[maven-release-plugin] prepare release v0.3.0

For performance reasons, the Javadoc JARs are not generated when executing `mvn
install`. They are generally only compiled when running `mvn release:perform`,
as part of the `release` Maven profile.

The downside of this setup is that Javadoc generation issues may not be caught
until release time. This change resolves such an issue. To prevent future
regressions, Javadoc generation is now also performed by the GitHub Actions
build workflow.

While there, drop the deprecated `useReleaseProfile` configuration setting of
the javadoc-maven-plugin, as its value matches the default.

.github/release.yml

@@ -0,0 +1,29 @@
+changelog:
+  exclude:
+    labels:
+      - "ignore-changelog"
+  categories:
+    - title: ":rocket: New Error Prone checks and Refaster templates"
+      labels:
+        - "new feature"
+    - title: ":sparkles: Improvements"
+      labels:
+        - "improvement"
+    - title: ":warning: Update considerations and deprecations"
+      labels:
+        - "breaking change"
+        - "deprecation"
+    - title: ":bug: Bug fixes"
+      labels:
+        - "bug"
+        - "bug fix"
+    - title: ":books: Documentation, test and build improvements"
+      labels:
+        - "documentation"
+        - "chore"
+    - title: ":chart_with_upwards_trend: Dependency upgrades"
+      labels:
+        - "dependencies"
+    - title: "Other changes"
+      labels:
+        - "*"

.github/workflows/build.yaml

@@ -0,0 +1,39 @@
+name: Build and verify
+on:
+  pull_request:
+  push:
+    branches:
+      - 'master'
+permissions:
+  contents: read
+jobs:
+  build:
+    runs-on: ubuntu-22.04
+    strategy:
+      matrix:
+        jdk: [ 11.0.16, 17.0.4 ]
+    steps:
+        # We run the build twice for each supported JDK: once against the
+        # original Error Prone release, using only Error Prone checks available
+        # on Maven Central, and once against the Picnic Error Prone fork,
+        # additionally enabling all checks defined in this project and any
+        # Error Prone checks available only from other artifact repositories.
+      - name: Check out code
+        uses: actions/checkout@v3.0.2
+      - name: Set up JDK
+        uses: actions/setup-java@v3.4.1
+        with:
+          java-version: ${{ matrix.jdk }}
+          distribution: temurin
+          cache: maven
+      - name: Display build environment details
+        run: mvn --version
+      - name: Build project against vanilla Error Prone, compile Javadoc
+        run: mvn -T1C install javadoc:jar
+      - name: Build project with self-check against Error Prone fork
+        run: mvn -T1C clean verify -Perror-prone-fork -Pnon-maven-central -Pself-check -s settings.xml
+      - name: Remove installed project artifacts
+        run: mvn build-helper:remove-project-artifact
+
+# XXX: Enable Codecov once we "go public".
+# XXX: Enable SonarCloud once we "go public".

.mvn/jvm.config

@@ -1,4 +1,8 @@
+-XX:ReservedCodeCacheSize=512m
+-XX:SoftRefLRUPolicyMSPerMB=10
+-XX:+UseParallelGC
 --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED
+--add-exports=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
 --add-exports=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED
 --add-exports=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED
 --add-exports=jdk.compiler/com.sun.tools.javac.model=ALL-UNNAMED
@@ -6,5 +10,4 @@
 --add-exports=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED
 --add-exports=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED
 --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED
---add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED
 --add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED

.mvn/maven.config

@@ -0,0 +1 @@
+--batch-mode --errors --strict-checksums

.renovaterc.json

@@ -0,0 +1,22 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "packageRules": [
+    {
+      "matchPackagePatterns": [
+        "^org\\.springframework:spring-framework-bom$",
+        "^org\\.springframework\\.boot:spring-boot[a-z-]*$"
+      ],
+      "separateMinorPatch": true
+    },
+    {
+      "matchPackagePatterns": [
+        "^com\\.palantir\\.baseline:baseline-error-prone$"
+      ],
+      "schedule": "* * 1 * *"
+    }
+  ],
+  "reviewers": [
+    "rickie",
+    "Stephan202"
+  ]
+}

.travis.yml

@@ -1,38 +0,0 @@
----
-dist: bionic
-language: java
-jdk: openjdk11
-addons:
-  sonarcloud:
-    organization: picnic-technologies
-    token: "${SONARCLOUD_TOKEN}"
-install:
-  - mvn io.takari:maven:wrapper
-script:
-  # We run the build twice: once against the original Error Prone release,
-  # using only Error Prone checks available on Maven Central, and once against
-  # the Picnic Error Prone fork, additionally enabling all checks defined in
-  # this project and any Error Prone checks available only from other artifact
-  # repositories.
-  - ./mvnw clean install
-  - ./mvnw clean install -Perror-prone-fork -Pnon-maven-central -Pself-check -s settings.xml
-  # XXX: Enable SonarCloud once we "go public".
-  # ./mvnw jacoco:prepare-agent surefire:test jacoco:report sonar:sonar
-  - ./mvnw jacoco:prepare-agent surefire:test jacoco:report
-before_cache:
-  # Don't cache the artifacts we just generated, for multiple reasons: (1) we
-  # shouldn't need them next time around and (2) if we do, that indicates a
-  # dependency issue which might otherwise go unnoticed until next time we bump
-  # the project's version (i.e., when tagging).
-  - find "${HOME}/.m2/repository" -depth -name '*-SNAPSHOT' -exec rm -r '{}' \;
-cache:
-  directories:
-    # The local Maven repository in which third party dependencies are stored.
-    - ${HOME}/.m2/repository
-    # The Takari Maven Wrapper's storage for downloaded Maven distributions.
-    - ${HOME}/.m2/wrapper
-    # The SonarQube analysis cache.
-    - ${HOME}/.sonar/cache
-# XXX: Enable Codecov once we "go public".
-#after_success:
-#  - bash <(curl -s https://codecov.io/bash)

CONTRIBUTING.md

@@ -0,0 +1,71 @@
+# Contributing
+
+Thank you for checking this document! This project is free software, and we
+(the maintainers) encourage and value any contribution.
+
+Here are some guidelines to help you get started.
+
+## 🐛 Reporting a bug
+
+Like any non-trivial piece of software, this library is probably not bug-free.
+If you found a bug, feel free to [report the issue][error-prone-support-issues]
+on GitHub.
+
+Before doing so, please:
+- Verify that the issue is reproducible against the latest version of the
+  project.
+- Search through the existing set of issues to see whether the problem is
+  already known. With some luck a solution is already in place, or a workaround
+  may have been provided.
+
+When filing a bug report, please include the following:
+- Any relevant information about your environment. This should generally
+  include the output of `java -version`, as well as the version of Error Prone
+  you're using.
+- A description of what is going on (e.g. logging output, stacktraces).
+- A minimum reproducible example, so that other developers can try to reproduce
+  (and optionally fix) the bug.
+- Any additional information that may be relevant.
+
+## 💡 Reporting an improvement
+
+If you would like to see an improvement, you can file a [GitHub
+issue][error-prone-support-issues]. This is also a good idea when you're
+already working towards opening a pull request, as this allows for discussion
+around the idea.
+
+## 🚀 Opening a pull request
+
+All submissions, including submissions by project members, require approval by
+at least two reviewers. We use [GitHub pull
+requests][error-prone-support-pulls] for this purpose.
+
+Before opening a pull request, please check whether there are any existing
+(open or closed) issues or pull requests addressing the same problem. This
+avoids double work or lots of time spent on a solution that may ultimately not
+be accepted. When in doubt, make sure to first raise an
+[issue][error-prone-support-issues] to discuss the idea.
+
+To the extent possible, the pull request process guards our coding guidelines.
+Some pointers:
+- Checks should be _topical_: ideally they address a single concern.
+- Where possible checks should provide _fixes_, and ideally these are
+  completely behavior-preserving. In order for a check to be adopted by users
+  it must not "get in the way". So for a check which addresses a relatively
+  trivial stylistic concern it is doubly important that the violations it
+  detects can be auto-patched.
+- Make sure you have read Error Prone's [criteria for new
+  checks][error-prone-criteria]. Most guidelines described there apply to this
+  project as well, except that this project _does_ focus quite heavy on style
+  enforcement. But that just makes the previous point doubly important.
+- Make sure that a check's [(mutation) test
+  coverage][error-prone-support-mutation-tests] is or remains about as high as
+  it can be. Not only does this lead to better tests, it also points out
+  opportunities to simplify the code.
+- Please restrict the scope of a pull request to a single feature or fix. Don't
+  sneak in unrelated changes; instead just open more than one pull request 😉.
+
+[error-prone-criteria]: https://errorprone.info/docs/criteria
+[error-prone-support-issues]: https://github.com/PicnicSupermarket/error-prone-support/issues
+[error-prone-support-mutation-tests]: https://github.com/PicnicSupermarket/error-prone-support/blob/master/run-mutation-tests.sh
+[error-prone-support-pulls]: https://github.com/PicnicSupermarket/error-prone-support/pulls

LICENSE.md

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2017-2022 Picnic Technologies BV
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

README.md

@@ -0,0 +1,224 @@
+<div align="center">
+
+<picture>
+  <source media="(prefers-color-scheme: dark)" srcset="logo-dark.svg">
+  <source media="(prefers-color-scheme: light)" srcset="logo.svg">
+  <img alt="Error Prone Support logo" src="logo.svg" width="50%">
+</picture>
+
+# Error Prone Support
+
+Error Prone Support is a Picnic-opinionated extension of Google's [Error
+Prone][error-prone-orig-repo]. It aims to improve code quality, focussing on
+maintainability, consistency and avoidance of common gotchas.
+
+> Error Prone is a static analysis tool for Java that catches common
+> programming mistakes at compile-time.
+
+[![Maven Central][maven-central-badge]][maven-central-search]
+[![GitHub Actions][github-actions-build-badge]][github-actions-build-master]
+[![License][license-badge]][license]
+[![PRs Welcome][pr-badge]][contributing]
+
+[Getting started](#-getting-started) • [Building](#-building) •
+[How it works](#-how-it-works) • [Contributing](#%EF%B8%8F-contributing)
+
+</div>
+
+---
+
+## ⚡ Getting started
+
+### Installation
+
+This library is built on top of [Error Prone][error-prone-orig-repo]. To use
+it:
+
+1. First, follow Error Prone's [installation
+   guide][error-prone-installation-guide].
+2. Next, edit your `pom.xml` file to add one or more Error Prone Support
+   modules to the `annotationProcessorPaths` of the `maven-compiler-plugin`:
+
+   ```xml
+   <build>
+       <pluginManagement>
+           <plugins>
+               <plugin>
+                   <groupId>org.apache.maven.plugins</groupId>
+                   <artifactId>maven-compiler-plugin</artifactId>
+                   <configuration>
+                       <annotationProcessorPaths>
+                           <!-- Error Prone itself. -->
+                           <path>
+                               <groupId>com.google.errorprone</groupId>
+                               <artifactId>error_prone_core</artifactId>
+                               <version>${error-prone.version}</version>
+                           </path>
+                           <!-- Error Prone Support's additional bug checkers. -->
+                           <path>
+                               <groupId>tech.picnic.error-prone-support</groupId>
+                               <artifactId>error-prone-contrib</artifactId>
+                               <version>${error-prone-support.version}</version>
+                           </path>
+                           <!-- Error Prone Support's Refaster templates. -->
+                           <path>
+                               <groupId>tech.picnic.error-prone-support</groupId>
+                               <artifactId>refaster-runner</artifactId>
+                               <version>${error-prone-support.version}</version>
+                           </path>
+                       </annotationProcessorPaths>
+                       <compilerArgs>
+                           <arg>
+                               -Xplugin:ErrorProne
+                               <!-- Add other Error Prone flags here. See
+                               https://errorprone.info/docs/flags. -->
+                           </arg>
+                           <arg>-XDcompilePolicy=simple</arg>
+                       </compilerArgs>
+                       <!-- Some checks raise warnings rather than errors. -->
+                       <showWarnings>true</showWarnings>
+                       <!-- Enable this if you'd like to fail your build upon warnings. -->
+                       <!-- <failOnWarning>true</failOnWarning> -->
+                   </configuration>
+               </plugin>
+           </plugins>
+       </pluginManagement>
+   </build>
+   ```
+
+<!-- XXX: Reference `oss-parent`'s `pom.xml` once that project also uses Error
+Prone Support. Alternatively reference this project's `self-check` profile
+definition. -->
+
+### Seeing it in action
+
+Consider the following example code:
+
+```java
+import com.google.common.collect.ImmutableSet;
+import java.math.BigDecimal;
+
+public class Example {
+  static BigDecimal getNumber() {
+    return BigDecimal.valueOf(0);
+  }
+
+  public ImmutableSet<Integer> getSet() {
+    ImmutableSet<Integer> set = ImmutableSet.of(1);
+    return ImmutableSet.copyOf(set);
+  }
+}
+```
+
+If the [installation](#installation) was successful, then building the above
+code with Maven should yield two compiler warnings:
+
+```sh
+$ mvn clean install
+...
+[INFO] -------------------------------------------------------------
+[WARNING] COMPILATION WARNING :
+[INFO] -------------------------------------------------------------
+[WARNING] Example.java:[9,34] [tech.picnic.errorprone.refastertemplates.BigDecimalTemplates.BigDecimalZero]
+  Did you mean 'return BigDecimal.ZERO;'?
+[WARNING] Example.java:[14,35] [IdentityConversion] This method invocation appears redundant; remove it or suppress this warning and add a comment explaining its purpose
+  Did you mean 'return set;' or '@SuppressWarnings("IdentityConversion") public ImmutableSet<Integer> getSet() {'?
+[INFO] 2 warnings
+[INFO] -------------------------------------------------------------
+...
+```
+
+Two things are kicking in here:
+
+1. An Error Prone [`BugChecker`][error-prone-bugchecker] that flags unnecessary
+   [identity conversions][bug-checks-identity-conversion].
+2. A [Refaster][refaster] template capable of
+   [rewriting][refaster-templates-bigdecimal] expressions of the form
+   `BigDecimal.valueOf(0)` and `new BigDecimal(0)` to `BigDecimal.ZERO`.
+
+Be sure to check out all [bug checks][bug-checks] and [refaster
+templates][refaster-templates].
+
+## 👷 Building
+
+This is a [Maven][maven] project, so running `mvn clean install`
+performs a full clean build. Some relevant flags:
+
+- `-Dverification.warn` makes the warnings and errors emitted by various
+  plugins and the Java compiler non-fatal, where possible.
+- `-Dverification.skip` disables various non-essential plugins and compiles the
+  code with minimal checks (i.e. without linting, Error Prone checks, etc.).
+- `-Dversion.error-prone=some-version` runs the build using the specified
+  version of Error Prone. This is useful e.g. when testing a locally built
+  Error Prone SNAPSHOT.
+- `-Perror-prone-fork` runs the build using Picnic's [Error Prone
+  fork][error-prone-fork-repo], hosted on [Jitpack][error-prone-fork-jitpack].
+  This fork generally contains a few changes on top of the latest Error Prone
+  release.
+- `-Pself-check` runs the checks defined by this project against itself.
+  Pending a release of [google/error-prone#3301][error-prone-pull-3301], this
+  flag must currently be used in combination with `-Perror-prone-fork`.
+
+Some other commands one may find relevant:
+
+- `mvn fmt:format` formats the code using
+  [`google-java-format`][google-java-format].
+- `./run-mutation-tests.sh` runs mutation tests using [PIT][pitest]. The
+  results can be reviewed by opening the respective
+  `target/pit-reports/index.html` files. For more information check the [PIT
+  Maven plugin][pitest-maven].
+- `./apply-error-prone-suggestions.sh` applies Error Prone and Error Prone
+  Support code suggestions to this project. Before running this command, make
+  sure to have installed the project (`mvn clean install`) and make sure that
+  the current working directory does not contain unstaged or uncommited
+  changes.
+
+When running the project's tests in IntelliJ IDEA, you might see the following
+error:
+
+```
+java: exporting a package from system module jdk.compiler is not allowed with --release
+```
+
+If this happens, go to _Settings -> Build, Execution, Deployment -> Compiler ->
+Java Compiler_ and deselect the option _Use '--release' option for
+cross-compilation (Java 9 and later)_. See [IDEA-288052][idea-288052] for
+details.
+
+## 💡 How it works
+
+This project provides additional [`BugChecker`][error-prone-bugchecker]
+implementations.
+
+<!-- XXX: Extend this section. -->
+
+## ✍️ Contributing
+
+Want to report or fix a bug, suggest or add a new feature, or improve the
+documentation? That's awesome! Please read our [contribution
+guidelines][contributing].
+
+[bug-checks]: error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/
+[bug-checks-identity-conversion]: error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/IdentityConversion.java
+[contributing]: CONTRIBUTING.md
+[error-prone-bugchecker]: https://github.com/google/error-prone/blob/master/check_api/src/main/java/com/google/errorprone/bugpatterns/BugChecker.java
+[error-prone-fork-jitpack]: https://jitpack.io/#PicnicSupermarket/error-prone
+[error-prone-fork-repo]: https://github.com/PicnicSupermarket/error-prone
+[error-prone-installation-guide]: https://errorprone.info/docs/installation#maven
+[error-prone-orig-repo]: https://github.com/google/error-prone
+[error-prone-pull-3301]: https://github.com/google/error-prone/pull/3301
+[github-actions-build-badge]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/build.yaml/badge.svg
+[github-actions-build-master]: https://github.com/PicnicSupermarket/error-prone-support/actions/workflows/build.yaml?query=branch%3Amaster
+[google-java-format]: https://github.com/google/google-java-format
+[idea-288052]: https://youtrack.jetbrains.com/issue/IDEA-288052
+[license-badge]: https://img.shields.io/github/license/PicnicSupermarket/error-prone-support
+[license]: LICENSE.md
+[maven-central-badge]: https://img.shields.io/maven-central/v/tech.picnic.error-prone-support/error-prone-support?color=blue
+[maven-central-search]: https://search.maven.org/artifact/tech.picnic.error-prone-support/error-prone-support
+[maven]: https://maven.apache.org
+[pitest]: https://pitest.org
+[pitest-maven]: https://pitest.org/quickstart/maven
+[pr-badge]: https://img.shields.io/badge/PRs-welcome-brightgreen.svg
+[refaster]: https://errorprone.info/docs/refaster
+[refaster-templates-bigdecimal]: error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/BigDecimalTemplates.java
+[refaster-templates]: error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/

apply-error-prone-suggestions.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+# Compiles the code using Error Prone and applies its suggestions. The set of
+# checks applied can optionally be restricted by name.
+#
+# As this script may modify the project's code, it is important to execute it
+# in a clean Git working directory.
+
+set -e -u -o pipefail
+
+if [ "${#}" -gt 1 ]; then
+  echo "Usage: ./$(basename "${0}") [PatchChecks]"
+  exit 1
+fi
+
+patchChecks=${1:-}
+
+mvn clean test-compile fmt:format \
+  -T 1.0C \
+  -Perror-prone \
+  -Perror-prone-fork \
+  -Ppatch \
+  -Pself-check \
+  -Derror-prone.patch-checks="${patchChecks}" \
+  -Dverification.skip

error-prone-contrib/README.md

@@ -11,71 +11,22 @@ request.
 
 ### Building
 
-This is a [Maven][maven] project, so running `mvn clean install` performs a
-full clean build. Some relevant flags:
-- `-Dverification.warn` makes the warnings and errors emitted by various
-  plugins and the Java compiler non-fatal, where possible.
-- `-Dverification.skip` disables various non-essential plugins and compiles the
-  code with minimal checks (i.e. without linting, Error Prone checks, etc.)
-- `-Dversion.error-prone=some-version` runs the build using the specified
-  version of Error Prone. This is useful e.g. when testing a locally built
-  Error Prone SNAPSHOT.
-- `-Perror-prone-fork` run the build using Picnic's [Error Prone
-  fork][error-prone-fork-repo], hosted on [Jitpack][error-prone-fork-jitpack].
-  This fork generally contains a few changes on top of the latest Error Prone
-  release.
-
-Two other goals that one may find relevant:
-- `mvn fmt:format` formats the code using
-  [`google-java-format`][google-java-format].
-- `mvn pitest:mutationCoverage` runs mutation tests using [PIT][pitest]. The
-  results can be reviewed by opening the respective
-  `target/pit-reports/index.html` files. For more information check the [PIT
-  Maven plugin][pitest-maven].
-
-When loading the project in IntelliJ IDEA (and perhaps other IDEs) errors about
-the inaccessibility of `com.sun.tools.javac.*` classes may be reported. If this
-happens, configure your IDE to enable the `add-exports` profile.
+See the main [readme][main-readme].
 
 ### Contribution guidelines
 
-To the extend possible, the pull request process guards our coding guidelines.
-Some pointers:
-- Checks should we _topical_: Ideally they address a single concern.
-- Where possible checks should provide _fixes_, and ideally these are
-  completely behavior preserving. In order for a check to be adopted by users
-  it must not "get in the way". So for a check which addresses a relatively
-  trivial stylistic concern it is doubly important that the violations it
-  detects can be auto-patched.
-- Make sure you have read Error Prone's [criteria for new
-  checks][error-prone-criteria]. Most guidelines described there apply to this
-  project as well, except that this project _does_ focus quite heavy on style
-  enforcement. But that just makes the previous point doubly important.
-- Make sure that a check's (mutation) coverage is or remains about as high as
-  it can be. Not only does this lead to better tests, it also points out
-  opportunities to simplify the code.
-- Please restrict the scope of a pull request to a single feature or fix. Don't
-  sneak in unrelated changes.
-- When in doubt about whether a pull request will be accepted, please first
-  file an issue to discuss it.
+See our [contributing guidelines][main-contributing].
 
 ### Our wishlist
 
 We expect the following tasks to help improve the quality of this open source
 project:
 
-- Publish the artifact to Maven Central, then document the coordinates in this
-  `README.md`.
-- Document how to enable the checks.
 - Document how to apply patches.
 - Document each of the checks.
-- Add Travis CI, [SonarQube][sonarcloud] and [Codecov][codecov]
-  integrations.
-- Investigate whether it makes sense to include license headers in each file.
-  If so, set that up and enforce it.
+- Add [SonarQube][sonarcloud] and [Codecov][codecov] integrations.
 - Add non-Java file formatting support, like we have internally at Picnic.
   (I.e., somehow open-source that stuff.)
-- Add relevant "badges" at the top of this `README.md`.
 - Auto-generate a website listing each of the checks, just like the Error Prone
   [bug patterns page][error-prone-bug-patterns]. The [Error Prone
   repository][error-prone-repo] contains code for this.
@@ -93,7 +44,7 @@ project:
 - Improve an existing check (see `XXX`-marked comments in the code) or write a
   new one (see the list of suggestions below).
 
-### Ideas for new checks
+### BugChecker extension ideas
 
 The following is a list of checks we'd like to see implemented:
 
@@ -118,12 +69,13 @@ The following is a list of checks we'd like to see implemented:
   code and Javadoc `@link` references.
 - A check which simplifies array expressions. It would replace empty array
   expressions of the form `new int[] {}` with `new int[0]`. Statements of the
-  form `byte[] arr = new byte[] {'c'};` would be shortened to `byte[] arr =
-  {'c'};`.
-- A check which replaces expressions of the form `String.format("some prefix
-  %s", arg)` with `"some prefix " + arg`, and similar for simple suffixes. Can
-  perhaps be generalized further, though it's unclear how far. (Well, a
-  `String.format` call without arguments can certainly be simplified, too.)
+  form `byte[] arr = new byte[] {'c'};` would be shortened to
+  `byte[] arr = {'c'};`.
+- A check which replaces expressions of the form
+  `String.format("some prefix %s", arg)` with `"some prefix " + arg`, and
+  similar for simple suffixes. Can perhaps be generalized further, though it's
+  unclear how far. (Well, a `String.format` call without arguments can
+  certainly be simplified, too.)
 - A check which replaces single-character strings with `char`s where possible.
   For example as argument to `StringBuilder.append` and in string
   concatenations.
@@ -168,11 +120,11 @@ The following is a list of checks we'd like to see implemented:
 - A check which flags imports from other test classes.
 - A Guava-specific check which replaces `Joiner.join` calls with `String.join`
   calls in those cases where the latter is a proper substitute for the former.
-- A Guava-specific check which flags `{Immutable,}Multimap` type usages
-  where `{Immutable,}{List,Set}Multimap` would be more appropriate.
-- A Guava-specific check which rewrites `if (conditional) { throw new
-  IllegalArgumentException(); }` and variants to an equivalent `checkArgument`
-  statement. Idem for other exception types.
+- A Guava-specific check which flags `{Immutable,}Multimap` type usages where
+  `{Immutable,}{List,Set}Multimap` would be more appropriate.
+- A Guava-specific check which rewrites
+  `if (conditional) { throw new IllegalArgumentException(); }` and variants to
+  an equivalent `checkArgument` statement. Idem for other exception types.
 - A Guava-specific check which replaces simple anonymous `CacheLoader` subclass
   declarations with `CacheLoader.from(someLambda)`.
 - A Spring-specific check which enforces that methods with the `@Scheduled`
@@ -247,6 +199,7 @@ but on the flip side Refaster is much less expressive. While this gap can never
 be fully closed, there are some ways in which Refaster's scope of utility could
 be extended. The following is a non-exhaustive list of ideas on how to extend
 Refaster's expressiveness:
+
 - Allow more control over _which_ methods are statically imported by
   `@UseImportPolicy`. Sometimes the `@AfterTemplate` contains more than one
   static method invocation, and only a subset should be statically imported.
@@ -259,16 +212,16 @@ Refaster's expressiveness:
 - Some Refaster refactorings (e.g. when dealing with lazy evaluation) are valid
   only when some free parameter is a constant, variable reference or some other
   pure expression. Introduce a way to express such a constraint. For example,
-  rewriting `optional1.map(Optional::of).orElse(optional2)` to `optional1.or(()
-  -> optional2)` is not behavior preserving if evaluation of `optional2` has
-  side-effects.
+  rewriting `optional1.map(Optional::of).orElse(optional2)` to
+  `optional1.or(() -> optional2)` is not behavior preserving if evaluation of
+  `optional2` has side-effects.
 - Similarly, certain refactoring operations are only valid if one of the
   matches expressions is not `@Nullable`. It'd be nice to be able to express
   this.
 - Generalize `@Placeholder` support such that rules can reference e.g. "any
   concrete unary method". This would allow refactorings such as
-  `Mono.just(constant).flatmap(this::someFun)` -> `Mono.defer(() ->
-  someFun(constant))`.
+  `Mono.just(constant).flatmap(this::someFun)` ->
+  `Mono.defer(() -> someFun(constant))`.
 - Sometimes a Refaster refactoring can cause the resulting code not to compile
   due to a lack of generic type information. Identify and resolve such
   occurrences. For example, an `@AfterTemplate` may require the insertion of a
@@ -327,16 +280,12 @@ Refaster's expressiveness:
 [checkstyle-external-project-tests]: https://github.com/checkstyle/checkstyle/blob/master/wercker.yml
 [codecov]: https://codecov.io
 [error-prone-bug-patterns]: https://errorprone.info/bugpatterns
-[error-prone-criteria]: https://errorprone.info/docs/criteria
-[error-prone-fork-jitpack]: https://jitpack.io/#PicnicSupermarket/error-prone
-[error-prone-fork-repo]: https://github.com/PicnicSupermarket/error-prone
 [error-prone]: https://errorprone.info
 [error-prone-repo]: https://github.com/google/error-prone
 [forbidden-apis]: https://github.com/policeman-tools/forbidden-apis
 [fossa]: https://fossa.io
 [google-java-format]: https://github.com/google/google-java-format
-[maven]: https://maven.apache.org
+[main-contributing]: ../CONTRIBUTING.md
+[main-readme]: ../README.md
 [modernizer-maven-plugin]: https://github.com/gaul/modernizer-maven-plugin
 [sonarcloud]: https://sonarcloud.io
-[pitest]: https://pitest.org
-[pitest-maven]: https://pitest.org/quickstart/maven

error-prone-contrib/pom.xml

@@ -5,7 +5,7 @@
     <parent>
         <groupId>tech.picnic.error-prone-support</groupId>
         <artifactId>error-prone-support</artifactId>
-        <version>0.0.1-SNAPSHOT</version>
+        <version>0.3.0</version>
     </parent>
 
     <artifactId>error-prone-contrib</artifactId>
@@ -41,15 +41,13 @@
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
-            <artifactId>refaster-compiler</artifactId>
-            <!-- This dependency is declared only as a hint to Maven that
-            compilation depends on it; see the `maven-compiler-plugin`'s
-            `annotationProcessorPaths` configuration below. -->
+            <artifactId>refaster-support</artifactId>
             <scope>provided</scope>
         </dependency>
         <dependency>
             <groupId>${project.groupId}</groupId>
-            <artifactId>refaster-support</artifactId>
+            <artifactId>refaster-test-support</artifactId>
+            <scope>test</scope>
         </dependency>
         <dependency>
             <groupId>com.fasterxml.jackson.core</groupId>
@@ -72,9 +70,8 @@
             <scope>provided</scope>
         </dependency>
         <dependency>
-            <groupId>com.google.errorprone</groupId>
-            <artifactId>javac</artifactId>
-            <scope>provided</scope>
+            <groupId>com.google.googlejavaformat</groupId>
+            <artifactId>google-java-format</artifactId>
         </dependency>
         <dependency>
             <groupId>com.google.guava</groupId>
@@ -136,6 +133,16 @@
             <artifactId>assertj-core</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.immutables</groupId>
+            <artifactId>value-annotations</artifactId>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.jspecify</groupId>
+            <artifactId>jspecify</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-api</artifactId>
@@ -171,6 +178,11 @@
             <artifactId>spring-test</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>org.springframework</groupId>
+            <artifactId>spring-web</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.springframework</groupId>
             <artifactId>spring-webflux</artifactId>
@@ -191,15 +203,6 @@
     <build>
         <pluginManagement>
             <plugins>
-                <plugin>
-                    <groupId>com.spotify.fmt</groupId>
-                    <artifactId>fmt-maven-plugin</artifactId>
-                    <configuration>
-                        <additionalSourceDirectories>
-                            <additionalSourceDirectory>${basedir}/src/test/resources</additionalSourceDirectory>
-                        </additionalSourceDirectories>
-                    </configuration>
-                </plugin>
                 <plugin>
                     <groupId>org.apache.maven.plugins</groupId>
                     <artifactId>maven-compiler-plugin</artifactId>

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

@@ -25,12 +25,11 @@ import javax.lang.model.element.AnnotationValue;
 /** A {@link BugChecker} which flags ambiguous {@code @JsonCreator}s in enums. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "AmbiguousJsonCreator",
     summary = "`JsonCreator.Mode` should be set for single-argument creators",
     linkType = NONE,
     severity = WARNING,
     tags = LIKELY_ERROR)
-public final class AmbiguousJsonCreatorCheck extends BugChecker implements AnnotationTreeMatcher {
+public final class AmbiguousJsonCreator extends BugChecker implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<AnnotationTree> IS_JSON_CREATOR_ANNOTATION =
       isType("com.fasterxml.jackson.annotation.JsonCreator");

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

@@ -0,0 +1,57 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.argument;
+import static com.google.errorprone.matchers.Matchers.argumentCount;
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+import static com.google.errorprone.matchers.Matchers.nullLiteral;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.MethodInvocationTree;
+
+/**
+ * A {@link BugChecker} which flags AssertJ {@code isEqualTo(null)} checks for simplification.
+ *
+ * <p>This bug checker cannot be replaced with a simple Refaster template, as the Refaster approach
+ * would require that all overloads of {@link org.assertj.core.api.Assert#isEqualTo(Object)} (such
+ * as {@link org.assertj.core.api.AbstractStringAssert#isEqualTo(String)}) are explicitly
+ * enumerated. This bug checker generically matches all such current and future overloads.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Prefer `.isNull()` over `.isEqualTo(null)`",
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = SIMPLIFICATION)
+public final class AssertJIsNull extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<MethodInvocationTree> ASSERT_IS_EQUAL_TO_NULL =
+      allOf(
+          instanceMethod().onDescendantOf("org.assertj.core.api.Assert").named("isEqualTo"),
+          argumentCount(1),
+          argument(0, nullLiteral()));
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!ASSERT_IS_EQUAL_TO_NULL.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    SuggestedFix.Builder fix =
+        SuggestedFix.builder().merge(SuggestedFixes.renameMethodInvocation(tree, "isNull", state));
+    tree.getArguments().forEach(arg -> fix.merge(SuggestedFix.delete(arg)));
+
+    return describeMatch(tree, fix.build());
+  }
+}

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

@@ -8,6 +8,7 @@ import static com.google.errorprone.matchers.Matchers.annotations;
 import static com.google.errorprone.matchers.Matchers.isType;
 
 import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.VisitorState;
@@ -26,12 +27,11 @@ import java.util.List;
 /** A {@link BugChecker} which flags redundant {@code @Autowired} constructor annotations. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "AutowiredConstructor",
     summary = "Omit `@Autowired` on a class' sole constructor, as it is redundant",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class AutowiredConstructorCheck extends BugChecker implements ClassTreeMatcher {
+public final class AutowiredConstructor extends BugChecker implements ClassTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final MultiMatcher<Tree, AnnotationTree> AUTOWIRED_ANNOTATION =
       annotations(AT_LEAST_ONE, isType("org.springframework.beans.factory.annotation.Autowired"));
@@ -43,7 +43,7 @@ public final class AutowiredConstructorCheck extends BugChecker implements Class
       return Description.NO_MATCH;
     }
 
-    List<AnnotationTree> annotations =
+    ImmutableList<AnnotationTree> annotations =
         AUTOWIRED_ANNOTATION
             .multiMatchResult(Iterables.getOnlyElement(constructors), state)
             .matchingNodes();

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

@@ -25,25 +25,24 @@ import java.util.Optional;
 import java.util.function.BiFunction;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} which flags annotations that could be written more concisely. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "CanonicalAnnotationSyntax",
     summary = "Omit redundant syntax from annotation declarations",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class CanonicalAnnotationSyntaxCheck extends BugChecker
-    implements AnnotationTreeMatcher {
+public final class CanonicalAnnotationSyntax extends BugChecker implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Pattern TRAILING_ARRAY_COMMA = Pattern.compile(",\\s*}$");
   private static final ImmutableSet<BiFunction<AnnotationTree, VisitorState, Optional<Fix>>>
       FIX_FACTORIES =
           ImmutableSet.of(
-              CanonicalAnnotationSyntaxCheck::dropRedundantParentheses,
-              CanonicalAnnotationSyntaxCheck::dropRedundantValueAttribute,
-              CanonicalAnnotationSyntaxCheck::dropRedundantCurlies);
+              CanonicalAnnotationSyntax::dropRedundantParentheses,
+              CanonicalAnnotationSyntax::dropRedundantValueAttribute,
+              CanonicalAnnotationSyntax::dropRedundantCurlies);
 
   @Override
   public Description matchAnnotation(AnnotationTree tree, VisitorState state) {
@@ -103,7 +102,8 @@ public final class CanonicalAnnotationSyntaxCheck extends BugChecker
     return Optional.of(
         SuggestedFix.replace(
             arg,
-            simplifyAttributeValue(expr, state).orElseGet(() -> Util.treeToString(expr, state))));
+            simplifyAttributeValue(expr, state)
+                .orElseGet(() -> SourceCode.treeToString(expr, state))));
   }
 
   private static Optional<Fix> dropRedundantCurlies(AnnotationTree tree, VisitorState state) {
@@ -138,11 +138,11 @@ public final class CanonicalAnnotationSyntaxCheck extends BugChecker
   private static Optional<String> simplifySingletonArray(NewArrayTree array, VisitorState state) {
     return Optional.of(array.getInitializers())
         .filter(initializers -> initializers.size() == 1)
-        .map(initializers -> Util.treeToString(initializers.get(0), state));
+        .map(initializers -> SourceCode.treeToString(initializers.get(0), state));
   }
 
   private static Optional<String> dropTrailingComma(NewArrayTree array, VisitorState state) {
-    String src = Util.treeToString(array, state);
+    String src = SourceCode.treeToString(array, state);
     return Optional.of(TRAILING_ARRAY_COMMA.matcher(src))
         .filter(Matcher::find)
         .map(m -> src.substring(0, m.start()) + '}');

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

@@ -0,0 +1,117 @@
+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.FRAGILE_CODE;
+import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import java.util.stream.Collector;
+
+/**
+ * A {@link BugChecker} which flags {@link Collector Collectors} that don't clearly express
+ * (im)mutability.
+ *
+ * <p>Replacing such collectors with alternatives that produce immutable collections is preferred.
+ * Do note that Guava's immutable collections are null-hostile.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary =
+        "Avoid `Collectors.to{List,Map,Set}` in favour of alternatives that emphasize (im)mutability",
+    linkType = NONE,
+    severity = WARNING,
+    tags = FRAGILE_CODE)
+public final class CollectorMutability extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> COLLECTOR_METHOD =
+      staticMethod().onClass("java.util.stream.Collectors");
+  private static final Matcher<ExpressionTree> LIST_COLLECTOR =
+      staticMethod().anyClass().named("toList");
+  private static final Matcher<ExpressionTree> MAP_COLLECTOR =
+      staticMethod().anyClass().named("toMap");
+  private static final Matcher<ExpressionTree> SET_COLLECTOR =
+      staticMethod().anyClass().named("toSet");
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!COLLECTOR_METHOD.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    if (LIST_COLLECTOR.matches(tree, state)) {
+      return suggestToCollectionAlternatives(
+          tree, "com.google.common.collect.ImmutableList.toImmutableList", "ArrayList", state);
+    }
+
+    if (MAP_COLLECTOR.matches(tree, state)) {
+      return suggestToMapAlternatives(tree, state);
+    }
+
+    if (SET_COLLECTOR.matches(tree, state)) {
+      return suggestToCollectionAlternatives(
+          tree, "com.google.common.collect.ImmutableSet.toImmutableSet", "HashSet", state);
+    }
+
+    return Description.NO_MATCH;
+  }
+
+  private Description suggestToCollectionAlternatives(
+      MethodInvocationTree tree,
+      String fullyQualifiedImmutableReplacement,
+      String mutableReplacement,
+      VisitorState state) {
+    SuggestedFix.Builder mutableFix = SuggestedFix.builder();
+    String toCollectionSelect =
+        SuggestedFixes.qualifyStaticImport(
+            "java.util.stream.Collectors.toCollection", mutableFix, state);
+
+    return buildDescription(tree)
+        .addFix(replaceMethodInvocation(tree, fullyQualifiedImmutableReplacement, state))
+        .addFix(
+            mutableFix
+                .addImport(String.format("java.util.%s", mutableReplacement))
+                .replace(tree, String.format("%s(%s::new)", toCollectionSelect, mutableReplacement))
+                .build())
+        .build();
+  }
+
+  private Description suggestToMapAlternatives(MethodInvocationTree tree, VisitorState state) {
+    int argCount = tree.getArguments().size();
+    if (argCount > 3) {
+      return Description.NO_MATCH;
+    }
+
+    return buildDescription(tree)
+        .addFix(
+            replaceMethodInvocation(
+                tree, "com.google.common.collect.ImmutableMap.toImmutableMap", state))
+        .addFix(
+            SuggestedFix.builder()
+                .addImport("java.util.HashMap")
+                .postfixWith(
+                    tree.getArguments().get(argCount - 1),
+                    (argCount == 2 ? ", (a, b) -> { throw new IllegalStateException(); }" : "")
+                        + ", HashMap::new")
+                .build())
+        .build();
+  }
+
+  private static SuggestedFix replaceMethodInvocation(
+      MethodInvocationTree tree, String fullyQualifiedReplacement, VisitorState state) {
+    SuggestedFix.Builder fix = SuggestedFix.builder();
+    String replacement = SuggestedFixes.qualifyStaticImport(fullyQualifiedReplacement, fix, state);
+    fix.merge(SuggestedFix.replace(tree.getMethodSelect(), replacement));
+    return fix.build();
+  }
+}

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

@@ -20,18 +20,16 @@ import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.ClassTree;
 import com.sun.source.tree.MethodTree;
 import com.sun.source.tree.Tree;
-import com.sun.tools.javac.code.Symbol.MethodSymbol;
 import java.util.Optional;
 
 /** A {@link BugChecker} which flags empty methods that seemingly can simply be deleted. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "EmptyMethod",
     summary = "Empty method can likely be deleted",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class EmptyMethodCheck extends BugChecker implements MethodTreeMatcher {
+public final class EmptyMethod extends BugChecker implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<Tree> PERMITTED_ANNOTATION =
       annotations(
@@ -48,8 +46,7 @@ public final class EmptyMethodCheck extends BugChecker implements MethodTreeMatc
       return Description.NO_MATCH;
     }
 
-    MethodSymbol sym = ASTHelpers.getSymbol(tree);
-    if (sym == null || ASTHelpers.methodCanBeOverridden(sym)) {
+    if (ASTHelpers.methodCanBeOverridden(ASTHelpers.getSymbol(tree))) {
       return Description.NO_MATCH;
     }
 

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

@@ -0,0 +1,160 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
+import static com.google.errorprone.BugPattern.StandardTags.STYLE;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+import static java.util.stream.Collectors.joining;
+
+import com.google.auto.service.AutoService;
+import com.google.common.base.Splitter;
+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.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.google.googlejavaformat.java.Formatter;
+import com.google.googlejavaformat.java.FormatterException;
+import com.google.googlejavaformat.java.ImportOrderer;
+import com.google.googlejavaformat.java.JavaFormatterOptions.Style;
+import com.google.googlejavaformat.java.RemoveUnusedImports;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.Tree;
+import com.sun.tools.javac.util.Position;
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * A {@link BugChecker} which flags improperly formatted Error Prone test code.
+ *
+ * <p>All test code should be formatted in accordance with Google Java Format's {@link Formatter}
+ * output, and imports should be ordered according to the {@link Style#GOOGLE Google} style.
+ *
+ * <p>This checker inspects inline code passed to {@code
+ * com.google.errorprone.CompilationTestHelper} and {@code
+ * com.google.errorprone.BugCheckerRefactoringTestHelper}. It requires that this code is properly
+ * formatted and that its imports are organized. Only code that represents the expected output of a
+ * refactoring operation is allowed to have unused imports, as most {@link BugChecker}s do not (and
+ * are not able to) remove imports that become obsolete as a result of applying their suggested
+ * fix(es).
+ */
+// XXX: Once we target JDK 17 (optionally?) suggest text block fixes.
+// XXX: GJF guesses the line separator to be used by inspecting the source. When using text blocks
+// this may cause the current unconditional use of `\n` not to be sufficient when building on
+// Windows; TBD.
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Test code should follow the Google Java style",
+    linkType = NONE,
+    severity = SUGGESTION,
+    tags = STYLE)
+public final class ErrorProneTestHelperSourceFormat extends BugChecker
+    implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Formatter FORMATTER = new Formatter();
+  private static final Matcher<ExpressionTree> INPUT_SOURCE_ACCEPTING_METHOD =
+      anyOf(
+          instanceMethod()
+              .onDescendantOf("com.google.errorprone.CompilationTestHelper")
+              .named("addSourceLines"),
+          instanceMethod()
+              .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper")
+              .named("addInputLines"));
+  private static final Matcher<ExpressionTree> OUTPUT_SOURCE_ACCEPTING_METHOD =
+      instanceMethod()
+          .onDescendantOf("com.google.errorprone.BugCheckerRefactoringTestHelper.ExpectOutput")
+          .named("addOutputLines");
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    boolean isOutputSource = OUTPUT_SOURCE_ACCEPTING_METHOD.matches(tree, state);
+    if (!isOutputSource && !INPUT_SOURCE_ACCEPTING_METHOD.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    List<? extends ExpressionTree> sourceLines =
+        tree.getArguments().subList(1, tree.getArguments().size());
+    if (sourceLines.isEmpty()) {
+      return buildDescription(tree).setMessage("No source code provided").build();
+    }
+
+    int startPos = ASTHelpers.getStartPosition(sourceLines.get(0));
+    int endPos = state.getEndPosition(sourceLines.get(sourceLines.size() - 1));
+
+    /* Attempt to format the source code only if it fully consists of constant expressions. */
+    return getConstantSourceCode(sourceLines)
+        .map(source -> flagFormattingIssues(startPos, endPos, source, isOutputSource, state))
+        .orElse(Description.NO_MATCH);
+  }
+
+  private Description flagFormattingIssues(
+      int startPos, int endPos, String source, boolean retainUnusedImports, VisitorState state) {
+    Tree methodInvocation = state.getPath().getLeaf();
+
+    String formatted;
+    try {
+      formatted = formatSourceCode(source, retainUnusedImports).trim();
+    } catch (FormatterException e) {
+      return buildDescription(methodInvocation)
+          .setMessage(String.format("Source code is malformed: %s", e.getMessage()))
+          .build();
+    }
+
+    if (source.trim().equals(formatted)) {
+      return Description.NO_MATCH;
+    }
+
+    if (startPos == Position.NOPOS || endPos == Position.NOPOS) {
+      /*
+       * We have insufficient source information to emit a fix, so we only flag the fact that the
+       * code isn't properly formatted.
+       */
+      return describeMatch(methodInvocation);
+    }
+
+    /*
+     * The code isn't properly formatted; replace all lines with the properly formatted
+     * alternatives.
+     */
+    return describeMatch(
+        methodInvocation,
+        SuggestedFix.replace(
+            startPos,
+            endPos,
+            Splitter.on('\n')
+                .splitToStream(formatted)
+                .map(state::getConstantExpression)
+                .collect(joining(", "))));
+  }
+
+  private static String formatSourceCode(String source, boolean retainUnusedImports)
+      throws FormatterException {
+    String withReorderedImports = ImportOrderer.reorderImports(source, Style.GOOGLE);
+    String withOptionallyRemovedImports =
+        retainUnusedImports
+            ? withReorderedImports
+            : RemoveUnusedImports.removeUnusedImports(withReorderedImports);
+    return FORMATTER.formatSource(withOptionallyRemovedImports);
+  }
+
+  private static Optional<String> getConstantSourceCode(
+      List<? extends ExpressionTree> sourceLines) {
+    StringBuilder source = new StringBuilder();
+
+    for (ExpressionTree sourceLine : sourceLines) {
+      Object value = ASTHelpers.constValue(sourceLine);
+      if (value == null) {
+        return Optional.empty();
+      }
+
+      source.append(value).append('\n');
+    }
+
+    return Optional.of(source.toString());
+  }
+}

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

@@ -35,13 +35,11 @@ import java.util.stream.Stream;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "ExplicitEnumOrdering",
     summary = "Make sure `Ordering#explicit` lists all of an enum's values",
     linkType = NONE,
     severity = WARNING,
     tags = FRAGILE_CODE)
-public final class ExplicitEnumOrderingCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+public final class ExplicitEnumOrdering extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> EXPLICIT_ORDERING =
       staticMethod().onClass(Ordering.class.getName()).named("explicit");
@@ -73,7 +71,7 @@ public final class ExplicitEnumOrderingCheck extends BugChecker
         .collect(
             collectingAndThen(
                 toImmutableSetMultimap(Symbol::asType, Symbol::toString),
-                ExplicitEnumOrderingCheck::getMissingEnumValues));
+                ExplicitEnumOrdering::getMissingEnumValues));
   }
 
   private static ImmutableSet<String> getMissingEnumValues(

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

@@ -40,14 +40,13 @@ import reactor.core.publisher.Flux;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "FluxFlatMapUsage",
     summary =
         "`Flux#flatMap` and `Flux#flatMapSequential` have subtle semantics; "
             + "please use `Flux#concatMap` or explicitly specify the desired amount of concurrency",
     linkType = NONE,
     severity = ERROR,
     tags = LIKELY_ERROR)
-public final class FluxFlatMapUsageCheck extends BugChecker
+public final class FluxFlatMapUsage extends BugChecker
     implements MethodInvocationTreeMatcher, MemberReferenceTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String MAX_CONCURRENCY_ARG_NAME = "MAX_CONCURRENCY";

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

@@ -31,6 +31,8 @@ import com.sun.source.util.SimpleTreeVisitor;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
+import javax.annotation.Nullable;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags string concatenations that produce a format string; in such
@@ -48,12 +50,11 @@ import java.util.Optional;
 // invocations, as necessary.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "FormatStringConcatenation",
     summary = "Defer string concatenation to the invoked method",
     linkType = NONE,
     severity = WARNING,
     tags = SIMPLIFICATION)
-public final class FormatStringConcatenationCheck extends BugChecker
+public final class FormatStringConcatenation extends BugChecker
     implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   /**
@@ -210,6 +211,7 @@ public final class FormatStringConcatenationCheck extends BugChecker
       this.formatSpecifier = formatSpecifier;
     }
 
+    @Nullable
     @Override
     public Void visitBinary(BinaryTree tree, VisitorState state) {
       if (tree.getKind() == Kind.PLUS && isStringTyped(tree, state)) {
@@ -222,11 +224,13 @@ public final class FormatStringConcatenationCheck extends BugChecker
       return null;
     }
 
+    @Nullable
     @Override
     public Void visitParenthesized(ParenthesizedTree tree, VisitorState state) {
       return tree.getExpression().accept(this, state);
     }
 
+    @Nullable
     @Override
     protected Void defaultAction(Tree tree, VisitorState state) {
       appendExpression(tree);
@@ -246,7 +250,7 @@ public final class FormatStringConcatenationCheck extends BugChecker
       return state.getConstantExpression(formatString.toString())
           + ", "
           + formatArguments.stream()
-              .map(tree -> Util.treeToString(tree, state))
+              .map(tree -> SourceCode.treeToString(tree, state))
               .collect(joining(", "));
     }
   }

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

@@ -27,6 +27,7 @@ import com.sun.tools.javac.code.Type;
 import com.sun.tools.javac.code.Types;
 import java.util.Arrays;
 import java.util.List;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} that flags redundant identity conversions. */
 // XXX: Consider detecting cases where a flagged expression is passed to a method, and where removal
@@ -34,13 +35,11 @@ import java.util.List;
 // the target method such a modification may change the code's semantics or performance.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "IdentityConversion",
     summary = "Avoid or clarify identity conversions",
     linkType = NONE,
     severity = WARNING,
     tags = SIMPLIFICATION)
-public final class IdentityConversionCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+public final class IdentityConversion extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> IS_CONVERSION_METHOD =
       anyOf(
@@ -95,7 +94,7 @@ public final class IdentityConversionCheck extends BugChecker
         .setMessage(
             "This method invocation appears redundant; remove it or suppress this warning and "
                 + "add a comment explaining its purpose")
-        .addFix(SuggestedFix.replace(tree, Util.treeToString(sourceTree, state)))
+        .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

@@ -0,0 +1,81 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugPattern.LinkType.NONE;
+import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
+import static com.google.errorprone.BugPattern.StandardTags.LIKELY_ERROR;
+import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.enclosingClass;
+import static com.google.errorprone.matchers.Matchers.hasAnnotation;
+import static com.google.errorprone.matchers.Matchers.hasModifier;
+import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
+import static com.google.errorprone.matchers.Matchers.methodReturns;
+import static com.google.errorprone.matchers.Matchers.not;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.fixes.SuggestedFixes;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.sun.source.tree.MethodTree;
+import java.util.SortedSet;
+import javax.lang.model.element.Modifier;
+
+/**
+ * A {@link BugChecker} which flags {@link SortedSet} property declarations inside
+ * {@code @Value.Immutable}- and {@code @Value.Modifiable}-annotated types that lack a
+ * {@code @Value.NaturalOrder} or {@code @Value.ReverseOrder} annotation.
+ *
+ * <p>Without such an annotation:
+ *
+ * <ul>
+ *   <li>deserialization of the enclosing type requires that the associated JSON property is
+ *       present, contrary to the way in which Immutables handles other collection properties; and
+ *   <li>different instances may use different comparator implementations (e.g. deserialization
+ *       would default to natural order sorting), potentially leading to subtle bugs.
+ * </ul>
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary =
+        "`SortedSet` properties of a `@Value.Immutable` or `@Value.Modifiable` type must be "
+            + "annotated with `@Value.NaturalOrder` or `@Value.ReverseOrder`",
+    linkType = NONE,
+    severity = ERROR,
+    tags = LIKELY_ERROR)
+public final class ImmutablesSortedSetComparator extends BugChecker implements MethodTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<MethodTree> METHOD_LACKS_ANNOTATION =
+      allOf(
+          methodReturns(isSubtypeOf(SortedSet.class)),
+          anyOf(
+              allOf(
+                  hasModifier(Modifier.ABSTRACT),
+                  enclosingClass(
+                      anyOf(
+                          hasAnnotation("org.immutables.value.Value.Immutable"),
+                          hasAnnotation("org.immutables.value.Value.Modifiable")))),
+              hasAnnotation("org.immutables.value.Value.Default")),
+          not(
+              anyOf(
+                  hasAnnotation("org.immutables.value.Value.NaturalOrder"),
+                  hasAnnotation("org.immutables.value.Value.ReverseOrder"))));
+
+  @Override
+  public Description matchMethod(MethodTree tree, VisitorState state) {
+    if (!METHOD_LACKS_ANNOTATION.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    SuggestedFix.Builder builder = SuggestedFix.builder();
+    String valueTypeIdentifier =
+        SuggestedFixes.qualifyType(state, builder, "org.immutables.value.Value");
+    return describeMatch(
+        tree,
+        builder.prefixWith(tree, String.format("@%s.NaturalOrder ", valueTypeIdentifier)).build());
+  }
+}

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

@@ -11,7 +11,7 @@ import static com.google.errorprone.matchers.Matchers.enclosingClass;
 import static com.google.errorprone.matchers.Matchers.hasModifier;
 import static com.google.errorprone.matchers.Matchers.isType;
 import static java.util.function.Predicate.not;
-import static tech.picnic.errorprone.bugpatterns.JavaKeywords.isReservedKeyword;
+import static tech.picnic.errorprone.bugpatterns.util.JavaKeywords.isReservedKeyword;
 
 import com.google.auto.service.AutoService;
 import com.google.common.collect.ImmutableSet;
@@ -36,21 +36,21 @@ import com.sun.tools.javac.code.Symbol;
 import java.util.Optional;
 import javax.lang.model.element.Modifier;
 import javax.lang.model.element.Name;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} which flags non-canonical JUnit method declarations. */
 // XXX: Consider introducing a class-level check which enforces that test classes:
 // 1. Are named `*Test` or `Abstract*TestCase`.
-// 2. If not `abstract`, don't have public methods and subclasses.
+// 2. If not `abstract`, are package-private and don't have public methods and subclasses.
 // 3. Only have private fields.
 // XXX: If implemented, the current logic could flag only `private` JUnit methods.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "JUnitMethodDeclaration",
     summary = "JUnit method declaration can likely be improved",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class JUnitMethodDeclarationCheck extends BugChecker implements MethodTreeMatcher {
+public final class JUnitMethodDeclaration extends BugChecker implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String TEST_PREFIX = "test";
   private static final ImmutableSet<Modifier> ILLEGAL_MODIFIERS =
@@ -171,13 +171,12 @@ public final class JUnitMethodDeclarationCheck extends BugChecker implements Met
   }
 
   private static CharSequence getStaticImportSimpleName(Tree tree, VisitorState state) {
-    String source = Util.treeToString(tree, state);
+    String source = SourceCode.treeToString(tree, state);
     return source.subSequence(source.lastIndexOf('.') + 1, source.length());
   }
 
   private static Optional<String> tryCanonicalizeMethodName(MethodTree tree) {
-    return Optional.ofNullable(ASTHelpers.getSymbol(tree))
-        .map(sym -> sym.getQualifiedName().toString())
+    return Optional.of(ASTHelpers.getSymbol(tree).getQualifiedName().toString())
         .filter(name -> name.startsWith(TEST_PREFIX))
         .map(name -> name.substring(TEST_PREFIX.length()))
         .filter(not(String::isEmpty))

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

@@ -37,6 +37,9 @@ import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Stream;
+import javax.annotation.Nullable;
+import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags annotation array listings which aren't sorted lexicographically.
@@ -46,12 +49,11 @@ import java.util.stream.Stream;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "LexicographicalAnnotationAttributeListing",
     summary = "Where possible, sort annotation array attributes lexicographically",
     linkType = NONE,
     severity = SUGGESTION,
     tags = STYLE)
-public final class LexicographicalAnnotationAttributeListingCheck extends BugChecker
+public final class LexicographicalAnnotationAttributeListing extends BugChecker
     implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final ImmutableSet<String> BLACKLISTED_ANNOTATIONS =
@@ -60,24 +62,27 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
           "com.fasterxml.jackson.annotation.JsonPropertyOrder#value",
           "io.swagger.annotations.ApiImplicitParams#value",
           "io.swagger.v3.oas.annotations.Parameters#value",
-          "javax.xml.bind.annotation.XmlType#propOrder");
+          "javax.xml.bind.annotation.XmlType#propOrder",
+          "org.springframework.context.annotation.PropertySource#value",
+          "org.springframework.test.context.TestPropertySource#locations",
+          "org.springframework.test.context.TestPropertySource#value");
   private static final String FLAG_PREFIX = "LexicographicalAnnotationAttributeListing:";
   private static final String INCLUDED_ANNOTATIONS_FLAG = FLAG_PREFIX + "Includes";
   private static final String EXCLUDED_ANNOTATIONS_FLAG = FLAG_PREFIX + "Excludes";
 
   private final AnnotationAttributeMatcher matcher;
 
-  /** Instantiates the default {@link LexicographicalAnnotationAttributeListingCheck}. */
-  public LexicographicalAnnotationAttributeListingCheck() {
+  /** Instantiates the default {@link LexicographicalAnnotationAttributeListing}. */
+  public LexicographicalAnnotationAttributeListing() {
     this(ErrorProneFlags.empty());
   }
 
   /**
-   * Instantiates a customized {@link LexicographicalAnnotationAttributeListingCheck}.
+   * Instantiates a customized {@link LexicographicalAnnotationAttributeListing}.
    *
    * @param flags Any provided command line flags.
    */
-  public LexicographicalAnnotationAttributeListingCheck(ErrorProneFlags flags) {
+  public LexicographicalAnnotationAttributeListing(ErrorProneFlags flags) {
     matcher = createAnnotationAttributeMatcher(flags);
   }
 
@@ -128,7 +133,7 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
     /* The elements aren't sorted. Suggest the sorted alternative. */
     String suggestion =
         desiredOrdering.stream()
-            .map(expr -> Util.treeToString(expr, state))
+            .map(expr -> SourceCode.treeToString(expr, state))
             .collect(joining(", ", "{", "}"));
     return Optional.of(SuggestedFix.builder().replace(array, suggestion));
   }
@@ -171,20 +176,23 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
     ImmutableList.Builder<ImmutableList<String>> nodes = ImmutableList.builder();
 
     new TreeScanner<Void, Void>() {
+      @Nullable
       @Override
-      public Void visitIdentifier(IdentifierTree node, Void ctx) {
+      public Void visitIdentifier(IdentifierTree node, @Nullable Void ctx) {
         nodes.add(tokenize(node));
         return super.visitIdentifier(node, ctx);
       }
 
+      @Nullable
       @Override
-      public Void visitLiteral(LiteralTree node, Void ctx) {
+      public Void visitLiteral(LiteralTree node, @Nullable Void ctx) {
         nodes.add(tokenize(node));
         return super.visitLiteral(node, ctx);
       }
 
+      @Nullable
       @Override
-      public Void visitPrimitiveType(PrimitiveTypeTree node, Void ctx) {
+      public Void visitPrimitiveType(PrimitiveTypeTree node, @Nullable Void ctx) {
         nodes.add(tokenize(node));
         return super.visitPrimitiveType(node, ctx);
       }
@@ -194,7 +202,7 @@ public final class LexicographicalAnnotationAttributeListingCheck extends BugChe
          * Tokens are split on `=` so that e.g. inline Spring property declarations are properly
          * sorted by key, then value.
          */
-        return ImmutableList.copyOf(Util.treeToString(node, state).split("=", -1));
+        return ImmutableList.copyOf(SourceCode.treeToString(node, state).split("=", -1));
       }
     }.scan(array, null);
 

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

@@ -20,6 +20,7 @@ import com.sun.source.tree.AnnotationTree;
 import com.sun.source.tree.MethodTree;
 import java.util.List;
 import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} that flags annotations that are not lexicographically sorted.
@@ -29,12 +30,11 @@ import java.util.Optional;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "LexicographicalAnnotationListing",
     summary = "Sort annotations lexicographically where possible",
     linkType = NONE,
     severity = SUGGESTION,
     tags = STYLE)
-public final class LexicographicalAnnotationListingCheck extends BugChecker
+public final class LexicographicalAnnotationListing extends BugChecker
     implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
 
@@ -52,7 +52,7 @@ public final class LexicographicalAnnotationListingCheck extends BugChecker
 
     Optional<Fix> fix = tryFixOrdering(originalOrdering, sortedAnnotations, state);
 
-    Description.Builder description = buildDescription(tree);
+    Description.Builder description = buildDescription(originalOrdering.get(0));
     fix.ifPresent(description::addFix);
     return description.build();
   }
@@ -60,7 +60,7 @@ public final class LexicographicalAnnotationListingCheck extends BugChecker
   private static ImmutableList<? extends AnnotationTree> sort(
       List<? extends AnnotationTree> annotations, VisitorState state) {
     return annotations.stream()
-        .sorted(comparing(annotation -> Util.treeToString(annotation, state)))
+        .sorted(comparing(annotation -> SourceCode.treeToString(annotation, state)))
         .collect(toImmutableList());
   }
 
@@ -72,7 +72,8 @@ public final class LexicographicalAnnotationListingCheck extends BugChecker
             originalAnnotations.stream(),
             sortedAnnotations.stream(),
             (original, replacement) ->
-                SuggestedFix.builder().replace(original, Util.treeToString(replacement, state)))
+                SuggestedFix.builder()
+                    .replace(original, SourceCode.treeToString(replacement, state)))
         .reduce(SuggestedFix.Builder::merge)
         .map(SuggestedFix.Builder::build);
   }

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

@@ -51,13 +51,11 @@ import javax.lang.model.element.Name;
 // Palantir's `LambdaMethodReference` check seems to suffer a similar issue at this time.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "MethodReferenceUsage",
     summary = "Prefer method references over lambda expressions",
     linkType = NONE,
     severity = SUGGESTION,
     tags = STYLE)
-public final class MethodReferenceUsageCheck extends BugChecker
-    implements LambdaExpressionTreeMatcher {
+public final class MethodReferenceUsage extends BugChecker implements LambdaExpressionTreeMatcher {
   private static final long serialVersionUID = 1L;
 
   @Override
@@ -102,6 +100,8 @@ public final class MethodReferenceUsageCheck extends BugChecker
         .flatMap(statements -> constructMethodRef(lambdaExpr, statements.get(0)));
   }
 
+  // XXX: Replace nested `Optional` usage.
+  @SuppressWarnings("NestedOptionals")
   private static Optional<SuggestedFix.Builder> constructMethodRef(
       LambdaExpressionTree lambdaExpr, MethodInvocationTree subTree) {
     return matchArguments(lambdaExpr, subTree)
@@ -158,6 +158,8 @@ public final class MethodReferenceUsageCheck extends BugChecker
     return constructFix(lambdaExpr, lhsType.tsym, subTree.getIdentifier());
   }
 
+  // XXX: Refactor or replace inner `Optional` with a custom type.
+  @SuppressWarnings("NestedOptionals")
   private static Optional<Optional<Name>> matchArguments(
       LambdaExpressionTree lambdaExpr, MethodInvocationTree subTree) {
     ImmutableList<Name> expectedArguments = getVariables(lambdaExpr);

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

@@ -24,12 +24,11 @@ import com.sun.source.tree.Tree;
 /** A {@link BugChecker} that flags likely missing Refaster annotations. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "MissingRefasterAnnotation",
     summary = "The Refaster template contains a method without any Refaster annotations",
     linkType = NONE,
     severity = WARNING,
     tags = LIKELY_ERROR)
-public final class MissingRefasterAnnotationCheck extends BugChecker implements ClassTreeMatcher {
+public final class MissingRefasterAnnotation extends BugChecker implements ClassTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final MultiMatcher<Tree, AnnotationTree> REFASTER_ANNOTATION =
       annotations(

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

@@ -17,6 +17,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
 import java.util.List;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags method invocations for which all arguments are wrapped using
@@ -24,12 +25,11 @@ import java.util.List;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "MockitoStubbing",
     summary = "Don't unnecessarily use Mockito's `eq(...)`",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class MockitoStubbingCheck extends BugChecker implements MethodInvocationTreeMatcher {
+public final class MockitoStubbing extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> MOCKITO_EQ_METHOD =
       staticMethod().onClass("org.mockito.ArgumentMatchers").named("eq");
@@ -45,7 +45,7 @@ public final class MockitoStubbingCheck extends BugChecker implements MethodInvo
     for (ExpressionTree arg : arguments) {
       suggestedFix.replace(
           arg,
-          Util.treeToString(
+          SourceCode.treeToString(
               Iterables.getOnlyElement(((MethodInvocationTree) arg).getArguments()), state));
     }
 

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

@@ -0,0 +1,51 @@
+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.FRAGILE_CODE;
+
+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.matchers.Description;
+import com.google.errorprone.suppliers.Supplier;
+import com.google.errorprone.suppliers.Suppliers;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.MethodInvocationTree;
+import com.sun.source.tree.Tree;
+import com.sun.tools.javac.code.Type;
+import com.sun.tools.javac.util.List;
+import java.util.Optional;
+
+/** A {@link BugChecker} which flags nesting of {@link Optional Optionals}. */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary =
+        "Avoid nesting `Optional`s inside `Optional`s; the resultant code is hard to reason about",
+    linkType = NONE,
+    severity = WARNING,
+    tags = FRAGILE_CODE)
+public final class NestedOptionals extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Supplier<Type> OPTIONAL = Suppliers.typeFromClass(Optional.class);
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    return isOptionalOfOptional(tree, state) ? describeMatch(tree) : Description.NO_MATCH;
+  }
+
+  private static boolean isOptionalOfOptional(Tree tree, VisitorState state) {
+    Type optionalType = OPTIONAL.get(state);
+    Type type = ASTHelpers.getType(tree);
+    if (!ASTHelpers.isSubtype(type, optionalType, state)) {
+      return false;
+    }
+
+    List<Type> typeArguments = type.getTypeArguments();
+    return !typeArguments.isEmpty()
+        && ASTHelpers.isSubtype(Iterables.getOnlyElement(typeArguments), optionalType, state);
+  }
+}

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

@@ -0,0 +1,91 @@
+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.SIMPLIFICATION;
+import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.instanceMethod;
+
+import com.google.auto.service.AutoService;
+import com.google.errorprone.BugPattern;
+import com.google.errorprone.VisitorState;
+import com.google.errorprone.bugpatterns.BugChecker;
+import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
+import com.google.errorprone.fixes.SuggestedFix;
+import com.google.errorprone.matchers.Description;
+import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.util.ASTHelpers;
+import com.sun.source.tree.ExpressionTree;
+import com.sun.source.tree.MethodInvocationTree;
+import java.util.function.BiFunction;
+import reactor.core.publisher.Mono;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
+
+/**
+ * A {@link BugChecker} which flags {@link Mono} operations that are known to be vacuous, given that
+ * they are invoked on a {@link Mono} that is known not to complete empty.
+ */
+@AutoService(BugChecker.class)
+@BugPattern(
+    summary = "Avoid vacuous operations on known non-empty `Mono`s",
+    linkType = NONE,
+    severity = WARNING,
+    tags = SIMPLIFICATION)
+// XXX: This check does not simplify `someFlux.defaultIfEmpty(T).{defaultIfEmpty(T),hasElements()}`,
+// as `someFlux.defaultIfEmpty(T)` yields a `Flux` rather than a `Mono`. Consider adding support for
+// these cases.
+// XXX: Given more advanced analysis many more expressions could be flagged. Consider
+// `Mono.just(someValue)`, `Flux.just(someNonEmptySequence)`,
+// `someMono.switchIfEmpty(someProvablyNonEmptyMono)` and many other variants.
+// XXX: Consider implementing a similar check for `Publisher`s that are known to complete without
+// emitting a value (e.g. `Mono.empty()`, `someFlux.then()`, ...), or known not to complete normally
+// (`Mono.never()`, `someFlux.repeat()`, `Mono.error(...)`, ...). The latter category could
+// potentially be split out further.
+public final class NonEmptyMono extends BugChecker implements MethodInvocationTreeMatcher {
+  private static final long serialVersionUID = 1L;
+  private static final Matcher<ExpressionTree> MONO_SIZE_CHECK =
+      instanceMethod()
+          .onDescendantOf("reactor.core.publisher.Mono")
+          .namedAnyOf("defaultIfEmpty", "single", "switchIfEmpty");
+  private static final Matcher<ExpressionTree> NON_EMPTY_MONO =
+      anyOf(
+          instanceMethod()
+              .onDescendantOf("reactor.core.publisher.Flux")
+              .namedAnyOf(
+                  "all",
+                  "any",
+                  "collect",
+                  "collectList",
+                  "collectMap",
+                  "collectMultimap",
+                  "collectSortedList",
+                  "count",
+                  "elementAt",
+                  "hasElement",
+                  "hasElements",
+                  "last",
+                  "reduceWith",
+                  "single"),
+          instanceMethod()
+              .onDescendantOf("reactor.core.publisher.Flux")
+              .named("reduce")
+              .withParameters(Object.class.getName(), BiFunction.class.getName()),
+          instanceMethod()
+              .onDescendantOf("reactor.core.publisher.Mono")
+              .namedAnyOf("defaultIfEmpty", "hasElement", "single"));
+
+  @Override
+  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
+    if (!MONO_SIZE_CHECK.matches(tree, state)) {
+      return Description.NO_MATCH;
+    }
+
+    ExpressionTree receiver = ASTHelpers.getReceiver(tree);
+    if (!NON_EMPTY_MONO.matches(receiver, state)) {
+      return Description.NO_MATCH;
+    }
+
+    return describeMatch(
+        tree, SuggestedFix.replace(tree, SourceCode.treeToString(receiver, state)));
+  }
+}

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

@@ -6,7 +6,6 @@ import static com.google.errorprone.BugPattern.StandardTags.PERFORMANCE;
 import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
-import static java.util.function.Predicate.not;
 import static java.util.stream.Collectors.joining;
 
 import com.google.auto.service.AutoService;
@@ -32,6 +31,7 @@ import java.util.Comparator;
 import java.util.Optional;
 import java.util.function.Function;
 import java.util.stream.Stream;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags {@code Comparator#comparing*} invocations that can be replaced
@@ -41,15 +41,13 @@ import java.util.stream.Stream;
 // specific types.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "PrimitiveComparison",
     summary =
         "Ensure invocations of `Comparator#comparing{,Double,Int,Long}` match the return type"
             + " of the provided function",
     linkType = NONE,
     severity = WARNING,
     tags = PERFORMANCE)
-public final class PrimitiveComparisonCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+public final class PrimitiveComparison extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> STATIC_COMPARISON_METHOD =
       anyOf(
@@ -85,16 +83,15 @@ public final class PrimitiveComparisonCheck extends BugChecker
 
   private static Optional<Fix> attemptMethodInvocationReplacement(
       MethodInvocationTree tree, Type cmpType, boolean isStatic, VisitorState state) {
-    return Optional.ofNullable(ASTHelpers.getSymbol(tree))
-        .map(methodSymbol -> methodSymbol.getSimpleName().toString())
-        .flatMap(
-            actualMethodName ->
-                Optional.of(getPreferredMethod(cmpType, isStatic, state))
-                    .filter(not(actualMethodName::equals)))
-        .map(
-            preferredMethodName ->
-                prefixTypeArgumentsIfRelevant(preferredMethodName, tree, cmpType, state))
-        .map(preferredMethodName -> suggestFix(tree, preferredMethodName, state));
+    String actualMethodName = ASTHelpers.getSymbol(tree).getSimpleName().toString();
+    String preferredMethodName = getPreferredMethod(cmpType, isStatic, state);
+    if (actualMethodName.equals(preferredMethodName)) {
+      return Optional.empty();
+    }
+
+    return Optional.of(
+        suggestFix(
+            tree, prefixTypeArgumentsIfRelevant(preferredMethodName, tree, cmpType, state), state));
   }
 
   /**
@@ -116,7 +113,7 @@ public final class PrimitiveComparisonCheck extends BugChecker
 
     String typeArguments =
         Stream.concat(
-                Stream.of(Util.treeToString(tree.getTypeArguments().get(0), state)),
+                Stream.of(SourceCode.treeToString(tree.getTypeArguments().get(0), state)),
                 Stream.of(cmpType.tsym.getSimpleName())
                     .filter(u -> "comparing".equals(preferredMethodName)))
             .collect(joining(", ", "<", ">"));
@@ -171,7 +168,7 @@ public final class PrimitiveComparisonCheck extends BugChecker
       case MEMBER_SELECT:
         MemberSelectTree ms = (MemberSelectTree) tree.getMethodSelect();
         return SuggestedFix.replace(
-            ms, Util.treeToString(ms.getExpression(), state) + '.' + preferredMethodName);
+            ms, SourceCode.treeToString(ms.getExpression(), state) + '.' + preferredMethodName);
       default:
         throw new VerifyException("Unexpected type of expression: " + expr.getKind());
     }

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

@@ -1,10 +1,13 @@
 package tech.picnic.errorprone.bugpatterns;
 
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.errorprone.BugPattern.LinkType.NONE;
 import static com.google.errorprone.BugPattern.SeverityLevel.SUGGESTION;
 import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static com.google.errorprone.matchers.Matchers.allOf;
+import static com.google.errorprone.matchers.Matchers.anyMethod;
 import static com.google.errorprone.matchers.Matchers.anyOf;
+import static com.google.errorprone.matchers.Matchers.argumentCount;
 import static com.google.errorprone.matchers.Matchers.isNonNullUsingDataflow;
 import static com.google.errorprone.matchers.Matchers.isSameType;
 import static com.google.errorprone.matchers.Matchers.isSubtypeOf;
@@ -13,7 +16,9 @@ import static com.google.errorprone.matchers.method.MethodMatchers.instanceMetho
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 
 import com.google.auto.service.AutoService;
+import com.google.common.collect.ImmutableList;
 import com.google.common.collect.Iterables;
+import com.google.common.primitives.Primitives;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.ErrorProneFlags;
 import com.google.errorprone.VisitorState;
@@ -24,6 +29,7 @@ import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
 import com.google.errorprone.fixes.SuggestedFix;
 import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
+import com.google.errorprone.suppliers.Suppliers;
 import com.sun.source.tree.BinaryTree;
 import com.sun.source.tree.CompoundAssignmentTree;
 import com.sun.source.tree.ExpressionTree;
@@ -41,16 +47,18 @@ import java.util.List;
 import java.util.Locale;
 import java.util.Objects;
 import java.util.Optional;
+import java.util.stream.Stream;
+import tech.picnic.errorprone.bugpatterns.util.MethodMatcherFactory;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} which flags redundant explicit string conversions. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "RedundantStringConversion",
     summary = "Avoid redundant string conversions when possible",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class RedundantStringConversionCheck extends BugChecker
+public final class RedundantStringConversion extends BugChecker
     implements BinaryTreeMatcher, CompoundAssignmentTreeMatcher, MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String FLAG_PREFIX = "RedundantStringConversion:";
@@ -68,49 +76,30 @@ public final class RedundantStringConversionCheck extends BugChecker
       allOf(STRING, isNonNullUsingDataflow());
   private static final Matcher<ExpressionTree> NOT_FORMATTABLE =
       not(isSubtypeOf(Formattable.class));
-  private static final Matcher<ExpressionTree> WELL_KNOWN_STRING_CONVERSION_METHODS =
+  private static final Matcher<MethodInvocationTree> WELL_KNOWN_STRING_CONVERSION_METHODS =
       anyOf(
-          instanceMethod().onDescendantOfAny(Object.class.getName()).named("toString"),
-          staticMethod()
-              .onClass(Objects.class.getName())
+          instanceMethod()
+              .onDescendantOfAny(Object.class.getName())
               .named("toString")
-              .withParameters(Object.class.getName()),
-          staticMethod()
-              .onClass(String.class.getName())
-              .named("valueOf")
-              .withParameters(Object.class.getName()),
-          staticMethod()
-              .onClass(String.class.getName())
-              .named("valueOf")
-              .withParameters(String.class.getName()),
-          staticMethod()
-              .onClass(Byte.class.getName())
-              .named("toString")
-              .withParameters(byte.class.getName()),
-          staticMethod()
-              .onClass(Character.class.getName())
-              .named("toString")
-              .withParameters(char.class.getName()),
-          staticMethod()
-              .onClass(Short.class.getName())
-              .named("toString")
-              .withParameters(short.class.getName()),
-          staticMethod()
-              .onClass(Integer.class.getName())
-              .named("toString")
-              .withParameters(int.class.getName()),
-          staticMethod()
-              .onClass(Long.class.getName())
-              .named("toString")
-              .withParameters(long.class.getName()),
-          staticMethod()
-              .onClass(Float.class.getName())
-              .named("toString")
-              .withParameters(float.class.getName()),
-          staticMethod()
-              .onClass(Double.class.getName())
-              .named("toString")
-              .withParameters(double.class.getName()));
+              .withNoParameters(),
+          allOf(
+              argumentCount(1),
+              anyOf(
+                  staticMethod()
+                      .onClassAny(
+                          Stream.concat(
+                                  Primitives.allWrapperTypes().stream(), Stream.of(Objects.class))
+                              .map(Class::getName)
+                              .collect(toImmutableSet()))
+                      .named("toString"),
+                  allOf(
+                      staticMethod().onClass(String.class.getName()).named("valueOf"),
+                      not(
+                          anyMethod()
+                              .anyClass()
+                              .withAnyName()
+                              .withParametersOfType(
+                                  ImmutableList.of(Suppliers.arrayOf(Suppliers.CHAR_TYPE))))))));
   private static final Matcher<ExpressionTree> STRINGBUILDER_APPEND_INVOCATION =
       instanceMethod()
           .onDescendantOf(StringBuilder.class.getName())
@@ -126,17 +115,10 @@ public final class RedundantStringConversionCheck extends BugChecker
           staticMethod().onClass(String.class.getName()).named("format"),
           instanceMethod().onDescendantOf(Formatter.class.getName()).named("format"),
           instanceMethod()
-              .onDescendantOf(PrintStream.class.getName())
+              .onDescendantOfAny(PrintStream.class.getName(), PrintWriter.class.getName())
               .namedAnyOf("format", "printf"),
           instanceMethod()
-              .onDescendantOf(PrintStream.class.getName())
-              .namedAnyOf("print", "println")
-              .withParameters(Object.class.getName()),
-          instanceMethod()
-              .onDescendantOf(PrintWriter.class.getName())
-              .namedAnyOf("format", "printf"),
-          instanceMethod()
-              .onDescendantOf(PrintWriter.class.getName())
+              .onDescendantOfAny(PrintStream.class.getName(), PrintWriter.class.getName())
               .namedAnyOf("print", "println")
               .withParameters(Object.class.getName()),
           staticMethod()
@@ -155,19 +137,19 @@ public final class RedundantStringConversionCheck extends BugChecker
           .onDescendantOf("org.slf4j.Logger")
           .namedAnyOf("trace", "debug", "info", "warn", "error");
 
-  private final Matcher<ExpressionTree> conversionMethodMatcher;
+  private final Matcher<MethodInvocationTree> conversionMethodMatcher;
 
-  /** Instantiates the default {@link RedundantStringConversionCheck}. */
-  public RedundantStringConversionCheck() {
+  /** Instantiates the default {@link RedundantStringConversion}. */
+  public RedundantStringConversion() {
     this(ErrorProneFlags.empty());
   }
 
   /**
-   * Instantiates a customized {@link RedundantStringConversionCheck}.
+   * Instantiates a customized {@link RedundantStringConversion}.
    *
    * @param flags Any provided command line flags.
    */
-  public RedundantStringConversionCheck(ErrorProneFlags flags) {
+  public RedundantStringConversion(ErrorProneFlags flags) {
     conversionMethodMatcher = createConversionMethodMatcher(flags);
   }
 
@@ -185,7 +167,7 @@ public final class RedundantStringConversionCheck extends BugChecker
 
     List<SuggestedFix.Builder> fixes = new ArrayList<>();
 
-    // XXX: Not so nice: we try to simplify the RHS twice.
+    // XXX: Avoid trying to simplify the RHS twice.
     ExpressionTree preferredRhs = trySimplify(rhs, state).orElse(rhs);
     if (STRING.matches(preferredRhs, state)) {
       tryFix(lhs, state, ANY_EXPR).ifPresent(fixes::add);
@@ -275,15 +257,15 @@ public final class RedundantStringConversionCheck extends BugChecker
 
   // XXX: Write another check which checks that SLF4J patterns don't use `%s` and have a matching
   // number of arguments of the appropriate type. Also flag explicit conversions from `Throwable` to
-  // string as the last logger argument. Suggests either dropping the converison or going with
+  // string as the last logger argument. Suggests either dropping the conversion or going with
   // `Throwable#getMessage()` instead.
   private Optional<SuggestedFix.Builder> tryFixSlf4jLogger(
       List<? extends ExpressionTree> arguments, VisitorState state) {
     /*
-     * SLF4J treats the final argument to a log statement specially if it is a `Throwabe`: it
+     * SLF4J treats the final argument to a log statement specially if it is a `Throwable`: it
      * will always choose to render the associated stacktrace, even if the argument has a
      * matching `{}` placeholder. (In this case the `{}` will simply be logged verbatim.) So if
-     * a log statement's final argument is the string representation of a `Throwble`, then we
+     * a log statement's final argument is the string representation of a `Throwable`, then we
      * must not strip this explicit string conversion, as that would change the statement's
      * semantics.
      */
@@ -326,7 +308,7 @@ public final class RedundantStringConversionCheck extends BugChecker
     return trySimplify(tree, state, filter)
         .map(
             replacement ->
-                SuggestedFix.builder().replace(tree, Util.treeToString(replacement, state)));
+                SuggestedFix.builder().replace(tree, SourceCode.treeToString(replacement, state)));
   }
 
   private Optional<ExpressionTree> trySimplify(
@@ -337,11 +319,15 @@ public final class RedundantStringConversionCheck extends BugChecker
   }
 
   private Optional<ExpressionTree> trySimplify(ExpressionTree tree, VisitorState state) {
-    if (tree.getKind() != Kind.METHOD_INVOCATION || !conversionMethodMatcher.matches(tree, state)) {
+    if (tree.getKind() != Kind.METHOD_INVOCATION) {
       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);
@@ -350,7 +336,7 @@ public final class RedundantStringConversionCheck extends BugChecker
       default:
         throw new IllegalStateException(
             "Cannot simplify method call with two or more arguments: "
-                + Util.treeToString(tree, state));
+                + SourceCode.treeToString(tree, state));
     }
   }
 
@@ -363,7 +349,7 @@ public final class RedundantStringConversionCheck extends BugChecker
     return Optional.of(methodInvocation.getMethodSelect())
         .filter(methodSelect -> methodSelect.getKind() == Kind.MEMBER_SELECT)
         .map(methodSelect -> ((MemberSelectTree) methodSelect).getExpression())
-        .filter(expr -> !"super".equals(Util.treeToString(expr, state)));
+        .filter(expr -> !"super".equals(SourceCode.treeToString(expr, state)));
   }
 
   private static Optional<ExpressionTree> trySimplifyUnaryMethod(
@@ -382,7 +368,8 @@ public final class RedundantStringConversionCheck extends BugChecker
         .orElse(Description.NO_MATCH);
   }
 
-  private static Matcher<ExpressionTree> createConversionMethodMatcher(ErrorProneFlags flags) {
+  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.
     return flags

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

@@ -16,6 +16,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.refaster.Refaster;
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags unnecessary {@link Refaster#anyOf(Object[])} usages.
@@ -25,13 +26,11 @@ import com.sun.source.tree.MethodInvocationTree;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "RefasterAnyOfUsage",
     summary = "`Refaster#anyOf` should be passed at least two parameters",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class RefasterAnyOfUsageCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+public final class RefasterAnyOfUsage extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> REFASTER_ANY_OF =
       staticMethod().onClass(Refaster.class.getName()).named("anyOf");
@@ -46,7 +45,8 @@ public final class RefasterAnyOfUsageCheck extends BugChecker
         case 1:
           return describeMatch(
               tree,
-              SuggestedFix.replace(tree, Util.treeToString(tree.getArguments().get(0), state)));
+              SuggestedFix.replace(
+                  tree, SourceCode.treeToString(tree.getArguments().get(0), state)));
         default:
           /* Handled below. */
       }

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

@@ -30,12 +30,11 @@ import com.sun.source.tree.Tree;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "RequestMappingAnnotation",
     summary = "Make sure all `@RequestMapping` method parameters are annotated",
     linkType = NONE,
     severity = WARNING,
     tags = LIKELY_ERROR)
-public final class RequestMappingAnnotationCheck extends BugChecker implements MethodTreeMatcher {
+public final class RequestMappingAnnotation extends BugChecker implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String ANN_PACKAGE_PREFIX = "org.springframework.web.bind.annotation.";
   // XXX: Generalize this logic to fully support Spring meta-annotations, then update the class
@@ -64,9 +63,11 @@ public final class RequestMappingAnnotationCheck extends BugChecker implements M
                       AT_LEAST_ONE,
                       anyOf(
                           isType(ANN_PACKAGE_PREFIX + "PathVariable"),
+                          isType(ANN_PACKAGE_PREFIX + "RequestAttribute"),
                           isType(ANN_PACKAGE_PREFIX + "RequestBody"),
                           isType(ANN_PACKAGE_PREFIX + "RequestHeader"),
-                          isType(ANN_PACKAGE_PREFIX + "RequestParam"))),
+                          isType(ANN_PACKAGE_PREFIX + "RequestParam"),
+                          isType(ANN_PACKAGE_PREFIX + "RequestPart"))),
                   isSameType("java.io.InputStream"),
                   isSameType("java.time.ZoneId"),
                   isSameType("java.util.Locale"),

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

@@ -24,12 +24,11 @@ import com.sun.source.tree.VariableTree;
 /** A {@link BugChecker} which flags {@code @RequestParam} parameters with an unsupported type. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "RequestParamType",
     summary = "`@RequestParam` does not support `ImmutableCollection` and `ImmutableMap` subtypes",
     linkType = NONE,
     severity = ERROR,
     tags = LIKELY_ERROR)
-public final class RequestParamTypeCheck extends BugChecker implements VariableTreeMatcher {
+public final class RequestParamType extends BugChecker implements VariableTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<VariableTree> HAS_UNSUPPORTED_REQUEST_PARAM =
       allOf(

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

@@ -32,12 +32,11 @@ import com.sun.source.tree.Tree;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "ScheduledTransactionTrace",
     summary = "Scheduled operation must start a new New Relic transaction",
     linkType = NONE,
     severity = ERROR,
     tags = LIKELY_ERROR)
-public final class ScheduledTransactionTraceCheck extends BugChecker implements MethodTreeMatcher {
+public final class ScheduledTransactionTrace extends BugChecker implements MethodTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String TRACE_ANNOTATION_FQCN = "com.newrelic.api.agent.Trace";
   private static final Matcher<Tree> IS_SCHEDULED =
@@ -75,7 +74,7 @@ public final class ScheduledTransactionTraceCheck extends BugChecker implements
     return describeMatch(
         traceAnnotation,
         SuggestedFixes.updateAnnotationArgumentValues(
-                traceAnnotation, "dispatcher", ImmutableList.of("true"))
+                traceAnnotation, state, "dispatcher", ImmutableList.of("true"))
             .build());
   }
 

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

@@ -22,6 +22,7 @@ import com.sun.source.tree.MethodInvocationTree;
 import com.sun.source.tree.Tree.Kind;
 import java.util.List;
 import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /** A {@link BugChecker} which flags SLF4J usages that are likely to be in error. */
 // XXX: The special-casing of Throwable applies only to SLF4J 1.6.0+; see
@@ -31,13 +32,11 @@ import java.util.Optional;
 // preconditions, ...
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "Slf4jLogStatement",
     summary = "Make sure SLF4J log statements contain proper placeholders with matching arguments",
     linkType = NONE,
     severity = WARNING,
     tags = LIKELY_ERROR)
-public final class Slf4jLogStatementCheck extends BugChecker
-    implements MethodInvocationTreeMatcher {
+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> THROWABLE = isSubtypeOf(Throwable.class);
@@ -114,7 +113,7 @@ public final class Slf4jLogStatementCheck extends BugChecker
        * replaced at this usage site.
        */
       description.addFix(
-          SuggestedFix.replace(tree, Util.treeToString(tree, state).replace("%s", "{}")));
+          SuggestedFix.replace(tree, SourceCode.treeToString(tree, state).replace("%s", "{}")));
     }
 
     return false;

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

@@ -25,6 +25,8 @@ import com.sun.source.tree.MemberSelectTree;
 import com.sun.source.tree.NewArrayTree;
 import com.sun.source.tree.Tree.Kind;
 import java.util.Optional;
+import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
+import tech.picnic.errorprone.bugpatterns.util.SourceCode;
 
 /**
  * A {@link BugChecker} which flags {@code @RequestMapping} annotations that can be written more
@@ -32,13 +34,12 @@ import java.util.Optional;
  */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "SpringMvcAnnotation",
     summary =
         "Prefer the conciseness of `@{Get,Put,Post,Delete,Patch}Mapping` over `@RequestMapping`",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class SpringMvcAnnotationCheck extends BugChecker implements AnnotationTreeMatcher {
+public final class SpringMvcAnnotation extends BugChecker implements AnnotationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final String ANN_PACKAGE_PREFIX = "org.springframework.web.bind.annotation.";
   private static final AnnotationAttributeMatcher ARGUMENT_SELECTOR =
@@ -92,7 +93,7 @@ public final class SpringMvcAnnotationCheck extends BugChecker implements Annota
   private static String extractMethod(ExpressionTree expr, VisitorState state) {
     switch (expr.getKind()) {
       case IDENTIFIER:
-        return Util.treeToString(expr, state);
+        return SourceCode.treeToString(expr, state);
       case MEMBER_SELECT:
         return ((MemberSelectTree) expr).getIdentifier().toString();
       default:
@@ -105,7 +106,7 @@ public final class SpringMvcAnnotationCheck extends BugChecker implements Annota
     String newArguments =
         tree.getArguments().stream()
             .filter(not(argToRemove::equals))
-            .map(arg -> Util.treeToString(arg, state))
+            .map(arg -> SourceCode.treeToString(arg, state))
             .collect(joining(", "));
 
     return SuggestedFix.builder()

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

@@ -45,12 +45,11 @@ import java.util.Optional;
 // - Likely any of `*.{ZERO, ONE, MIX, MAX, MIN_VALUE, MAX_VALUE}`.
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "StaticImport",
     summary = "Identifier should be statically imported",
     linkType = NONE,
     severity = SUGGESTION,
     tags = SIMPLIFICATION)
-public final class StaticImportCheck extends BugChecker implements MemberSelectTreeMatcher {
+public final class StaticImport extends BugChecker implements MemberSelectTreeMatcher {
   private static final long serialVersionUID = 1L;
 
   /**
@@ -67,6 +66,7 @@ public final class StaticImportCheck extends BugChecker implements MemberSelectT
           "com.google.errorprone.BugPattern.LinkType",
           "com.google.errorprone.BugPattern.SeverityLevel",
           "com.google.errorprone.BugPattern.StandardTags",
+          "com.google.errorprone.matchers.Matchers",
           "com.google.errorprone.refaster.ImportPolicy",
           "com.mongodb.client.model.Accumulators",
           "com.mongodb.client.model.Aggregates",

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

@@ -29,13 +29,12 @@ import java.time.LocalTime;
 /** A {@link BugChecker} which flags illegal time-zone related operations. */
 @AutoService(BugChecker.class)
 @BugPattern(
-    name = "TimeZoneUsage",
     summary =
         "Derive the current time from an existing `Clock` Spring bean, and don't rely on a `Clock`'s time zone",
     linkType = NONE,
     severity = WARNING,
     tags = FRAGILE_CODE)
-public final class TimeZoneUsageCheck extends BugChecker implements MethodInvocationTreeMatcher {
+public final class TimeZoneUsage extends BugChecker implements MethodInvocationTreeMatcher {
   private static final long serialVersionUID = 1L;
   private static final Matcher<ExpressionTree> BANNED_TIME_METHOD =
       anyOf(
@@ -59,7 +58,7 @@ public final class TimeZoneUsageCheck extends BugChecker implements MethodInvoca
                   LocalDateTime.class.getName(),
                   LocalTime.class.getName())
               .named("now"),
-          staticMethod().onClassAny(Instant.class.getName()).named("now").withParameters());
+          staticMethod().onClassAny(Instant.class.getName()).named("now").withNoParameters());
 
   @Override
   public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {

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

@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.bugpatterns;
+package tech.picnic.errorprone.bugpatterns.util;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.HashMultimap;
@@ -28,7 +28,7 @@ import java.util.stream.Stream;
  * <p>This class allows one to define a whitelist or blacklist of annotations or their attributes.
  * Annotations are identified by their fully qualified name.
  */
-final class AnnotationAttributeMatcher implements Serializable {
+public final class AnnotationAttributeMatcher implements Serializable {
   private static final long serialVersionUID = 1L;
 
   private final boolean complement;
@@ -59,7 +59,7 @@ final class AnnotationAttributeMatcher implements Serializable {
    * @param exclusions The listed annotations or annotation attributes are not matched.
    * @return A non-{@code null} {@link AnnotationAttributeMatcher}.
    */
-  static AnnotationAttributeMatcher create(
+  public static AnnotationAttributeMatcher create(
       Optional<? extends List<String>> inclusions, Iterable<String> exclusions) {
     Set<String> includedWholeTypes = new HashSet<>();
     Set<String> excludedWholeTypes = new HashSet<>();
@@ -97,7 +97,13 @@ final class AnnotationAttributeMatcher implements Serializable {
     }
   }
 
-  Stream<? extends ExpressionTree> extractMatchingArguments(AnnotationTree tree) {
+  /**
+   * Returns the subset of arguments of the given {@link AnnotationTree} matched by this instance.
+   *
+   * @param tree The annotation AST node to be inspected.
+   * @return Any matching annotation arguments.
+   */
+  public Stream<? extends ExpressionTree> extractMatchingArguments(AnnotationTree tree) {
     Type type = ASTHelpers.getType(tree.getAnnotationType());
     if (type == null) {
       return Stream.empty();

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

@@ -1,9 +1,10 @@
-package tech.picnic.errorprone.bugpatterns;
+package tech.picnic.errorprone.bugpatterns.util;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets;
 
-final class JavaKeywords {
+/** Utility class that can be used to identify reserved keywords of the Java language. */
+public final class JavaKeywords {
   /**
    * List of all reserved keywords in the Java language.
    *
@@ -95,17 +96,33 @@ final class JavaKeywords {
 
   private JavaKeywords() {}
 
-  /** Tells whether the given string is a reserved keyword in the Java language. */
+  /**
+   * Tells whether the given string is a reserved keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a reserved keyword in the Java language.
+   */
   public static boolean isReservedKeyword(String str) {
     return RESERVED_KEYWORDS.contains(str);
   }
 
-  /** Tells whether the given string is a contextual keyword in the Java language. */
+  /**
+   * Tells whether the given string is a contextual keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a contextual keyword in the Java language.
+   */
   public static boolean isContextualKeyword(String str) {
     return CONTEXTUAL_KEYWORDS.contains(str);
   }
 
-  /** Tells whether the given string is a reserved or contextual keyword in the Java language. */
+  /**
+   * Tells whether the given string is a reserved or contextual keyword in the Java language.
+   *
+   * @param str The string of interest.
+   * @return {@code true} if the given string is a reserved or contextual keyword in the Java
+   *     language.
+   */
   public static boolean isKeyword(String str) {
     return ALL_KEYWORDS.contains(str);
   }

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

@@ -1,4 +1,4 @@
-package tech.picnic.errorprone.bugpatterns;
+package tech.picnic.errorprone.bugpatterns.util;
 
 import static com.google.common.base.Preconditions.checkArgument;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
@@ -15,13 +15,20 @@ import java.util.regex.Pattern;
 /** A method invocation expression {@link Matcher} factory. */
 // XXX: Document better. The expressions accepted here could also be defined using `MethodMatchers`.
 // So explain why this class is still useful.
-final class MethodMatcherFactory {
+public final class MethodMatcherFactory {
   private static final Splitter ARGUMENT_TYPE_SPLITTER =
       Splitter.on(',').trimResults().omitEmptyStrings();
   private static final Pattern METHOD_SIGNATURE =
       Pattern.compile("([^\\s#(,)]+)#([^\\s#(,)]+)\\(((?:[^\\s#(,)]+(?:,[^\\s#(,)]+)*)?)\\)");
 
-  Matcher<ExpressionTree> create(Collection<String> signatures) {
+  /**
+   * Creates a {@link Matcher} of methods with any of the given signatures.
+   *
+   * @param signatures The method signatures of interest.
+   * @return A new {@link Matcher} which accepts invocation expressions of any method identified by
+   *     the given signatures.
+   */
+  public Matcher<ExpressionTree> create(Collection<String> signatures) {
     return anyOf(
         signatures.stream()
             .map(MethodMatcherFactory::createMethodMatcher)

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

@@ -1,19 +1,26 @@
-package tech.picnic.errorprone.bugpatterns;
+package tech.picnic.errorprone.bugpatterns.util;
 
 import com.google.errorprone.VisitorState;
 import com.sun.source.tree.Tree;
 
+/**
+ * A collection of Error Prone utility methods for dealing with the source code representation of
+ * AST nodes.
+ */
 // XXX: Can we locate this code in a better place? Maybe contribute it upstream?
-final class Util {
-  private Util() {}
+public final class SourceCode {
+  private SourceCode() {}
 
   /**
    * Returns a string representation of the given {@link Tree}, preferring the original source code
    * (if available) over its prettified representation.
    *
+   * @param tree The AST node of interest.
+   * @param state A {@link VisitorState} describing the context in which the given {@link Tree} is
+   *     found.
    * @return A non-{@code null} string.
    */
-  static String treeToString(Tree tree, VisitorState state) {
+  public static String treeToString(Tree tree, VisitorState state) {
     String src = state.getSourceForNode(tree);
     return src != null ? src : tree.toString();
   }

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

@@ -0,0 +1,4 @@
+/** Auxiliary utilities for use by Error Prone checks. */
+@com.google.errorprone.annotations.CheckReturnValue
+@javax.annotation.ParametersAreNonnullByDefault
+package tech.picnic.errorprone.bugpatterns.util;

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJComparableTemplates.java

@@ -0,0 +1,92 @@
+package tech.picnic.errorprone.refastertemplates;
+
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import org.assertj.core.api.AbstractComparableAssert;
+import org.assertj.core.api.AbstractIntegerAssert;
+
+final class AssertJComparableTemplates {
+  private AssertJComparableTemplates() {}
+
+  static final class AssertThatIsEqualByComparingTo<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(T actual, T expected) {
+      return assertThat(actual.compareTo(expected)).isEqualTo(0);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractComparableAssert<?, ?> after(T actual, T expected) {
+      return assertThat(actual).isEqualByComparingTo(expected);
+    }
+  }
+
+  static final class AssertThatIsNotEqualByComparingTo<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(T actual, T expected) {
+      return assertThat(actual.compareTo(expected)).isNotEqualTo(0);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractComparableAssert<?, ?> after(T actual, T expected) {
+      return assertThat(actual).isNotEqualByComparingTo(expected);
+    }
+  }
+
+  static final class AssertThatIsLessThan<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(T actual, T expected) {
+      return assertThat(actual.compareTo(expected)).isNegative();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractComparableAssert<?, ?> after(T actual, T expected) {
+      return assertThat(actual).isLessThan(expected);
+    }
+  }
+
+  static final class AssertThatIsLessThanOrEqualTo<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(T actual, T expected) {
+      return assertThat(actual.compareTo(expected)).isNotPositive();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractComparableAssert<?, ?> after(T actual, T expected) {
+      return assertThat(actual).isLessThanOrEqualTo(expected);
+    }
+  }
+
+  static final class AssertThatIsGreaterThan<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(T actual, T expected) {
+      return assertThat(actual.compareTo(expected)).isPositive();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractComparableAssert<?, ?> after(T actual, T expected) {
+      return assertThat(actual).isGreaterThan(expected);
+    }
+  }
+
+  static final class AssertThatIsGreaterThanOrEqualTo<T extends Comparable<? super T>> {
+    @BeforeTemplate
+    AbstractIntegerAssert<?> before(T actual, T expected) {
+      return assertThat(actual.compareTo(expected)).isNotNegative();
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractComparableAssert<?, ?> after(T actual, T expected) {
+      return assertThat(actual).isGreaterThanOrEqualTo(expected);
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJNumberTemplates.java

@@ -6,6 +6,7 @@ import static org.assertj.core.api.Assertions.assertThat;
 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.NotMatches;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.math.BigDecimal;
 import java.math.BigInteger;
@@ -18,6 +19,7 @@ import org.assertj.core.api.AbstractIntegerAssert;
 import org.assertj.core.api.AbstractLongAssert;
 import org.assertj.core.api.AbstractShortAssert;
 import org.assertj.core.api.NumberAssert;
+import tech.picnic.errorprone.refaster.util.IsCharacter;
 
 final class AssertJNumberTemplates {
   private AssertJNumberTemplates() {}
@@ -226,9 +228,16 @@ final class AssertJNumberTemplates {
     }
   }
 
+  /**
+   * Prefer {@link AbstractLongAssert#isOdd()} (and similar methods for other {@link NumberAssert}
+   * subtypes) over alternatives with less informative error messages.
+   *
+   * <p>Note that {@link org.assertj.core.api.AbstractCharacterAssert} does not implement {@link
+   * NumberAssert} and does not provide an {@code isOdd} test.
+   */
   static final class AssertThatIsOdd {
     @BeforeTemplate
-    AbstractIntegerAssert<?> before(int number) {
+    AbstractIntegerAssert<?> before(@NotMatches(IsCharacter.class) int number) {
       return assertThat(number % 2).isEqualTo(1);
     }
 
@@ -244,9 +253,16 @@ final class AssertJNumberTemplates {
     }
   }
 
+  /**
+   * Prefer {@link AbstractLongAssert#isEven()} (and similar methods for other {@link NumberAssert}
+   * subtypes) over alternatives with less informative error messages.
+   *
+   * <p>Note that {@link org.assertj.core.api.AbstractCharacterAssert} does not implement {@link
+   * NumberAssert} and does not provide an {@code isEven} test.
+   */
   static final class AssertThatIsEven {
     @BeforeTemplate
-    AbstractIntegerAssert<?> before(int number) {
+    AbstractIntegerAssert<?> before(@NotMatches(IsCharacter.class) int number) {
       return assertThat(number % 2).isEqualTo(0);
     }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJPrimitiveTemplates.java

@@ -0,0 +1,111 @@
+package tech.picnic.errorprone.refastertemplates;
+
+import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.google.errorprone.refaster.Refaster;
+import com.google.errorprone.refaster.annotation.AfterTemplate;
+import com.google.errorprone.refaster.annotation.BeforeTemplate;
+import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import org.assertj.core.api.AbstractBooleanAssert;
+import org.assertj.core.api.AbstractDoubleAssert;
+
+final class AssertJPrimitiveTemplates {
+  private AssertJPrimitiveTemplates() {}
+
+  static final class AssertThatIsEqualTo {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(boolean actual, boolean expected) {
+      return Refaster.anyOf(
+          assertThat(actual == expected).isTrue(), assertThat(actual != expected).isFalse());
+    }
+
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(double actual, double expected) {
+      return Refaster.anyOf(
+          assertThat(actual == expected).isTrue(), assertThat(actual != expected).isFalse());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractBooleanAssert<?> after(boolean actual, boolean expected) {
+      return assertThat(actual).isEqualTo(expected);
+    }
+  }
+
+  static final class AssertThatIsNotEqualTo {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(boolean actual, boolean expected) {
+      return Refaster.anyOf(
+          assertThat(actual != expected).isTrue(), assertThat(actual == expected).isFalse());
+    }
+
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(double actual, double expected) {
+      return Refaster.anyOf(
+          assertThat(actual != expected).isTrue(), assertThat(actual == expected).isFalse());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractBooleanAssert<?> after(boolean actual, boolean expected) {
+      return assertThat(actual).isNotEqualTo(expected);
+    }
+  }
+
+  static final class AssertThatIsLessThan {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(double actual, double expected) {
+      return Refaster.anyOf(
+          assertThat(actual < expected).isTrue(), assertThat(actual >= expected).isFalse());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractDoubleAssert<?> after(double actual, double expected) {
+      return assertThat(actual).isLessThan(expected);
+    }
+  }
+
+  static final class AssertThatIsLessThanOrEqualTo {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(double actual, double expected) {
+      return Refaster.anyOf(
+          assertThat(actual <= expected).isTrue(), assertThat(actual > expected).isFalse());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractDoubleAssert<?> after(double actual, double expected) {
+      return assertThat(actual).isLessThanOrEqualTo(expected);
+    }
+  }
+
+  static final class AssertThatIsGreaterThan {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(double actual, double expected) {
+      return Refaster.anyOf(
+          assertThat(actual > expected).isTrue(), assertThat(actual <= expected).isFalse());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractDoubleAssert<?> after(double actual, double expected) {
+      return assertThat(actual).isGreaterThan(expected);
+    }
+  }
+
+  static final class AssertThatIsGreaterThanOrEqualTo {
+    @BeforeTemplate
+    AbstractBooleanAssert<?> before(double actual, double expected) {
+      return Refaster.anyOf(
+          assertThat(actual >= expected).isTrue(), assertThat(actual < expected).isFalse());
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractDoubleAssert<?> after(double actual, double expected) {
+      return assertThat(actual).isGreaterThanOrEqualTo(expected);
+    }
+  }
+}

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/AssertJThrowingCallableTemplates.java

@@ -59,6 +59,27 @@ final class AssertJThrowingCallableTemplates {
     }
   }
 
+  static final class AssertThatThrownByIllegalArgumentExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalArgumentException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatIllegalArgumentException()
+          .isThrownBy(throwingCallable)
+          .withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalArgumentException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
   static final class AssertThatThrownByIllegalArgumentExceptionHasMessageStartingWith {
     @BeforeTemplate
     @SuppressWarnings(
@@ -148,6 +169,27 @@ final class AssertJThrowingCallableTemplates {
     }
   }
 
+  static final class AssertThatThrownByIllegalStateExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIllegalStateException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatIllegalStateException()
+          .isThrownBy(throwingCallable)
+          .withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IllegalStateException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
   static final class AssertThatThrownByIllegalStateExceptionHasMessageStartingWith {
     @BeforeTemplate
     @SuppressWarnings(
@@ -235,6 +277,27 @@ final class AssertJThrowingCallableTemplates {
     }
   }
 
+  static final class AssertThatThrownByNullPointerExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByNullPointerException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatNullPointerException()
+          .isThrownBy(throwingCallable)
+          .withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(NullPointerException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
   static final class AssertThatThrownByNullPointerExceptionHasMessageStartingWith {
     @BeforeTemplate
     @SuppressWarnings(
@@ -268,9 +331,9 @@ final class AssertJThrowingCallableTemplates {
   }
 
   static final class AssertThatThrownByIOExceptionHasMessage {
+    @BeforeTemplate
     @SuppressWarnings(
         "AssertThatThrownByIOException" /* Matches strictly more specific expressions. */)
-    @BeforeTemplate
     AbstractObjectAssert<?, ?> before(ThrowingCallable throwingCallable, String message) {
       return assertThatIOException().isThrownBy(throwingCallable).withMessage(message);
     }
@@ -284,6 +347,25 @@ final class AssertJThrowingCallableTemplates {
     }
   }
 
+  static final class AssertThatThrownByIOExceptionHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings(
+        "AssertThatThrownByIOException" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatIOException().isThrownBy(throwingCallable).withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        ThrowingCallable throwingCallable, String message, @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(IOException.class)
+          .hasMessage(message, parameters);
+    }
+  }
+
   static final class AssertThatThrownBy {
     @BeforeTemplate
     AbstractObjectAssert<?, ?> before(
@@ -321,6 +403,32 @@ final class AssertJThrowingCallableTemplates {
     }
   }
 
+  static final class AssertThatThrownByHasMessageParameters {
+    @BeforeTemplate
+    @SuppressWarnings("AssertThatThrownBy" /* Matches strictly more specific expressions. */)
+    AbstractObjectAssert<?, ?> before(
+        Class<? extends Throwable> exceptionType,
+        ThrowingCallable throwingCallable,
+        String message,
+        @Repeated Object parameters) {
+      return assertThatExceptionOfType(exceptionType)
+          .isThrownBy(throwingCallable)
+          .withMessage(message, parameters);
+    }
+
+    @AfterTemplate
+    @UseImportPolicy(STATIC_IMPORT_ALWAYS)
+    AbstractObjectAssert<?, ?> after(
+        Class<? extends Throwable> exceptionType,
+        ThrowingCallable throwingCallable,
+        String message,
+        @Repeated Object parameters) {
+      return assertThatThrownBy(throwingCallable)
+          .isInstanceOf(exceptionType)
+          .hasMessage(message, parameters);
+    }
+  }
+
   // XXX: Drop this template in favour of a generic Error Prone check which flags
   // `String.format(...)` arguments to a wide range of format methods.
   static final class AbstractThrowableAssertHasMessage {

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/CollectionTemplates.java

@@ -15,6 +15,7 @@ import java.util.List;
 import java.util.NavigableSet;
 import java.util.Optional;
 import java.util.Queue;
+import java.util.Set;
 import java.util.SortedSet;
 import java.util.function.IntFunction;
 import java.util.stream.Stream;
@@ -129,31 +130,32 @@ final class CollectionTemplates {
     }
   }
 
-  static final class CollectionRemoveAllFromCollectionBlock<T, S extends T> {
+  static final class SetRemoveAllCollection<T, S extends T> {
     @BeforeTemplate
-    void before(Collection<T> removeTo, Collection<S> elementsToRemove) {
-      elementsToRemove.forEach(removeTo::remove);
+    void before(Set<T> removeFrom, Collection<S> elementsToRemove) {
+      elementsToRemove.forEach(removeFrom::remove);
     }
 
     @BeforeTemplate
-    void before2(Collection<T> removeTo, Collection<S> elementsToRemove) {
+    void before2(Set<T> removeFrom, Collection<S> elementsToRemove) {
       for (T element : elementsToRemove) {
-        removeTo.remove(element);
+        removeFrom.remove(element);
       }
     }
 
     // XXX: This method is identical to `before2` except for the loop type. Make Refaster smarter so
-    // that this is supported out of the box.
+    // that this is supported out of the box. After doing so, also drop the `S extends T` type
+    // constraint; ideally this check applies to any `S`.
     @BeforeTemplate
-    void before3(Collection<T> removeTo, Collection<S> elementsToRemove) {
+    void before3(Set<T> removeFrom, Collection<S> elementsToRemove) {
       for (S element : elementsToRemove) {
-        removeTo.remove(element);
+        removeFrom.remove(element);
       }
     }
 
     @AfterTemplate
-    void after(Collection<T> removeTo, Collection<S> elementsToRemove) {
-      removeTo.removeAll(elementsToRemove);
+    void after(Set<T> removeFrom, Collection<S> elementsToRemove) {
+      removeFrom.removeAll(elementsToRemove);
     }
   }
 

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/EqualityTemplates.java

@@ -20,7 +20,7 @@ final class EqualityTemplates {
      * remaining reference-based equality checks.
      */
     // 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 RefasterCheck.
+    // work around the issue by selecting the "largest replacements". See the `Refaster` check.
     @BeforeTemplate
     boolean before(T a, T b) {
       return Refaster.anyOf(a.equals(b), Objects.equals(a, b));
@@ -34,21 +34,18 @@ final class EqualityTemplates {
   }
 
   /** Prefer {@link Object#equals(Object)} over the equivalent lambda function. */
-  // XXX: As it stands, this rule is a special case of what `MethodReferenceUsageCheck` tries to
-  // achieve. If/when `MethodReferenceUsageCheck` becomes production ready, we should simply drop
-  // this check.
+  // 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.
   // XXX: Alternatively, the rule should be replaced with a plugin which also identifies cases where
   // the arguments are swapped but simplification is possible anyway, by virtue of `v` being
   // non-null.
   static final class EqualsPredicate<T> {
     @BeforeTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Predicate<T> before(T v) {
       return e -> v.equals(e);
     }
 
     @AfterTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Predicate<T> after(T v) {
       return v::equals;
     }
@@ -71,17 +68,14 @@ final class EqualityTemplates {
    * Don't negate an equality test or use the ternary operator to compare two booleans; directly
    * test for inequality instead.
    */
+  // XXX: Replacing `a ? !b : b` with `a != b` changes semantics if both `a` and `b` are boxed
+  // booleans.
   static final class Negation {
     @BeforeTemplate
     boolean before(boolean a, boolean b) {
       return Refaster.anyOf(!(a == b), a ? !b : b);
     }
 
-    @BeforeTemplate
-    boolean before(long a, long b) {
-      return !(a == b);
-    }
-
     @BeforeTemplate
     boolean before(double a, double b) {
       return !(a == b);
@@ -102,17 +96,14 @@ final class EqualityTemplates {
    * Don't negate an inequality test or use the ternary operator to compare two booleans; directly
    * test for equality instead.
    */
+  // XXX: Replacing `a ? b : !b` with `a == b` changes semantics if both `a` and `b` are boxed
+  // booleans.
   static final class IndirectDoubleNegation {
     @BeforeTemplate
     boolean before(boolean a, boolean b) {
       return Refaster.anyOf(!(a != b), a ? b : !b);
     }
 
-    @BeforeTemplate
-    boolean before(long a, long b) {
-      return !(a != b);
-    }
-
     @BeforeTemplate
     boolean before(double a, double b) {
       return !(a != b);

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableListMultimapTemplates.java

@@ -92,7 +92,7 @@ final class ImmutableListMultimapTemplates {
    */
   static final class EntryToImmutableListMultimap<K, V> {
     @BeforeTemplate
-    ImmutableMultimap<K, V> before(Map.Entry<? extends K, ? extends V> entry) {
+    ImmutableListMultimap<K, V> before(Map.Entry<? extends K, ? extends V> entry) {
       return Refaster.anyOf(
           ImmutableListMultimap.<K, V>builder().put(entry).build(),
           Stream.of(entry)

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableListTemplates.java

@@ -6,8 +6,6 @@ import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Collections.emptyList;
 import static java.util.Collections.singletonList;
 import static java.util.Comparator.naturalOrder;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
@@ -78,17 +76,11 @@ final class ImmutableListTemplates {
     }
   }
 
-  /** Prefer {@link ImmutableList#toImmutableList()} over the more verbose alternative. */
-  // XXX: Once the code base has been sufficiently cleaned up, we might want to also rewrite
-  // `Collectors.toList(`), with the caveat that it allows mutation (though this cannot be relied
-  // upon) as well as nulls. Another option is to explicitly rewrite those variants to
-  // `Collectors.toSet(ArrayList::new)`.
+  /** Prefer {@link ImmutableList#toImmutableList()} over less idiomatic alternatives. */
   static final class StreamToImmutableList<T> {
     @BeforeTemplate
     ImmutableList<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableList.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableList::copyOf)));
+      return ImmutableList.copyOf(stream.iterator());
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableMapTemplates.java

@@ -192,7 +192,7 @@ final class ImmutableMapTemplates {
 
     // XXX: Instead of `Map.Entry::getKey` we could also match `e -> e.getKey()`. But for some
     // reason Refaster doesn't handle that case. This doesn't matter if we roll out use of
-    // `MethodReferenceUsageCheck`. Same observation applies to a lot of other Refaster checks.
+    // `MethodReferenceUsage`. Same observation applies to a lot of other Refaster checks.
     @BeforeTemplate
     @SuppressWarnings("NullAway")
     ImmutableMap<K, V2> before(Map<K, V1> map) {

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableMultisetTemplates.java

@@ -2,8 +2,6 @@ package tech.picnic.errorprone.refastertemplates;
 
 import static com.google.common.collect.ImmutableMultiset.toImmutableMultiset;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
 
 import com.google.common.collect.ImmutableMultiset;
 import com.google.common.collect.Streams;
@@ -90,9 +88,7 @@ final class ImmutableMultisetTemplates {
   static final class StreamToImmutableMultiset<T> {
     @BeforeTemplate
     ImmutableMultiset<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableMultiset.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableMultiset::copyOf)));
+      return ImmutableMultiset.copyOf(stream.iterator());
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableSetTemplates.java

@@ -4,9 +4,6 @@ import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Collections.emptySet;
 import static java.util.Collections.singleton;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
-import static java.util.stream.Collectors.toSet;
 
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Sets.SetView;
@@ -75,18 +72,11 @@ final class ImmutableSetTemplates {
   }
 
   /** Prefer {@link ImmutableSet#toImmutableSet()} over less idiomatic alternatives. */
-  // XXX: Once the code base has been sufficiently cleaned up, we might want to also rewrite
-  // `Collectors.toSet(`), with the caveat that it allows mutation (though this cannot be relied
-  // upon) as well as nulls. Another option is to explicitly rewrite those variants to
-  // `Collectors.toSet(HashSet::new)`.
   static final class StreamToImmutableSet<T> {
     @BeforeTemplate
     ImmutableSet<T> before(Stream<T> stream) {
       return Refaster.anyOf(
-          ImmutableSet.copyOf(stream.iterator()),
-          stream.distinct().collect(toImmutableSet()),
-          stream.collect(collectingAndThen(toList(), ImmutableSet::copyOf)),
-          stream.collect(collectingAndThen(toSet(), ImmutableSet::copyOf)));
+          ImmutableSet.copyOf(stream.iterator()), stream.distinct().collect(toImmutableSet()));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableSortedMultisetTemplates.java

@@ -3,10 +3,7 @@ package tech.picnic.errorprone.refastertemplates;
 import static com.google.common.collect.ImmutableSortedMultiset.toImmutableSortedMultiset;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.naturalOrder;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
 
-import com.google.common.collect.ImmutableMultiset;
 import com.google.common.collect.ImmutableSortedMultiset;
 import com.google.common.collect.Streams;
 import com.google.errorprone.refaster.Refaster;
@@ -93,14 +90,14 @@ final class ImmutableSortedMultisetTemplates {
   // `reverseOrder`.) Worth the hassle?
   static final class IterableToImmutableSortedMultiset<T extends Comparable<? super T>> {
     @BeforeTemplate
-    ImmutableMultiset<T> before(T[] iterable) {
+    ImmutableSortedMultiset<T> before(T[] iterable) {
       return Refaster.anyOf(
           ImmutableSortedMultiset.<T>naturalOrder().add(iterable).build(),
           Arrays.stream(iterable).collect(toImmutableSortedMultiset(naturalOrder())));
     }
 
     @BeforeTemplate
-    ImmutableMultiset<T> before(Iterator<T> iterable) {
+    ImmutableSortedMultiset<T> before(Iterator<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedMultiset.copyOf(naturalOrder(), iterable),
           ImmutableSortedMultiset.<T>naturalOrder().addAll(iterable).build(),
@@ -108,7 +105,7 @@ final class ImmutableSortedMultisetTemplates {
     }
 
     @BeforeTemplate
-    ImmutableMultiset<T> before(Iterable<T> iterable) {
+    ImmutableSortedMultiset<T> before(Iterable<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedMultiset.copyOf(naturalOrder(), iterable),
           ImmutableSortedMultiset.<T>naturalOrder().addAll(iterable).build(),
@@ -134,9 +131,7 @@ final class ImmutableSortedMultisetTemplates {
   static final class StreamToImmutableSortedMultiset<T extends Comparable<? super T>> {
     @BeforeTemplate
     ImmutableSortedMultiset<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableSortedMultiset.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableSortedMultiset::copyOf)));
+      return ImmutableSortedMultiset.copyOf(stream.iterator());
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ImmutableSortedSetTemplates.java

@@ -3,10 +3,7 @@ package tech.picnic.errorprone.refastertemplates;
 import static com.google.common.collect.ImmutableSortedSet.toImmutableSortedSet;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 import static java.util.Comparator.naturalOrder;
-import static java.util.stream.Collectors.collectingAndThen;
-import static java.util.stream.Collectors.toList;
 
-import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSortedSet;
 import com.google.common.collect.Streams;
 import com.google.errorprone.refaster.Refaster;
@@ -91,14 +88,14 @@ final class ImmutableSortedSetTemplates {
   // `reverseOrder`.) Worth the hassle?
   static final class IterableToImmutableSortedSet<T extends Comparable<? super T>> {
     @BeforeTemplate
-    ImmutableSet<T> before(T[] iterable) {
+    ImmutableSortedSet<T> before(T[] iterable) {
       return Refaster.anyOf(
           ImmutableSortedSet.<T>naturalOrder().add(iterable).build(),
           Arrays.stream(iterable).collect(toImmutableSortedSet(naturalOrder())));
     }
 
     @BeforeTemplate
-    ImmutableSet<T> before(Iterator<T> iterable) {
+    ImmutableSortedSet<T> before(Iterator<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedSet.copyOf(naturalOrder(), iterable),
           ImmutableSortedSet.<T>naturalOrder().addAll(iterable).build(),
@@ -106,7 +103,7 @@ final class ImmutableSortedSetTemplates {
     }
 
     @BeforeTemplate
-    ImmutableSet<T> before(Iterable<T> iterable) {
+    ImmutableSortedSet<T> before(Iterable<T> iterable) {
       return Refaster.anyOf(
           ImmutableSortedSet.copyOf(naturalOrder(), iterable),
           ImmutableSortedSet.<T>naturalOrder().addAll(iterable).build(),
@@ -134,9 +131,7 @@ final class ImmutableSortedSetTemplates {
   static final class StreamToImmutableSortedSet<T extends Comparable<? super T>> {
     @BeforeTemplate
     ImmutableSortedSet<T> before(Stream<T> stream) {
-      return Refaster.anyOf(
-          ImmutableSortedSet.copyOf(stream.iterator()),
-          stream.collect(collectingAndThen(toList(), ImmutableSortedSet::copyOf)));
+      return ImmutableSortedSet.copyOf(stream.iterator());
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/NullTemplates.java

@@ -9,11 +9,38 @@ import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.util.Objects;
 import java.util.function.Predicate;
+import javax.annotation.Nullable;
 
 /** Refaster templates related to expressions dealing with (possibly) null values. */
 final class NullTemplates {
   private NullTemplates() {}
 
+  /** Prefer the {@code ==} operator over {@link Objects#isNull(Object)}. */
+  static final class IsNull {
+    @BeforeTemplate
+    boolean before(@Nullable Object object) {
+      return Objects.isNull(object);
+    }
+
+    @AfterTemplate
+    boolean after(@Nullable Object object) {
+      return object == null;
+    }
+  }
+
+  /** Prefer the {@code !=} operator over {@link Objects#nonNull(Object)}. */
+  static final class IsNotNull {
+    @BeforeTemplate
+    boolean before(@Nullable Object object) {
+      return Objects.nonNull(object);
+    }
+
+    @AfterTemplate
+    boolean after(@Nullable Object object) {
+      return object != null;
+    }
+  }
+
   /** Prefer {@link Objects#requireNonNullElse(Object, Object)} over the Guava alternative. */
   // XXX: This rule is not valid in case `second` is `@Nullable`: in that case the Guava variant
   // will return `null`, while the JDK variant will throw an NPE.
@@ -33,13 +60,11 @@ final class NullTemplates {
   /** Prefer {@link Objects#isNull(Object)} over the equivalent lambda function. */
   static final class IsNullFunction<T> {
     @BeforeTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Predicate<T> before() {
       return o -> o == null;
     }
 
     @AfterTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Predicate<T> after() {
       return Objects::isNull;
     }
@@ -48,13 +73,11 @@ final class NullTemplates {
   /** Prefer {@link Objects#nonNull(Object)} over the equivalent lambda function. */
   static final class NonNullFunction<T> {
     @BeforeTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Predicate<T> before() {
       return o -> o != null;
     }
 
     @AfterTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Predicate<T> after() {
       return Objects::nonNull;
     }

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/OptionalTemplates.java

@@ -9,6 +9,7 @@ import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.MayOptionallyUse;
 import com.google.errorprone.refaster.annotation.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
+import java.util.Comparator;
 import java.util.Iterator;
 import java.util.Optional;
 import java.util.function.Function;
@@ -81,13 +82,11 @@ final class OptionalTemplates {
   // generalization. If/when Refaster is extended to understand this, delete the template above.
   static final class OptionalOrElseThrowMethodReference<T> {
     @BeforeTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Function<Optional<T>, T> before() {
       return Optional::get;
     }
 
     @AfterTemplate
-    @SuppressWarnings("NoFunctionalReturnType")
     Function<Optional<T>, T> after() {
       return Optional::orElseThrow;
     }
@@ -113,7 +112,7 @@ final class OptionalTemplates {
   /** Prefer {@link Optional#filter(Predicate)} over usage of the ternary operator. */
   // XXX: This rule may introduce a compilation error: the `test` expression may reference a
   // non-effectively final variable, which is not allowed in the replacement lambda expression.
-  // Maybe our RefasterCheck should test `compilesWithFix`?
+  // Maybe our `Refaster` checker should test `compilesWithFix`?
   abstract static class TernaryOperatorOptionalPositiveFiltering<T> {
     @Placeholder
     abstract boolean test(T value);
@@ -133,7 +132,7 @@ final class OptionalTemplates {
   /** Prefer {@link Optional#filter(Predicate)} over usage of the ternary operator. */
   // XXX: This rule may introduce a compilation error: the `test` expression may reference a
   // non-effectively final variable, which is not allowed in the replacement lambda expression.
-  // Maybe our RefasterCheck should test `compilesWithFix`?
+  // Maybe our `Refaster` checker should test `compilesWithFix`?
   abstract static class TernaryOperatorOptionalNegativeFiltering<T> {
     @Placeholder
     abstract boolean test(T value);
@@ -166,6 +165,11 @@ final class OptionalTemplates {
     }
   }
 
+  /**
+   * Prefer {@link Optional#map} over a {@link Optional#flatMap} which wraps the result of a
+   * transformation in an {@link Optional}; the former operation transforms {@code null} to {@link
+   * Optional#empty()}.
+   */
   abstract static class MapToNullable<T, S> {
     @Placeholder
     abstract S toNullableFunction(@MayOptionallyUse T element);
@@ -234,9 +238,16 @@ final class OptionalTemplates {
     }
   }
 
-  /** Within a stream's map operation unconditional {@link Optional#get()} calls can be avoided. */
-  // XXX: An alternative approach is to `.flatMap(Optional::stream)`. That may be a bit longer, but
-  // yield nicer code. Think about it.
+  /**
+   * Within a stream's map operation unconditional {@link Optional#orElseThrow()} calls can be
+   * avoided.
+   *
+   * <p><strong>Warning:</strong> this rewrite rule is not completely behavior preserving. The
+   * original code throws an exception if the mapping operation does not produce a value, while the
+   * replacement does not.
+   */
+  // XXX: An alternative approach is to use `.flatMap(Optional::stream)`. That may be a bit longer,
+  // but yields nicer code. Think about it.
   abstract static class StreamMapToOptionalGet<T, S> {
     @Placeholder
     abstract Optional<S> toOptionalFunction(@MayOptionallyUse T element);
@@ -306,6 +317,7 @@ final class OptionalTemplates {
   /** Prefer {@link Optional#or(Supplier)} over more verbose alternatives. */
   abstract static class OptionalOrOtherOptional<T> {
     @BeforeTemplate
+    @SuppressWarnings("NestedOptionals" /* Auto-fix for the `NestedOptionals` check. */)
     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.
@@ -321,6 +333,26 @@ final class OptionalTemplates {
     }
   }
 
+  /**
+   * Avoid unnecessary operations on an {@link Optional} that ultimately result in that very same
+   * {@link Optional}.
+   */
+  static final class OptionalIdentity<T> {
+    @BeforeTemplate
+    Optional<T> before(Optional<T> optional, Comparator<? super T> comparator) {
+      return Refaster.anyOf(
+          optional.stream().findFirst(),
+          optional.stream().findAny(),
+          optional.stream().min(comparator),
+          optional.stream().max(comparator));
+    }
+
+    @AfterTemplate
+    Optional<T> after(Optional<T> optional) {
+      return optional;
+    }
+  }
+
   // XXX: Add a rule for:
   // `optional.flatMap(x -> pred(x) ? Optional.empty() : Optional.of(x))` and variants.
   // (Maybe canonicalize the inner expression. Maybe we rewrite already.)

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/PrimitiveTemplates.java

@@ -10,11 +10,6 @@ final class PrimitiveTemplates {
 
   /** Avoid contrived ways of expressing the "less than" relationship. */
   static final class LessThan {
-    @BeforeTemplate
-    boolean before(long a, long b) {
-      return !(a >= b);
-    }
-
     @BeforeTemplate
     boolean before(double a, double b) {
       return !(a >= b);
@@ -28,11 +23,6 @@ final class PrimitiveTemplates {
 
   /** Avoid contrived ways of expressing the "less than or equal to" relationship. */
   static final class LessThanOrEqualTo {
-    @BeforeTemplate
-    boolean before(long a, long b) {
-      return !(a > b);
-    }
-
     @BeforeTemplate
     boolean before(double a, double b) {
       return !(a > b);
@@ -46,11 +36,6 @@ final class PrimitiveTemplates {
 
   /** Avoid contrived ways of expressing the "greater than" relationship. */
   static final class GreaterThan {
-    @BeforeTemplate
-    boolean before(long a, long b) {
-      return !(a <= b);
-    }
-
     @BeforeTemplate
     boolean before(double a, double b) {
       return !(a <= b);
@@ -64,11 +49,6 @@ final class PrimitiveTemplates {
 
   /** Avoid contrived ways of expressing the "greater than or equal to" relationship. */
   static final class GreaterThanOrEqualTo {
-    @BeforeTemplate
-    boolean before(long a, long b) {
-      return !(a < b);
-    }
-
     @BeforeTemplate
     boolean before(double a, double b) {
       return !(a < b);

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/ReactorTemplates.java

@@ -9,10 +9,12 @@ import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import com.google.errorprone.refaster.annotation.MayOptionallyUse;
+import com.google.errorprone.refaster.annotation.NotMatches;
 import com.google.errorprone.refaster.annotation.Placeholder;
 import com.google.errorprone.refaster.annotation.UseImportPolicy;
 import java.time.Duration;
 import java.util.Optional;
+import java.util.concurrent.Callable;
 import java.util.function.Consumer;
 import java.util.function.Function;
 import java.util.function.Predicate;
@@ -22,16 +24,35 @@ import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import reactor.test.StepVerifier;
 import reactor.test.publisher.PublisherProbe;
+import tech.picnic.errorprone.refaster.util.ThrowsCheckedException;
 
 /** Refaster templates related to Reactor expressions and statements. */
 final class ReactorTemplates {
   private ReactorTemplates() {}
 
+  /**
+   * Prefer {@link Mono#fromSupplier(Supplier)} over {@link Mono#fromCallable(Callable)} where
+   * feasible.
+   */
+  static final class MonoFromSupplier<T> {
+    @BeforeTemplate
+    Mono<T> before(@NotMatches(ThrowsCheckedException.class) Callable<? extends T> supplier) {
+      return Mono.fromCallable(supplier);
+    }
+
+    @AfterTemplate
+    Mono<T> after(Supplier<? extends T> supplier) {
+      return Mono.fromSupplier(supplier);
+    }
+  }
+
   /** Prefer {@link Mono#justOrEmpty(Optional)} over more verbose alternatives. */
   // XXX: If `optional` is a constant and effectively-final expression then the `Mono.defer` can be
   // dropped. Should look into Refaster support for identifying this.
   static final class MonoFromOptional<T> {
     @BeforeTemplate
+    @SuppressWarnings(
+        "MonoFromSupplier" /* `optional` may match a checked exception-throwing expression. */)
     Mono<T> before(Optional<T> optional) {
       return Refaster.anyOf(
           Mono.fromCallable(() -> optional.orElse(null)),
@@ -157,8 +178,8 @@ final class ReactorTemplates {
   }
 
   /**
-   * Prefer {@link Flux#concatMapIterable(Function)} over {@link Flux#concatMapIterable(Function)},
-   * as the former has equivalent semantics but a clearer name.
+   * Prefer {@link Flux#concatMapIterable(Function)} over {@link Flux#flatMapIterable(Function)}, as
+   * the former has equivalent semantics but a clearer name.
    */
   static final class FluxConcatMapIterable<T, S> {
     @BeforeTemplate
@@ -224,6 +245,32 @@ final class ReactorTemplates {
     }
   }
 
+  /** Prefer {@link Mono#cast(Class)} over {@link Mono#map(Function)} with a cast. */
+  static final class MonoCast<T, S> {
+    @BeforeTemplate
+    Mono<S> before(Mono<T> mono) {
+      return mono.map(Refaster.<S>clazz()::cast);
+    }
+
+    @AfterTemplate
+    Mono<S> after(Mono<T> mono) {
+      return mono.cast(Refaster.<S>clazz());
+    }
+  }
+
+  /** Prefer {@link Flux#cast(Class)} over {@link Flux#map(Function)} with a cast. */
+  static final class FluxCast<T, S> {
+    @BeforeTemplate
+    Flux<S> before(Flux<T> flux) {
+      return flux.map(Refaster.<S>clazz()::cast);
+    }
+
+    @AfterTemplate
+    Flux<S> after(Flux<T> flux) {
+      return flux.cast(Refaster.<S>clazz());
+    }
+  }
+
   /** Prefer {@link PublisherProbe#empty()}} over more verbose alternatives. */
   static final class PublisherProbeEmpty<T> {
     @BeforeTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/RxJava2AdapterTemplates.java

@@ -9,7 +9,7 @@ import io.reactivex.Flowable;
 import io.reactivex.Maybe;
 import io.reactivex.Observable;
 import io.reactivex.Single;
-import org.reactivestreams.Publisher;
+import org.jspecify.nullness.Nullable;
 import reactor.adapter.rxjava.RxJava2Adapter;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
@@ -21,14 +21,14 @@ final class RxJava2AdapterTemplates {
   /** Use the fluent API style when using {@link RxJava2Adapter#completableToMono}. */
   static final class CompletableToMono {
     @BeforeTemplate
-    Mono<Void> before(Completable completable) {
+    Mono<@Nullable Void> before(Completable completable) {
       return Refaster.anyOf(
           RxJava2Adapter.completableToMono(completable),
           completable.to(RxJava2Adapter::completableToMono));
     }
 
     @AfterTemplate
-    Mono<Void> after(Completable completable) {
+    Mono<@Nullable Void> after(Completable completable) {
       return completable.as(RxJava2Adapter::completableToMono);
     }
   }
@@ -39,12 +39,12 @@ final class RxJava2AdapterTemplates {
    */
   static final class FlowableToFlux<T> {
     @BeforeTemplate
-    Publisher<T> before(Flowable<T> flowable) {
+    Flux<T> before(Flowable<T> flowable) {
       return Refaster.anyOf(
-          flowable.compose(Flux::from),
+          Flux.from(flowable),
           flowable.to(Flux::from),
           flowable.as(Flux::from),
-          flowable.compose(RxJava2Adapter::flowableToFlux),
+          RxJava2Adapter.flowableToFlux(flowable),
           flowable.to(RxJava2Adapter::flowableToFlux));
     }
 
@@ -60,12 +60,11 @@ final class RxJava2AdapterTemplates {
    */
   static final class FluxToFlowable<T> {
     @BeforeTemplate
-    Publisher<T> before(Flux<T> flux) {
+    Flowable<T> before(Flux<T> flux) {
       return Refaster.anyOf(
           Flowable.fromPublisher(flux),
-          flux.transform(Flowable::fromPublisher),
           flux.as(Flowable::fromPublisher),
-          flux.transform(RxJava2Adapter::fluxToFlowable));
+          RxJava2Adapter.fluxToFlowable(flux));
     }
 
     @AfterTemplate
@@ -132,12 +131,11 @@ final class RxJava2AdapterTemplates {
    */
   static final class MonoToFlowable<T> {
     @BeforeTemplate
-    Publisher<T> before(Mono<T> mono) {
+    Flowable<T> before(Mono<T> mono) {
       return Refaster.anyOf(
           Flowable.fromPublisher(mono),
-          mono.transform(Flowable::fromPublisher),
           mono.as(Flowable::fromPublisher),
-          mono.transform(RxJava2Adapter::monoToFlowable));
+          RxJava2Adapter.monoToFlowable(mono));
     }
 
     @AfterTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/StringTemplates.java

@@ -13,7 +13,9 @@ import com.google.errorprone.refaster.annotation.AlsoNegation;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Objects;
 import java.util.Optional;
+import java.util.function.Function;
 import javax.annotation.Nullable;
 
 /** Refaster templates related to expressions dealing with {@link String}s. */
@@ -106,6 +108,40 @@ final class StringTemplates {
     }
   }
 
+  /**
+   * Prefer direct invocation of {@link String#valueOf(Object)} over the indirection introduced by
+   * {@link Objects#toString(Object)}.
+   */
+  static final class StringValueOf {
+    @BeforeTemplate
+    String before(Object object) {
+      return Objects.toString(object);
+    }
+
+    @AfterTemplate
+    String after(Object object) {
+      return String.valueOf(object);
+    }
+  }
+
+  /**
+   * Prefer direct delegation to {@link String#valueOf(Object)} over the indirection introduced by
+   * {@link Objects#toString(Object)}.
+   */
+  // XXX: This template is analogous to `StringValueOf` above. Arguably this is its generalization.
+  // If/when Refaster is extended to understand this, delete the template above.
+  static final class StringValueOfMethodReference {
+    @BeforeTemplate
+    Function<Object, String> before() {
+      return Objects::toString;
+    }
+
+    @AfterTemplate
+    Function<Object, String> after() {
+      return String::valueOf;
+    }
+  }
+
   /** Don't unnecessarily use the two-argument {@link String#substring(int, int)}. */
   static final class SubstringRemainder {
     @BeforeTemplate

error-prone-contrib/src/main/java/tech/picnic/errorprone/refastertemplates/WebClientTemplates.java

@@ -1,12 +1,25 @@
 package tech.picnic.errorprone.refastertemplates;
 
+import static org.springframework.http.HttpMethod.GET;
+import static org.springframework.http.HttpMethod.HEAD;
+import static org.springframework.http.HttpMethod.OPTIONS;
+import static org.springframework.http.HttpMethod.PATCH;
+import static org.springframework.http.HttpMethod.POST;
+import static org.springframework.http.HttpMethod.PUT;
 import static org.springframework.web.reactive.function.BodyInserters.fromValue;
 
+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.util.function.Function;
+import org.springframework.http.HttpMethod;
 import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.web.reactive.function.client.WebClient;
 import org.springframework.web.reactive.function.client.WebClient.RequestBodySpec;
+import org.springframework.web.reactive.function.client.WebClient.RequestBodyUriSpec;
 import org.springframework.web.reactive.function.client.WebClient.RequestHeadersSpec;
+import org.springframework.web.reactive.function.client.WebClient.RequestHeadersUriSpec;
 
 /**
  * Refaster templates related to expressions dealing with {@link
@@ -23,7 +36,7 @@ final class WebClientTemplates {
     }
 
     @BeforeTemplate
-    WebTestClient.RequestHeadersSpec<?> before2(
+    WebTestClient.RequestHeadersSpec<?> before(
         WebTestClient.RequestBodySpec requestBodySpec, T value) {
       return requestBodySpec.body(fromValue(value));
     }
@@ -33,4 +46,159 @@ final class WebClientTemplates {
       return requestBodySpec.bodyValue(value);
     }
   }
+
+  /**
+   * Prefer {@link WebClient#get()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#GET}.
+   */
+  static final class WebClientGet {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(WebClient webClient) {
+      return webClient.method(GET);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(WebTestClient webClient) {
+      return webClient.method(GET);
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(WebClient webClient) {
+      return webClient.get();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#head()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#HEAD}.
+   */
+  static final class WebClientHead {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(WebClient webClient) {
+      return webClient.method(HEAD);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(WebTestClient webClient) {
+      return webClient.method(HEAD);
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(WebClient webClient) {
+      return webClient.head();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#options()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#OPTIONS}.
+   */
+  static final class WebClientOptions {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(WebClient webClient) {
+      return webClient.method(OPTIONS);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(WebTestClient webClient) {
+      return webClient.method(OPTIONS);
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(WebClient webClient) {
+      return webClient.options();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#patch()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#PATCH}.
+   */
+  static final class WebClientPatch {
+    @BeforeTemplate
+    RequestBodyUriSpec before(WebClient webClient) {
+      return webClient.method(PATCH);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestBodyUriSpec before(WebTestClient webClient) {
+      return webClient.method(PATCH);
+    }
+
+    @AfterTemplate
+    RequestBodyUriSpec after(WebClient webClient) {
+      return webClient.patch();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#post()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#POST}.
+   */
+  static final class WebClientPost {
+    @BeforeTemplate
+    RequestBodyUriSpec before(WebClient webClient) {
+      return webClient.method(POST);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestBodyUriSpec before(WebTestClient webClient) {
+      return webClient.method(POST);
+    }
+
+    @AfterTemplate
+    RequestBodyUriSpec after(WebClient webClient) {
+      return webClient.post();
+    }
+  }
+
+  /**
+   * Prefer {@link WebClient#put()} over {@link WebClient#method(HttpMethod)} with {@link
+   * HttpMethod#PUT}.
+   */
+  static final class WebClientPut {
+    @BeforeTemplate
+    RequestBodyUriSpec before(WebClient webClient) {
+      return webClient.method(PUT);
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestBodyUriSpec before(WebTestClient webClient) {
+      return webClient.method(PUT);
+    }
+
+    @AfterTemplate
+    RequestBodyUriSpec after(WebClient webClient) {
+      return webClient.put();
+    }
+  }
+
+  /** Don't unnecessarily use {@link RequestHeadersUriSpec#uri(Function)}. */
+  abstract static class RequestHeadersUriSpecUri {
+    @BeforeTemplate
+    RequestHeadersSpec<?> before(
+        RequestHeadersUriSpec<?> requestHeadersUriSpec,
+        String path,
+        @Repeated Object uriVariables) {
+      return requestHeadersUriSpec.uri(
+          uriBuilder -> uriBuilder.path(path).build(Refaster.asVarargs(uriVariables)));
+    }
+
+    @BeforeTemplate
+    WebTestClient.RequestHeadersSpec<?> before(
+        WebTestClient.RequestHeadersUriSpec<?> requestHeadersUriSpec,
+        String path,
+        @Repeated Object uriVariables) {
+      return requestHeadersUriSpec.uri(
+          uriBuilder -> uriBuilder.path(path).build(Refaster.asVarargs(uriVariables)));
+    }
+
+    @AfterTemplate
+    RequestHeadersSpec<?> after(
+        RequestHeadersUriSpec<?> requestHeadersUriSpec,
+        String path,
+        @Repeated Object uriVariables) {
+      return requestHeadersUriSpec.uri(path, Refaster.asVarargs(uriVariables));
+    }
+  }
 }

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

@@ -6,14 +6,14 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-final class AmbiguousJsonCreatorCheckTest {
+final class AmbiguousJsonCreatorTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(AmbiguousJsonCreatorCheck.class, getClass())
+      CompilationTestHelper.newInstance(AmbiguousJsonCreator.class, getClass())
           .expectErrorMessage(
               "X",
               containsPattern("`JsonCreator.Mode` should be set for single-argument creators"));
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(AmbiguousJsonCreatorCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(AmbiguousJsonCreator.class, getClass());
 
   @Test
   void identification() {
@@ -112,7 +112,6 @@ final class AmbiguousJsonCreatorCheckTest {
             "      return new F(s);",
             "    }",
             "  }",
-            "",
             "}")
         .doTest();
   }

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

@@ -0,0 +1,64 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class AssertJIsNullTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(AssertJIsNull.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(AssertJIsNull.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    assertThat(1).isEqualTo(1);",
+            "    // BUG: Diagnostic contains:",
+            "    assertThat(1).isEqualTo(null);",
+            "    // BUG: Diagnostic contains:",
+            "    assertThat(\"foo\").isEqualTo(null);",
+            "    isEqualTo(null);",
+            "  }",
+            "",
+            "  private boolean isEqualTo(Object value) {",
+            "    return value.equals(\"bar\");",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    assertThat(1).isEqualTo(null);",
+            "    assertThat(\"foo\").isEqualTo(null);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static org.assertj.core.api.Assertions.assertThat;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    assertThat(1).isNull();",
+            "    assertThat(\"foo\").isNull();",
+            "  }",
+            "}")
+        .doTest(TEXT_MATCH);
+  }
+}

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

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class AutowiredConstructorCheckTest {
+final class AutowiredConstructorTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(AutowiredConstructorCheck.class, getClass());
+      CompilationTestHelper.newInstance(AutowiredConstructor.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(AutowiredConstructorCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(AutowiredConstructor.class, getClass());
 
   @Test
   void identification() {
@@ -27,27 +27,34 @@ public final class AutowiredConstructorCheckTest {
             "  }",
             "",
             "  class B {",
-            "    @Autowired void setProperty(Object o) {}",
+            "    @Autowired",
+            "    void setProperty(Object o) {}",
             "  }",
             "",
             "  class C {",
             "    // BUG: Diagnostic contains:",
-            "    @Autowired C() {}",
+            "    @Autowired",
+            "    C() {}",
             "  }",
             "",
             "  class D {",
             "    // BUG: Diagnostic contains:",
-            "    @Autowired D(String x) {}",
+            "    @Autowired",
+            "    D(String x) {}",
             "  }",
             "",
             "  class E {",
-            "    @Autowired E() {}",
+            "    @Autowired",
+            "    E() {}",
+            "",
             "    E(String x) {}",
             "  }",
             "",
             "  class F {",
             "    F() {}",
-            "    @Autowired F(String x) {}",
+            "",
+            "    @Autowired",
+            "    F(String x) {}",
             "  }",
             "",
             "  class G {",
@@ -55,7 +62,8 @@ public final class AutowiredConstructorCheckTest {
             "  }",
             "",
             "  class H {",
-            "    @SafeVarargs H(List<String>... lists) {}",
+            "    @SafeVarargs",
+            "    H(List<String>... lists) {}",
             "  }",
             "}")
         .doTest();
@@ -70,11 +78,14 @@ public final class AutowiredConstructorCheckTest {
             "",
             "interface Container {",
             "  class A {",
-            "    @Autowired @Deprecated A() {}",
+            "    @Autowired",
+            "    @Deprecated",
+            "    A() {}",
             "  }",
             "",
             "  class B {",
-            "    @Autowired B(String x) {}",
+            "    @Autowired",
+            "    B(String x) {}",
             "  }",
             "}")
         .addOutputLines(
@@ -83,10 +94,13 @@ public final class AutowiredConstructorCheckTest {
             "",
             "interface Container {",
             "  class A {",
-            "    @Deprecated A() {}",
+            "",
+            "    @Deprecated",
+            "    A() {}",
             "  }",
             "",
             "  class B {",
+            "",
             "    B(String x) {}",
             "  }",
             "}")

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

@@ -1,156 +0,0 @@
-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;
-
-public final class CanonicalAnnotationSyntaxCheckTest {
-  private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(CanonicalAnnotationSyntaxCheck.class, getClass());
-  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(CanonicalAnnotationSyntaxCheck.class, getClass());
-
-  @Test
-  void identification() {
-    compilationTestHelper
-        .addSourceLines(
-            "pkg/A.java",
-            "package pkg;",
-            "",
-            "import pkg.A.Foo;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    int[] value() default {};",
-            "    int[] value2() default {};",
-            "  }",
-            "",
-            "  @pkg.A.Foo A minimal1();",
-            "  @A.Foo A minimal2();",
-            "  @Foo A minimal3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo() A functional1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo() A functional2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo() A functional3();",
-            "",
-            "  @pkg.A.Foo(1) A simple1();",
-            "  @A.Foo(1) A simple2();",
-            "  @Foo(1) A simple3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo({1}) A singleton1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo({1}) A singleton2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({1}) A singleton3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo(value = 1) A verbose1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo(value = 1) A verbose2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(value = 1) A verbose3();",
-            "",
-            "  @pkg.A.Foo(value2 = 2) A custom1();",
-            "  @A.Foo(value2 = 2) A custom2();",
-            "  @Foo(value2 = 2) A custom3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo(value2 = {2}) A customSingleton1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo(value2 = {2}) A customSingleton2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(value2 = {2}) A customSingleton3();",
-            "",
-            "  @pkg.A.Foo(value2 = {2, 2}) A customPair1();",
-            "  @A.Foo(value2 = {2, 2}) A customPair2();",
-            "  @Foo(value2 = {2, 2}) A customPair3();",
-            "",
-            "  @pkg.A.Foo(value = 1, value2 = 2) A extended1();",
-            "  @A.Foo(value = 1, value2 = 2) A extended2();",
-            "  @Foo(value = 1, value2 = 2) A extended3();",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @pkg.A.Foo({1, 1,}) A trailingComma1();",
-            "  // BUG: Diagnostic contains:",
-            "  @A.Foo({1, 1,}) A trailingComma2();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({1, 1,}) A trailingComma3();",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void replacement() {
-    refactoringTestHelper
-        .addInputLines(
-            "in/pkg/A.java",
-            "package pkg;",
-            "",
-            "import pkg.A.Foo;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] value2() default {};",
-            "  }",
-            "",
-            "  @pkg.A.Foo() A functional1();",
-            "  @A.Foo() A functional2();",
-            "  @Foo() A functional3();",
-            "",
-            "  @pkg.A.Foo(value = \"foo\") A verbose1();",
-            "  @A.Foo(value = \"a'b\") A verbose2();",
-            "  @Foo(value = \"a\" + \"\\nb\") A verbose3();",
-            "",
-            "  @pkg.A.Foo(value = {\"foo\"}) A moreVerbose1();",
-            "  @A.Foo(value = {\"a'b\"}) A moreVerbose2();",
-            "  @Foo(value = {\"a\" + \"\\nb\"}) A moreVerbose3();",
-            "",
-            "  @pkg.A.Foo(value = {\"foo\", \"bar\"}, value2 = {2}) A extended1();",
-            "  @A.Foo(value = {\"a'b\", \"c'd\"}, value2 = {2}) A extended2();",
-            "  @Foo(value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"}, value2 = {2}) A extended3();",
-            "",
-            "  @pkg.A.Foo({\"foo\", \"bar\",}) A trailingComma1();",
-            "  @A.Foo({\"a'b\", \"c'd\",}) A trailingComma2();",
-            "  @Foo({\"a\" + \"\\nb\", \"c\" + \"\\nd\",}) A trailingComma3();",
-            "}")
-        .addOutputLines(
-            "out/pkg/A.java",
-            "package pkg;",
-            "",
-            "import pkg.A.Foo;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] value2() default {};",
-            "  }",
-            "",
-            "  @pkg.A.Foo A functional1();",
-            "  @A.Foo A functional2();",
-            "  @Foo A functional3();",
-            "",
-            "  @pkg.A.Foo(\"foo\") A verbose1();",
-            "  @A.Foo(\"a'b\") A verbose2();",
-            "  @Foo(\"a\" + \"\\nb\") A verbose3();",
-            "",
-            "  @pkg.A.Foo(\"foo\") A moreVerbose1();",
-            "  @A.Foo(\"a'b\") A moreVerbose2();",
-            "  @Foo(\"a\" + \"\\nb\") A moreVerbose3();",
-            "",
-            "  @pkg.A.Foo(value = {\"foo\", \"bar\"}, value2 = 2) A extended1();",
-            "  @A.Foo(value = {\"a'b\", \"c'd\"}, value2 = 2) A extended2();",
-            "  @Foo(value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"}, value2 = 2) A extended3();",
-            "",
-            "  @pkg.A.Foo({\"foo\", \"bar\"}) A trailingComma1();",
-            "  @A.Foo({\"a'b\", \"c'd\"}) A trailingComma2();",
-            "  @Foo({\"a\" + \"\\nb\", \"c\" + \"\\nd\"}) A trailingComma3();",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-}

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

@@ -0,0 +1,274 @@
+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 CanonicalAnnotationSyntaxTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(CanonicalAnnotationSyntax.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(CanonicalAnnotationSyntax.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "pkg/A.java",
+            "package pkg;",
+            "",
+            "import pkg.A.Foo;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    int[] value() default {};",
+            "",
+            "    int[] value2() default {};",
+            "  }",
+            "",
+            "  @pkg.A.Foo",
+            "  A minimal1();",
+            "",
+            "  @A.Foo",
+            "  A minimal2();",
+            "",
+            "  @Foo",
+            "  A minimal3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo()",
+            "  A functional1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo()",
+            "  A functional2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo()",
+            "  A functional3();",
+            "",
+            "  @pkg.A.Foo(1)",
+            "  A simple1();",
+            "",
+            "  @A.Foo(1)",
+            "  A simple2();",
+            "",
+            "  @Foo(1)",
+            "  A simple3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo({1})",
+            "  A singleton1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo({1})",
+            "  A singleton2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({1})",
+            "  A singleton3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo(value = 1)",
+            "  A verbose1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo(value = 1)",
+            "  A verbose2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(value = 1)",
+            "  A verbose3();",
+            "",
+            "  @pkg.A.Foo(value2 = 2)",
+            "  A custom1();",
+            "",
+            "  @A.Foo(value2 = 2)",
+            "  A custom2();",
+            "",
+            "  @Foo(value2 = 2)",
+            "  A custom3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo(value2 = {2})",
+            "  A customSingleton1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo(value2 = {2})",
+            "  A customSingleton2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(value2 = {2})",
+            "  A customSingleton3();",
+            "",
+            "  @pkg.A.Foo(value2 = {2, 2})",
+            "  A customPair1();",
+            "",
+            "  @A.Foo(value2 = {2, 2})",
+            "  A customPair2();",
+            "",
+            "  @Foo(value2 = {2, 2})",
+            "  A customPair3();",
+            "",
+            "  @pkg.A.Foo(value = 1, value2 = 2)",
+            "  A extended1();",
+            "",
+            "  @A.Foo(value = 1, value2 = 2)",
+            "  A extended2();",
+            "",
+            "  @Foo(value = 1, value2 = 2)",
+            "  A extended3();",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @pkg.A.Foo({",
+            "    1, 1,",
+            "  })",
+            "  A trailingComma1();",
+            "  // BUG: Diagnostic contains:",
+            "  @A.Foo({",
+            "    1, 1,",
+            "  })",
+            "  A trailingComma2();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({",
+            "    1, 1,",
+            "  })",
+            "  A trailingComma3();",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "in/pkg/A.java",
+            "package pkg;",
+            "",
+            "import pkg.A.Foo;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] value2() default {};",
+            "  }",
+            "",
+            "  @pkg.A.Foo()",
+            "  A functional1();",
+            "",
+            "  @A.Foo()",
+            "  A functional2();",
+            "",
+            "  @Foo()",
+            "  A functional3();",
+            "",
+            "  @pkg.A.Foo(value = \"foo\")",
+            "  A verbose1();",
+            "",
+            "  @A.Foo(value = \"a'b\")",
+            "  A verbose2();",
+            "",
+            "  @Foo(value = \"a\" + \"\\nb\")",
+            "  A verbose3();",
+            "",
+            "  @pkg.A.Foo(value = {\"foo\"})",
+            "  A moreVerbose1();",
+            "",
+            "  @A.Foo(value = {\"a'b\"})",
+            "  A moreVerbose2();",
+            "",
+            "  @Foo(value = {\"a\" + \"\\nb\"})",
+            "  A moreVerbose3();",
+            "",
+            "  @pkg.A.Foo(",
+            "      value = {\"foo\", \"bar\"},",
+            "      value2 = {2})",
+            "  A extended1();",
+            "",
+            "  @A.Foo(",
+            "      value = {\"a'b\", \"c'd\"},",
+            "      value2 = {2})",
+            "  A extended2();",
+            "",
+            "  @Foo(",
+            "      value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"},",
+            "      value2 = {2})",
+            "  A extended3();",
+            "",
+            "  @pkg.A.Foo({",
+            "    \"foo\", \"bar\",",
+            "  })",
+            "  A trailingComma1();",
+            "",
+            "  @A.Foo({",
+            "    \"a'b\", \"c'd\",",
+            "  })",
+            "  A trailingComma2();",
+            "",
+            "  @Foo({",
+            "    \"a\" + \"\\nb\",",
+            "    \"c\" + \"\\nd\",",
+            "  })",
+            "  A trailingComma3();",
+            "}")
+        .addOutputLines(
+            "out/pkg/A.java",
+            "package pkg;",
+            "",
+            "import pkg.A.Foo;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] value2() default {};",
+            "  }",
+            "",
+            "  @pkg.A.Foo",
+            "  A functional1();",
+            "",
+            "  @A.Foo",
+            "  A functional2();",
+            "",
+            "  @Foo",
+            "  A functional3();",
+            "",
+            "  @pkg.A.Foo(\"foo\")",
+            "  A verbose1();",
+            "",
+            "  @A.Foo(\"a'b\")",
+            "  A verbose2();",
+            "",
+            "  @Foo(\"a\" + \"\\nb\")",
+            "  A verbose3();",
+            "",
+            "  @pkg.A.Foo(\"foo\")",
+            "  A moreVerbose1();",
+            "",
+            "  @A.Foo(\"a'b\")",
+            "  A moreVerbose2();",
+            "",
+            "  @Foo(\"a\" + \"\\nb\")",
+            "  A moreVerbose3();",
+            "",
+            "  @pkg.A.Foo(",
+            "      value = {\"foo\", \"bar\"},",
+            "      value2 = 2)",
+            "  A extended1();",
+            "",
+            "  @A.Foo(",
+            "      value = {\"a'b\", \"c'd\"},",
+            "      value2 = 2)",
+            "  A extended2();",
+            "",
+            "  @Foo(",
+            "      value = {\"a\" + \"\\nb\", \"c\" + \"\\nd\"},",
+            "      value2 = 2)",
+            "  A extended3();",
+            "",
+            "  @pkg.A.Foo({\"foo\", \"bar\"})",
+            "  A trailingComma1();",
+            "",
+            "  @A.Foo({\"a'b\", \"c'd\"})",
+            "  A trailingComma2();",
+            "",
+            "  @Foo({\"a\" + \"\\nb\", \"c\" + \"\\nd\"})",
+            "  A trailingComma3();",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -0,0 +1,200 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers.SECOND;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class CollectorMutabilityTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(CollectorMutability.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(CollectorMutability.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "import static com.google.common.collect.ImmutableMap.toImmutableMap;",
+            "import static com.google.common.collect.ImmutableSet.toImmutableSet;",
+            "import static java.util.stream.Collectors.toCollection;",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.ArrayList;",
+            "import java.util.HashMap;",
+            "import java.util.HashSet;",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collect(Collectors.toList());",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(2).collect(toList());",
+            "    Flux.just(3).collect(toImmutableList());",
+            "    Flux.just(4).collect(toCollection(ArrayList::new));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(\"foo\").collect(Collectors.toMap(String::getBytes, String::length));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(\"bar\").collect(toMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(toImmutableMap(String::getBytes, String::length));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> a));",
+            "    Flux.just(\"quux\").collect(toImmutableMap(String::getBytes, String::length, (a, b) -> a));",
+            "    Flux.just(\"quuz\").collect(toMap(String::getBytes, String::length, (a, b) -> a, HashMap::new));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Stream.of(1).collect(Collectors.toSet());",
+            "    // BUG: Diagnostic contains:",
+            "    Stream.of(2).collect(toSet());",
+            "    Stream.of(3).collect(toImmutableSet());",
+            "    Stream.of(4).collect(toCollection(HashSet::new));",
+            "",
+            "    Flux.just(\"foo\").collect(Collectors.joining());",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacementFirstSuggestedFix() {
+    refactoringTestHelper
+        .addInputLines(
+            "A.java",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(Collectors.toList());",
+            "    Flux.just(2).collect(toList());",
+            "",
+            "    Stream.of(\"foo\").collect(Collectors.toMap(String::getBytes, String::length));",
+            "    Stream.of(\"bar\").collect(toMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(Collectors.toMap(String::getBytes, String::length, (a, b) -> b));",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> b));",
+            "",
+            "    Stream.of(1).collect(Collectors.toSet());",
+            "    Stream.of(2).collect(toSet());",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "import static com.google.common.collect.ImmutableMap.toImmutableMap;",
+            "import static com.google.common.collect.ImmutableSet.toImmutableSet;",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toImmutableList());",
+            "    Flux.just(2).collect(toImmutableList());",
+            "",
+            "    Stream.of(\"foo\").collect(toImmutableMap(String::getBytes, String::length));",
+            "    Stream.of(\"bar\").collect(toImmutableMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(toImmutableMap(String::getBytes, String::length, (a, b) -> b));",
+            "    Flux.just(\"qux\").collect(toImmutableMap(String::getBytes, String::length, (a, b) -> b));",
+            "",
+            "    Stream.of(1).collect(toImmutableSet());",
+            "    Stream.of(2).collect(toImmutableSet());",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+
+  @Test
+  void replacementSecondSuggestedFix() {
+    refactoringTestHelper
+        .setFixChooser(SECOND)
+        .addInputLines(
+            "A.java",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(Collectors.toList());",
+            "    Flux.just(2).collect(toList());",
+            "",
+            "    Stream.of(\"foo\").collect(Collectors.toMap(String::getBytes, String::length));",
+            "    Stream.of(\"bar\").collect(toMap(String::getBytes, String::length));",
+            "    Flux.just(\"baz\").collect(Collectors.toMap(String::getBytes, String::length, (a, b) -> b));",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> b));",
+            "",
+            "    Stream.of(1).collect(Collectors.toSet());",
+            "    Stream.of(2).collect(toSet());",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static java.util.stream.Collectors.toCollection;",
+            "import static java.util.stream.Collectors.toList;",
+            "import static java.util.stream.Collectors.toMap;",
+            "import static java.util.stream.Collectors.toSet;",
+            "",
+            "import java.util.ArrayList;",
+            "import java.util.HashMap;",
+            "import java.util.HashSet;",
+            "import java.util.stream.Collectors;",
+            "import java.util.stream.Stream;",
+            "import reactor.core.publisher.Flux;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toCollection(ArrayList::new));",
+            "    Flux.just(2).collect(toCollection(ArrayList::new));",
+            "",
+            "    Stream.of(\"foo\")",
+            "        .collect(",
+            "            Collectors.toMap(",
+            "                String::getBytes,",
+            "                String::length,",
+            "                (a, b) -> {",
+            "                  throw new IllegalStateException();",
+            "                },",
+            "                HashMap::new));",
+            "    Stream.of(\"bar\")",
+            "        .collect(",
+            "            toMap(",
+            "                String::getBytes,",
+            "                String::length,",
+            "                (a, b) -> {",
+            "                  throw new IllegalStateException();",
+            "                },",
+            "                HashMap::new));",
+            "    Flux.just(\"baz\")",
+            "        .collect(Collectors.toMap(String::getBytes, String::length, (a, b) -> b, HashMap::new));",
+            "    Flux.just(\"qux\").collect(toMap(String::getBytes, String::length, (a, b) -> b, HashMap::new));",
+            "",
+            "    Stream.of(1).collect(toCollection(HashSet::new));",
+            "    Stream.of(2).collect(toCollection(HashSet::new));",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class EmptyMethodCheckTest {
+final class EmptyMethodTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(EmptyMethodCheck.class, getClass());
+      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(EmptyMethodCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());
 
   @Test
   void identification() {

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

@@ -0,0 +1,151 @@
+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 ErrorProneTestHelperSourceFormatTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(ErrorProneTestHelperSourceFormat.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(
+          ErrorProneTestHelperSourceFormat.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import tech.picnic.errorprone.bugpatterns.EmptyMethod;",
+            "",
+            "class A {",
+            "  private final CompilationTestHelper compilationTestHelper =",
+            "      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "  private final BugCheckerRefactoringTestHelper refactoringTestHelper =",
+            "      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "",
+            "  void m() {",
+            "    compilationTestHelper",
+            "        // BUG: Diagnostic contains: No source code provided",
+            "        .addSourceLines(\"A.java\")",
+            "        // BUG: Diagnostic contains: Source code is malformed:",
+            "        .addSourceLines(\"B.java\", \"class B {\")",
+            "        // Well-formed code, so not flagged.",
+            "        .addSourceLines(\"C.java\", \"class C {}\")",
+            "        // Malformed code, but not compile-time constant, so not flagged.",
+            "        .addSourceLines(\"D.java\", \"class D {\" + getClass())",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addSourceLines(\"E.java\", \"class E { }\")",
+            "        .doTest();",
+            "",
+            "    refactoringTestHelper",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addInputLines(\"in/A.java\", \"class A { }\")",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addOutputLines(\"out/A.java\", \"class A { }\")",
+            "        // BUG: Diagnostic contains: Test code should follow the Google Java style",
+            "        .addInputLines(\"in/B.java\", \"import java.util.Map;\", \"\", \"class B {}\")",
+            "        // Unused import, but in an output file, so not flagged.",
+            "        .addOutputLines(\"out/B.java\", \"import java.util.Map;\", \"\", \"class B {}\")",
+            "        .doTest(TestMode.TEXT_MATCH);",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    /*
+     * Verifies that import sorting and code formatting is performed unconditionally, while unused
+     * imports are removed unless part of a `BugCheckerRefactoringTestHelper` expected output file.
+     */
+    refactoringTestHelper
+        .addInputLines(
+            "in/A.java",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import tech.picnic.errorprone.bugpatterns.EmptyMethod;",
+            "",
+            "class A {",
+            "  private final CompilationTestHelper compilationTestHelper =",
+            "      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "  private final BugCheckerRefactoringTestHelper refactoringTestHelper =",
+            "      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "",
+            "  void m() {",
+            "    compilationTestHelper",
+            "        .addSourceLines(",
+            "            \"A.java\",",
+            "            \"import java.util.Map;\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A,A> { }\")",
+            "        .doTest();",
+            "",
+            "    refactoringTestHelper",
+            "        .addInputLines(",
+            "            \"in/A.java\",",
+            "            \"import java.util.Map;\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A,A> { }\")",
+            "        .addOutputLines(",
+            "            \"out/A.java\",",
+            "            \"import java.util.Map;\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A,A> { }\")",
+            "        .doTest(TestMode.TEXT_MATCH);",
+            "  }",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper;",
+            "import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;",
+            "import com.google.errorprone.CompilationTestHelper;",
+            "import tech.picnic.errorprone.bugpatterns.EmptyMethod;",
+            "",
+            "class A {",
+            "  private final CompilationTestHelper compilationTestHelper =",
+            "      CompilationTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "  private final BugCheckerRefactoringTestHelper refactoringTestHelper =",
+            "      BugCheckerRefactoringTestHelper.newInstance(EmptyMethod.class, getClass());",
+            "",
+            "  void m() {",
+            "    compilationTestHelper",
+            "        .addSourceLines(",
+            "            \"A.java\",",
+            "            \"import java.util.List;\",",
+            "            \"import java.util.Map;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A, A> {}\")",
+            "        .doTest();",
+            "",
+            "    refactoringTestHelper",
+            "        .addInputLines(",
+            "            \"in/A.java\",",
+            "            \"import java.util.List;\",",
+            "            \"import java.util.Map;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A, A> {}\")",
+            "        .addOutputLines(",
+            "            \"out/A.java\",",
+            "            \"import java.util.Collection;\",",
+            "            \"import java.util.List;\",",
+            "            \"import java.util.Map;\",",
+            "            \"\",",
+            "            \"interface A extends List<A>, Map<A, A> {}\")",
+            "        .doTest(TestMode.TEXT_MATCH);",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -3,23 +3,23 @@ package tech.picnic.errorprone.bugpatterns;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-final class ExplicitEnumOrderingCheckTest {
+final class ExplicitEnumOrderingTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(ExplicitEnumOrderingCheck.class, getClass());
+      CompilationTestHelper.newInstance(ExplicitEnumOrdering.class, getClass());
 
   @Test
-  void Identification() {
+  void identification() {
     compilationTestHelper
         .addSourceLines(
             "A.java",
-            "import static java.lang.annotation.RetentionPolicy.SOURCE;",
             "import static java.lang.annotation.RetentionPolicy.CLASS;",
             "import static java.lang.annotation.RetentionPolicy.RUNTIME;",
+            "import static java.lang.annotation.RetentionPolicy.SOURCE;",
             "import static java.time.chrono.IsoEra.BCE;",
             "import static java.time.chrono.IsoEra.CE;",
             "",
-            "import com.google.common.collect.Ordering;",
             "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.Ordering;",
             "import java.lang.annotation.RetentionPolicy;",
             "import java.time.chrono.IsoEra;",
             "",

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

@@ -7,11 +7,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-final class FluxFlatMapUsageCheckTest {
+final class FluxFlatMapUsageTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(FluxFlatMapUsageCheck.class, getClass());
+      CompilationTestHelper.newInstance(FluxFlatMapUsage.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      newInstance(FluxFlatMapUsageCheck.class, getClass());
+      newInstance(FluxFlatMapUsage.class, getClass());
 
   @Test
   void identification() {
@@ -20,8 +20,8 @@ final class FluxFlatMapUsageCheckTest {
             "A.java",
             "import java.util.function.BiFunction;",
             "import java.util.function.Function;",
-            "import reactor.core.publisher.Mono;",
             "import reactor.core.publisher.Flux;",
+            "import reactor.core.publisher.Mono;",
             "",
             "class A {",
             "  void m() {",

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

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class FormatStringConcatenationCheckTest {
+final class FormatStringConcatenationTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(FormatStringConcatenationCheck.class, getClass());
+      CompilationTestHelper.newInstance(FormatStringConcatenation.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(FormatStringConcatenationCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(FormatStringConcatenation.class, getClass());
 
   @Test
   void identification() {
@@ -23,8 +23,8 @@ public final class FormatStringConcatenationCheckTest {
             "import static org.assertj.core.api.Assertions.assertThat;",
             "import static org.assertj.core.api.SoftAssertions.assertSoftly;",
             "",
-            "import java.util.Locale;",
             "import java.util.Formatter;",
+            "import java.util.Locale;",
             "import org.assertj.core.api.Assertions;",
             "import org.assertj.core.api.BDDAssertions;",
             "import org.assertj.core.api.Fail;",
@@ -269,9 +269,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.error(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.error((Marker) null,\"str \" + toString());",
+            "    LOG.error((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.error((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.error((Marker) null, \"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
             "    LOG.info(\"str \" + toString());",
@@ -279,9 +279,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.info(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.info((Marker) null,\"str \" + toString());",
+            "    LOG.info((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.info((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.info((Marker) null, \"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
             "    LOG.trace(\"str \" + toString());",
@@ -289,9 +289,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.trace(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.trace((Marker) null,\"str \" + toString());",
+            "    LOG.trace((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.trace((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.trace((Marker) null, \"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
             "    LOG.warn(\"str \" + toString());",
@@ -299,9 +299,9 @@ public final class FormatStringConcatenationCheckTest {
             "    LOG.warn(\"{} \" + toString(), \"arg\");",
             "",
             "    // BUG: Diagnostic contains:",
-            "    LOG.warn((Marker) null,\"str \" + toString());",
+            "    LOG.warn((Marker) null, \"str \" + toString());",
             "    // BUG: Diagnostic contains:",
-            "    LOG.warn((Marker) null,\"{} \" + toString(), \"arg\");",
+            "    LOG.warn((Marker) null, \"{} \" + toString(), \"arg\");",
             "  }",
             "}")
         .doTest();
@@ -316,7 +316,6 @@ public final class FormatStringConcatenationCheckTest {
             "import static org.assertj.core.api.Assertions.assertThat;",
             "",
             "import java.util.Locale;",
-            "import java.util.Formatter;",
             "import org.slf4j.Logger;",
             "import org.slf4j.LoggerFactory;",
             "import org.slf4j.Marker;",
@@ -366,7 +365,6 @@ public final class FormatStringConcatenationCheckTest {
             "import static org.assertj.core.api.Assertions.assertThat;",
             "",
             "import java.util.Locale;",
-            "import java.util.Formatter;",
             "import org.slf4j.Logger;",
             "import org.slf4j.LoggerFactory;",
             "import org.slf4j.Marker;",
@@ -400,6 +398,7 @@ public final class FormatStringConcatenationCheckTest {
             "    String.format(\"{} \" + toString(), \"arg\");",
             "    String.format(Locale.ROOT, \"{} \" + toString(), \"arg\");",
             "  }",
+            "",
             "  void slf4j() {",
             "    LOG.debug(\"str {}\", toString());",
             "    LOG.debug((Marker) null, \"str {}\", toString());",

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

@@ -6,11 +6,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-final class IdentityConversionCheckTest {
+final class IdentityConversionTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(IdentityConversionCheck.class, getClass());
+      CompilationTestHelper.newInstance(IdentityConversion.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(IdentityConversionCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(IdentityConversion.class, getClass());
 
   @Test
   void identification() {
@@ -121,8 +121,9 @@ final class IdentityConversionCheckTest {
             "    ImmutableBiMap<Object, Object> o1 = ImmutableBiMap.copyOf(ImmutableBiMap.of());",
             "    // BUG: Diagnostic contains:",
             "    ImmutableList<Object> o2 = ImmutableList.copyOf(ImmutableList.of());",
-            "    // BUG: Diagnostic contains:",
-            "    ImmutableListMultimap<Object, Object> o3 = ImmutableListMultimap.copyOf(ImmutableListMultimap.of());",
+            "    ImmutableListMultimap<Object, Object> o3 =",
+            "        // BUG: Diagnostic contains:",
+            "        ImmutableListMultimap.copyOf(ImmutableListMultimap.of());",
             "    // BUG: Diagnostic contains:",
             "    ImmutableMap<Object, Object> o4 = ImmutableMap.copyOf(ImmutableMap.of());",
             "    // BUG: Diagnostic contains:",
@@ -135,8 +136,9 @@ final class IdentityConversionCheckTest {
             "    ImmutableRangeSet<String> o8 = ImmutableRangeSet.copyOf(ImmutableRangeSet.of());",
             "    // BUG: Diagnostic contains:",
             "    ImmutableSet<Object> o9 = ImmutableSet.copyOf(ImmutableSet.of());",
-            "    // BUG: Diagnostic contains:",
-            "    ImmutableSetMultimap<Object, Object> o10 = ImmutableSetMultimap.copyOf(ImmutableSetMultimap.of());",
+            "    ImmutableSetMultimap<Object, Object> o10 =",
+            "        // BUG: Diagnostic contains:",
+            "        ImmutableSetMultimap.copyOf(ImmutableSetMultimap.of());",
             "    // BUG: Diagnostic contains:",
             "    ImmutableTable<Object, Object, Object> o11 = ImmutableTable.copyOf(ImmutableTable.of());",
             "",
@@ -171,8 +173,8 @@ final class IdentityConversionCheckTest {
             "import com.google.common.collect.ImmutableCollection;",
             "import com.google.common.collect.ImmutableList;",
             "import com.google.common.collect.ImmutableSet;",
-            "import java.util.Collection;",
             "import java.util.ArrayList;",
+            "import java.util.Collection;",
             "import org.reactivestreams.Publisher;",
             "import reactor.adapter.rxjava.RxJava2Adapter;",
             "import reactor.core.publisher.Flux;",
@@ -204,8 +206,7 @@ final class IdentityConversionCheckTest {
             "    Object o1 = ImmutableSet.copyOf(ImmutableList.of());",
             "    Object o2 = ImmutableSet.copyOf(ImmutableSet.of());",
             "",
-            "    when(\"foo\".contains(\"f\"))",
-            "        .thenAnswer(inv-> ImmutableSet.copyOf(ImmutableList.of(1)));",
+            "    when(\"foo\".contains(\"f\")).thenAnswer(inv -> ImmutableSet.copyOf(ImmutableList.of(1)));",
             "  }",
             "",
             "  void bar(Publisher<Integer> publisher) {}",
@@ -217,8 +218,8 @@ final class IdentityConversionCheckTest {
             "import com.google.common.collect.ImmutableCollection;",
             "import com.google.common.collect.ImmutableList;",
             "import com.google.common.collect.ImmutableSet;",
-            "import java.util.Collection;",
             "import java.util.ArrayList;",
+            "import java.util.Collection;",
             "import org.reactivestreams.Publisher;",
             "import reactor.adapter.rxjava.RxJava2Adapter;",
             "import reactor.core.publisher.Flux;",
@@ -250,8 +251,7 @@ final class IdentityConversionCheckTest {
             "    Object o1 = ImmutableSet.copyOf(ImmutableList.of());",
             "    Object o2 = ImmutableSet.of();",
             "",
-            "    when(\"foo\".contains(\"f\"))",
-            "        .thenAnswer(inv-> ImmutableSet.copyOf(ImmutableList.of(1)));",
+            "    when(\"foo\".contains(\"f\")).thenAnswer(inv -> ImmutableSet.copyOf(ImmutableList.of(1)));",
             "  }",
             "",
             "  void bar(Publisher<Integer> publisher) {}",
@@ -269,9 +269,6 @@ final class IdentityConversionCheckTest {
             "import com.google.common.collect.ImmutableList;",
             "import com.google.common.collect.ImmutableSet;",
             "import java.util.ArrayList;",
-            "import reactor.adapter.rxjava.RxJava2Adapter;",
-            "import reactor.core.publisher.Flux;",
-            "import reactor.core.publisher.Mono;",
             "",
             "public final class Foo {",
             "  public void foo() {",
@@ -288,9 +285,6 @@ final class IdentityConversionCheckTest {
             "import com.google.common.collect.ImmutableList;",
             "import com.google.common.collect.ImmutableSet;",
             "import java.util.ArrayList;",
-            "import reactor.adapter.rxjava.RxJava2Adapter;",
-            "import reactor.core.publisher.Flux;",
-            "import reactor.core.publisher.Mono;",
             "",
             "public final class Foo {",
             "  public void foo() {",

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

@@ -0,0 +1,182 @@
+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 ImmutablesSortedSetComparatorTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(ImmutablesSortedSetComparator.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(ImmutablesSortedSetComparator.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import com.google.common.collect.ContiguousSet;",
+            "import com.google.common.collect.ImmutableSet;",
+            "import com.google.common.collect.ImmutableSortedSet;",
+            "import java.util.NavigableSet;",
+            "import java.util.Set;",
+            "import java.util.SortedSet;",
+            "import java.util.TreeSet;",
+            "import org.immutables.value.Value;",
+            "",
+            "interface A {",
+            "  @Value.Immutable",
+            "  interface ImmutableInterface {",
+            "    Set<String> set();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    SortedSet<String> sortedSet();",
+            "",
+            "    @Value.NaturalOrder",
+            "    SortedSet<String> sortedSet2();",
+            "  }",
+            "",
+            "  @Value.Modifiable",
+            "  interface ModifiableInterfaceWithDefaults {",
+            "    @Value.Default",
+            "    default Set<Integer> set() {",
+            "      return new TreeSet<>();",
+            "    }",
+            "",
+            "    @Value.Default",
+            "    // BUG: Diagnostic contains:",
+            "    default NavigableSet<Integer> navigableSet() {",
+            "      return new TreeSet<>();",
+            "    }",
+            "",
+            "    @Value.Default",
+            "    @Value.ReverseOrder",
+            "    default NavigableSet<Integer> navigableSet2() {",
+            "      return new TreeSet<>();",
+            "    }",
+            "",
+            "    default NavigableSet<Integer> nonPropertyNavigableSet() {",
+            "      return new TreeSet<>();",
+            "    }",
+            "  }",
+            "",
+            "  interface NonImmutablesInterface {",
+            "    SortedSet<String> sortedSet();",
+            "  }",
+            "",
+            "  @Value.Immutable",
+            "  abstract class AbstractImmutableWithDefaults {",
+            "    @Value.Default",
+            "    ImmutableSet<Integer> immutableSet() {",
+            "      return ImmutableSet.of();",
+            "    }",
+            "",
+            "    @Value.Default",
+            "    // BUG: Diagnostic contains:",
+            "    ImmutableSortedSet<String> immutableSortedSet() {",
+            "      return ImmutableSortedSet.of();",
+            "    }",
+            "",
+            "    @Value.Default",
+            "    @Value.NaturalOrder",
+            "    ImmutableSortedSet<String> immutableSortedSet2() {",
+            "      return ImmutableSortedSet.of();",
+            "    }",
+            "",
+            "    ImmutableSortedSet<String> nonPropertyImmutableSortedSet() {",
+            "      return ImmutableSortedSet.of();",
+            "    }",
+            "  }",
+            "",
+            "  @Value.Modifiable",
+            "  abstract class AbstractModifiable {",
+            "    abstract ImmutableSet<Integer> immutableSet();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    abstract ContiguousSet<Integer> contiguousSet();",
+            "",
+            "    @Value.ReverseOrder",
+            "    abstract ContiguousSet<Integer> contiguousSet2();",
+            "  }",
+            "",
+            "  abstract class AbstractNonImmutables {",
+            "    abstract SortedSet<Integer> sortedSet();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "A.java",
+            "import com.google.common.collect.ImmutableSortedSet;",
+            "import java.util.SortedSet;",
+            "import org.immutables.value.Value;",
+            "",
+            "@Value.Immutable",
+            "abstract class A {",
+            "  abstract ImmutableSortedSet<String> sortedSet();",
+            "",
+            "  @Value.Modifiable",
+            "  interface B {",
+            "    SortedSet<String> sortedSet();",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import com.google.common.collect.ImmutableSortedSet;",
+            "import java.util.SortedSet;",
+            "import org.immutables.value.Value;",
+            "",
+            "@Value.Immutable",
+            "abstract class A {",
+            "  @Value.NaturalOrder",
+            "  abstract ImmutableSortedSet<String> sortedSet();",
+            "",
+            "  @Value.Modifiable",
+            "  interface B {",
+            "    @Value.NaturalOrder",
+            "    SortedSet<String> sortedSet();",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+
+  @Test
+  void replacementWithImportClash() {
+    refactoringTestHelper
+        .addInputLines(
+            "MySpringService.java",
+            "import com.google.common.collect.ImmutableSortedSet;",
+            "import org.springframework.beans.factory.annotation.Value;",
+            "",
+            "class MySpringService {",
+            "  MySpringService(@Value(\"${someProperty}\") String prop) {}",
+            "  ;",
+            "",
+            "  @org.immutables.value.Value.Immutable",
+            "  interface A {",
+            "    ImmutableSortedSet<String> sortedSet();",
+            "  }",
+            "}")
+        .addOutputLines(
+            "MySpringService.java",
+            "import com.google.common.collect.ImmutableSortedSet;",
+            "import org.springframework.beans.factory.annotation.Value;",
+            "",
+            "class MySpringService {",
+            "  MySpringService(@Value(\"${someProperty}\") String prop) {}",
+            "  ;",
+            "",
+            "  @org.immutables.value.Value.Immutable",
+            "  interface A {",
+            "    @org.immutables.value.Value.NaturalOrder",
+            "    ImmutableSortedSet<String> sortedSet();",
+            "  }",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -1,224 +0,0 @@
-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 JUnitMethodDeclarationCheckTest {
-  private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(JUnitMethodDeclarationCheck.class, getClass());
-  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(JUnitMethodDeclarationCheck.class, getClass());
-
-  @Test
-  void identification() {
-    compilationTestHelper
-        .addSourceLines(
-            "A.java",
-            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
-            "",
-            "import org.junit.jupiter.api.AfterAll;",
-            "import org.junit.jupiter.api.AfterEach;",
-            "import org.junit.jupiter.api.BeforeAll;",
-            "import org.junit.jupiter.api.BeforeEach;",
-            "import org.junit.jupiter.api.Test;",
-            "import org.junit.jupiter.params.ParameterizedTest;",
-            "",
-            "class A {",
-            "  @BeforeAll void setUp1() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @BeforeAll public void setUp2() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @BeforeAll protected void setUp3() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @BeforeAll private void setUp4() {}",
-            "",
-            "  @BeforeEach void setup5() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @BeforeEach public void setUp6() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @BeforeEach protected void setUp7() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @BeforeEach private void setUp8() {}",
-            "",
-            "  @AfterEach void tearDown1() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @AfterEach public void tearDown2() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @AfterEach protected void tearDown3() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @AfterEach private void tearDown4() {}",
-            "",
-            "  @AfterAll void tearDown5() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @AfterAll public void tearDown6() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @AfterAll protected void tearDown7() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @AfterAll private void tearDown8() {}",
-            "",
-            "  @Test void method1() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @Test void testMethod2() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @Test public void method3() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @Test protected void method4() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @Test private void method5() {}",
-            "",
-            "  @ParameterizedTest void method6() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @ParameterizedTest void testMethod7() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @ParameterizedTest public void method8() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @ParameterizedTest protected void method9() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @ParameterizedTest private void method10() {}",
-            "",
-            "  @BeforeEach @BeforeAll @AfterEach @AfterAll void testNonTestMethod1() {}",
-            "  public void testNonTestMethod2() {}",
-            "  protected void testNonTestMethod3() {}",
-            "  private void testNonTestMethod4() {}",
-            "  @Test void test5() {}",
-            "",
-            "  // BUG: Diagnostic contains: (but note that a method named `overload` already exists in this class)",
-            "  @Test void testOverload() {}",
-            "  void overload() {}",
-            "  // BUG: Diagnostic contains: (but note that `arguments` is already statically imported)",
-            "  @Test void testArguments() {}",
-            "  // BUG: Diagnostic contains: (but note that `public` is a reserved keyword)",
-            "  @Test void testPublic() {}",
-            "}")
-        .addSourceLines(
-            "B.java",
-            "import org.junit.jupiter.api.AfterAll;",
-            "import org.junit.jupiter.api.AfterEach;",
-            "import org.junit.jupiter.api.BeforeAll;",
-            "import org.junit.jupiter.api.BeforeEach;",
-            "import org.junit.jupiter.api.Test;",
-            "import org.junit.jupiter.params.ParameterizedTest;",
-            "",
-            "class B extends A {",
-            "  @Override @BeforeAll void setUp1() {}",
-            "  @Override @BeforeAll public void setUp2() {}",
-            "  @Override @BeforeAll protected void setUp3() {}",
-            "",
-            "  @Override @BeforeEach void setup5() {}",
-            "  @Override @BeforeEach public void setUp6() {}",
-            "  @Override @BeforeEach protected void setUp7() {}",
-            "",
-            "  @Override @AfterEach void tearDown1() {}",
-            "  @Override @AfterEach public void tearDown2() {}",
-            "  @Override @AfterEach protected void tearDown3() {}",
-            "",
-            "  @Override @AfterAll void tearDown5() {}",
-            "  @Override @AfterAll public void tearDown6() {}",
-            "  @Override @AfterAll protected void tearDown7() {}",
-            "",
-            "  @Override @Test void method1() {}",
-            "  @Override @Test void testMethod2() {}",
-            "  @Override @Test public void method3() {}",
-            "  @Override @Test protected void method4() {}",
-            "",
-            "  @Override @ParameterizedTest void method6() {}",
-            "  @Override @ParameterizedTest void testMethod7() {}",
-            "  @Override @ParameterizedTest public void method8() {}",
-            "  @Override @ParameterizedTest protected void method9() {}",
-            "",
-            "  @Override @BeforeEach @BeforeAll @AfterEach @AfterAll void testNonTestMethod1() {}",
-            "  @Override public void testNonTestMethod2() {}",
-            "  @Override protected void testNonTestMethod3() {}",
-            "  @Override @Test void test5() {}",
-            "",
-            "  @Override @Test void testOverload() {}",
-            "  @Override void overload() {}",
-            "  @Override @Test void testArguments() {}",
-            "  @Override @Test void testPublic() {}",
-            "}")
-        .addSourceLines(
-            "C.java",
-            "import org.junit.jupiter.api.AfterAll;",
-            "import org.junit.jupiter.api.BeforeAll;",
-            "import org.junit.jupiter.api.Test;",
-            "",
-            "abstract class C {",
-            "  @BeforeAll public void setUp() {}",
-            "  @Test void testMethod1() {}",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @AfterAll private void tearDown() {}",
-            "  // BUG: Diagnostic contains:",
-            "  @Test final void testMethod2() {}",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void replacement() {
-    refactoringTestHelper
-        .addInputLines(
-            "in/A.java",
-            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
-            "",
-            "import org.junit.jupiter.api.AfterAll;",
-            "import org.junit.jupiter.api.AfterEach;",
-            "import org.junit.jupiter.api.BeforeAll;",
-            "import org.junit.jupiter.api.BeforeEach;",
-            "import org.junit.jupiter.api.RepeatedTest;",
-            "import org.junit.jupiter.api.Test;",
-            "import org.junit.jupiter.params.ParameterizedTest;",
-            "",
-            "class A {",
-            "  @BeforeAll public void setUp1() {}",
-            "  @BeforeEach protected void setUp2() {}",
-            "  @AfterEach private void setUp3() {}",
-            "  @AfterAll private void setUp4() {}",
-            "",
-            "  @Test void testFoo() {}",
-            "  @ParameterizedTest void testBar() {}",
-            "",
-            "  @Test public void baz() {}",
-            "  @RepeatedTest(2) private void qux() {}",
-            "  @ParameterizedTest protected void quux() {}",
-            "",
-            "  @Test public void testOverload() {}",
-            "  void overload() {}",
-            "  @Test protected void testArguments() {}",
-            "  @Test private void testClass() {}",
-            "}")
-        .addOutputLines(
-            "out/A.java",
-            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
-            "",
-            "import org.junit.jupiter.api.AfterAll;",
-            "import org.junit.jupiter.api.AfterEach;",
-            "import org.junit.jupiter.api.BeforeAll;",
-            "import org.junit.jupiter.api.BeforeEach;",
-            "import org.junit.jupiter.api.RepeatedTest;",
-            "import org.junit.jupiter.api.Test;",
-            "import org.junit.jupiter.params.ParameterizedTest;",
-            "",
-            "class A {",
-            "  @BeforeAll void setUp1() {}",
-            "  @BeforeEach void setUp2() {}",
-            "  @AfterEach void setUp3() {}",
-            "  @AfterAll void setUp4() {}",
-            "",
-            "  @Test void foo() {}",
-            "  @ParameterizedTest void bar() {}",
-            "",
-            "  @Test void baz() {}",
-            "  @RepeatedTest(2) void qux() {}",
-            "  @ParameterizedTest void quux() {}",
-            "",
-            "  @Test void testOverload() {}",
-            "  void overload() {}",
-            "  @Test void testArguments() {}",
-            "  @Test void testClass() {}",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-}

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

@@ -0,0 +1,422 @@
+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 JUnitMethodDeclarationTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(JUnitMethodDeclaration.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(JUnitMethodDeclaration.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
+            "",
+            "import org.junit.jupiter.api.AfterAll;",
+            "import org.junit.jupiter.api.AfterEach;",
+            "import org.junit.jupiter.api.BeforeAll;",
+            "import org.junit.jupiter.api.BeforeEach;",
+            "import org.junit.jupiter.api.Test;",
+            "import org.junit.jupiter.params.ParameterizedTest;",
+            "",
+            "class A {",
+            "  {",
+            "    arguments();",
+            "  }",
+            "",
+            "  @BeforeAll",
+            "  void setUp1() {}",
+            "",
+            "  @BeforeAll",
+            "  // BUG: Diagnostic contains:",
+            "  public void setUp2() {}",
+            "",
+            "  @BeforeAll",
+            "  // BUG: Diagnostic contains:",
+            "  protected void setUp3() {}",
+            "",
+            "  @BeforeAll",
+            "  // BUG: Diagnostic contains:",
+            "  private void setUp4() {}",
+            "",
+            "  @BeforeEach",
+            "  void setup5() {}",
+            "",
+            "  @BeforeEach",
+            "  // BUG: Diagnostic contains:",
+            "  public void setUp6() {}",
+            "",
+            "  @BeforeEach",
+            "  // BUG: Diagnostic contains:",
+            "  protected void setUp7() {}",
+            "",
+            "  @BeforeEach",
+            "  // BUG: Diagnostic contains:",
+            "  private void setUp8() {}",
+            "",
+            "  @AfterEach",
+            "  void tearDown1() {}",
+            "",
+            "  @AfterEach",
+            "  // BUG: Diagnostic contains:",
+            "  public void tearDown2() {}",
+            "",
+            "  @AfterEach",
+            "  // BUG: Diagnostic contains:",
+            "  protected void tearDown3() {}",
+            "",
+            "  @AfterEach",
+            "  // BUG: Diagnostic contains:",
+            "  private void tearDown4() {}",
+            "",
+            "  @AfterAll",
+            "  void tearDown5() {}",
+            "",
+            "  @AfterAll",
+            "  // BUG: Diagnostic contains:",
+            "  public void tearDown6() {}",
+            "",
+            "  @AfterAll",
+            "  // BUG: Diagnostic contains:",
+            "  protected void tearDown7() {}",
+            "",
+            "  @AfterAll",
+            "  // BUG: Diagnostic contains:",
+            "  private void tearDown8() {}",
+            "",
+            "  @Test",
+            "  void method1() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains:",
+            "  void testMethod2() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains:",
+            "  public void method3() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains:",
+            "  protected void method4() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains:",
+            "  private void method5() {}",
+            "",
+            "  @ParameterizedTest",
+            "  void method6() {}",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  void testMethod7() {}",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  public void method8() {}",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  protected void method9() {}",
+            "",
+            "  @ParameterizedTest",
+            "  // BUG: Diagnostic contains:",
+            "  private void method10() {}",
+            "",
+            "  @BeforeEach",
+            "  @BeforeAll",
+            "  @AfterEach",
+            "  @AfterAll",
+            "  void testNonTestMethod1() {}",
+            "",
+            "  public void testNonTestMethod2() {}",
+            "",
+            "  protected void testNonTestMethod3() {}",
+            "",
+            "  private void testNonTestMethod4() {}",
+            "",
+            "  @Test",
+            "  void test5() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains: (but note that a method named `overload` already exists in this",
+            "  // class)",
+            "  void testOverload() {}",
+            "",
+            "  void overload() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains: (but note that `arguments` is already statically imported)",
+            "  void testArguments() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains: (but note that `public` is a reserved keyword)",
+            "  void testPublic() {}",
+            "}")
+        .addSourceLines(
+            "B.java",
+            "import org.junit.jupiter.api.AfterAll;",
+            "import org.junit.jupiter.api.AfterEach;",
+            "import org.junit.jupiter.api.BeforeAll;",
+            "import org.junit.jupiter.api.BeforeEach;",
+            "import org.junit.jupiter.api.Test;",
+            "import org.junit.jupiter.params.ParameterizedTest;",
+            "",
+            "class B extends A {",
+            "  @Override",
+            "  @BeforeAll",
+            "  void setUp1() {}",
+            "",
+            "  @Override",
+            "  @BeforeAll",
+            "  public void setUp2() {}",
+            "",
+            "  @Override",
+            "  @BeforeAll",
+            "  protected void setUp3() {}",
+            "",
+            "  @Override",
+            "  @BeforeEach",
+            "  void setup5() {}",
+            "",
+            "  @Override",
+            "  @BeforeEach",
+            "  public void setUp6() {}",
+            "",
+            "  @Override",
+            "  @BeforeEach",
+            "  protected void setUp7() {}",
+            "",
+            "  @Override",
+            "  @AfterEach",
+            "  void tearDown1() {}",
+            "",
+            "  @Override",
+            "  @AfterEach",
+            "  public void tearDown2() {}",
+            "",
+            "  @Override",
+            "  @AfterEach",
+            "  protected void tearDown3() {}",
+            "",
+            "  @Override",
+            "  @AfterAll",
+            "  void tearDown5() {}",
+            "",
+            "  @Override",
+            "  @AfterAll",
+            "  public void tearDown6() {}",
+            "",
+            "  @Override",
+            "  @AfterAll",
+            "  protected void tearDown7() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  void method1() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  void testMethod2() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  public void method3() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  protected void method4() {}",
+            "",
+            "  @Override",
+            "  @ParameterizedTest",
+            "  void method6() {}",
+            "",
+            "  @Override",
+            "  @ParameterizedTest",
+            "  void testMethod7() {}",
+            "",
+            "  @Override",
+            "  @ParameterizedTest",
+            "  public void method8() {}",
+            "",
+            "  @Override",
+            "  @ParameterizedTest",
+            "  protected void method9() {}",
+            "",
+            "  @Override",
+            "  @BeforeEach",
+            "  @BeforeAll",
+            "  @AfterEach",
+            "  @AfterAll",
+            "  void testNonTestMethod1() {}",
+            "",
+            "  @Override",
+            "  public void testNonTestMethod2() {}",
+            "",
+            "  @Override",
+            "  protected void testNonTestMethod3() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  void test5() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  void testOverload() {}",
+            "",
+            "  @Override",
+            "  void overload() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  void testArguments() {}",
+            "",
+            "  @Override",
+            "  @Test",
+            "  void testPublic() {}",
+            "}")
+        .addSourceLines(
+            "C.java",
+            "import org.junit.jupiter.api.AfterAll;",
+            "import org.junit.jupiter.api.BeforeAll;",
+            "import org.junit.jupiter.api.Test;",
+            "",
+            "abstract class C {",
+            "  @BeforeAll",
+            "  public void setUp() {}",
+            "",
+            "  @Test",
+            "  void testMethod1() {}",
+            "",
+            "  @AfterAll",
+            "  // BUG: Diagnostic contains:",
+            "  private void tearDown() {}",
+            "",
+            "  @Test",
+            "  // BUG: Diagnostic contains:",
+            "  final void testMethod2() {}",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "in/A.java",
+            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
+            "",
+            "import org.junit.jupiter.api.AfterAll;",
+            "import org.junit.jupiter.api.AfterEach;",
+            "import org.junit.jupiter.api.BeforeAll;",
+            "import org.junit.jupiter.api.BeforeEach;",
+            "import org.junit.jupiter.api.RepeatedTest;",
+            "import org.junit.jupiter.api.Test;",
+            "import org.junit.jupiter.params.ParameterizedTest;",
+            "",
+            "class A {",
+            "  {",
+            "    arguments();",
+            "  }",
+            "",
+            "  @BeforeAll",
+            "  public void setUp1() {}",
+            "",
+            "  @BeforeEach",
+            "  protected void setUp2() {}",
+            "",
+            "  @AfterEach",
+            "  private void setUp3() {}",
+            "",
+            "  @AfterAll",
+            "  private void setUp4() {}",
+            "",
+            "  @Test",
+            "  void testFoo() {}",
+            "",
+            "  @ParameterizedTest",
+            "  void testBar() {}",
+            "",
+            "  @Test",
+            "  public void baz() {}",
+            "",
+            "  @RepeatedTest(2)",
+            "  private void qux() {}",
+            "",
+            "  @ParameterizedTest",
+            "  protected void quux() {}",
+            "",
+            "  @Test",
+            "  public void testOverload() {}",
+            "",
+            "  void overload() {}",
+            "",
+            "  @Test",
+            "  protected void testArguments() {}",
+            "",
+            "  @Test",
+            "  private void testClass() {}",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import static org.junit.jupiter.params.provider.Arguments.arguments;",
+            "",
+            "import org.junit.jupiter.api.AfterAll;",
+            "import org.junit.jupiter.api.AfterEach;",
+            "import org.junit.jupiter.api.BeforeAll;",
+            "import org.junit.jupiter.api.BeforeEach;",
+            "import org.junit.jupiter.api.RepeatedTest;",
+            "import org.junit.jupiter.api.Test;",
+            "import org.junit.jupiter.params.ParameterizedTest;",
+            "",
+            "class A {",
+            "  {",
+            "    arguments();",
+            "  }",
+            "",
+            "  @BeforeAll",
+            "  void setUp1() {}",
+            "",
+            "  @BeforeEach",
+            "  void setUp2() {}",
+            "",
+            "  @AfterEach",
+            "  void setUp3() {}",
+            "",
+            "  @AfterAll",
+            "  void setUp4() {}",
+            "",
+            "  @Test",
+            "  void foo() {}",
+            "",
+            "  @ParameterizedTest",
+            "  void bar() {}",
+            "",
+            "  @Test",
+            "  void baz() {}",
+            "",
+            "  @RepeatedTest(2)",
+            "  void qux() {}",
+            "",
+            "  @ParameterizedTest",
+            "  void quux() {}",
+            "",
+            "  @Test",
+            "  void testOverload() {}",
+            "",
+            "  void overload() {}",
+            "",
+            "  @Test",
+            "  void testArguments() {}",
+            "",
+            "  @Test",
+            "  void testClass() {}",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -1,199 +0,0 @@
-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;
-import org.junit.jupiter.api.Test;
-
-public final class LexicographicalAnnotationAttributeListingCheckTest {
-  private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(
-          LexicographicalAnnotationAttributeListingCheck.class, getClass());
-  private final CompilationTestHelper restrictedCompilationTestHelper =
-      CompilationTestHelper.newInstance(
-              LexicographicalAnnotationAttributeListingCheck.class, getClass())
-          .setArgs(
-              ImmutableList.of(
-                  "-XepOpt:LexicographicalAnnotationAttributeListing:Includes=pkg.A.Foo,pkg.A.Bar",
-                  "-XepOpt:LexicographicalAnnotationAttributeListing:Excludes=pkg.A.Bar#value"));
-  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(
-          LexicographicalAnnotationAttributeListingCheck.class, getClass());
-
-  @Test
-  void identification() {
-    compilationTestHelper
-        .addSourceLines(
-            "A.java",
-            "import static java.math.RoundingMode.UP;",
-            "import static java.math.RoundingMode.DOWN;",
-            "",
-            "import com.fasterxml.jackson.annotation.JsonPropertyOrder;",
-            "import io.swagger.annotations.ApiImplicitParam;",
-            "import io.swagger.annotations.ApiImplicitParams;",
-            "import io.swagger.v3.oas.annotations.Parameter;",
-            "import io.swagger.v3.oas.annotations.Parameters;",
-            "import java.math.RoundingMode;",
-            "import javax.xml.bind.annotation.XmlType;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] ints() default {};",
-            "    Class<?>[] cls() default {};",
-            "    RoundingMode[] enums() default {};",
-            "    Bar[] anns() default {};",
-            "  }",
-            "",
-            "  @interface Bar {",
-            "    String[] value() default {};",
-            "  }",
-            "",
-            "  @Foo({}) A noString();",
-            "  @Foo({\"a\"}) A oneString();",
-            "  @Foo({\"a\", \"b\"}) A sortedStrings();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({\"b\", \"a\"}) A unsortedString();",
-            "  @Foo({\"ab\", \"Ac\"}) A sortedStringCaseInsensitive();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({\"ac\", \"Ab\"}) A unsortedStringCaseInsensitive();",
-            "  @Foo({\"A\", \"a\"}) A sortedStringCaseInsensitiveWithTotalOrderFallback();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({\"a\", \"A\"}) A unsortedStringCaseInsensitiveWithTotalOrderFallback();",
-            "",
-            "  @Foo(ints = {}) A noInts();",
-            "  @Foo(ints = {0}) A oneInt();",
-            "  @Foo(ints = {0, 1}) A sortedInts();",
-            "  @Foo(ints = {1, 0}) A unsortedInts();",
-            "",
-            "  @Foo(cls = {}) A noClasses();",
-            "  @Foo(cls = {int.class}) A oneClass();",
-            "  @Foo(cls = {int.class, long.class}) A sortedClasses();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(cls = {long.class, int.class}) A unsortedClasses();",
-            "",
-            "  @Foo(enums = {}) A noEnums();",
-            "  @Foo(enums = {DOWN}) A oneEnum();",
-            "  @Foo(enums = {DOWN, UP}) A sortedEnums();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(enums = {UP, DOWN}) A unsortedEnums();",
-            "",
-            "  @Foo(anns = {}) A noAnns();",
-            "  @Foo(anns = {@Bar(\"a\")}) A oneAnn();",
-            "  @Foo(anns = {@Bar(\"a\"), @Bar(\"b\")}) A sortedAnns();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) A unsortedAnns();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(anns = {@Bar(\"a\"), @Bar({\"b\", \"a\"})}) A unsortedInnderAnns();",
-            "",
-            "  @Foo({\"a=foo\", \"a.b=bar\", \"a.c=baz\"}) A hierarchicallySorted();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({\"a.b=bar\", \"a.c=baz\", \"a=foo\"}) A hierarchicallyUnsorted();",
-            "",
-            "  @JsonPropertyOrder({\"field2\", \"field1\"}) A dto();",
-            "  @ApiImplicitParams({@ApiImplicitParam(\"p2\"), @ApiImplicitParam(\"p1\")}) A firstEndpoint();",
-            "  @Parameters({@Parameter(name = \"p2\"), @Parameter(name = \"p1\")}) A secondEndpoint();",
-            "",
-            "  @XmlType(propOrder = {\"field2\", \"field1\"})",
-            "  class Dummy {}",
-            "}")
-        .doTest();
-  }
-
-  // XXX: Note that in the output below in one instance redundant `value =` assignments are
-  // introduced. Avoiding that might make the code too complex. Instead, users can have the
-  // `CanonicalAnnotationSyntaxCheck` correct the situation in a subsequent run.
-  @Test
-  void replacement() {
-    refactoringTestHelper
-        .addInputLines(
-            "in/A.java",
-            "import static java.math.RoundingMode.UP;",
-            "import static java.math.RoundingMode.DOWN;",
-            "",
-            "import java.math.RoundingMode;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    Class<?>[] cls() default {};",
-            "    RoundingMode[] enums() default {};",
-            "    Bar[] anns() default {};",
-            "  }",
-            "",
-            "  @interface Bar {",
-            "    String[] value() default {};",
-            "  }",
-            "",
-            "  @Foo({\"b\", \"a\"}) A unsortedString();",
-            "  @Foo(cls = {long.class, int.class}) A unsortedClasses();",
-            "  @Foo(enums = {UP, DOWN}) A unsortedEnums();",
-            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) A unsortedAnns();",
-            "  @Foo(anns = {@Bar(\"a\"), @Bar({\"b\", \"a\"})}) A unsortedInnderAnns();",
-            "}")
-        .addOutputLines(
-            "out/A.java",
-            "import static java.math.RoundingMode.UP;",
-            "import static java.math.RoundingMode.DOWN;",
-            "",
-            "import java.math.RoundingMode;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    Class<?>[] cls() default {};",
-            "    RoundingMode[] enums() default {};",
-            "    Bar[] anns() default {};",
-            "  }",
-            "",
-            "  @interface Bar {",
-            "    String[] value() default {};",
-            "  }",
-            "",
-            "  @Foo({\"a\", \"b\"}) A unsortedString();",
-            "  @Foo(cls = {int.class, long.class}) A unsortedClasses();",
-            "  @Foo(enums = {DOWN, UP}) A unsortedEnums();",
-            "  @Foo(anns = {@Bar(\"a\"), @Bar(\"b\")}) A unsortedAnns();",
-            "  @Foo(anns = {@Bar(\"a\"), @Bar({\"a\", \"b\"})}) A unsortedInnderAnns();",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-
-  @Test
-  void filtering() {
-    /* Some violations are not flagged because they are not in- or excluded. */
-    restrictedCompilationTestHelper
-        .addSourceLines(
-            "pkg/A.java",
-            "package pkg;",
-            "",
-            "interface A {",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    String[] value2() default {};",
-            "  }",
-            "",
-            "  @interface Bar {",
-            "    String[] value() default {};",
-            "    String[] value2() default {};",
-            "  }",
-            "",
-            "  @interface Baz {",
-            "    String[] value() default {};",
-            "    String[] value2() default {};",
-            "  }",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo({\"b\", \"a\"}) A fooValue();",
-            "  // BUG: Diagnostic contains:",
-            "  @Foo(value2 = {\"b\", \"a\"}) A fooValue2();",
-            "  @Bar({\"b\", \"a\"}) A barValue();",
-            "  // BUG: Diagnostic contains:",
-            "  @Bar(value2 = {\"b\", \"a\"}) A barValue2();",
-            "  @Baz({\"b\", \"a\"}) A bazValue();",
-            "  @Baz(value2 = {\"b\", \"a\"}) A bazValue2();",
-            "}")
-        .doTest();
-  }
-}

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

@@ -0,0 +1,294 @@
+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;
+import org.junit.jupiter.api.Test;
+
+final class LexicographicalAnnotationAttributeListingTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(
+          LexicographicalAnnotationAttributeListing.class, getClass());
+  private final CompilationTestHelper restrictedCompilationTestHelper =
+      CompilationTestHelper.newInstance(LexicographicalAnnotationAttributeListing.class, getClass())
+          .setArgs(
+              ImmutableList.of(
+                  "-XepOpt:LexicographicalAnnotationAttributeListing:Includes=pkg.A.Foo,pkg.A.Bar",
+                  "-XepOpt:LexicographicalAnnotationAttributeListing:Excludes=pkg.A.Bar#value"));
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(
+          LexicographicalAnnotationAttributeListing.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static java.math.RoundingMode.DOWN;",
+            "import static java.math.RoundingMode.UP;",
+            "",
+            "import com.fasterxml.jackson.annotation.JsonPropertyOrder;",
+            "import io.swagger.annotations.ApiImplicitParam;",
+            "import io.swagger.annotations.ApiImplicitParams;",
+            "import io.swagger.v3.oas.annotations.Parameter;",
+            "import io.swagger.v3.oas.annotations.Parameters;",
+            "import java.math.RoundingMode;",
+            "import javax.xml.bind.annotation.XmlType;",
+            "import org.springframework.context.annotation.PropertySource;",
+            "import org.springframework.test.context.TestPropertySource;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] ints() default {};",
+            "",
+            "    Class<?>[] cls() default {};",
+            "",
+            "    RoundingMode[] enums() default {};",
+            "",
+            "    Bar[] anns() default {};",
+            "  }",
+            "",
+            "  @interface Bar {",
+            "    String[] value() default {};",
+            "  }",
+            "",
+            "  @Foo({})",
+            "  A noString();",
+            "",
+            "  @Foo({\"a\"})",
+            "  A oneString();",
+            "",
+            "  @Foo({\"a\", \"b\"})",
+            "  A sortedStrings();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({\"b\", \"a\"})",
+            "  A unsortedString();",
+            "",
+            "  @Foo({\"ab\", \"Ac\"})",
+            "  A sortedStringCaseInsensitive();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({\"ac\", \"Ab\"})",
+            "  A unsortedStringCaseInsensitive();",
+            "",
+            "  @Foo({\"A\", \"a\"})",
+            "  A sortedStringCaseInsensitiveWithTotalOrderFallback();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({\"a\", \"A\"})",
+            "  A unsortedStringCaseInsensitiveWithTotalOrderFallback();",
+            "",
+            "  @Foo(ints = {})",
+            "  A noInts();",
+            "",
+            "  @Foo(ints = {0})",
+            "  A oneInt();",
+            "",
+            "  @Foo(ints = {0, 1})",
+            "  A sortedInts();",
+            "",
+            "  @Foo(ints = {1, 0})",
+            "  A unsortedInts();",
+            "",
+            "  @Foo(cls = {})",
+            "  A noClasses();",
+            "",
+            "  @Foo(cls = {int.class})",
+            "  A oneClass();",
+            "",
+            "  @Foo(cls = {int.class, long.class})",
+            "  A sortedClasses();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(cls = {long.class, int.class})",
+            "  A unsortedClasses();",
+            "",
+            "  @Foo(enums = {})",
+            "  A noEnums();",
+            "",
+            "  @Foo(enums = {DOWN})",
+            "  A oneEnum();",
+            "",
+            "  @Foo(enums = {DOWN, UP})",
+            "  A sortedEnums();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(enums = {UP, DOWN})",
+            "  A unsortedEnums();",
+            "",
+            "  @Foo(anns = {})",
+            "  A noAnns();",
+            "",
+            "  @Foo(anns = {@Bar(\"a\")})",
+            "  A oneAnn();",
+            "",
+            "  @Foo(anns = {@Bar(\"a\"), @Bar(\"b\")})",
+            "  A sortedAnns();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  A unsortedAnns();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(anns = {@Bar(\"a\"), @Bar({\"b\", \"a\"})})",
+            "  A unsortedInnderAnns();",
+            "",
+            "  @Foo({\"a=foo\", \"a.b=bar\", \"a.c=baz\"})",
+            "  A hierarchicallySorted();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({\"a.b=bar\", \"a.c=baz\", \"a=foo\"})",
+            "  A hierarchicallyUnsorted();",
+            "",
+            "  @JsonPropertyOrder({\"field2\", \"field1\"})",
+            "  A dto();",
+            "",
+            "  @ApiImplicitParams({@ApiImplicitParam(\"p2\"), @ApiImplicitParam(\"p1\")})",
+            "  A firstEndpoint();",
+            "",
+            "  @Parameters({@Parameter(name = \"p2\"), @Parameter(name = \"p1\")})",
+            "  A secondEndpoint();",
+            "",
+            "  @XmlType(propOrder = {\"field2\", \"field1\"})",
+            "  class XmlTypeDummy {}",
+            "",
+            "  @PropertySource({\"field2\", \"field1\"})",
+            "  class PropertySourceDummy {}",
+            "",
+            "  @TestPropertySource(locations = {\"field2\", \"field1\"})",
+            "  class FirstTestPropertySourceDummy {}",
+            "",
+            "  @TestPropertySource({\"field2\", \"field1\"})",
+            "  class SecondTestPropertySourceDummy {}",
+            "}")
+        .doTest();
+  }
+
+  // XXX: Note that in the output below in one instance redundant `value =` assignments are
+  // introduced. Avoiding that might make the code too complex. Instead, users can have the
+  // `CanonicalAnnotationSyntax` checker correct the situation in a subsequent run.
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "in/A.java",
+            "import static java.math.RoundingMode.DOWN;",
+            "import static java.math.RoundingMode.UP;",
+            "",
+            "import java.math.RoundingMode;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    Class<?>[] cls() default {};",
+            "",
+            "    RoundingMode[] enums() default {};",
+            "",
+            "    Bar[] anns() default {};",
+            "  }",
+            "",
+            "  @interface Bar {",
+            "    String[] value() default {};",
+            "  }",
+            "",
+            "  @Foo({\"b\", \"a\"})",
+            "  A unsortedString();",
+            "",
+            "  @Foo(cls = {long.class, int.class})",
+            "  A unsortedClasses();",
+            "",
+            "  @Foo(enums = {UP, DOWN})",
+            "  A unsortedEnums();",
+            "",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  A unsortedAnns();",
+            "",
+            "  @Foo(anns = {@Bar(\"a\"), @Bar({\"b\", \"a\"})})",
+            "  A unsortedInnderAnns();",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import static java.math.RoundingMode.DOWN;",
+            "import static java.math.RoundingMode.UP;",
+            "",
+            "import java.math.RoundingMode;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    Class<?>[] cls() default {};",
+            "",
+            "    RoundingMode[] enums() default {};",
+            "",
+            "    Bar[] anns() default {};",
+            "  }",
+            "",
+            "  @interface Bar {",
+            "    String[] value() default {};",
+            "  }",
+            "",
+            "  @Foo({\"a\", \"b\"})",
+            "  A unsortedString();",
+            "",
+            "  @Foo(cls = {int.class, long.class})",
+            "  A unsortedClasses();",
+            "",
+            "  @Foo(enums = {DOWN, UP})",
+            "  A unsortedEnums();",
+            "",
+            "  @Foo(anns = {@Bar(\"a\"), @Bar(\"b\")})",
+            "  A unsortedAnns();",
+            "",
+            "  @Foo(anns = {@Bar(\"a\"), @Bar({\"a\", \"b\"})})",
+            "  A unsortedInnderAnns();",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+
+  @Test
+  void filtering() {
+    /* Some violations are not flagged because they are not in- or excluded. */
+    restrictedCompilationTestHelper
+        .addSourceLines(
+            "pkg/A.java",
+            "package pkg;",
+            "",
+            "interface A {",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    String[] value2() default {};",
+            "  }",
+            "",
+            "  @interface Bar {",
+            "    String[] value() default {};",
+            "",
+            "    String[] value2() default {};",
+            "  }",
+            "",
+            "  @interface Baz {",
+            "    String[] value() default {};",
+            "",
+            "    String[] value2() default {};",
+            "  }",
+            "",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo({\"b\", \"a\"})",
+            "  A fooValue();",
+            "  // BUG: Diagnostic contains:",
+            "  @Foo(value2 = {\"b\", \"a\"})",
+            "  A fooValue2();",
+            "",
+            "  @Bar({\"b\", \"a\"})",
+            "  A barValue();",
+            "  // BUG: Diagnostic contains:",
+            "  @Bar(value2 = {\"b\", \"a\"})",
+            "  A barValue2();",
+            "",
+            "  @Baz({\"b\", \"a\"})",
+            "  A bazValue();",
+            "",
+            "  @Baz(value2 = {\"b\", \"a\"})",
+            "  A bazValue2();",
+            "}")
+        .doTest();
+  }
+}

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

@@ -1,148 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.common.base.Predicates.containsPattern;
-
-import com.google.errorprone.BugCheckerRefactoringTestHelper;
-import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
-import com.google.errorprone.CompilationTestHelper;
-import org.junit.jupiter.api.Test;
-
-public final class LexicographicalAnnotationListingCheckTest {
-  private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(LexicographicalAnnotationListingCheck.class, getClass())
-          .expectErrorMessage(
-              "X", containsPattern("Sort annotations lexicographically where possible"));
-  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(
-          LexicographicalAnnotationListingCheck.class, getClass());
-
-  @Test
-  void identification() {
-    compilationTestHelper
-        .addSourceLines(
-            "A.java",
-            "import java.lang.annotation.Repeatable;",
-            "",
-            "interface A {",
-            "  @Repeatable(Foos.class)",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] ints() default {};",
-            "    Bar[] anns() default {};",
-            "  }",
-            "",
-            "  @interface Bar {",
-            "    String[] value() default {};",
-            "  }",
-            "",
-            "  @interface Baz {",
-            "    String[] str() default {};",
-            "  }",
-            "",
-            "  @interface Foos {",
-            "     Foo[] value();",
-            "  }",
-            "",
-            "  // BUG: Diagnostic matches: X",
-            "  @Foo @Bar A unsortedSimpleCase();",
-            "  // BUG: Diagnostic matches: X",
-            "  @Foo() @Bar() A unsortedWithParens();",
-            "  @Foo() A onlyOneAnnotation();",
-            "  @Bar @Foo() A sortedAnnotationsOneWithParens();",
-            "",
-            "  // BUG: Diagnostic matches: X",
-            "  @Foo @Baz @Bar A threeUnsortedAnnotationsSameInitialLetter();",
-            "  // BUG: Diagnostic matches: X",
-            "  @Bar @Foo() @Baz A firstOrderedWithTwoUnsortedAnnotations();",
-            "  @Bar @Baz @Foo() A threeSortedAnnotations();",
-            "",
-            "  // BUG: Diagnostic matches: X",
-            "  @Foo({\"b\"}) @Bar({\"a\"}) A unsortedWithStringAttributes();",
-            "  // BUG: Diagnostic matches: X",
-            "  @Baz(str = {\"a\", \"b\"}) @Foo(ints = {1, 0}) @Bar A unsortedWithAttributes();",
-            "  // BUG: Diagnostic matches: X",
-            "  @Bar @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Baz A unsortedWithNestedBar();",
-            "  @Bar @Baz @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})  A sortedWithNestedBar();",
-            "",
-            " @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Foo(ints = {1, 2}) @Foo({\"b\"}) A sortedRepeatableAnnotation();",
-            "  // BUG: Diagnostic matches: X",
-            " @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Bar @Foo(ints = {1, 2}) A unsortedRepeatableAnnotation();",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void replacement() {
-    refactoringTestHelper
-        .addInputLines(
-            "in/A.java",
-            "import java.lang.annotation.Repeatable;",
-            "interface A {",
-            "  @Repeatable(Foos.class)",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] ints() default {};",
-            "    Bar[] anns() default {};",
-            "  }",
-            "",
-            "  @interface Bar {",
-            "    String[] value() default {};",
-            "  }",
-            "",
-            "  @interface Baz {",
-            "    String[] str() default {};",
-            "  }",
-            "",
-            "  @interface Foos {",
-            "     Foo[] value();",
-            "  }",
-            "",
-            "  @Bar A singleAnnotation();",
-            "  @Bar @Foo A sortedAnnotations();",
-            "  @Foo @Bar A unsortedAnnotations();",
-            "  @Foo() @Baz() @Bar A unsortedAnnotationsWithSomeParens();",
-            "",
-            "  @Bar @Baz(str = {\"a\", \"b\"}) @Foo() A unsortedAnnotationsOneContainingAttributes();",
-            "  @Baz(str = {\"a\", \"b\"}) @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Bar({\"b\"}) A unsortedAnnotationsWithAttributes();",
-            "",
-            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Foo(ints = {1, 2}) @Foo({\"b\"}) A sortedRepeatableAnnotation();",
-            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Bar @Foo(ints = {1, 2}) A unsortedRepeatableAnnotation();",
-            "",
-            "}")
-        .addOutputLines(
-            "out/A.java",
-            "import java.lang.annotation.Repeatable;",
-            "interface A {",
-            "  @Repeatable(Foos.class)",
-            "  @interface Foo {",
-            "    String[] value() default {};",
-            "    int[] ints() default {};",
-            "    Bar[] anns() default {};",
-            "  }",
-            "",
-            "  @interface Bar {",
-            "    String[] value() default {};",
-            "  }",
-            "",
-            "  @interface Baz {",
-            "    String[] str() default {};",
-            "  }",
-            "",
-            "  @interface Foos {",
-            "     Foo[] value();",
-            "  }",
-            "  @Bar A singleAnnotation();",
-            "  @Bar @Foo A sortedAnnotations();",
-            "  @Bar @Foo A unsortedAnnotations();",
-            "  @Bar @Baz() @Foo() A unsortedAnnotationsWithSomeParens();",
-            "",
-            "  @Bar @Baz(str = {\"a\", \"b\"}) @Foo() A unsortedAnnotationsOneContainingAttributes();",
-            "  @Bar({\"b\"}) @Baz(str = {\"a\", \"b\"}) @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) A unsortedAnnotationsWithAttributes();",
-            "",
-            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Foo(ints = {1, 2}) @Foo({\"b\"}) A sortedRepeatableAnnotation();",
-            "  @Bar @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")}) @Foo(ints = {1, 2}) A unsortedRepeatableAnnotation();",
-            "",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-}

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

@@ -0,0 +1,242 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.common.base.Predicates.containsPattern;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class LexicographicalAnnotationListingTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(LexicographicalAnnotationListing.class, getClass())
+          .expectErrorMessage(
+              "X", containsPattern("Sort annotations lexicographically where possible"));
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(
+          LexicographicalAnnotationListing.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import java.lang.annotation.Repeatable;",
+            "",
+            "interface A {",
+            "  @Repeatable(Foos.class)",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] ints() default {};",
+            "",
+            "    Bar[] anns() default {};",
+            "  }",
+            "",
+            "  @interface Bar {",
+            "    String[] value() default {};",
+            "  }",
+            "",
+            "  @interface Baz {",
+            "    String[] str() default {};",
+            "  }",
+            "",
+            "  @interface Foos {",
+            "    Foo[] value();",
+            "  }",
+            "",
+            "  // BUG: Diagnostic matches: X",
+            "  @Foo",
+            "  @Bar",
+            "  A unsortedSimpleCase();",
+            "  // BUG: Diagnostic matches: X",
+            "  @Foo()",
+            "  @Bar()",
+            "  A unsortedWithParens();",
+            "",
+            "  @Foo()",
+            "  A onlyOneAnnotation();",
+            "",
+            "  @Bar",
+            "  @Foo()",
+            "  A sortedAnnotationsOneWithParens();",
+            "",
+            "  // BUG: Diagnostic matches: X",
+            "  @Foo",
+            "  @Baz",
+            "  @Bar",
+            "  A threeUnsortedAnnotationsSameInitialLetter();",
+            "  // BUG: Diagnostic matches: X",
+            "  @Bar",
+            "  @Foo()",
+            "  @Baz",
+            "  A firstOrderedWithTwoUnsortedAnnotations();",
+            "",
+            "  @Bar",
+            "  @Baz",
+            "  @Foo()",
+            "  A threeSortedAnnotations();",
+            "",
+            "  // BUG: Diagnostic matches: X",
+            "  @Foo({\"b\"})",
+            "  @Bar({\"a\"})",
+            "  A unsortedWithStringAttributes();",
+            "  // BUG: Diagnostic matches: X",
+            "  @Baz(str = {\"a\", \"b\"})",
+            "  @Foo(ints = {1, 0})",
+            "  @Bar",
+            "  A unsortedWithAttributes();",
+            "  // BUG: Diagnostic matches: X",
+            "  @Bar",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Baz",
+            "  A unsortedWithNestedBar();",
+            "",
+            "  @Bar",
+            "  @Baz",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  A sortedWithNestedBar();",
+            "",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Foo(ints = {1, 2})",
+            "  @Foo({\"b\"})",
+            "  A sortedRepeatableAnnotation();",
+            "  // BUG: Diagnostic matches: X",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Bar",
+            "  @Foo(ints = {1, 2})",
+            "  A unsortedRepeatableAnnotation();",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "in/A.java",
+            "import java.lang.annotation.Repeatable;",
+            "",
+            "interface A {",
+            "  @Repeatable(Foos.class)",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] ints() default {};",
+            "",
+            "    Bar[] anns() default {};",
+            "  }",
+            "",
+            "  @interface Bar {",
+            "    String[] value() default {};",
+            "  }",
+            "",
+            "  @interface Baz {",
+            "    String[] str() default {};",
+            "  }",
+            "",
+            "  @interface Foos {",
+            "    Foo[] value();",
+            "  }",
+            "",
+            "  @Bar",
+            "  A singleAnnotation();",
+            "",
+            "  @Bar",
+            "  @Foo",
+            "  A sortedAnnotations();",
+            "",
+            "  @Foo",
+            "  @Bar",
+            "  A unsortedAnnotations();",
+            "",
+            "  @Foo()",
+            "  @Baz()",
+            "  @Bar",
+            "  A unsortedAnnotationsWithSomeParens();",
+            "",
+            "  @Bar",
+            "  @Baz(str = {\"a\", \"b\"})",
+            "  @Foo()",
+            "  A unsortedAnnotationsOneContainingAttributes();",
+            "",
+            "  @Baz(str = {\"a\", \"b\"})",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Bar({\"b\"})",
+            "  A unsortedAnnotationsWithAttributes();",
+            "",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Foo(ints = {1, 2})",
+            "  @Foo({\"b\"})",
+            "  A sortedRepeatableAnnotation();",
+            "",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Bar",
+            "  @Foo(ints = {1, 2})",
+            "  A unsortedRepeatableAnnotation();",
+            "}")
+        .addOutputLines(
+            "out/A.java",
+            "import java.lang.annotation.Repeatable;",
+            "",
+            "interface A {",
+            "  @Repeatable(Foos.class)",
+            "  @interface Foo {",
+            "    String[] value() default {};",
+            "",
+            "    int[] ints() default {};",
+            "",
+            "    Bar[] anns() default {};",
+            "  }",
+            "",
+            "  @interface Bar {",
+            "    String[] value() default {};",
+            "  }",
+            "",
+            "  @interface Baz {",
+            "    String[] str() default {};",
+            "  }",
+            "",
+            "  @interface Foos {",
+            "    Foo[] value();",
+            "  }",
+            "",
+            "  @Bar",
+            "  A singleAnnotation();",
+            "",
+            "  @Bar",
+            "  @Foo",
+            "  A sortedAnnotations();",
+            "",
+            "  @Bar",
+            "  @Foo",
+            "  A unsortedAnnotations();",
+            "",
+            "  @Bar",
+            "  @Baz()",
+            "  @Foo()",
+            "  A unsortedAnnotationsWithSomeParens();",
+            "",
+            "  @Bar",
+            "  @Baz(str = {\"a\", \"b\"})",
+            "  @Foo()",
+            "  A unsortedAnnotationsOneContainingAttributes();",
+            "",
+            "  @Bar({\"b\"})",
+            "  @Baz(str = {\"a\", \"b\"})",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  A unsortedAnnotationsWithAttributes();",
+            "",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Foo(ints = {1, 2})",
+            "  @Foo({\"b\"})",
+            "  A sortedRepeatableAnnotation();",
+            "",
+            "  @Bar",
+            "  @Foo(anns = {@Bar(\"b\"), @Bar(\"a\")})",
+            "  @Foo(ints = {1, 2})",
+            "  A unsortedRepeatableAnnotation();",
+            "}")
+        .doTest(TestMode.TEXT_MATCH);
+  }
+}

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

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class MethodReferenceUsageCheckTest {
+final class MethodReferenceUsageTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(MethodReferenceUsageCheck.class, getClass());
+      CompilationTestHelper.newInstance(MethodReferenceUsage.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(MethodReferenceUsageCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(MethodReferenceUsage.class, getClass());
 
   @Test
   void identification() {
@@ -17,37 +17,62 @@ public final class MethodReferenceUsageCheckTest {
         .addSourceLines(
             "A.java",
             "import com.google.common.collect.Streams;",
-            "import java.util.Map;",
             "import java.util.HashMap;",
-            "import java.util.stream.Stream;",
+            "import java.util.Map;",
             "import java.util.function.IntConsumer;",
             "import java.util.function.IntFunction;",
+            "import java.util.stream.Stream;",
             "",
             "class A {",
             "  private final Stream<Integer> s = Stream.of(1);",
             "  private final Map<Integer, Integer> m = new HashMap<>();",
-            "  private final Runnable thrower = () -> { throw new RuntimeException(); };",
+            "  private final Runnable thrower =",
+            "      () -> {",
+            "        throw new RuntimeException();",
+            "      };",
             "",
             "  void unaryExternalStaticFunctionCalls() {",
             "    s.forEach(String::valueOf);",
             "    // BUG: Diagnostic contains:",
             "    s.forEach(v -> String.valueOf(v));",
-            "    // BUG: Diagnostic contains:",
-            "    s.forEach((v) -> { String.valueOf(v); });",
-            "    // BUG: Diagnostic contains:",
-            "    s.forEach((Integer v) -> { { String.valueOf(v); } });",
-            "    s.forEach(v -> { String.valueOf(v); String.valueOf(v); });",
+            "    s.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (v) -> {",
+            "          String.valueOf(v);",
+            "        });",
+            "    s.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (Integer v) -> {",
+            "          {",
+            "            String.valueOf(v);",
+            "          }",
+            "        });",
+            "    s.forEach(",
+            "        v -> {",
+            "          String.valueOf(v);",
+            "          String.valueOf(v);",
+            "        });",
             "",
             "    s.map(String::valueOf);",
             "    // BUG: Diagnostic contains:",
             "    s.map(v -> String.valueOf(v));",
             "    // BUG: Diagnostic contains:",
             "    s.map((v) -> (String.valueOf(v)));",
-            "    // BUG: Diagnostic contains:",
-            "    s.map((Integer v) -> { return String.valueOf(v); });",
-            "    // BUG: Diagnostic contains:",
-            "    s.map((final Integer v) -> { return (String.valueOf(v)); });",
-            "    s.map(v -> { String.valueOf(v); return String.valueOf(v); });",
+            "    s.map(",
+            "        // BUG: Diagnostic contains:",
+            "        (Integer v) -> {",
+            "          return String.valueOf(v);",
+            "        });",
+            "    s.map(",
+            "        // BUG: Diagnostic contains:",
+            "        (final Integer v) -> {",
+            "          return (String.valueOf(v));",
+            "        });",
+            "    s.map(",
+            "        v -> {",
+            "          String.valueOf(v);",
+            "          return String.valueOf(v);",
+            "        });",
             "",
             "    s.findFirst().orElseGet(() -> Integer.valueOf(\"0\"));",
             "    m.forEach((k, v) -> String.valueOf(v));",
@@ -59,14 +84,34 @@ public final class MethodReferenceUsageCheckTest {
             "    // BUG: Diagnostic contains:",
             "    m.forEach((k, v) -> m.put(k, v));",
             "    m.forEach((k, v) -> m.put(v, k));",
-            "    // BUG: Diagnostic contains:",
-            "    m.forEach((Integer k, Integer v) -> { m.put(k, v); });",
-            "    m.forEach((k, v) -> { m.put(k, k); });",
-            "    // BUG: Diagnostic contains:",
-            "    m.forEach((final Integer k, final Integer v) -> { { m.put(k, v); } });",
-            "    m.forEach((k, v) -> { { m.put(v, v); } });",
+            "    m.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (Integer k, Integer v) -> {",
+            "          m.put(k, v);",
+            "        });",
+            "    m.forEach(",
+            "        (k, v) -> {",
+            "          m.put(k, k);",
+            "        });",
+            "    m.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (final Integer k, final Integer v) -> {",
+            "          {",
+            "            m.put(k, v);",
+            "          }",
+            "        });",
+            "    m.forEach(",
+            "        (k, v) -> {",
+            "          {",
+            "            m.put(v, v);",
+            "          }",
+            "        });",
             "    m.forEach((k, v) -> new HashMap<Integer, Integer>().put(k, v));",
-            "    m.forEach((k, v) -> { m.put(k, v); m.put(k, v); });",
+            "    m.forEach(",
+            "        (k, v) -> {",
+            "          m.put(k, v);",
+            "          m.put(k, v);",
+            "        });",
             "",
             "    Streams.zip(s, s, m::put);",
             "    // BUG: Diagnostic contains:",
@@ -75,20 +120,45 @@ public final class MethodReferenceUsageCheckTest {
             "    // BUG: Diagnostic contains:",
             "    Streams.zip(s, s, (Integer a, Integer b) -> (m.put(a, b)));",
             "    Streams.zip(s, s, (a, b) -> (m.put(a, a)));",
-            "    // BUG: Diagnostic contains:",
-            "    Streams.zip(s, s, (final Integer a, final Integer b) -> { return m.put(a, b); });",
-            "    Streams.zip(s, s, (a, b) -> { return m.put(b, b); });",
-            "    // BUG: Diagnostic contains:",
-            "    Streams.zip(s, s, (a, b) -> { return (m.put(a, b)); });",
-            "    Streams.zip(s, s, (a, b) -> { return (m.put(b, a)); });",
-            "    Streams.zip(s, s, (a, b) -> { m.put(a, b); return m.put(a, b); });",
+            "    Streams.zip(",
+            "        s,",
+            "        s,",
+            "        // BUG: Diagnostic contains:",
+            "        (final Integer a, final Integer b) -> {",
+            "          return m.put(a, b);",
+            "        });",
+            "    Streams.zip(",
+            "        s,",
+            "        s,",
+            "        (a, b) -> {",
+            "          return m.put(b, b);",
+            "        });",
+            "    Streams.zip(",
+            "        s,",
+            "        s,",
+            "        // BUG: Diagnostic contains:",
+            "        (a, b) -> {",
+            "          return (m.put(a, b));",
+            "        });",
+            "    Streams.zip(",
+            "        s,",
+            "        s,",
+            "        (a, b) -> {",
+            "          return (m.put(b, a));",
+            "        });",
+            "    Streams.zip(",
+            "        s,",
+            "        s,",
+            "        (a, b) -> {",
+            "          m.put(a, b);",
+            "          return m.put(a, b);",
+            "        });",
             "  }",
             "",
             "  void nullaryExternalInstanceFunctionCalls() {",
             "    s.map(Integer::doubleValue);",
             "    // BUG: Diagnostic contains:",
             "    s.map(i -> i.doubleValue());",
-            // `s.map(Integer::toString)` is ambiguous
             "    s.map(i -> i.toString());",
             "    s.map(i -> s.toString());",
             "",
@@ -108,24 +178,36 @@ public final class MethodReferenceUsageCheckTest {
             "    s.forEach(this::ivoid1);",
             "    // BUG: Diagnostic contains:",
             "    s.forEach(v -> ivoid1(v));",
-            "    // BUG: Diagnostic contains:",
-            "    s.forEach(v -> { ivoid1(v); });",
+            "    s.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        v -> {",
+            "          ivoid1(v);",
+            "        });",
             "    s.forEach(this::iint1);",
             "    // BUG: Diagnostic contains:",
             "    s.forEach(v -> iint1(v));",
-            "    // BUG: Diagnostic contains:",
-            "    s.forEach(v -> { iint1(v); });",
+            "    s.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        v -> {",
+            "          iint1(v);",
+            "        });",
             "",
             "    s.forEach(A::svoid1);",
             "    // BUG: Diagnostic contains:",
             "    s.forEach(v -> svoid1(v));",
-            "    // BUG: Diagnostic contains:",
-            "    s.forEach(v -> { svoid1(v); });",
+            "    s.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        v -> {",
+            "          svoid1(v);",
+            "        });",
             "    s.forEach(A::sint1);",
             "    // BUG: Diagnostic contains:",
             "    s.forEach(v -> sint1(v));",
-            "    // BUG: Diagnostic contains:",
-            "    s.forEach(v -> { sint1(v); });",
+            "    s.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        v -> {",
+            "          sint1(v);",
+            "        });",
             "",
             "    s.forEach(v -> ivoid2(v, v));",
             "    s.forEach(v -> iint2(v, v));",
@@ -140,28 +222,43 @@ public final class MethodReferenceUsageCheckTest {
             "    m.forEach(this::ivoid2);",
             "    // BUG: Diagnostic contains:",
             "    m.forEach((k, v) -> ivoid2(k, v));",
-            "    // BUG: Diagnostic contains:",
-            "    m.forEach((k, v) -> { ivoid2(k, v); });",
+            "    m.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (k, v) -> {",
+            "          ivoid2(k, v);",
+            "        });",
             "    m.forEach(this::iint2);",
             "    // BUG: Diagnostic contains:",
             "    m.forEach((k, v) -> iint2(k, v));",
-            "    // BUG: Diagnostic contains:",
-            "    m.forEach((k, v) -> { iint2(k, v); });",
+            "    m.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (k, v) -> {",
+            "          iint2(k, v);",
+            "        });",
             "",
             "    m.forEach(A::svoid2);",
             "    // BUG: Diagnostic contains:",
             "    m.forEach((k, v) -> svoid2(k, v));",
-            "    // BUG: Diagnostic contains:",
-            "    m.forEach((k, v) -> { svoid2(k, v); });",
+            "    m.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (k, v) -> {",
+            "          svoid2(k, v);",
+            "        });",
             "    m.forEach(A::sint2);",
             "    // BUG: Diagnostic contains:",
             "    m.forEach((k, v) -> sint2(k, v));",
-            "    // BUG: Diagnostic contains:",
-            "    m.forEach((k, v) -> { sint2(k, v); });",
+            "    m.forEach(",
+            "        // BUG: Diagnostic contains:",
+            "        (k, v) -> {",
+            "          sint2(k, v);",
+            "        });",
             "  }",
             "",
             "  void functionCallsWhoseReplacementWouldBeAmbiguous() {",
-            "    receiver(i -> { Integer.toString(i); });",
+            "    receiver(",
+            "        i -> {",
+            "          Integer.toString(i);",
+            "        });",
             "  }",
             "",
             "  void assortedOtherEdgeCases() {",
@@ -175,23 +272,47 @@ public final class MethodReferenceUsageCheckTest {
             "    TernaryOp o7 = (a, b, c) -> b.concat(c);",
             "  }",
             "",
-            "  void receiver(IntFunction<?> op) { }",
-            "  void receiver(IntConsumer op) { }",
+            "  void receiver(IntFunction<?> op) {}",
             "",
-            "  void ivoid0() { }",
-            "  void ivoid1(int a) { }",
-            "  void ivoid2(int a, int b) { }",
-            "  int iint0() { return 0; }",
-            "  int iint1(int a) { return 0; }",
-            "  int iint2(int a, int b) { return 0; }",
+            "  void receiver(IntConsumer op) {}",
             "",
-            "  static void svoid0() { }",
-            "  static void svoid1(int a) { }",
-            "  static void svoid2(int a, int b) { }",
-            "  static void svoid3(int a, int b, int c) { }",
-            "  static int sint0() { return 0; }",
-            "  static int sint1(int a) { return 0; }",
-            "  static int sint2(int a, int b) { return 0; }",
+            "  void ivoid0() {}",
+            "",
+            "  void ivoid1(int a) {}",
+            "",
+            "  void ivoid2(int a, int b) {}",
+            "",
+            "  int iint0() {",
+            "    return 0;",
+            "  }",
+            "",
+            "  int iint1(int a) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  int iint2(int a, int b) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  static void svoid0() {}",
+            "",
+            "  static void svoid1(int a) {}",
+            "",
+            "  static void svoid2(int a, int b) {}",
+            "",
+            "  static void svoid3(int a, int b, int c) {}",
+            "",
+            "  static int sint0() {",
+            "    return 0;",
+            "  }",
+            "",
+            "  static int sint1(int a) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  static int sint2(int a, int b) {",
+            "    return 0;",
+            "  }",
             "",
             "  interface TernaryOp {",
             "    String collect(String a, String b, String c);",
@@ -210,9 +331,6 @@ public final class MethodReferenceUsageCheckTest {
             "import java.util.Collections;",
             "import java.util.List;",
             "import java.util.Map;",
-            // Don't import `java.util.Set`; it should be added.
-            "import java.util.function.IntConsumer;",
-            "import java.util.function.IntFunction;",
             "import java.util.function.IntSupplier;",
             "import java.util.function.Supplier;",
             "import java.util.stream.Stream;",
@@ -245,12 +363,19 @@ public final class MethodReferenceUsageCheckTest {
             "      Stream.of((Map<?, ?>) null).map(Map::keySet).map(s -> s.size());",
             "    }",
             "",
-            "    @Override int iint0() { return 0; }",
+            "    @Override",
+            "    int iint0() {",
+            "      return 0;",
+            "    }",
             "  }",
             "",
-            "  int iint0() { return 0; }",
+            "  int iint0() {",
+            "    return 0;",
+            "  }",
             "",
-            "  static int sint0() { return 0; }",
+            "  static int sint0() {",
+            "    return 0;",
+            "  }",
             "}")
         .addOutputLines(
             "out/A.java",
@@ -260,8 +385,6 @@ public final class MethodReferenceUsageCheckTest {
             "import java.util.List;",
             "import java.util.Map;",
             "import java.util.Set;",
-            "import java.util.function.IntConsumer;",
-            "import java.util.function.IntFunction;",
             "import java.util.function.IntSupplier;",
             "import java.util.function.Supplier;",
             "import java.util.stream.Stream;",
@@ -294,12 +417,19 @@ public final class MethodReferenceUsageCheckTest {
             "      Stream.of((Map<?, ?>) null).map(Map::keySet).map(Set::size);",
             "    }",
             "",
-            "    @Override int iint0() { return 0; }",
+            "    @Override",
+            "    int iint0() {",
+            "      return 0;",
+            "    }",
             "  }",
             "",
-            "  int iint0() { return 0; }",
+            "  int iint0() {",
+            "    return 0;",
+            "  }",
             "",
-            "  static int sint0() { return 0; }",
+            "  static int sint0() {",
+            "    return 0;",
+            "  }",
             "}")
         .doTest(TestMode.TEXT_MATCH);
   }

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

@@ -5,9 +5,9 @@ import static com.google.common.base.Predicates.containsPattern;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class MissingRefasterAnnotationCheckTest {
+final class MissingRefasterAnnotationTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(MissingRefasterAnnotationCheck.class, getClass())
+      CompilationTestHelper.newInstance(MissingRefasterAnnotation.class, getClass())
           .expectErrorMessage(
               "X",
               containsPattern(

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

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class MockitoStubbingCheckTest {
+final class MockitoStubbingTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(MockitoStubbingCheck.class, getClass());
+      CompilationTestHelper.newInstance(MockitoStubbing.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(MockitoStubbingCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(MockitoStubbing.class, getClass());
 
   @Test
   void identification() {
@@ -42,8 +42,10 @@ public final class MockitoStubbingCheckTest {
             "    doAnswer(inv -> null).when(biConsumer).accept(0, \"foo\");",
             "    doAnswer(inv -> null).when(biConsumer).accept(eq(0), notNull());",
             "    doAnswer(inv -> null).when(biConsumer).accept(notNull(), eq(\"foo\"));",
-            "    // BUG: Diagnostic contains:",
-            "    doAnswer(inv -> null).when(biConsumer).accept(ArgumentMatchers.eq(0), ArgumentMatchers.eq(\"foo\"));",
+            "    doAnswer(inv -> null)",
+            "        .when(biConsumer)",
+            "        // BUG: Diagnostic contains:",
+            "        .accept(ArgumentMatchers.eq(0), ArgumentMatchers.eq(\"foo\"));",
             "    // BUG: Diagnostic contains:",
             "    doAnswer(inv -> null).when(biConsumer).accept(eq(hashCode()), eq(toString()));",
             "  }",
@@ -71,7 +73,9 @@ public final class MockitoStubbingCheckTest {
             "    doAnswer(inv -> null).when(consumer).accept(eq(toString()));",
             "",
             "    BiConsumer<Integer, String> biConsumer = mock(BiConsumer.class);",
-            "    doAnswer(inv -> null).when(biConsumer).accept(ArgumentMatchers.eq(0), ArgumentMatchers.eq(\"foo\"));",
+            "    doAnswer(inv -> null)",
+            "        .when(biConsumer)",
+            "        .accept(ArgumentMatchers.eq(0), ArgumentMatchers.eq(\"foo\"));",
             "    doAnswer(inv -> null).when(biConsumer).accept(eq(hashCode()), eq(toString()));",
             "  }",
             "}")

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

@@ -0,0 +1,42 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class NestedOptionalsTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(NestedOptionals.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import java.util.Optional;",
+            "import java.util.stream.Stream;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Optional.empty();",
+            "    Optional.of(1);",
+            "    // BUG: Diagnostic contains:",
+            "    Optional.of(Optional.empty());",
+            "    // BUG: Diagnostic contains:",
+            "    Optional.of(Optional.of(1));",
+            "",
+            "    Optional.ofNullable(null);",
+            "    // BUG: Diagnostic contains:",
+            "    Optional.ofNullable((Optional) null);",
+            "",
+            "    Optional.of(\"foo\").map(String::length);",
+            "    // BUG: Diagnostic contains:",
+            "    Optional.of(\"foo\").map(Optional::of);",
+            "",
+            "    Stream.of(\"foo\").findFirst();",
+            "    // BUG: Diagnostic contains:",
+            "    Stream.of(\"foo\").map(Optional::of).findFirst();",
+            "  }",
+            "}")
+        .doTest();
+  }
+}

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

@@ -0,0 +1,155 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import static com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode.TEXT_MATCH;
+
+import com.google.errorprone.BugCheckerRefactoringTestHelper;
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class NonEmptyMonoTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(NonEmptyMono.class, getClass());
+  private final BugCheckerRefactoringTestHelper refactoringTestHelper =
+      BugCheckerRefactoringTestHelper.newInstance(NonEmptyMono.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "import static java.util.function.Function.identity;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import com.google.common.collect.ImmutableMap;",
+            "import java.util.ArrayList;",
+            "import java.util.HashMap;",
+            "import java.util.List;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.core.publisher.Mono;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Mono.just(1).defaultIfEmpty(2);",
+            "    Mono.just(1).single();",
+            "    Mono.just(1).switchIfEmpty(Mono.just(2));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).all(x -> true).defaultIfEmpty(true);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).any(x -> true).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collect(toImmutableList()).switchIfEmpty(Mono.just(ImmutableList.of()));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collect(ArrayList::new, List::add).defaultIfEmpty(new ArrayList<>());",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectList().single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMap(identity()).switchIfEmpty(Mono.just(ImmutableMap.of()));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMap(identity(), identity()).defaultIfEmpty(ImmutableMap.of());",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMap(identity(), identity(), HashMap::new).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMultimap(identity()).switchIfEmpty(Mono.just(ImmutableMap.of()));",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMultimap(identity(), identity()).defaultIfEmpty(ImmutableMap.of());",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectMultimap(identity(), identity(), HashMap::new).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectSortedList().defaultIfEmpty(ImmutableList.of());",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).collectSortedList((o1, o2) -> 0).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).count().switchIfEmpty(Mono.just(2L));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).elementAt(0).defaultIfEmpty(1);",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).elementAt(0, 2).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).hasElement(2).switchIfEmpty(Mono.just(true));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).hasElements().defaultIfEmpty(true);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).last().single();",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).last(2).switchIfEmpty(Mono.just(3));",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).reduceWith(() -> 0, Integer::sum).defaultIfEmpty(2);",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).single().single();",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).single(2).switchIfEmpty(Mono.just(3));",
+            "",
+            "    Flux.just(1).reduce(Integer::sum).defaultIfEmpty(2);",
+            "    // BUG: Diagnostic contains:",
+            "    Flux.just(1).reduce(2, Integer::sum).single();",
+            "",
+            "    // BUG: Diagnostic contains:",
+            "    Mono.just(1).defaultIfEmpty(1).switchIfEmpty(Mono.just(2));",
+            "    // BUG: Diagnostic contains:",
+            "    Mono.just(1).hasElement().defaultIfEmpty(true);",
+            "    // BUG: Diagnostic contains:",
+            "    Mono.just(1).single().single();",
+            "  }",
+            "}")
+        .doTest();
+  }
+
+  @Test
+  void replacement() {
+    refactoringTestHelper
+        .addInputLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.core.publisher.Mono;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toImmutableList()).single();",
+            "    Flux.just(1).collect(toImmutableList()).defaultIfEmpty(ImmutableList.of());",
+            "    Flux.just(1).collect(toImmutableList()).switchIfEmpty(Mono.just(ImmutableList.of()));",
+            "",
+            "    Mono.just(2).hasElement().single();",
+            "    Mono.just(2).hasElement().defaultIfEmpty(true);",
+            "    Mono.just(2).hasElement().switchIfEmpty(Mono.just(true));",
+            "  }",
+            "}")
+        .addOutputLines(
+            "A.java",
+            "import static com.google.common.collect.ImmutableList.toImmutableList;",
+            "",
+            "import com.google.common.collect.ImmutableList;",
+            "import reactor.core.publisher.Flux;",
+            "import reactor.core.publisher.Mono;",
+            "",
+            "class A {",
+            "  void m() {",
+            "    Flux.just(1).collect(toImmutableList());",
+            "    Flux.just(1).collect(toImmutableList());",
+            "    Flux.just(1).collect(toImmutableList());",
+            "",
+            "    Mono.just(2).hasElement();",
+            "    Mono.just(2).hasElement();",
+            "    Mono.just(2).hasElement();",
+            "  }",
+            "}")
+        .doTest(TEXT_MATCH);
+  }
+}

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

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class PrimitiveComparisonCheckTest {
+final class PrimitiveComparisonTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(PrimitiveComparisonCheck.class, getClass());
+      CompilationTestHelper.newInstance(PrimitiveComparison.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(PrimitiveComparisonCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(PrimitiveComparison.class, getClass());
 
   // XXX: There are no tests for multiple replacements within the same expression:
   // - Error Prone doesn't currently support this, it seems.
@@ -99,10 +99,21 @@ public final class PrimitiveComparisonCheckTest {
             "    cmp().thenComparingDouble(o -> Byte.valueOf((byte) 0));",
             "  }",
             "",
-            "  private Comparator<Object> cmp() { return null; }",
-            "  private byte toPrimitive(Object o) { return 0; }",
-            "  private Byte toBoxed(Object o) { return 0; }",
-            "  private Function<Object, Byte> toBoxed() { return o -> 0; }",
+            "  private Comparator<Object> cmp() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private byte toPrimitive(Object o) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  private Byte toBoxed(Object o) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  private Function<Object, Byte> toBoxed() {",
+            "    return o -> 0;",
+            "  }",
             "}")
         .doTest();
   }
@@ -191,11 +202,25 @@ public final class PrimitiveComparisonCheckTest {
             "    cmp().thenComparingDouble(o -> Integer.valueOf(0));",
             "  }",
             "",
-            "  private Comparator<Object> cmp() { return null; }",
-            "  private int toPrimitive(Object o) { return 0; }",
-            "  private Integer toBoxed(Object o) { return 0; }",
-            "  private Function<Object, Integer> toBoxed() { return o -> 0; }",
-            "  private ToIntFunction<Object> toPrimitive() { return o -> 0; }",
+            "  private Comparator<Object> cmp() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private int toPrimitive(Object o) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  private Integer toBoxed(Object o) {",
+            "    return 0;",
+            "  }",
+            "",
+            "  private Function<Object, Integer> toBoxed() {",
+            "    return o -> 0;",
+            "  }",
+            "",
+            "  private ToIntFunction<Object> toPrimitive() {",
+            "    return o -> 0;",
+            "  }",
             "}")
         .doTest();
   }
@@ -268,11 +293,25 @@ public final class PrimitiveComparisonCheckTest {
             "    cmp().thenComparingDouble(o -> Long.valueOf(0));",
             "  }",
             "",
-            "  private Comparator<Object> cmp() { return null; }",
-            "  private long toPrimitive(Object o) { return 0L; }",
-            "  private Long toBoxed(Object o) { return 0L; }",
-            "  private Function<Object, Long> toBoxed() { return o -> 0L; }",
-            "  private ToLongFunction<Object> toPrimitive() { return o -> 0L; }",
+            "  private Comparator<Object> cmp() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private long toPrimitive(Object o) {",
+            "    return 0L;",
+            "  }",
+            "",
+            "  private Long toBoxed(Object o) {",
+            "    return 0L;",
+            "  }",
+            "",
+            "  private Function<Object, Long> toBoxed() {",
+            "    return o -> 0L;",
+            "  }",
+            "",
+            "  private ToLongFunction<Object> toPrimitive() {",
+            "    return o -> 0L;",
+            "  }",
             "}")
         .doTest();
   }
@@ -326,10 +365,21 @@ public final class PrimitiveComparisonCheckTest {
             "    cmp().thenComparingDouble(o -> Float.valueOf(0));",
             "  }",
             "",
-            "  private Comparator<Object> cmp() { return null; }",
-            "  private float toPrimitive(Object o) { return 0.0f; }",
-            "  private Float toBoxed(Object o) { return 0.0f; }",
-            "  private Function<Object, Float> toBoxed() { return o -> 0.0f; }",
+            "  private Comparator<Object> cmp() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private float toPrimitive(Object o) {",
+            "    return 0.0f;",
+            "  }",
+            "",
+            "  private Float toBoxed(Object o) {",
+            "    return 0.0f;",
+            "  }",
+            "",
+            "  private Function<Object, Float> toBoxed() {",
+            "    return o -> 0.0f;",
+            "  }",
             "}")
         .doTest();
   }
@@ -386,11 +436,25 @@ public final class PrimitiveComparisonCheckTest {
             "    cmp().thenComparingDouble(o -> Double.valueOf(0));",
             "  }",
             "",
-            "  private Comparator<Object> cmp() { return null; }",
-            "  private double toPrimitive(Object o) { return 0.0; }",
-            "  private Double toBoxed(Object o) { return 0.0; }",
-            "  private Function<Object, Double> toBoxed() { return o -> 0.0; }",
-            "  private ToDoubleFunction<Object> toPrimitive() { return o -> 0.0; }",
+            "  private Comparator<Object> cmp() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private double toPrimitive(Object o) {",
+            "    return 0.0;",
+            "  }",
+            "",
+            "  private Double toBoxed(Object o) {",
+            "    return 0.0;",
+            "  }",
+            "",
+            "  private Function<Object, Double> toBoxed() {",
+            "    return o -> 0.0;",
+            "  }",
+            "",
+            "  private ToDoubleFunction<Object> toPrimitive() {",
+            "    return o -> 0.0;",
+            "  }",
             "}")
         .doTest();
   }
@@ -420,8 +484,13 @@ public final class PrimitiveComparisonCheckTest {
             "    cmp().thenComparing(toStr(), cmp());",
             "  }",
             "",
-            "  private Comparator<Object> cmp() { return null; }",
-            "  private Function<Object, String> toStr() { return String::valueOf; }",
+            "  private Comparator<Object> cmp() {",
+            "    return null;",
+            "  }",
+            "",
+            "  private Function<Object, String> toStr() {",
+            "    return String::valueOf;",
+            "  }",
             "}")
         .doTest();
   }
@@ -692,22 +761,30 @@ public final class PrimitiveComparisonCheckTest {
             "import java.util.Comparator;",
             "",
             "interface A extends Comparable<A> {",
-            "  Comparator<A> bCmp = Comparator.<A, A>comparing(o -> o).thenComparingInt(o -> Byte.valueOf((byte) 0));",
-            "  Comparator<A> cCmp = Comparator.<A, A>comparing(o -> o).thenComparingInt(o -> Character.valueOf((char) 0));",
-            "  Comparator<A> sCmp = Comparator.<A, A>comparing(o -> o).thenComparingInt(o -> Short.valueOf((short) 0));",
+            "  Comparator<A> bCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparingInt(o -> Byte.valueOf((byte) 0));",
+            "  Comparator<A> cCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparingInt(o -> Character.valueOf((char) 0));",
+            "  Comparator<A> sCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparingInt(o -> Short.valueOf((short) 0));",
             "  Comparator<A> iCmp = Comparator.<A, A>comparing(o -> o).thenComparingInt(o -> Integer.valueOf(0));",
             "  Comparator<A> lCmp = Comparator.<A, A>comparing(o -> o).thenComparingLong(o -> Long.valueOf(0));",
-            "  Comparator<A> fCmp = Comparator.<A, A>comparing(o -> o).thenComparingDouble(o -> Float.valueOf(0));",
-            "  Comparator<A> dCmp = Comparator.<A, A>comparing(o -> o).thenComparingDouble(o -> Double.valueOf(0));",
+            "  Comparator<A> fCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparingDouble(o -> Float.valueOf(0));",
+            "  Comparator<A> dCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparingDouble(o -> Double.valueOf(0));",
             "}")
         .addOutputLines(
             "out/A.java",
             "import java.util.Comparator;",
             "",
             "interface A extends Comparable<A> {",
-            "  Comparator<A> bCmp = Comparator.<A, A>comparing(o -> o).thenComparing(o -> Byte.valueOf((byte) 0));",
-            "  Comparator<A> cCmp = Comparator.<A, A>comparing(o -> o).thenComparing(o -> Character.valueOf((char) 0));",
-            "  Comparator<A> sCmp = Comparator.<A, A>comparing(o -> o).thenComparing(o -> Short.valueOf((short) 0));",
+            "  Comparator<A> bCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparing(o -> Byte.valueOf((byte) 0));",
+            "  Comparator<A> cCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparing(o -> Character.valueOf((char) 0));",
+            "  Comparator<A> sCmp =",
+            "      Comparator.<A, A>comparing(o -> o).thenComparing(o -> Short.valueOf((short) 0));",
             "  Comparator<A> iCmp = Comparator.<A, A>comparing(o -> o).thenComparing(o -> Integer.valueOf(0));",
             "  Comparator<A> lCmp = Comparator.<A, A>comparing(o -> o).thenComparing(o -> Long.valueOf(0));",
             "  Comparator<A> fCmp = Comparator.<A, A>comparing(o -> o).thenComparing(o -> Float.valueOf(0));",

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

@@ -9,16 +9,16 @@ import org.junit.jupiter.api.Test;
 // XXX: The tests below show that `String.valueOf((String) null)` may be simplified, but
 // `String.valueOf(null)` may not. That is because the latter matches `String#valueOf(char[])`. We
 // could special-case `null` arguments, but that doesn't seem worth the trouble.
-public final class RedundantStringConversionCheckTest {
+final class RedundantStringConversionTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(RedundantStringConversionCheck.class, getClass());
+      CompilationTestHelper.newInstance(RedundantStringConversion.class, getClass());
   private final CompilationTestHelper customizedCompilationTestHelper =
-      CompilationTestHelper.newInstance(RedundantStringConversionCheck.class, getClass())
+      CompilationTestHelper.newInstance(RedundantStringConversion.class, getClass())
           .setArgs(
               ImmutableList.of(
                   "-XepOpt:RedundantStringConversion:ExtraConversionMethods=java.lang.Enum#name(),A#name(),A.B#toString(int)"));
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(RedundantStringConversionCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(RedundantStringConversion.class, getClass());
 
   @Test
   void identificationOfIdentityTransformation() {
@@ -69,9 +69,14 @@ public final class RedundantStringConversionCheckTest {
             "    // BUG: Diagnostic contains:",
             "    s += String.valueOf(i);",
             "    // BUG: Diagnostic contains:",
+            "    s += String.valueOf(0);",
+            "    // BUG: Diagnostic contains:",
             "    s += String.valueOf((String) null);",
             "    s += String.valueOf(null);",
             "    s += String.valueOf(new char[0]);",
+            "    s += String.valueOf(new char[0], 0, 0);",
+            "    // BUG: Diagnostic contains:",
+            "    s += Boolean.toString(false);",
             "    // BUG: Diagnostic contains:",
             "    s += Byte.toString((byte) 0);",
             "    // BUG: Diagnostic contains:",
@@ -121,10 +126,13 @@ public final class RedundantStringConversionCheckTest {
             "      // BUG: Diagnostic contains:",
             "      s + String.valueOf(i),",
             "      // BUG: Diagnostic contains:",
+            "      s + String.valueOf(0),",
+            "      // BUG: Diagnostic contains:",
             "      s + String.valueOf((String) null),",
             "      s + String.valueOf(null),",
             "      s + String.valueOf(new char[0]),",
-            "",
+            "      s + String.valueOf(new char[0], 0, 0),",
+            "      //",
             "      42 + this.toString(),",
             "      42 + super.toString(),",
             "      42 + i.toString(),",
@@ -134,6 +142,7 @@ public final class RedundantStringConversionCheckTest {
             "      42 + String.valueOf((String) null),",
             "      42 + String.valueOf(null),",
             "      42 + String.valueOf(new char[0]),",
+            "      42 + String.valueOf(new char[0], 0, 0),",
             "",
             "      // BUG: Diagnostic contains:",
             "      this.toString() + s,",
@@ -144,19 +153,24 @@ public final class RedundantStringConversionCheckTest {
             "      // BUG: Diagnostic contains:",
             "      String.valueOf(i) + s,",
             "      // BUG: Diagnostic contains:",
+            "      String.valueOf(0) + s,",
+            "      // BUG: Diagnostic contains:",
             "      String.valueOf((String) null) + s,",
             "      String.valueOf(null) + s,",
             "      String.valueOf(new char[0]) + s,",
-            "",
+            "      String.valueOf(new char[0], 0, 0) + s,",
+            "      //",
             "      this.toString() + 42,",
             "      super.toString() + 42,",
             "      i.toString() + 42,",
             "      i.toString(16) + 42,",
             "      String.valueOf(i) + 42,",
+            "      String.valueOf(0) + 42,",
             "      // BUG: Diagnostic contains:",
             "      String.valueOf((String) null) + 42,",
             "      String.valueOf(null) + 42,",
             "      String.valueOf(new char[0]) + 42,",
+            "      String.valueOf(new char[0], 0, 0) + 42,",
             "",
             "      // BUG: Diagnostic contains:",
             "      this.toString() + this.toString(),",
@@ -167,18 +181,18 @@ public final class RedundantStringConversionCheckTest {
             "      // BUG: Diagnostic contains:",
             "      String.valueOf(i) + String.valueOf(i),",
             "      // BUG: Diagnostic contains:",
+            "      String.valueOf(0) + String.valueOf(0),",
+            "      // BUG: Diagnostic contains:",
             "      String.valueOf((String) null) + String.valueOf((String) null),",
             "      String.valueOf(null) + String.valueOf(null),",
             "      String.valueOf(new char[0]) + String.valueOf(new char[0]),",
+            "      String.valueOf(new char[0], 0, 0) + String.valueOf(new char[0], 0, 0),",
             "    };",
             "  }",
             "",
             "  int[] m2() {",
             "    return new int[] {",
-            "      1 + 1,",
-            "      1 - 1,",
-            "      1 * 1,",
-            "      1 / 1,",
+            "      1 + 1, 1 - 1, 1 * 1, 1 / 1,",
             "    };",
             "  }",
             "}")
@@ -207,9 +221,12 @@ public final class RedundantStringConversionCheckTest {
             "    // BUG: Diagnostic contains:",
             "    sb.append(String.valueOf(i));",
             "    // BUG: Diagnostic contains:",
+            "    sb.append(String.valueOf(0));",
+            "    // BUG: Diagnostic contains:",
             "    sb.append(String.valueOf((String) null));",
             "    sb.append(String.valueOf(null));",
             "    sb.append(String.valueOf(new char[0]));",
+            "    sb.append(String.valueOf(new char[0], 0, 0));",
             "    sb.append(s);",
             "    sb.append(\"constant\");",
             "",
@@ -221,9 +238,12 @@ public final class RedundantStringConversionCheckTest {
             "    // BUG: Diagnostic contains:",
             "    sb.insert(0, String.valueOf(i));",
             "    // BUG: Diagnostic contains:",
+            "    sb.insert(0, String.valueOf(0));",
+            "    // BUG: Diagnostic contains:",
             "    sb.insert(0, String.valueOf((String) null));",
             "    sb.insert(0, String.valueOf(null));",
             "    sb.insert(0, String.valueOf(new char[0]));",
+            "    sb.insert(0, String.valueOf(new char[0], 0, 0));",
             "    sb.insert(0, s);",
             "    sb.insert(0, \"constant\");",
             "",
@@ -284,9 +304,9 @@ public final class RedundantStringConversionCheckTest {
     compilationTestHelper
         .addSourceLines(
             "A.java",
-            "import static com.google.common.base.Preconditions.checkState;",
             "import static com.google.common.base.Preconditions.checkArgument;",
             "import static com.google.common.base.Preconditions.checkNotNull;",
+            "import static com.google.common.base.Preconditions.checkState;",
             "import static com.google.common.base.Verify.verify;",
             "import static com.google.common.base.Verify.verifyNotNull;",
             "",
@@ -437,6 +457,8 @@ public final class RedundantStringConversionCheckTest {
             "      // BUG: Diagnostic contains:",
             "      s + String.valueOf(b),",
             "      // BUG: Diagnostic contains:",
+            "      s + Boolean.toString(false),",
+            "      // BUG: Diagnostic contains:",
             "      s + Byte.toString((byte) 0),",
             "      // BUG: Diagnostic contains:",
             "      s + Character.toString((char) 0),",

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

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class RefasterAnyOfUsageCheckTest {
+final class RefasterAnyOfUsageTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(RefasterAnyOfUsageCheck.class, getClass());
+      CompilationTestHelper.newInstance(RefasterAnyOfUsage.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(RefasterAnyOfUsageCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(RefasterAnyOfUsage.class, getClass());
 
   @Test
   void identification() {

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

@@ -1,191 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.common.collect.ImmutableSetMultimap.toImmutableSetMultimap;
-import static java.util.function.Function.identity;
-import static java.util.function.Predicate.not;
-import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatCode;
-import static org.junit.jupiter.params.provider.Arguments.arguments;
-
-import com.google.common.collect.ImmutableSet;
-import com.google.common.collect.ImmutableSetMultimap;
-import com.google.errorprone.BugCheckerRefactoringTestHelper;
-import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
-import java.util.regex.Pattern;
-import java.util.stream.Stream;
-import org.junit.jupiter.api.Test;
-import org.junit.jupiter.params.ParameterizedTest;
-import org.junit.jupiter.params.provider.Arguments;
-import org.junit.jupiter.params.provider.MethodSource;
-
-public final class RefasterCheckTest {
-  /** The names of all Refaster template groups defined in this module. */
-  private static final ImmutableSet<String> TEMPLATE_GROUPS =
-      ImmutableSet.of(
-          "AssertJ",
-          "AssertJBigDecimal",
-          "AssertJBigInteger",
-          "AssertJBoolean",
-          "AssertJByte",
-          "AssertJCharSequence",
-          "AssertJDouble",
-          "AssertJEnumerable",
-          "AssertJFloat",
-          "AssertJInteger",
-          "AssertJLong",
-          "AssertJNumber",
-          "AssertJMap",
-          "AssertJObject",
-          "AssertJOptional",
-          "AssertJShort",
-          "AssertJString",
-          "AssertJThrowingCallable",
-          "Assorted",
-          "BigDecimal",
-          "Collection",
-          "Comparator",
-          "DoubleStream",
-          "Equality",
-          "ImmutableList",
-          "ImmutableListMultimap",
-          "ImmutableMap",
-          "ImmutableMultiset",
-          "ImmutableSet",
-          "ImmutableSetMultimap",
-          "ImmutableSortedMap",
-          "ImmutableSortedMultiset",
-          "ImmutableSortedSet",
-          "IntStream",
-          "JUnit",
-          "LongStream",
-          "MapEntry",
-          "Mockito",
-          "Multimap",
-          "Null",
-          "Optional",
-          "Primitive",
-          "Reactor",
-          "RxJava2Adapter",
-          "Stream",
-          "String",
-          "TestNGToAssertJ",
-          "Time",
-          "WebClient");
-  /**
-   * Matches the parts of the fully-qualified name of a template class that should be removed in
-   * order to produce the associated {@link #TEMPLATE_GROUPS template group name}.
-   */
-  private static final Pattern TEMPLATE_FQCN_TRIM_FOR_GROUP_NAME =
-      Pattern.compile(".*\\.|Templates\\$.*");
-  /**
-   * A mapping from template group names to associated template names.
-   *
-   * <p>In effect, the values correspond to nested classes that represent individual Refaster
-   * templates, while the keys correspond to the associated top-level "aggregator" classes.
-   */
-  private static final ImmutableSetMultimap<String, String> TEMPLATES_BY_GROUP =
-      indexTemplateNamesByGroup(RefasterCheck.ALL_CODE_TRANSFORMERS.get().keySet());
-
-  /** Returns every known template group name as a parameterized test argument. */
-  @SuppressWarnings("UnusedMethod" /* Used as a `@MethodSource`. */)
-  private static Stream<Arguments> templateGroupsUnderTest() {
-    // XXX: Drop the filter once we have added tests for AssertJ!
-    return TEMPLATES_BY_GROUP.keySet().stream().filter(not("AssertJ"::equals)).map(Arguments::of);
-  }
-
-  /**
-   * Returns every known (template group name, template name) pair as a parameterized test argument.
-   */
-  @SuppressWarnings("UnusedMethod" /* Used as a `@MethodSource`. */)
-  private static Stream<Arguments> templatesUnderTest() {
-    // XXX: Drop the filter once we have added tests for AssertJ!
-    return TEMPLATES_BY_GROUP.entries().stream()
-        .filter(e -> !"AssertJ".equals(e.getKey()))
-        .map(e -> arguments(e.getKey(), e.getValue()));
-  }
-
-  /**
-   * Verifies that {@link RefasterCheck#loadAllCodeTransformers} finds at least one code transformer
-   * for all of the {@link #TEMPLATE_GROUPS}.
-   *
-   * <p>This test is just as much about ensuring that {@link #TEMPLATE_GROUPS} is exhaustive, so
-   * that in turn {@link #replacement}'s coverage is exhaustive.
-   */
-  @Test
-  void loadAllCodeTransformers() {
-    assertThat(TEMPLATES_BY_GROUP.keySet()).hasSameElementsAs(TEMPLATE_GROUPS);
-  }
-
-  /**
-   * Verifies for each of the {@link #TEMPLATE_GROUPS} that the associated code transformers have
-   * the desired effect.
-   */
-  @MethodSource("templateGroupsUnderTest")
-  @ParameterizedTest
-  void replacement(String group) {
-    verifyRefactoring(group, namePattern(group));
-  }
-
-  /**
-   * Verifies that all loaded Refaster templates are covered by at least one test.
-   *
-   * <p>Note that this doesn't guarantee full coverage: this test cannot ascertain that all {@link
-   * com.google.errorprone.refaster.Refaster#anyOf} branches are tested. Idem for {@link
-   * com.google.errorprone.refaster.annotation.BeforeTemplate} methods in case there are multiple .
-   */
-  @MethodSource("templatesUnderTest")
-  @ParameterizedTest
-  void coverage(String group, String template) {
-    assertThatCode(() -> verifyRefactoring(group, namePattern(group, template)))
-        .withFailMessage(
-            "Template %s does not affect the tests for group %s; is it tested?", template, group)
-        .isInstanceOf(AssertionError.class)
-        .hasMessageFindingMatch("^(diff|expected):");
-  }
-
-  private static ImmutableSetMultimap<String, String> indexTemplateNamesByGroup(
-      ImmutableSet<String> templateNames) {
-    return templateNames.stream()
-        .collect(
-            toImmutableSetMultimap(
-                n -> TEMPLATE_FQCN_TRIM_FOR_GROUP_NAME.matcher(n).replaceAll(""), identity()));
-  }
-
-  private static String namePattern(String groupName, String excludedTemplate) {
-    return "(?!" + Pattern.quote(excludedTemplate) + ')' + namePattern(groupName);
-  }
-
-  private static String namePattern(String groupName) {
-    return Pattern.compile(Pattern.quote(groupName)) + "Templates.*";
-  }
-
-  private void verifyRefactoring(String groupName, String templateNamePattern) {
-    createRestrictedRefactoringTestHelper(templateNamePattern)
-        .addInput(groupName + "TemplatesTestInput.java")
-        .addOutput(groupName + "TemplatesTestOutput.java")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-
-  private BugCheckerRefactoringTestHelper createRestrictedRefactoringTestHelper(
-      String namePattern) {
-    return BugCheckerRefactoringTestHelper.newInstance(
-            RefasterCheck.class, getRefasterTemplateCollectionClass())
-        .setArgs("-XepOpt:Refaster:NamePattern=" + namePattern);
-  }
-
-  /**
-   * Returns an arbitrary Refaster template collection class inside the {@code
-   * tech.picnic.errorprone.refastertemplates} package, enabling {@link
-   * BugCheckerRefactoringTestHelper} to load test resources from said package.
-   */
-  private Class<?> getRefasterTemplateCollectionClass() {
-    try {
-      return Class.forName(
-          "tech.picnic.errorprone.refastertemplates.AssortedTemplates",
-          /* initialize= */ false,
-          getClass().getClassLoader());
-    } catch (ClassNotFoundException e) {
-      throw new IllegalStateException("Failed to load Refaster template collection class", e);
-    }
-  }
-}

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

@@ -1,86 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import com.google.errorprone.CompilationTestHelper;
-import org.junit.jupiter.api.Test;
-
-final class RequestMappingAnnotationCheckTest {
-  private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(RequestMappingAnnotationCheck.class, getClass());
-
-  @Test
-  void identification() {
-    compilationTestHelper
-        .addSourceLines(
-            "A.java",
-            "import java.io.InputStream;",
-            "import java.time.ZoneId;",
-            "import java.util.Locale;",
-            "import java.util.TimeZone;",
-            "import javax.servlet.http.HttpServletRequest;",
-            "import javax.servlet.http.HttpServletResponse;",
-            "import org.springframework.http.HttpMethod;",
-            "import org.springframework.web.bind.annotation.DeleteMapping;",
-            "import org.springframework.web.bind.annotation.GetMapping;",
-            "import org.springframework.web.bind.annotation.PatchMapping;",
-            "import org.springframework.web.bind.annotation.PathVariable;",
-            "import org.springframework.web.bind.annotation.PostMapping;",
-            "import org.springframework.web.bind.annotation.PutMapping;",
-            "import org.springframework.web.bind.annotation.RequestBody;",
-            "import org.springframework.web.bind.annotation.RequestHeader;",
-            "import org.springframework.web.bind.annotation.RequestMapping;",
-            "import org.springframework.web.bind.annotation.RequestMethod;",
-            "import org.springframework.web.bind.annotation.RequestParam;",
-            "import org.springframework.web.context.request.NativeWebRequest;",
-            "import org.springframework.web.context.request.WebRequest;",
-            "import org.springframework.web.server.ServerWebExchange;",
-            "import org.springframework.web.util.UriBuilder;",
-            "import org.springframework.web.util.UriComponentsBuilder;",
-            "",
-            "interface A {",
-            "  A noMapping();",
-            "  A noMapping(String param);",
-            "  @DeleteMapping A properNoParameters();",
-            "  @GetMapping A properPathVariable(@PathVariable String param);",
-            "  @PatchMapping A properRequestBody(@RequestBody String body);",
-            "  @PostMapping A properRequestHeader(@RequestHeader String header);",
-            "  @PutMapping A properRequestParam(@RequestParam String param);",
-            "  @RequestMapping A properInputStream(InputStream input);",
-            "  @RequestMapping A properZoneId(ZoneId zoneId);",
-            "  @RequestMapping A properLocale(Locale locale);",
-            "  @RequestMapping A properTimeZone(TimeZone timeZone);",
-            "  @RequestMapping A properHttpServletRequest(HttpServletRequest request);",
-            "  @RequestMapping A properHttpServletResponse(HttpServletResponse response);",
-            "  @RequestMapping A properHttpMethod(HttpMethod method);",
-            "  @RequestMapping A properNativeWebRequest(NativeWebRequest request);",
-            "  @RequestMapping A properWebRequest(WebRequest request);",
-            "  @RequestMapping A properServerWebExchange(ServerWebExchange exchange);",
-            "  @RequestMapping A properServerUriBuilder(UriBuilder builder);",
-            "  @RequestMapping A properServerUriComponentsBuilder(UriComponentsBuilder builder);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @DeleteMapping A delete(String param);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @GetMapping A get(String param);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @PatchMapping A patch(String param);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @PostMapping A post(String param);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @PutMapping A put(String param);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @RequestMapping A requestMultiple(String param, String param2);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @RequestMapping A requestFirstParamViolation(String param, @PathVariable String param2);",
-            "",
-            "  // BUG: Diagnostic contains:",
-            "  @RequestMapping A requestSecondParamViolation(@RequestBody String param, String param2);",
-            "}")
-        .doTest();
-  }
-}

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

@@ -0,0 +1,136 @@
+package tech.picnic.errorprone.bugpatterns;
+
+import com.google.errorprone.CompilationTestHelper;
+import org.junit.jupiter.api.Test;
+
+final class RequestMappingAnnotationTest {
+  private final CompilationTestHelper compilationTestHelper =
+      CompilationTestHelper.newInstance(RequestMappingAnnotation.class, getClass());
+
+  @Test
+  void identification() {
+    compilationTestHelper
+        .addSourceLines(
+            "A.java",
+            "import java.io.InputStream;",
+            "import java.time.ZoneId;",
+            "import java.util.Locale;",
+            "import java.util.TimeZone;",
+            "import javax.servlet.http.HttpServletRequest;",
+            "import javax.servlet.http.HttpServletResponse;",
+            "import org.springframework.http.HttpMethod;",
+            "import org.springframework.web.bind.annotation.DeleteMapping;",
+            "import org.springframework.web.bind.annotation.GetMapping;",
+            "import org.springframework.web.bind.annotation.PatchMapping;",
+            "import org.springframework.web.bind.annotation.PathVariable;",
+            "import org.springframework.web.bind.annotation.PostMapping;",
+            "import org.springframework.web.bind.annotation.PutMapping;",
+            "import org.springframework.web.bind.annotation.RequestAttribute;",
+            "import org.springframework.web.bind.annotation.RequestBody;",
+            "import org.springframework.web.bind.annotation.RequestHeader;",
+            "import org.springframework.web.bind.annotation.RequestMapping;",
+            "import org.springframework.web.bind.annotation.RequestParam;",
+            "import org.springframework.web.bind.annotation.RequestPart;",
+            "import org.springframework.web.context.request.NativeWebRequest;",
+            "import org.springframework.web.context.request.WebRequest;",
+            "import org.springframework.web.server.ServerWebExchange;",
+            "import org.springframework.web.util.UriBuilder;",
+            "import org.springframework.web.util.UriComponentsBuilder;",
+            "",
+            "interface A {",
+            "  A noMapping();",
+            "",
+            "  A noMapping(String param);",
+            "",
+            "  @DeleteMapping",
+            "  A properNoParameters();",
+            "",
+            "  @GetMapping",
+            "  A properPathVariable(@PathVariable String param);",
+            "",
+            "  @PatchMapping",
+            "  A properRequestAttribute(@RequestAttribute String attribute);",
+            "",
+            "  @PostMapping",
+            "  A properRequestBody(@RequestBody String body);",
+            "",
+            "  @PutMapping",
+            "  A properRequestHeader(@RequestHeader String header);",
+            "",
+            "  @RequestMapping",
+            "  A properRequestParam(@RequestParam String param);",
+            "",
+            "  @RequestMapping",
+            "  A properRequestPart(@RequestPart String part);",
+            "",
+            "  @RequestMapping",
+            "  A properInputStream(InputStream input);",
+            "",
+            "  @RequestMapping",
+            "  A properZoneId(ZoneId zoneId);",
+            "",
+            "  @RequestMapping",
+            "  A properLocale(Locale locale);",
+            "",
+            "  @RequestMapping",
+            "  A properTimeZone(TimeZone timeZone);",
+            "",
+            "  @RequestMapping",
+            "  A properHttpServletRequest(HttpServletRequest request);",
+            "",
+            "  @RequestMapping",
+            "  A properHttpServletResponse(HttpServletResponse response);",
+            "",
+            "  @RequestMapping",
+            "  A properHttpMethod(HttpMethod method);",
+            "",
+            "  @RequestMapping",
+            "  A properNativeWebRequest(NativeWebRequest request);",
+            "",
+            "  @RequestMapping",
+            "  A properWebRequest(WebRequest request);",
+            "",
+            "  @RequestMapping",
+            "  A properServerWebExchange(ServerWebExchange exchange);",
+            "",
+            "  @RequestMapping",
+            "  A properServerUriBuilder(UriBuilder builder);",
+            "",
+            "  @RequestMapping",
+            "  A properServerUriComponentsBuilder(UriComponentsBuilder builder);",
+            "",
+            "  @DeleteMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A delete(String param);",
+            "",
+            "  @GetMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A get(String param);",
+            "",
+            "  @PatchMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A patch(String param);",
+            "",
+            "  @PostMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A post(String param);",
+            "",
+            "  @PutMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A put(String param);",
+            "",
+            "  @RequestMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A requestMultiple(String param, String param2);",
+            "",
+            "  @RequestMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A requestFirstParamViolation(String param, @PathVariable String param2);",
+            "",
+            "  @RequestMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A requestSecondParamViolation(@RequestBody String param, String param2);",
+            "}")
+        .doTest();
+  }
+}

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

@@ -3,9 +3,9 @@ package tech.picnic.errorprone.bugpatterns;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-final class RequestParamTypeCheckTest {
+final class RequestParamTypeTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(RequestParamTypeCheck.class, getClass());
+      CompilationTestHelper.newInstance(RequestParamType.class, getClass());
 
   @Test
   void identification() {
@@ -28,23 +28,36 @@ final class RequestParamTypeCheckTest {
             "import org.springframework.web.bind.annotation.RequestParam;",
             "",
             "interface A {",
-            "  @PostMapping A properRequestParam(@RequestBody String body);",
-            "  @GetMapping A properRequestParam(@RequestParam int param);",
-            "  @GetMapping A properRequestParam(@RequestParam List<String> param);",
-            "  @PostMapping A properRequestParam(@RequestBody String body, @RequestParam Set<String> param);",
-            "  @PutMapping A properRequestParam(@RequestBody String body, @RequestParam Map<String, String> param);",
+            "  @PostMapping",
+            "  A properRequestParam(@RequestBody String body);",
             "",
-            "  // BUG: Diagnostic contains:",
-            "  @GetMapping A get(@RequestParam ImmutableBiMap<String, String> param);",
+            "  @GetMapping",
+            "  A properRequestParam(@RequestParam int param);",
             "",
-            "  // BUG: Diagnostic contains:",
-            "  @PostMapping A post(@Nullable @RequestParam ImmutableList<String> param);",
+            "  @GetMapping",
+            "  A properRequestParam(@RequestParam List<String> param);",
             "",
-            "  // BUG: Diagnostic contains:",
-            "  @PutMapping A put(@RequestBody String body, @RequestParam ImmutableSet<String> param);",
+            "  @PostMapping",
+            "  A properRequestParam(@RequestBody String body, @RequestParam Set<String> param);",
             "",
+            "  @PutMapping",
+            "  A properRequestParam(@RequestBody String body, @RequestParam Map<String, String> param);",
+            "",
+            "  @GetMapping",
             "  // BUG: Diagnostic contains:",
-            "  @DeleteMapping A delete(@RequestBody String body, @RequestParam ImmutableMap<String, String> param);",
+            "  A get(@RequestParam ImmutableBiMap<String, String> param);",
+            "",
+            "  @PostMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A post(@Nullable @RequestParam ImmutableList<String> param);",
+            "",
+            "  @PutMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A put(@RequestBody String body, @RequestParam ImmutableSet<String> param);",
+            "",
+            "  @DeleteMapping",
+            "  // BUG: Diagnostic contains:",
+            "  A delete(@RequestBody String body, @RequestParam ImmutableMap<String, String> param);",
             "",
             "  void negative(ImmutableSet<Integer> set, ImmutableMap<String, String> map);",
             "}")

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

@@ -4,14 +4,12 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
-import org.junit.jupiter.api.condition.DisabledForJreRange;
-import org.junit.jupiter.api.condition.JRE;
 
-public final class ScheduledTransactionTraceCheckTest {
+final class ScheduledTransactionTraceTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(ScheduledTransactionTraceCheck.class, getClass());
+      CompilationTestHelper.newInstance(ScheduledTransactionTrace.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(ScheduledTransactionTraceCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(ScheduledTransactionTrace.class, getClass());
 
   @Test
   void identification() {
@@ -45,10 +43,7 @@ public final class ScheduledTransactionTraceCheckTest {
         .doTest();
   }
 
-  // XXX: Enable this test for all JREs once https://github.com/google/error-prone/pull/2820 is
-  // merged and released.
   @Test
-  @DisabledForJreRange(min = JRE.JAVA_12)
   void replacement() {
     refactoringTestHelper
         .addInputLines(

error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/Slf4JLogStatementTest.java

@@ -5,11 +5,11 @@ import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.jupiter.api.Test;
 
-public final class Slf4jLogStatementCheckTest {
+final class Slf4JLogStatementTest {
   private final CompilationTestHelper compilationTestHelper =
-      CompilationTestHelper.newInstance(Slf4jLogStatementCheck.class, getClass());
+      CompilationTestHelper.newInstance(Slf4jLogStatement.class, getClass());
   private final BugCheckerRefactoringTestHelper refactoringTestHelper =
-      BugCheckerRefactoringTestHelper.newInstance(Slf4jLogStatementCheck.class, getClass());
+      BugCheckerRefactoringTestHelper.newInstance(Slf4jLogStatement.class, getClass());
 
   @Test
   void identification() {
@@ -44,7 +44,8 @@ public final class Slf4jLogStatementCheckTest {
             "    LOG.info(marker, s, o, t);",
             "",
             "    LOG.warn(FMT0);",
-            "    // BUG: Diagnostic contains: Log statement contains 0 placeholders, but specifies 1 matching argument(s)",
+            "    // BUG: Diagnostic contains: Log statement contains 0 placeholders, but specifies 1 matching",
+            "    // argument(s)",
             "    LOG.error(FMT0, o);",
             "    LOG.trace(FMT0, t);",
             "    // BUG: Diagnostic contains:",
@@ -56,13 +57,15 @@ public final class Slf4jLogStatementCheckTest {
             "    // BUG: Diagnostic contains:",
             "    LOG.trace(marker, FMT0, o, t);",
             "",
-            "    // BUG: Diagnostic contains: Log statement contains 1 placeholders, but specifies 0 matching argument(s)",
+            "    // BUG: Diagnostic contains: Log statement contains 1 placeholders, but specifies 0 matching",
+            "    // argument(s)",
             "    LOG.debug(FMT1);",
             "    LOG.info(FMT1, o);",
             "    // BUG: Diagnostic contains:",
             "    LOG.warn(FMT1, t);",
             "    LOG.error(FMT1, o, t);",
-            "    // BUG: Diagnostic contains: Log statement contains 1 placeholders, but specifies 2 matching argument(s)",
+            "    // BUG: Diagnostic contains: Log statement contains 1 placeholders, but specifies 2 matching",
+            "    // argument(s)",
             "    LOG.trace(FMT1, o, o);",
             "    // BUG: Diagnostic contains:",
             "    LOG.debug(FMT1, o, o, t);",