diff --git a/error-prone-contrib/pom.xml b/error-prone-contrib/pom.xml
index a7a42151..d405b73b 100644
--- a/error-prone-contrib/pom.xml
+++ b/error-prone-contrib/pom.xml
@@ -126,6 +126,11 @@
             <artifactId>jakarta.servlet-api</artifactId>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>javax.inject</groupId>
+            <artifactId>javax.inject</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>javax.xml.bind</groupId>
             <artifactId>jaxb-api</artifactId>
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationAttributeListing.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationAttributeListing.java
index bd346140..ad46c265 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationAttributeListing.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/LexicographicalAnnotationAttributeListing.java
@@ -40,6 +40,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Stream;
+import javax.inject.Inject;
 import org.jspecify.annotations.Nullable;
 import tech.picnic.errorprone.bugpatterns.util.AnnotationAttributeMatcher;
 import tech.picnic.errorprone.bugpatterns.util.Flags;
@@ -94,7 +95,8 @@ public final class LexicographicalAnnotationAttributeListing extends BugChecker
    *
    * @param flags Any provided command line flags.
    */
-  public LexicographicalAnnotationAttributeListing(ErrorProneFlags flags) {
+  @Inject
+  LexicographicalAnnotationAttributeListing(ErrorProneFlags flags) {
     matcher = createAnnotationAttributeMatcher(flags);
   }
 
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java
index db4889a9..8ea3f7ad 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RedundantStringConversion.java
@@ -50,6 +50,7 @@ import java.util.Locale;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.stream.Stream;
+import javax.inject.Inject;
 import tech.picnic.errorprone.bugpatterns.util.Flags;
 import tech.picnic.errorprone.bugpatterns.util.MethodMatcherFactory;
 import tech.picnic.errorprone.bugpatterns.util.SourceCode;
@@ -155,7 +156,8 @@ public final class RedundantStringConversion extends BugChecker
    *
    * @param flags Any provided command line flags.
    */
-  public RedundantStringConversion(ErrorProneFlags flags) {
+  @Inject
+  RedundantStringConversion(ErrorProneFlags flags) {
     conversionMethodMatcher = createConversionMethodMatcher(flags);
   }
 
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamType.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamType.java
index 13143621..045d6ac8 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamType.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/RequestParamType.java
@@ -27,6 +27,7 @@ import com.google.errorprone.matchers.Matcher;
 import com.google.errorprone.suppliers.Suppliers;
 import com.sun.source.tree.Tree;
 import com.sun.source.tree.VariableTree;
+import javax.inject.Inject;
 import tech.picnic.errorprone.bugpatterns.util.Flags;
 
 /** A {@link BugChecker} that flags {@code @RequestParam} parameters with an unsupported type. */
@@ -55,7 +56,8 @@ public final class RequestParamType extends BugChecker implements VariableTreeMa
    *
    * @param flags Any provided command line flags.
    */
-  public RequestParamType(ErrorProneFlags flags) {
+  @Inject
+  RequestParamType(ErrorProneFlags flags) {
     hasUnsupportedRequestParamType = hasUnsupportedRequestParamType(flags);
   }
 
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StringCaseLocaleUsage.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StringCaseLocaleUsage.java
deleted file mode 100644
index 9aa40e01..00000000
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/bugpatterns/StringCaseLocaleUsage.java
+++ /dev/null
@@ -1,89 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import static com.google.errorprone.BugPattern.LinkType.CUSTOM;
-import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
-import static com.google.errorprone.BugPattern.StandardTags.FRAGILE_CODE;
-import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
-import static com.sun.tools.javac.parser.Tokens.TokenKind.RPAREN;
-import static tech.picnic.errorprone.bugpatterns.util.Documentation.BUG_PATTERNS_BASE_URL;
-
-import com.google.auto.service.AutoService;
-import com.google.common.collect.Streams;
-import com.google.errorprone.BugPattern;
-import com.google.errorprone.VisitorState;
-import com.google.errorprone.bugpatterns.BugChecker;
-import com.google.errorprone.bugpatterns.BugChecker.MethodInvocationTreeMatcher;
-import com.google.errorprone.fixes.Fix;
-import com.google.errorprone.fixes.SuggestedFix;
-import com.google.errorprone.matchers.Description;
-import com.google.errorprone.matchers.Matcher;
-import com.google.errorprone.util.ASTHelpers;
-import com.google.errorprone.util.ErrorProneTokens;
-import com.sun.source.tree.ExpressionTree;
-import com.sun.source.tree.MethodInvocationTree;
-import com.sun.tools.javac.util.Position;
-import tech.picnic.errorprone.bugpatterns.util.SourceCode;
-
-/**
- * A {@link BugChecker} that flags calls to {@link String#toLowerCase()} and {@link
- * String#toUpperCase()}, as these methods implicitly rely on the environment's default locale.
- */
-// XXX: Also flag `String::toLowerCase` and `String::toUpperCase` method references. For these cases
-// the suggested fix should introduce a lambda expression with a parameter of which the name does
-// not coincide with the name of an existing variable name. Such functionality should likely be
-// introduced in a utility class.
-@AutoService(BugChecker.class)
-@BugPattern(
-    summary = "Specify a `Locale` when calling `String#to{Lower,Upper}Case`",
-    link = BUG_PATTERNS_BASE_URL + "StringCaseLocaleUsage",
-    linkType = CUSTOM,
-    severity = WARNING,
-    tags = FRAGILE_CODE)
-public final class StringCaseLocaleUsage extends BugChecker implements MethodInvocationTreeMatcher {
-  private static final long serialVersionUID = 1L;
-  private static final Matcher<ExpressionTree> DEFAULT_LOCALE_CASE_CONVERSION =
-      instanceMethod()
-          .onExactClass(String.class.getName())
-          .namedAnyOf("toLowerCase", "toUpperCase")
-          .withNoParameters();
-
-  /** Instantiates a new {@link StringCaseLocaleUsage} instance. */
-  public StringCaseLocaleUsage() {}
-
-  @Override
-  public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {
-    if (!DEFAULT_LOCALE_CASE_CONVERSION.matches(tree, state)) {
-      return Description.NO_MATCH;
-    }
-
-    int closingParenPosition = getClosingParenPosition(tree, state);
-    if (closingParenPosition == Position.NOPOS) {
-      return describeMatch(tree);
-    }
-
-    return buildDescription(tree)
-        .addFix(suggestLocale(closingParenPosition, "Locale.ROOT"))
-        .addFix(suggestLocale(closingParenPosition, "Locale.getDefault()"))
-        .build();
-  }
-
-  private static Fix suggestLocale(int insertPosition, String locale) {
-    return SuggestedFix.builder()
-        .addImport("java.util.Locale")
-        .replace(insertPosition, insertPosition, locale)
-        .build();
-  }
-
-  private static int getClosingParenPosition(MethodInvocationTree tree, VisitorState state) {
-    int startPosition = ASTHelpers.getStartPosition(tree);
-    if (startPosition == Position.NOPOS) {
-      return Position.NOPOS;
-    }
-
-    return Streams.findLast(
-            ErrorProneTokens.getTokens(SourceCode.treeToString(tree, state), state.context).stream()
-                .filter(t -> t.kind() == RPAREN))
-        .map(token -> startPosition + token.pos())
-        .orElse(Position.NOPOS);
-  }
-}
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BugCheckerRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BugCheckerRules.java
index a65dff67..fc3727af 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BugCheckerRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/BugCheckerRules.java
@@ -3,6 +3,7 @@ package tech.picnic.errorprone.refasterrules;
 import com.google.errorprone.BugCheckerRefactoringTestHelper;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChooser;
 import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -25,6 +26,7 @@ final class BugCheckerRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     BugCheckerRefactoringTestHelper after(BugCheckerRefactoringTestHelper helper) {
       return helper;
     }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ComparatorRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ComparatorRules.java
index 51a26592..96504490 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ComparatorRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ComparatorRules.java
@@ -12,6 +12,7 @@ import static java.util.function.Function.identity;
 import com.google.common.collect.Comparators;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -78,6 +79,7 @@ final class ComparatorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     @UseImportPolicy(STATIC_IMPORT_ALWAYS)
     Comparator<T> after(Comparator<T> cmp) {
       return cmp;
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/DoubleStreamRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/DoubleStreamRules.java
index 5e12ce57..409eb1ae 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/DoubleStreamRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/DoubleStreamRules.java
@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.refasterrules;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -27,6 +28,7 @@ final class DoubleStreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     DoubleStream after(DoubleStream stream) {
       return stream;
     }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/EqualityRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/EqualityRules.java
index bb6eb4bb..effd0454 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/EqualityRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/EqualityRules.java
@@ -1,5 +1,6 @@
 package tech.picnic.errorprone.refasterrules;
 
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.AlsoNegation;
@@ -63,6 +64,7 @@ final class EqualityRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     boolean after(boolean b) {
       return b;
     }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/IntStreamRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/IntStreamRules.java
index c49b7741..5ba2ed29 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/IntStreamRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/IntStreamRules.java
@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.refasterrules;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -40,6 +41,7 @@ final class IntStreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     IntStream after(IntStream stream) {
       return stream;
     }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/LongStreamRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/LongStreamRules.java
index bd7edb55..fe3bec81 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/LongStreamRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/LongStreamRules.java
@@ -1,6 +1,7 @@
 package tech.picnic.errorprone.refasterrules;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -40,6 +41,7 @@ final class LongStreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     LongStream after(LongStream stream) {
       return stream;
     }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/OptionalRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/OptionalRules.java
index 87f4ab8d..86fbe125 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/OptionalRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/OptionalRules.java
@@ -3,6 +3,7 @@ package tech.picnic.errorprone.refasterrules;
 import static com.google.errorprone.refaster.ImportPolicy.STATIC_IMPORT_ALWAYS;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -351,6 +352,7 @@ final class OptionalRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Optional<T> after(Optional<T> optional) {
       return optional;
     }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java
index ef0734e2..f7c9d15e 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/ReactorRules.java
@@ -14,6 +14,7 @@ import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -411,6 +412,7 @@ final class ReactorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Mono<T> after(Mono<T> mono) {
       return mono;
     }
@@ -424,6 +426,7 @@ final class ReactorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Flux<T> after(Flux<T> flux) {
       return flux;
     }
@@ -1276,6 +1279,7 @@ final class ReactorRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     StepVerifier.Step<T> after(StepVerifier.Step<T> step) {
       return step;
     }
diff --git a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java
index fdd5f2e7..0cfa9ab3 100644
--- a/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java
+++ b/error-prone-contrib/src/main/java/tech/picnic/errorprone/refasterrules/StreamRules.java
@@ -21,6 +21,7 @@ import static java.util.stream.Collectors.summingInt;
 import static java.util.stream.Collectors.summingLong;
 
 import com.google.common.collect.Streams;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.refaster.Refaster;
 import com.google.errorprone.refaster.annotation.AfterTemplate;
 import com.google.errorprone.refaster.annotation.BeforeTemplate;
@@ -124,6 +125,7 @@ final class StreamRules {
     }
 
     @AfterTemplate
+    @CanIgnoreReturnValue
     Stream<T> after(Stream<T> stream) {
       return stream;
     }
diff --git a/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/StringCaseLocaleUsageTest.java b/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/StringCaseLocaleUsageTest.java
deleted file mode 100644
index a3d087ae..00000000
--- a/error-prone-contrib/src/test/java/tech/picnic/errorprone/bugpatterns/StringCaseLocaleUsageTest.java
+++ /dev/null
@@ -1,124 +0,0 @@
-package tech.picnic.errorprone.bugpatterns;
-
-import com.google.errorprone.BugCheckerRefactoringTestHelper;
-import com.google.errorprone.BugCheckerRefactoringTestHelper.FixChoosers;
-import com.google.errorprone.BugCheckerRefactoringTestHelper.TestMode;
-import com.google.errorprone.CompilationTestHelper;
-import org.junit.jupiter.api.Test;
-
-final class StringCaseLocaleUsageTest {
-  @Test
-  void identification() {
-    CompilationTestHelper.newInstance(StringCaseLocaleUsage.class, getClass())
-        .addSourceLines(
-            "A.java",
-            "import static java.util.Locale.ROOT;",
-            "",
-            "import java.util.Locale;",
-            "",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(Locale.ROOT);",
-            "    \"a\".toUpperCase(Locale.ROOT);",
-            "    \"b\".toLowerCase(ROOT);",
-            "    \"b\".toUpperCase(ROOT);",
-            "    \"c\".toLowerCase(Locale.getDefault());",
-            "    \"c\".toUpperCase(Locale.getDefault());",
-            "    \"d\".toLowerCase(Locale.ENGLISH);",
-            "    \"d\".toUpperCase(Locale.ENGLISH);",
-            "    \"e\".toLowerCase(new Locale(\"foo\"));",
-            "    \"e\".toUpperCase(new Locale(\"foo\"));",
-            "",
-            "    // BUG: Diagnostic contains:",
-            "    \"f\".toLowerCase();",
-            "    // BUG: Diagnostic contains:",
-            "    \"g\".toUpperCase();",
-            "",
-            "    String h = \"h\";",
-            "    // BUG: Diagnostic contains:",
-            "    h.toLowerCase();",
-            "    String i = \"i\";",
-            "    // BUG: Diagnostic contains:",
-            "    i.toUpperCase();",
-            "  }",
-            "}")
-        .doTest();
-  }
-
-  @Test
-  void replacementFirstSuggestedFix() {
-    BugCheckerRefactoringTestHelper.newInstance(StringCaseLocaleUsage.class, getClass())
-        .addInputLines(
-            "A.java",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(/* Comment with parens: (). */ );",
-            "    \"b\".toUpperCase();",
-            "    \"c\".toLowerCase().toString();",
-            "",
-            "    toString().toLowerCase();",
-            "    toString().toUpperCase /* Comment with parens: (). */();",
-            "",
-            "    this.toString().toLowerCase() /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase();",
-            "  }",
-            "}")
-        .addOutputLines(
-            "A.java",
-            "import java.util.Locale;",
-            "",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(/* Comment with parens: (). */ Locale.ROOT);",
-            "    \"b\".toUpperCase(Locale.ROOT);",
-            "    \"c\".toLowerCase(Locale.ROOT).toString();",
-            "",
-            "    toString().toLowerCase(Locale.ROOT);",
-            "    toString().toUpperCase /* Comment with parens: (). */(Locale.ROOT);",
-            "",
-            "    this.toString().toLowerCase(Locale.ROOT) /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase(Locale.ROOT);",
-            "  }",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-
-  @Test
-  void replacementSecondSuggestedFix() {
-    BugCheckerRefactoringTestHelper.newInstance(StringCaseLocaleUsage.class, getClass())
-        .setFixChooser(FixChoosers.SECOND)
-        .addInputLines(
-            "A.java",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase();",
-            "    \"b\".toUpperCase(/* Comment with parens: (). */ );",
-            "    \"c\".toLowerCase().toString();",
-            "",
-            "    toString().toLowerCase();",
-            "    toString().toUpperCase /* Comment with parens: (). */();",
-            "",
-            "    this.toString().toLowerCase() /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase();",
-            "  }",
-            "}")
-        .addOutputLines(
-            "A.java",
-            "import java.util.Locale;",
-            "",
-            "class A {",
-            "  void m() {",
-            "    \"a\".toLowerCase(Locale.getDefault());",
-            "    \"b\".toUpperCase(/* Comment with parens: (). */ Locale.getDefault());",
-            "    \"c\".toLowerCase(Locale.getDefault()).toString();",
-            "",
-            "    toString().toLowerCase(Locale.getDefault());",
-            "    toString().toUpperCase /* Comment with parens: (). */(Locale.getDefault());",
-            "",
-            "    this.toString().toLowerCase(Locale.getDefault()) /* Comment with parens: (). */;",
-            "    this.toString().toUpperCase(Locale.getDefault());",
-            "  }",
-            "}")
-        .doTest(TestMode.TEXT_MATCH);
-  }
-}
diff --git a/pom.xml b/pom.xml
index 6d25a720..94ed687c 100644
--- a/pom.xml
+++ b/pom.xml
@@ -201,7 +201,7 @@
         <version.auto-value>1.10.1</version.auto-value>
         <version.error-prone>${version.error-prone-orig}</version.error-prone>
         <version.error-prone-fork>v${version.error-prone-orig}-picnic-1</version.error-prone-fork>
-        <version.error-prone-orig>2.18.0</version.error-prone-orig>
+        <version.error-prone-orig>2.19.1</version.error-prone-orig>
         <version.error-prone-slf4j>0.1.18</version.error-prone-slf4j>
         <version.guava-beta-checker>1.0</version.guava-beta-checker>
         <version.jdk>11</version.jdk>
@@ -362,6 +362,11 @@
                 <artifactId>jakarta.servlet-api</artifactId>
                 <version>6.0.0</version>
             </dependency>
+            <dependency>
+                <groupId>javax.inject</groupId>
+                <artifactId>javax.inject</artifactId>
+                <version>1</version>
+            </dependency>
             <dependency>
                 <groupId>javax.xml.bind</groupId>
                 <artifactId>jaxb-api</artifactId>
@@ -981,6 +986,17 @@
                                             <ignoreClass>org.checkerframework.dataflow.qual.*</ignoreClass>
                                         </ignoreClasses>
                                     </dependency>
+                                    <dependency>
+                                        <groupId>org.springframework</groupId>
+                                        <artifactId>spring-aop</artifactId>
+                                        <!-- Spring AOP redistributes the AOP
+                                        Alliance interfaces of the
+                                        `aopalliance:aopalliance` artifact. See
+                                        https://jira.spring.io/browse/SPR-13984. -->
+                                        <ignoreClasses>
+                                            <ignoreClass>org.aopalliance.*</ignoreClass>
+                                        </ignoreClasses>
+                                    </dependency>
                                 </dependencies>
                                 <findAllDuplicates>true</findAllDuplicates>
                             </banDuplicateClasses>
@@ -1700,10 +1716,6 @@
                                     <!-- XXX: Enable this once we open-source
                                     this library. -->
                                     -Xep:BetaApi:OFF
-                                    <!-- XXX: Enable once compatible with
-                                    `UnnecessarilyVisible`. See
-                                    https://github.com/google/error-prone/issues/3706. -->
-                                    -Xep:InjectOnBugCheckers:OFF
                                     <!-- We don't target JDK 7. -->
                                     -Xep:Java7ApiChecker:OFF
                                     <!-- We don't target JDK 8. -->
@@ -1724,6 +1736,8 @@
                                     -XepOpt:NullAway:AssertsEnabled=true
                                     -XepOpt:NullAway:CheckOptionalEmptiness=true
                                     -XepOpt:Nullness:Conservative=false
+                                    -XepOpt:StatementSwitchToExpressionSwitch:EnableAssignmentSwitchConversion=true
+                                    -XepOpt:StatementSwitchToExpressionSwitch:EnableReturnSwitchConversion=true
                                     <!-- XXX: Enable once this check respects
                                     the compilation source version. See
                                     https://github.com/google/error-prone/pull/3646.
diff --git a/refaster-runner/pom.xml b/refaster-runner/pom.xml
index e23a72e6..54b746dd 100644
--- a/refaster-runner/pom.xml
+++ b/refaster-runner/pom.xml
@@ -56,6 +56,11 @@
             <artifactId>guava</artifactId>
             <scope>provided</scope>
         </dependency>
+        <dependency>
+            <groupId>javax.inject</groupId>
+            <artifactId>javax.inject</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.assertj</groupId>
             <artifactId>assertj-core</artifactId>
diff --git a/refaster-runner/src/main/java/tech/picnic/errorprone/refaster/runner/Refaster.java b/refaster-runner/src/main/java/tech/picnic/errorprone/refaster/runner/Refaster.java
index 49730602..f2a5d8c3 100644
--- a/refaster-runner/src/main/java/tech/picnic/errorprone/refaster/runner/Refaster.java
+++ b/refaster-runner/src/main/java/tech/picnic/errorprone/refaster/runner/Refaster.java
@@ -10,6 +10,7 @@ import static com.google.errorprone.BugPattern.StandardTags.SIMPLIFICATION;
 import static java.util.function.Predicate.not;
 
 import com.google.auto.service.AutoService;
+import com.google.common.annotations.VisibleForTesting;
 import com.google.common.collect.ImmutableCollection;
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableListMultimap;
@@ -40,6 +41,7 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.regex.Pattern;
 import java.util.stream.Stream;
+import javax.inject.Inject;
 
 /**
  * A {@link BugChecker} that flags code that can be simplified using Refaster rules located on the
@@ -75,6 +77,8 @@ public final class Refaster extends BugChecker implements CompilationUnitTreeMat
    *
    * @param flags Any provided command line flags.
    */
+  @Inject
+  @VisibleForTesting
   public Refaster(ErrorProneFlags flags) {
     codeTransformer = createCompositeCodeTransformer(flags);
   }
@@ -165,15 +169,15 @@ public final class Refaster extends BugChecker implements CompilationUnitTreeMat
    * that could cause {@link VisitorState#reportMatch(Description)}} to override the reported
    * severity).
    */
-  @SuppressWarnings("RestrictedApiChecker" /* We create a heavily customized `Description` here. */)
+  @SuppressWarnings("RestrictedApi" /* We create a heavily customized `Description` here. */)
   private static Description augmentDescription(
       Description description, Optional<SeverityLevel> severityOverride) {
     return Description.builder(
             description.position,
             "Refaster Rule",
             description.getLink(),
-            severityOverride.orElse(description.severity),
             String.join(": ", description.checkName, description.getRawMessage()))
+        .overrideSeverity(severityOverride.orElse(description.severity()))
         .addAllFixes(description.fixes)
         .build();
   }
diff --git a/refaster-support/src/main/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformer.java b/refaster-support/src/main/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformer.java
index 6f865b1b..bd3cb5ef 100644
--- a/refaster-support/src/main/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformer.java
+++ b/refaster-support/src/main/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformer.java
@@ -78,7 +78,7 @@ public abstract class AnnotatedCompositeCodeTransformer implements CodeTransform
     }
   }
 
-  @SuppressWarnings("RestrictedApiChecker" /* We create a heavily customized `Description` here. */)
+  @SuppressWarnings("RestrictedApi" /* We create a heavily customized `Description` here. */)
   private Description augmentDescription(
       Description description, CodeTransformer delegate, Context context) {
     String shortCheckName = getShortCheckName(description.checkName);
@@ -86,8 +86,8 @@ public abstract class AnnotatedCompositeCodeTransformer implements CodeTransform
             description.position,
             shortCheckName,
             getLinkPattern(delegate, shortCheckName).orElse(null),
-            overrideSeverity(getSeverity(delegate), context),
             getDescription(delegate))
+        .overrideSeverity(overrideSeverity(getSeverity(delegate), context))
         .addAllFixes(description.fixes)
         .build();
   }
diff --git a/refaster-support/src/test/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformerTest.java b/refaster-support/src/test/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformerTest.java
index 47f30b78..f83353f6 100644
--- a/refaster-support/src/test/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformerTest.java
+++ b/refaster-support/src/test/java/tech/picnic/errorprone/refaster/AnnotatedCompositeCodeTransformerTest.java
@@ -171,10 +171,11 @@ final class AnnotatedCompositeCodeTransformerTest {
     return description(name, Optional.of(""), WARNING, "");
   }
 
-  @SuppressWarnings("RestrictedApiChecker" /* We create a heavily customized `Description` here. */)
+  @SuppressWarnings("RestrictedApi" /* We create a heavily customized `Description` here. */)
   private static Description description(
       String name, Optional<String> link, SeverityLevel severityLevel, String message) {
-    return Description.builder(DUMMY_POSITION, name, link.orElse(null), severityLevel, message)
+    return Description.builder(DUMMY_POSITION, name, link.orElse(null), message)
+        .overrideSeverity(severityLevel)
         .addFix(DUMMY_FIX)
         .build();
   }
diff --git a/refaster-test-support/pom.xml b/refaster-test-support/pom.xml
index 4ef38ddf..54977cfd 100644
--- a/refaster-test-support/pom.xml
+++ b/refaster-test-support/pom.xml
@@ -49,6 +49,11 @@
             <groupId>com.google.guava</groupId>
             <artifactId>guava</artifactId>
         </dependency>
+        <dependency>
+            <groupId>javax.inject</groupId>
+            <artifactId>javax.inject</artifactId>
+            <scope>provided</scope>
+        </dependency>
         <dependency>
             <groupId>org.jspecify</groupId>
             <artifactId>jspecify</artifactId>
diff --git a/refaster-test-support/src/main/java/tech/picnic/errorprone/refaster/test/RefasterRuleCollection.java b/refaster-test-support/src/main/java/tech/picnic/errorprone/refaster/test/RefasterRuleCollection.java
index 8fd5803b..4d68be37 100644
--- a/refaster-test-support/src/main/java/tech/picnic/errorprone/refaster/test/RefasterRuleCollection.java
+++ b/refaster-test-support/src/main/java/tech/picnic/errorprone/refaster/test/RefasterRuleCollection.java
@@ -44,6 +44,7 @@ import java.util.Map;
 import java.util.Optional;
 import java.util.Set;
 import java.util.regex.Pattern;
+import javax.inject.Inject;
 import org.jspecify.annotations.Nullable;
 import tech.picnic.errorprone.refaster.runner.CodeTransformers;
 import tech.picnic.errorprone.refaster.runner.Refaster;
@@ -77,7 +78,8 @@ public final class RefasterRuleCollection extends BugChecker implements Compilat
    *
    * @param flags Any provided command line flags.
    */
-  public RefasterRuleCollection(ErrorProneFlags flags) {
+  @Inject
+  RefasterRuleCollection(ErrorProneFlags flags) {
     ruleCollectionUnderTest = getRuleCollectionUnderTest(flags);
     delegate = createRefasterChecker(ruleCollectionUnderTest);
     rulesUnderTest = getRulesUnderTest(ruleCollectionUnderTest);