/tech/picnic/errorprone/documentation/DocumentationGeneratorTaskListenerTest.java
@@ -10,6 +10,7 @@ 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;
@@ -40,8 +41,7 @@ final class DocumentationGeneratorTaskListenerTest {
                entry ->
                    AclEntry.newBuilder(entry)
                        .setPermissions(
-                            Sets.difference(
-                                entry.permissions(), Sets.immutableEnumSet(ADD_SUBDIRECTORY)))
+                            Sets.difference(entry.permissions(), ImmutableSet.of(ADD_SUBDIRECTORY)))
                        .build())
            .collect(toImmutableList()));

@@ -93,20 +93,13 @@ final class DocumentationGeneratorTaskListenerTest {
        "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"
-              ]
-            }
-            """);
+            "{\"className\":\"DocumentationGeneratorTaskListenerTestClass\",\"path\":[\"CLASS: DocumentationGeneratorTaskListenerTestClass\",\"COMPILATION_UNIT\"]}");
  }

  @Immutable
@@ -132,8 +125,8 @@ final class DocumentationGeneratorTaskListenerTest {
    }

    private static String describeTree(Tree tree) {
-      return (tree instanceof ClassTree clazz)
-          ? String.join(": ", String.valueOf(tree.getKind()), clazz.getSimpleName())
+      return (tree instanceof ClassTree)
+          ? String.join(": ", String.valueOf(tree.getKind()), ((ClassTree) tree).getSimpleName())
          : tree.getKind().toString();
    }
  }
--- a/documentation-support/src/test/java/tech/picnic/errorprone/documentation/JsonTest.java
+++ b/documentation-support/src/test/java/tech/picnic/errorprone/documentation/JsonTest.java
@@ -1,62 +0,0 @@
-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();
-  }
-}
--- a/documentation-support/src/test/java/tech/picnic/errorprone/documentation/RefasterRuleCollectionTestExtractorTest.java
+++ b/documentation-support/src/test/java/tech/picnic/errorprone/documentation/RefasterRuleCollectionTestExtractorTest.java
@@ -1,166 +0,0 @@
-package tech.picnic.errorprone.documentation;
-
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatThrownBy;
-
-import com.google.common.base.VerifyException;
-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.RefasterRuleCollectionTestExtractor.RefasterTestCase;
-import tech.picnic.errorprone.documentation.RefasterRuleCollectionTestExtractor.RefasterTestCases;
-
-final class RefasterRuleCollectionTestExtractorTest {
-  @Test
-  void noRefasterRuleTest(@TempDir Path outputDirectory) {
-    Compilation.compileWithDocumentationGenerator(
-        outputDirectory, "NoRefasterRuleTest.java", "public final class NoRefasterRuleTest {}");
-
-    assertThat(outputDirectory.toAbsolutePath()).isEmptyDirectory();
-  }
-
-  @Test
-  void invalidTestClassName(@TempDir Path outputDirectory) {
-    assertThatThrownBy(
-            () ->
-                Compilation.compileWithDocumentationGenerator(
-                    outputDirectory,
-                    "InvalidTestClassNameInput.java",
-                    "import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;",
-                    "",
-                    "final class InvalidTestClassName implements RefasterRuleCollectionTestCase {}"))
-        .cause()
-        .isInstanceOf(VerifyException.class)
-        .hasMessage(
-            "Refaster rule collection test class name 'InvalidTestClassName' does not match '(.*)Test'");
-  }
-
-  @Test
-  void invalidFileName(@TempDir Path outputDirectory) {
-    assertThatThrownBy(
-            () ->
-                Compilation.compileWithDocumentationGenerator(
-                    outputDirectory,
-                    "InvalidFileNameTest.java",
-                    "import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;",
-                    "",
-                    "final class InvalidFileNameTest implements RefasterRuleCollectionTestCase {}"))
-        .cause()
-        .isInstanceOf(VerifyException.class)
-        .hasMessage(
-            "Refaster rule collection test file name '/InvalidFileNameTest.java' does not match '.*(Input|Output)\\.java'");
-  }
-
-  @Test
-  void emptyRefasterRuleCollectionTestInput(@TempDir Path outputDirectory) {
-    Compilation.compileWithDocumentationGenerator(
-        outputDirectory,
-        "EmptyRefasterRuleCollectionTestInput.java",
-        "import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;",
-        "",
-        "final class EmptyRefasterRuleCollectionTest implements RefasterRuleCollectionTestCase {}");
-
-    verifyGeneratedFileContent(
-        outputDirectory,
-        "EmptyRefasterRuleCollectionTestInput",
-        RefasterTestCases.create(
-            URI.create("file:///EmptyRefasterRuleCollectionTestInput.java"),
-            "EmptyRefasterRuleCollection",
-            /* isInput= */ true,
-            ImmutableList.of()));
-  }
-
-  @Test
-  void singletonRefasterRuleCollectionTestOutput(@TempDir Path outputDirectory) {
-    Compilation.compileWithDocumentationGenerator(
-        outputDirectory,
-        "SingletonRefasterRuleCollectionTestOutput.java",
-        "import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;",
-        "",
-        "final class SingletonRefasterRuleCollectionTest implements RefasterRuleCollectionTestCase {",
-        "  int testMyRule() {",
-        "    return 42;",
-        "  }",
-        "}");
-
-    verifyGeneratedFileContent(
-        outputDirectory,
-        "SingletonRefasterRuleCollectionTestOutput",
-        RefasterTestCases.create(
-            URI.create("file:///SingletonRefasterRuleCollectionTestOutput.java"),
-            "SingletonRefasterRuleCollection",
-            /* isInput= */ false,
-            ImmutableList.of(
-                RefasterTestCase.create(
-                    "MyRule",
-                    """
-                    int testMyRule() {
-                      return 42;
-                    }"""))));
-  }
-
-  @Test
-  void complexRefasterRuleCollectionTestOutput(@TempDir Path outputDirectory) {
-    Compilation.compileWithDocumentationGenerator(
-        outputDirectory,
-        "pkg/ComplexRefasterRuleCollectionTestInput.java",
-        "package pkg;",
-        "",
-        "import com.google.common.collect.ImmutableSet;",
-        "import tech.picnic.errorprone.refaster.test.RefasterRuleCollectionTestCase;",
-        "",
-        "final class ComplexRefasterRuleCollectionTest implements RefasterRuleCollectionTestCase {",
-        "  private static final String IGNORED_CONSTANT = \"constant\";",
-        "",
-        "  @Override",
-        "  public ImmutableSet<Object> elidedTypesAndStaticImports() {",
-        "    return ImmutableSet.of();",
-        "  }",
-        "",
-        "  /** Javadoc. */",
-        "  String testFirstRule() {",
-        "    return \"Don't panic\";",
-        "  }",
-        "",
-        "  // Comment.",
-        "  String testSecondRule() {",
-        "    return \"Carry a towel\";",
-        "  }",
-        "",
-        "  void testEmptyRule() {}",
-        "}");
-
-    verifyGeneratedFileContent(
-        outputDirectory,
-        "ComplexRefasterRuleCollectionTestInput",
-        RefasterTestCases.create(
-            URI.create("file:///pkg/ComplexRefasterRuleCollectionTestInput.java"),
-            "ComplexRefasterRuleCollection",
-            /* isInput= */ true,
-            ImmutableList.of(
-                RefasterTestCase.create(
-                    "FirstRule",
-                    """
-                    String testFirstRule() {
-                      return "Don't panic";
-                    }"""),
-                RefasterTestCase.create(
-                    "SecondRule",
-                    """
-                    String testSecondRule() {
-                      return "Carry a towel";
-                    }"""),
-                RefasterTestCase.create("EmptyRule", "void testEmptyRule() {}"))));
-  }
-
-  private static void verifyGeneratedFileContent(
-      Path outputDirectory, String testIdentifier, RefasterTestCases expected) {
-    assertThat(
-            outputDirectory.resolve(
-                String.format("refaster-rule-collection-test-%s.json", testIdentifier)))
-        .exists()
-        .returns(expected, path -> Json.read(path, RefasterTestCases.class));
-  }
-}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternExtractorTest-bugpattern-CompleteBugChecker.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternExtractorTest-bugpattern-CompleteBugChecker.json
@@ -0,0 +1,19 @@
+{
+  "fullyQualifiedName": "pkg.CompleteBugChecker",
+  "name": "OtherName",
+  "altNames": [
+    "Check"
+  ],
+  "link": "https://error-prone.picnic.tech",
+  "tags": [
+    "Simplification"
+  ],
+  "summary": "CompleteBugChecker summary",
+  "explanation": "Example explanation",
+  "severityLevel": "SUGGESTION",
+  "canDisable": false,
+  "suppressionAnnotations": [
+    "com.google.errorprone.BugPattern",
+    "org.junit.jupiter.api.Test"
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternExtractorTest-bugpattern-MinimalBugChecker.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternExtractorTest-bugpattern-MinimalBugChecker.json
@@ -0,0 +1,14 @@
+{
+  "fullyQualifiedName": "pkg.MinimalBugChecker",
+  "name": "MinimalBugChecker",
+  "altNames": [],
+  "link": "",
+  "tags": [],
+  "summary": "MinimalBugChecker summary",
+  "explanation": "",
+  "severityLevel": "ERROR",
+  "canDisable": true,
+  "suppressionAnnotations": [
+    "java.lang.SuppressWarnings"
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternExtractorTest-bugpattern-UndocumentedSuppressionBugPattern.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternExtractorTest-bugpattern-UndocumentedSuppressionBugPattern.json
@@ -0,0 +1,12 @@
+{
+  "fullyQualifiedName": "pkg.UndocumentedSuppressionBugPattern",
+  "name": "UndocumentedSuppressionBugPattern",
+  "altNames": [],
+  "link": "",
+  "tags": [],
+  "summary": "UndocumentedSuppressionBugPattern summary",
+  "explanation": "",
+  "severityLevel": "WARNING",
+  "canDisable": true,
+  "suppressionAnnotations": []
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-CompilationAndBugCheckerRefactoringTestHelpersTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-CompilationAndBugCheckerRefactoringTestHelpersTest.json
@@ -0,0 +1,24 @@
+{
+  "testClass": "CompilationAndBugCheckerRefactoringTestHelpersTest",
+  "testCases": [
+    {
+      "classUnderTest": "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "code": "// BUG: Diagnostic contains:\nclass A {}\n"
+        }
+      ]
+    },
+    {
+      "classUnderTest": "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "input": "class A {}\n",
+          "output": "class A { /* This is a change. */ }\n"
+        }
+      ]
+    }
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.json
@@ -0,0 +1,24 @@
+{
+  "testClass": "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest",
+  "testCases": [
+    {
+      "classUnderTest": "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "code": "// BUG: Diagnostic contains:\nclass A {}\n"
+        }
+      ]
+    },
+    {
+      "classUnderTest": "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker2",
+      "entries": [
+        {
+          "path": "A.java",
+          "input": "class A {}\n",
+          "output": "class A { /* This is a change. */ }\n"
+        }
+      ]
+    }
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-MultiFileBugCheckerRefactoringTestHelperTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-MultiFileBugCheckerRefactoringTestHelperTest.json
@@ -0,0 +1,20 @@
+{
+  "testClass": "MultiFileBugCheckerRefactoringTestHelperTest",
+  "testCases": [
+    {
+      "classUnderTest": "MultiFileBugCheckerRefactoringTestHelperTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "input": "class A {}\n",
+          "output": "class A { /* This is a change. */ }\n"
+        },
+        {
+          "path": "B.java",
+          "input": "class B {}\n",
+          "output": "class B { /* This is a change. */ }\n"
+        }
+      ]
+    }
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-MultiFileCompilationTestHelperTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-MultiFileCompilationTestHelperTest.json
@@ -0,0 +1,18 @@
+{
+  "testClass": "MultiFileCompilationTestHelperTest",
+  "testCases": [
+    {
+      "classUnderTest": "MultiFileCompilationTestHelperTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "code": "// BUG: Diagnostic contains:\nclass A {}\n"
+        },
+        {
+          "path": "B.java",
+          "code": "// BUG: Diagnostic contains:\nclass B {}\n"
+        }
+      ]
+    }
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileBugCheckerRefactoringTestHelperTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileBugCheckerRefactoringTestHelperTest.json
@@ -0,0 +1,15 @@
+{
+  "testClass": "SingleFileBugCheckerRefactoringTestHelperTest",
+  "testCases": [
+    {
+      "classUnderTest": "SingleFileBugCheckerRefactoringTestHelperTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "input": "class A {}\n",
+          "output": "class A { /* This is a change. */ }\n"
+        }
+      ]
+    }
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.json
@@ -0,0 +1,15 @@
+{
+  "testClass": "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest",
+  "testCases": [
+    {
+      "classUnderTest": "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "input": "class A {}\n",
+          "output": "class A { /* This is a change. */ }\n"
+        }
+      ]
+    }
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileCompilationTestHelperTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileCompilationTestHelperTest.json
@@ -0,0 +1,14 @@
+{
+  "testClass": "SingleFileCompilationTestHelperTest",
+  "testCases": [
+    {
+      "classUnderTest": "SingleFileCompilationTestHelperTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "code": "// BUG: Diagnostic contains:\nclass A {}\n"
+        }
+      ]
+    }
+  ]
+}
--- a/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileCompilationTestHelperWithSetArgsTest.json
+++ b/documentation-support/src/test/resources/tech/picnic/errorprone/documentation/BugPatternTestExtractorTest-bugpattern-test-SingleFileCompilationTestHelperWithSetArgsTest.json
@@ -0,0 +1,14 @@
+{
+  "testClass": "SingleFileCompilationTestHelperWithSetArgsTest",
+  "testCases": [
+    {
+      "classUnderTest": "SingleFileCompilationTestHelperWithSetArgsTest.TestChecker",
+      "entries": [
+        {
+          "path": "A.java",
+          "code": "// BUG: Diagnostic contains:\nclass A {}\n"
+        }
+      ]
+    }
+  ]
+}
--- a/error-prone-contrib/pom.xml
+++ b/error-prone-contrib/pom.xml
@@ -5,16 +5,40 @@
    <parent>
        <groupId>tech.picnic.error-prone-support</groupId>
        <artifactId>error-prone-support</artifactId>
-        <version>0.20.0</version>
+        <version>0.14.1-SNAPSHOT</version>
    </parent>

    <artifactId>error-prone-contrib</artifactId>

    <name>Picnic :: Error Prone Support :: Contrib</name>
    <description>Extra Error Prone plugins by Picnic.</description>
-    <url>https://error-prone.picnic.tech</url>

    <dependencies>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_annotation</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_annotations</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_check_api</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_core</artifactId>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>${groupId.error-prone}</groupId>
+            <artifactId>error_prone_test_helpers</artifactId>
+            <scope>provided</scope>
+        </dependency>
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>documentation-support</artifactId>
@@ -23,19 +47,10 @@
            `annotationProcessorPaths` configuration below. -->
            <scope>provided</scope>
        </dependency>
-        <dependency>
-            <groupId>${project.groupId}</groupId>
-            <artifactId>error-prone-utils</artifactId>
-        </dependency>
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>refaster-support</artifactId>
-            <!-- XXX: One would expect this to be a `provided` dependency (as
-            Refaster rules are interpreted by the `refaster-runner` module),
-            but the `OptionalOrElseGet` bug checker defined by this module
-            depends on the `RequiresComputation` matcher that
-            `refaster-support` primarily exposes for use by Refaster rules.
-            Review this setup. (Should the matchers be moved elsewhere?) -->
+            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>${project.groupId}</groupId>
@@ -45,11 +60,11 @@
        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-annotations</artifactId>
-            <scope>provided</scope>
+            <scope>test</scope>
        </dependency>
        <dependency>
-            <groupId>com.github.ben-manes.caffeine</groupId>
-            <artifactId>caffeine</artifactId>
+            <groupId>com.google.auto</groupId>
+            <artifactId>auto-common</artifactId>
            <scope>provided</scope>
        </dependency>
        <dependency>
@@ -63,40 +78,14 @@
            <scope>provided</scope>
        </dependency>
        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_annotation</artifactId>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_annotations</artifactId>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_check_api</artifactId>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_core</artifactId>
-            <scope>provided</scope>
-        </dependency>
-        <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>error_prone_test_helpers</artifactId>
-            <scope>provided</scope>
+            <groupId>com.google.googlejavaformat</groupId>
+            <artifactId>google-java-format</artifactId>
        </dependency>
        <dependency>
            <groupId>com.google.guava</groupId>
            <artifactId>guava</artifactId>
            <scope>provided</scope>
        </dependency>
-        <dependency>
-            <groupId>io.micrometer</groupId>
-            <artifactId>micrometer-core</artifactId>
-            <scope>provided</scope>
-        </dependency>
        <dependency>
            <groupId>io.projectreactor</groupId>
            <artifactId>reactor-core</artifactId>
@@ -137,11 +126,6 @@
            <artifactId>jakarta.servlet-api</artifactId>
            <scope>test</scope>
        </dependency>
-        <dependency>
-            <groupId>javax.annotation</groupId>
-            <artifactId>javax.annotation-api</artifactId>
-            <scope>provided</scope>
-        </dependency>
        <dependency>
            <groupId>javax.inject</groupId>
            <artifactId>javax.inject</artifactId>
@@ -163,13 +147,12 @@
            <scope>provided</scope>
        </dependency>
        <dependency>
-            <groupId>org.immutables</groupId>
-            <artifactId>value-annotations</artifactId>
-            <scope>test</scope>
+            <groupId>org.checkerframework</groupId>
+            <artifactId>checker-util</artifactId>
        </dependency>
        <dependency>
-            <groupId>org.jooq</groupId>
-            <artifactId>jooq</artifactId>
+            <groupId>org.immutables</groupId>
+            <artifactId>value-annotations</artifactId>
            <scope>test</scope>
        </dependency>
        <dependency>
@@ -182,8 +165,6 @@
            <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>
@@ -204,31 +185,6 @@
            <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-17</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>
@@ -264,11 +220,6 @@
            <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>
@@ -284,9 +235,6 @@
                    <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>
@@ -304,58 +252,10 @@
                            </path>
                        </annotationProcessorPaths>
                        <compilerArgs combine.children="append">
+                            <arg>-Xplugin:RefasterRuleCompiler</arg>
                            <arg>-Xplugin:DocumentationGenerator -XoutputDirectory=${project.build.directory}/docs</arg>
                        </compilerArgs>
                    </configuration>
-                    <executions>
-                        <!-- The Refaster input/output test classes used by
-                        `RefasterRuleCollection` are modelled as classpath
-                        resources, and thus not subject to the default test
-                        compilation step. These two custom compilation steps
-                        serve two purposes:
-                        - To provide early feedback in case of syntax errors.
-                        - To enable the `DocumentationGenerator` compiler
-                        plugin to extract documentation metadata from them.
-                        Note that the input and output files must be compiled
-                        separately and to distinct output directories, as they
-                        define the same set of class names. -->
-                        <!-- XXX: Drop these executions if/when the Refaster
-                        test framework is reimplemented such that tests can be
-                        located alongside rules, rather than in two additional
-                        resource files. -->
-                        <execution>
-                            <id>compile-refaster-test-input</id>
-                            <goals>
-                                <goal>testCompile</goal>
-                            </goals>
-                            <phase>process-test-resources</phase>
-                            <configuration>
-                                <compileSourceRoots>
-                                    <compileSourceRoot>${project.basedir}/src/test/resources</compileSourceRoot>
-                                </compileSourceRoots>
-                                <testIncludes>
-                                    <testInclude>**/*Input.java</testInclude>
-                                </testIncludes>
-                                <outputDirectory>${project.build.directory}/refaster-test-input</outputDirectory>
-                            </configuration>
-                        </execution>
-                        <execution>
-                            <id>compile-refaster-test-output</id>
-                            <goals>
-                                <goal>testCompile</goal>
-                            </goals>
-                            <phase>process-test-resources</phase>
-                            <configuration>
-                                <compileSourceRoots>
-                                    <compileSourceRoot>${project.basedir}/src/test/resources</compileSourceRoot>
-                                </compileSourceRoots>
-                                <testIncludes>
-                                    <testInclude>**/*Output.java</testInclude>
-                                </testIncludes>
-                                <outputDirectory>${project.build.directory}/refaster-test-output</outputDirectory>
-                            </configuration>
-                        </execution>
-                    </executions>
                </plugin>
            </plugins>
        </pluginManagement>
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/AmbiguousJsonCreator.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -18,7 +18,7 @@ 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.Kind;
+import com.sun.source.tree.Tree;
 import com.sun.tools.javac.code.Symbol;
 import java.util.Map;
 import javax.lang.model.element.AnnotationValue;
@@ -46,7 +46,7 @@ public final class AmbiguousJsonCreator extends BugChecker implements Annotation
    }

    ClassTree clazz = state.findEnclosing(ClassTree.class);
-    if (clazz == null || clazz.getKind() != Kind.ENUM) {
+    if (clazz == null || clazz.getKind() != Tree.Kind.ENUM) {
      return Description.NO_MATCH;
    }

--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/AssertJIsNull.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
--- a/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/AssociativeMethodInvocation.java
+++ b/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/AssociativeMethodInvocation.java
@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.guidelines.bugpatterns;
+package tech.picnic.errorprone.bugpatterns;

 import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
 import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
@@ -7,7 +7,7 @@ import static com.google.errorprone.matchers.Matchers.allOf;
 import static com.google.errorprone.matchers.Matchers.not;
 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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -27,7 +27,7 @@ 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 tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags unnecessarily nested usage of methods that implement an
@@ -36,8 +36,6 @@ import tech.picnic.errorprone.utils.SourceCode;
 * <p>The arguments to such methods can be flattened without affecting semantics, while making the
 * code more readable.
 */
-// XXX: Move this check to the `error-prone-contrib` module once it also covers non-Error Prone
-// methods.
@AutoService(BugChecker.class)
@BugPattern(
    summary =
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/AutowiredConstructor.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/AutowiredConstructor.java
@@ -6,7 +6,7 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
@@ -23,7 +23,7 @@ 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.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /** A {@link BugChecker} that flags redundant {@code @Autowired} constructor annotations. */
@AutoService(BugChecker.class)
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/CanonicalAnnotationSyntax.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -19,13 +19,14 @@ import com.sun.source.tree.AnnotationTree;
 import com.sun.source.tree.AssignmentTree;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.NewArrayTree;
+import com.sun.source.tree.Tree.Kind;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /** A {@link BugChecker} that flags annotations that could be written more concisely. */
@AutoService(BugChecker.class)
@@ -118,7 +119,7 @@ public final class CanonicalAnnotationSyntax extends BugChecker implements Annot
       * the expression as a whole.
       */
      ExpressionTree value =
-          (arg instanceof AssignmentTree assignment) ? assignment.getExpression() : arg;
+          (arg.getKind() == Kind.ASSIGNMENT) ? ((AssignmentTree) arg).getExpression() : arg;

      /* Store a fix for each expression that was successfully simplified. */
      simplifyAttributeValue(value, state)
@@ -129,10 +130,13 @@ public final class CanonicalAnnotationSyntax extends BugChecker implements Annot
  }

  private static Optional<String> simplifyAttributeValue(ExpressionTree expr, VisitorState state) {
-    /* Drop curly braces or commas if possible. */
-    return expr instanceof NewArrayTree newArray
-        ? simplifySingletonArray(newArray, state).or(() -> dropTrailingComma(newArray, state))
-        : Optional.empty();
+    if (expr.getKind() != Kind.NEW_ARRAY) {
+      /* There are no curly braces or commas to be dropped here. */
+      return Optional.empty();
+    }
+
+    NewArrayTree array = (NewArrayTree) expr;
+    return simplifySingletonArray(array, state).or(() -> dropTrailingComma(array, state));
  }

  /** Returns the expression describing the array's sole element, if any. */
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/CanonicalClassNameUsage.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/CanonicalClassNameUsage.java
@@ -9,7 +9,7 @@ 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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -81,8 +81,9 @@ public final class CanonicalClassNameUsage extends BugChecker
      path = path.getParentPath();
    }

-    return path.getLeaf() instanceof MethodInvocationTree methodInvocation
-        && isOwnedByCanonicalNameUsingType(ASTHelpers.getSymbol(methodInvocation));
+    return path.getLeaf() instanceof MethodInvocationTree
+        && isOwnedByCanonicalNameUsingType(
+            ASTHelpers.getSymbol((MethodInvocationTree) path.getLeaf()));
  }

  private static boolean isOwnedByCanonicalNameUsingType(MethodSymbol symbol) {
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ClassCastLambdaUsage.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ClassCastLambdaUsage.java
@@ -1,76 +0,0 @@
-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.utils.Documentation.BUG_PATTERNS_BASE_URL;
-
-import com.google.auto.service.AutoService;
-import com.google.common.collect.Iterables;
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.bugpatterns.BugChecker;
-import com.google.errorprone.bugpatterns.BugChecker.LambdaExpressionTreeMatcher;
-import com.google.errorprone.fixes.SuggestedFix;
-import com.google.errorprone.matchers.Description;
-import com.google.errorprone.util.ASTHelpers;
-import com.sun.source.tree.LambdaExpressionTree;
-import com.sun.source.tree.TypeCastTree;
-import com.sun.source.tree.VariableTree;
-import com.sun.tools.javac.code.Type;
-import javax.lang.model.type.TypeKind;
-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::cast}.
- */
-// XXX: Consider folding this logic into the `MethodReferenceUsage` check of the
-// `error-prone-experimental` module.
-// XXX: This check and its tests are structurally nearly identical to `IsInstanceLambdaUsage`.
-// Unless folded into `MethodReferenceUsage`, consider merging the two.
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "Prefer `Class::cast` method reference over equivalent lambda expression",
-    link = BUG_PATTERNS_BASE_URL + "ClassCastLambdaUsage",
-    linkType = CUSTOM,
-    severity = SUGGESTION,
-    tags = SIMPLIFICATION)
-public final class ClassCastLambdaUsage extends BugChecker implements LambdaExpressionTreeMatcher {
-  private static final long serialVersionUID = 1L;
-
-  /** Instantiates a new {@link ClassCastLambdaUsage} instance. */
-  public ClassCastLambdaUsage() {}
-
-  @Override
-  public Description matchLambdaExpression(LambdaExpressionTree tree, VisitorState state) {
-    if (tree.getParameters().size() != 1 || !(tree.getBody() instanceof TypeCastTree typeCast)) {
-      return Description.NO_MATCH;
-    }
-
-    Type type = ASTHelpers.getType(typeCast);
-    if (type == null
-        || type.isParameterized()
-        || type.isPrimitive()
-        || type.getKind() == TypeKind.TYPEVAR) {
-      /*
-       * The method reference syntax does not support casting to parameterized types, and type
-       * variables aren't supported either. Additionally, `Class#cast` does not support the same
-       * range of type conversions between (boxed) primitive types as the cast operator.
-       */
-      // XXX: Depending on the declared type of the value being cast, in some cases we _can_ rewrite
-      // primitive casts. Add support for this.
-      return Description.NO_MATCH;
-    }
-
-    VariableTree param = Iterables.getOnlyElement(tree.getParameters());
-    if (!ASTHelpers.getSymbol(param).equals(ASTHelpers.getSymbol(typeCast.getExpression()))) {
-      return Description.NO_MATCH;
-    }
-
-    return describeMatch(
-        tree,
-        SuggestedFix.replace(
-            tree, SourceCode.treeToString(typeCast.getType(), state) + ".class::cast"));
-  }
-}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/CollectorMutability.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/CollectorMutability.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.FRAGILE_CODE;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableList;
@@ -25,7 +25,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.stream.Collector;
 import java.util.stream.Collectors;
-import tech.picnic.errorprone.utils.ThirdPartyLibrary;
+import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;

 /**
 * A {@link BugChecker} that flags {@link Collector Collectors} that don't clearly express
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ConstantNaming.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ConstantNaming.java
@@ -1,125 +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.STYLE;
-import static com.google.errorprone.matchers.Matchers.allOf;
-import static com.google.errorprone.matchers.Matchers.hasModifier;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
-
-import com.google.auto.service.AutoService;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Sets;
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.ErrorProneFlags;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.bugpatterns.BugChecker;
-import com.google.errorprone.bugpatterns.BugChecker.VariableTreeMatcher;
-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.VariableTree;
-import com.sun.source.util.TreeScanner;
-import java.util.Locale;
-import java.util.regex.Pattern;
-import javax.inject.Inject;
-import javax.lang.model.element.Modifier;
-import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.utils.Flags;
-
-/**
- * A {@link BugChecker} that flags static constants that do not follow the upper snake case naming
- * convention.
- */
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "Constant variables should adhere to the `UPPER_SNAKE_CASE` naming convention",
-    link = BUG_PATTERNS_BASE_URL + "ConstantNaming",
-    linkType = CUSTOM,
-    severity = WARNING,
-    tags = STYLE)
-@SuppressWarnings("java:S2160" /* Super class equality definition suffices. */)
-public final class ConstantNaming extends BugChecker implements VariableTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Matcher<VariableTree> IS_CONSTANT =
-      allOf(hasModifier(Modifier.STATIC), hasModifier(Modifier.FINAL));
-  private static final Matcher<VariableTree> IS_PRIVATE = hasModifier(Modifier.PRIVATE);
-  private static final Pattern SNAKE_CASE = Pattern.compile("([a-z])([A-Z])");
-  private static final ImmutableSet<String> DEFAULT_EXEMPTED_NAMES =
-      ImmutableSet.of("serialVersionUID");
-
-  /**
-   * Flag using which constant names that must not be flagged (in addition to those defined by
-   * {@link #DEFAULT_EXEMPTED_NAMES}) can be specified.
-   */
-  private static final String ADDITIONAL_EXEMPTED_NAMES_FLAG =
-      "CanonicalConstantNaming:ExemptedNames";
-
-  private final ImmutableSet<String> exemptedNames;
-
-  /** Instantiates a default {@link ConstantNaming} instance. */
-  public ConstantNaming() {
-    this(ErrorProneFlags.empty());
-  }
-
-  /**
-   * Instantiates a customized {@link ConstantNaming}.
-   *
-   * @param flags Any provided command line flags.
-   */
-  @Inject
-  ConstantNaming(ErrorProneFlags flags) {
-    exemptedNames =
-        Sets.union(DEFAULT_EXEMPTED_NAMES, Flags.getSet(flags, ADDITIONAL_EXEMPTED_NAMES_FLAG))
-            .immutableCopy();
-  }
-
-  @Override
-  public Description matchVariable(VariableTree tree, VisitorState state) {
-    String variableName = tree.getName().toString();
-    if (!IS_CONSTANT.matches(tree, state) || exemptedNames.contains(variableName)) {
-      return Description.NO_MATCH;
-    }
-
-    String replacement = toUpperSnakeCase(variableName);
-    if (replacement.equals(variableName)) {
-      return Description.NO_MATCH;
-    }
-
-    Description.Builder description = buildDescription(tree);
-    if (!IS_PRIVATE.matches(tree, state)) {
-      description.setMessage(
-          "%s; consider renaming to '%s', though note that this is not a private constant"
-              .formatted(message(), replacement));
-    } else if (isVariableNameInUse(replacement, state)) {
-      description.setMessage(
-          "%s; consider renaming to '%s', though note that a variable with this name is already declared"
-              .formatted(message(), replacement));
-    } else {
-      description.addFix(SuggestedFixes.renameVariable(tree, replacement, state));
-    }
-
-    return description.build();
-  }
-
-  private static String toUpperSnakeCase(String variableName) {
-    return SNAKE_CASE.matcher(variableName).replaceAll("$1_$2").toUpperCase(Locale.ROOT);
-  }
-
-  private static boolean isVariableNameInUse(String name, VisitorState state) {
-    return Boolean.TRUE.equals(
-        new TreeScanner<Boolean, @Nullable Void>() {
-          @Override
-          public Boolean visitVariable(VariableTree tree, @Nullable Void unused) {
-            return ASTHelpers.getSymbol(tree).getSimpleName().contentEquals(name)
-                || super.visitVariable(tree, null);
-          }
-
-          @Override
-          public Boolean reduce(Boolean r1, Boolean r2) {
-            return Boolean.TRUE.equals(r1) || Boolean.TRUE.equals(r2);
-          }
-        }.scan(state.getPath().getCompilationUnit(), null));
-  }
-}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/DirectReturn.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/DirectReturn.java
@@ -11,7 +11,7 @@ import static com.google.errorprone.matchers.Matchers.not;
 import static com.google.errorprone.matchers.Matchers.returnStatement;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
 import static com.google.errorprone.matchers.Matchers.toType;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.Streams;
@@ -39,8 +39,8 @@ import com.sun.tools.javac.code.Symbol;
 import java.util.List;
 import java.util.Optional;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.utils.MoreASTHelpers;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.MoreASTHelpers;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags unnecessary local variable assignments preceding a return
@@ -101,17 +101,19 @@ public final class DirectReturn extends BugChecker implements BlockTreeMatcher {
  }

  private static Optional<ExpressionTree> tryMatchAssignment(Symbol targetSymbol, Tree tree) {
-    if (tree instanceof ExpressionStatementTree expressionStatement) {
-      return tryMatchAssignment(targetSymbol, expressionStatement.getExpression());
+    if (tree instanceof ExpressionStatementTree) {
+      return tryMatchAssignment(targetSymbol, ((ExpressionStatementTree) tree).getExpression());
    }

-    if (tree instanceof AssignmentTree assignment) {
+    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 declaration) {
+    if (tree instanceof VariableTree) {
+      VariableTree declaration = (VariableTree) tree;
      return declaration.getModifiers().getAnnotations().isEmpty()
              && targetSymbol.equals(ASTHelpers.getSymbol(declaration))
          ? Optional.ofNullable(declaration.getInitializer())
@@ -149,11 +151,11 @@ public final class DirectReturn extends BugChecker implements BlockTreeMatcher {
            Streams.stream(state.getPath()).skip(1),
            Streams.stream(state.getPath()),
            (tree, child) -> {
-              if (!(tree instanceof TryTree tryTree)) {
+              if (!(tree instanceof TryTree)) {
                return null;
              }

-              BlockTree finallyBlock = tryTree.getFinallyBlock();
+              BlockTree finallyBlock = ((TryTree) tree).getFinallyBlock();
              return !child.equals(finallyBlock) ? finallyBlock : null;
            })
        .anyMatch(finallyBlock -> referencesIdentifierSymbol(symbol, finallyBlock));
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/EagerStringFormatting.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/EagerStringFormatting.java
@@ -1,325 +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.PERFORMANCE;
-import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
-import static com.google.errorprone.matchers.Matchers.anyOf;
-import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
-import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
-import static java.util.Objects.requireNonNull;
-import static java.util.stream.Collectors.joining;
-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.base.Preconditions;
-import com.google.common.base.Verify;
-import com.google.common.base.VerifyException;
-import com.google.common.collect.ImmutableList;
-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.SuggestedFix;
-import com.google.errorprone.matchers.Description;
-import com.google.errorprone.matchers.Matcher;
-import com.google.errorprone.util.ASTHelpers;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.MethodInvocationTree;
-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.Symbol.VarSymbol;
-import java.util.Collections;
-import java.util.Formattable;
-import java.util.List;
-import java.util.Locale;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.stream.Stream;
-import tech.picnic.errorprone.utils.SourceCode;
-
-/**
- * A {@link BugChecker} that flags {@link String#format} and {@link String#formatted} invocations
- * that can be omitted by delegating to another format method.
- */
-// XXX: The special-casing of Throwable applies only to SLF4J 1.6.0+; see
-// https://www.slf4j.org/faq.html#paramException. That should be documented.
-// XXX: Some of the `Matcher`s defined here are also declared by the `Slf4jLogStatement` and
-// `RedundantStringConversion` checks. Look into deduplicating them.
-// XXX: Should we also simplify e.g. `LOG.error(String.join("sep", arg1, arg2), throwable)`? Perhaps
-// that's too obscure.
-// XXX: This check currently only flags string format expressions that are a direct argument to
-// another format-capable method invocation. Indirect cases, such as where the result is assigned to
-// a variable, are currently not covered.
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "String formatting can be deferred",
-    link = BUG_PATTERNS_BASE_URL + "EagerStringFormatting",
-    linkType = CUSTOM,
-    severity = WARNING,
-    tags = {PERFORMANCE, SIMPLIFICATION})
-public final class EagerStringFormatting extends BugChecker implements MethodInvocationTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Matcher<ExpressionTree> FORMATTABLE = isSubtypeOf(Formattable.class);
-  private static final Matcher<ExpressionTree> LOCALE = isSubtypeOf(Locale.class);
-  private static final Matcher<ExpressionTree> SLF4J_MARKER = isSubtypeOf("org.slf4j.Marker");
-  private static final Matcher<ExpressionTree> THROWABLE = isSubtypeOf(Throwable.class);
-  private static final Matcher<ExpressionTree> REQUIRE_NON_NULL_INVOCATION =
-      staticMethod().onClass(Objects.class.getCanonicalName()).named("requireNonNull");
-  private static final Matcher<ExpressionTree> GUAVA_GUARD_INVOCATION =
-      anyOf(
-          staticMethod()
-              .onClass(Preconditions.class.getCanonicalName())
-              .namedAnyOf("checkArgument", "checkNotNull", "checkState"),
-          staticMethod()
-              .onClass(Verify.class.getCanonicalName())
-              .namedAnyOf("verify", "verifyNotNull"));
-  private static final Matcher<ExpressionTree> SLF4J_LOGGER_INVOCATION =
-      instanceMethod()
-          .onDescendantOf("org.slf4j.Logger")
-          .namedAnyOf("trace", "debug", "info", "warn", "error");
-  private static final Matcher<ExpressionTree> STATIC_FORMAT_STRING =
-      staticMethod().onClass(String.class.getCanonicalName()).named("format");
-  private static final Matcher<ExpressionTree> INSTANCE_FORMAT_STRING =
-      instanceMethod().onDescendantOf(String.class.getCanonicalName()).named("formatted");
-  private static final String MESSAGE_NEVER_NULL_ARGUMENT =
-      "String formatting never yields `null` expression";
-
-  /** Instantiates a new {@link EagerStringFormatting} instance. */
-  public EagerStringFormatting() {}
-
-  @Override
-  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    Tree parent = state.getPath().getParentPath().getLeaf();
-    if (!(parent instanceof MethodInvocationTree methodInvocation)) {
-      /*
-       * Fast path: this isn't a method invocation whose result is an argument to another method
-       * invocation.
-       */
-      // XXX: This logic assumes that the string format operation isn't redundantly wrapped in
-      // parentheses. Similar assumptions likely exist throughout the code base. Investigate how to
-      // structurally cover such cases.
-      return Description.NO_MATCH;
-    }
-
-    return StringFormatExpression.tryCreate(tree, state)
-        .map(expr -> analyzeFormatStringContext(expr, methodInvocation, state))
-        .orElse(Description.NO_MATCH);
-  }
-
-  private Description analyzeFormatStringContext(
-      StringFormatExpression stringFormat, MethodInvocationTree context, VisitorState state) {
-    if (REQUIRE_NON_NULL_INVOCATION.matches(context, state)) {
-      return analyzeRequireNonNullStringFormatContext(stringFormat, context);
-    }
-
-    if (GUAVA_GUARD_INVOCATION.matches(context, state)) {
-      return analyzeGuavaGuardStringFormatContext(stringFormat, context, state);
-    }
-
-    if (SLF4J_LOGGER_INVOCATION.matches(context, state)) {
-      return analyzeSlf4jLoggerStringFormatContext(stringFormat, context, state);
-    }
-
-    /*
-     * The string formatting operation does not appear to happen in a context that admits of
-     * simplification or optimization.
-     */
-    return Description.NO_MATCH;
-  }
-
-  private Description analyzeRequireNonNullStringFormatContext(
-      StringFormatExpression stringFormat, MethodInvocationTree context) {
-    List<? extends ExpressionTree> arguments = context.getArguments();
-    if (arguments.size() != 2 || arguments.get(0).equals(stringFormat.expression())) {
-      /* Vacuous validation that string formatting doesn't yield `null`. */
-      return buildDescription(context).setMessage(MESSAGE_NEVER_NULL_ARGUMENT).build();
-    }
-
-    if (stringFormat.arguments().stream()
-        .anyMatch(EagerStringFormatting::isNonFinalLocalVariable)) {
-      /*
-       * The format operation depends on a variable that isn't final or effectively final; moving
-       * it into a lambda expression would cause a compilation error.
-       */
-      return buildDescription(context)
-          .setMessage(message() + " (but this requires introducing an effectively final variable)")
-          .build();
-    }
-
-    /* Suggest that the string formatting is deferred. */
-    return describeMatch(context, SuggestedFix.prefixWith(stringFormat.expression(), "() -> "));
-  }
-
-  private Description analyzeGuavaGuardStringFormatContext(
-      StringFormatExpression stringFormat, MethodInvocationTree context, VisitorState state) {
-    List<? extends ExpressionTree> arguments = context.getArguments();
-    if (arguments.get(0).equals(stringFormat.expression())) {
-      /*
-       * Vacuous `checkNotNull` or `verifyNotNull` validation that string formatting doesn't yield
-       * `null`.
-       */
-      return buildDescription(context).setMessage(MESSAGE_NEVER_NULL_ARGUMENT).build();
-    }
-
-    if (stringFormat.simplifiableFormatString().isEmpty() || arguments.size() > 2) {
-      /*
-       * The format string cannot be simplified, or the format string produces a format string
-       * itself, or its result is the input to another format operation. These are complex cases
-       * that we'll only flag.
-       */
-      return createSimplificationSuggestion(context, "Guava");
-    }
-
-    return describeMatch(context, stringFormat.suggestFlattening("%s", state));
-  }
-
-  private Description analyzeSlf4jLoggerStringFormatContext(
-      StringFormatExpression stringFormat, MethodInvocationTree context, VisitorState state) {
-    if (stringFormat.simplifiableFormatString().isEmpty()) {
-      /* We can't simplify this case; only flag it. */
-      return createSimplificationSuggestion(context, "SLF4J");
-    }
-
-    List<? extends ExpressionTree> arguments = context.getArguments();
-    int leftOffset = SLF4J_MARKER.matches(arguments.get(0), state) ? 1 : 0;
-    int rightOffset = THROWABLE.matches(arguments.get(arguments.size() - 1), state) ? 1 : 0;
-    if (arguments.size() != leftOffset + 1 + rightOffset) {
-      /*
-       * The format string produces a format string itself, or its result is the input to another
-       * format operation. This is a complex case that we'll only flag.
-       */
-      return createSimplificationSuggestion(context, "SLF4J");
-    }
-
-    return describeMatch(context, stringFormat.suggestFlattening("{}", state));
-  }
-
-  private static boolean isNonFinalLocalVariable(Tree tree) {
-    Symbol symbol = ASTHelpers.getSymbol(tree);
-    return symbol instanceof VarSymbol
-        && symbol.owner instanceof MethodSymbol
-        && !ASTHelpers.isConsideredFinal(symbol);
-  }
-
-  private Description createSimplificationSuggestion(MethodInvocationTree context, String library) {
-    return buildDescription(context)
-        .setMessage(
-            "%s (assuming that %s's simplified formatting support suffices)"
-                .formatted(message(), library))
-        .build();
-  }
-
-  /** Description of a string format expression. */
-  @AutoValue
-  abstract static class StringFormatExpression {
-    /** The full string format expression. */
-    abstract MethodInvocationTree expression();
-
-    /** The format string expression. */
-    abstract Tree formatString();
-
-    /** The string format arguments to be plugged into its format string. */
-    abstract ImmutableList<ExpressionTree> arguments();
-
-    /**
-     * The constant format string, if it contains only {@code %s} placeholders, and the number of
-     * said placeholders matches the number of format arguments.
-     */
-    abstract Optional<String> simplifiableFormatString();
-
-    private SuggestedFix suggestFlattening(String newPlaceholder, VisitorState state) {
-      return SuggestedFix.replace(
-          expression(),
-          Stream.concat(
-                  Stream.of(deriveFormatStringExpression(newPlaceholder, state)),
-                  arguments().stream().map(arg -> SourceCode.treeToString(arg, state)))
-              .collect(joining(", ")));
-    }
-
-    private String deriveFormatStringExpression(String newPlaceholder, VisitorState state) {
-      String formatString =
-          String.format(
-              simplifiableFormatString()
-                  .orElseThrow(() -> new VerifyException("Format string cannot be simplified")),
-              Collections.nCopies(arguments().size(), newPlaceholder).toArray());
-
-      /*
-       * If the suggested replacement format string is the same as the original, then use the
-       * expression's existing source code representation. This way string constant references are
-       * not unnecessarily replaced.
-       */
-      return formatString.equals(ASTHelpers.constValue(formatString(), String.class))
-          ? SourceCode.treeToString(formatString(), state)
-          : SourceCode.toStringConstantExpression(formatString, state);
-    }
-
-    private static Optional<StringFormatExpression> tryCreate(
-        MethodInvocationTree tree, VisitorState state) {
-      if (INSTANCE_FORMAT_STRING.matches(tree, state)) {
-        return Optional.of(
-            create(
-                tree,
-                requireNonNull(ASTHelpers.getReceiver(tree), "Receiver unexpectedly absent"),
-                ImmutableList.copyOf(tree.getArguments()),
-                state));
-      }
-
-      if (STATIC_FORMAT_STRING.matches(tree, state)) {
-        List<? extends ExpressionTree> arguments = tree.getArguments();
-        int argOffset = LOCALE.matches(arguments.get(0), state) ? 1 : 0;
-        return Optional.of(
-            create(
-                tree,
-                arguments.get(argOffset),
-                ImmutableList.copyOf(arguments.subList(argOffset + 1, arguments.size())),
-                state));
-      }
-
-      return Optional.empty();
-    }
-
-    private static StringFormatExpression create(
-        MethodInvocationTree expression,
-        Tree formatString,
-        ImmutableList<ExpressionTree> arguments,
-        VisitorState state) {
-      return new AutoValue_EagerStringFormatting_StringFormatExpression(
-          expression,
-          formatString,
-          arguments,
-          Optional.ofNullable(ASTHelpers.constValue(formatString, String.class))
-              .filter(template -> isSimplifiable(template, arguments, state)));
-    }
-
-    private static boolean isSimplifiable(
-        String formatString, ImmutableList<ExpressionTree> arguments, VisitorState state) {
-      if (arguments.stream().anyMatch(arg -> FORMATTABLE.matches(arg, state))) {
-        /* `Formattable` arguments can have arbitrary format semantics. */
-        return false;
-      }
-
-      @Var int placeholderCount = 0;
-      for (int p = formatString.indexOf('%'); p != -1; p = formatString.indexOf('%', p + 2)) {
-        if (p == formatString.length() - 1) {
-          /* Malformed format string with trailing `%`. */
-          return false;
-        }
-
-        char modifier = formatString.charAt(p + 1);
-        if (modifier == 's') {
-          placeholderCount++;
-        } else if (modifier != '%') {
-          /* Only `%s` and `%%` (a literal `%`) are supported. */
-          return false;
-        }
-      }
-
-      return placeholderCount == arguments.size();
-    }
-  }
-}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/EmptyMethod.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.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.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /** A {@link BugChecker} that flags empty methods that seemingly can simply be deleted. */
@AutoService(BugChecker.class)
@@ -62,7 +62,7 @@ public final class EmptyMethod extends BugChecker implements MethodTreeMatcher {
  }

  private static boolean isInPossibleTestHelperClass(VisitorState state) {
-    return Optional.ofNullable(state.findEnclosing(ClassTree.class))
+    return Optional.ofNullable(ASTHelpers.findEnclosingNode(state.getPath(), ClassTree.class))
        .map(ClassTree::getSimpleName)
        .filter(name -> name.toString().contains("Test"))
        .isPresent();
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/EmptyMonoZip.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/EmptyMonoZip.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.ERROR;
-import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
-import static com.google.errorprone.matchers.Matchers.anyOf;
-import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static com.google.errorprone.matchers.Matchers.typePredicateMatcher;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
-import static tech.picnic.errorprone.utils.MoreTypePredicates.isSubTypeOf;
-import static tech.picnic.errorprone.utils.MoreTypes.generic;
-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.google.errorprone.suppliers.Suppliers;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.MemberSelectTree;
-import com.sun.source.tree.MethodInvocationTree;
-import com.sun.tools.javac.code.Type;
-import reactor.core.publisher.Mono;
-
-/**
- * A {@link BugChecker} that flags {@link Mono#zip} and {@link Mono#zipWith} invocations with a
- * {@code Mono<Void>} or {@link Mono#empty()} argument or receiver.
- *
- * <p>When a zipped reactive stream completes empty, then the other zipped streams will be cancelled
- * (or not subscribed to), and the operation as a whole will complete empty as well. This is
- * generally not what was intended.
- */
-// XXX: Generalize this check to also cover `Flux` zip operations.
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "Don't pass a `Mono<Void>` or `Mono.empty()` argument to `Mono#{zip,With}`",
-    link = BUG_PATTERNS_BASE_URL + "EmptyMonoZip",
-    linkType = CUSTOM,
-    severity = ERROR,
-    tags = LIKELY_ERROR)
-public final class EmptyMonoZip extends BugChecker implements MethodInvocationTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Supplier<Type> MONO =
-      Suppliers.typeFromString("reactor.core.publisher.Mono");
-  private static final Matcher<ExpressionTree> MONO_ZIP_OR_ZIP_WITH =
-      anyOf(
-          instanceMethod().onDescendantOf(MONO).named("zipWith"),
-          staticMethod().onClass(MONO).named("zip"));
-  private static final Matcher<ExpressionTree> EMPTY_MONO =
-      anyOf(
-          staticMethod().onDescendantOf(MONO).named("empty"),
-          typePredicateMatcher(isSubTypeOf(generic(MONO, type(Void.class.getCanonicalName())))));
-
-  /** Instantiates a new {@link EmptyMonoZip} instance. */
-  public EmptyMonoZip() {}
-
-  @Override
-  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    if (!MONO_ZIP_OR_ZIP_WITH.matches(tree, state)) {
-      return Description.NO_MATCH;
-    }
-
-    if (hasEmptyReceiver(tree, state)) {
-      return buildDescription(tree)
-          .setMessage("Invoking `Mono#zipWith` on `Mono#empty()` or a `Mono<Void>` is a no-op")
-          .build();
-    }
-
-    if (hasEmptyArguments(tree, state)) {
-      return describeMatch(tree);
-    }
-
-    return Description.NO_MATCH;
-  }
-
-  private static boolean hasEmptyReceiver(MethodInvocationTree tree, VisitorState state) {
-    return tree.getMethodSelect() instanceof MemberSelectTree memberSelect
-        && EMPTY_MONO.matches(memberSelect.getExpression(), state);
-  }
-
-  private static boolean hasEmptyArguments(MethodInvocationTree tree, VisitorState state) {
-    return tree.getArguments().stream().anyMatch(arg -> EMPTY_MONO.matches(arg, state));
-  }
-}
--- a/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/ErrorProneRuntimeClasspath.java
+++ b/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/ErrorProneRuntimeClasspath.java
@@ -1,11 +1,11 @@
-package tech.picnic.errorprone.guidelines.bugpatterns;
+package tech.picnic.errorprone.bugpatterns;

 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
 import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
 import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
 import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -26,9 +26,9 @@ import com.sun.source.tree.LiteralTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.ClassSymbol;
+import com.sun.tools.javac.util.Constants;
 import java.util.regex.Pattern;
-import tech.picnic.errorprone.utils.SourceCode;
-import tech.picnic.errorprone.utils.ThirdPartyLibrary;
+import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;

 /**
 * A {@link BugChecker} that flags literal strings in Error Prone Support code that represent the
@@ -50,9 +50,8 @@ import tech.picnic.errorprone.utils.ThirdPartyLibrary;
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        Prefer `Class#getCanonicalName()` over an equivalent string literal if and only if the \
-        type will be on the runtime classpath""",
+        "Prefer `Class#getCanonicalName()` over an equivalent string literal if and only if the "
+            + "type will be on the runtime classpath",
    link = BUG_PATTERNS_BASE_URL + "ErrorProneRuntimeClasspath",
    linkType = CUSTOM,
    severity = SUGGESTION,
@@ -123,8 +122,7 @@ public final class ErrorProneRuntimeClasspath extends BugChecker
        .setMessage("This type may not be on the runtime classpath; use a string literal instead")
        .addFix(
            SuggestedFix.replace(
-                tree,
-                SourceCode.toStringConstantExpression(receiver.owner.getQualifiedName(), state)))
+                tree, Constants.format(receiver.owner.getQualifiedName().toString())))
        .build();
  }

@@ -151,9 +149,7 @@ public final class ErrorProneRuntimeClasspath extends BugChecker
            original,
            identifier
                + ".class.getCanonicalName()"
-                + (suffix.isEmpty()
-                    ? ""
-                    : (" + " + SourceCode.toStringConstantExpression(suffix, state))))
+                + (suffix.isEmpty() ? "" : (" + " + Constants.format(suffix))))
        .build();
  }

--- a/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/ErrorProneTestHelperSourceFormat.java
+++ b/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/ErrorProneTestHelperSourceFormat.java
@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.guidelines.bugpatterns;
+package tech.picnic.errorprone.bugpatterns;

 import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
 import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
@@ -7,7 +7,7 @@ import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.instanceMethod;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
 import static java.util.stream.Collectors.joining;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ExplicitArgumentEnumeration.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ExplicitArgumentEnumeration.java
@@ -1,233 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.common.collect.ImmutableList.toImmutableList;
-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.BugPattern.StandardTags.SIMPLIFICATION;
-import static com.google.errorprone.matchers.Matchers.allOf;
-import static com.google.errorprone.matchers.Matchers.anyOf;
-import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static com.google.errorprone.matchers.Matchers.symbolMatcher;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
-
-import com.google.auto.service.AutoService;
-import com.google.common.collect.ImmutableCollection;
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMultiset;
-import com.google.common.collect.ImmutableSet;
-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.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.util.ASTHelpers;
-import com.google.errorprone.util.Visibility;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.MethodInvocationTree;
-import com.sun.source.tree.MethodTree;
-import com.sun.tools.javac.code.Symbol.MethodSymbol;
-import com.sun.tools.javac.code.Symbol.VarSymbol;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.Optional;
-import java.util.Set;
-import javax.lang.model.element.Element;
-import tech.picnic.errorprone.utils.SourceCode;
-
-/**
- * A {@link BugChecker} that flags single-argument method invocations with an iterable of explicitly
- * enumerated values, for which a semantically equivalent varargs variant (appears to) exists as
- * well.
- *
- * <p>This check drops selected {@link ImmutableSet#of} and {@link Set#of} invocations, with the
- * assumption that these operations do not deduplicate the collection of explicitly enumerated
- * values. It also drops {@link ImmutableMultiset#of} and {@link Set#of} invocations, with the
- * assumption that these do not materially impact iteration order.
- *
- * <p>This checker attempts to identify {@link Iterable}-accepting methods for which a varargs
- * overload exists, and suggests calling the varargs overload instead. This is an imperfect
- * heuristic, but it e.g. allows invocations of <a
- * href="https://immutables.github.io/immutable.html#copy-methods">Immutables-generated {@code
- * with*}</a> methods to be simplified.
- */
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "Iterable creation can be avoided by using a varargs alternative method",
-    link = BUG_PATTERNS_BASE_URL + "ExplicitArgumentEnumeration",
-    linkType = CUSTOM,
-    severity = SUGGESTION,
-    tags = {PERFORMANCE, SIMPLIFICATION})
-public final class ExplicitArgumentEnumeration extends BugChecker
-    implements MethodInvocationTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Matcher<ExpressionTree> EXPLICIT_ITERABLE_CREATOR =
-      anyOf(
-          staticMethod()
-              .onClassAny(
-                  ImmutableList.class.getCanonicalName(),
-                  ImmutableMultiset.class.getCanonicalName(),
-                  ImmutableSet.class.getCanonicalName(),
-                  List.class.getCanonicalName(),
-                  Set.class.getCanonicalName())
-              .named("of"),
-          allOf(
-              staticMethod()
-                  .onClassAny(
-                      ImmutableList.class.getCanonicalName(),
-                      ImmutableMultiset.class.getCanonicalName(),
-                      ImmutableSet.class.getCanonicalName())
-                  .named("copyOf"),
-              symbolMatcher(
-                  (symbol, state) ->
-                      state
-                          .getSymtab()
-                          .arrayClass
-                          .equals(((MethodSymbol) symbol).params().get(0).type.tsym))),
-          staticMethod().onClass(Arrays.class.getCanonicalName()).named("asList"));
-  private static final Matcher<ExpressionTree> IMMUTABLE_COLLECTION_BUILDER =
-      instanceMethod().onDescendantOf(ImmutableCollection.Builder.class.getCanonicalName());
-  private static final Matcher<ExpressionTree> OBJECT_ENUMERABLE_ASSERT =
-      instanceMethod().onDescendantOf("org.assertj.core.api.ObjectEnumerableAssert");
-  private static final Matcher<ExpressionTree> STEP_VERIFIER_STEP =
-      instanceMethod().onDescendantOf("reactor.test.StepVerifier.Step");
-  private static final ImmutableTable<Matcher<ExpressionTree>, String, String> ALTERNATIVE_METHODS =
-      ImmutableTable.<Matcher<ExpressionTree>, String, String>builder()
-          .put(IMMUTABLE_COLLECTION_BUILDER, "addAll", "add")
-          .put(OBJECT_ENUMERABLE_ASSERT, "containsAnyElementsOf", "containsAnyOf")
-          .put(OBJECT_ENUMERABLE_ASSERT, "containsAll", "contains")
-          .put(OBJECT_ENUMERABLE_ASSERT, "containsExactlyElementsOf", "containsExactly")
-          .put(
-              OBJECT_ENUMERABLE_ASSERT,
-              "containsExactlyInAnyOrderElementsOf",
-              "containsExactlyInAnyOrder")
-          .put(OBJECT_ENUMERABLE_ASSERT, "containsOnlyElementsOf", "containsOnly")
-          .put(OBJECT_ENUMERABLE_ASSERT, "containsOnlyOnceElementsOf", "containsOnlyOnce")
-          .put(OBJECT_ENUMERABLE_ASSERT, "doesNotContainAnyElementsOf", "doesNotContain")
-          .put(OBJECT_ENUMERABLE_ASSERT, "hasSameElementsAs", "containsOnly")
-          .put(STEP_VERIFIER_STEP, "expectNextSequence", "expectNext")
-          .buildOrThrow();
-
-  /** Instantiates a new {@link ExplicitArgumentEnumeration} instance. */
-  public ExplicitArgumentEnumeration() {}
-
-  @Override
-  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    if (tree.getArguments().size() != 1) {
-      /* Performance optimization: non-unary method invocations cannot be simplified. */
-      return Description.NO_MATCH;
-    }
-
-    MethodSymbol method = ASTHelpers.getSymbol(tree);
-    if (!isUnaryIterableAcceptingMethod(method, state) || isLocalOverload(method, state)) {
-      /*
-       * This isn't a method invocation we can simplify, or it's an invocation of a local overload.
-       * The latter type of invocation we do not suggest replacing, as this is fairly likely to
-       * introduce an unbounded recursive call chain.
-       */
-      return Description.NO_MATCH;
-    }
-
-    ExpressionTree argument = tree.getArguments().get(0);
-    if (!EXPLICIT_ITERABLE_CREATOR.matches(argument, state)) {
-      return Description.NO_MATCH;
-    }
-
-    return trySuggestCallingVarargsOverload(method, (MethodInvocationTree) argument, state)
-        .or(() -> trySuggestCallingCustomAlternative(tree, (MethodInvocationTree) argument, state))
-        .map(fix -> describeMatch(tree, fix))
-        .orElse(Description.NO_MATCH);
-  }
-
-  private static boolean isUnaryIterableAcceptingMethod(MethodSymbol method, VisitorState state) {
-    List<VarSymbol> params = method.params();
-    return !method.isVarArgs()
-        && params.size() == 1
-        && ASTHelpers.isSubtype(params.get(0).type, state.getSymtab().iterableType, state);
-  }
-
-  private static boolean isLocalOverload(MethodSymbol calledMethod, VisitorState state) {
-    MethodTree enclosingMethod = state.findEnclosing(MethodTree.class);
-    if (enclosingMethod == null) {
-      return false;
-    }
-
-    MethodSymbol callingMethod = ASTHelpers.getSymbol(enclosingMethod);
-    return Objects.equals(callingMethod.getEnclosingElement(), calledMethod.getEnclosingElement())
-        && callingMethod.getSimpleName().equals(calledMethod.getSimpleName());
-  }
-
-  private static Optional<SuggestedFix> trySuggestCallingVarargsOverload(
-      MethodSymbol method, MethodInvocationTree argument, VisitorState state) {
-    /*
-     * Collect all overloads of the given method that we are sure to be able to call. Note that the
-     * `isAtLeastAsVisible` check is conservative heuristic.
-     */
-    ImmutableList<MethodSymbol> overloads =
-        ASTHelpers.matchingMethods(
-                method.getSimpleName(),
-                m -> isAtLeastAsVisible(m, method),
-                method.enclClass().type,
-                state.getTypes())
-            .collect(toImmutableList());
-
-    /*
-     * If all overloads have a single parameter, and at least one of them is a varargs method, then
-     * we assume that unwrapping the iterable argument will cause a suitable overload to be invoked.
-     * (Note that there may be multiple varargs overloads, either with different parameter types, or
-     * due to method overriding; this check does not attempt to determine which exact method or
-     * overload will be invoked as a result of the suggested simplification.)
-     *
-     * Note that this is a (highly!) imperfect heuristic, but it is sufficient to prevent e.g.
-     * unwrapping of arguments to `org.jooq.impl.DSL#row`, which can cause the expression's return
-     * type to change from `RowN` to (e.g.) `Row2`.
-     */
-    // XXX: There are certainly cases where it _would_ be nice to unwrap the arguments to
-    // `org.jooq.impl.DSL#row(Collection<?>)`. Look into this.
-    // XXX: Ideally we do check that one of the overloads accepts the unwrapped arguments.
-    // XXX: Ideally we validate that eligible overloads have compatible return types.
-    boolean hasLikelySuitableVarargsOverload =
-        overloads.stream().allMatch(m -> m.params().size() == 1)
-            && overloads.stream().anyMatch(MethodSymbol::isVarArgs);
-
-    return hasLikelySuitableVarargsOverload
-        ? Optional.of(SourceCode.unwrapMethodInvocation(argument, state))
-        : Optional.empty();
-  }
-
-  private static Optional<SuggestedFix> trySuggestCallingCustomAlternative(
-      MethodInvocationTree tree, MethodInvocationTree argument, VisitorState state) {
-    return ALTERNATIVE_METHODS.rowMap().entrySet().stream()
-        .filter(e -> e.getKey().matches(tree, state))
-        .findFirst()
-        .flatMap(e -> trySuggestCallingCustomAlternative(tree, argument, state, e.getValue()));
-  }
-
-  private static Optional<SuggestedFix> trySuggestCallingCustomAlternative(
-      MethodInvocationTree tree,
-      MethodInvocationTree argument,
-      VisitorState state,
-      Map<String, String> alternatives) {
-    return Optional.ofNullable(
-            alternatives.get(ASTHelpers.getSymbol(tree).getSimpleName().toString()))
-        .map(
-            replacement ->
-                SuggestedFix.builder()
-                    .merge(SuggestedFixes.renameMethodInvocation(tree, replacement, state))
-                    .merge(SourceCode.unwrapMethodInvocation(argument, state))
-                    .build());
-  }
-
-  private static boolean isAtLeastAsVisible(Element symbol, Element reference) {
-    return Visibility.fromModifiers(symbol.getModifiers())
-            .compareTo(Visibility.fromModifiers(reference.getModifiers()))
-        >= 0;
-  }
-}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ExplicitEnumOrdering.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -72,7 +72,7 @@ public final class ExplicitEnumOrdering extends BugChecker implements MethodInvo
      List<? extends ExpressionTree> expressions) {
    return expressions.stream()
        .map(ASTHelpers::getSymbol)
-        .filter(s -> s != null && s.isEnum())
+        .filter(Symbol::isEnum)
        .collect(
            collectingAndThen(
                toImmutableSetMultimap(Symbol::asType, Symbol::toString),
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FluxFlatMapUsage.java
+++ b/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.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 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 com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
@@ -50,9 +50,8 @@ import reactor.core.publisher.Flux;
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        `Flux#flatMap` and `Flux#flatMapSequential` have subtle semantics; please use \
-        `Flux#concatMap` or explicitly specify the desired amount of concurrency""",
+        "`Flux#flatMap` and `Flux#flatMapSequential` have subtle semantics; "
+            + "please use `Flux#concatMap` or explicitly specify the desired amount of concurrency",
    link = BUG_PATTERNS_BASE_URL + "FluxFlatMapUsage",
    linkType = CUSTOM,
    severity = ERROR,
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FluxImplicitBlock.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FluxImplicitBlock.java
@@ -6,7 +6,7 @@ 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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableList;
@@ -27,7 +27,7 @@ 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;
+import tech.picnic.errorprone.bugpatterns.util.ThirdPartyLibrary;

 /**
 * A {@link BugChecker} that flags {@link reactor.core.publisher.Flux} operator usages that may
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FormatStringConcatenation.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/FormatStringConcatenation.java
@@ -10,7 +10,7 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.Preconditions;
@@ -31,13 +31,13 @@ import com.sun.source.tree.ParenthesizedTree;
 import com.sun.source.tree.Tree;
 import com.sun.source.tree.Tree.Kind;
 import com.sun.source.util.SimpleTreeVisitor;
+import com.sun.tools.javac.code.Type;
 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.utils.MoreASTHelpers;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags string concatenations that produce a format string; in such cases
@@ -204,10 +204,16 @@ public final class FormatStringConcatenation extends BugChecker

    ExpressionTree argument = ASTHelpers.stripParentheses(arguments.get(argPosition));
    return argument instanceof BinaryTree
-        && MoreASTHelpers.isStringTyped(argument, state)
+        && isStringTyped(argument, state)
        && ASTHelpers.constValue(argument, String.class) == null;
  }

+  private static boolean isStringTyped(ExpressionTree tree, VisitorState state) {
+    // XXX: Open Error Prone PR to improve the `@Nullable` annotations on `ASTHelpers`.
+    Type type = ASTHelpers.getType(tree);
+    return type != null && ASTHelpers.isSameType(type, state.getSymtab().stringType, state);
+  }
+
  private static class ReplacementArgumentsConstructor
      extends SimpleTreeVisitor<@Nullable Void, VisitorState> {
    private final StringBuilder formatString = new StringBuilder();
@@ -220,7 +226,7 @@ public final class FormatStringConcatenation extends BugChecker

    @Override
    public @Nullable Void visitBinary(BinaryTree tree, VisitorState state) {
-      if (tree.getKind() == Kind.PLUS && MoreASTHelpers.isStringTyped(tree, state)) {
+      if (tree.getKind() == Kind.PLUS && isStringTyped(tree, state)) {
        tree.getLeftOperand().accept(this, state);
        tree.getRightOperand().accept(this, state);
      } else {
@@ -242,8 +248,8 @@ public final class FormatStringConcatenation extends BugChecker
    }

    private void appendExpression(Tree tree) {
-      if (tree instanceof LiteralTree literal) {
-        formatString.append(literal.getValue());
+      if (tree instanceof LiteralTree) {
+        formatString.append(((LiteralTree) tree).getValue());
      } else {
        formatString.append(formatSpecifier);
        formatArguments.add(tree);
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/IdentityConversion.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/IdentityConversion.java
@@ -7,7 +7,7 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableBiMap;
@@ -39,10 +39,9 @@ import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.tools.javac.code.Type;
 import com.sun.tools.javac.code.Types;
-import java.time.Instant;
 import java.util.Arrays;
 import java.util.List;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /** A {@link BugChecker} that flags redundant identity conversions. */
 // XXX: Consider detecting cases where a flagged expression is passed to a method, and where removal
@@ -52,7 +51,6 @@ import tech.picnic.errorprone.utils.SourceCode;
 // 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.
-// XXX: Also flag redundant round-trip conversions such as `path.toFile().toPath()`.
@AutoService(BugChecker.class)
@BugPattern(
    summary = "Avoid or clarify identity conversions",
@@ -85,7 +83,6 @@ public final class IdentityConversion extends BugChecker implements MethodInvoca
                  ImmutableSetMultimap.class.getCanonicalName(),
                  ImmutableTable.class.getCanonicalName())
              .named("copyOf"),
-          staticMethod().onClass(Instant.class.getCanonicalName()).namedAnyOf("from"),
          staticMethod().onClass(Matchers.class.getCanonicalName()).namedAnyOf("allOf", "anyOf"),
          staticMethod().onClass("reactor.adapter.rxjava.RxJava2Adapter"),
          staticMethod()
@@ -127,9 +124,8 @@ public final class IdentityConversion extends BugChecker implements MethodInvoca

    return buildDescription(tree)
        .setMessage(
-            """
-            This method invocation appears redundant; remove it or suppress this warning and add a \
-            comment explaining its purpose""")
+            "This method invocation appears redundant; remove it or suppress this warning and "
+                + "add a comment explaining its purpose")
        .addFix(SuggestedFix.replace(tree, SourceCode.treeToString(sourceTree, state)))
        .addFix(SuggestedFixes.addSuppressWarnings(state, canonicalName()))
        .build();
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/ImmutablesSortedSetComparator.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -43,9 +43,8 @@ import javax.lang.model.element.Modifier;
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        `SortedSet` properties of a `@Value.Immutable` or `@Value.Modifiable` type must be \
-        annotated with `@Value.NaturalOrder` or `@Value.ReverseOrder`""",
+        "`SortedSet` properties of a `@Value.Immutable` or `@Value.Modifiable` type must be "
+            + "annotated with `@Value.NaturalOrder` or `@Value.ReverseOrder`",
    link = BUG_PATTERNS_BASE_URL + "ImmutablesSortedSetComparator",
    linkType = CUSTOM,
    severity = ERROR,
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/IsInstanceLambdaUsage.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.Iterables;
@@ -16,17 +16,17 @@ import com.google.errorprone.matchers.Description;
 import com.google.errorprone.util.ASTHelpers;
 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.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.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 of the
-// `error-prone-experimental` module.
-// XXX: This check and its tests are structurally nearly identical to `ClassCastLambdaUsage`. Unless
-// folded into `MethodReferenceUsage`, consider merging the two.
+// XXX: Consider folding this logic into the `MethodReferenceUsage` check.
@AutoService(BugChecker.class)
@BugPattern(
    summary = "Prefer `Class::isInstance` method reference over equivalent lambda expression",
@@ -42,12 +42,12 @@ public final class IsInstanceLambdaUsage extends BugChecker implements LambdaExp

  @Override
  public Description matchLambdaExpression(LambdaExpressionTree tree, VisitorState state) {
-    if (tree.getParameters().size() != 1
-        || !(tree.getBody() instanceof InstanceOfTree instanceOf)) {
+    if (tree.getParameters().size() != 1 || tree.getBody().getKind() != Kind.INSTANCE_OF) {
      return Description.NO_MATCH;
    }

    VariableTree param = Iterables.getOnlyElement(tree.getParameters());
+    InstanceOfTree instanceOf = (InstanceOfTree) tree.getBody();
    if (!ASTHelpers.getSymbol(param).equals(ASTHelpers.getSymbol(instanceOf.getExpression()))) {
      return Description.NO_MATCH;
    }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitClassModifiers.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitClassModifiers.java
@@ -11,12 +11,12 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
-import static tech.picnic.errorprone.utils.MoreJUnitMatchers.TEST_METHOD;
-import static tech.picnic.errorprone.utils.MoreMatchers.hasMetaAnnotation;
+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 com.google.auto.service.AutoService;
-import com.google.common.collect.Sets;
+import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker;
@@ -70,7 +70,7 @@ public final class JUnitClassModifiers extends BugChecker implements ClassTreeMa
    SuggestedFixes.removeModifiers(
            tree.getModifiers(),
            state,
-            Sets.immutableEnumSet(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC))
+            ImmutableSet.of(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC))
        .ifPresent(fixBuilder::merge);

    if (!HAS_SPRING_CONFIGURATION_ANNOTATION.matches(tree, state)) {
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitMethodDeclaration.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitMethodDeclaration.java
@@ -8,9 +8,9 @@ import static com.google.errorprone.matchers.Matchers.enclosingClass;
 import static com.google.errorprone.matchers.Matchers.hasModifier;
 import static com.google.errorprone.matchers.Matchers.not;
 import static java.util.function.Predicate.not;
-import static tech.picnic.errorprone.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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.SETUP_OR_TEARDOWN_METHOD;
+import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.TEST_METHOD;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -28,7 +28,7 @@ import com.sun.source.tree.MethodTree;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import java.util.Optional;
 import javax.lang.model.element.Modifier;
-import tech.picnic.errorprone.utils.ConflictDetection;
+import tech.picnic.errorprone.bugpatterns.util.ConflictDetection;

 /** A {@link BugChecker} that flags non-canonical JUnit method declarations. */
 // XXX: Consider introducing a class-level check that enforces that test classes:
@@ -101,8 +101,6 @@ public final class JUnitMethodDeclaration extends BugChecker implements MethodTr
            .build());
  }

-  // XXX: Consider dropping leading underscores that otherwise result when canonicalizing
-  // `test_some_method_name`.
  private static Optional<String> tryCanonicalizeMethodName(MethodSymbol symbol) {
    return Optional.of(symbol.getQualifiedName().toString())
        .filter(name -> name.startsWith(TEST_PREFIX))
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitNullaryParameterizedTestDeclaration.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitNullaryParameterizedTestDeclaration.java
@@ -7,8 +7,8 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
-import static tech.picnic.errorprone.utils.MoreMatchers.hasMetaAnnotation;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreMatchers.hasMetaAnnotation;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -23,7 +23,7 @@ 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;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags nullary {@link
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitValueSource.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/JUnitValueSource.java
@@ -19,9 +19,9 @@ 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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.HAS_METHOD_SOURCE;
+import static tech.picnic.errorprone.bugpatterns.util.MoreJUnitMatchers.getMethodSourceFactoryNames;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableList;
@@ -58,7 +58,7 @@ import java.util.stream.IntStream;
 import java.util.stream.LongStream;
 import java.util.stream.Stream;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags JUnit tests with a {@link
@@ -171,6 +171,9 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
    return findMatchingSibling(tree, m -> m.getName().contentEquals(methodName), state);
  }

+  // XXX: File ticket for the `@SuppressWarnings`: the checker incorrectly claims that the predicate
+  // only accepts `@InternedDistinct @SignatureBottom MethodTree` values (IIUC).
+  @SuppressWarnings({"interning:argument", "signature:argument"})
  private static Optional<MethodTree> findMatchingSibling(
      MethodTree tree, Predicate<? super MethodTree> predicate, VisitorState state) {
    return state.findEnclosing(ClassTree.class).getMembers().stream()
@@ -232,7 +235,7 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
      @Override
      public @Nullable Void visitReturn(ReturnTree node, @Nullable Void unused) {
        returnExpressions.add(node.getExpression());
-        return super.visitReturn(node, null);
+        return super.visitReturn(node, unused);
      }

      @Override
@@ -265,8 +268,8 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
            arguments.stream()
                .map(
                    arg ->
-                        arg instanceof MethodInvocationTree methodInvocation
-                            ? Iterables.getOnlyElement(methodInvocation.getArguments())
+                        arg instanceof MethodInvocationTree
+                            ? Iterables.getOnlyElement(((MethodInvocationTree) arg).getArguments())
                            : arg)
                .map(argument -> SourceCode.treeToString(argument, state))
                .collect(joining(", ")))
@@ -276,12 +279,16 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
  private static String toValueSourceAttributeName(Type type) {
    String typeString = type.tsym.name.toString();

-    return switch (typeString) {
-      case "Class" -> "classes";
-      case "Character" -> "chars";
-      case "Integer" -> "ints";
-      default -> typeString.toLowerCase(Locale.ROOT) + 's';
-    };
+    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) {
@@ -293,10 +300,11 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
  private static Matcher<ExpressionTree> isSingleDimensionArrayCreationWithAllElementsMatching(
      Matcher<? super ExpressionTree> elementMatcher) {
    return (tree, state) -> {
-      if (!(tree instanceof NewArrayTree newArray)) {
+      if (!(tree instanceof NewArrayTree)) {
        return false;
      }

+      NewArrayTree newArray = (NewArrayTree) tree;
      return newArray.getDimensions().isEmpty()
          && !newArray.getInitializers().isEmpty()
          && newArray.getInitializers().stream()
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationAttributeListing.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationAttributeListing.java
@@ -7,14 +7,13 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
 import com.google.common.collect.Comparators;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Sets;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
@@ -32,17 +31,20 @@ import com.sun.source.tree.LiteralTree;
 import com.sun.source.tree.NewArrayTree;
 import com.sun.source.tree.PrimitiveTypeTree;
 import com.sun.source.tree.Tree;
+import com.sun.source.tree.Tree.Kind;
 import com.sun.source.util.TreeScanner;
 import com.sun.tools.javac.code.Symtab;
 import com.sun.tools.javac.code.Type;
+import java.util.HashSet;
 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.utils.AnnotationAttributeMatcher;
-import tech.picnic.errorprone.utils.Flags;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.bugpatterns.util.Flags;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags annotation array listings which aren't sorted lexicographically.
@@ -50,9 +52,6 @@ import tech.picnic.errorprone.utils.SourceCode;
 * <p>The idea behind this checker is that maintaining a sorted sequence simplifies conflict
 * resolution, and can even avoid it if two branches add the same entry.
 */
-// XXX: In some places we declare a `@SuppressWarnings` annotation with a final value of
-// `key-to-resolve-AnnotationUseStyle-and-TrailingComment-check-conflict`. That entry must stay
-// last. Consider adding (generic?) support for such cases.
@AutoService(BugChecker.class)
@BugPattern(
    summary = "Where possible, sort annotation array attributes lexicographically",
@@ -66,15 +65,14 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
  private static final long serialVersionUID = 1L;
  private static final ImmutableSet<String> BLACKLISTED_ANNOTATIONS =
      ImmutableSet.of(
-          // XXX: Unless `JsonPropertyOrder#alphabetic` is true...
+          // XXX: unless JsonPropertyOrder#alphabetic is true...
          "com.fasterxml.jackson.annotation.JsonPropertyOrder#value",
          "io.swagger.annotations.ApiImplicitParams#value",
          "io.swagger.v3.oas.annotations.Parameters#value",
          "javax.xml.bind.annotation.XmlType#propOrder",
          "org.springframework.context.annotation.PropertySource#value",
          "org.springframework.test.context.TestPropertySource#locations",
-          "org.springframework.test.context.TestPropertySource#value",
-          "picocli.CommandLine.Option#names");
+          "org.springframework.test.context.TestPropertySource#value");
  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";
@@ -124,9 +122,13 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
  }

  private static Optional<NewArrayTree> extractArray(ExpressionTree expr) {
-    return expr instanceof AssignmentTree assignment
-        ? extractArray(assignment.getExpression())
-        : Optional.of(expr).filter(NewArrayTree.class::isInstance).map(NewArrayTree.class::cast);
+    if (expr.getKind() == Kind.ASSIGNMENT) {
+      return extractArray(((AssignmentTree) expr).getExpression());
+    }
+
+    return Optional.of(expr)
+        .filter(e -> e.getKind() == Kind.NEW_ARRAY)
+        .map(NewArrayTree.class::cast);
  }

  private static Optional<SuggestedFix.Builder> suggestSorting(
@@ -162,12 +164,7 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker

    /* For now we don't force sorting on numeric types. */
    return Stream.of(
-            symtab.annotationType,
-            symtab.booleanType,
-            symtab.charType,
-            symtab.classType,
-            symtab.enumSym.type,
-            symtab.stringType)
+            symtab.annotationType, symtab.classType, symtab.enumSym.type, symtab.stringType)
        .anyMatch(t -> ASTHelpers.isSubtype(elemType, t, state));
  }

@@ -196,24 +193,24 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
      @Override
      public @Nullable Void visitIdentifier(IdentifierTree node, @Nullable Void unused) {
        nodes.add(ImmutableList.of(node.getName().toString()));
-        return super.visitIdentifier(node, null);
+        return super.visitIdentifier(node, unused);
      }

      @Override
      public @Nullable Void visitLiteral(LiteralTree node, @Nullable Void unused) {
        Object value = ASTHelpers.constValue(node);
        nodes.add(
-            value instanceof String str
-                ? STRING_ARGUMENT_SPLITTER.splitToStream(str).collect(toImmutableList())
+            value instanceof String
+                ? STRING_ARGUMENT_SPLITTER.splitToStream((String) value).collect(toImmutableList())
                : ImmutableList.of(String.valueOf(value)));

-        return super.visitLiteral(node, null);
+        return super.visitLiteral(node, unused);
      }

      @Override
      public @Nullable Void visitPrimitiveType(PrimitiveTypeTree node, @Nullable Void unused) {
        nodes.add(ImmutableList.of(node.getPrimitiveTypeKind().toString()));
-        return super.visitPrimitiveType(node, null);
+        return super.visitPrimitiveType(node, unused);
      }
    }.scan(array, null);

@@ -229,8 +226,10 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
        excludedAnnotations(flags));
  }

-  private static ImmutableSet<String> excludedAnnotations(ErrorProneFlags flags) {
-    return Sets.union(BLACKLISTED_ANNOTATIONS, Flags.getSet(flags, EXCLUDED_ANNOTATIONS_FLAG))
-        .immutableCopy();
+  private static ImmutableList<String> excludedAnnotations(ErrorProneFlags flags) {
+    Set<String> exclusions = new HashSet<>();
+    exclusions.addAll(Flags.getList(flags, EXCLUDED_ANNOTATIONS_FLAG));
+    exclusions.addAll(BLACKLISTED_ANNOTATIONS);
+    return ImmutableList.copyOf(exclusions);
  }
 }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationListing.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.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.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags annotations that are not lexicographically sorted.
@@ -36,10 +36,6 @@ import tech.picnic.errorprone.utils.SourceCode;
 * <p>The idea behind this checker is that maintaining a sorted sequence simplifies conflict
 * resolution, and can even avoid it if two branches add the same annotation.
 */
-// XXX: Currently this checker only flags method-level annotations. It should likely also flag
-// type-, field- and parameter-level annotations.
-// XXX: Duplicate entries are often a mistake. Consider introducing a similar `BugChecker` that
-// flags duplicates.
@AutoService(BugChecker.class)
@BugPattern(
    summary = "Sort annotations lexicographically where possible",
--- a/error-prone-experimental/src/main/java/tech/picnic/errorprone/experimental/bugpatterns/MethodReferenceUsage.java
+++ b/error-prone-experimental/src/main/java/tech/picnic/errorprone/experimental/bugpatterns/MethodReferenceUsage.java
@@ -1,10 +1,10 @@
-package tech.picnic.errorprone.experimental.bugpatterns;
+package tech.picnic.errorprone.bugpatterns;

 import static com.google.common.collect.ImmutableList.toImmutableList;
 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
@@ -27,15 +27,19 @@ import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.ParenthesizedTree;
 import com.sun.source.tree.ReturnTree;
 import com.sun.source.tree.Tree;
+import com.sun.source.tree.Tree.Kind;
 import com.sun.source.tree.VariableTree;
 import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Type;
 import java.util.List;
 import java.util.Optional;
 import javax.lang.model.element.Name;
+import org.checkerframework.checker.nullness.qual.NonNull;

 /**
 * A {@link BugChecker} that flags lambda expressions that can be replaced with method references.
+ *
+ * @see IsInstanceLambdaUsage
 */
 // XXX: Other custom expressions we could rewrite:
 // - `a -> "str" + a` to `"str"::concat`. But only if `str` is provably non-null.
@@ -51,8 +55,7 @@ import javax.lang.model.element.Name;
 // Palantir's `LambdaMethodReference` check seems to suffer a similar issue at this time.
 // XXX: Expressions of the form `i -> SomeType.class.isInstance(i)` are not replaced; fix that using
 // a suitable generalization.
-// XXX: Consider folding the `IsInstanceLambdaUsage` check of the `error-prone-contrib` module into
-// this class.
+// XXX: Consider folding the `IsInstanceLambdaUsage` check into this class.
@AutoService(BugChecker.class)
@BugPattern(
    summary = "Prefer method references over lambda expressions",
@@ -83,19 +86,22 @@ public final class MethodReferenceUsage extends BugChecker implements LambdaExpr
        .orElse(Description.NO_MATCH);
  }

-  // XXX: Use switch pattern matching once the targeted JDK supports this.
  private static Optional<SuggestedFix.Builder> constructMethodRef(
      LambdaExpressionTree lambdaExpr, Tree subTree) {
-    return switch (subTree.getKind()) {
-      case BLOCK -> constructMethodRef(lambdaExpr, (BlockTree) subTree);
-      case EXPRESSION_STATEMENT ->
-          constructMethodRef(lambdaExpr, ((ExpressionStatementTree) subTree).getExpression());
-      case METHOD_INVOCATION -> constructMethodRef(lambdaExpr, (MethodInvocationTree) subTree);
-      case PARENTHESIZED ->
-          constructMethodRef(lambdaExpr, ((ParenthesizedTree) subTree).getExpression());
-      case RETURN -> constructMethodRef(lambdaExpr, ((ReturnTree) subTree).getExpression());
-      default -> Optional.empty();
-    };
+    switch (subTree.getKind()) {
+      case BLOCK:
+        return constructMethodRef(lambdaExpr, (BlockTree) subTree);
+      case EXPRESSION_STATEMENT:
+        return constructMethodRef(lambdaExpr, ((ExpressionStatementTree) subTree).getExpression());
+      case METHOD_INVOCATION:
+        return constructMethodRef(lambdaExpr, (MethodInvocationTree) subTree);
+      case PARENTHESIZED:
+        return constructMethodRef(lambdaExpr, ((ParenthesizedTree) subTree).getExpression());
+      case RETURN:
+        return constructMethodRef(lambdaExpr, ((ReturnTree) subTree).getExpression());
+      default:
+        return Optional.empty();
+    }
  }

  private static Optional<SuggestedFix.Builder> constructMethodRef(
@@ -113,35 +119,33 @@ public final class MethodReferenceUsage extends BugChecker implements LambdaExpr
        .flatMap(expectedInstance -> constructMethodRef(lambdaExpr, subTree, expectedInstance));
  }

-  // XXX: Review whether to use switch pattern matching once the targeted JDK supports this.
+  @SuppressWarnings(
+      "java:S1151" /* Extracting `IDENTIFIER` case block to separate method does not improve readability. */)
  private static Optional<SuggestedFix.Builder> constructMethodRef(
      LambdaExpressionTree lambdaExpr,
      MethodInvocationTree subTree,
      Optional<Name> expectedInstance) {
    ExpressionTree methodSelect = subTree.getMethodSelect();
-
-    if (methodSelect instanceof IdentifierTree) {
-      if (expectedInstance.isPresent()) {
-        /* Direct method call; there is no matching "implicit parameter". */
-        return Optional.empty();
-      }
-
-      Symbol sym = ASTHelpers.getSymbol(methodSelect);
-      return ASTHelpers.isStatic(sym)
-          ? constructFix(lambdaExpr, sym.owner, methodSelect)
-          : constructFix(lambdaExpr, "this", methodSelect);
+    switch (methodSelect.getKind()) {
+      case IDENTIFIER:
+        if (expectedInstance.isPresent()) {
+          /* Direct method call; there is no matching "implicit parameter". */
+          return Optional.empty();
+        }
+        Symbol sym = ASTHelpers.getSymbol(methodSelect);
+        return ASTHelpers.isStatic(sym)
+            ? constructFix(lambdaExpr, sym.owner, methodSelect)
+            : constructFix(lambdaExpr, "this", methodSelect);
+      case MEMBER_SELECT:
+        return constructMethodRef(lambdaExpr, (MemberSelectTree) methodSelect, expectedInstance);
+      default:
+        throw new VerifyException("Unexpected type of expression: " + methodSelect.getKind());
    }
-
-    if (methodSelect instanceof MemberSelectTree memberSelect) {
-      return constructMethodRef(lambdaExpr, memberSelect, expectedInstance);
-    }
-
-    throw new VerifyException("Unexpected type of expression: " + methodSelect.getKind());
  }

  private static Optional<SuggestedFix.Builder> constructMethodRef(
      LambdaExpressionTree lambdaExpr, MemberSelectTree subTree, Optional<Name> expectedInstance) {
-    if (!(subTree.getExpression() instanceof IdentifierTree identifier)) {
+    if (subTree.getExpression().getKind() != Kind.IDENTIFIER) {
      // XXX: Could be parenthesized. Handle. Also in other classes.
      /*
       * Only suggest a replacement if the method select's expression provably doesn't have
@@ -150,12 +154,12 @@ public final class MethodReferenceUsage extends BugChecker implements LambdaExpr
      return Optional.empty();
    }

-    Name lhs = identifier.getName();
+    Name lhs = ((IdentifierTree) subTree.getExpression()).getName();
    if (expectedInstance.isEmpty()) {
      return constructFix(lambdaExpr, lhs, subTree.getIdentifier());
    }

-    Type lhsType = ASTHelpers.getType(identifier);
+    Type lhsType = ASTHelpers.getType(subTree.getExpression());
    if (lhsType == null || !expectedInstance.orElseThrow().equals(lhs)) {
      return Optional.empty();
    }
@@ -180,13 +184,18 @@ public final class MethodReferenceUsage extends BugChecker implements LambdaExpr

    for (int i = 0; i < args.size(); i++) {
      ExpressionTree arg = args.get(i);
-      if (!(arg instanceof IdentifierTree identifier)
-          || !identifier.getName().equals(expectedArguments.get(i + diff))) {
+      if (arg.getKind() != Kind.IDENTIFIER
+          || !((IdentifierTree) arg).getName().equals(expectedArguments.get(i + diff))) {
        return Optional.empty();
      }
    }

-    return Optional.of(diff == 0 ? Optional.empty() : Optional.of(expectedArguments.get(0)));
+    // XXX: These type hints shouldn't be necessary; see
+    // https://github.com/typetools/checker-framework/issues/4007.
+    return Optional.of(
+        diff == 0
+            ? Optional.<@NonNull Name>empty()
+            : Optional.<@NonNull Name>of(expectedArguments.get(0)));
  }

  private static ImmutableList<Name> getVariables(LambdaExpressionTree tree) {
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MockitoMockClassReference.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MockitoMockClassReference.java
@@ -9,7 +9,7 @@ import static com.google.errorprone.matchers.Matchers.isSameType;
 import static com.google.errorprone.matchers.Matchers.isVariable;
 import static com.google.errorprone.matchers.Matchers.not;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -25,7 +25,7 @@ import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.Tree;
 import com.sun.source.tree.VariableTree;
 import java.util.List;
-import tech.picnic.errorprone.utils.MoreASTHelpers;
+import tech.picnic.errorprone.bugpatterns.util.MoreASTHelpers;

 /**
 * A {@link BugChecker} that flags the use of {@link org.mockito.Mockito#mock(Class)} and {@link
@@ -67,19 +67,20 @@ public final class MockitoMockClassReference extends BugChecker
    return describeMatch(tree, SuggestedFixes.removeElement(arguments.get(0), arguments, state));
  }

-  // XXX: Use switch pattern matching once the targeted JDK supports this.
  private static boolean isTypeDerivableFromContext(MethodInvocationTree tree, VisitorState state) {
    Tree parent = state.getPath().getParentPath().getLeaf();
-    return switch (parent.getKind()) {
-      case VARIABLE ->
-          !ASTHelpers.hasImplicitType((VariableTree) parent, state)
-              && MoreASTHelpers.areSameType(tree, parent, state);
-      case ASSIGNMENT -> MoreASTHelpers.areSameType(tree, parent, state);
-      case RETURN ->
-          MoreASTHelpers.findMethodExitedOnReturn(state)
-              .filter(m -> MoreASTHelpers.areSameType(tree, m.getReturnType(), state))
-              .isPresent();
-      default -> false;
-    };
+    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;
+    }
  }
 }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MockitoStubbing.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.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.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags method invocations for which all arguments are wrapped using
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MongoDBTextFilterUsage.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/MongoDBTextFilterUsage.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.PERFORMANCE;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -24,9 +24,7 @@ import com.sun.source.tree.MethodInvocationTree;
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        Avoid MongoDB's `$text` filter operator, as it can trigger heavy queries and even cause \
-        the server to run out of memory""",
+        "Avoid MongoDB's `$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,
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/NestedOptionals.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/NestedOptionals.java
@@ -3,11 +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.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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreMatchers.isSubTypeOf;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.generic;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.raw;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.subOf;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/NestedPublishers.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/NestedPublishers.java
@@ -6,13 +6,13 @@ 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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypePredicates.hasTypeParameter;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypePredicates.isSubTypeOf;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.generic;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.raw;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.subOf;
+import static tech.picnic.errorprone.bugpatterns.util.MoreTypes.type;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -34,9 +34,8 @@ import com.sun.tools.javac.code.Type;
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        Avoid `Publisher`s that emit other `Publishers`s; the resultant code is hard to reason \
-        about""",
+        "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,
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/NonEmptyMono.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.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.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags {@link Mono} operations that are known to be vacuous, given that
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/NonStaticImport.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/NonStaticImport.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.STYLE;
 import static tech.picnic.errorprone.bugpatterns.StaticImport.STATIC_IMPORT_CANDIDATE_MEMBERS;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.auto.value.AutoValue;
@@ -30,14 +30,12 @@ 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.InstantSource;
 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;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags static imports of type members that should *not* be statically
@@ -70,13 +68,10 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
      ImmutableSet.of(
          ASTHelpers.class.getCanonicalName(),
          Clock.class.getCanonicalName(),
-          InstantSource.class.getCanonicalName(),
          Strings.class.getCanonicalName(),
          VisitorState.class.getCanonicalName(),
          ZoneOffset.class.getCanonicalName(),
-          "com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode",
-          "reactor.core.publisher.Flux",
-          "reactor.core.publisher.Mono");
+          "com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode");

  /**
   * Type members that should never be statically imported.
@@ -108,7 +103,6 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
              "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")
@@ -131,7 +125,7 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
          "builder",
          "copyOf",
          "create",
-          "EPOCH",
+          "empty",
          "from",
          "getDefaultInstance",
          "INSTANCE",
@@ -142,8 +136,10 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
          "newBuilder",
          "newInstance",
          "of",
+          "ONE",
          "parse",
-          "valueOf");
+          "valueOf",
+          "ZERO");

  /** Instantiates a new {@link NonStaticImport} instance. */
  public NonStaticImport() {}
@@ -172,9 +168,10 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
        ImmutableTable.builder();
    for (ImportTree importTree : tree.getImports()) {
      Tree qualifiedIdentifier = importTree.getQualifiedIdentifier();
-      if (importTree.isStatic() && qualifiedIdentifier instanceof MemberSelectTree memberSelect) {
-        String type = SourceCode.treeToString(memberSelect.getExpression(), state);
-        String member = memberSelect.getIdentifier().toString();
+      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,
@@ -185,7 +182,7 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
      }
    }

-    return imports.buildOrThrow();
+    return imports.build();
  }

  private static boolean shouldNotBeStaticallyImported(String type, String member) {
@@ -213,7 +210,7 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
          }
        }

-        return super.visitIdentifier(node, null);
+        return super.visitIdentifier(node, unused);
      }
    }.scan(tree, null);
  }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/OptionalOrElseGet.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/OptionalOrElseGet.java
@@ -1,123 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.errorprone.BugPattern.LinkType.NONE;
-import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
-import static com.google.errorprone.BugPattern.StandardTags.PERFORMANCE;
-import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static java.util.stream.Collectors.joining;
-
-import com.google.auto.service.AutoService;
-import com.google.common.collect.Iterables;
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.bugpatterns.BugChecker;
-import com.google.errorprone.bugpatterns.BugChecker.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.refaster.Refaster;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.MemberSelectTree;
-import com.sun.source.tree.MethodInvocationTree;
-import java.util.Optional;
-import java.util.function.Supplier;
-import tech.picnic.errorprone.refaster.matchers.RequiresComputation;
-import tech.picnic.errorprone.utils.SourceCode;
-
-/**
- * A {@link BugChecker} that flags arguments to {@link Optional#orElse(Object)} that should be
- * deferred using {@link Optional#orElseGet(Supplier)}.
- *
- * <p>The suggested fix assumes that the argument to {@code orElse} does not have side effects. If
- * it does, the suggested fix changes the program's semantics. Such fragile code must instead be
- * refactored such that the side-effectful code does not appear accidental.
- */
-// XXX: This rule may introduce a compilation error: the `value` expression may reference a
-// non-effectively final variable, which is not allowed in the replacement lambda expression.
-// Review whether a `@Matcher` can be used to avoid this.
-// XXX: Once the `MethodReferenceUsageCheck` bug checker becomes generally usable, consider leaving
-// the method reference cleanup to that check, and express the remainder of the logic in this class
-// using a Refaster template, i.c.w. a `@NotMatches(RequiresComputation.class)` constraint.
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary =
-        """
-        Prefer `Optional#orElseGet` over `Optional#orElse` if the fallback requires additional \
-        computation""",
-    linkType = NONE,
-    severity = WARNING,
-    tags = PERFORMANCE)
-public final class OptionalOrElseGet extends BugChecker implements MethodInvocationTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Matcher<ExpressionTree> REQUIRES_COMPUTATION = new RequiresComputation();
-  private static final Matcher<ExpressionTree> OPTIONAL_OR_ELSE_METHOD =
-      instanceMethod().onExactClass(Optional.class.getCanonicalName()).namedAnyOf("orElse");
-  // XXX: Also exclude invocations of `@Placeholder`-annotated methods.
-  private static final Matcher<ExpressionTree> REFASTER_METHOD =
-      staticMethod().onClass(Refaster.class.getCanonicalName());
-
-  /** Instantiates a new {@link OptionalOrElseGet} instance. */
-  public OptionalOrElseGet() {}
-
-  @Override
-  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    if (!OPTIONAL_OR_ELSE_METHOD.matches(tree, state)) {
-      return Description.NO_MATCH;
-    }
-
-    ExpressionTree argument = Iterables.getOnlyElement(tree.getArguments());
-    if (!REQUIRES_COMPUTATION.matches(argument, state)
-        || REFASTER_METHOD.matches(argument, state)) {
-      return Description.NO_MATCH;
-    }
-
-    /*
-     * We have a match. Construct the method reference or lambda expression to be passed to the
-     * replacement `#orElseGet` invocation.
-     */
-    String newArgument =
-        tryMethodReferenceConversion(argument, state)
-            .orElseGet(() -> "() -> " + SourceCode.treeToString(argument, state));
-
-    /* Construct the suggested fix, replacing the method invocation and its argument. */
-    SuggestedFix fix =
-        SuggestedFix.builder()
-            .merge(SuggestedFixes.renameMethodInvocation(tree, "orElseGet", state))
-            .replace(argument, newArgument)
-            .build();
-
-    return describeMatch(tree, fix);
-  }
-
-  /** Returns the nullary method reference matching the given expression, if any. */
-  private static Optional<String> tryMethodReferenceConversion(
-      ExpressionTree tree, VisitorState state) {
-    if (!(tree instanceof MethodInvocationTree methodInvocation)) {
-      return Optional.empty();
-    }
-
-    if (!methodInvocation.getArguments().isEmpty()) {
-      return Optional.empty();
-    }
-
-    if (!(methodInvocation.getMethodSelect() instanceof MemberSelectTree memberSelect)) {
-      return Optional.empty();
-    }
-
-    if (REQUIRES_COMPUTATION.matches(memberSelect.getExpression(), state)) {
-      return Optional.empty();
-    }
-
-    return Optional.of(
-        SourceCode.treeToString(memberSelect.getExpression(), state)
-            + "::"
-            + (methodInvocation.getTypeArguments().isEmpty()
-                ? ""
-                : methodInvocation.getTypeArguments().stream()
-                    .map(arg -> SourceCode.treeToString(arg, state))
-                    .collect(joining(",", "<", ">")))
-            + memberSelect.getIdentifier());
-  }
-}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/PrimitiveComparison.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
@@ -22,7 +22,6 @@ 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.IdentifierTree;
 import com.sun.source.tree.LambdaExpressionTree;
 import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.MethodInvocationTree;
@@ -34,7 +33,7 @@ import java.util.Comparator;
 import java.util.Optional;
 import java.util.function.Function;
 import java.util.stream.Stream;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags {@code Comparator#comparing*} invocations that can be replaced
@@ -45,9 +44,8 @@ import tech.picnic.errorprone.utils.SourceCode;
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        Ensure invocations of `Comparator#comparing{,Double,Int,Long}` match the return type of \
-        the provided function""",
+        "Ensure invocations of `Comparator#comparing{,Double,Int,Long}` match the return type"
+            + " of the provided function",
    link = BUG_PATTERNS_BASE_URL + "PrimitiveComparison",
    linkType = CUSTOM,
    severity = WARNING,
@@ -149,44 +147,38 @@ public final class PrimitiveComparison extends BugChecker implements MethodInvoc
    return isStatic ? "comparing" : "thenComparing";
  }

-  // XXX: Use switch pattern matching once the targeted JDK supports this.
  private static Optional<Type> getPotentiallyBoxedReturnType(ExpressionTree tree) {
-    if (tree instanceof LambdaExpressionTree lambdaExpression) {
-      /* Return the lambda expression's actual return type. */
-      return Optional.ofNullable(ASTHelpers.getType(lambdaExpression.getBody()));
+    switch (tree.getKind()) {
+      case LAMBDA_EXPRESSION:
+        /* Return the lambda expression's actual return type. */
+        return Optional.ofNullable(ASTHelpers.getType(((LambdaExpressionTree) tree).getBody()));
+      case MEMBER_REFERENCE:
+        /* Return the method's declared return type. */
+        // XXX: Very fragile. Do better.
+        Type subType2 = ((JCMemberReference) tree).referentType;
+        return Optional.of(subType2.getReturnType());
+      default:
+        /* This appears to be a genuine `{,ToInt,ToLong,ToDouble}Function`. */
+        return Optional.empty();
    }
-
-    // XXX: The match against a concrete type and reference to one of its fields is fragile. Do
-    // better.
-    if (tree instanceof JCMemberReference memberReference) {
-      /* Return the method's declared return type. */
-      Type subType = memberReference.referentType;
-      return Optional.of(subType.getReturnType());
-    }
-
-    /* This appears to be a genuine `{,ToInt,ToLong,ToDouble}Function`. */
-    return Optional.empty();
  }

-  // XXX: Use switch pattern matching once the targeted JDK supports this.
  private static Fix suggestFix(
      MethodInvocationTree tree, String preferredMethodName, VisitorState state) {
    ExpressionTree expr = tree.getMethodSelect();
-
-    if (expr instanceof IdentifierTree) {
-      SuggestedFix.Builder fix = SuggestedFix.builder();
-      String replacement =
-          SuggestedFixes.qualifyStaticImport(
-              Comparator.class.getCanonicalName() + '.' + preferredMethodName, fix, state);
-      return fix.replace(expr, replacement).build();
+    switch (expr.getKind()) {
+      case IDENTIFIER:
+        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(
+            ms, SourceCode.treeToString(ms.getExpression(), state) + '.' + preferredMethodName);
+      default:
+        throw new VerifyException("Unexpected type of expression: " + expr.getKind());
    }
-
-    if (expr instanceof MemberSelectTree memberSelect) {
-      return SuggestedFix.replace(
-          memberSelect,
-          SourceCode.treeToString(memberSelect.getExpression(), state) + '.' + preferredMethodName);
-    }
-
-    throw new VerifyException("Unexpected type of expression: " + expr.getKind());
  }
 }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java
@@ -15,7 +15,7 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.Preconditions;
@@ -53,9 +53,9 @@ import java.util.Objects;
 import java.util.Optional;
 import java.util.stream.Stream;
 import javax.inject.Inject;
-import tech.picnic.errorprone.utils.Flags;
-import tech.picnic.errorprone.utils.MethodMatcherFactory;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.Flags;
+import tech.picnic.errorprone.bugpatterns.util.MethodMatcherFactory;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /** A {@link BugChecker} that flags redundant explicit string conversions. */
@AutoService(BugChecker.class)
@@ -331,32 +331,36 @@ public final class RedundantStringConversion extends BugChecker
  }

  private Optional<ExpressionTree> trySimplify(ExpressionTree tree, VisitorState state) {
-    if (!(tree instanceof MethodInvocationTree methodInvocation)) {
+    if (tree.getKind() != Kind.METHOD_INVOCATION) {
      return Optional.empty();
    }

+    MethodInvocationTree methodInvocation = (MethodInvocationTree) tree;
    if (!conversionMethodMatcher.matches(methodInvocation, state)) {
      return Optional.empty();
    }

-    return switch (methodInvocation.getArguments().size()) {
-      case 0 -> trySimplifyNullaryMethod(methodInvocation, state);
-      case 1 -> trySimplifyUnaryMethod(methodInvocation, state);
-      default ->
-          throw new IllegalStateException(
-              "Cannot simplify method call with two or more arguments: "
-                  + SourceCode.treeToString(tree, state));
-    };
+    switch (methodInvocation.getArguments().size()) {
+      case 0:
+        return trySimplifyNullaryMethod(methodInvocation, state);
+      case 1:
+        return trySimplifyUnaryMethod(methodInvocation, state);
+      default:
+        throw new IllegalStateException(
+            "Cannot simplify method call with two or more arguments: "
+                + SourceCode.treeToString(tree, state));
+    }
  }

  private static Optional<ExpressionTree> trySimplifyNullaryMethod(
      MethodInvocationTree methodInvocation, VisitorState state) {
-    if (!instanceMethod().matches(methodInvocation, state)
-        || !(methodInvocation.getMethodSelect() instanceof MemberSelectTree memberSelect)) {
+    if (!instanceMethod().matches(methodInvocation, state)) {
      return Optional.empty();
    }

-    return Optional.of(memberSelect.getExpression())
+    return Optional.of(methodInvocation.getMethodSelect())
+        .filter(methodSelect -> methodSelect.getKind() == Kind.MEMBER_SELECT)
+        .map(methodSelect -> ((MemberSelectTree) methodSelect).getExpression())
        .filter(expr -> !"super".equals(SourceCode.treeToString(expr, state)));
  }

@@ -378,11 +382,11 @@ public final class RedundantStringConversion extends BugChecker

  private static Matcher<MethodInvocationTree> createConversionMethodMatcher(
      ErrorProneFlags flags) {
-    // XXX: `Flags#getSet` splits by comma, but method signatures may also contain commas. For this
-    // class methods accepting more than one argument are not valid, but still: not nice.
+    // XXX: ErrorProneFlags#getList splits by comma, but method signatures may also contain commas.
+    // For this class methods accepting more than one argument are not valid, but still: not nice.
    return anyOf(
        WELL_KNOWN_STRING_CONVERSION_METHODS,
        new MethodMatcherFactory()
-            .create(Flags.getSet(flags, EXTRA_STRING_CONVERSION_METHODS_FLAG)));
+            .create(Flags.getList(flags, EXTRA_STRING_CONVERSION_METHODS_FLAG)));
  }
 }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringEscape.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringEscape.java
@@ -1,95 +0,0 @@
-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.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.LiteralTreeMatcher;
-import com.google.errorprone.fixes.SuggestedFix;
-import com.google.errorprone.matchers.Description;
-import com.google.errorprone.util.ASTHelpers;
-import com.sun.source.tree.LiteralTree;
-import tech.picnic.errorprone.utils.SourceCode;
-
-/** A {@link BugChecker} that flags string constants with extraneous escaping. */
-// XXX: Also cover `\"` sequences inside text blocks. Note that this requires a more subtle
-// approach, as double-quote characters will need to remain escaped if removing the backslash would
-// create a new sequence of three or more double-quotes. (TBD whether we'd like to enforce a
-// "preferred" approach to escaping, e.g. by always escaping the last of a triplet, such that the
-// over-all number of escaped characters is minimized.)
-// XXX: Also flag `'\"'` char literals.
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "Inside string expressions single quotes do not need to be escaped",
-    link = BUG_PATTERNS_BASE_URL + "RedundantStringEscape",
-    linkType = CUSTOM,
-    severity = SUGGESTION,
-    tags = SIMPLIFICATION)
-public final class RedundantStringEscape extends BugChecker implements LiteralTreeMatcher {
-  private static final long serialVersionUID = 1L;
-
-  /** Instantiates a new {@link RedundantStringEscape} instance. */
-  public RedundantStringEscape() {}
-
-  @Override
-  public Description matchLiteral(LiteralTree tree, VisitorState state) {
-    String constant = ASTHelpers.constValue(tree, String.class);
-    if (constant == null || constant.indexOf('\'') < 0) {
-      /* Fast path: this isn't a string constant with a single quote. */
-      return Description.NO_MATCH;
-    }
-
-    String source = SourceCode.treeToString(tree, state);
-    if (!containsBannedEscapeSequence(source)) {
-      /* Semi-fast path: this expression doesn't contain an escaped single quote. */
-      return Description.NO_MATCH;
-    }
-
-    /* Slow path: suggest dropping the escape characters. */
-    return describeMatch(tree, SuggestedFix.replace(tree, dropRedundantEscapeSequences(source)));
-  }
-
-  /**
-   * Tells whether the given string constant source expression contains an escaped single quote.
-   *
-   * @implNote As the input is a literal Java string expression, it will start and end with a double
-   *     quote; as such any found backslash will not be the string's final character.
-   */
-  private static boolean containsBannedEscapeSequence(String source) {
-    for (int p = source.indexOf('\\'); p != -1; p = source.indexOf('\\', p + 2)) {
-      if (source.charAt(p + 1) == '\'') {
-        return true;
-      }
-    }
-
-    return false;
-  }
-
-  /**
-   * Simplifies the given string constant source expression by dropping the backslash preceding an
-   * escaped single quote.
-   *
-   * @implNote Note that this method does not delegate to {@link
-   *     SourceCode#toStringConstantExpression}, as that operation may replace other Unicode
-   *     characters with their associated escape sequence.
-   * @implNote As the input is a literal Java string expression, it will start and end with a double
-   *     quote; as such any found backslash will not be the string's final character.
-   */
-  private static String dropRedundantEscapeSequences(String source) {
-    StringBuilder result = new StringBuilder();
-
-    for (int p = 0; p < source.length(); p++) {
-      char c = source.charAt(p);
-      if (c != '\\' || source.charAt(p + 1) != '\'') {
-        result.append(c);
-      }
-    }
-
-    return result.toString();
-  }
-}
--- a/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/RefasterAnyOfUsage.java
+++ b/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/RefasterAnyOfUsage.java
@@ -1,10 +1,10 @@
-package tech.picnic.errorprone.guidelines.bugpatterns;
+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.method.MethodMatchers.staticMethod;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -17,7 +17,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.refaster.Refaster;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags unnecessary {@link Refaster#anyOf(Object[])} usages.
@@ -42,18 +42,21 @@ public final class RefasterAnyOfUsage extends BugChecker implements MethodInvoca

  @Override
  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    int argumentCount = tree.getArguments().size();
-    if (argumentCount > 1 || !REFASTER_ANY_OF.matches(tree, state)) {
-      return Description.NO_MATCH;
+    if (REFASTER_ANY_OF.matches(tree, state)) {
+      switch (tree.getArguments().size()) {
+        case 0:
+          // We can't safely fix this case; dropping the expression may produce non-compilable code.
+          return describeMatch(tree);
+        case 1:
+          return describeMatch(
+              tree,
+              SuggestedFix.replace(
+                  tree, SourceCode.treeToString(tree.getArguments().get(0), state)));
+        default:
+          /* Handled below. */
+      }
    }

-    if (argumentCount == 0) {
-      /* We can't safely fix this case; dropping the expression may produce non-compilable code. */
-      return describeMatch(tree);
-    }
-
-    return describeMatch(
-        tree,
-        SuggestedFix.replace(tree, SourceCode.treeToString(tree.getArguments().get(0), state)));
+    return Description.NO_MATCH;
  }
 }
--- a/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/RefasterRuleModifiers.java
+++ b/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/RefasterRuleModifiers.java
@@ -1,11 +1,11 @@
-package tech.picnic.errorprone.guidelines.bugpatterns;
+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 com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.hasAnnotation;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestMappingAnnotation.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -73,9 +73,7 @@ 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"),
-                          isType(
-                              "org.springframework.security.core.annotation.CurrentSecurityContext"))),
+                          isType(ANN_PACKAGE_PREFIX + "RequestPart"))),
                  isSameType(InputStream.class.getCanonicalName()),
                  isSameType(Locale.class.getCanonicalName()),
                  isSameType(TimeZone.class.getCanonicalName()),
@@ -105,10 +103,9 @@ 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;
  }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamType.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamType.java
@@ -11,12 +11,12 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
@@ -28,15 +28,13 @@ import com.google.errorprone.suppliers.Suppliers;
 import com.sun.source.tree.Tree;
 import com.sun.source.tree.VariableTree;
 import javax.inject.Inject;
-import tech.picnic.errorprone.utils.Flags;
+import tech.picnic.errorprone.bugpatterns.util.Flags;

 /** A {@link BugChecker} that flags {@code @RequestParam} parameters with an unsupported type. */
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        By default, `@RequestParam` does not support `ImmutableCollection` and `ImmutableMap` \
-        subtypes""",
+        "By default, `@RequestParam` does not support `ImmutableCollection` and `ImmutableMap` subtypes",
    link = BUG_PATTERNS_BASE_URL + "RequestParamType",
    linkType = CUSTOM,
    severity = ERROR,
@@ -74,10 +72,10 @@ public final class RequestParamType extends BugChecker implements VariableTreeMa
    return allOf(
        annotations(AT_LEAST_ONE, isType("org.springframework.web.bind.annotation.RequestParam")),
        anyOf(isSubtypeOf(ImmutableCollection.class), isSubtypeOf(ImmutableMap.class)),
-        not(isSubtypeOfAny(Flags.getSet(flags, SUPPORTED_CUSTOM_TYPES_FLAG))));
+        not(isSubtypeOfAny(Flags.getList(flags, SUPPORTED_CUSTOM_TYPES_FLAG))));
  }

-  private static Matcher<Tree> isSubtypeOfAny(ImmutableSet<String> inclusions) {
+  private static Matcher<Tree> isSubtypeOfAny(ImmutableList<String> inclusions) {
    return anyOf(
        inclusions.stream()
            .map(inclusion -> isSubtypeOf(Suppliers.typeFromString(inclusion)))
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/Slf4jLogStatement.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
@@ -23,11 +23,13 @@ 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.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.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
 // https://www.slf4j.org/faq.html#paramException. That should be documented.
+// XXX: Also simplify `LOG.error(String.format("Something %s", arg), throwable)`.
+// XXX: Also simplify `LOG.error(String.join("sep", arg1, arg2), throwable)`? Perhaps too obscure.
 // XXX: Write a similar checker for Spring RestTemplates, String.format and friends, Guava
 // preconditions, ...
@AutoService(BugChecker.class)
@@ -39,7 +41,7 @@ import tech.picnic.errorprone.utils.SourceCode;
    tags = LIKELY_ERROR)
 public final class Slf4jLogStatement extends BugChecker implements MethodInvocationTreeMatcher {
  private static final long serialVersionUID = 1L;
-  private static final Matcher<ExpressionTree> SLF4J_MARKER = isSubtypeOf("org.slf4j.Marker");
+  private static final Matcher<ExpressionTree> MARKER = isSubtypeOf("org.slf4j.Marker");
  private static final Matcher<ExpressionTree> THROWABLE = isSubtypeOf(Throwable.class);
  private static final Matcher<ExpressionTree> SLF4J_LOGGER_INVOCATION =
      instanceMethod()
@@ -69,7 +71,7 @@ public final class Slf4jLogStatement extends BugChecker implements MethodInvocat
     * SLF4J log statements may accept a "marker" as a first argument, before the format string.
     * We ignore such markers.
     */
-    int lTrim = SLF4J_MARKER.matches(args.get(0), state) ? 1 : 0;
+    int lTrim = MARKER.matches(args.get(0), state) ? 1 : 0;
    /*
     * SLF4J treats the final argument to a log statement specially if it is a `Throwabe`: it
     * will always choose to render the associated stacktrace, even if the argument has a
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/Slf4jLoggerDeclaration.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/Slf4jLoggerDeclaration.java
@@ -1,185 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.common.base.Verify.verify;
-import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
-import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
-import static com.google.errorprone.BugPattern.StandardTags.STYLE;
-import static com.google.errorprone.matchers.Matchers.allOf;
-import static com.google.errorprone.matchers.Matchers.classLiteral;
-import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static com.google.errorprone.matchers.Matchers.staticMethod;
-import static com.google.errorprone.matchers.Matchers.toType;
-import static java.util.Objects.requireNonNull;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
-
-import com.google.auto.service.AutoService;
-import com.google.common.base.CaseFormat;
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.Iterables;
-import com.google.common.collect.Sets;
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.ErrorProneFlags;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.bugpatterns.BugChecker;
-import com.google.errorprone.bugpatterns.BugChecker.VariableTreeMatcher;
-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.ClassTree;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.MethodInvocationTree;
-import com.sun.source.tree.ModifiersTree;
-import com.sun.source.tree.Tree.Kind;
-import com.sun.source.tree.VariableTree;
-import com.sun.tools.javac.code.Symbol;
-import java.util.EnumSet;
-import javax.inject.Inject;
-import javax.lang.model.element.Modifier;
-import tech.picnic.errorprone.utils.MoreASTHelpers;
-
-/** A {@link BugChecker} that flags non-canonical SLF4J logger declarations. */
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "SLF4J logger declarations should follow established best-practices",
-    link = BUG_PATTERNS_BASE_URL + "Slf4jLoggerDeclaration",
-    linkType = CUSTOM,
-    severity = WARNING,
-    tags = STYLE)
-@SuppressWarnings("java:S2160" /* Super class equality definition suffices. */)
-public final class Slf4jLoggerDeclaration extends BugChecker implements VariableTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Matcher<ExpressionTree> IS_GET_LOGGER =
-      staticMethod().onDescendantOf("org.slf4j.LoggerFactory").named("getLogger");
-  private static final String CANONICAL_STATIC_LOGGER_NAME_FLAG =
-      "Slf4jLoggerDeclaration:CanonicalStaticLoggerName";
-  private static final String DEFAULT_CANONICAL_LOGGER_NAME = "LOG";
-  private static final Matcher<ExpressionTree> IS_STATIC_ENCLOSING_CLASS_REFERENCE =
-      classLiteral(Slf4jLoggerDeclaration::isEnclosingClassReference);
-  private static final Matcher<ExpressionTree> IS_DYNAMIC_ENCLOSING_CLASS_REFERENCE =
-      toType(
-          MethodInvocationTree.class,
-          allOf(
-              instanceMethod().anyClass().named("getClass").withNoParameters(),
-              Slf4jLoggerDeclaration::getClassReceiverIsEnclosingClassInstance));
-  private static final ImmutableSet<Modifier> INSTANCE_DECLARATION_MODIFIERS =
-      Sets.immutableEnumSet(Modifier.PRIVATE, Modifier.FINAL);
-  private static final ImmutableSet<Modifier> STATIC_DECLARATION_MODIFIERS =
-      Sets.immutableEnumSet(Modifier.PRIVATE, Modifier.STATIC, Modifier.FINAL);
-
-  private final String canonicalStaticFieldName;
-  private final String canonicalInstanceFieldName;
-
-  /** Instantiates a default {@link Slf4jLoggerDeclaration} instance. */
-  public Slf4jLoggerDeclaration() {
-    this(ErrorProneFlags.empty());
-  }
-
-  /**
-   * Instantiates a customized {@link Slf4jLoggerDeclaration}.
-   *
-   * @param flags Any provided command line flags.
-   */
-  @Inject
-  Slf4jLoggerDeclaration(ErrorProneFlags flags) {
-    canonicalStaticFieldName =
-        flags.get(CANONICAL_STATIC_LOGGER_NAME_FLAG).orElse(DEFAULT_CANONICAL_LOGGER_NAME);
-    canonicalInstanceFieldName =
-        CaseFormat.UPPER_UNDERSCORE.to(CaseFormat.LOWER_CAMEL, canonicalStaticFieldName);
-  }
-
-  @Override
-  public Description matchVariable(VariableTree tree, VisitorState state) {
-    ExpressionTree initializer = tree.getInitializer();
-    if (!IS_GET_LOGGER.matches(initializer, state)) {
-      return Description.NO_MATCH;
-    }
-
-    ClassTree clazz = getEnclosingClass(state);
-    ExpressionTree factoryArg =
-        Iterables.getOnlyElement(((MethodInvocationTree) initializer).getArguments());
-
-    SuggestedFix.Builder fix = SuggestedFix.builder();
-
-    if (clazz.getModifiers().getFlags().contains(Modifier.ABSTRACT)
-        && IS_DYNAMIC_ENCLOSING_CLASS_REFERENCE.matches(factoryArg, state)) {
-      /*
-       * While generally we prefer `Logger` declarations to be static and named after their
-       * enclosing class, we allow one exception: loggers in abstract classes with a name derived
-       * from `getClass()`.
-       */
-      suggestModifiers(tree, INSTANCE_DECLARATION_MODIFIERS, fix, state);
-      suggestRename(tree, canonicalInstanceFieldName, fix, state);
-    } else {
-      suggestModifiers(
-          tree,
-          clazz.getKind() == Kind.INTERFACE ? ImmutableSet.of() : STATIC_DECLARATION_MODIFIERS,
-          fix,
-          state);
-      suggestRename(tree, canonicalStaticFieldName, fix, state);
-
-      if (!MoreASTHelpers.isStringTyped(factoryArg, state)
-          && !IS_STATIC_ENCLOSING_CLASS_REFERENCE.matches(factoryArg, state)) {
-        /*
-         * Loggers with a custom string name are generally "special", but those with a name derived
-         * from a class other than the one that encloses it are likely in error.
-         */
-        fix.merge(SuggestedFix.replace(factoryArg, clazz.getSimpleName() + ".class"));
-      }
-    }
-
-    return fix.isEmpty() ? Description.NO_MATCH : describeMatch(tree, fix.build());
-  }
-
-  private static void suggestModifiers(
-      VariableTree tree,
-      ImmutableSet<Modifier> modifiers,
-      SuggestedFix.Builder fixBuilder,
-      VisitorState state) {
-    ModifiersTree modifiersTree =
-        requireNonNull(ASTHelpers.getModifiers(tree), "`VariableTree` must have modifiers");
-    SuggestedFixes.addModifiers(tree, modifiersTree, state, modifiers).ifPresent(fixBuilder::merge);
-    SuggestedFixes.removeModifiers(
-            modifiersTree, state, Sets.difference(EnumSet.allOf(Modifier.class), modifiers))
-        .ifPresent(fixBuilder::merge);
-  }
-
-  private static void suggestRename(
-      VariableTree variableTree, String name, SuggestedFix.Builder fixBuilder, VisitorState state) {
-    if (!variableTree.getName().contentEquals(name)) {
-      fixBuilder.merge(SuggestedFixes.renameVariable(variableTree, name, state));
-    }
-  }
-
-  private static boolean isEnclosingClassReference(ExpressionTree tree, VisitorState state) {
-    return ASTHelpers.getSymbol(getEnclosingClass(state)).equals(ASTHelpers.getSymbol(tree));
-  }
-
-  private static boolean getClassReceiverIsEnclosingClassInstance(
-      MethodInvocationTree getClassInvocationTree, VisitorState state) {
-    ExpressionTree receiver = ASTHelpers.getReceiver(getClassInvocationTree);
-    if (receiver == null) {
-      /*
-       * Method invocations without an explicit receiver either involve static methods (possibly
-       * statically imported), or instance methods invoked on the enclosing class. As the given
-       * `getClassInvocationTree` is guaranteed to be a nullary `#getClass()` invocation, the latter
-       * must be the case.
-       */
-      return true;
-    }
-
-    Symbol symbol = ASTHelpers.getSymbol(receiver);
-    return symbol != null
-        && symbol.asType().tsym.equals(ASTHelpers.getSymbol(getEnclosingClass(state)));
-  }
-
-  private static ClassTree getEnclosingClass(VisitorState state) {
-    ClassTree clazz = state.findEnclosing(ClassTree.class);
-    // XXX: Review whether we should relax this constraint in the face of so-called anonymous
-    // classes. See
-    // https://docs.oracle.com/en/java/javase/23/language/implicitly-declared-classes-and-instance-main-methods.html
-    verify(clazz != null, "Variable not defined inside class");
-    return clazz;
-  }
-}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/SpringMvcAnnotation.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/SpringMvcAnnotation.java
@@ -1,11 +1,12 @@
 package tech.picnic.errorprone.bugpatterns;

+import static com.google.common.base.Verify.verify;
 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 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.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.VerifyException;
@@ -24,9 +25,10 @@ import com.sun.source.tree.AssignmentTree;
 import com.sun.source.tree.ExpressionTree;
 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.utils.AnnotationAttributeMatcher;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags {@code @RequestMapping} annotations that can be written more
@@ -54,7 +56,7 @@ public final class SpringMvcAnnotation extends BugChecker implements AnnotationT
          .put("PATCH", "PatchMapping")
          .put("POST", "PostMapping")
          .put("PUT", "PutMapping")
-          .buildOrThrow();
+          .build();

  /** Instantiates a new {@link SpringMvcAnnotation} instance. */
  public SpringMvcAnnotation() {}
@@ -78,25 +80,31 @@ public final class SpringMvcAnnotation extends BugChecker implements AnnotationT
  }

  private static Optional<String> extractUniqueMethod(ExpressionTree arg, VisitorState state) {
-    if (!(arg instanceof AssignmentTree assignment)) {
-      throw new VerifyException("Annotation attribute is not an assignment:" + arg.getKind());
+    verify(
+        arg.getKind() == Kind.ASSIGNMENT,
+        "Annotation attribute is not an assignment: %s",
+        arg.getKind());
+
+    ExpressionTree expr = ((AssignmentTree) arg).getExpression();
+    if (expr.getKind() != Kind.NEW_ARRAY) {
+      return Optional.of(extractMethod(expr, state));
    }

-    ExpressionTree expr = assignment.getExpression();
-    return expr instanceof NewArrayTree newArray
-        ? Optional.of(newArray.getInitializers())
-            .filter(args -> args.size() == 1)
-            .map(args -> extractMethod(args.get(0), state))
-        : Optional.of(extractMethod(expr, state));
+    NewArrayTree newArray = (NewArrayTree) expr;
+    return Optional.of(newArray.getInitializers())
+        .filter(args -> args.size() == 1)
+        .map(args -> extractMethod(args.get(0), state));
  }

-  // XXX: Use switch pattern matching once the targeted JDK supports this.
  private static String extractMethod(ExpressionTree expr, VisitorState state) {
-    return switch (expr.getKind()) {
-      case IDENTIFIER -> SourceCode.treeToString(expr, state);
-      case MEMBER_SELECT -> ((MemberSelectTree) expr).getIdentifier().toString();
-      default -> throw new VerifyException("Unexpected type of expression: " + expr.getKind());
-    };
+    switch (expr.getKind()) {
+      case IDENTIFIER:
+        return SourceCode.treeToString(expr, state);
+      case MEMBER_SELECT:
+        return ((MemberSelectTree) expr).getIdentifier().toString();
+      default:
+        throw new VerifyException("Unexpected type of expression: " + expr.getKind());
+    }
  }

  private static Fix replaceAnnotation(
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StaticImport.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StaticImport.java
@@ -6,7 +6,7 @@ import static com.google.errorprone.BugPattern.StandardTags.STYLE;
 import static java.util.Objects.requireNonNull;
 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 static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.annotations.VisibleForTesting;
@@ -39,13 +39,11 @@ 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.predicates.TypePredicates;
 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.source.tree.Tree.Kind;
 import com.sun.tools.javac.code.Type;
 import java.nio.charset.StandardCharsets;
 import java.time.ZoneOffset;
@@ -102,7 +100,6 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
          Preconditions.class.getCanonicalName(),
          Predicates.class.getCanonicalName(),
          StandardCharsets.class.getCanonicalName(),
-          TypePredicates.class.getCanonicalName(),
          Verify.class.getCanonicalName(),
          "com.fasterxml.jackson.annotation.JsonCreator.Mode",
          "com.fasterxml.jackson.annotation.JsonFormat.Shape",
@@ -135,7 +132,7 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
          "org.springframework.http.MediaType",
          "org.testng.Assert",
          "reactor.function.TupleUtils",
-          "tech.picnic.errorprone.utils.MoreTypes");
+          "tech.picnic.errorprone.bugpatterns.util.MoreTypes");

  /**
   * Type members that should be statically imported.
@@ -212,10 +209,15 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
    Tree parentTree =
        requireNonNull(state.getPath().getParentPath(), "MemberSelectTree lacks enclosing node")
            .getLeaf();
-
-    return parentTree instanceof MethodInvocationTree methodInvocation
-        ? methodInvocation.getTypeArguments().isEmpty()
-        : (parentTree.getKind() != Kind.IMPORT && parentTree.getKind() != Kind.MEMBER_SELECT);
+    switch (parentTree.getKind()) {
+      case IMPORT:
+      case MEMBER_SELECT:
+        return false;
+      case METHOD_INVOCATION:
+        return ((MethodInvocationTree) parentTree).getTypeArguments().isEmpty();
+      default:
+        return true;
+    }
  }

  private static boolean isCandidate(MemberSelectTree tree) {
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StringJoin.java
+++ b/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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.common.base.Splitter;
@@ -23,11 +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.Constants;
 import java.util.Formattable;
 import java.util.Iterator;
 import java.util.List;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.utils.SourceCode;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;

 /**
 * A {@link BugChecker} that flags {@link String#format(String, Object...)} invocations which can be
@@ -36,9 +37,7 @@ import tech.picnic.errorprone.utils.SourceCode;
 */
 // XXX: What about `v1 + "sep" + v2` and similar expressions? Do we want to rewrite those to
 // `String.join`, or should some `String.join` invocations be rewritten to use the `+` operator?
-// (The latter suggestion would conflict with the `FormatStringConcatenation` check, but does make
-// more sense when `"sep"` is a long string. Similarly for `String.format("%s some long text %s",
-// arg1, arg2)`.)
+// (The latter suggestion would conflict with the `FormatStringConcatenation` check.)
@AutoService(BugChecker.class)
@BugPattern(
    summary = "Prefer `String#join` over `String#format`",
@@ -151,7 +150,7 @@ public final class StringJoin extends BugChecker implements MethodInvocationTree
    SuggestedFix.Builder fix =
        SuggestedFix.builder()
            .replace(tree.getMethodSelect(), "String.join")
-            .replace(arguments.next(), SourceCode.toStringConstantExpression(separator, state));
+            .replace(arguments.next(), Constants.format(separator));

    while (arguments.hasNext()) {
      ExpressionTree argument = arguments.next();
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/TimeZoneUsage.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/TimeZoneUsage.java
@@ -10,18 +10,16 @@ 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.utils.Documentation.BUG_PATTERNS_BASE_URL;
+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.MemberReferenceTreeMatcher;
 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.MemberReferenceTree;
 import com.sun.source.tree.MethodInvocationTree;
 import java.time.Clock;
 import java.time.Instant;
@@ -36,15 +34,12 @@ import java.time.ZonedDateTime;
@AutoService(BugChecker.class)
@BugPattern(
    summary =
-        """
-        Derive the current time from an existing `Clock` Spring bean, and don't rely on a \
-        `Clock`'s time zone""",
+        "Derive the current time from an existing `Clock` Spring bean, and don't rely on a `Clock`'s time zone",
    link = BUG_PATTERNS_BASE_URL + "TimeZoneUsage",
    linkType = CUSTOM,
    severity = WARNING,
    tags = FRAGILE_CODE)
-public final class TimeZoneUsage extends BugChecker
-    implements MethodInvocationTreeMatcher, MemberReferenceTreeMatcher {
+public final class TimeZoneUsage extends BugChecker implements MethodInvocationTreeMatcher {
  private static final long serialVersionUID = 1L;
  private static final Matcher<ExpressionTree> BANNED_TIME_METHOD =
      anyOf(
@@ -62,10 +57,6 @@ public final class TimeZoneUsage extends BugChecker
                  "tickMillis",
                  "tickMinutes",
                  "tickSeconds"),
-          staticMethod()
-              .onClassAny(Instant.class.getCanonicalName())
-              .named("now")
-              .withNoParameters(),
          staticMethod()
              .onClassAny(
                  LocalDate.class.getCanonicalName(),
@@ -74,22 +65,17 @@ public final class TimeZoneUsage extends BugChecker
                  OffsetDateTime.class.getCanonicalName(),
                  OffsetTime.class.getCanonicalName(),
                  ZonedDateTime.class.getCanonicalName())
-              .named("now"));
+              .named("now"),
+          staticMethod()
+              .onClassAny(Instant.class.getCanonicalName())
+              .named("now")
+              .withNoParameters());

  /** Instantiates a new {@link TimeZoneUsage} instance. */
  public TimeZoneUsage() {}

  @Override
  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    return getDescription(tree, state);
-  }
-
-  @Override
-  public Description matchMemberReference(MemberReferenceTree tree, VisitorState state) {
-    return getDescription(tree, state);
-  }
-
-  private Description getDescription(ExpressionTree tree, VisitorState state) {
    return BANNED_TIME_METHOD.matches(tree, state)
        ? buildDescription(tree).build()
        : Description.NO_MATCH;
--- a/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/UnqualifiedSuggestedFixImport.java
+++ b/error-prone-guidelines/src/main/java/tech/picnic/errorprone/guidelines/bugpatterns/UnqualifiedSuggestedFixImport.java
@@ -1,10 +1,10 @@
-package tech.picnic.errorprone.guidelines.bugpatterns;
+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.instanceMethod;
-import static tech.picnic.errorprone.utils.Documentation.BUG_PATTERNS_BASE_URL;
+import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;

 import com.google.auto.service.AutoService;
 import com.google.errorprone.BugPattern;
@@ -45,14 +45,16 @@ public final class UnqualifiedSuggestedFixImport extends BugChecker
      return Description.NO_MATCH;
    }

-    return switch (ASTHelpers.getSymbol(tree).getSimpleName().toString()) {
-      case "addImport" ->
-          createDescription(tree, "SuggestedFix.Builder#addImport", "SuggestedFixes#qualifyType");
-      case "addStaticImport" ->
-          createDescription(
-              tree, "SuggestedFix.Builder#addStaticImport", "SuggestedFixes#qualifyStaticImport");
-      default -> Description.NO_MATCH;
-    };
+    switch (ASTHelpers.getSymbol(tree).getSimpleName().toString()) {
+      case "addImport":
+        return createDescription(
+            tree, "SuggestedFix.Builder#addImport", "SuggestedFixes#qualifyType");
+      case "addStaticImport":
+        return createDescription(
+            tree, "SuggestedFix.Builder#addStaticImport", "SuggestedFixes#qualifyStaticImport");
+      default:
+        return Description.NO_MATCH;
+    }
  }

  private Description createDescription(
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/AnnotationAttributeMatcher.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/AnnotationAttributeMatcher.java
@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.utils;
+package tech.picnic.errorprone.bugpatterns.util;

 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.HashMultimap;
@@ -9,6 +9,7 @@ import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.AnnotationTree;
 import com.sun.source.tree.AssignmentTree;
 import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.Tree.Kind;
 import com.sun.tools.javac.code.Type;
 import java.io.Serializable;
 import java.util.HashSet;
@@ -115,8 +116,8 @@ public final class AnnotationAttributeMatcher implements Serializable {
  }

  private static String extractAttributeName(ExpressionTree expr) {
-    return (expr instanceof AssignmentTree assignment)
-        ? ASTHelpers.getSymbol(assignment.getVariable()).getSimpleName().toString()
+    return (expr.getKind() == Kind.ASSIGNMENT)
+        ? ASTHelpers.getSymbol(((AssignmentTree) expr).getVariable()).getSimpleName().toString()
        : "value";
  }

--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/ConflictDetection.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/ConflictDetection.java
@@ -0,0 +1,75 @@
+package tech.picnic.errorprone.bugpatterns.util;
+
+import static tech.picnic.errorprone.bugpatterns.util.JavaKeywords.isValidIdentifier;
+
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.ImportTree;
+import com.sun.source.tree.Tree;
+import com.sun.tools.javac.code.Symbol.MethodSymbol;
+import com.sun.tools.javac.code.Type;
+import java.util.Optional;
+
+/** A set of helper methods for detecting conflicts that would be caused when applying fixes. */
+public final class ConflictDetection {
+  private ConflictDetection() {}
+
+  /**
+   * 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 in its class or a supertype.
+   *   <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>
+   *
+   * @param method The method considered for renaming.
+   * @param newName The newly proposed name for the method.
+   * @param state The {@link VisitorState} to use when searching for blockers.
+   * @return A human-readable argument against assigning the proposed name to the given method, or
+   *     {@link Optional#empty()} if no blocker was found.
+   */
+  public 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());
+  }
+}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/Documentation.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/Documentation.java
@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.utils;
+package tech.picnic.errorprone.bugpatterns.util;

 /** Utility class providing documentation-related code. */
 public final class Documentation {
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/Flags.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/Flags.java
@@ -0,0 +1,22 @@
+package tech.picnic.errorprone.bugpatterns.util;
+
+import com.google.common.collect.ImmutableList;
+import com.google.errorprone.ErrorProneFlags;
+
+/** Helper methods for working with {@link ErrorProneFlags}. */
+public final class Flags {
+  private Flags() {}
+
+  /**
+   * Returns the list of (comma-separated) arguments passed using the given Error Prone flag.
+   *
+   * @param errorProneFlags The full set of flags provided.
+   * @param name The name of the flag of interest.
+   * @return A non-{@code null} list of provided arguments; this list is empty if the flag was not
+   *     provided, or if the flag's value is the empty string.
+   */
+  public static ImmutableList<String> getList(ErrorProneFlags errorProneFlags, String name) {
+    ImmutableList<String> list = errorProneFlags.getListOrEmpty(name);
+    return list.equals(ImmutableList.of("")) ? ImmutableList.of() : list;
+  }
+}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/JavaKeywords.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/JavaKeywords.java
@@ -0,0 +1,159 @@
+package tech.picnic.errorprone.bugpatterns.util;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+
+/** Utility class that can be used to identify reserved keywords of the Java language. */
+// XXX: This class is no longer only about keywords. Consider changing its name and class-level
+// documentation.
+public final class JavaKeywords {
+  /**
+   * Enumeration of boolean and null literals.
+   *
+   * @see <a href="https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.10.3">JDK 17
+   *     JLS section 3.10.3: Boolean Literals</a>
+   * @see <a href="https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.10.8">JDK 17
+   *     JLS section 3.10.8: The Null Literal</a>
+   */
+  private static final ImmutableSet<String> BOOLEAN_AND_NULL_LITERALS =
+      ImmutableSet.of("true", "false", "null");
+
+  /**
+   * List of all reserved keywords in the Java language.
+   *
+   * @see <a href="https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.9">JDK 17 JLS
+   *     section 3.9: Keywords</a>
+   */
+  private static final ImmutableSet<String> RESERVED_KEYWORDS =
+      ImmutableSet.of(
+          "_",
+          "abstract",
+          "assert",
+          "boolean",
+          "break",
+          "byte",
+          "case",
+          "catch",
+          "char",
+          "class",
+          "const",
+          "continue",
+          "default",
+          "do",
+          "double",
+          "else",
+          "enum",
+          "extends",
+          "final",
+          "finally",
+          "float",
+          "for",
+          "goto",
+          "if",
+          "implements",
+          "import",
+          "instanceof",
+          "int",
+          "interface",
+          "long",
+          "native",
+          "new",
+          "package",
+          "private",
+          "protected",
+          "public",
+          "return",
+          "short",
+          "static",
+          "strictfp",
+          "super",
+          "switch",
+          "synchronized",
+          "this",
+          "throw",
+          "throws",
+          "transient",
+          "try",
+          "void",
+          "volatile",
+          "while");
+
+  /**
+   * List of all contextual keywords in the Java language.
+   *
+   * @see <a href="https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.9">JDK 17 JLS
+   *     section 3.9: Keywords</a>
+   */
+  private static final ImmutableSet<String> CONTEXTUAL_KEYWORDS =
+      ImmutableSet.of(
+          "exports",
+          "module",
+          "non-sealed",
+          "open",
+          "opens",
+          "permits",
+          "provides",
+          "record",
+          "requires",
+          "sealed",
+          "to",
+          "transitive",
+          "uses",
+          "var",
+          "with",
+          "yield");
+
+  /** List of all keywords in the Java language. */
+  private static final ImmutableSet<String> ALL_KEYWORDS =
+      Sets.union(RESERVED_KEYWORDS, CONTEXTUAL_KEYWORDS).immutableCopy();
+
+  private JavaKeywords() {}
+
+  /**
+   * Tells whether the given string is a valid identifier in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a valid identifier in the Java language.
+   * @see <a href="https://docs.oracle.com/javase/specs/jls/se17/html/jls-3.html#jls-3.8">JDK 17 JLS
+   *     section 3.8: Identifiers</a>
+   */
+  @SuppressWarnings("java:S1067" /* Chaining conjunctions like this does not impact readability. */)
+  public static boolean isValidIdentifier(String str) {
+    return !str.isEmpty()
+        && !isReservedKeyword(str)
+        && !BOOLEAN_AND_NULL_LITERALS.contains(str)
+        && Character.isJavaIdentifierStart(str.codePointAt(0))
+        && str.codePoints().skip(1).allMatch(Character::isUnicodeIdentifierPart);
+  }
+
+  /**
+   * Tells whether the given string is a reserved keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a reserved keyword in the Java language.
+   */
+  public static boolean isReservedKeyword(String str) {
+    return RESERVED_KEYWORDS.contains(str);
+  }
+
+  /**
+   * Tells whether the given string is a contextual keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a contextual keyword in the Java language.
+   */
+  public static boolean isContextualKeyword(String str) {
+    return CONTEXTUAL_KEYWORDS.contains(str);
+  }
+
+  /**
+   * Tells whether the given string is a reserved or contextual keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a reserved or contextual keyword in the Java
+   *     language.
+   */
+  public static boolean isKeyword(String str) {
+    return ALL_KEYWORDS.contains(str);
+  }
+}
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MethodMatcherFactory.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MethodMatcherFactory.java
@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.utils;
+package tech.picnic.errorprone.bugpatterns.util;

 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
@@ -45,6 +45,9 @@ public final class MethodMatcherFactory {
  // XXX: It seems parse errors are silently swallowed. Double-check; if true, file a ticket.
  // XXX: This (probably) doesn't work for methods with array type arguments; if true, implement a
  // fix.
+  // XXX: The `nullness` warning suppression shouldn't be necessary. See
+  // https://github.com/typetools/checker-framework/issues/4006.
+  @SuppressWarnings("nullness:argument")
  private static Matcher<ExpressionTree> createMethodMatcher(CharSequence signature) {
    java.util.regex.Matcher m = METHOD_SIGNATURE.matcher(signature);
    checkArgument(m.matches(), "Not a valid method signature: %s", signature);
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MoreASTHelpers.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MoreASTHelpers.java
@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.utils;
+package tech.picnic.errorprone.bugpatterns.util;

 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.collect.ImmutableList.toImmutableList;
@@ -15,7 +15,8 @@ import java.util.Optional;
 /**
 * A collection of helper methods for working with the AST.
 *
- * <p>These methods are additions to the ones found in {@link ASTHelpers}.
+ * <p>These methods are additions to the ones found in {@link
+ * com.google.errorprone.util.ASTHelpers}.
 */
 public final class MoreASTHelpers {
  private MoreASTHelpers() {}
@@ -78,16 +79,4 @@ public final class MoreASTHelpers {
  public static boolean areSameType(Tree treeA, Tree treeB, VisitorState state) {
    return ASTHelpers.isSameType(ASTHelpers.getType(treeA), ASTHelpers.getType(treeB), state);
  }
-
-  /**
-   * Tells whether the given tree is of type {@link String}.
-   *
-   * @param tree The tree of interest.
-   * @param state The {@link VisitorState} describing the context in which the given tree was found.
-   * @return Whether the specified tree has the same type as {@link
-   *     com.sun.tools.javac.code.Symtab#stringType}.
-   */
-  public static boolean isStringTyped(Tree tree, VisitorState state) {
-    return ASTHelpers.isSameType(ASTHelpers.getType(tree), state.getSymtab().stringType, state);
-  }
 }
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MoreJUnitMatchers.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/util/MoreJUnitMatchers.java
@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.utils;
+package tech.picnic.errorprone.bugpatterns.util;

 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.errorprone.matchers.ChildMultiMatcher.MatchType.AT_LEAST_ONE;
@@ -6,7 +6,7 @@ import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.isType;
 import static java.util.Objects.requireNonNullElse;
-import static tech.picnic.errorprone.utils.MoreMatchers.hasMetaAnnotation;
+import static tech.picnic.errorprone.bugpatterns.util.MoreMatchers.hasMetaAnnotation;

 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
@@ -99,13 +99,14 @@ public final class MoreJUnitMatchers {
    String methodName = method.getName().toString();
    ExpressionTree value = AnnotationMatcherUtils.getArgument(methodSourceAnnotation, "value");

-    if (!(value instanceof NewArrayTree newArray)) {
+    if (!(value instanceof NewArrayTree)) {
      return ImmutableList.of(toMethodSourceFactoryDescriptor(value, methodName));
    }

-    return newArray.getInitializers().stream()
-        .map(name -> toMethodSourceFactoryDescriptor(name, methodName))
-        .collect(toImmutableList());
+    return ((NewArrayTree) value)
+        .getInitializers().stream()
+            .map(name -> toMethodSourceFactoryDescriptor(name, methodName))
+            .collect(toImmutableList());
  }

  private static String toMethodSourceFactoryDescriptor(
--- a/Show More
+++ b/Show More