From be9921779231a78f353e815e1edf41b4d9d8b6e0 Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Fri, 20 Sep 2024 16:09:53 -0700
Subject: [PATCH] Extend MissingOverride to require @Override on "an explicitly
 declared accessor method for a record component"

PiperOrigin-RevId: 677005515
---
 .../bugpatterns/MissingOverride.java          | 24 +++++++++++++++++
 .../bugpatterns/MissingOverrideTest.java      | 26 +++++++++++++++++++
 2 files changed, 50 insertions(+)

diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/MissingOverride.java b/core/src/main/java/com/google/errorprone/bugpatterns/MissingOverride.java
index 124573d266b..0977a47762d 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/MissingOverride.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/MissingOverride.java
@@ -16,11 +16,14 @@
 
 package com.google.errorprone.bugpatterns;
 
+import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.matchers.Description.NO_MATCH;
+import static com.google.errorprone.util.ASTHelpers.getEnclosedElements;
 import static com.google.errorprone.util.ASTHelpers.hasAnnotation;
 import static com.google.errorprone.util.ASTHelpers.streamSuperMethods;
 
+import com.google.common.collect.ImmutableSet;
 import com.google.errorprone.BugPattern;
 import com.google.errorprone.BugPattern.StandardTags;
 import com.google.errorprone.ErrorProneFlags;
@@ -30,6 +33,8 @@
 import com.google.errorprone.matchers.Description;
 import com.google.errorprone.util.ASTHelpers;
 import com.sun.source.tree.MethodTree;
+import com.sun.tools.javac.code.Symbol;
+import com.sun.tools.javac.util.Name;
 import javax.inject.Inject;
 import javax.lang.model.element.Modifier;
 
@@ -61,6 +66,25 @@ public Description matchMethod(MethodTree tree, VisitorState state) {
     if (ignoreInterfaceOverrides && sym.enclClass().isInterface()) {
       return NO_MATCH;
     }
+    if (ASTHelpers.isRecord(sym.owner)
+        && sym.getModifiers().contains(Modifier.PUBLIC)
+        && sym.getParameters().isEmpty()) {
+      ImmutableSet<Name> components =
+          getEnclosedElements(sym.owner).stream()
+              .filter(ASTHelpers::isRecord)
+              .map(Symbol::getSimpleName)
+              .collect(toImmutableSet());
+      if (components.contains(sym.getSimpleName())) {
+        return buildDescription(tree)
+            .addFix(SuggestedFix.prefixWith(tree, "@Override "))
+            .setMessage(
+                String.format(
+                    "%s is an explicitly declared accessor method for a record component; expected"
+                        + " @Override",
+                    sym.getSimpleName()))
+            .build();
+      }
+    }
     return streamSuperMethods(sym, state.getTypes())
         .findFirst()
         .filter(unused -> ASTHelpers.getGeneratedBy(state).isEmpty())
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/MissingOverrideTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/MissingOverrideTest.java
index 52887c875f4..2618bddfcb7 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/MissingOverrideTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/MissingOverrideTest.java
@@ -16,6 +16,8 @@
 
 package com.google.errorprone.bugpatterns;
 
+import static com.google.common.truth.TruthJUnit.assume;
+
 import com.google.common.collect.ImmutableList;
 import com.google.errorprone.CompilationTestHelper;
 import org.junit.Test;
@@ -190,4 +192,28 @@ public interface Test extends Super {
             """)
         .doTest();
   }
+
+  @Test
+  public void explicitRecordAccessor() {
+    assume().that(Runtime.version().feature()).isAtLeast(16);
+
+    compilationHelper
+        .addSourceLines(
+            "Baz.java",
+            """
+            public record Baz(int x) {
+              // BUG: Diagnostic contains: x is an explicitly declared accessor method
+              public int x() {
+                return x;
+              }
+              public int x(int y) {
+                return y;
+              }
+              public int y() {
+                return x;
+              }
+            }
+            """)
+        .doTest();
+  }
 }