Introduce StringFormat Refaster rule

XXX: Requires dropping JDK 11 support, or a means of filtering by target
language level.

.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. `17.0.8`).
-- Error Prone version (e.g. `2.18.0`).
-- Error Prone Support version (e.g. `0.9.0`).
+- 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`).
 
 ### Additional context
 

.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"

.github/workflows/build.yml

@@ -9,33 +9,44 @@ jobs:
   build:
     strategy:
       matrix:
-        os: [ ubuntu-22.04 ]
-        jdk: [ 11.0.20, 17.0.8, 21.0.0 ]
+        os: [ ubuntu-24.04 ]
+        jdk: [ 17.0.13, 21.0.5, 23.0.1 ]
         distribution: [ temurin ]
         experimental: [ false ]
         include:
           - os: macos-14
-            jdk: 17.0.8
+            jdk: 17.0.13
             distribution: temurin
             experimental: false
           - os: windows-2022
-            jdk: 17.0.8
+            jdk: 17.0.13
             distribution: temurin
             experimental: false
     runs-on: ${{ matrix.os }}
     continue-on-error: ${{ matrix.experimental }}
     steps:
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        with:
+          disable-sudo: true
+          egress-policy: block
+          allowed-endpoints: >
+            api.adoptium.net:443
+            github.com:443
+            jitpack.io: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@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+        uses: s4u/setup-maven-action@9a27433d289dd99d73851f653607c39d3444e8ba # v1.17.0
         with:
           java-version: ${{ matrix.jdk }}
           java-distribution: ${{ matrix.distribution }}
-          maven-version: 3.9.6
+          maven-version: 3.9.9
       - name: Display build environment details
         run: mvn --version
       - name: Build project against vanilla Error Prone, compile Javadoc
@@ -43,6 +54,6 @@ jobs:
       - name: Build project with self-check against Error Prone fork
         run: mvn -T1C clean verify -Perror-prone-fork -Pnon-maven-central -Pself-check -s settings.xml
       - name: Remove installed project artifacts
-        run: mvn build-helper:remove-project-artifact
+        run: mvn dependency:purge-local-repository -DmanualInclude='${project.groupId}' -DresolutionFuzziness=groupId
 
 # XXX: Enable Codecov once we "go public".

.github/workflows/codeql.yml

@@ -19,22 +19,34 @@ jobs:
     permissions:
       contents: read
       security-events: write
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
-      - name: Check out code and set up JDK and Maven
-        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
         with:
-          java-version: 17.0.8
+          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@9a27433d289dd99d73851f653607c39d3444e8ba # v1.17.0
+        with:
+          java-version: 17.0.13
           java-distribution: temurin
-          maven-version: 3.9.6
+          maven-version: 3.9.9
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
+        uses: github/codeql-action/init@f09c1c0a94de965c15400f5634aa42fac8fb8f88 # v3.27.5
         with:
           languages: ${{ matrix.language }}
       - name: Perform minimal build
         if: matrix.language == 'java'
         run: mvn -T1C clean package -DskipTests -Dverification.skip
       - name: Perform CodeQL analysis
-        uses: github/codeql-action/analyze@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
+        uses: github/codeql-action/analyze@f09c1c0a94de965c15400f5634aa42fac8fb8f88 # v3.27.5
         with:
           category: /language:${{ matrix.language }}

.github/workflows/deploy-website.yml

@@ -9,18 +9,45 @@ concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}
 jobs:
   build:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        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
+            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@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
-      - uses: ruby/setup-ruby@bd03e04863f52d169e18a2b190e8fa6b84938215 # v1.170.0
+      - uses: ruby/setup-ruby@a2bbe5b1b236842c1cb7dd11e8e3b51e0a616acc # v1.202.0
         with:
           working-directory: ./website
           bundler-cache: true
       - name: Configure Github Pages
-        uses: actions/configure-pages@1f0c5cde4bc74cd7e1254d0cb4de8d49e9068c7d # v4.0.0
+        uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5.0.0
       - name: Generate documentation
         run: ./generate-docs.sh
       - name: Build website with Jekyll
@@ -41,11 +68,18 @@ jobs:
     permissions:
       id-token: write
       pages: write
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     environment:
       name: github-pages
       url: ${{ steps.deployment.outputs.page_url }}
     steps:
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        with:
+          disable-sudo: true
+          egress-policy: block
+          allowed-endpoints: >
+            api.github.com:443
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@decdde0ac072f6dcbe43649d82d9c635fff5b4e4 # v4.0.4
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4.0.5

.github/workflows/openssf-scorecard.yml

@@ -18,19 +18,36 @@ jobs:
       contents: read
       security-events: write
       id-token: write
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        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@b4ffde65f46336ab88eb53be808477a3936bae11 # v4.1.1
+        uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
         with:
           persist-credentials: false
       - name: Run OpenSSF Scorecard analysis
-        uses: ossf/scorecard-action@0864cf19026789058feabb7e87baa5f140aac736 # v2.3.1
+        uses: ossf/scorecard-action@62b2cac7ed8198b15735ed49ab1e5cf35480ba46 # v2.4.0
         with:
           results_file: results.sarif
           results_format: sarif
           publish_results: ${{ github.ref == 'refs/heads/master' }}
       - name: Update GitHub's code scanning dashboard
-        uses: github/codeql-action/upload-sarif@b7bf0a3ed3ecfa44160715d7c442788f65f0f923 # v3.23.2
+        uses: github/codeql-action/upload-sarif@f09c1c0a94de965c15400f5634aa42fac8fb8f88 # v3.27.5
         with:
           sarif_file: results.sarif

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

@@ -9,15 +9,25 @@ permissions:
   contents: read
 jobs:
   analyze-pr:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        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@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+        uses: s4u/setup-maven-action@9a27433d289dd99d73851f653607c39d3444e8ba # v1.17.0
         with:
           checkout-fetch-depth: 2
-          java-version: 17.0.8
+          java-version: 17.0.13
           java-distribution: temurin
-          maven-version: 3.9.6
+          maven-version: 3.9.9
       - name: Run Pitest
         # By running with features `+GIT(from[HEAD~1]), +gitci`, Pitest only
         # analyzes lines changed in the associated pull request, as GitHub
@@ -28,7 +38,7 @@ 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@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4.3.1
+        uses: actions/upload-artifact@6f51ac03b9356f520e9adb1b1b7802705f340c2b # v4.5.0
         with:
           name: pitest-reports
           path: ./target/pit-reports-ci

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

@@ -17,16 +17,27 @@ jobs:
       checks: write
       contents: read
       pull-requests: write
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
-      - name: Check out code and set up JDK and Maven
-        uses: s4u/setup-maven-action@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
         with:
-          java-version: 17.0.8
+          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@9a27433d289dd99d73851f653607c39d3444e8ba # v1.17.0
+        with:
+          java-version: 17.0.13
           java-distribution: temurin
-          maven-version: 3.9.6
+          maven-version: 3.9.9
       - name: Download Pitest analysis artifact
-        uses: dawidd6/action-download-artifact@e7466d1a7587ed14867642c2ca74b5bcc1e19a2d # v3.0.0
+        uses: dawidd6/action-download-artifact@09f2f74827fd3a8607589e5ad7f9398816f540fe # v3.1.4
         with:
           workflow: ${{ github.event.workflow_run.workflow_id }}
           name: pitest-reports

.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: 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:
+# 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:
 # https://docs.github.com/en/actions/learn-github-actions/expressions#example-returning-a-json-object
 name: "Integration tests"
 on:
@@ -16,24 +16,48 @@ jobs:
     name: On-demand integration test
     if: |
       github.event.issue.pull_request && contains(github.event.comment.body, '/integration-test')
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
+    strategy:
+      matrix:
+        integration-test: [ "checkstyle", "metrics", "prometheus-java-client" ]
     steps:
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        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@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+        uses: s4u/setup-maven-action@9a27433d289dd99d73851f653607c39d3444e8ba # v1.17.0
         with:
           checkout-ref: "refs/pull/${{ github.event.issue.number }}/head"
-          java-version: 17.0.8
+          java-version: 17.0.13
           java-distribution: temurin
-          maven-version: 3.9.6
+          maven-version: 3.9.9
       - name: Install project to local Maven repository
         run: mvn -T1C install -DskipTests -Dverification.skip
       - name: Run integration test
-        run: xvfb-run ./integration-tests/checkstyle.sh "${{ runner.temp }}/artifacts"
+        run: xvfb-run "./integration-tests/${{ matrix.integration-test }}.sh" "${{ runner.temp }}/artifacts"
       - name: Upload artifacts on failure
         if: ${{ failure() }}
-        uses: actions/upload-artifact@5d5d22a31266ced268874388b861e4b58bb5c2f3 # v4.3.1
+        uses: actions/upload-artifact@6f51ac03b9356f520e9adb1b1b7802705f340c2b # v4.5.0
         with:
-          name: integration-test-checkstyle
+          name: "integration-test-${{ matrix.integration-test }}"
           path: "${{ runner.temp }}/artifacts"
       - name: Remove installed project artifacts
-        run: mvn build-helper:remove-project-artifact
+        run: mvn dependency:purge-local-repository -DmanualInclude='${project.groupId}' -DresolutionFuzziness=groupId

.github/workflows/sonarcloud.yml

@@ -13,18 +13,34 @@ jobs:
   analyze:
     # Analysis of code in forked repositories is skipped, as such workflow runs
     # do not have access to the requisite secrets.
-    if: github.event.pull_request.head.repo.full_name == github.repository
+    if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
     permissions:
       contents: read
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
     steps:
+      - name: Install Harden-Runner
+        uses: step-security/harden-runner@0080882f6c36860b6ba35c610c98ce87d4e2f26f # v2.10.2
+        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@fa2c7e4517ed008b1f73e7e0195a9eecf5582cd4 # v1.11.0
+        uses: s4u/setup-maven-action@9a27433d289dd99d73851f653607c39d3444e8ba # v1.17.0
         with:
           checkout-fetch-depth: 0
-          java-version: 17.0.8
+          java-version: 17.0.13
           java-distribution: temurin
-          maven-version: 3.9.6
+          maven-version: 3.9.9
       - name: Create missing `test` directory
         # XXX: Drop this step in favour of actually having a test.
         run: mkdir refaster-compiler/src/test

.gitignore

@@ -4,6 +4,7 @@
 .DS_Store
 .factorypath
 .idea
+!.idea/icon.svg
 .project
 .settings
 target

.idea/icon.svg

@@ -0,0 +1,65 @@
+<?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;">
+    <g transform="matrix(1,0,0,1,-624.154,-988.431)">
+        <g transform="matrix(1,0,0,1,-70.1122,-35.0561)">
+            <g transform="matrix(1,0,0,1,0,9.81959)">
+                <path d="M1227.03,1988.79C1237.78,2070.45 1225.83,2190.1 1192.24,2194.53C1158.65,2198.95 1116.14,2086.46 1105.39,2004.81C1094.64,1923.16 1128.44,1902.11 1153.32,1898.84C1178.18,1895.56 1216.28,1907.14 1227.03,1988.79Z" style="fill:rgb(219,220,211);fill-rule:nonzero;"/>
+            </g>
+            <g transform="matrix(1,0,0,1,0,9.81959)">
+                <path d="M1151.08,1881.86C1134.93,1883.99 1114.77,1892.69 1101.6,1913.17C1088.42,1933.64 1082.71,1963.73 1088.42,2007.04C1094.04,2049.75 1107.59,2099.16 1124.51,2138.68C1132.97,2158.45 1142.15,2175.68 1152.59,2188.86C1163.04,2202.05 1176.31,2213.89 1194.48,2211.5C1212.65,2209.11 1222.39,2194.23 1229.07,2178.8C1235.75,2163.36 1240.15,2144.34 1243.21,2123.05C1249.32,2080.5 1249.63,2029.27 1244,1986.56C1238.3,1943.24 1225,1915.66 1206.98,1899.29C1188.95,1882.93 1167.22,1879.74 1151.08,1881.86ZM1155.55,1915.81C1164.27,1914.66 1174.03,1915.62 1183.96,1924.64C1193.89,1933.66 1205.01,1952.69 1210.06,1991.03C1215.18,2029.97 1214.89,2079.4 1209.32,2118.19C1206.53,2137.58 1202.32,2154.4 1197.65,2165.2C1194.14,2173.29 1190.82,2176.3 1189.96,2177.22C1188.89,2176.55 1184.91,2174.51 1179.43,2167.6C1172.12,2158.38 1163.7,2143.22 1155.99,2125.21C1140.57,2089.18 1127.49,2041.51 1122.36,2002.57C1117.32,1964.24 1123.13,1942.97 1130.39,1931.69C1137.65,1920.42 1146.82,1916.96 1155.55,1915.81Z" style="fill:rgb(26,26,26);fill-rule:nonzero;"/>
+            </g>
+            <g transform="matrix(1,0,0,1,0,9.81959)">
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+            </g>
+            <g transform="matrix(1,0,0,1,0,9.81959)">
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+            </g>
+        </g>
+    </g>
+</svg>

.renovaterc.json

@@ -3,16 +3,30 @@
   "extends": [
     "helpers:pinGitHubActionDigests"
   ],
+  "customManagers": [
+    {
+      "customType": "regex",
+      "fileMatch": [
+        "^integration-tests/.*(-init\\.patch|\\.sh)$"
+      ],
+      "matchStrings": [
+        "\\b(?<packageName>[a-z0-9_.-]+?:[a-z0-9_.-]+?):(?<currentValue>[^:]+?):[a-zA-Z0-9_-]+\\b",
+        "<version>(?<currentValue>.*?)<!-- Renovate: (?<packageName>.*?) --></version>"
+      ],
+      "datasourceTemplate": "maven"
+    }
+  ],
   "packageRules": [
     {
-      "matchPackagePatterns": [
-        "^org\\.springframework:spring-framework-bom$",
-        "^org\\.springframework\\.boot:spring-boot[a-z-]*$"
+      "matchPackageNames": [
+        "/^org\\.springframework:spring-framework-bom$/",
+        "/^org\\.springframework\\.boot:spring-boot[a-z-]*$/"
       ],
       "separateMinorPatch": true
     },
     {
-      "matchDepNames": [
+      "matchPackageNames": [
+        "dawidd6/action-download-artifact",
         "github/codeql-action",
         "ruby/setup-ruby"
       ],

README.md

@@ -49,7 +49,9 @@ 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.
+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.
 
 #### Maven
 
@@ -215,7 +217,7 @@ 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 compatbility with Picnic's [Error Prone
+  where the second pass validates compatibility 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
@@ -263,6 +265,7 @@ 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
@@ -299,7 +302,7 @@ 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/badge/Reproducible_Builds-ok-success?labelColor=1e5b96
+[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-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

documentation-support/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.14.1-SNAPSHOT</version>
+        <version>0.19.2-SNAPSHOT</version>
     </parent>
 
     <artifactId>documentation-support</artifactId>
@@ -33,6 +33,15 @@
             <artifactId>error_prone_test_helpers</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>error-prone-utils</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>${project.groupId}</groupId>
+            <artifactId>refaster-test-support</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
             <artifactId>jackson-annotations</artifactId>

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

@@ -27,7 +27,7 @@ import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 import org.jspecify.annotations.Nullable;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCases;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.BugPatternTestCases;
 
 /**
  * An {@link Extractor} that describes how to extract data from classes that test a {@code
@@ -40,7 +40,7 @@ import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCases;
 @Immutable
 @AutoService(Extractor.class)
 @SuppressWarnings("rawtypes" /* See https://github.com/google/auto/issues/870. */)
-public final class BugPatternTestExtractor implements Extractor<TestCases> {
+public final class BugPatternTestExtractor implements Extractor<BugPatternTestCases> {
   /** Instantiates a new {@link BugPatternTestExtractor} instance. */
   public BugPatternTestExtractor() {}
 
@@ -50,7 +50,7 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
   }
 
   @Override
-  public Optional<TestCases> tryExtract(ClassTree tree, VisitorState state) {
+  public Optional<BugPatternTestCases> tryExtract(ClassTree tree, VisitorState state) {
     BugPatternTestCollector collector = new BugPatternTestCollector();
 
     collector.scan(tree, state);
@@ -59,7 +59,7 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
         .filter(not(ImmutableList::isEmpty))
         .map(
             tests ->
-                new AutoValue_BugPatternTestExtractor_TestCases(
+                new AutoValue_BugPatternTestExtractor_BugPatternTestCases(
                     state.getPath().getCompilationUnit().getSourceFile().toUri(),
                     ASTHelpers.getSymbol(tree).className(),
                     tests));
@@ -95,10 +95,10 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
             .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper.ExpectOutput")
             .namedAnyOf("addOutputLines", "expectUnchanged");
 
-    private final List<TestCase> collectedTestCases = new ArrayList<>();
+    private final List<BugPatternTestCase> collectedBugPatternTestCases = new ArrayList<>();
 
-    private ImmutableList<TestCase> getCollectedTests() {
-      return ImmutableList.copyOf(collectedTestCases);
+    private ImmutableList<BugPatternTestCase> getCollectedTests() {
+      return ImmutableList.copyOf(collectedBugPatternTestCases);
     }
 
     @Override
@@ -110,14 +110,14 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
                 classUnderTest -> {
                   List<TestEntry> entries = new ArrayList<>();
                   if (isReplacementTest) {
-                    extractReplacementTestCases(node, entries, state);
+                    extractReplacementBugPatternTestCases(node, entries, state);
                   } else {
-                    extractIdentificationTestCases(node, entries, state);
+                    extractIdentificationBugPatternTestCases(node, entries, state);
                   }
 
                   if (!entries.isEmpty()) {
-                    collectedTestCases.add(
-                        new AutoValue_BugPatternTestExtractor_TestCase(
+                    collectedBugPatternTestCases.add(
+                        new AutoValue_BugPatternTestExtractor_BugPatternTestCase(
                             classUnderTest, ImmutableList.copyOf(entries).reverse()));
                   }
                 });
@@ -135,12 +135,12 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
       }
 
       ExpressionTree receiver = ASTHelpers.getReceiver(tree);
-      return receiver instanceof MethodInvocationTree
-          ? getClassUnderTest((MethodInvocationTree) receiver, state)
+      return receiver instanceof MethodInvocationTree methodInvocation
+          ? getClassUnderTest(methodInvocation, state)
           : Optional.empty();
     }
 
-    private static void extractIdentificationTestCases(
+    private static void extractIdentificationBugPatternTestCases(
         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 +154,12 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
       }
 
       ExpressionTree receiver = ASTHelpers.getReceiver(tree);
-      if (receiver instanceof MethodInvocationTree) {
-        extractIdentificationTestCases((MethodInvocationTree) receiver, sink, state);
+      if (receiver instanceof MethodInvocationTree methodInvocation) {
+        extractIdentificationBugPatternTestCases(methodInvocation, sink, state);
       }
     }
 
-    private static void extractReplacementTestCases(
+    private static void extractReplacementBugPatternTestCases(
         MethodInvocationTree tree, List<TestEntry> sink, VisitorState state) {
       if (REPLACEMENT_OUTPUT_SOURCE_LINES.matches(tree, state)) {
         /*
@@ -184,8 +184,8 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
       }
 
       ExpressionTree receiver = ASTHelpers.getReceiver(tree);
-      if (receiver instanceof MethodInvocationTree) {
-        extractReplacementTestCases((MethodInvocationTree) receiver, sink, state);
+      if (receiver instanceof MethodInvocationTree methodInvocation) {
+        extractReplacementBugPatternTestCases(methodInvocation, sink, state);
       }
     }
 
@@ -208,24 +208,26 @@ public final class BugPatternTestExtractor implements Extractor<TestCases> {
   }
 
   @AutoValue
-  @JsonDeserialize(as = AutoValue_BugPatternTestExtractor_TestCases.class)
-  abstract static class TestCases {
-    static TestCases create(URI source, String testClass, ImmutableList<TestCase> testCases) {
-      return new AutoValue_BugPatternTestExtractor_TestCases(source, testClass, testCases);
+  @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 String testClass();
 
-    abstract ImmutableList<TestCase> testCases();
+    abstract ImmutableList<BugPatternTestCase> testCases();
   }
 
   @AutoValue
-  @JsonDeserialize(as = AutoValue_BugPatternTestExtractor_TestCase.class)
-  abstract static class TestCase {
-    static TestCase create(String classUnderTest, ImmutableList<TestEntry> entries) {
-      return new AutoValue_BugPatternTestExtractor_TestCase(classUnderTest, entries);
+  @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 String classUnderTest();

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

@@ -14,7 +14,6 @@ import java.io.IOException;
 import java.net.URI;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.util.ServiceLoader;
 import javax.tools.JavaFileObject;
 
@@ -87,6 +86,6 @@ final class DocumentationGeneratorTaskListener implements TaskListener {
   }
 
   private static String getSimpleClassName(URI path) {
-    return Paths.get(path).getFileName().toString().replace(".java", "");
+    return Path.of(path).getFileName().toString().replace(".java", "");
   }
 }

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

@@ -0,0 +1,176 @@
+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();
+  }
+}

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

@@ -7,10 +7,10 @@ import java.net.URI;
 import java.nio.file.Path;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.BugPatternTestCase;
+import tech.picnic.errorprone.documentation.BugPatternTestExtractor.BugPatternTestCases;
 import tech.picnic.errorprone.documentation.BugPatternTestExtractor.IdentificationTestEntry;
 import tech.picnic.errorprone.documentation.BugPatternTestExtractor.ReplacementTestEntry;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCase;
-import tech.picnic.errorprone.documentation.BugPatternTestExtractor.TestCases;
 
 final class BugPatternTestExtractorTest {
   @Test
@@ -269,11 +269,11 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "SingleFileCompilationTestHelperTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create("file:///SingleFileCompilationTestHelperTest.java"),
             "SingleFileCompilationTestHelperTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "SingleFileCompilationTestHelperTest.TestChecker",
                     ImmutableList.of(
                         IdentificationTestEntry.create(
@@ -302,11 +302,11 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "SingleFileCompilationTestHelperWithSetArgsTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create("file:///SingleFileCompilationTestHelperWithSetArgsTest.java"),
             "SingleFileCompilationTestHelperWithSetArgsTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "SingleFileCompilationTestHelperWithSetArgsTest.TestChecker",
                     ImmutableList.of(
                         IdentificationTestEntry.create(
@@ -335,11 +335,11 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "MultiFileCompilationTestHelperTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create("file:///MultiFileCompilationTestHelperTest.java"),
             "MultiFileCompilationTestHelperTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "MultiFileCompilationTestHelperTest.TestChecker",
                     ImmutableList.of(
                         IdentificationTestEntry.create(
@@ -370,11 +370,11 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "SingleFileBugCheckerRefactoringTestHelperTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create("file:///SingleFileBugCheckerRefactoringTestHelperTest.java"),
             "SingleFileBugCheckerRefactoringTestHelperTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "SingleFileBugCheckerRefactoringTestHelperTest.TestChecker",
                     ImmutableList.of(
                         ReplacementTestEntry.create(
@@ -408,12 +408,12 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create(
                 "file:///SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.java"),
             "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "SingleFileBugCheckerRefactoringTestHelperWithSetArgsFixChooserAndCustomTestModeTest.TestChecker",
                     ImmutableList.of(
                         ReplacementTestEntry.create(
@@ -444,11 +444,11 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "MultiFileBugCheckerRefactoringTestHelperTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create("file:///MultiFileBugCheckerRefactoringTestHelperTest.java"),
             "MultiFileBugCheckerRefactoringTestHelperTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "MultiFileBugCheckerRefactoringTestHelperTest.TestChecker",
                     ImmutableList.of(
                         ReplacementTestEntry.create(
@@ -484,16 +484,16 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "CompilationAndBugCheckerRefactoringTestHelpersTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create("file:///CompilationAndBugCheckerRefactoringTestHelpersTest.java"),
             "CompilationAndBugCheckerRefactoringTestHelpersTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
                     ImmutableList.of(
                         IdentificationTestEntry.create(
                             "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))),
-                TestCase.create(
+                BugPatternTestCase.create(
                     "CompilationAndBugCheckerRefactoringTestHelpersTest.TestChecker",
                     ImmutableList.of(
                         ReplacementTestEntry.create(
@@ -532,17 +532,17 @@ final class BugPatternTestExtractorTest {
     verifyGeneratedFileContent(
         outputDirectory,
         "CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest",
-        TestCases.create(
+        BugPatternTestCases.create(
             URI.create(
                 "file:///CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.java"),
             "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest",
             ImmutableList.of(
-                TestCase.create(
+                BugPatternTestCase.create(
                     "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker",
                     ImmutableList.of(
                         IdentificationTestEntry.create(
                             "A.java", "// BUG: Diagnostic contains:\nclass A {}\n"))),
-                TestCase.create(
+                BugPatternTestCase.create(
                     "pkg.CompilationAndBugCheckerRefactoringTestHelpersWithCustomCheckerPackageAndNamesTest.CustomTestChecker2",
                     ImmutableList.of(
                         ReplacementTestEntry.create(
@@ -550,9 +550,9 @@ final class BugPatternTestExtractorTest {
   }
 
   private static void verifyGeneratedFileContent(
-      Path outputDirectory, String testClass, TestCases expected) {
+      Path outputDirectory, String testClass, BugPatternTestCases expected) {
     assertThat(outputDirectory.resolve(String.format("bugpattern-test-%s.json", testClass)))
         .exists()
-        .returns(expected, path -> Json.read(path, TestCases.class));
+        .returns(expected, path -> Json.read(path, BugPatternTestCases.class));
   }
 }

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

@@ -10,7 +10,6 @@ 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;
@@ -41,7 +40,8 @@ final class DocumentationGeneratorTaskListenerTest {
                 entry ->
                     AclEntry.newBuilder(entry)
                         .setPermissions(
-                            Sets.difference(entry.permissions(), ImmutableSet.of(ADD_SUBDIRECTORY)))
+                            Sets.difference(
+                                entry.permissions(), Sets.immutableEnumSet(ADD_SUBDIRECTORY)))
                         .build())
             .collect(toImmutableList()));
 
@@ -93,13 +93,20 @@ 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
@@ -125,8 +132,8 @@ final class DocumentationGeneratorTaskListenerTest {
     }
 
     private static String describeTree(Tree tree) {
-      return (tree instanceof ClassTree)
-          ? String.join(": ", String.valueOf(tree.getKind()), ((ClassTree) tree).getSimpleName())
+      return (tree instanceof ClassTree clazz)
+          ? String.join(": ", String.valueOf(tree.getKind()), clazz.getSimpleName())
           : tree.getKind().toString();
     }
   }

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

@@ -0,0 +1,166 @@
+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));
+  }
+}

error-prone-contrib/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.14.1-SNAPSHOT</version>
+        <version>0.19.2-SNAPSHOT</version>
     </parent>
 
     <artifactId>error-prone-contrib</artifactId>
@@ -55,7 +55,12 @@
         <dependency>
             <groupId>${project.groupId}</groupId>
             <artifactId>refaster-support</artifactId>
-            <scope>provided</scope>
+            <!-- XXX: One would expect this to be a `provided` dependency (as
+            Refaster rules are interpreted by the `refaster-runner` module),
+            but the `OptionalOrElseGet` bug checker defined by this module
+            depends on the `RequiresComputation` matcher that
+            `refaster-support` primarily exposes for use by Refaster rules.
+            Review this setup. (Should the matchers be moved elsewhere?) -->
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
@@ -67,6 +72,11 @@
             <artifactId>jackson-annotations</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>com.github.ben-manes.caffeine</groupId>
+            <artifactId>caffeine</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>com.google.auto.service</groupId>
             <artifactId>auto-service-annotations</artifactId>
@@ -82,6 +92,11 @@
             <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>
@@ -122,6 +137,11 @@
             <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>
@@ -147,6 +167,11 @@
             <artifactId>value-annotations</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.jooq</groupId>
+            <artifactId>jooq</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.jspecify</groupId>
             <artifactId>jspecify</artifactId>
@@ -191,7 +216,7 @@
         </dependency>
         <dependency>
             <groupId>org.openrewrite</groupId>
-            <artifactId>rewrite-java-11</artifactId>
+            <artifactId>rewrite-java-17</artifactId>
             <scope>test</scope>
         </dependency>
         <dependency>
@@ -279,10 +304,58 @@
                             </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>

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

@@ -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;
+import com.sun.source.tree.Tree.Kind;
 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() != Tree.Kind.ENUM) {
+    if (clazz == null || clazz.getKind() != Kind.ENUM) {
       return Description.NO_MATCH;
     }
 

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

@@ -19,7 +19,6 @@ 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;
@@ -119,7 +118,7 @@ public final class CanonicalAnnotationSyntax extends BugChecker implements Annot
        * the expression as a whole.
        */
       ExpressionTree value =
-          (arg.getKind() == Kind.ASSIGNMENT) ? ((AssignmentTree) arg).getExpression() : arg;
+          (arg instanceof AssignmentTree assignment) ? assignment.getExpression() : arg;
 
       /* Store a fix for each expression that was successfully simplified. */
       simplifyAttributeValue(value, state)
@@ -130,13 +129,10 @@ public final class CanonicalAnnotationSyntax extends BugChecker implements Annot
   }
 
   private static Optional<String> simplifyAttributeValue(ExpressionTree expr, VisitorState state) {
-    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));
+    /* Drop curly braces or commas if possible. */
+    return expr instanceof NewArrayTree newArray
+        ? simplifySingletonArray(newArray, state).or(() -> dropTrailingComma(newArray, state))
+        : Optional.empty();
   }
 
   /** Returns the expression describing the array's sole element, if any. */

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

@@ -81,9 +81,8 @@ public final class CanonicalClassNameUsage extends BugChecker
       path = path.getParentPath();
     }
 
-    return path.getLeaf() instanceof MethodInvocationTree
-        && isOwnedByCanonicalNameUsingType(
-            ASTHelpers.getSymbol((MethodInvocationTree) path.getLeaf()));
+    return path.getLeaf() instanceof MethodInvocationTree methodInvocation
+        && isOwnedByCanonicalNameUsingType(ASTHelpers.getSymbol(methodInvocation));
   }
 
   private static boolean isOwnedByCanonicalNameUsingType(MethodSymbol symbol) {

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

@@ -0,0 +1,76 @@
+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"));
+  }
+}

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

@@ -0,0 +1,125 @@
+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));
+  }
+}

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

@@ -101,19 +101,17 @@ public final class DirectReturn extends BugChecker implements BlockTreeMatcher {
   }
 
   private static Optional<ExpressionTree> tryMatchAssignment(Symbol targetSymbol, Tree tree) {
-    if (tree instanceof ExpressionStatementTree) {
-      return tryMatchAssignment(targetSymbol, ((ExpressionStatementTree) tree).getExpression());
+    if (tree instanceof ExpressionStatementTree expressionStatement) {
+      return tryMatchAssignment(targetSymbol, expressionStatement.getExpression());
     }
 
-    if (tree instanceof AssignmentTree) {
-      AssignmentTree assignment = (AssignmentTree) tree;
+    if (tree instanceof AssignmentTree assignment) {
       return targetSymbol.equals(ASTHelpers.getSymbol(assignment.getVariable()))
           ? Optional.of(assignment.getExpression())
           : Optional.empty();
     }
 
-    if (tree instanceof VariableTree) {
-      VariableTree declaration = (VariableTree) tree;
+    if (tree instanceof VariableTree declaration) {
       return declaration.getModifiers().getAnnotations().isEmpty()
               && targetSymbol.equals(ASTHelpers.getSymbol(declaration))
           ? Optional.ofNullable(declaration.getInitializer())
@@ -151,11 +149,11 @@ public final class DirectReturn extends BugChecker implements BlockTreeMatcher {
             Streams.stream(state.getPath()).skip(1),
             Streams.stream(state.getPath()),
             (tree, child) -> {
-              if (!(tree instanceof TryTree)) {
+              if (!(tree instanceof TryTree tryTree)) {
                 return null;
               }
 
-              BlockTree finallyBlock = ((TryTree) tree).getFinallyBlock();
+              BlockTree finallyBlock = tryTree.getFinallyBlock();
               return !child.equals(finallyBlock) ? finallyBlock : null;
             })
         .anyMatch(finallyBlock -> referencesIdentifierSymbol(symbol, finallyBlock));

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

@@ -62,7 +62,7 @@ public final class EmptyMethod extends BugChecker implements MethodTreeMatcher {
   }
 
   private static boolean isInPossibleTestHelperClass(VisitorState state) {
-    return Optional.ofNullable(ASTHelpers.findEnclosingNode(state.getPath(), ClassTree.class))
+    return Optional.ofNullable(state.findEnclosing(ClassTree.class))
         .map(ClassTree::getSimpleName)
         .filter(name -> name.toString().contains("Test"))
         .isPresent();

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

@@ -0,0 +1,89 @@
+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));
+  }
+}

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

@@ -0,0 +1,233 @@
+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")
+          .build();
+
+  /** 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;
+  }
+}

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

@@ -50,8 +50,9 @@ 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,

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

@@ -36,6 +36,7 @@ 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;
 
 /**
@@ -203,14 +204,10 @@ public final class FormatStringConcatenation extends BugChecker
 
     ExpressionTree argument = ASTHelpers.stripParentheses(arguments.get(argPosition));
     return argument instanceof BinaryTree
-        && isStringTyped(argument, state)
+        && MoreASTHelpers.isStringTyped(argument, state)
         && ASTHelpers.constValue(argument, String.class) == null;
   }
 
-  private static boolean isStringTyped(ExpressionTree tree, VisitorState state) {
-    return ASTHelpers.isSameType(ASTHelpers.getType(tree), state.getSymtab().stringType, state);
-  }
-
   private static class ReplacementArgumentsConstructor
       extends SimpleTreeVisitor<@Nullable Void, VisitorState> {
     private final StringBuilder formatString = new StringBuilder();
@@ -223,7 +220,7 @@ public final class FormatStringConcatenation extends BugChecker
 
     @Override
     public @Nullable Void visitBinary(BinaryTree tree, VisitorState state) {
-      if (tree.getKind() == Kind.PLUS && isStringTyped(tree, state)) {
+      if (tree.getKind() == Kind.PLUS && MoreASTHelpers.isStringTyped(tree, state)) {
         tree.getLeftOperand().accept(this, state);
         tree.getRightOperand().accept(this, state);
       } else {
@@ -245,8 +242,8 @@ public final class FormatStringConcatenation extends BugChecker
     }
 
     private void appendExpression(Tree tree) {
-      if (tree instanceof LiteralTree) {
-        formatString.append(((LiteralTree) tree).getValue());
+      if (tree instanceof LiteralTree literal) {
+        formatString.append(literal.getValue());
       } else {
         formatString.append(formatSpecifier);
         formatArguments.add(tree);

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

@@ -39,6 +39,7 @@ 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;
@@ -51,6 +52,7 @@ 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",
@@ -83,6 +85,7 @@ 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()
@@ -124,8 +127,9 @@ 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();

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

@@ -43,8 +43,9 @@ 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,

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

@@ -16,7 +16,6 @@ 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;
 
@@ -26,6 +25,8 @@ import tech.picnic.errorprone.utils.SourceCode;
  */
 // 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.
 @AutoService(BugChecker.class)
 @BugPattern(
     summary = "Prefer `Class::isInstance` method reference over equivalent lambda expression",
@@ -41,12 +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().getKind() != Kind.INSTANCE_OF) {
+    if (tree.getParameters().size() != 1
+        || !(tree.getBody() instanceof InstanceOfTree instanceOf)) {
       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;
     }

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

@@ -16,7 +16,7 @@ import static tech.picnic.errorprone.utils.MoreJUnitMatchers.TEST_METHOD;
 import static tech.picnic.errorprone.utils.MoreMatchers.hasMetaAnnotation;
 
 import com.google.auto.service.AutoService;
-import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
 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,
-            ImmutableSet.of(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC))
+            Sets.immutableEnumSet(Modifier.PRIVATE, Modifier.PROTECTED, Modifier.PUBLIC))
         .ifPresent(fixBuilder::merge);
 
     if (!HAS_SPRING_CONFIGURATION_ANNOTATION.matches(tree, state)) {

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

@@ -101,6 +101,8 @@ 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))

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

@@ -232,7 +232,7 @@ 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, unused);
+        return super.visitReturn(node, null);
       }
 
       @Override
@@ -265,8 +265,8 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
             arguments.stream()
                 .map(
                     arg ->
-                        arg instanceof MethodInvocationTree
-                            ? Iterables.getOnlyElement(((MethodInvocationTree) arg).getArguments())
+                        arg instanceof MethodInvocationTree methodInvocation
+                            ? Iterables.getOnlyElement(methodInvocation.getArguments())
                             : arg)
                 .map(argument -> SourceCode.treeToString(argument, state))
                 .collect(joining(", ")))
@@ -276,16 +276,12 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
   private static String toValueSourceAttributeName(Type type) {
     String typeString = type.tsym.name.toString();
 
-    switch (typeString) {
-      case "Class":
-        return "classes";
-      case "Character":
-        return "chars";
-      case "Integer":
-        return "ints";
-      default:
-        return typeString.toLowerCase(Locale.ROOT) + 's';
-    }
+    return switch (typeString) {
+      case "Class" -> "classes";
+      case "Character" -> "chars";
+      case "Integer" -> "ints";
+      default -> typeString.toLowerCase(Locale.ROOT) + 's';
+    };
   }
 
   private static <T> Optional<T> getElementIfSingleton(Collection<T> collection) {
@@ -297,11 +293,10 @@ public final class JUnitValueSource extends BugChecker implements MethodTreeMatc
   private static Matcher<ExpressionTree> isSingleDimensionArrayCreationWithAllElementsMatching(
       Matcher<? super ExpressionTree> elementMatcher) {
     return (tree, state) -> {
-      if (!(tree instanceof NewArrayTree)) {
+      if (!(tree instanceof NewArrayTree newArray)) {
         return false;
       }
 
-      NewArrayTree newArray = (NewArrayTree) tree;
       return newArray.getDimensions().isEmpty()
           && !newArray.getInitializers().isEmpty()
           && newArray.getInitializers().stream()

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

@@ -14,6 +14,7 @@ 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;
@@ -31,14 +32,11 @@ 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;
@@ -52,6 +50,9 @@ 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",
@@ -65,14 +66,15 @@ 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");
+          "org.springframework.test.context.TestPropertySource#value",
+          "picocli.CommandLine.Option#names");
   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";
@@ -122,13 +124,9 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
   }
 
   private static Optional<NewArrayTree> extractArray(ExpressionTree expr) {
-    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);
+    return expr instanceof AssignmentTree assignment
+        ? extractArray(assignment.getExpression())
+        : Optional.of(expr).filter(NewArrayTree.class::isInstance).map(NewArrayTree.class::cast);
   }
 
   private static Optional<SuggestedFix.Builder> suggestSorting(
@@ -164,7 +162,12 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
 
     /* For now we don't force sorting on numeric types. */
     return Stream.of(
-            symtab.annotationType, symtab.classType, symtab.enumSym.type, symtab.stringType)
+            symtab.annotationType,
+            symtab.booleanType,
+            symtab.charType,
+            symtab.classType,
+            symtab.enumSym.type,
+            symtab.stringType)
         .anyMatch(t -> ASTHelpers.isSubtype(elemType, t, state));
   }
 
@@ -193,24 +196,24 @@ 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, unused);
+        return super.visitIdentifier(node, null);
       }
 
       @Override
       public @Nullable Void visitLiteral(LiteralTree node, @Nullable Void unused) {
         Object value = ASTHelpers.constValue(node);
         nodes.add(
-            value instanceof String
-                ? STRING_ARGUMENT_SPLITTER.splitToStream((String) value).collect(toImmutableList())
+            value instanceof String str
+                ? STRING_ARGUMENT_SPLITTER.splitToStream(str).collect(toImmutableList())
                 : ImmutableList.of(String.valueOf(value)));
 
-        return super.visitLiteral(node, unused);
+        return super.visitLiteral(node, null);
       }
 
       @Override
       public @Nullable Void visitPrimitiveType(PrimitiveTypeTree node, @Nullable Void unused) {
         nodes.add(ImmutableList.of(node.getPrimitiveTypeKind().toString()));
-        return super.visitPrimitiveType(node, unused);
+        return super.visitPrimitiveType(node, null);
       }
     }.scan(array, null);
 
@@ -226,10 +229,8 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
         excludedAnnotations(flags));
   }
 
-  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);
+  private static ImmutableSet<String> excludedAnnotations(ErrorProneFlags flags) {
+    return Sets.union(BLACKLISTED_ANNOTATIONS, Flags.getSet(flags, EXCLUDED_ANNOTATIONS_FLAG))
+        .immutableCopy();
   }
 }

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

@@ -36,6 +36,10 @@ 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",

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

@@ -67,20 +67,19 @@ 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();
-    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;
-    }
+    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;
+    };
   }
 }

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

@@ -24,7 +24,9 @@ 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,

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

@@ -34,8 +34,9 @@ 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,

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

@@ -169,10 +169,9 @@ 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) {
-        MemberSelectTree memberSelectTree = (MemberSelectTree) qualifiedIdentifier;
-        String type = SourceCode.treeToString(memberSelectTree.getExpression(), state);
-        String member = memberSelectTree.getIdentifier().toString();
+      if (importTree.isStatic() && qualifiedIdentifier instanceof MemberSelectTree memberSelect) {
+        String type = SourceCode.treeToString(memberSelect.getExpression(), state);
+        String member = memberSelect.getIdentifier().toString();
         if (shouldNotBeStaticallyImported(type, member)) {
           imports.put(
               type,
@@ -211,7 +210,7 @@ public final class NonStaticImport extends BugChecker implements CompilationUnit
           }
         }
 
-        return super.visitIdentifier(node, unused);
+        return super.visitIdentifier(node, null);
       }
     }.scan(tree, null);
   }

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

@@ -0,0 +1,123 @@
+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());
+  }
+}

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

@@ -22,6 +22,7 @@ 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;
@@ -44,8 +45,9 @@ 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,
@@ -147,38 +149,44 @@ 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) {
-    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();
+    if (tree instanceof LambdaExpressionTree lambdaExpression) {
+      /* Return the lambda expression's actual return type. */
+      return Optional.ofNullable(ASTHelpers.getType(lambdaExpression.getBody()));
     }
+
+    // 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();
-    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 IdentifierTree) {
+      SuggestedFix.Builder fix = SuggestedFix.builder();
+      String replacement =
+          SuggestedFixes.qualifyStaticImport(
+              Comparator.class.getCanonicalName() + '.' + preferredMethodName, fix, state);
+      return fix.replace(expr, replacement).build();
     }
+
+    if (expr instanceof MemberSelectTree memberSelect) {
+      return SuggestedFix.replace(
+          memberSelect,
+          SourceCode.treeToString(memberSelect.getExpression(), state) + '.' + preferredMethodName);
+    }
+
+    throw new VerifyException("Unexpected type of expression: " + expr.getKind());
   }
 }

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

@@ -331,36 +331,32 @@ public final class RedundantStringConversion extends BugChecker
   }
 
   private Optional<ExpressionTree> trySimplify(ExpressionTree tree, VisitorState state) {
-    if (tree.getKind() != Kind.METHOD_INVOCATION) {
+    if (!(tree instanceof MethodInvocationTree methodInvocation)) {
       return Optional.empty();
     }
 
-    MethodInvocationTree methodInvocation = (MethodInvocationTree) tree;
     if (!conversionMethodMatcher.matches(methodInvocation, state)) {
       return Optional.empty();
     }
 
-    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));
-    }
+    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));
+    };
   }
 
   private static Optional<ExpressionTree> trySimplifyNullaryMethod(
       MethodInvocationTree methodInvocation, VisitorState state) {
-    if (!instanceMethod().matches(methodInvocation, state)) {
+    if (!instanceMethod().matches(methodInvocation, state)
+        || !(methodInvocation.getMethodSelect() instanceof MemberSelectTree memberSelect)) {
       return Optional.empty();
     }
 
-    return Optional.of(methodInvocation.getMethodSelect())
-        .filter(methodSelect -> methodSelect.getKind() == Kind.MEMBER_SELECT)
-        .map(methodSelect -> ((MemberSelectTree) methodSelect).getExpression())
+    return Optional.of(memberSelect.getExpression())
         .filter(expr -> !"super".equals(SourceCode.treeToString(expr, state)));
   }
 
@@ -382,11 +378,11 @@ public final class RedundantStringConversion extends BugChecker
 
   private static Matcher<MethodInvocationTree> createConversionMethodMatcher(
       ErrorProneFlags flags) {
-    // 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.
+    // 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.
     return anyOf(
         WELL_KNOWN_STRING_CONVERSION_METHODS,
         new MethodMatcherFactory()
-            .create(Flags.getList(flags, EXTRA_STRING_CONVERSION_METHODS_FLAG)));
+            .create(Flags.getSet(flags, EXTRA_STRING_CONVERSION_METHODS_FLAG)));
   }
 }

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

@@ -0,0 +1,95 @@
+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();
+  }
+}

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

@@ -105,9 +105,10 @@ public final class RequestMappingAnnotation extends BugChecker implements Method
             && LACKS_PARAMETER_ANNOTATION.matches(tree, state)
         ? buildDescription(tree)
             .setMessage(
-                "Not all parameters of this request mapping method are annotated; this may be a "
-                    + "mistake. If the unannotated parameters represent query string parameters, "
-                    + "annotate them with `@RequestParam`.")
+                """
+                Not all parameters of this request mapping method are annotated; this may be a \
+                mistake. If the unannotated parameters represent query string parameters, annotate \
+                them with `@RequestParam`.""")
             .build()
         : Description.NO_MATCH;
   }

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

@@ -15,8 +15,8 @@ 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.ImmutableMap;
+import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
@@ -34,7 +34,9 @@ import tech.picnic.errorprone.utils.Flags;
 @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,
@@ -72,10 +74,10 @@ 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.getList(flags, SUPPORTED_CUSTOM_TYPES_FLAG))));
+        not(isSubtypeOfAny(Flags.getSet(flags, SUPPORTED_CUSTOM_TYPES_FLAG))));
   }
 
-  private static Matcher<Tree> isSubtypeOfAny(ImmutableList<String> inclusions) {
+  private static Matcher<Tree> isSubtypeOfAny(ImmutableSet<String> inclusions) {
     return anyOf(
         inclusions.stream()
             .map(inclusion -> isSubtypeOf(Suppliers.typeFromString(inclusion)))

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/Slf4jLogStatement.java

@@ -41,7 +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> MARKER = isSubtypeOf("org.slf4j.Marker");
+  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> SLF4J_LOGGER_INVOCATION =
       instanceMethod()
@@ -71,7 +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 = MARKER.matches(args.get(0), state) ? 1 : 0;
+    int lTrim = SLF4J_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

error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/Slf4jLoggerDeclaration.java

@@ -0,0 +1,185 @@
+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;
+  }
+}

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

@@ -1,6 +1,5 @@
 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;
@@ -25,7 +24,6 @@ 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;
@@ -80,31 +78,25 @@ public final class SpringMvcAnnotation extends BugChecker implements AnnotationT
   }
 
   private static Optional<String> extractUniqueMethod(ExpressionTree arg, VisitorState state) {
-    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));
+    if (!(arg instanceof AssignmentTree assignment)) {
+      throw new VerifyException("Annotation attribute is not an assignment:" + arg.getKind());
     }
 
-    NewArrayTree newArray = (NewArrayTree) expr;
-    return Optional.of(newArray.getInitializers())
-        .filter(args -> args.size() == 1)
-        .map(args -> extractMethod(args.get(0), 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));
   }
 
+  // XXX: Use switch pattern matching once the targeted JDK supports this.
   private static String extractMethod(ExpressionTree expr, VisitorState state) {
-    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());
-    }
+    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());
+    };
   }
 
   private static Fix replaceAnnotation(

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

@@ -39,11 +39,13 @@ 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;
@@ -100,6 +102,7 @@ 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",
@@ -209,15 +212,10 @@ public final class StaticImport extends BugChecker implements MemberSelectTreeMa
     Tree parentTree =
         requireNonNull(state.getPath().getParentPath(), "MemberSelectTree lacks enclosing node")
             .getLeaf();
-    switch (parentTree.getKind()) {
-      case IMPORT:
-      case MEMBER_SELECT:
-        return false;
-      case METHOD_INVOCATION:
-        return ((MethodInvocationTree) parentTree).getTypeArguments().isEmpty();
-      default:
-        return true;
-    }
+
+    return parentTree instanceof MethodInvocationTree methodInvocation
+        ? methodInvocation.getTypeArguments().isEmpty()
+        : (parentTree.getKind() != Kind.IMPORT && parentTree.getKind() != Kind.MEMBER_SELECT);
   }
 
   private static boolean isCandidate(MemberSelectTree tree) {

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

@@ -23,7 +23,6 @@ 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;
@@ -37,7 +36,9 @@ 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.)
+// (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)`.)
 @AutoService(BugChecker.class)
 @BugPattern(
     summary = "Prefer `String#join` over `String#format`",
@@ -150,7 +151,7 @@ public final class StringJoin extends BugChecker implements MethodInvocationTree
     SuggestedFix.Builder fix =
         SuggestedFix.builder()
             .replace(tree.getMethodSelect(), "String.join")
-            .replace(arguments.next(), Constants.format(separator));
+            .replace(arguments.next(), SourceCode.toStringConstantExpression(separator, state));
 
     while (arguments.hasNext()) {
       ExpressionTree argument = arguments.next();

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

@@ -34,7 +34,9 @@ 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,

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

@@ -3,9 +3,6 @@ package tech.picnic.errorprone.refasterrules;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static org.assertj.core.api.Assertions.assertThat;
 
-import com.google.common.collect.ImmutableList;
-import com.google.common.collect.ImmutableMultiset;
-import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Multiset;
 import com.google.errorprone.refaster.Refaster;
@@ -15,7 +12,6 @@ import com.google.errorprone.refaster.annotation.Matches;
 import com.google.errorprone.refaster.annotation.NotMatches;
 import com.google.errorprone.refaster.annotation.Repeated;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
-import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import java.util.Map;
@@ -204,32 +200,8 @@ final class AssertJRules {
     @SuppressWarnings("unchecked")
     ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T element) {
       return Refaster.anyOf(
-          iterAssert.containsAnyElementsOf(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))),
           iterAssert.containsAnyOf(element),
-          iterAssert.containsAll(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))),
-          iterAssert.containsSequence(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))),
           iterAssert.containsSequence(element),
-          iterAssert.containsSubsequence(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))),
           iterAssert.containsSubsequence(element));
     }
 
@@ -244,20 +216,7 @@ final class AssertJRules {
     @BeforeTemplate
     @SuppressWarnings("unchecked")
     ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T element) {
-      return Refaster.anyOf(
-          iterAssert.doesNotContainAnyElementsOf(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))),
-          iterAssert.doesNotContainSequence(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))),
-          iterAssert.doesNotContainSequence(element));
+      return iterAssert.doesNotContainSequence(element);
     }
 
     @AfterTemplate
@@ -270,25 +229,7 @@ final class AssertJRules {
   static final class ObjectEnumerableContainsExactlyOneElement<S, T extends S> {
     @BeforeTemplate
     @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T element) {
-      return Refaster.anyOf(
-          iterAssert.containsExactlyElementsOf(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))),
-          iterAssert.containsExactlyInAnyOrderElementsOf(
-              Refaster.anyOf(
-                  ImmutableList.of(element),
-                  Arrays.asList(element),
-                  ImmutableSet.of(element),
-                  ImmutableMultiset.of(element))));
-    }
-
-    @BeforeTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> before2(
+    ObjectEnumerableAssert<?, S> before(
         ObjectEnumerableAssert<?, S> iterAssert, @NotMatches(IsArray.class) T element) {
       return iterAssert.containsExactlyInAnyOrder(element);
     }
@@ -313,42 +254,6 @@ final class AssertJRules {
     }
   }
 
-  static final class ObjectEnumerableContainsOneDistinctElement<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T element) {
-      return iterAssert.hasSameElementsAs(
-          Refaster.anyOf(
-              ImmutableList.of(element),
-              Arrays.asList(element),
-              ImmutableSet.of(element),
-              ImmutableMultiset.of(element)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T element) {
-      return iterAssert.containsOnly(element);
-    }
-  }
-
-  static final class ObjectEnumerableIsSubsetOfOneElement<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T element) {
-      return iterAssert.isSubsetOf(
-          Refaster.anyOf(
-              ImmutableList.of(element),
-              Arrays.asList(element),
-              ImmutableSet.of(element),
-              ImmutableMultiset.of(element)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T element) {
-      return iterAssert.isSubsetOf(element);
-    }
-  }
-
   //
   // Iterable
   //
@@ -359,6 +264,7 @@ final class AssertJRules {
       Refaster.anyOf(
           assertThat(iterable).hasSize(0),
           assertThat(iterable.iterator().hasNext()).isFalse(),
+          assertThat(iterable.iterator()).isExhausted(),
           assertThat(Iterables.size(iterable)).isEqualTo(0L),
           assertThat(Iterables.size(iterable)).isNotPositive());
     }
@@ -1155,824 +1061,6 @@ final class AssertJRules {
     }
   }
 
-  ////////////////////////////////////////////////////////////////////////////
-  ////////////////////////////////////////////////////////////////////////////
-  // BELOW: Generated code.
-
-  //
-  // ObjectEnumerableAssert: containsAnyOf
-  //
-
-  static final class ObjectEnumerableContainsAnyOfTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsAnyOf(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableContainsAnyOfThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsAnyOf(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableContainsAnyOfFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsAnyOf(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableContainsAnyOfFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsAnyOf(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: contains
-  //
-
-  static final class ObjectEnumerableContainsTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsAll(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.contains(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableContainsThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsAll(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.contains(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableContainsFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsAll(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.contains(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableContainsFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsAll(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.contains(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: containsExactly
-  //
-
-  static final class ObjectEnumerableContainsExactlyTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsExactlyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsExactly(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableContainsExactlyThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsExactlyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsExactly(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableContainsExactlyFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsExactlyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsExactly(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableContainsExactlyFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsExactlyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsExactly(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: containsExactlyInAnyOrder
-  //
-
-  static final class ObjectEnumerableContainsExactlyInAnyOrderTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsExactlyInAnyOrderElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsExactlyInAnyOrder(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableContainsExactlyInAnyOrderThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsExactlyInAnyOrderElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsExactlyInAnyOrder(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableContainsExactlyInAnyOrderFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsExactlyInAnyOrderElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsExactlyInAnyOrder(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableContainsExactlyInAnyOrderFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsExactlyInAnyOrderElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsExactlyInAnyOrder(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: containsSequence
-  //
-
-  static final class ObjectEnumerableContainsSequenceTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsSequence(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableContainsSequenceThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsSequence(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableContainsSequenceFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsSequence(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableContainsSequenceFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsSequence(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: containsSubsequence
-  //
-
-  static final class ObjectEnumerableContainsSubsequenceTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsSubsequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsSubsequence(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableContainsSubsequenceThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsSubsequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsSubsequence(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableContainsSubsequenceFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsSubsequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsSubsequence(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableContainsSubsequenceFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsSubsequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsSubsequence(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: doesNotContain
-  //
-
-  static final class ObjectEnumerableDoesNotContainTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.doesNotContainAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.doesNotContain(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableDoesNotContainThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.doesNotContainAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.doesNotContain(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableDoesNotContainFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.doesNotContainAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.doesNotContain(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableDoesNotContainFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.doesNotContainAnyElementsOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.doesNotContain(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: doesNotContainSequence
-  //
-
-  static final class ObjectEnumerableDoesNotContainSequenceTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.doesNotContainSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.doesNotContainSequence(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableDoesNotContainSequenceThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.doesNotContainSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.doesNotContainSequence(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableDoesNotContainSequenceFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.doesNotContainSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.doesNotContainSequence(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableDoesNotContainSequenceFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.doesNotContainSequence(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.doesNotContainSequence(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: containsOnly
-  //
-
-  static final class ObjectEnumerableContainsOnlyTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.hasSameElementsAs(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.containsOnly(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableContainsOnlyThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.hasSameElementsAs(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.containsOnly(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableContainsOnlyFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.hasSameElementsAs(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.containsOnly(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableContainsOnlyFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.hasSameElementsAs(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.containsOnly(e1, e2, e3, e4, e5);
-    }
-  }
-
-  //
-  // ObjectEnumerableAssert: isSubsetOf
-  //
-
-  static final class ObjectEnumerableIsSubsetOfTwoElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.isSubsetOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2),
-              Arrays.asList(e1, e2),
-              ImmutableSet.of(e1, e2),
-              ImmutableMultiset.of(e1, e2)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2) {
-      return iterAssert.isSubsetOf(e1, e2);
-    }
-  }
-
-  static final class ObjectEnumerableIsSubsetOfThreeElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.isSubsetOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3),
-              Arrays.asList(e1, e2, e3),
-              ImmutableSet.of(e1, e2, e3),
-              ImmutableMultiset.of(e1, e2, e3)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3) {
-      return iterAssert.isSubsetOf(e1, e2, e3);
-    }
-  }
-
-  static final class ObjectEnumerableIsSubsetOfFourElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.isSubsetOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4),
-              Arrays.asList(e1, e2, e3, e4),
-              ImmutableSet.of(e1, e2, e3, e4),
-              ImmutableMultiset.of(e1, e2, e3, e4)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4) {
-      return iterAssert.isSubsetOf(e1, e2, e3, e4);
-    }
-  }
-
-  // XXX: Add variants for 6+ elements?
-  static final class ObjectEnumerableIsSubsetOfFiveElements<S, T extends S> {
-    @BeforeTemplate
-    ObjectEnumerableAssert<?, S> before(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.isSubsetOf(
-          Refaster.anyOf(
-              ImmutableList.of(e1, e2, e3, e4, e5),
-              Arrays.asList(e1, e2, e3, e4, e5),
-              ImmutableSet.of(e1, e2, e3, e4, e5),
-              ImmutableMultiset.of(e1, e2, e3, e4, e5)));
-    }
-
-    @AfterTemplate
-    @SuppressWarnings("unchecked")
-    ObjectEnumerableAssert<?, S> after(
-        ObjectEnumerableAssert<?, S> iterAssert, T e1, T e2, T e3, T e4, T e5) {
-      return iterAssert.isSubsetOf(e1, e2, e3, e4, e5);
-    }
-  }
-
-  ////////////////////////////////////////////////////////////////////////////
-  ////////////////////////////////////////////////////////////////////////////
-  // Above: Generated code.
-
   ////////////////////////////////////////////////////////////////////////////
   ////////////////////////////////////////////////////////////////////////////
   // Organize the code below.

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

@@ -12,6 +12,7 @@ import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.nio.file.Path;
 import org.assertj.core.api.AbstractAssert;
+import org.assertj.core.api.AbstractBooleanAssert;
 import org.assertj.core.api.AbstractStringAssert;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
@@ -69,6 +70,32 @@ final class AssertJStringRules {
     }
   }
 
+  static final class AssertThatStringContains {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(String string, String substring) {
+      return assertThat(string.contains(substring)).isTrue();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractStringAssert<?> after(String string, String substring) {
+      return assertThat(string).contains(substring);
+    }
+  }
+
+  static final class AssertThatStringDoesNotContain {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(String string, String substring) {
+      return assertThat(string.contains(substring)).isFalse();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractStringAssert<?> after(String string, String substring) {
+      return assertThat(string).doesNotContain(substring);
+    }
+  }
+
   static final class AssertThatMatches {
     @BeforeTemplate
     AbstractAssert<?, ?> before(String string, String regex) {

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

@@ -7,7 +7,10 @@ import static org.assertj.core.api.Assertions.assertThatIllegalArgumentException
 import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 import static org.assertj.core.api.Assertions.assertThatNullPointerException;
 import static org.assertj.core.api.Assertions.assertThatThrownBy;
+import static org.assertj.core.api.InstanceOfAssertFactories.throwable;
+import static org.assertj.core.api.InstanceOfAssertFactories.type;
 
+import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.Repeated;
@@ -16,6 +19,7 @@ import java.io.IOException;
 import org.assertj.core.api.AbstractObjectAssert;
 import org.assertj.core.api.AbstractThrowableAssert;
 import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
+import org.assertj.core.api.ThrowableAssertAlternative;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
 /**
@@ -31,6 +35,21 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 final class AssertJThrowingCallableRules {
   private AssertJThrowingCallableRules() {}
 
+  static final class AssertThatThrownByIsInstanceOf<T extends Throwable> {
+    @BeforeTemplate
+    void before(ThrowingCallable throwingCallable, Class<T> exceptionType) {
+      Refaster.anyOf(
+          assertThatThrownBy(throwingCallable).asInstanceOf(throwable(exceptionType)),
+          assertThatThrownBy(throwingCallable).asInstanceOf(type(exceptionType)));
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    void after(ThrowingCallable throwingCallable, Class<T> exceptionType) {
+      assertThatThrownBy(throwingCallable).isInstanceOf(exceptionType);
+    }
+  }
+
   static final class AssertThatThrownByIllegalArgumentException {
     @BeforeTemplate
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable) {
@@ -61,6 +80,27 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByIllegalArgumentExceptionRootCauseHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalArgumentException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalArgumentException()
+          .isThrownBy(throwingCallable)
+          .havingRootCause()
+          .withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalArgumentException.class)
+          .rootCause()
+          .hasMessage(message);
+    }
+  }
+
   static final class AssertThatThrownByIllegalArgumentExceptionHasMessageParameters {
     @BeforeTemplate
     @SuppressWarnings(
@@ -171,6 +211,27 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByIllegalStateExceptionRootCauseHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalStateException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIllegalStateException()
+          .isThrownBy(throwingCallable)
+          .havingRootCause()
+          .withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalStateException.class)
+          .rootCause()
+          .hasMessage(message);
+    }
+  }
+
   static final class AssertThatThrownByIllegalStateExceptionHasMessageParameters {
     @BeforeTemplate
     @SuppressWarnings(
@@ -279,6 +340,27 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByNullPointerExceptionRootCauseHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByNullPointerException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatNullPointerException()
+          .isThrownBy(throwingCallable)
+          .havingRootCause()
+          .withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(NullPointerException.class)
+          .rootCause()
+          .hasMessage(message);
+    }
+  }
+
   static final class AssertThatThrownByNullPointerExceptionHasMessageParameters {
     @BeforeTemplate
     @SuppressWarnings(
@@ -386,6 +468,26 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByIOExceptionRootCauseHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownByIOException" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
+      return assertThatIOException()
+          .isThrownBy(throwingCallable)
+          .havingRootCause()
+          .withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(ThrowingCallable throwingCallable, String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IOException.class)
+          .rootCause()
+          .hasMessage(message);
+    }
+  }
+
   static final class AssertThatThrownByIOExceptionHasMessageParameters {
     @BeforeTemplate
     @SuppressWarnings("AssertThatThrownByIOException" /* This is a more specific template. */)
@@ -452,24 +554,24 @@ final class AssertJThrowingCallableRules {
     }
   }
 
-  static final class AssertThatThrownBy {
+  static final class AssertThatThrownByAsInstanceOfThrowable<T extends Throwable> {
     @BeforeTemplate
-    AbstractObjectAssert<?, ?> before(
-        ThrowingCallable throwingCallable, Class<? extends Throwable> exceptionType) {
+    ThrowableAssertAlternative<T> before(
+        ThrowingCallable throwingCallable, Class<T> exceptionType) {
       return assertThatExceptionOfType(exceptionType).isThrownBy(throwingCallable);
     }
 
     @AfterTemplate
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    AbstractObjectAssert<?, ?> after(
-        ThrowingCallable throwingCallable, Class<? extends Throwable> exceptionType) {
-      return assertThatThrownBy(throwingCallable).isInstanceOf(exceptionType);
+    AbstractThrowableAssert<?, T> after(ThrowingCallable throwingCallable, Class<T> exceptionType) {
+      return assertThatThrownBy(throwingCallable).asInstanceOf(throwable(exceptionType));
     }
   }
 
   static final class AssertThatThrownByHasMessage {
     @BeforeTemplate
-    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    @SuppressWarnings(
+        "AssertThatThrownByAsInstanceOfThrowable" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable,
         Class<? extends Throwable> exceptionType,
@@ -489,9 +591,37 @@ final class AssertJThrowingCallableRules {
     }
   }
 
+  static final class AssertThatThrownByRootCauseHasMessage {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByAsInstanceOfThrowable" /* This is a more specific template. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatExceptionOfType(exceptionType)
+          .isThrownBy(throwingCallable)
+          .havingRootCause()
+          .withMessage(message);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable,
+        Class<? extends Throwable> exceptionType,
+        String message) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(exceptionType)
+          .rootCause()
+          .hasMessage(message);
+    }
+  }
+
   static final class AssertThatThrownByHasMessageParameters {
     @BeforeTemplate
-    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    @SuppressWarnings(
+        "AssertThatThrownByAsInstanceOfThrowable" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable,
         Class<? extends Throwable> exceptionType,
@@ -517,7 +647,8 @@ final class AssertJThrowingCallableRules {
 
   static final class AssertThatThrownByHasMessageStartingWith {
     @BeforeTemplate
-    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    @SuppressWarnings(
+        "AssertThatThrownByAsInstanceOfThrowable" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable,
         Class<? extends Throwable> exceptionType,
@@ -541,7 +672,8 @@ final class AssertJThrowingCallableRules {
 
   static final class AssertThatThrownByHasMessageContaining {
     @BeforeTemplate
-    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    @SuppressWarnings(
+        "AssertThatThrownByAsInstanceOfThrowable" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable,
         Class<? extends Throwable> exceptionType,
@@ -565,7 +697,8 @@ final class AssertJThrowingCallableRules {
 
   static final class AssertThatThrownByHasMessageNotContaining {
     @BeforeTemplate
-    @SuppressWarnings("AssertThatThrownBy" /* This is a more specific template. */)
+    @SuppressWarnings(
+        "AssertThatThrownByAsInstanceOfThrowable" /* This is a more specific template. */)
     AbstractObjectAssert<?, ?> before(
         ThrowingCallable throwingCallable,
         Class<? extends Throwable> exceptionType,

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

@@ -1,8 +1,6 @@
 package tech.picnic.errorprone.refasterrules;
 
 import static com.google.common.base.Preconditions.checkElementIndex;
-import static com.google.common.collect.ImmutableSet.toImmutableSet;
-import static com.google.common.collect.Sets.toImmutableEnumSet;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Collections.disjoint;
 import static java.util.Objects.checkIndex;
@@ -70,28 +68,6 @@ final class AssortedRules {
     }
   }
 
-  /**
-   * Use {@link Sets#toImmutableEnumSet()} when possible, as it is more efficient than {@link
-   * ImmutableSet#toImmutableSet()} and produces a more compact object.
-   *
-   * <p><strong>Warning:</strong> this rewrite rule is not completely behavior preserving: while the
-   * original code produces a set that iterates over the elements in encounter order, the
-   * replacement code iterates over the elements in enum definition order.
-   */
-  // XXX: ^ Consider emitting a comment warning about this fact?
-  static final class StreamToImmutableEnumSet<T extends Enum<T>> {
-    @BeforeTemplate
-    ImmutableSet<T> before(Stream<T> stream) {
-      return stream.collect(toImmutableSet());
-    }
-
-    @AfterTemplate
-    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
-    ImmutableSet<T> after(Stream<T> stream) {
-      return stream.collect(toImmutableEnumSet());
-    }
-  }
-
   /** Prefer {@link Iterators#getNext(Iterator, Object)} over more contrived alternatives. */
   static final class IteratorGetNextOrDefault<T> {
     @BeforeTemplate

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

@@ -9,7 +9,9 @@ import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.sun.tools.javac.util.Constants;
 import com.sun.tools.javac.util.Convert;
+import javax.lang.model.element.Name;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.utils.SourceCode;
 
 /** Refaster rules related to {@link com.google.errorprone.bugpatterns.BugChecker} classes. */
 @OnlineDocumentation
@@ -55,16 +57,44 @@ final class BugCheckerRules {
     }
   }
 
-  /** Prefer using the {@link Constants} API over more verbose alternatives. */
+  /**
+   * Prefer {@link SourceCode#toStringConstantExpression(Object,
+   * com.google.errorprone.VisitorState)} over alternatives that unnecessarily escape single quote
+   * characters.
+   */
   static final class ConstantsFormat {
+    @BeforeTemplate
+    String before(CharSequence value) {
+      return Constants.format(value);
+    }
+
     @BeforeTemplate
     String before(String value) {
       return String.format("\"%s\"", Convert.quote(value));
     }
 
     @AfterTemplate
-    String after(String value) {
-      return Constants.format(value);
+    String after(CharSequence value) {
+      return SourceCode.toStringConstantExpression(
+          value, Refaster.emitCommentBefore("REPLACEME", null));
+    }
+  }
+
+  /** Prefer {@link Name#contentEquals(CharSequence)} over more verbose alternatives. */
+  static final class NameContentEquals {
+    @BeforeTemplate
+    boolean before(Name name, CharSequence string) {
+      return name.toString().equals(string.toString());
+    }
+
+    @BeforeTemplate
+    boolean before(Name name, String string) {
+      return name.toString().equals(string);
+    }
+
+    @AfterTemplate
+    boolean after(Name name, CharSequence string) {
+      return name.contentEquals(string);
     }
   }
 }

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

@@ -0,0 +1,33 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.errorprone.refaster.Refaster;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.AlsoNegation;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to expressions dealing with {@link CharSequence}s. */
+@OnlineDocumentation
+final class CharSequenceRules {
+  private CharSequenceRules() {}
+
+  /**
+   * Prefer {@link CharSequence#isEmpty()} over alternatives that consult the char sequence's
+   * length.
+   */
+  // XXX: Drop this rule once we (and OpenRewrite) no longer support projects targeting Java 14 or
+  // below.
+  static final class CharSequenceIsEmpty {
+    @BeforeTemplate
+    boolean before(CharSequence charSequence) {
+      return Refaster.anyOf(
+          charSequence.length() == 0, charSequence.length() <= 0, charSequence.length() < 1);
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(CharSequence charSequence) {
+      return charSequence.isEmpty();
+    }
+  }
+}

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

@@ -3,6 +3,7 @@ package tech.picnic.errorprone.refasterrules;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import java.util.function.Function;
 import java.util.function.Predicate;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
@@ -37,7 +38,12 @@ final class ClassRules {
     }
   }
 
-  /** Prefer {@link Class#isInstance(Object)} method references over more verbose alternatives. */
+  /**
+   * Prefer {@link Class#isInstance(Object)} method references over lambda expressions that require
+   * naming a variable.
+   */
+  // XXX: Once the `ClassReferenceIsInstancePredicate` rule is dropped, rename this rule to just
+  // `ClassIsInstancePredicate`.
   static final class ClassLiteralIsInstancePredicate<T, S> {
     @BeforeTemplate
     Predicate<S> before() {
@@ -50,7 +56,11 @@ final class ClassRules {
     }
   }
 
-  /** Prefer {@link Class#isInstance(Object)} method references over more verbose alternatives. */
+  /**
+   * Prefer {@link Class#isInstance(Object)} method references over lambda expressions that require
+   * naming a variable.
+   */
+  // XXX: Drop this rule once the `MethodReferenceUsage` rule is enabled by default.
   static final class ClassReferenceIsInstancePredicate<T, S> {
     @BeforeTemplate
     Predicate<S> before(Class<T> clazz) {
@@ -62,4 +72,21 @@ final class ClassRules {
       return clazz::isInstance;
     }
   }
+
+  /**
+   * Prefer {@link Class#cast(Object)} method references over lambda expressions that require naming
+   * a variable.
+   */
+  // XXX: Drop this rule once the `MethodReferenceUsage` rule is enabled by default.
+  static final class ClassReferenceCast<T, S> {
+    @BeforeTemplate
+    Function<T, S> before(Class<? extends S> clazz) {
+      return o -> clazz.cast(o);
+    }
+
+    @AfterTemplate
+    Function<T, S> after(Class<? extends S> clazz) {
+      return clazz::cast;
+    }
+  }
 }

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

@@ -8,7 +8,9 @@ import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.AlsoNegation;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.NotMatches;
 import java.util.ArrayList;
+import java.util.Arrays;
 import java.util.Collection;
 import java.util.Iterator;
 import java.util.List;
@@ -21,6 +23,7 @@ import java.util.function.Consumer;
 import java.util.function.IntFunction;
 import java.util.stream.Stream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.matchers.IsRefasterAsVarargs;
 
 /** Refaster rules related to expressions dealing with (arbitrary) collections. */
 // XXX: There are other Guava `Iterables` methods that should not be called if the input is known to
@@ -35,13 +38,21 @@ final class CollectionRules {
    */
   static final class CollectionIsEmpty<T> {
     @BeforeTemplate
-    @SuppressWarnings("java:S1155" /* This violation will be rewritten. */)
+    @SuppressWarnings({
+      "java:S1155" /* This violation will be rewritten. */,
+      "LexicographicalAnnotationAttributeListing" /* `key-*` entry must remain last. */,
+      "OptionalFirstCollectionElement" /* This is a more specific template. */,
+      "StreamFindAnyIsEmpty" /* This is a more specific template. */,
+      "key-to-resolve-AnnotationUseStyle-and-TrailingComment-check-conflict"
+    })
     boolean before(Collection<T> collection) {
       return Refaster.anyOf(
           collection.size() == 0,
           collection.size() <= 0,
           collection.size() < 1,
-          Iterables.isEmpty(collection));
+          Iterables.isEmpty(collection),
+          collection.stream().findAny().isEmpty(),
+          collection.stream().findFirst().isEmpty());
     }
 
     @BeforeTemplate
@@ -176,6 +187,24 @@ final class CollectionRules {
     }
   }
 
+  /** Don't unnecessarily call {@link Stream#distinct()} on an already-unique stream of elements. */
+  // XXX: This rule assumes that the `Set` relies on `Object#equals`, rather than a custom
+  // equivalence relation.
+  // XXX: Expressions that drop or reorder elements from the stream, such as `.filter`, `.skip` and
+  // `sorted`, can similarly be simplified. Covering all cases is better done using an Error Prone
+  // check.
+  static final class SetStream<T> {
+    @BeforeTemplate
+    Stream<?> before(Set<T> set) {
+      return set.stream().distinct();
+    }
+
+    @AfterTemplate
+    Stream<?> after(Set<T> set) {
+      return set.stream();
+    }
+  }
+
   /** Prefer {@link ArrayList#ArrayList(Collection)} over the Guava alternative. */
   @SuppressWarnings(
       "NonApiType" /* Matching against `List` would unnecessarily constrain the rule. */)
@@ -268,6 +297,23 @@ final class CollectionRules {
     }
   }
 
+  /** Prefer {@link Arrays#asList(Object[])} over more contrived alternatives. */
+  // XXX: Consider moving this rule to `ImmutableListRules` and having it suggest
+  // `ImmutableList#copyOf`. That would retain immutability, at the cost of no longer handling
+  // `null`s.
+  static final class ArraysAsList<T> {
+    // XXX: This expression produces an unmodifiable list, while the alternative doesn't.
+    @BeforeTemplate
+    List<T> before(@NotMatches(IsRefasterAsVarargs.class) T[] array) {
+      return Arrays.stream(array).toList();
+    }
+
+    @AfterTemplate
+    List<T> after(T[] array) {
+      return Arrays.asList(array);
+    }
+  }
+
   /** Prefer calling {@link Collection#toArray()} over more contrived alternatives. */
   static final class CollectionToArray<T> {
     @BeforeTemplate
@@ -319,25 +365,29 @@ final class CollectionRules {
     }
   }
 
-  /**
-   * Don't call {@link ImmutableCollection#asList()} if {@link ImmutableCollection#iterator()} is
-   * called on the result; call it directly.
-   */
-  static final class ImmutableCollectionIterator<T> {
+  /** Prefer {@link Collection#iterator()} over more contrived or less efficient alternatives. */
+  static final class CollectionIterator<T> {
+    @BeforeTemplate
+    Iterator<T> before(Collection<T> collection) {
+      return collection.stream().iterator();
+    }
+
     @BeforeTemplate
     Iterator<T> before(ImmutableCollection<T> collection) {
       return collection.asList().iterator();
     }
 
     @AfterTemplate
-    Iterator<T> after(ImmutableCollection<T> collection) {
+    Iterator<T> after(Collection<T> collection) {
       return collection.iterator();
     }
   }
 
   /**
    * Don't use the ternary operator to extract the first element of a possibly-empty {@link
-   * Collection} as an {@link Optional}.
+   * Collection} as an {@link Optional}, and (when applicable) prefer {@link Stream#findFirst()}
+   * over {@link Stream#findAny()} to communicate that the collection's first element (if any,
+   * according to iteration order) will be returned.
    */
   static final class OptionalFirstCollectionElement<T> {
     @BeforeTemplate

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

@@ -16,13 +16,18 @@ import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.AlsoNegation;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.Matches;
+import com.google.errorprone.refaster.annotation.MayOptionallyUse;
+import com.google.errorprone.refaster.annotation.Placeholder;
 import com.google.errorprone.refaster.annotation.Repeated;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.Collections;
 import java.util.Comparator;
+import java.util.List;
 import java.util.Optional;
 import java.util.function.BinaryOperator;
 import java.util.function.Function;
@@ -92,6 +97,24 @@ final class ComparatorRules {
     }
   }
 
+  /** Don't explicitly compare enums by their ordinal. */
+  abstract static class ComparingEnum<E extends Enum<E>, T> {
+    @Placeholder(allowsIdentity = true)
+    abstract E toEnumFunction(@MayOptionallyUse T value);
+
+    @BeforeTemplate
+    @SuppressWarnings("EnumOrdinal" /* This violation will be rewritten. */)
+    Comparator<T> before() {
+      return comparingInt(v -> toEnumFunction(v).ordinal());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    Comparator<T> after() {
+      return comparing(v -> toEnumFunction(v));
+    }
+  }
+
   /** Don't explicitly create {@link Comparator}s unnecessarily. */
   static final class ThenComparing<S, T extends Comparable<? super T>> {
     @BeforeTemplate
@@ -222,18 +245,77 @@ final class ComparatorRules {
     }
   }
 
+  /** Prefer {@link Collections#sort(List)} over more verbose alternatives. */
+  static final class CollectionsSort<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    void before(List<T> collection) {
+      Collections.sort(collection, naturalOrder());
+    }
+
+    @AfterTemplate
+    void after(List<T> collection) {
+      Collections.sort(collection);
+    }
+  }
+
+  /** Prefer {@link Collections#min(Collection)} over more verbose alternatives. */
+  static final class CollectionsMin<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    T before(Collection<T> collection) {
+      return Refaster.anyOf(
+          Collections.min(collection, naturalOrder()), Collections.max(collection, reverseOrder()));
+    }
+
+    @AfterTemplate
+    T after(Collection<T> collection) {
+      return Collections.min(collection);
+    }
+  }
+
   /**
    * Avoid unnecessary creation of a {@link Stream} to determine the minimum of a known collection
    * of values.
    */
-  static final class MinOfVarargs<T> {
+  static final class MinOfArray<S, T extends S> {
     @BeforeTemplate
-    T before(@Repeated T value, Comparator<T> cmp) {
+    T before(T[] array, Comparator<S> cmp) {
+      return Arrays.stream(array).min(cmp).orElseThrow();
+    }
+
+    @AfterTemplate
+    T after(T[] array, Comparator<S> cmp) {
+      return Collections.min(Arrays.asList(array), cmp);
+    }
+  }
+
+  /**
+   * Avoid unnecessary creation of a {@link Stream} to determine the minimum of a known collection
+   * of values.
+   */
+  static final class CollectionsMinWithComparator<S, T extends S> {
+    @BeforeTemplate
+    T before(Collection<T> collection, Comparator<S> cmp) {
+      return collection.stream().min(cmp).orElseThrow();
+    }
+
+    @AfterTemplate
+    T after(Collection<T> collection, Comparator<S> cmp) {
+      return Collections.min(collection, cmp);
+    }
+  }
+
+  /**
+   * Avoid unnecessary creation of a {@link Stream} to determine the minimum of a known collection
+   * of values.
+   */
+  static final class MinOfVarargs<S, T extends S> {
+    @BeforeTemplate
+    T before(@Repeated T value, Comparator<S> cmp) {
       return Stream.of(Refaster.asVarargs(value)).min(cmp).orElseThrow();
     }
 
     @AfterTemplate
-    T after(@Repeated T value, Comparator<T> cmp) {
+    T after(@Repeated T value, Comparator<S> cmp) {
       return Collections.min(Arrays.asList(value), cmp);
     }
   }
@@ -269,7 +351,7 @@ final class ComparatorRules {
   static final class MinOfPairCustomOrder<T> {
     @BeforeTemplate
     @SuppressWarnings("java:S1067" /* The conditional operators are independent. */)
-    T before(T value1, T value2, Comparator<T> cmp) {
+    T before(T value1, T value2, Comparator<? super T> cmp) {
       return Refaster.anyOf(
           cmp.compare(value1, value2) <= 0 ? value1 : value2,
           cmp.compare(value1, value2) > 0 ? value2 : value1,
@@ -284,23 +366,69 @@ final class ComparatorRules {
     }
 
     @AfterTemplate
-    T after(T value1, T value2, Comparator<T> cmp) {
+    T after(T value1, T value2, Comparator<? super T> cmp) {
       return Comparators.min(value1, value2, cmp);
     }
   }
 
+  /** Prefer {@link Collections#max(Collection)} over more verbose alternatives. */
+  static final class CollectionsMax<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    T before(Collection<T> collection) {
+      return Refaster.anyOf(
+          Collections.max(collection, naturalOrder()), Collections.min(collection, reverseOrder()));
+    }
+
+    @AfterTemplate
+    T after(Collection<T> collection) {
+      return Collections.max(collection);
+    }
+  }
+
   /**
    * Avoid unnecessary creation of a {@link Stream} to determine the maximum of a known collection
    * of values.
    */
-  static final class MaxOfVarargs<T> {
+  static final class MaxOfArray<S, T extends S> {
     @BeforeTemplate
-    T before(@Repeated T value, Comparator<T> cmp) {
+    T before(T[] array, Comparator<S> cmp) {
+      return Arrays.stream(array).max(cmp).orElseThrow();
+    }
+
+    @AfterTemplate
+    T after(T[] array, Comparator<S> cmp) {
+      return Collections.max(Arrays.asList(array), cmp);
+    }
+  }
+
+  /**
+   * Avoid unnecessary creation of a {@link Stream} to determine the maximum of a known collection
+   * of values.
+   */
+  static final class CollectionsMaxWithComparator<S, T extends S> {
+    @BeforeTemplate
+    T before(Collection<T> collection, Comparator<S> cmp) {
+      return collection.stream().max(cmp).orElseThrow();
+    }
+
+    @AfterTemplate
+    T after(Collection<T> collection, Comparator<S> cmp) {
+      return Collections.max(collection, cmp);
+    }
+  }
+
+  /**
+   * Avoid unnecessary creation of a {@link Stream} to determine the maximum of a known collection
+   * of values.
+   */
+  static final class MaxOfVarargs<S, T extends S> {
+    @BeforeTemplate
+    T before(@Repeated T value, Comparator<S> cmp) {
       return Stream.of(Refaster.asVarargs(value)).max(cmp).orElseThrow();
     }
 
     @AfterTemplate
-    T after(@Repeated T value, Comparator<T> cmp) {
+    T after(@Repeated T value, Comparator<S> cmp) {
       return Collections.max(Arrays.asList(value), cmp);
     }
   }
@@ -336,7 +464,7 @@ final class ComparatorRules {
   static final class MaxOfPairCustomOrder<T> {
     @BeforeTemplate
     @SuppressWarnings("java:S1067" /* The conditional operators are independent. */)
-    T before(T value1, T value2, Comparator<T> cmp) {
+    T before(T value1, T value2, Comparator<? super T> cmp) {
       return Refaster.anyOf(
           cmp.compare(value1, value2) >= 0 ? value1 : value2,
           cmp.compare(value1, value2) < 0 ? value2 : value1,
@@ -351,7 +479,7 @@ final class ComparatorRules {
     }
 
     @AfterTemplate
-    T after(T value1, T value2, Comparator<T> cmp) {
+    T after(T value1, T value2, Comparator<? super T> cmp) {
       return Comparators.max(value1, value2, cmp);
     }
   }
@@ -419,4 +547,34 @@ final class ComparatorRules {
       return maxBy(naturalOrder());
     }
   }
+
+  /** Don't explicitly compare enums by their ordinal. */
+  static final class IsLessThan<E extends Enum<E>> {
+    @BeforeTemplate
+    @SuppressWarnings("EnumOrdinal" /* This violation will be rewritten. */)
+    boolean before(E value1, E value2) {
+      return value1.ordinal() < value2.ordinal();
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(E value1, E value2) {
+      return value1.compareTo(value2) < 0;
+    }
+  }
+
+  /** Don't explicitly compare enums by their ordinal. */
+  static final class IsLessThanOrEqualTo<E extends Enum<E>> {
+    @BeforeTemplate
+    @SuppressWarnings("EnumOrdinal" /* This violation will be rewritten. */)
+    boolean before(E value1, E value2) {
+      return value1.ordinal() <= value2.ordinal();
+    }
+
+    @AfterTemplate
+    @AlsoNegation
+    boolean after(E value1, E value2) {
+      return value1.compareTo(value2) <= 0;
+    }
+  }
 }

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

@@ -1,5 +1,6 @@
 package tech.picnic.errorprone.refasterrules;
 
+import static java.util.function.Predicate.isEqual;
 import static java.util.function.Predicate.not;
 
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
@@ -19,9 +20,9 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 final class EqualityRules {
   private EqualityRules() {}
 
-  /** Prefer reference-based quality for enums. */
-  // Primitive value comparisons are not listed, because Error Prone flags those out of the box.
-  static final class PrimitiveOrReferenceEquality<T extends Enum<T>> {
+  /** Prefer reference-based equality for enums. */
+  // Primitive value comparisons are not matched, because Error Prone flags those out of the box.
+  static final class EnumReferenceEquality<T extends Enum<T>> {
     /**
      * Enums can be compared by reference. It is safe to do so even in the face of refactorings,
      * because if the type is ever converted to a non-enum, then Error-Prone will complain about any
@@ -30,8 +31,9 @@ final class EqualityRules {
     // XXX: This Refaster rule is the topic of https://github.com/google/error-prone/issues/559. We
     // work around the issue by selecting the "largest replacements". See the `Refaster` check.
     @BeforeTemplate
+    @SuppressWarnings("EnumOrdinal" /* This violation will be rewritten. */)
     boolean before(T a, T b) {
-      return Refaster.anyOf(a.equals(b), Objects.equals(a, b));
+      return Refaster.anyOf(a.equals(b), Objects.equals(a, b), a.ordinal() == b.ordinal());
     }
 
     @AfterTemplate
@@ -42,6 +44,20 @@ final class EqualityRules {
     }
   }
 
+  /** Prefer reference-based equality for enums. */
+  static final class EnumReferenceEqualityLambda<T extends Enum<T>> {
+    @BeforeTemplate
+    Predicate<T> before(T e) {
+      return Refaster.anyOf(isEqual(e), e::equals);
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("java:S1698" /* Reference comparison is valid for enums. */)
+    Predicate<T> after(T e) {
+      return v -> v == e;
+    }
+  }
+
   /** Prefer {@link Object#equals(Object)} over the equivalent lambda function. */
   // XXX: As it stands, this rule is a special case of what `MethodReferenceUsage` tries to achieve.
   // If/when `MethodReferenceUsage` becomes production ready, we should simply drop this check.

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

@@ -2,12 +2,18 @@ package tech.picnic.errorprone.refasterrules;
 
 import static java.nio.charset.StandardCharsets.UTF_8;
 
+import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.Repeated;
+import java.io.File;
 import java.io.IOException;
+import java.net.URI;
 import java.nio.charset.Charset;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.attribute.FileAttribute;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
 /** Refaster rules related to expressions dealing with files. */
@@ -15,6 +21,49 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 final class FileRules {
   private FileRules() {}
 
+  /** Prefer the more idiomatic {@link Path#of(URI)} over {@link Paths#get(URI)}. */
+  static final class PathOfUri {
+    @BeforeTemplate
+    Path before(URI uri) {
+      return Paths.get(uri);
+    }
+
+    @AfterTemplate
+    Path after(URI uri) {
+      return Path.of(uri);
+    }
+  }
+
+  /**
+   * Prefer the more idiomatic {@link Path#of(String, String...)} over {@link Paths#get(String,
+   * String...)}.
+   */
+  static final class PathOfString {
+    @BeforeTemplate
+    Path before(String first, @Repeated String more) {
+      return Paths.get(first, more);
+    }
+
+    @AfterTemplate
+    Path after(String first, @Repeated String more) {
+      return Path.of(first, more);
+    }
+  }
+
+  /** Avoid redundant conversions from {@link Path} to {@link File}. */
+  // XXX: Review whether a rule such as this one is better handled by the `IdentityConversion` rule.
+  static final class PathInstance {
+    @BeforeTemplate
+    Path before(Path path) {
+      return path.toFile().toPath();
+    }
+
+    @AfterTemplate
+    Path after(Path path) {
+      return path;
+    }
+  }
+
   /** Prefer {@link Files#readString(Path, Charset)} over more contrived alternatives. */
   static final class FilesReadStringWithCharset {
     @BeforeTemplate
@@ -40,4 +89,56 @@ final class FileRules {
       return Files.readString(path);
     }
   }
+
+  /**
+   * Prefer {@link Files#createTempFile(String, String, FileAttribute[])} over alternatives that
+   * create files with more liberal permissions.
+   *
+   * <p>Note that {@link File#createTempFile} treats the given prefix as a path, and ignores all but
+   * its file name. That is, the actual prefix used is derived from all characters following the
+   * final file separator (if any). This is not the case with {@link Files#createTempFile}, which
+   * will instead throw an {@link IllegalArgumentException} if the prefix contains any file
+   * separators.
+   */
+  static final class FilesCreateTempFileToFile {
+    @BeforeTemplate
+    @SuppressWarnings({
+      "FilesCreateTempFileInCustomDirectoryToFile" /* This is a more specific template. */,
+      "java:S5443" /* This violation will be rewritten. */,
+      "key-to-resolve-AnnotationUseStyle-and-TrailingComment-check-conflict"
+    })
+    File before(String prefix, String suffix) throws IOException {
+      return Refaster.anyOf(
+          File.createTempFile(prefix, suffix), File.createTempFile(prefix, suffix, null));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings(
+        "java:S5443" /* On POSIX systems the file will only have user read-write permissions. */)
+    File after(String prefix, String suffix) throws IOException {
+      return Files.createTempFile(prefix, suffix).toFile();
+    }
+  }
+
+  /**
+   * Prefer {@link Files#createTempFile(Path, String, String, FileAttribute[])} over alternatives
+   * that create files with more liberal permissions.
+   *
+   * <p>Note that {@link File#createTempFile} treats the given prefix as a path, and ignores all but
+   * its file name. That is, the actual prefix used is derived from all characters following the
+   * final file separator (if any). This is not the case with {@link Files#createTempFile}, which
+   * will instead throw an {@link IllegalArgumentException} if the prefix contains any file
+   * separators.
+   */
+  static final class FilesCreateTempFileInCustomDirectoryToFile {
+    @BeforeTemplate
+    File before(File directory, String prefix, String suffix) throws IOException {
+      return File.createTempFile(prefix, suffix, directory);
+    }
+
+    @AfterTemplate
+    File after(File directory, String prefix, String suffix) throws IOException {
+      return Files.createTempFile(directory.toPath(), prefix, suffix).toFile();
+    }
+  }
 }

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

@@ -0,0 +1,246 @@
+package tech.picnic.errorprone.refasterrules;
+
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
+import static com.google.common.collect.Sets.toImmutableEnumSet;
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+
+import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Sets;
+import com.google.errorprone.refaster.Refaster;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.Repeated;
+import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.EnumSet;
+import java.util.stream.Stream;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/**
+ * Refaster rules related to expressions dealing with {@code
+ * com.google.common.collect.ImmutableEnumSet}s.
+ */
+// XXX: Some of the rules defined here impact iteration order. That's a rather subtle change. Should
+// we emit a comment warning about this fact? (This may produce a lot of noise. A bug checker could
+// in some cases determine whether iteration order is important.)
+// XXX: Consider replacing the `SetsImmutableEnumSet[N]` Refaster rules with a bug checker, such
+// that call to `ImmutableSet#of(Object, Object, Object, Object, Object, Object, Object[])` with
+// enum-typed values can also be rewritten.
+@OnlineDocumentation
+final class ImmutableEnumSetRules {
+  private ImmutableEnumSetRules() {}
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Iterable)} for enum collections to take advantage of the
+   * internally used {@link EnumSet}.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the
+   * original code produces a set that iterates over its elements in the same order as the input
+   * {@link Iterable}, the replacement code iterates over the elements in enum definition order.
+   */
+  static final class SetsImmutableEnumSetIterable<T extends Enum<T>> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Iterable<T> elements) {
+      return ImmutableSet.copyOf(elements);
+    }
+
+    @BeforeTemplate
+    ImmutableSet<T> before(Collection<T> elements) {
+      return ImmutableSet.copyOf(elements);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(Iterable<T> elements) {
+      return Sets.immutableEnumSet(elements);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Iterable)} for enum collections to take advantage of the
+   * internally used {@link EnumSet}.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the
+   * original code produces a set that iterates over its elements in the same order as defined in
+   * the array, the replacement code iterates over the elements in enum definition order.
+   */
+  static final class SetsImmutableEnumSetArraysAsList<T extends Enum<T>> {
+    @BeforeTemplate
+    ImmutableSet<T> before(T[] elements) {
+      return ImmutableSet.copyOf(elements);
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T[] elements) {
+      return Sets.immutableEnumSet(Arrays.asList(elements));
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * the internally used {@link EnumSet}.
+   */
+  static final class SetsImmutableEnumSet1<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("SetsImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1) {
+      return Refaster.anyOf(ImmutableSet.of(e1), ImmutableSet.copyOf(EnumSet.of(e1)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1) {
+      return Sets.immutableEnumSet(e1);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * the internally used {@link EnumSet}.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the {@link
+   * ImmutableSet#of} expression produces a set that iterates over its elements in the listed order,
+   * the replacement code iterates over the elements in enum definition order.
+   */
+  static final class SetsImmutableEnumSet2<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("SetsImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2) {
+      return Refaster.anyOf(ImmutableSet.of(e1, e2), ImmutableSet.copyOf(EnumSet.of(e1, e2)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2) {
+      return Sets.immutableEnumSet(e1, e2);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * the internally used {@link EnumSet}.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the {@link
+   * ImmutableSet#of} expression produces a set that iterates over its elements in the listed order,
+   * the replacement code iterates over the elements in enum definition order.
+   */
+  static final class SetsImmutableEnumSet3<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("SetsImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2, T e3) {
+      return Refaster.anyOf(
+          ImmutableSet.of(e1, e2, e3), ImmutableSet.copyOf(EnumSet.of(e1, e2, e3)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3) {
+      return Sets.immutableEnumSet(e1, e2, e3);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * the internally used {@link EnumSet}.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the {@link
+   * ImmutableSet#of} expression produces a set that iterates over its elements in the listed order,
+   * the replacement code iterates over the elements in enum definition order.
+   */
+  static final class SetsImmutableEnumSet4<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("SetsImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2, T e3, T e4) {
+      return Refaster.anyOf(
+          ImmutableSet.of(e1, e2, e3, e4), ImmutableSet.copyOf(EnumSet.of(e1, e2, e3, e4)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4) {
+      return Sets.immutableEnumSet(e1, e2, e3, e4);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * the internally used {@link EnumSet}.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the {@link
+   * ImmutableSet#of} expression produces a set that iterates over its elements in the listed order,
+   * the replacement code iterates over the elements in enum definition order.
+   */
+  static final class SetsImmutableEnumSet5<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("SetsImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, T e2, T e3, T e4, T e5) {
+      return Refaster.anyOf(
+          ImmutableSet.of(e1, e2, e3, e4, e5), ImmutableSet.copyOf(EnumSet.of(e1, e2, e3, e4, e5)));
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4, T e5) {
+      return Sets.immutableEnumSet(e1, e2, e3, e4, e5);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * the internally used {@link EnumSet}.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the
+   * original code produces a set that iterates over its elements in the listed order, the
+   * replacement code iterates over the elements in enum definition order.
+   */
+  static final class SetsImmutableEnumSet6<T extends Enum<T>> {
+    @BeforeTemplate
+    ImmutableSet<T> before(T e1, T e2, T e3, T e4, T e5, T e6) {
+      return ImmutableSet.of(e1, e2, e3, e4, e5, e6);
+    }
+
+    @AfterTemplate
+    @SuppressWarnings("unchecked")
+    ImmutableSet<T> after(T e1, T e2, T e3, T e4, T e5, T e6) {
+      return Sets.immutableEnumSet(e1, e2, e3, e4, e5, e6);
+    }
+  }
+
+  /**
+   * Prefer {@link Sets#immutableEnumSet(Enum, Enum[])} for enum collections to take advantage of
+   * the internally used {@link EnumSet}.
+   */
+  static final class SetsImmutableEnumSetVarArgs<T extends Enum<T>> {
+    @BeforeTemplate
+    @SuppressWarnings("SetsImmutableEnumSetIterable" /* This is a more specific template. */)
+    ImmutableSet<T> before(T e1, @Repeated T elements) {
+      return ImmutableSet.copyOf(EnumSet.of(e1, Refaster.asVarargs(elements)));
+    }
+
+    @AfterTemplate
+    ImmutableSet<T> after(T e1, @Repeated T elements) {
+      return Sets.immutableEnumSet(e1, Refaster.asVarargs(elements));
+    }
+  }
+
+  /**
+   * Use {@link Sets#toImmutableEnumSet()} when possible, as it is more efficient than {@link
+   * ImmutableSet#toImmutableSet()} and produces a more compact object.
+   *
+   * <p><strong>Warning:</strong> this rule is not completely behavior preserving: while the
+   * original code produces a set that iterates over its elements in encounter order, the
+   * replacement code iterates over the elements in enum definition order.
+   */
+  static final class StreamToImmutableEnumSet<T extends Enum<T>> {
+    @BeforeTemplate
+    ImmutableSet<T> before(Stream<T> stream) {
+      return stream.collect(toImmutableSet());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    ImmutableSet<T> after(Stream<T> stream) {
+      return stream.collect(toImmutableEnumSet());
+    }
+  }
+}

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

@@ -36,8 +36,7 @@ final class ImmutableListMultimapRules {
    * Prefer {@link ImmutableListMultimap#builder()} over the associated constructor on constructions
    * that produce a less-specific type.
    */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableListMultimapBuilder<K, V> {
     @BeforeTemplate
     ImmutableMultimap.Builder<K, V> before() {

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

@@ -28,8 +28,7 @@ final class ImmutableListRules {
   private ImmutableListRules() {}
 
   /** Prefer {@link ImmutableList#builder()} over the associated constructor. */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableListBuilder<T> {
     @BeforeTemplate
     ImmutableList.Builder<T> before() {

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

@@ -31,8 +31,7 @@ final class ImmutableMapRules {
   private ImmutableMapRules() {}
 
   /** Prefer {@link ImmutableMap#builder()} over the associated constructor. */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableMapBuilder<K, V> {
     @BeforeTemplate
     ImmutableMap.Builder<K, V> before() {

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

@@ -21,8 +21,7 @@ final class ImmutableMultisetRules {
   private ImmutableMultisetRules() {}
 
   /** Prefer {@link ImmutableMultiset#builder()} over the associated constructor. */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableMultisetBuilder<T> {
     @BeforeTemplate
     ImmutableMultiset.Builder<T> before() {

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

@@ -29,8 +29,7 @@ final class ImmutableSetMultimapRules {
   private ImmutableSetMultimapRules() {}
 
   /** Prefer {@link ImmutableSetMultimap#builder()} over the associated constructor. */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableSetMultimapBuilder<K, V> {
     @BeforeTemplate
     ImmutableSetMultimap.Builder<K, V> before() {

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

@@ -29,8 +29,7 @@ final class ImmutableSetRules {
   private ImmutableSetRules() {}
 
   /** Prefer {@link ImmutableSet#builder()} over the associated constructor. */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableSetBuilder<T> {
     @BeforeTemplate
     ImmutableSet.Builder<T> before() {

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

@@ -37,8 +37,7 @@ final class ImmutableSortedMapRules {
    * Prefer {@link ImmutableSortedMap#naturalOrder()} over the alternative that requires explicitly
    * providing the {@link Comparator}.
    */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableSortedMapNaturalOrderBuilder<K extends Comparable<? super K>, V> {
     @BeforeTemplate
     ImmutableSortedMap.Builder<K, V> before() {
@@ -55,8 +54,7 @@ final class ImmutableSortedMapRules {
    * Prefer {@link ImmutableSortedMap#reverseOrder()} over the alternative that requires explicitly
    * providing the {@link Comparator}.
    */
-  // XXX: This drops generic type information, sometimes leading to non-compilable code. See
-  // https://github.com/google/error-prone/pull/2706.
+  // XXX: This rule may drop generic type information, leading to non-compilable code.
   static final class ImmutableSortedMapReverseOrderBuilder<K extends Comparable<? super K>, V> {
     @BeforeTemplate
     ImmutableSortedMap.Builder<K, V> before() {

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

@@ -9,8 +9,6 @@ import java.io.OutputStream;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 
 /** Refaster rules related to expressions dealing with {@link InputStream}s. */
-// XXX: Add a rule for `ByteStreams.skipFully(in, n)` -> `in.skipNBytes(n)` once we have a way to
-// target JDK 12+ APIs.
 @OnlineDocumentation
 final class InputStreamRules {
   private InputStreamRules() {}
@@ -38,4 +36,28 @@ final class InputStreamRules {
       return in.readAllBytes();
     }
   }
+
+  static final class InputStreamReadNBytes {
+    @BeforeTemplate
+    byte[] before(InputStream in, int n) throws IOException {
+      return ByteStreams.limit(in, n).readAllBytes();
+    }
+
+    @AfterTemplate
+    byte[] after(InputStream in, int n) throws IOException {
+      return in.readNBytes(n);
+    }
+  }
+
+  static final class InputStreamSkipNBytes {
+    @BeforeTemplate
+    void before(InputStream in, long n) throws IOException {
+      ByteStreams.skipFully(in, n);
+    }
+
+    @AfterTemplate
+    void after(InputStream in, long n) throws IOException {
+      in.skipNBytes(n);
+    }
+  }
 }

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

@@ -26,6 +26,7 @@ import org.junit.jupiter.api.Assertions;
 import org.junit.jupiter.api.function.Executable;
 import org.junit.jupiter.api.function.ThrowingSupplier;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.annotation.TypeMigration;
 
 /**
  * Refaster rules to replace JUnit assertions with AssertJ equivalents.
@@ -40,19 +41,283 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
 // `() -> toString()` match both `ThrowingSupplier` and `ThrowingCallable`, but `() -> "constant"`
 // is only compatible with the former.
 @OnlineDocumentation
+@TypeMigration(
+    of = Assertions.class,
+    unmigratedMethods = {
+      "assertAll(Collection<Executable>)",
+      "assertAll(Executable[])",
+      "assertAll(Stream<Executable>)",
+      "assertAll(String, Collection<Executable>)",
+      "assertAll(String, Executable[])",
+      "assertAll(String, Stream<Executable>)",
+      "assertArrayEquals(boolean[], boolean[])",
+      "assertArrayEquals(boolean[], boolean[], String)",
+      "assertArrayEquals(boolean[], boolean[], Supplier<String>)",
+      "assertArrayEquals(byte[], byte[])",
+      "assertArrayEquals(byte[], byte[], String)",
+      "assertArrayEquals(byte[], byte[], Supplier<String>)",
+      "assertArrayEquals(char[], char[])",
+      "assertArrayEquals(char[], char[], String)",
+      "assertArrayEquals(char[], char[], Supplier<String>)",
+      "assertArrayEquals(double[], double[])",
+      "assertArrayEquals(double[], double[], double)",
+      "assertArrayEquals(double[], double[], double, String)",
+      "assertArrayEquals(double[], double[], double, Supplier<String>)",
+      "assertArrayEquals(double[], double[], String)",
+      "assertArrayEquals(double[], double[], Supplier<String>)",
+      "assertArrayEquals(float[], float[])",
+      "assertArrayEquals(float[], float[], float)",
+      "assertArrayEquals(float[], float[], float, String)",
+      "assertArrayEquals(float[], float[], float, Supplier<String>)",
+      "assertArrayEquals(float[], float[], String)",
+      "assertArrayEquals(float[], float[], Supplier<String>)",
+      "assertArrayEquals(int[], int[])",
+      "assertArrayEquals(int[], int[], String)",
+      "assertArrayEquals(int[], int[], Supplier<String>)",
+      "assertArrayEquals(long[], long[])",
+      "assertArrayEquals(long[], long[], String)",
+      "assertArrayEquals(long[], long[], Supplier<String>)",
+      "assertArrayEquals(Object[], Object[])",
+      "assertArrayEquals(Object[], Object[], String)",
+      "assertArrayEquals(Object[], Object[], Supplier<String>)",
+      "assertArrayEquals(short[], short[])",
+      "assertArrayEquals(short[], short[], String)",
+      "assertArrayEquals(short[], short[], Supplier<String>)",
+      "assertEquals(Byte, Byte)",
+      "assertEquals(Byte, byte)",
+      "assertEquals(byte, Byte)",
+      "assertEquals(byte, byte)",
+      "assertEquals(Byte, Byte, String)",
+      "assertEquals(Byte, byte, String)",
+      "assertEquals(byte, Byte, String)",
+      "assertEquals(byte, byte, String)",
+      "assertEquals(Byte, Byte, Supplier<String>)",
+      "assertEquals(Byte, byte, Supplier<String>)",
+      "assertEquals(byte, Byte, Supplier<String>)",
+      "assertEquals(byte, byte, Supplier<String>)",
+      "assertEquals(char, char)",
+      "assertEquals(char, char, String)",
+      "assertEquals(char, char, Supplier<String>)",
+      "assertEquals(char, Character)",
+      "assertEquals(char, Character, String)",
+      "assertEquals(char, Character, Supplier<String>)",
+      "assertEquals(Character, char)",
+      "assertEquals(Character, char, String)",
+      "assertEquals(Character, char, Supplier<String>)",
+      "assertEquals(Character, Character)",
+      "assertEquals(Character, Character, String)",
+      "assertEquals(Character, Character, Supplier<String>)",
+      "assertEquals(Double, Double)",
+      "assertEquals(Double, double)",
+      "assertEquals(double, Double)",
+      "assertEquals(double, double)",
+      "assertEquals(double, double, double)",
+      "assertEquals(double, double, double, String)",
+      "assertEquals(double, double, double, Supplier<String>)",
+      "assertEquals(Double, Double, String)",
+      "assertEquals(Double, double, String)",
+      "assertEquals(double, Double, String)",
+      "assertEquals(double, double, String)",
+      "assertEquals(Double, Double, Supplier<String>)",
+      "assertEquals(Double, double, Supplier<String>)",
+      "assertEquals(double, Double, Supplier<String>)",
+      "assertEquals(double, double, Supplier<String>)",
+      "assertEquals(Float, Float)",
+      "assertEquals(Float, float)",
+      "assertEquals(float, Float)",
+      "assertEquals(float, float)",
+      "assertEquals(float, float, float)",
+      "assertEquals(float, float, float, String)",
+      "assertEquals(float, float, float, Supplier<String>)",
+      "assertEquals(Float, Float, String)",
+      "assertEquals(Float, float, String)",
+      "assertEquals(float, Float, String)",
+      "assertEquals(float, float, String)",
+      "assertEquals(Float, Float, Supplier<String>)",
+      "assertEquals(Float, float, Supplier<String>)",
+      "assertEquals(float, Float, Supplier<String>)",
+      "assertEquals(float, float, Supplier<String>)",
+      "assertEquals(int, int)",
+      "assertEquals(int, int, String)",
+      "assertEquals(int, int, Supplier<String>)",
+      "assertEquals(int, Integer)",
+      "assertEquals(int, Integer, String)",
+      "assertEquals(int, Integer, Supplier<String>)",
+      "assertEquals(Integer, int)",
+      "assertEquals(Integer, int, String)",
+      "assertEquals(Integer, int, Supplier<String>)",
+      "assertEquals(Integer, Integer)",
+      "assertEquals(Integer, Integer, String)",
+      "assertEquals(Integer, Integer, Supplier<String>)",
+      "assertEquals(Long, Long)",
+      "assertEquals(Long, long)",
+      "assertEquals(long, Long)",
+      "assertEquals(long, long)",
+      "assertEquals(Long, Long, String)",
+      "assertEquals(Long, long, String)",
+      "assertEquals(long, Long, String)",
+      "assertEquals(long, long, String)",
+      "assertEquals(Long, Long, Supplier<String>)",
+      "assertEquals(Long, long, Supplier<String>)",
+      "assertEquals(long, Long, Supplier<String>)",
+      "assertEquals(long, long, Supplier<String>)",
+      "assertEquals(Object, Object)",
+      "assertEquals(Object, Object, String)",
+      "assertEquals(Object, Object, Supplier<String>)",
+      "assertEquals(Short, Short)",
+      "assertEquals(Short, short)",
+      "assertEquals(short, Short)",
+      "assertEquals(short, short)",
+      "assertEquals(Short, Short, String)",
+      "assertEquals(Short, short, String)",
+      "assertEquals(short, Short, String)",
+      "assertEquals(short, short, String)",
+      "assertEquals(Short, Short, Supplier<String>)",
+      "assertEquals(Short, short, Supplier<String>)",
+      "assertEquals(short, Short, Supplier<String>)",
+      "assertEquals(short, short, Supplier<String>)",
+      "assertFalse(BooleanSupplier)",
+      "assertFalse(BooleanSupplier, String)",
+      "assertFalse(BooleanSupplier, Supplier<String>)",
+      "assertIterableEquals(Iterable<?>, Iterable<?>)",
+      "assertIterableEquals(Iterable<?>, Iterable<?>, String)",
+      "assertIterableEquals(Iterable<?>, Iterable<?>, Supplier<String>)",
+      "assertLinesMatch(List<String>, List<String>)",
+      "assertLinesMatch(List<String>, List<String>, String)",
+      "assertLinesMatch(List<String>, List<String>, Supplier<String>)",
+      "assertLinesMatch(Stream<String>, Stream<String>)",
+      "assertLinesMatch(Stream<String>, Stream<String>, String)",
+      "assertLinesMatch(Stream<String>, Stream<String>, Supplier<String>)",
+      "assertNotEquals(Byte, Byte)",
+      "assertNotEquals(Byte, byte)",
+      "assertNotEquals(byte, Byte)",
+      "assertNotEquals(byte, byte)",
+      "assertNotEquals(Byte, Byte, String)",
+      "assertNotEquals(Byte, byte, String)",
+      "assertNotEquals(byte, Byte, String)",
+      "assertNotEquals(byte, byte, String)",
+      "assertNotEquals(Byte, Byte, Supplier<String>)",
+      "assertNotEquals(Byte, byte, Supplier<String>)",
+      "assertNotEquals(byte, Byte, Supplier<String>)",
+      "assertNotEquals(byte, byte, Supplier<String>)",
+      "assertNotEquals(char, char)",
+      "assertNotEquals(char, char, String)",
+      "assertNotEquals(char, char, Supplier<String>)",
+      "assertNotEquals(char, Character)",
+      "assertNotEquals(char, Character, String)",
+      "assertNotEquals(char, Character, Supplier<String>)",
+      "assertNotEquals(Character, char)",
+      "assertNotEquals(Character, char, String)",
+      "assertNotEquals(Character, char, Supplier<String>)",
+      "assertNotEquals(Character, Character)",
+      "assertNotEquals(Character, Character, String)",
+      "assertNotEquals(Character, Character, Supplier<String>)",
+      "assertNotEquals(Double, Double)",
+      "assertNotEquals(Double, double)",
+      "assertNotEquals(double, Double)",
+      "assertNotEquals(double, double)",
+      "assertNotEquals(double, double, double)",
+      "assertNotEquals(double, double, double, String)",
+      "assertNotEquals(double, double, double, Supplier<String>)",
+      "assertNotEquals(Double, Double, String)",
+      "assertNotEquals(Double, double, String)",
+      "assertNotEquals(double, Double, String)",
+      "assertNotEquals(double, double, String)",
+      "assertNotEquals(Double, Double, Supplier<String>)",
+      "assertNotEquals(Double, double, Supplier<String>)",
+      "assertNotEquals(double, Double, Supplier<String>)",
+      "assertNotEquals(double, double, Supplier<String>)",
+      "assertNotEquals(Float, Float)",
+      "assertNotEquals(Float, float)",
+      "assertNotEquals(float, Float)",
+      "assertNotEquals(float, float)",
+      "assertNotEquals(float, float, float)",
+      "assertNotEquals(float, float, float, String)",
+      "assertNotEquals(float, float, float, Supplier<String>)",
+      "assertNotEquals(Float, Float, String)",
+      "assertNotEquals(Float, float, String)",
+      "assertNotEquals(float, Float, String)",
+      "assertNotEquals(float, float, String)",
+      "assertNotEquals(Float, Float, Supplier<String>)",
+      "assertNotEquals(Float, float, Supplier<String>)",
+      "assertNotEquals(float, Float, Supplier<String>)",
+      "assertNotEquals(float, float, Supplier<String>)",
+      "assertNotEquals(int, int)",
+      "assertNotEquals(int, int, String)",
+      "assertNotEquals(int, int, Supplier<String>)",
+      "assertNotEquals(int, Integer)",
+      "assertNotEquals(int, Integer, String)",
+      "assertNotEquals(int, Integer, Supplier<String>)",
+      "assertNotEquals(Integer, int)",
+      "assertNotEquals(Integer, int, String)",
+      "assertNotEquals(Integer, int, Supplier<String>)",
+      "assertNotEquals(Integer, Integer)",
+      "assertNotEquals(Integer, Integer, String)",
+      "assertNotEquals(Integer, Integer, Supplier<String>)",
+      "assertNotEquals(Long, Long)",
+      "assertNotEquals(Long, long)",
+      "assertNotEquals(long, Long)",
+      "assertNotEquals(long, long)",
+      "assertNotEquals(Long, Long, String)",
+      "assertNotEquals(Long, long, String)",
+      "assertNotEquals(long, Long, String)",
+      "assertNotEquals(long, long, String)",
+      "assertNotEquals(Long, Long, Supplier<String>)",
+      "assertNotEquals(Long, long, Supplier<String>)",
+      "assertNotEquals(long, Long, Supplier<String>)",
+      "assertNotEquals(long, long, Supplier<String>)",
+      "assertNotEquals(Object, Object)",
+      "assertNotEquals(Object, Object, String)",
+      "assertNotEquals(Object, Object, Supplier<String>)",
+      "assertNotEquals(Short, Short)",
+      "assertNotEquals(Short, short)",
+      "assertNotEquals(short, Short)",
+      "assertNotEquals(short, short)",
+      "assertNotEquals(Short, Short, String)",
+      "assertNotEquals(Short, short, String)",
+      "assertNotEquals(short, Short, String)",
+      "assertNotEquals(short, short, String)",
+      "assertNotEquals(Short, Short, Supplier<String>)",
+      "assertNotEquals(Short, short, Supplier<String>)",
+      "assertNotEquals(short, Short, Supplier<String>)",
+      "assertNotEquals(short, short, Supplier<String>)",
+      "assertTimeout(Duration, Executable)",
+      "assertTimeout(Duration, Executable, String)",
+      "assertTimeout(Duration, Executable, Supplier<String>)",
+      "assertTimeout(Duration, ThrowingSupplier<T>)",
+      "assertTimeout(Duration, ThrowingSupplier<T>, String)",
+      "assertTimeout(Duration, ThrowingSupplier<T>, Supplier<String>)",
+      "assertTimeoutPreemptively(Duration, Executable)",
+      "assertTimeoutPreemptively(Duration, Executable, String)",
+      "assertTimeoutPreemptively(Duration, Executable, Supplier<String>)",
+      "assertTimeoutPreemptively(Duration, ThrowingSupplier<T>)",
+      "assertTimeoutPreemptively(Duration, ThrowingSupplier<T>, String)",
+      "assertTimeoutPreemptively(Duration, ThrowingSupplier<T>, Supplier<String>)",
+      "assertTimeoutPreemptively(Duration, ThrowingSupplier<T>, Supplier<String>, TimeoutFailureFactory<E>)",
+      "assertTrue(BooleanSupplier)",
+      "assertTrue(BooleanSupplier, String)",
+      "assertTrue(BooleanSupplier, Supplier<String>)",
+      "fail(Supplier<String>)"
+    })
 final class JUnitToAssertJRules {
   private JUnitToAssertJRules() {}
 
-  static final class ThrowNewAssertionError {
+  static final class Fail<T> {
     @BeforeTemplate
-    void before() {
-      Assertions.fail();
+    T before() {
+      return Assertions.fail();
     }
 
+    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)` once
+    // https://github.com/google/error-prone/pull/3584 is resolved. Until that time, statically
+    // importing AssertJ's `fail` is likely to clash with an existing static import of JUnit's
+    // `fail`. Note that combining Error Prone's `RemoveUnusedImports` and
+    // `UnnecessarilyFullyQualified` checks and our `StaticImport` check will anyway cause the
+    // method to be imported statically if possible; just in a less efficient manner.
     @AfterTemplate
     @DoNotCall
-    void after() {
-      throw new AssertionError();
+    T after() {
+      return fail();
     }
   }
 
@@ -62,12 +327,7 @@ final class JUnitToAssertJRules {
       return Assertions.fail(message);
     }
 
-    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)` once
-    // https://github.com/google/error-prone/pull/3584 is resolved. Until that time, statically
-    // importing AssertJ's `fail` is likely to clash with an existing static import of JUnit's
-    // `fail`. Note that combining Error Prone's `RemoveUnusedImports` and
-    // `UnnecessarilyFullyQualified` checks and our `StaticImport` check will anyway cause the
-    // method to be imported statically if possible; just in a less efficient manner.
+    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)`. See `Fail` comment.
     @AfterTemplate
     T after(String message) {
       return fail(message);
@@ -80,28 +340,24 @@ final class JUnitToAssertJRules {
       return Assertions.fail(message, throwable);
     }
 
-    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)` once
-    // https://github.com/google/error-prone/pull/3584 is resolved. Until that time, statically
-    // importing AssertJ's `fail` is likely to clash with an existing static import of JUnit's
-    // `fail`. Note that combining Error Prone's `RemoveUnusedImports` and
-    // `UnnecessarilyFullyQualified` checks and our `StaticImport` check will anyway cause the
-    // method to be imported statically if possible; just in a less efficient manner.
+    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)`. See `Fail` comment.
     @AfterTemplate
     T after(String message, Throwable throwable) {
       return fail(message, throwable);
     }
   }
 
-  static final class FailWithThrowable {
+  static final class FailWithThrowable<T> {
     @BeforeTemplate
-    void before(Throwable throwable) {
-      Assertions.fail(throwable);
+    T before(Throwable throwable) {
+      return Assertions.fail(throwable);
     }
 
+    // XXX: Add `@UseImportPolicy(STATIC_IMPORT_ALWAYS)`. See `Fail` comment.
     @AfterTemplate
     @DoNotCall
-    void after(Throwable throwable) {
-      throw new AssertionError(throwable);
+    T after(Throwable throwable) {
+      return fail(throwable);
     }
   }
 

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

@@ -0,0 +1,88 @@
+package tech.picnic.errorprone.refasterrules;
+
+import com.google.common.collect.ImmutableCollection;
+import com.google.common.collect.ImmutableList;
+import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.refaster.Refaster;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.Tags;
+import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+
+/** Refaster rules related to expressions dealing with Micrometer. */
+// XXX: Consider replacing the `TagsOf[N]` rules with a bug checker, so that various other
+// expressions (e.g. those creating other collection types, those passing in tags some other way, or
+// those passing in more tags) can be replaced as wel.
+@OnlineDocumentation
+final class MicrometerRules {
+  private MicrometerRules() {}
+
+  /** Prefer using {@link Tags} over other immutable collections. */
+  static final class TagsOf1 {
+    @BeforeTemplate
+    ImmutableCollection<Tag> before(Tag tag) {
+      return Refaster.anyOf(ImmutableSet.of(tag), ImmutableList.of(tag));
+    }
+
+    @AfterTemplate
+    Iterable<Tag> after(Tag tag) {
+      return Tags.of(tag);
+    }
+  }
+
+  /** Prefer using {@link Tags} over other immutable collections. */
+  static final class TagsOf2 {
+    @BeforeTemplate
+    ImmutableCollection<Tag> before(Tag tag1, Tag tag2) {
+      return Refaster.anyOf(ImmutableSet.of(tag1, tag2), ImmutableList.of(tag1, tag2));
+    }
+
+    @AfterTemplate
+    Iterable<Tag> after(Tag tag1, Tag tag2) {
+      return Tags.of(tag1, tag2);
+    }
+  }
+
+  /** Prefer using {@link Tags} over other immutable collections. */
+  static final class TagsOf3 {
+    @BeforeTemplate
+    ImmutableCollection<Tag> before(Tag tag1, Tag tag2, Tag tag3) {
+      return Refaster.anyOf(ImmutableSet.of(tag1, tag2, tag3), ImmutableList.of(tag1, tag2, tag3));
+    }
+
+    @AfterTemplate
+    Iterable<Tag> after(Tag tag1, Tag tag2, Tag tag3) {
+      return Tags.of(tag1, tag2, tag3);
+    }
+  }
+
+  /** Prefer using {@link Tags} over other immutable collections. */
+  static final class TagsOf4 {
+    @BeforeTemplate
+    ImmutableCollection<Tag> before(Tag tag1, Tag tag2, Tag tag3, Tag tag4) {
+      return Refaster.anyOf(
+          ImmutableSet.of(tag1, tag2, tag3, tag4), ImmutableList.of(tag1, tag2, tag3, tag4));
+    }
+
+    @AfterTemplate
+    Iterable<Tag> after(Tag tag1, Tag tag2, Tag tag3, Tag tag4) {
+      return Tags.of(tag1, tag2, tag3, tag4);
+    }
+  }
+
+  /** Prefer using {@link Tags} over other immutable collections. */
+  static final class TagsOf5 {
+    @BeforeTemplate
+    ImmutableCollection<Tag> before(Tag tag1, Tag tag2, Tag tag3, Tag tag4, Tag tag5) {
+      return Refaster.anyOf(
+          ImmutableSet.of(tag1, tag2, tag3, tag4, tag5),
+          ImmutableList.of(tag1, tag2, tag3, tag4, tag5));
+    }
+
+    @AfterTemplate
+    Iterable<Tag> after(Tag tag1, Tag tag2, Tag tag3, Tag tag4, Tag tag5) {
+      return Tags.of(tag1, tag2, tag3, tag4, tag5);
+    }
+  }
+}

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

@@ -20,13 +20,26 @@ import java.util.function.Supplier;
 import java.util.stream.Stream;
 import org.jspecify.annotations.Nullable;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
-import tech.picnic.errorprone.refaster.matchers.IsLikelyTrivialComputation;
+import tech.picnic.errorprone.refaster.matchers.RequiresComputation;
 
 /** Refaster rules related to expressions dealing with {@link Optional}s. */
 @OnlineDocumentation
 final class OptionalRules {
   private OptionalRules() {}
 
+  /** Prefer {@link Optional#empty()} over the more contrived alternative. */
+  static final class OptionalEmpty<T> {
+    @BeforeTemplate
+    Optional<T> before() {
+      return Optional.ofNullable(null);
+    }
+
+    @AfterTemplate
+    Optional<T> after() {
+      return Optional.empty();
+    }
+  }
+
   static final class OptionalOfNullable<T> {
     // XXX: Refaster should be smart enough to also rewrite occurrences in which there are
     // parentheses around the null check, but that's currently not the case. Try to fix that.
@@ -242,24 +255,21 @@ final class OptionalRules {
   }
 
   /**
-   * Prefer {@link Optional#orElseGet(Supplier)} over {@link Optional#orElse(Object)} if the
-   * fallback value is not the result of a trivial computation.
+   * Prefer {@link Optional#orElse(Object)} over {@link Optional#orElseGet(Supplier)} if the
+   * fallback value does not require non-trivial computation.
    */
-  // XXX: This rule may introduce a compilation error: the `value` expression may reference a
-  // non-effectively final variable, which is not allowed in the replacement lambda expression.
-  // Review whether a `@Matcher` can be used to avoid this.
-  // XXX: Once `MethodReferenceUsage` is "production ready", replace
-  // `@NotMatches(IsLikelyTrivialComputation.class)` with `@Matches(RequiresComputation.class)` (and
-  // reimplement the matcher accordingly).
-  static final class OptionalOrElseGet<T> {
+  // XXX: This rule is the counterpart to the `OptionalOrElseGet` bug checker. Once the
+  // `MethodReferenceUsage` bug checker is "production ready", that bug checker may similarly be
+  // replaced with a Refaster rule.
+  static final class OptionalOrElse<T> {
     @BeforeTemplate
-    T before(Optional<T> optional, @NotMatches(IsLikelyTrivialComputation.class) T value) {
-      return optional.orElse(value);
+    T before(Optional<T> optional, @NotMatches(RequiresComputation.class) T value) {
+      return optional.orElseGet(() -> value);
     }
 
     @AfterTemplate
     T after(Optional<T> optional, T value) {
-      return optional.orElseGet(() -> value);
+      return optional.orElse(value);
     }
   }
 
@@ -269,6 +279,9 @@ final class OptionalRules {
    */
   // XXX: Do we need the `.filter(Optional::isPresent)`? If it's absent the caller probably assumed
   // that the values are present. (If we drop it, we should rewrite vacuous filter steps.)
+  // XXX: The rewritten `filter`/`map` expression may be more performant than its replacement. See
+  // https://github.com/palantir/gradle-baseline/pull/2946. (There are plans to pair Refaster rules
+  // with JMH benchmarks; this would be a great use case.)
   static final class StreamFlatMapOptional<T> {
     @BeforeTemplate
     Stream<T> before(Stream<Optional<T>> stream) {
@@ -360,7 +373,12 @@ final class OptionalRules {
   /** Prefer {@link Optional#or(Supplier)} over more verbose alternatives. */
   static final class OptionalOrOtherOptional<T> {
     @BeforeTemplate
-    @SuppressWarnings("NestedOptionals" /* Auto-fix for the `NestedOptionals` check. */)
+    @SuppressWarnings({
+      "LexicographicalAnnotationAttributeListing" /* `key-*` entry must remain last. */,
+      "NestedOptionals" /* This violation will be rewritten. */,
+      "OptionalOrElse" /* Parameters represent expressions that may require computation. */,
+      "key-to-resolve-AnnotationUseStyle-and-TrailingComment-check-conflict"
+    })
     Optional<T> before(Optional<T> optional1, Optional<T> optional2) {
       // XXX: Note that rewriting the first and third variant will change the code's behavior if
       // `optional2` has side-effects.
@@ -380,15 +398,16 @@ final class OptionalRules {
     }
   }
 
-  /**
-   * Avoid unnecessary operations on an {@link Optional} that ultimately result in that very same
-   * {@link Optional}.
-   */
+  /** Don't unnecessarily transform an {@link Optional} to an equivalent instance. */
   static final class OptionalIdentity<T> {
     @BeforeTemplate
+    @SuppressWarnings("NestedOptionals")
     Optional<T> before(Optional<T> optional, Comparator<? super T> comparator) {
       return Refaster.anyOf(
           optional.or(Refaster.anyOf(() -> Optional.empty(), Optional::empty)),
+          optional
+              .map(Optional::of)
+              .orElseGet(Refaster.anyOf(() -> Optional.empty(), Optional::empty)),
           optional.stream().findFirst(),
           optional.stream().findAny(),
           optional.stream().min(comparator),
@@ -442,9 +461,7 @@ final class OptionalRules {
   static final class OptionalStream<T> {
     @BeforeTemplate
     Stream<T> before(Optional<T> optional) {
-      return Refaster.anyOf(
-          optional.map(Stream::of).orElse(Stream.empty()),
-          optional.map(Stream::of).orElseGet(Stream::empty));
+      return optional.map(Stream::of).orElseGet(Stream::empty);
     }
 
     @AfterTemplate

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

@@ -8,6 +8,8 @@ import com.google.common.primitives.Floats;
 import com.google.common.primitives.Ints;
 import com.google.common.primitives.Longs;
 import com.google.common.primitives.Shorts;
+import com.google.common.primitives.UnsignedInts;
+import com.google.common.primitives.UnsignedLongs;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.AlsoNegation;
@@ -76,6 +78,8 @@ final class PrimitiveRules {
   }
 
   /** Prefer {@link Math#toIntExact(long)} over the Guava alternative. */
+  // XXX: This rule changes the exception possibly thrown from `IllegalArgumentException` to
+  // `ArithmeticException`.
   static final class LongToIntExact {
     @BeforeTemplate
     int before(long l) {
@@ -192,97 +196,6 @@ final class PrimitiveRules {
     }
   }
 
-  /** Prefer {@link Boolean#compare(boolean, boolean)} over the Guava alternative. */
-  static final class BooleanCompare {
-    @BeforeTemplate
-    int before(boolean a, boolean b) {
-      return Booleans.compare(a, b);
-    }
-
-    @AfterTemplate
-    int after(boolean a, boolean b) {
-      return Boolean.compare(a, b);
-    }
-  }
-
-  /** Prefer {@link Character#compare(char, char)} over the Guava alternative. */
-  static final class CharacterCompare {
-    @BeforeTemplate
-    int before(char a, char b) {
-      return Chars.compare(a, b);
-    }
-
-    @AfterTemplate
-    int after(char a, char b) {
-      return Character.compare(a, b);
-    }
-  }
-
-  /** Prefer {@link Short#compare(short, short)} over the Guava alternative. */
-  static final class ShortCompare {
-    @BeforeTemplate
-    int before(short a, short b) {
-      return Shorts.compare(a, b);
-    }
-
-    @AfterTemplate
-    int after(short a, short b) {
-      return Short.compare(a, b);
-    }
-  }
-
-  /** Prefer {@link Integer#compare(int, int)} over the Guava alternative. */
-  static final class IntegerCompare {
-    @BeforeTemplate
-    int before(int a, int b) {
-      return Ints.compare(a, b);
-    }
-
-    @AfterTemplate
-    int after(int a, int b) {
-      return Integer.compare(a, b);
-    }
-  }
-
-  /** Prefer {@link Long#compare(long, long)} over the Guava alternative. */
-  static final class LongCompare {
-    @BeforeTemplate
-    int before(long a, long b) {
-      return Longs.compare(a, b);
-    }
-
-    @AfterTemplate
-    int after(long a, long b) {
-      return Long.compare(a, b);
-    }
-  }
-
-  /** Prefer {@link Float#compare(float, float)} over the Guava alternative. */
-  static final class FloatCompare {
-    @BeforeTemplate
-    int before(float a, float b) {
-      return Floats.compare(a, b);
-    }
-
-    @AfterTemplate
-    int after(float a, float b) {
-      return Float.compare(a, b);
-    }
-  }
-
-  /** Prefer {@link Double#compare(double, double)} over the Guava alternative. */
-  static final class DoubleCompare {
-    @BeforeTemplate
-    int before(double a, double b) {
-      return Doubles.compare(a, b);
-    }
-
-    @AfterTemplate
-    int after(double a, double b) {
-      return Double.compare(a, b);
-    }
-  }
-
   /** Prefer {@link Character#BYTES} over the Guava alternative. */
   static final class CharacterBytes {
     @BeforeTemplate
@@ -442,4 +355,205 @@ final class PrimitiveRules {
       return Long.signum(l) == -1;
     }
   }
+
+  /** Prefer JDK's {@link Integer#compareUnsigned(int, int)} over third-party alternatives. */
+  static final class IntegerCompareUnsigned {
+    @BeforeTemplate
+    int before(int x, int y) {
+      return UnsignedInts.compare(x, y);
+    }
+
+    @AfterTemplate
+    int after(int x, int y) {
+      return Integer.compareUnsigned(x, y);
+    }
+  }
+
+  /** Prefer JDK's {@link Long#compareUnsigned(long, long)} over third-party alternatives. */
+  static final class LongCompareUnsigned {
+    @BeforeTemplate
+    long before(long x, long y) {
+      return UnsignedLongs.compare(x, y);
+    }
+
+    @AfterTemplate
+    long after(long x, long y) {
+      return Long.compareUnsigned(x, y);
+    }
+  }
+
+  /** Prefer JDK's {@link Integer#divideUnsigned(int, int)} over third-party alternatives. */
+  static final class IntegerDivideUnsigned {
+    @BeforeTemplate
+    int before(int x, int y) {
+      return UnsignedInts.divide(x, y);
+    }
+
+    @AfterTemplate
+    int after(int x, int y) {
+      return Integer.divideUnsigned(x, y);
+    }
+  }
+
+  /** Prefer JDK's {@link Long#divideUnsigned(long, long)} over third-party alternatives. */
+  static final class LongDivideUnsigned {
+    @BeforeTemplate
+    long before(long x, long y) {
+      return UnsignedLongs.divide(x, y);
+    }
+
+    @AfterTemplate
+    long after(long x, long y) {
+      return Long.divideUnsigned(x, y);
+    }
+  }
+
+  /** Prefer JDK's {@link Integer#remainderUnsigned(int, int)} over third-party alternatives. */
+  static final class IntegerRemainderUnsigned {
+    @BeforeTemplate
+    int before(int x, int y) {
+      return UnsignedInts.remainder(x, y);
+    }
+
+    @AfterTemplate
+    int after(int x, int y) {
+      return Integer.remainderUnsigned(x, y);
+    }
+  }
+
+  /** Prefer JDK's {@link Long#remainderUnsigned(long, long)} over third-party alternatives. */
+  static final class LongRemainderUnsigned {
+    @BeforeTemplate
+    long before(long x, long y) {
+      return UnsignedLongs.remainder(x, y);
+    }
+
+    @AfterTemplate
+    long after(long x, long y) {
+      return Long.remainderUnsigned(x, y);
+    }
+  }
+
+  /**
+   * Prefer JDK's {@link Integer#parseUnsignedInt(String)} over third-party or more verbose
+   * alternatives.
+   */
+  static final class IntegerParseUnsignedInt {
+    @BeforeTemplate
+    int before(String string) {
+      return Refaster.anyOf(
+          UnsignedInts.parseUnsignedInt(string), Integer.parseUnsignedInt(string, 10));
+    }
+
+    @AfterTemplate
+    int after(String string) {
+      return Integer.parseUnsignedInt(string);
+    }
+  }
+
+  /**
+   * Prefer JDK's {@link Long#parseUnsignedLong(String)} over third-party or more verbose
+   * alternatives.
+   */
+  static final class LongParseUnsignedLong {
+    @BeforeTemplate
+    long before(String string) {
+      return Refaster.anyOf(
+          UnsignedLongs.parseUnsignedLong(string), Long.parseUnsignedLong(string, 10));
+    }
+
+    @AfterTemplate
+    long after(String string) {
+      return Long.parseUnsignedLong(string);
+    }
+  }
+
+  /** Prefer JDK's {@link Integer#parseUnsignedInt(String, int)} over third-party alternatives. */
+  static final class IntegerParseUnsignedIntWithRadix {
+    @BeforeTemplate
+    int before(String string, int radix) {
+      return UnsignedInts.parseUnsignedInt(string, radix);
+    }
+
+    @AfterTemplate
+    int after(String string, int radix) {
+      return Integer.parseUnsignedInt(string, radix);
+    }
+  }
+
+  /** Prefer JDK's {@link Long#parseUnsignedLong(String, int)} over third-party alternatives. */
+  static final class LongParseUnsignedLongWithRadix {
+    @BeforeTemplate
+    long before(String string, int radix) {
+      return UnsignedLongs.parseUnsignedLong(string, radix);
+    }
+
+    @AfterTemplate
+    long after(String string, int radix) {
+      return Long.parseUnsignedLong(string, radix);
+    }
+  }
+
+  /**
+   * Prefer JDK's {@link Integer#toUnsignedString(int)} over third-party or more verbose
+   * alternatives.
+   */
+  static final class IntegerToUnsignedString {
+    @BeforeTemplate
+    String before(int i) {
+      return Refaster.anyOf(UnsignedInts.toString(i), Integer.toUnsignedString(i, 10));
+    }
+
+    @AfterTemplate
+    String after(int i) {
+      return Integer.toUnsignedString(i);
+    }
+  }
+
+  /**
+   * Prefer JDK's {@link Long#toUnsignedString(long)} over third-party or more verbose alternatives.
+   */
+  static final class LongToUnsignedString {
+    @BeforeTemplate
+    String before(long i) {
+      return Refaster.anyOf(UnsignedLongs.toString(i), Long.toUnsignedString(i, 10));
+    }
+
+    @AfterTemplate
+    String after(long i) {
+      return Long.toUnsignedString(i);
+    }
+  }
+
+  /**
+   * Prefer JDK's {@link Integer#toUnsignedString(int,int)} over third-party or more verbose
+   * alternatives.
+   */
+  static final class IntegerToUnsignedStringWithRadix {
+    @BeforeTemplate
+    String before(int i, int radix) {
+      return UnsignedInts.toString(i, radix);
+    }
+
+    @AfterTemplate
+    String after(int i, int radix) {
+      return Integer.toUnsignedString(i, radix);
+    }
+  }
+
+  /**
+   * Prefer JDK's {@link Long#toUnsignedString(long,int)} over third-party or more verbose
+   * alternatives.
+   */
+  static final class LongToUnsignedStringWithRadix {
+    @BeforeTemplate
+    String before(long i, int radix) {
+      return UnsignedLongs.toString(i, radix);
+    }
+
+    @AfterTemplate
+    String after(long i, int radix) {
+      return Long.toUnsignedString(i, radix);
+    }
+  }
 }

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

@@ -3,7 +3,6 @@ package tech.picnic.errorprone.refasterrules;
 import static com.google.common.collect.ImmutableList.toImmutableList;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.MoreCollectors.toOptional;
-import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Comparator.reverseOrder;
@@ -14,6 +13,7 @@ import static java.util.stream.Collectors.toCollection;
 import static org.assertj.core.api.Assertions.assertThat;
 import static reactor.function.TupleUtils.function;
 
+import com.github.benmanes.caffeine.cache.AsyncLoadingCache;
 import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
@@ -34,6 +34,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 import java.util.concurrent.Callable;
+import java.util.concurrent.CompletableFuture;
 import java.util.function.BiConsumer;
 import java.util.function.BiFunction;
 import java.util.function.Consumer;
@@ -41,6 +42,7 @@ import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.function.Supplier;
 import java.util.stream.Collector;
+import java.util.stream.Stream;
 import org.jspecify.annotations.Nullable;
 import org.reactivestreams.Publisher;
 import reactor.core.publisher.Flux;
@@ -52,7 +54,6 @@ import reactor.util.context.Context;
 import reactor.util.function.Tuple2;
 import tech.picnic.errorprone.refaster.annotation.Description;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
-import tech.picnic.errorprone.refaster.annotation.Severity;
 import tech.picnic.errorprone.refaster.matchers.IsEmpty;
 import tech.picnic.errorprone.refaster.matchers.IsIdentityOperation;
 import tech.picnic.errorprone.refaster.matchers.ThrowsCheckedException;
@@ -380,30 +381,23 @@ final class ReactorRules {
   }
 
   /**
-   * Prefer {@link Flux#take(long, boolean)} over {@link Flux#take(long)}.
+   * Prefer {@link Flux#take(long)} over {@link Flux#take(long, boolean)} where relevant.
    *
    * <p>In Reactor versions prior to 3.5.0, {@code Flux#take(long)} makes an unbounded request
-   * upstream, and is equivalent to {@code Flux#take(long, false)}. In 3.5.0, the behavior of {@code
-   * Flux#take(long)} will change to that of {@code Flux#take(long, true)}.
-   *
-   * <p>The intent with this Refaster rule is to get the new behavior before upgrading to Reactor
-   * 3.5.0.
+   * upstream, and is equivalent to {@code Flux#take(long, false)}. From version 3.5.0 onwards, the
+   * behavior of {@code Flux#take(long)} instead matches {@code Flux#take(long, true)}.
    */
-  // XXX: Drop this rule some time after upgrading to Reactor 3.6.0, or introduce a way to apply
-  // this rule only when an older version of Reactor is on the classpath.
-  // XXX: Once Reactor 3.6.0 is out, introduce a rule that rewrites code in the opposite direction.
   @Description(
-      "Prior to Reactor 3.5.0, `take(n)` requests and unbounded number of elements upstream.")
-  @Severity(WARNING)
+      "From Reactor 3.5.0 onwards, `take(n)` no longer requests an unbounded number of elements upstream.")
   static final class FluxTake<T> {
     @BeforeTemplate
     Flux<T> before(Flux<T> flux, long n) {
-      return flux.take(n);
+      return flux.take(n, /* limitRequest= */ true);
     }
 
     @AfterTemplate
     Flux<T> after(Flux<T> flux, long n) {
-      return flux.take(n, /* limitRequest= */ true);
+      return flux.take(n);
     }
   }
 
@@ -489,15 +483,20 @@ final class ReactorRules {
   }
 
   /** Prefer {@link Flux#just(Object)} over more contrived alternatives. */
-  static final class FluxJust {
+  static final class FluxJust<T> {
     @BeforeTemplate
-    Flux<Integer> before(int start) {
-      return Flux.range(start, 1);
+    Flux<Integer> before(int value) {
+      return Flux.range(value, 1);
+    }
+
+    @BeforeTemplate
+    Flux<T> before(T value) {
+      return Mono.just(value).repeat().take(1);
     }
 
     @AfterTemplate
-    Flux<Integer> after(int start) {
-      return Flux.just(start);
+    Flux<T> after(T value) {
+      return Flux.just(value);
     }
   }
 
@@ -566,6 +565,7 @@ final class ReactorRules {
         @Matches(IsIdentityOperation.class)
             Function<? super P, ? extends Publisher<? extends S>> identityOperation) {
       return Refaster.anyOf(
+          flux.concatMap(function, 0),
           flux.flatMap(function, 1),
           flux.flatMapSequential(function, 1),
           flux.map(function).concatMap(identityOperation));
@@ -1205,6 +1205,26 @@ final class ReactorRules {
     }
   }
 
+  /** Prefer {@link Flux#fromIterable(Iterable)} over less efficient alternatives. */
+  // XXX: Once the `FluxFromStreamSupplier` rule is constrained using
+  // `@NotMatches(IsIdentityOperation.class)`, this rule should also cover
+  // `Flux.fromStream(collection.stream())`.
+  static final class FluxFromIterable<T> {
+    // XXX: Once the `MethodReferenceUsage` check is generally enabled, drop the second
+    // `Refaster.anyOf` variant.
+    @BeforeTemplate
+    Flux<T> before(Collection<T> collection) {
+      return Flux.fromStream(
+          Refaster.<Supplier<Stream<? extends T>>>anyOf(
+              collection::stream, () -> collection.stream()));
+    }
+
+    @AfterTemplate
+    Flux<T> after(Collection<T> collection) {
+      return Flux.fromIterable(collection);
+    }
+  }
+
   /**
    * Prefer {@link Flux#count()} followed by a conversion from {@code long} to {@code int} over
    * collecting into a list and counting its elements.
@@ -1722,6 +1742,91 @@ final class ReactorRules {
     }
   }
 
+  /** Prefer {@link PublisherProbe#assertWasSubscribed()} over more verbose alternatives. */
+  static final class PublisherProbeAssertWasSubscribed<T> {
+    @BeforeTemplate
+    void before(PublisherProbe<T> probe) {
+      Refaster.anyOf(
+          assertThat(probe.wasSubscribed()).isTrue(),
+          assertThat(probe.subscribeCount()).isNotNegative(),
+          assertThat(probe.subscribeCount()).isNotEqualTo(0),
+          assertThat(probe.subscribeCount()).isPositive());
+    }
+
+    @AfterTemplate
+    void after(PublisherProbe<T> probe) {
+      probe.assertWasSubscribed();
+    }
+  }
+
+  /** Prefer {@link PublisherProbe#assertWasNotSubscribed()} over more verbose alternatives. */
+  static final class PublisherProbeAssertWasNotSubscribed<T> {
+    @BeforeTemplate
+    void before(PublisherProbe<T> probe) {
+      Refaster.anyOf(
+          assertThat(probe.wasSubscribed()).isFalse(),
+          assertThat(probe.subscribeCount()).isEqualTo(0),
+          assertThat(probe.subscribeCount()).isNotPositive());
+    }
+
+    @AfterTemplate
+    void after(PublisherProbe<T> probe) {
+      probe.assertWasNotSubscribed();
+    }
+  }
+
+  /** Prefer {@link PublisherProbe#assertWasCancelled()} over more verbose alternatives. */
+  static final class PublisherProbeAssertWasCancelled<T> {
+    @BeforeTemplate
+    void before(PublisherProbe<T> probe) {
+      assertThat(probe.wasCancelled()).isTrue();
+    }
+
+    @AfterTemplate
+    void after(PublisherProbe<T> probe) {
+      probe.assertWasCancelled();
+    }
+  }
+
+  /** Prefer {@link PublisherProbe#assertWasNotCancelled()} over more verbose alternatives. */
+  static final class PublisherProbeAssertWasNotCancelled<T> {
+    @BeforeTemplate
+    void before(PublisherProbe<T> probe) {
+      assertThat(probe.wasCancelled()).isFalse();
+    }
+
+    @AfterTemplate
+    void after(PublisherProbe<T> probe) {
+      probe.assertWasNotCancelled();
+    }
+  }
+
+  /** Prefer {@link PublisherProbe#assertWasRequested()} over more verbose alternatives. */
+  static final class PublisherProbeAssertWasRequested<T> {
+    @BeforeTemplate
+    void before(PublisherProbe<T> probe) {
+      assertThat(probe.wasRequested()).isTrue();
+    }
+
+    @AfterTemplate
+    void after(PublisherProbe<T> probe) {
+      probe.assertWasRequested();
+    }
+  }
+
+  /** Prefer {@link PublisherProbe#assertWasNotRequested()} over more verbose alternatives. */
+  static final class PublisherProbeAssertWasNotRequested<T> {
+    @BeforeTemplate
+    void before(PublisherProbe<T> probe) {
+      assertThat(probe.wasRequested()).isFalse();
+    }
+
+    @AfterTemplate
+    void after(PublisherProbe<T> probe) {
+      probe.assertWasNotRequested();
+    }
+  }
+
   /** Prefer {@link Mono#as(Function)} when creating a {@link StepVerifier}. */
   static final class StepVerifierFromMono<T> {
     @BeforeTemplate
@@ -1748,6 +1853,60 @@ final class ReactorRules {
     }
   }
 
+  /**
+   * Prefer {@link StepVerifier#verify()} over a dangling {@link
+   * StepVerifier#verifyThenAssertThat()}.
+   */
+  // XXX: Application of this rule (and several others in this class) will cause invalid code if the
+  // result of the rewritten expression is dereferenced. Consider introducing a bug checker that
+  // identifies rules that change the return type of an expression and annotates them accordingly.
+  // The associated annotation can then be used to instruct an annotation processor to generate
+  // corresponding `void` rules that match only statements. This would allow the `Refaster` check to
+  // conditionally skip "not fully safe" rules. This allows conditionally flagging more dubious
+  // code, at the risk of compilation failures. With this rule, for example, we want to explicitly
+  // nudge users towards `StepVerifier.Step#assertNext(Consumer)` or
+  // `StepVerifier.Step#expectNext(Object)`, together with `Step#verifyComplete()`.
+  static final class StepVerifierVerify {
+    @BeforeTemplate
+    StepVerifier.Assertions before(StepVerifier stepVerifier) {
+      return stepVerifier.verifyThenAssertThat();
+    }
+
+    @AfterTemplate
+    Duration after(StepVerifier stepVerifier) {
+      return stepVerifier.verify();
+    }
+  }
+
+  /**
+   * Prefer {@link StepVerifier#verify(Duration)} over a dangling {@link
+   * StepVerifier#verifyThenAssertThat(Duration)}.
+   */
+  static final class StepVerifierVerifyDuration {
+    @BeforeTemplate
+    StepVerifier.Assertions before(StepVerifier stepVerifier, Duration duration) {
+      return stepVerifier.verifyThenAssertThat(duration);
+    }
+
+    @AfterTemplate
+    Duration after(StepVerifier stepVerifier, Duration duration) {
+      return stepVerifier.verify(duration);
+    }
+  }
+
+  /** Don't unnecessarily invoke {@link StepVerifier#verifyLater()} multiple times. */
+  static final class StepVerifierVerifyLater {
+    @BeforeTemplate
+    StepVerifier before(StepVerifier stepVerifier) {
+      return stepVerifier.verifyLater().verifyLater();
+    }
+
+    @AfterTemplate
+    StepVerifier after(StepVerifier stepVerifier) {
+      return stepVerifier.verifyLater();
+    }
+  }
+
   /** Don't unnecessarily have {@link StepVerifier.Step} expect no elements. */
   static final class StepVerifierStepIdentity<T> {
     @BeforeTemplate
@@ -1848,6 +2007,12 @@ final class ReactorRules {
       return step.expectErrorMatches(predicate).verify();
     }
 
+    @BeforeTemplate
+    @SuppressWarnings("StepVerifierVerify" /* This is a more specific template. */)
+    StepVerifier.Assertions before2(StepVerifier.LastStep step, Predicate<Throwable> predicate) {
+      return step.expectError().verifyThenAssertThat().hasOperatorErrorMatching(predicate);
+    }
+
     @AfterTemplate
     Duration after(StepVerifier.LastStep step, Predicate<Throwable> predicate) {
       return step.verifyErrorMatches(predicate);
@@ -1870,6 +2035,30 @@ final class ReactorRules {
     }
   }
 
+  /**
+   * Prefer {@link StepVerifier.LastStep#verifyErrorSatisfies(Consumer)} with AssertJ over more
+   * contrived alternatives.
+   */
+  static final class StepVerifierLastStepVerifyErrorSatisfiesAssertJ<T extends Throwable> {
+    @BeforeTemplate
+    @SuppressWarnings("StepVerifierVerify" /* This is a more specific template. */)
+    StepVerifier.Assertions before(StepVerifier.LastStep step, Class<T> clazz, String message) {
+      return Refaster.anyOf(
+          step.expectError()
+              .verifyThenAssertThat()
+              .hasOperatorErrorOfType(clazz)
+              .hasOperatorErrorWithMessage(message),
+          step.expectError(clazz).verifyThenAssertThat().hasOperatorErrorWithMessage(message),
+          step.expectErrorMessage(message).verifyThenAssertThat().hasOperatorErrorOfType(clazz));
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    Duration after(StepVerifier.LastStep step, Class<T> clazz, String message) {
+      return step.verifyErrorSatisfies(t -> assertThat(t).isInstanceOf(clazz).hasMessage(message));
+    }
+  }
+
   /**
    * Prefer {@link StepVerifier.LastStep#verifyErrorMessage(String)} over more verbose alternatives.
    */
@@ -1899,4 +2088,76 @@ final class ReactorRules {
       return step.verifyTimeout(duration);
     }
   }
+
+  /**
+   * Prefer {@link Mono#fromFuture(Supplier)} over {@link Mono#fromFuture(CompletableFuture)}, as
+   * the former may defer initiation of the asynchronous computation until subscription.
+   */
+  static final class MonoFromFutureSupplier<T> {
+    // XXX: Constrain the `future` parameter using `@NotMatches(IsIdentityOperation.class)` once
+    // `IsIdentityOperation` no longer matches nullary method invocations.
+    @BeforeTemplate
+    Mono<T> before(CompletableFuture<T> future) {
+      return Mono.fromFuture(future);
+    }
+
+    @AfterTemplate
+    Mono<T> after(CompletableFuture<T> future) {
+      return Mono.fromFuture(() -> future);
+    }
+  }
+
+  /**
+   * Prefer {@link Mono#fromFuture(Supplier, boolean)} over {@link
+   * Mono#fromFuture(CompletableFuture, boolean)}, as the former may defer initiation of the
+   * asynchronous computation until subscription.
+   */
+  static final class MonoFromFutureSupplierBoolean<T> {
+    // XXX: Constrain the `future` parameter using `@NotMatches(IsIdentityOperation.class)` once
+    // `IsIdentityOperation` no longer matches nullary method invocations.
+    @BeforeTemplate
+    Mono<T> before(CompletableFuture<T> future, boolean suppressCancel) {
+      return Mono.fromFuture(future, suppressCancel);
+    }
+
+    @AfterTemplate
+    Mono<T> after(CompletableFuture<T> future, boolean suppressCancel) {
+      return Mono.fromFuture(() -> future, suppressCancel);
+    }
+  }
+
+  /**
+   * Don't propagate {@link Mono} cancellations to an upstream cache value computation, as
+   * completion of such computations may benefit concurrent or subsequent cache usages.
+   */
+  static final class MonoFromFutureAsyncLoadingCacheGet<K, V> {
+    @BeforeTemplate
+    Mono<V> before(AsyncLoadingCache<K, V> cache, K key) {
+      return Mono.fromFuture(() -> cache.get(key));
+    }
+
+    @AfterTemplate
+    Mono<V> after(AsyncLoadingCache<K, V> cache, K key) {
+      return Mono.fromFuture(() -> cache.get(key), /* suppressCancel= */ true);
+    }
+  }
+
+  /**
+   * Prefer {@link Flux#fromStream(Supplier)} over {@link Flux#fromStream(Stream)}, as the former
+   * yields a {@link Flux} that is more likely to behave as expected when subscribed to more than
+   * once.
+   */
+  static final class FluxFromStreamSupplier<T> {
+    // XXX: Constrain the `stream` parameter using `@NotMatches(IsIdentityOperation.class)` once
+    // `IsIdentityOperation` no longer matches nullary method invocations.
+    @BeforeTemplate
+    Flux<T> before(Stream<T> stream) {
+      return Flux.fromStream(stream);
+    }
+
+    @AfterTemplate
+    Flux<T> after(Stream<T> stream) {
+      return Flux.fromStream(() -> stream);
+    }
+  }
 }

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

@@ -4,6 +4,7 @@ import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.naturalOrder;
 import static java.util.Comparator.reverseOrder;
 import static java.util.function.Predicate.not;
+import static java.util.stream.Collectors.collectingAndThen;
 import static java.util.stream.Collectors.counting;
 import static java.util.stream.Collectors.filtering;
 import static java.util.stream.Collectors.flatMapping;
@@ -24,6 +25,7 @@ import com.google.common.collect.Streams;
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.AlsoNegation;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.Matches;
 import com.google.errorprone.refaster.annotation.MayOptionallyUse;
@@ -37,6 +39,7 @@ import java.util.Comparator;
 import java.util.DoubleSummaryStatistics;
 import java.util.IntSummaryStatistics;
 import java.util.LongSummaryStatistics;
+import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.function.BinaryOperator;
@@ -254,32 +257,38 @@ final class StreamRules {
   // XXX: This rule assumes that any matched `Collector` does not perform any filtering.
   // (Perhaps we could add a `@Matches` guard that validates that the collector expression does not
   // contain a `Collectors#filtering` call. That'd still not be 100% accurate, though.)
-  static final class StreamIsEmpty<T> {
+  static final class StreamFindAnyIsEmpty<T, K, V, C extends Collection<K>, M extends Map<K, V>> {
     @BeforeTemplate
-    boolean before(Stream<T> stream, Collector<? super T, ?, ? extends Collection<?>> collector) {
+    boolean before(Stream<T> stream, Collector<? super T, ?, ? extends C> collector) {
       return Refaster.anyOf(
           stream.count() == 0,
           stream.count() <= 0,
           stream.count() < 1,
           stream.findFirst().isEmpty(),
-          stream.collect(collector).isEmpty());
+          stream.collect(collector).isEmpty(),
+          stream.collect(collectingAndThen(collector, C::isEmpty)));
+    }
+
+    @BeforeTemplate
+    boolean before2(Stream<T> stream, Collector<? super T, ?, ? extends M> collector) {
+      return stream.collect(collectingAndThen(collector, M::isEmpty));
     }
 
     @AfterTemplate
+    @AlsoNegation
     boolean after(Stream<T> stream) {
       return stream.findAny().isEmpty();
     }
   }
 
-  /** In order to test whether a stream has any element, simply try to find one. */
-  static final class StreamIsNotEmpty<T> {
+  /**
+   * Prefer {@link Stream#findAny()} over {@link Stream#findFirst()} if one only cares whether the
+   * stream is nonempty.
+   */
+  static final class StreamFindAnyIsPresent<T> {
     @BeforeTemplate
     boolean before(Stream<T> stream) {
-      return Refaster.anyOf(
-          stream.count() != 0,
-          stream.count() > 0,
-          stream.count() >= 1,
-          stream.findFirst().isPresent());
+      return stream.findFirst().isPresent();
     }
 
     @AfterTemplate
@@ -288,6 +297,22 @@ final class StreamRules {
     }
   }
 
+  /**
+   * Prefer an unconditional {@link Map#get(Object)} call followed by a {@code null} check over a
+   * call to {@link Map#containsKey(Object)}, as the former avoids a second lookup operation.
+   */
+  static final class StreamMapFilter<T, K, V> {
+    @BeforeTemplate
+    Stream<V> before(Stream<T> stream, Map<K, V> map) {
+      return stream.filter(map::containsKey).map(map::get);
+    }
+
+    @AfterTemplate
+    Stream<V> after(Stream<T> stream, Map<K, V> map) {
+      return stream.map(map::get).filter(Objects::nonNull);
+    }
+  }
+
   static final class StreamMin<T> {
     @BeforeTemplate
     @SuppressWarnings("java:S4266" /* This violation will be rewritten. */)

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

@@ -9,10 +9,12 @@ import com.google.common.base.Joiner;
 import com.google.common.base.Strings;
 import com.google.common.base.Utf8;
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.FormatMethod;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.AlsoNegation;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.Repeated;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Arrays;
 import java.util.Collection;
@@ -29,9 +31,14 @@ final class StringRules {
   private StringRules() {}
 
   /** Prefer {@link String#isEmpty()} over alternatives that consult the string's length. */
-  // XXX: Once we target JDK 15+, generalize this rule to cover all `CharSequence` subtypes.
+  // XXX: Drop this rule once we (and OpenRewrite) no longer support projects targeting Java 14 or
+  // below. The `CharSequenceIsEmpty` rule then suffices. (This rule exists so that e.g. projects
+  // that target JDK 11 can disable `CharSequenceIsEmpty` without losing a valuable rule.)
+  // XXX: Look into a more general approach to supporting different Java language levels, such as
+  // rule selection based on some annotation, or a separate Maven module.
   static final class StringIsEmpty {
     @BeforeTemplate
+    @SuppressWarnings("CharSequenceIsEmpty" /* This is a more specific template. */)
     boolean before(String str) {
       return Refaster.anyOf(str.length() == 0, str.length() <= 0, str.length() < 1);
     }
@@ -44,7 +51,9 @@ final class StringRules {
   }
 
   /** Prefer a method reference to {@link String#isEmpty()} over the equivalent lambda function. */
-  // XXX: Once we target JDK 15+, generalize this rule to cover all `CharSequence` subtypes.
+  // XXX: Now that we build with JDK 15+, this rule can be generalized to cover all `CharSequence`
+  // subtypes. However, `CharSequence::isEmpty` isn't as nice as `String::isEmpty`, so we might want
+  // to introduce a rule that suggests `String::isEmpty` where possible.
   // XXX: As it stands, this rule is a special case of what `MethodReferenceUsage` tries to achieve.
   // If/when `MethodReferenceUsage` becomes production ready, we should simply drop this check.
   static final class StringIsEmptyPredicate {
@@ -60,7 +69,9 @@ final class StringRules {
   }
 
   /** Prefer a method reference to {@link String#isEmpty()} over the equivalent lambda function. */
-  // XXX: Once we target JDK 15+, generalize this rule to cover all `CharSequence` subtypes.
+  // XXX: Now that we build with JDK 15+, this rule can be generalized to cover all `CharSequence`
+  // subtypes. However, `CharSequence::isEmpty` isn't as nice as `String::isEmpty`, so we might want
+  // to introduce a rule that suggests `String::isEmpty` where possible.
   static final class StringIsNotEmptyPredicate {
     @BeforeTemplate
     Predicate<String> before() {
@@ -162,6 +173,39 @@ final class StringRules {
     }
   }
 
+  /**
+   * Prefer direct invocation of {@link String#String(char[], int, int)} over the indirection
+   * introduced by alternatives.
+   */
+  static final class NewStringFromCharArraySubSequence {
+    @BeforeTemplate
+    String before(char[] data, int offset, int count) {
+      return Refaster.anyOf(
+          String.valueOf(data, offset, count), String.copyValueOf(data, offset, count));
+    }
+
+    @AfterTemplate
+    String after(char[] data, int offset, int count) {
+      return new String(data, offset, count);
+    }
+  }
+
+  /**
+   * Prefer direct invocation of {@link String#String(char[])} over the indirection introduced by
+   * alternatives.
+   */
+  static final class NewStringFromCharArray {
+    @BeforeTemplate
+    String before(char[] data) {
+      return Refaster.anyOf(String.valueOf(data), new String(data, 0, data.length));
+    }
+
+    @AfterTemplate
+    String after(char[] data) {
+      return new String(data);
+    }
+  }
+
   /**
    * Prefer direct delegation to {@link String#valueOf(Object)} over the indirection introduced by
    * {@link Objects#toString(Object)}.
@@ -205,4 +249,124 @@ final class StringRules {
       return Utf8.encodedLength(str);
     }
   }
+
+  /** Prefer {@link String#indexOf(int, int)} over less efficient alternatives. */
+  static final class StringIndexOfChar {
+    @BeforeTemplate
+    @SuppressWarnings("java:S4635" /* This violation will be rewritten. */)
+    int before(String string, int ch, int fromIndex) {
+      return string.substring(fromIndex).indexOf(ch);
+    }
+
+    @AfterTemplate
+    int after(String string, int ch, int fromIndex) {
+      return Math.max(-1, string.indexOf(ch, fromIndex) - fromIndex);
+    }
+  }
+
+  /** Prefer {@link String#indexOf(String, int)} over less efficient alternatives. */
+  static final class StringIndexOfString {
+    @BeforeTemplate
+    @SuppressWarnings("java:S4635" /* This violation will be rewritten. */)
+    int before(String string, String substring, int fromIndex) {
+      return string.substring(fromIndex).indexOf(substring);
+    }
+
+    @AfterTemplate
+    int after(String string, String substring, int fromIndex) {
+      return Math.max(-1, string.indexOf(substring, fromIndex) - fromIndex);
+    }
+  }
+
+  // XXX: Once we compile Refaster templates with JDK 21 also suggest `String#indexOf(int, int,
+  // int)` and `String#indexOf(String, int, int)`.
+
+  /** Prefer {@link String#lastIndexOf(int, int)} over less efficient alternatives. */
+  static final class StringLastIndexOfChar {
+    @BeforeTemplate
+    @SuppressWarnings("java:S4635" /* This violation will be rewritten. */)
+    int before(String string, int ch, int fromIndex) {
+      return string.substring(fromIndex).lastIndexOf(ch);
+    }
+
+    @AfterTemplate
+    int after(String string, int ch, int fromIndex) {
+      return Math.max(-1, string.lastIndexOf(ch) - fromIndex);
+    }
+  }
+
+  /** Prefer {@link String#lastIndexOf(String, int)} over less efficient alternatives. */
+  static final class StringLastIndexOfString {
+    @BeforeTemplate
+    @SuppressWarnings("java:S4635" /* This violation will be rewritten. */)
+    int before(String string, String substring, int fromIndex) {
+      return string.substring(fromIndex).lastIndexOf(substring);
+    }
+
+    @AfterTemplate
+    int after(String string, String substring, int fromIndex) {
+      return Math.max(-1, string.lastIndexOf(substring) - fromIndex);
+    }
+  }
+
+  /** Prefer {@link String#lastIndexOf(int, int)} over less efficient alternatives. */
+  static final class StringLastIndexOfCharWithIndex {
+    @BeforeTemplate
+    int before(String string, int ch, int fromIndex) {
+      return string.substring(0, fromIndex).lastIndexOf(ch);
+    }
+
+    @AfterTemplate
+    int after(String string, int ch, int fromIndex) {
+      return string.lastIndexOf(ch, fromIndex - 1);
+    }
+  }
+
+  /** Prefer {@link String#lastIndexOf(String, int)} over less efficient alternatives. */
+  // XXX: The replacement expression isn't fully equivalent: in case `substring` is empty, then
+  // the replacement yields `fromIndex - 1` rather than `fromIndex`.
+  static final class StringLastIndexOfStringWithIndex {
+    @BeforeTemplate
+    int before(String string, String substring, int fromIndex) {
+      return string.substring(0, fromIndex).lastIndexOf(substring);
+    }
+
+    @AfterTemplate
+    int after(String string, String substring, int fromIndex) {
+      return string.lastIndexOf(substring, fromIndex - 1);
+    }
+  }
+
+  /** Prefer {@link String#startsWith(String, int)} over less efficient alternatives. */
+  static final class StringStartsWith {
+    @BeforeTemplate
+    @SuppressWarnings("java:S4635" /* This violation will be rewritten. */)
+    boolean before(String string, String prefix, int fromIndex) {
+      return string.substring(fromIndex).startsWith(prefix);
+    }
+
+    @AfterTemplate
+    boolean after(String string, String prefix, int fromIndex) {
+      return string.startsWith(prefix, fromIndex);
+    }
+  }
+
+  /**
+   * Prefer {@link String#formatted(Object...)} over {@link String#format(String, Object...)}, as
+   * the former works more nicely with text blocks, while the latter does not appear advantageous in
+   * any circumstance (assuming one targets JDK 15+).
+   */
+  static final class StringFormatted {
+    @BeforeTemplate
+    @FormatMethod
+    String before(String format, @Repeated Object args) {
+      return String.format(format, args);
+    }
+
+    @AfterTemplate
+    @FormatMethod
+    String after(String format, @Repeated Object args) {
+      return format.formatted(args);
+    }
+  }
 }

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

@@ -29,6 +29,7 @@ import org.assertj.core.api.ThrowableAssert.ThrowingCallable;
 import org.testng.Assert;
 import org.testng.Assert.ThrowingRunnable;
 import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
+import tech.picnic.errorprone.refaster.annotation.TypeMigration;
 
 /**
  * Refaster rules that replace TestNG assertions with equivalent AssertJ assertions.
@@ -48,32 +49,107 @@ import tech.picnic.errorprone.refaster.annotation.OnlineDocumentation;
  * List<Map<String, Object>> myMaps = new ArrayList<>();
  * assertEquals(myMaps, ImmutableList.of(ImmutableMap.of()));
  * }</pre>
- *
- * <p>A few {@link Assert} methods are not rewritten:
- *
- * <ul>
- *   <li>These methods cannot (easily) be expressed using AssertJ because they mix regular equality
- *       and array equality:
- *       <ul>
- *         <li>{@link Assert#assertEqualsDeep(Map, Map)}
- *         <li>{@link Assert#assertEqualsDeep(Map, Map, String)}
- *         <li>{@link Assert#assertEqualsDeep(Set, Set, String)}
- *         <li>{@link Assert#assertNotEqualsDeep(Map, Map)}
- *         <li>{@link Assert#assertNotEqualsDeep(Map, Map, String)}
- *         <li>{@link Assert#assertNotEqualsDeep(Set, Set)}
- *         <li>{@link Assert#assertNotEqualsDeep(Set, Set, String)}
- *       </ul>
- *   <li>This method returns the caught exception; there is no direct counterpart for this in
- *       AssertJ:
- *       <ul>
- *         <li>{@link Assert#expectThrows(Class, ThrowingRunnable)}
- *       </ul>
- * </ul>
  */
 // XXX: As-is these rules do not result in a complete migration:
 // - Expressions containing comments are skipped due to a limitation of Refaster.
 // - Assertions inside lambda expressions are also skipped. Unclear why.
+// XXX: The `assertEquals` tests for this class generally use the same expression for `expected` and
+// `actual`, which makes the validation weaker than necessary; fix this. (And investigate whether we
+// can introduce validation for this.)
 @OnlineDocumentation
+@TypeMigration(
+    of = Assert.class,
+    unmigratedMethods = {
+      // XXX: Add migrations for the methods below.
+      "assertEquals(Boolean, Boolean)",
+      "assertEquals(Boolean, boolean)",
+      "assertEquals(boolean, Boolean)",
+      "assertEquals(Boolean, Boolean, String)",
+      "assertEquals(Boolean, boolean, String)",
+      "assertEquals(boolean, Boolean, String)",
+      "assertEquals(Byte, Byte)",
+      "assertEquals(Byte, byte)",
+      "assertEquals(byte, Byte)",
+      "assertEquals(Byte, Byte, String)",
+      "assertEquals(Byte, byte, String)",
+      "assertEquals(byte, Byte, String)",
+      "assertEquals(char, Character)",
+      "assertEquals(char, Character, String)",
+      "assertEquals(Character, char)",
+      "assertEquals(Character, char, String)",
+      "assertEquals(Character, Character)",
+      "assertEquals(Character, Character, String)",
+      "assertEquals(Double, Double)",
+      "assertEquals(Double, double)",
+      "assertEquals(double, Double)",
+      "assertEquals(Double, Double, String)",
+      "assertEquals(Double, double, String)",
+      "assertEquals(double, Double, String)",
+      "assertEquals(double[], double[], double)",
+      "assertEquals(double[], double[], double, String)",
+      "assertEquals(Float, Float)",
+      "assertEquals(Float, float)",
+      "assertEquals(float, Float)",
+      "assertEquals(Float, Float, String)",
+      "assertEquals(Float, float, String)",
+      "assertEquals(float, Float, String)",
+      "assertEquals(float[], float[], float)",
+      "assertEquals(float[], float[], float, String)",
+      "assertEquals(int, Integer)",
+      "assertEquals(int, Integer, String)",
+      "assertEquals(Integer, int)",
+      "assertEquals(Integer, int, String)",
+      "assertEquals(Integer, Integer)",
+      "assertEquals(Integer, Integer, String)",
+      "assertEquals(Long, Long)",
+      "assertEquals(Long, long)",
+      "assertEquals(long, Long)",
+      "assertEquals(Long, Long, String)",
+      "assertEquals(Long, long, String)",
+      "assertEquals(Short, Short)",
+      "assertEquals(Short, short)",
+      "assertEquals(short, Short)",
+      "assertEquals(Short, Short, String)",
+      "assertEquals(Short, short, String)",
+      "assertEquals(short, Short, String)",
+      /*
+       * These `assertEqualsDeep` methods cannot (easily) be expressed using AssertJ because they
+       * mix regular equality and array equality:
+       */
+      "assertEqualsDeep(Map<?, ?>, Map<?, ?>)",
+      "assertEqualsDeep(Map<?, ?>, Map<?, ?>, String)",
+      "assertEqualsDeep(Set<?>, Set<?>, String)",
+      // XXX: Add migrations for the methods below.
+      "assertEqualsNoOrder(Collection<?>, Collection<?>)",
+      "assertEqualsNoOrder(Collection<?>, Collection<?>, String)",
+      "assertEqualsNoOrder(Iterator<?>, Iterator<?>)",
+      "assertEqualsNoOrder(Iterator<?>, Iterator<?>, String)",
+      "assertListContains(List<T>, Predicate<T>, String)",
+      "assertListContainsObject(List<T>, T, String)",
+      "assertListNotContains(List<T>, Predicate<T>, String)",
+      "assertListNotContainsObject(List<T>, T, String)",
+      "assertNotEquals(Collection<?>, Collection<?>)",
+      "assertNotEquals(Collection<?>, Collection<?>, String)",
+      "assertNotEquals(Iterator<?>, Iterator<?>)",
+      "assertNotEquals(Iterator<?>, Iterator<?>, String)",
+      "assertNotEquals(Object[], Object[], String)",
+      /*
+       * These `assertNotEqualsDeep` methods cannot (easily) be expressed using AssertJ because they
+       * mix regular equality and array equality:
+       */
+      "assertNotEqualsDeep(Map<?, ?>, Map<?, ?>)",
+      "assertNotEqualsDeep(Map<?, ?>, Map<?, ?>, String)",
+      "assertNotEqualsDeep(Set<?>, Set<?>)",
+      "assertNotEqualsDeep(Set<?>, Set<?>, String)",
+      // XXX: Add a migration for this `assertThrows` method.
+      "assertThrows(String, Class<T>, ThrowingRunnable)",
+      /*
+       * These `expectThrows` methods return the caught exception; there is no direct counterpart
+       * for this in AssertJ.
+       */
+      "expectThrows(Class<T>, ThrowingRunnable)",
+      "expectThrows(String, Class<T>, ThrowingRunnable)"
+    })
 final class TestNGToAssertJRules {
   private TestNGToAssertJRules() {}
 
@@ -85,8 +161,9 @@ final class TestNGToAssertJRules {
 
     @AfterTemplate
     @DoNotCall
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     void after() {
-      throw new AssertionError();
+      fail();
     }
   }
 

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

@@ -142,6 +142,63 @@ final class TimeRules {
     }
   }
 
+  /** Don't unnecessarily transform an {@link Instant} to an equivalent instance. */
+  static final class InstantIdentity {
+    @BeforeTemplate
+    Instant before(Instant instant, TemporalUnit temporalUnit) {
+      return Refaster.anyOf(
+          instant.plus(Duration.ZERO),
+          instant.plus(0, temporalUnit),
+          instant.plusNanos(0),
+          instant.plusMillis(0),
+          instant.plusSeconds(0),
+          instant.minus(Duration.ZERO),
+          instant.minus(0, temporalUnit),
+          instant.minusNanos(0),
+          instant.minusMillis(0),
+          instant.minusSeconds(0),
+          Instant.parse(instant.toString()),
+          instant.truncatedTo(ChronoUnit.NANOS),
+          Instant.ofEpochSecond(instant.getEpochSecond(), instant.getNano()));
+    }
+
+    @AfterTemplate
+    Instant after(Instant instant) {
+      return instant;
+    }
+  }
+
+  /**
+   * Prefer {@link Instant#truncatedTo(TemporalUnit)} over less obvious alternatives.
+   *
+   * <p>Note that {@link Instant#toEpochMilli()} throws an {@link ArithmeticException} for dates
+   * very far in the past or future, while the suggested alternative doesn't.
+   */
+  static final class InstantTruncatedToMilliseconds {
+    @BeforeTemplate
+    Instant before(Instant instant) {
+      return Instant.ofEpochMilli(instant.toEpochMilli());
+    }
+
+    @AfterTemplate
+    Instant after(Instant instant) {
+      return instant.truncatedTo(ChronoUnit.MILLIS);
+    }
+  }
+
+  /** Prefer {@link Instant#truncatedTo(TemporalUnit)} over less obvious alternatives. */
+  static final class InstantTruncatedToSeconds {
+    @BeforeTemplate
+    Instant before(Instant instant) {
+      return Instant.ofEpochSecond(instant.getEpochSecond());
+    }
+
+    @AfterTemplate
+    Instant after(Instant instant) {
+      return instant.truncatedTo(ChronoUnit.SECONDS);
+    }
+  }
+
   /** Prefer {@link Instant#atOffset(ZoneOffset)} over more verbose alternatives. */
   static final class InstantAtOffset {
     @BeforeTemplate

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

@@ -0,0 +1,71 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class ClassCastLambdaUsageTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(ClassCastLambdaUsage.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import com.google.common.collect.ImmutableSet;",
+            "import java.util.stream.IntStream;",
+            "import java.util.stream.Stream;",
+            "",
+            "class A {",
+            "  <T> void m() {",
+            "    Number localVariable = 0;",
+            "",
+            "    Stream.of(0).map(i -> i);",
+            "    Stream.of(1).map(i -> i + 1);",
+            "    Stream.of(2).map(Integer.class::cast);",
+            "    Stream.of(3).map(i -> (Integer) 2);",
+            "    Stream.of(4).map(i -> (Integer) localVariable);",
+            "    // XXX: Ideally this case is also flagged. Pick this up in the context of merging the",
+            "    // `ClassCastLambdaUsage` and `MethodReferenceUsage` checks, or introduce a separate check that",
+            "    // simplifies unnecessary block lambda expressions.",
+            "    Stream.of(5)",
+            "        .map(",
+            "            i -> {",
+            "              return (Integer) i;",
+            "            });",
+            "    Stream.<ImmutableSet>of(ImmutableSet.of(6)).map(s -> (ImmutableSet<Number>) s);",
+            "    Stream.of(ImmutableSet.of(7)).map(s -> (ImmutableSet<?>) s);",
+            "    Stream.of(8).reduce((a, b) -> (Integer) a);",
+            "    IntStream.of(9).mapToObj(i -> (char) i);",
+            "    Stream.of(10).map(i -> (T) i);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Stream.of(11).map(i -> (Integer) i);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(ClassCastLambdaUsage.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import java.util.stream.Stream;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Stream.of(1).map(i -> (Integer) i);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import java.util.stream.Stream;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Stream.of(1).map(Integer.class::cast);",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -0,0 +1,78 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class ConstantNamingTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(ConstantNaming.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "class A {",
+            "  private static final long serialVersionUID = 1L;",
+            "  private static final int FOO = 1;",
+            "  // BUG: Diagnostic contains: consider renaming to 'BAR', though note that this is not a private",
+            "  // constant",
+            "  static final int bar = 2;",
+            "  // BUG: Diagnostic contains:",
+            "  private static final int baz = 3;",
+            "  // BUG: Diagnostic contains: consider renaming to 'QUX_QUUX', though note that a variable with",
+            "  // this name is already declared",
+            "  private static final int qux_QUUX = 4;",
+            "  // BUG: Diagnostic contains: consider renaming to 'QUUZ', though note that a variable with",
+            "  // this name is already declared",
+            "  private static final int quuz = 3;",
+            "",
+            "  private final int foo = 4;",
+            "  private final Runnable QUX_QUUX =",
+            "      new Runnable() {",
+            "        private static final int QUUZ = 1;",
+            "",
+            "        @Override",
+            "        public void run() {}",
+            "      };",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void identificationWithCustomExemption() {
+    CompilationTestHelper.newInstance(ConstantNaming.class, getClass())
+        .setArgs("-XepOpt:CanonicalConstantNaming:ExemptedNames=foo,baz")
+        .addSourceLines(
+            "A.java",
+            "class A {",
+            "  private static final long serialVersionUID = 1L;",
+            "  private static final int foo = 1;",
+            "  // BUG: Diagnostic contains:",
+            "  private static final int bar = 2;",
+            "  private static final int baz = 3;",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(ConstantNaming.class, getClass())
+        .addInputLines(
+            "A.java",
+            "class A {",
+            "  static final int foo = 1;",
+            "  private static final int bar = 2;",
+            "  private static final int baz = 3;",
+            "  private static final int BAZ = 4;",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "class A {",
+            "  static final int foo = 1;",
+            "  private static final int BAR = 2;",
+            "  private static final int baz = 3;",
+            "  private static final int BAZ = 4;",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -0,0 +1,80 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class EmptyMonoZipTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(EmptyMonoZip.class, getClass())
+        .expectErrorMessage(
+            "ARGUMENT",
+            m ->
+                m.contains(
+                    "Don't pass a `Mono<Void>` or `Mono.empty()` argument to `Mono#{zip,With}`"))
+        .expectErrorMessage(
+            "RECEIVER",
+            m ->
+                m.contains(
+                    "Invoking `Mono#zipWith` on `Mono#empty()` or a `Mono<Void>` is a no-op"))
+        .addSourceLines(
+            "A.java",
+            "import static reactor.core.publisher.Mono.zip;",
+            "",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.core.publisher.Mono;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).zip(Mono.empty(), Flux.just(2));",
+            "",
+            "    Mono<Void> voidMono = Mono.empty();",
+            "    Mono<Integer> integerMono = Mono.empty();",
+            "",
+            "    zip(Mono.just(1), Mono.just(2));",
+            "    Mono.zip(Mono.just(1), Mono.just(2));",
+            "    Mono.zip(Mono.just(1), Mono.just(2), Mono.just(3));",
+            "    Mono.zip(integerMono, integerMono);",
+            "",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    zip(Mono.empty(), Mono.empty());",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    Mono.zip(Mono.empty(), Mono.empty());",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    Mono.zip(voidMono, Mono.just(1));",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    Mono.zip(voidMono, voidMono);",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    Mono.zip(Mono.just(1).then(), Mono.just(2));",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    Mono.zip(Mono.just(1), Mono.just(2), voidMono);",
+            "",
+            "    Mono.just(1).zipWith(Mono.just(2));",
+            "    Mono.just(1).zipWith(integerMono);",
+            "    Mono.just(1).zipWith(integerMono, (a, b) -> a + b);",
+            "",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    Mono.just(1).zipWith(Mono.empty());",
+            "    // BUG: Diagnostic matches: ARGUMENT",
+            "    Mono.just(1).zipWith(voidMono);",
+            "    // BUG: Diagnostic matches: RECEIVER",
+            "    Mono.empty().zipWith(Mono.just(1));",
+            "    // BUG: Diagnostic matches: RECEIVER",
+            "    voidMono.zipWith(Mono.just(1));",
+            "  }",
+            "",
+            "  abstract class MyMono extends Mono<Object> {",
+            "    void m() {",
+            "      zip(Mono.just(1), Mono.just(2));",
+            "      // BUG: Diagnostic matches: ARGUMENT",
+            "      zip(Mono.empty(), Mono.empty());",
+            "",
+            "      zipWith(Mono.just(1));",
+            "      // BUG: Diagnostic matches: ARGUMENT",
+            "      zipWith(Mono.empty());",
+            "    }",
+            "  }",
+            "}")
+        .doTest();
+  }
+}

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

@@ -0,0 +1,175 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class ExplicitArgumentEnumerationTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(ExplicitArgumentEnumeration.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import com.google.errorprone.bugpatterns.BugChecker;",
+            "import org.jooq.impl.DSL;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.test.StepVerifier;",
+            "",
+            "class A {",
+            "  // BUG: Diagnostic contains:",
+            "  private final int value = unaryMethod(ImmutableList.of(1, 2));",
+            "",
+            "  void m() {",
+            "    ImmutableList<String> list = ImmutableList.of();",
+            "    assertThat(ImmutableList.of()).containsAnyElementsOf(list);",
+            "",
+            "    ImmutableList.<ImmutableList<String>>builder().add(ImmutableList.of());",
+            "",
+            "    DSL.row(ImmutableList.of(1, 2));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    unaryMethod(ImmutableList.of(1, 2));",
+            "    unaryMethodWithLessVisibleOverload(ImmutableList.of(1, 2));",
+            "    binaryMethod(ImmutableList.of(1, 2), 3);",
+            "",
+            "    ImmutableList.builder()",
+            "        // BUG: Diagnostic contains:",
+            "        .addAll(ImmutableList.of())",
+            "        // BUG: Diagnostic contains:",
+            "        .addAll(ImmutableList.copyOf(new String[0]))",
+            "        .addAll(ImmutableList.copyOf(ImmutableList.of()))",
+            "        .build();",
+            "",
+            "    assertThat(ImmutableList.of(1))",
+            "        // BUG: Diagnostic contains:",
+            "        .containsAnyElementsOf(ImmutableList.of(1))",
+            "        // BUG: Diagnostic contains:",
+            "        .isSubsetOf(ImmutableList.of(1));",
+            "",
+            "    Flux.just(1, 2)",
+            "        .as(StepVerifier::create)",
+            "        // BUG: Diagnostic contains:",
+            "        .expectNextSequence(ImmutableList.of(1, 2))",
+            "        .verifyComplete();",
+            "",
+            "    CompilationTestHelper.newInstance(BugChecker.class, getClass())",
+            "        // BUG: Diagnostic contains:",
+            "        .setArgs(ImmutableList.of(\"foo\"))",
+            "        .withClasspath();",
+            "  }",
+            "",
+            "  private int unaryMethod(ImmutableList<Integer> args) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  private int unaryMethod(Integer... args) {",
+            "    return unaryMethod(ImmutableList.copyOf(args));",
+            "  }",
+            "",
+            "  void unaryMethodWithLessVisibleOverload(ImmutableList<Integer> args) {}",
+            "",
+            "  private void unaryMethodWithLessVisibleOverload(Integer... args) {",
+            "    unaryMethodWithLessVisibleOverload(ImmutableList.copyOf(args));",
+            "  }",
+            "",
+            "  private void binaryMethod(ImmutableList<Integer> args, int extraArg) {}",
+            "",
+            "  private void binaryMethod(Integer... args) {",
+            "    binaryMethod(ImmutableList.copyOf(args), 0);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(ExplicitArgumentEnumeration.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.ImmutableMultiset;",
+            "import com.google.common.collect.ImmutableSet;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import com.google.errorprone.bugpatterns.BugChecker;",
+            "import java.util.Arrays;",
+            "import java.util.List;",
+            "import java.util.Set;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.test.StepVerifier;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    ImmutableList.builder().addAll(ImmutableList.of()).build();",
+            "",
+            "    assertThat(ImmutableList.of()).containsAnyElementsOf(ImmutableMultiset.of());",
+            "    assertThat(ImmutableList.of()).containsAll(ImmutableSet.of());",
+            "    assertThat(ImmutableList.of()).containsExactlyElementsOf(List.of());",
+            "    assertThat(ImmutableList.of()).containsExactlyInAnyOrderElementsOf(Set.of());",
+            "    assertThat(ImmutableList.of()).containsSequence(Arrays.asList());",
+            "    assertThat(ImmutableList.of()).containsSubsequence(ImmutableList.of(1));",
+            "    assertThat(ImmutableList.of()).doesNotContainAnyElementsOf(ImmutableMultiset.of(2));",
+            "    assertThat(ImmutableList.of()).doesNotContainSequence(ImmutableSet.of(3));",
+            "    assertThat(ImmutableList.of()).doesNotContainSubsequence(List.of(4));",
+            "    assertThat(ImmutableList.of()).hasSameElementsAs(Set.of(5));",
+            "    assertThat(ImmutableList.of()).isSubsetOf(Arrays.asList(6));",
+            "",
+            "    Flux.empty()",
+            "        .as(StepVerifier::create)",
+            "        .expectNextSequence(ImmutableList.of(1, 2))",
+            "        .verifyComplete();",
+            "",
+            "    BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass())",
+            "        .setArgs(ImmutableList.of(\"foo\", \"bar\"));",
+            "    CompilationTestHelper.newInstance(BugChecker.class, getClass())",
+            "        .setArgs(ImmutableList.of(\"foo\", \"bar\"));",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.ImmutableMultiset;",
+            "import com.google.common.collect.ImmutableSet;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import com.google.errorprone.bugpatterns.BugChecker;",
+            "import java.util.Arrays;",
+            "import java.util.List;",
+            "import java.util.Set;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.test.StepVerifier;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    ImmutableList.builder().add().build();",
+            "",
+            "    assertThat(ImmutableList.of()).containsAnyOf();",
+            "    assertThat(ImmutableList.of()).contains();",
+            "    assertThat(ImmutableList.of()).containsExactly();",
+            "    assertThat(ImmutableList.of()).containsExactlyInAnyOrder();",
+            "    assertThat(ImmutableList.of()).containsSequence();",
+            "    assertThat(ImmutableList.of()).containsSubsequence(1);",
+            "    assertThat(ImmutableList.of()).doesNotContain(2);",
+            "    assertThat(ImmutableList.of()).doesNotContainSequence(3);",
+            "    assertThat(ImmutableList.of()).doesNotContainSubsequence(4);",
+            "    assertThat(ImmutableList.of()).containsOnly(5);",
+            "    assertThat(ImmutableList.of()).isSubsetOf(6);",
+            "",
+            "    Flux.empty().as(StepVerifier::create).expectNext(1, 2).verifyComplete();",
+            "",
+            "    BugCheckerRefactoringTestHelper.newInstance(BugChecker.class, getClass()).setArgs(\"foo\", \"bar\");",
+            "    CompilationTestHelper.newInstance(BugChecker.class, getClass()).setArgs(\"foo\", \"bar\");",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -28,6 +28,8 @@ final class IdentityConversionTest {
             "import com.google.common.collect.ImmutableTable;",
             "import com.google.errorprone.matchers.Matcher;",
             "import com.google.errorprone.matchers.Matchers;",
+            "import java.time.Instant;",
+            "import java.time.ZonedDateTime;",
             "import reactor.adapter.rxjava.RxJava2Adapter;",
             "import reactor.core.publisher.Flux;",
             "import reactor.core.publisher.Mono;",
@@ -149,6 +151,10 @@ final class IdentityConversionTest {
             "    // BUG: Diagnostic contains:",
             "    ImmutableTable<Object, Object, Object> o11 = ImmutableTable.copyOf(ImmutableTable.of());",
             "",
+            "    Instant instant1 = Instant.from(ZonedDateTime.now());",
+            "    // BUG: Diagnostic contains:",
+            "    Instant instant2 = Instant.from(Instant.now());",
+            "",
             "    // BUG: Diagnostic contains:",
             "    Matcher allOf1 = Matchers.allOf(instanceMethod());",
             "    Matcher allOf2 = Matchers.allOf(instanceMethod(), staticMethod());",

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

@@ -18,22 +18,23 @@ final class IsInstanceLambdaUsageTest {
             "  void m() {",
             "    Integer localVariable = 0;",
             "",
-            "    Stream.of(0).map(i -> i + 1);",
-            "    Stream.of(1).filter(Integer.class::isInstance);",
-            "    Stream.of(2).filter(i -> i.getClass() instanceof Class);",
-            "    Stream.of(3).filter(i -> localVariable instanceof Integer);",
+            "    Stream.of(0).map(i -> i);",
+            "    Stream.of(1).map(i -> i + 1);",
+            "    Stream.of(2).filter(Integer.class::isInstance);",
+            "    Stream.of(3).filter(i -> i.getClass() instanceof Class);",
+            "    Stream.of(4).filter(i -> localVariable instanceof Integer);",
             "    // XXX: Ideally this case is also flagged. Pick this up in the context of merging the",
             "    // `IsInstanceLambdaUsage` and `MethodReferenceUsage` checks, or introduce a separate check that",
             "    // simplifies unnecessary block lambda expressions.",
-            "    Stream.of(4)",
+            "    Stream.of(5)",
             "        .filter(",
             "            i -> {",
-            "              return localVariable instanceof Integer;",
+            "              return i instanceof Integer;",
             "            });",
-            "    Flux.just(5, \"foo\").distinctUntilChanged(v -> v, (a, b) -> a instanceof Integer);",
+            "    Flux.just(6, \"foo\").distinctUntilChanged(v -> v, (a, b) -> a instanceof Integer);",
             "",
             "    // BUG: Diagnostic contains:",
-            "    Stream.of(6).filter(i -> i instanceof Integer);",
+            "    Stream.of(7).filter(i -> i instanceof Integer);",
             "  }",
             "}")
         .doTest();

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

@@ -11,7 +11,7 @@ final class JUnitMethodDeclarationTest {
     CompilationTestHelper.newInstance(JUnitMethodDeclaration.class, getClass())
         .addSourceLines(
             "A.java",
-            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
+            "import static org.junit.jupiter.params.provider.Arguments.*;",
             "",
             "import org.junit.jupiter.api.AfterAll;",
             "import org.junit.jupiter.api.AfterEach;",
@@ -154,8 +154,10 @@ final class JUnitMethodDeclarationTest {
             "  void overload() {}",
             "",
             "  @Test",
-            "  // BUG: Diagnostic contains: (but note that `arguments` is already statically imported)",
-            "  void testArguments() {}",
+            "  // BUG: Diagnostic contains: (but note that another method named `arguments` is in scope)",
+            "  void testArguments() {",
+            "    arguments();",
+            "  }",
             "",
             "  @Test",
             "  // BUG: Diagnostic contains: (but note that `public` is not a valid identifier)",

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

@@ -1,6 +1,5 @@
 package tech.picnic.errorprone.bugpatterns;
 
-import com.google.common.collect.ImmutableList;
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
@@ -29,6 +28,10 @@ final class LexicographicalAnnotationAttributeListingTest {
             "  @interface Foo {",
             "    String[] value() default {};",
             "",
+            "    boolean[] bools() default {};",
+            "",
+            "    char[] chars() default {};",
+            "",
             "    int[] ints() default {};",
             "",
             "    Class<?>[] cls() default {};",
@@ -69,6 +72,32 @@ final class LexicographicalAnnotationAttributeListingTest {
             "  @Foo({\"a\", \"A\"})",
             "  A unsortedStringCaseInsensitiveWithTotalOrderFallback();",
             "",
+            "  @Foo(bools = {})",
+            "  A noBools();",
+            "",
+            "  @Foo(bools = {false})",
+            "  A oneBool();",
+            "",
+            "  @Foo(bools = {false, true})",
+            "  A sortedBools();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(bools = {true, false})",
+            "  A unsortedBools();",
+            "",
+            "  @Foo(chars = {})",
+            "  A noChars();",
+            "",
+            "  @Foo(chars = {'a'})",
+            "  A oneChar();",
+            "",
+            "  @Foo(chars = {'a', 'b'})",
+            "  A sortedChars();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(chars = {'b', 'a'})",
+            "  A unsortedChars();",
+            "",
             "  @Foo(ints = {})",
             "  A noInts();",
             "",
@@ -173,6 +202,10 @@ final class LexicographicalAnnotationAttributeListingTest {
             "  @interface Foo {",
             "    String[] value() default {};",
             "",
+            "    boolean[] bools() default {};",
+            "",
+            "    char[] chars() default {};",
+            "",
             "    Class<?>[] cls() default {};",
             "",
             "    RoundingMode[] enums() default {};",
@@ -185,7 +218,13 @@ final class LexicographicalAnnotationAttributeListingTest {
             "  }",
             "",
             "  @Foo({\" \", \"\", \"b\", \"a\"})",
-            "  A unsortedString();",
+            "  A unsortedStrings();",
+            "",
+            "  @Foo(bools = {true, false})",
+            "  A unsortedBooleans();",
+            "",
+            "  @Foo(chars = {'b', 'a'})",
+            "  A unsortedChars();",
             "",
             "  @Foo(cls = {long.class, int.class})",
             "  A unsortedClasses();",
@@ -210,6 +249,10 @@ final class LexicographicalAnnotationAttributeListingTest {
             "  @interface Foo {",
             "    String[] value() default {};",
             "",
+            "    boolean[] bools() default {};",
+            "",
+            "    char[] chars() default {};",
+            "",
             "    Class<?>[] cls() default {};",
             "",
             "    RoundingMode[] enums() default {};",
@@ -222,7 +265,13 @@ final class LexicographicalAnnotationAttributeListingTest {
             "  }",
             "",
             "  @Foo({\"\", \" \", \"a\", \"b\"})",
-            "  A unsortedString();",
+            "  A unsortedStrings();",
+            "",
+            "  @Foo(bools = {false, true})",
+            "  A unsortedBooleans();",
+            "",
+            "  @Foo(chars = {'a', 'b'})",
+            "  A unsortedChars();",
             "",
             "  @Foo(cls = {int.class, long.class})",
             "  A unsortedClasses();",
@@ -244,9 +293,8 @@ final class LexicographicalAnnotationAttributeListingTest {
     /* Some violations are not flagged because they are not in- or excluded. */
     CompilationTestHelper.newInstance(LexicographicalAnnotationAttributeListing.class, getClass())
         .setArgs(
-            ImmutableList.of(
-                "-XepOpt:LexicographicalAnnotationAttributeListing:Includes=pkg.A.Foo,pkg.A.Bar",
-                "-XepOpt:LexicographicalAnnotationAttributeListing:Excludes=pkg.A.Bar#value"))
+            "-XepOpt:LexicographicalAnnotationAttributeListing:Includes=pkg.A.Foo,pkg.A.Bar",
+            "-XepOpt:LexicographicalAnnotationAttributeListing:Excludes=pkg.A.Bar#value")
         .addSourceLines(
             "pkg/A.java",
             "package pkg;",

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

@@ -0,0 +1,137 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class OptionalOrElseGetTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(OptionalOrElseGet.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import com.google.errorprone.refaster.Refaster;",
+            "import java.util.Optional;",
+            "import java.util.function.Supplier;",
+            "",
+            "class A {",
+            "  private final Optional<Object> optional = Optional.empty();",
+            "  private final String string = optional.toString();",
+            "",
+            "  void m() {",
+            "    Optional.empty().orElse(null);",
+            "    optional.orElse(null);",
+            "    optional.orElse(\"constant\");",
+            "    optional.orElse(\"constant\" + 0);",
+            "    optional.orElse(Boolean.TRUE);",
+            "    optional.orElse(string);",
+            "    optional.orElse(this.string);",
+            "    optional.orElse(Refaster.anyOf(\"constant\", \"another\"));",
+            "    Optional.<Supplier<String>>empty().orElse(() -> \"constant\");",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Optional.empty().orElse(string + \"constant\");",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(string + \"constant\");",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(\"constant\".toString());",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(string.toString());",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(this.string.toString());",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(String.valueOf(42));",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(string.toString().length());",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(\"constant\".equals(string));",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(string.equals(string));",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(this.string.equals(string));",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(foo());",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(this.foo());",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(new Object() {});",
+            "    // BUG: Diagnostic contains:",
+            "    optional.orElse(new int[0].length);",
+            "  }",
+            "",
+            "  private <T> T foo() {",
+            "    return null;",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(OptionalOrElseGet.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import java.util.Optional;",
+            "",
+            "class A {",
+            "  private final Optional<Object> optional = Optional.empty();",
+            "  private final String string = optional.toString();",
+            "",
+            "  void m() {",
+            "    optional.orElse(string + \"constant\");",
+            "    optional.orElse(\"constant\".toString());",
+            "    optional.orElse(string.toString());",
+            "    optional.orElse(this.string.toString());",
+            "    optional.orElse(String.valueOf(42));",
+            "    optional.orElse(string.toString().length());",
+            "    optional.orElse(string.equals(string));",
+            "    optional.orElse(foo());",
+            "    optional.orElse(this.<Number>foo());",
+            "    optional.orElse(this.<String, Integer>bar());",
+            "    optional.orElse(new Object() {});",
+            "    optional.orElse(new int[0].length);",
+            "  }",
+            "",
+            "  private <T> T foo() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private <S, T> T bar() {",
+            "    return null;",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import java.util.Optional;",
+            "",
+            "class A {",
+            "  private final Optional<Object> optional = Optional.empty();",
+            "  private final String string = optional.toString();",
+            "",
+            "  void m() {",
+            "    optional.orElseGet(() -> string + \"constant\");",
+            "    optional.orElseGet(\"constant\"::toString);",
+            "    optional.orElseGet(string::toString);",
+            "    optional.orElseGet(this.string::toString);",
+            "    optional.orElseGet(() -> String.valueOf(42));",
+            "    optional.orElseGet(() -> string.toString().length());",
+            "    optional.orElseGet(() -> string.equals(string));",
+            "    optional.orElseGet(() -> foo());",
+            "    optional.orElseGet(this::<Number>foo);",
+            "    optional.orElseGet(this::<String, Integer>bar);",
+            "    optional.orElseGet(() -> new Object() {});",
+            "    optional.orElseGet(() -> new int[0].length);",
+            "  }",
+            "",
+            "  private <T> T foo() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private <S, T> T bar() {",
+            "    return null;",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -1,6 +1,5 @@
 package tech.picnic.errorprone.bugpatterns;
 
-import com.google.common.collect.ImmutableList;
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
@@ -408,8 +407,7 @@ final class RedundantStringConversionTest {
   void identificationOfCustomConversionMethod() {
     CompilationTestHelper.newInstance(RedundantStringConversion.class, getClass())
         .setArgs(
-            ImmutableList.of(
-                "-XepOpt:RedundantStringConversion:ExtraConversionMethods=java.lang.Enum#name(),A#name(),A.B#toString(int)"))
+            "-XepOpt:RedundantStringConversion:ExtraConversionMethods=java.lang.Enum#name(),A#name(),A.B#toString(int)")
         .addSourceLines(
             "A.java",
             "import java.math.RoundingMode;",

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

@@ -0,0 +1,90 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class RedundantStringEscapeTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(RedundantStringEscape.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import java.util.Arrays;",
+            "import java.util.List;",
+            "",
+            "class A {",
+            "  List<String> m() {",
+            "    return Arrays.asList(",
+            "        \"foo\",",
+            "        \"ß\",",
+            "        \"'\",",
+            "        \"\\\"\",",
+            "        \"\\\\\",",
+            "        \"\\\\'\",",
+            "        \"'\\\\\",",
+            "        // BUG: Diagnostic contains:",
+            "        \"\\\\\\'\",",
+            "        // BUG: Diagnostic contains:",
+            "        \"\\'\\\\\",",
+            "        // BUG: Diagnostic contains:",
+            "        \"\\'\",",
+            "        // BUG: Diagnostic contains:",
+            "        \"'\\'\",",
+            "        // BUG: Diagnostic contains:",
+            "        \"\\''\",",
+            "        // BUG: Diagnostic contains:",
+            "        \"\\'\\'\",",
+            "        (",
+            "        // BUG: Diagnostic contains:",
+            "        /* Leading comment. */ \"\\'\" /* Trailing comment. */),",
+            "        // BUG: Diagnostic contains:",
+            "        \"\\'foo\\\"bar\\'baz\\\"qux\\'\");",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(RedundantStringEscape.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import java.util.Arrays;",
+            "import java.util.List;",
+            "",
+            "class A {",
+            "  List<String> m() {",
+            "    return Arrays.asList(",
+            "        \"\\'\",",
+            "        \"'\\'\",",
+            "        \"\\''\",",
+            "        \"\\'\\'\",",
+            "        \"\\'ß\\'\",",
+            "        (",
+            "        /* Leading comment. */ \"\\'\" /* Trailing comment. */),",
+            "        \"\\'foo\\\"bar\\'baz\\\"qux\\'\");",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import java.util.Arrays;",
+            "import java.util.List;",
+            "",
+            "class A {",
+            "  List<String> m() {",
+            "    return Arrays.asList(",
+            "        \"'\",",
+            "        \"''\",",
+            "        \"''\",",
+            "        \"''\",",
+            "        \"'ß'\",",
+            "        (",
+            "        /* Leading comment. */ \"'\" /* Trailing comment. */),",
+            "        \"'foo\\\"bar'baz\\\"qux'\");",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/Slf4jLogStatementTest.java

@@ -19,7 +19,6 @@ final class Slf4jLogStatementTest {
             "class A {",
             "  private static final String FMT0 = \"format-string-without-placeholders\";",
             "  private static final String FMT1 = \"format-string-with-{}-placeholder\";",
-            "  private static final String FMT2 = \"format-string-with-{}-{}-placeholders\";",
             "  private static final String FMT_ERR = \"format-string-with-%s-placeholder\";",
             "  private static final Logger LOG = LoggerFactory.getLogger(A.class);",
             "",

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/Slf4jLoggerDeclarationTest.java

@@ -0,0 +1,218 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class Slf4jLoggerDeclarationTest {
+  @Test
+  void identification() {
+    CompilationTestHelper.newInstance(Slf4jLoggerDeclaration.class, getClass())
+        .addSourceLines(
+            "A.java",
+            "import static java.lang.Class.forName;",
+            "",
+            "import org.slf4j.Logger;",
+            "import org.slf4j.LoggerFactory;",
+            "",
+            "class A {",
+            "  private static final long serialVersionUID = 1L;",
+            "  private static final Logger LOG = LoggerFactory.getLogger(A.class);",
+            "",
+            "  abstract static class DynamicLogger {",
+            "    private final Logger log = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "",
+            "  abstract static class DynamicLoggerWithExplicitThis {",
+            "    private final Logger log = LoggerFactory.getLogger(this.getClass());",
+            "  }",
+            "",
+            "  static final class StaticLogger {",
+            "    private static final Logger LOG = LoggerFactory.getLogger(StaticLogger.class);",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithCustomIdentifier {",
+            "    private static final Logger LOG = LoggerFactory.getLogger(\"custom-identifier\");",
+            "  }",
+            "",
+            "  interface StaticLoggerForInterface {",
+            "    Logger LOG = LoggerFactory.getLogger(StaticLoggerForInterface.class);",
+            "  }",
+            "",
+            "  abstract static class DynamicLoggerForWrongTypeWithoutReceiver {",
+            "    // BUG: Diagnostic contains:",
+            "    private final Logger log = LoggerFactory.getLogger(forName(\"A.class\"));",
+            "",
+            "    DynamicLoggerForWrongTypeWithoutReceiver() throws ClassNotFoundException {}",
+            "  }",
+            "",
+            "  abstract static class DynamicLoggerForWrongTypeWithoutSymbol {",
+            "    // BUG: Diagnostic contains:",
+            "    private final Logger log = LoggerFactory.getLogger(\"foo\".getClass());",
+            "  }",
+            "",
+            "  abstract static class DynamicLoggerForWrongTypeWithSymbol {",
+            "    // BUG: Diagnostic contains:",
+            "    private final Logger log = LoggerFactory.getLogger(new A().getClass());",
+            "  }",
+            "",
+            "  static final class NonAbstractDynamicLogger {",
+            "    // BUG: Diagnostic contains:",
+            "    private final Logger log = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "",
+            "  abstract static class DynamicLoggerWithMissingModifier {",
+            "    // BUG: Diagnostic contains:",
+            "    final Logger log = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "",
+            "  abstract static class DynamicLoggerWithExcessModifier {",
+            "    // BUG: Diagnostic contains:",
+            "    private final transient Logger log = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "",
+            "  abstract static class MisnamedDynamicLogger {",
+            "    // BUG: Diagnostic contains:",
+            "    private final Logger LOG = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithMissingModifier {",
+            "    // BUG: Diagnostic contains:",
+            "    static final Logger LOG = LoggerFactory.getLogger(StaticLoggerWithMissingModifier.class);",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithExcessModifier {",
+            "    // BUG: Diagnostic contains:",
+            "    private static final transient Logger LOG =",
+            "        LoggerFactory.getLogger(StaticLoggerWithExcessModifier.class);",
+            "  }",
+            "",
+            "  static final class MisnamedStaticLogger {",
+            "    // BUG: Diagnostic contains:",
+            "    private static final Logger log = LoggerFactory.getLogger(MisnamedStaticLogger.class);",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithIncorrectIdentifier {",
+            "    // BUG: Diagnostic contains:",
+            "    private static final Logger LOG = LoggerFactory.getLogger(A.class);",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithCustomIdentifierAndMissingModifier {",
+            "    // BUG: Diagnostic contains:",
+            "    static final Logger LOG = LoggerFactory.getLogger(\"custom-identifier\");",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithCustomIdentifierAndExcessModifier {",
+            "    // BUG: Diagnostic contains:",
+            "    private static final transient Logger LOG = LoggerFactory.getLogger(\"custom-identifier\");",
+            "  }",
+            "",
+            "  static final class MisnamedStaticLoggerWithCustomIdentifier {",
+            "    // BUG: Diagnostic contains:",
+            "    private static final Logger log = LoggerFactory.getLogger(\"custom-identifier\");",
+            "  }",
+            "",
+            "  interface StaticLoggerForInterfaceWithExcessModifier {",
+            "    // BUG: Diagnostic contains:",
+            "    static Logger LOG = LoggerFactory.getLogger(StaticLoggerForInterfaceWithExcessModifier.class);",
+            "  }",
+            "",
+            "  interface MisnamedStaticLoggerForInterface {",
+            "    // BUG: Diagnostic contains:",
+            "    Logger log = LoggerFactory.getLogger(MisnamedStaticLoggerForInterface.class);",
+            "  }",
+            "",
+            "  interface StaticLoggerForInterfaceWithIncorrectIdentifier {",
+            "    // BUG: Diagnostic contains:",
+            "    Logger LOG = LoggerFactory.getLogger(A.class);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    BugCheckerRefactoringTestHelper.newInstance(Slf4jLoggerDeclaration.class, getClass())
+        .addInputLines(
+            "A.java",
+            "import org.slf4j.Logger;",
+            "import org.slf4j.LoggerFactory;",
+            "",
+            "class A {",
+            "  static Logger foo = LoggerFactory.getLogger(Logger.class);",
+            "",
+            "  abstract static class DynamicLogger {",
+            "    transient Logger BAR = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "",
+            "  static final class StaticLogger {",
+            "    transient Logger baz = LoggerFactory.getLogger(LoggerFactory.class);",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithCustomIdentifier {",
+            "    transient Logger qux = LoggerFactory.getLogger(\"custom-identifier\");",
+            "  }",
+            "",
+            "  interface StaticLoggerForInterface {",
+            "    public static final Logger quux = LoggerFactory.getLogger(A.class);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import org.slf4j.Logger;",
+            "import org.slf4j.LoggerFactory;",
+            "",
+            "class A {",
+            "  private static final Logger LOG = LoggerFactory.getLogger(A.class);",
+            "",
+            "  abstract static class DynamicLogger {",
+            "    private final Logger log = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "",
+            "  static final class StaticLogger {",
+            "    private static final Logger LOG = LoggerFactory.getLogger(StaticLogger.class);",
+            "  }",
+            "",
+            "  static final class StaticLoggerWithCustomIdentifier {",
+            "    private static final Logger LOG = LoggerFactory.getLogger(\"custom-identifier\");",
+            "  }",
+            "",
+            "  interface StaticLoggerForInterface {",
+            "    Logger LOG = LoggerFactory.getLogger(StaticLoggerForInterface.class);",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+
+  @Test
+  void replacementWithCustomLoggerName() {
+    BugCheckerRefactoringTestHelper.newInstance(Slf4jLoggerDeclaration.class, getClass())
+        .setArgs("-XepOpt:Slf4jLoggerDeclaration:CanonicalStaticLoggerName=FOO_BAR")
+        .addInputLines(
+            "A.java",
+            "import org.slf4j.Logger;",
+            "import org.slf4j.LoggerFactory;",
+            "",
+            "class A {",
+            "  transient Logger LOG = LoggerFactory.getLogger(Logger.class);",
+            "",
+            "  abstract static class DynamicLogger {",
+            "    transient Logger log = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import org.slf4j.Logger;",
+            "import org.slf4j.LoggerFactory;",
+            "",
+            "class A {",
+            "  private static final Logger FOO_BAR = LoggerFactory.getLogger(A.class);",
+            "",
+            "  abstract static class DynamicLogger {",
+            "    private final Logger fooBar = LoggerFactory.getLogger(getClass());",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -36,6 +36,7 @@ final class RefasterRulesTest {
           AssortedRules.class,
           BigDecimalRules.class,
           BugCheckerRules.class,
+          CharSequenceRules.class,
           ClassRules.class,
           CollectionRules.class,
           ComparatorRules.class,
@@ -43,6 +44,7 @@ final class RefasterRulesTest {
           EqualityRules.class,
           FileRules.class,
           InputStreamRules.class,
+          ImmutableEnumSetRules.class,
           ImmutableListRules.class,
           ImmutableListMultimapRules.class,
           ImmutableMapRules.class,
@@ -58,6 +60,7 @@ final class RefasterRulesTest {
           LongStreamRules.class,
           MapEntryRules.class,
           MapRules.class,
+          MicrometerRules.class,
           MockitoRules.class,
           MultimapRules.class,
           NullRules.class,