From 6b13adfaa2899519ee4333ef730476e978186c3e Mon Sep 17 00:00:00 2001
From: Liam Miller-Cushon <cushon@google.com>
Date: Mon, 15 Jun 2026 02:56:29 -0700
Subject: [PATCH] Fix a crash in ReferenceEquality

Use `getEnclosedElements` which handles symbol completion failures gracefully, and fix a bug in `SuggestedFixes.qualifyType` where it crashed if there were ambiguous wildcard imports.

PiperOrigin-RevId: 932339804
---
 .../errorprone/fixes/SuggestedFixes.java      |  3 +++
 .../bugpatterns/ReferenceEquality.java        | 26 +++++++++----------
 .../bugpatterns/ReferenceEqualityTest.java    | 26 +++++++++++++++++++
 3 files changed, 42 insertions(+), 13 deletions(-)

diff --git a/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java b/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java
index d5bba61bb5e..cfa2637744c 100644
--- a/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java
+++ b/check_api/src/main/java/com/google/errorprone/fixes/SuggestedFixes.java
@@ -497,6 +497,9 @@ public static String qualifyType(VisitorState state, SuggestedFix.Builder fix, S
         return components.subList(i, components.size()).stream().collect(joining("."));
       }
       // Type already imported or otherwise visible.
+      if (found.getKind().equals(ElementKind.OTHER)) {
+        continue;
+      }
       if (found.getQualifiedName().contentEquals(qualifiedName)) {
         return components.subList(i, components.size()).stream().collect(joining("."));
       }
diff --git a/core/src/main/java/com/google/errorprone/bugpatterns/ReferenceEquality.java b/core/src/main/java/com/google/errorprone/bugpatterns/ReferenceEquality.java
index fd180563827..fd89f3fa2be 100644
--- a/core/src/main/java/com/google/errorprone/bugpatterns/ReferenceEquality.java
+++ b/core/src/main/java/com/google/errorprone/bugpatterns/ReferenceEquality.java
@@ -16,9 +16,10 @@
 
 package com.google.errorprone.bugpatterns;
 
-import static com.google.common.collect.Iterables.getOnlyElement;
+import static com.google.common.collect.MoreCollectors.onlyElement;
 import static com.google.errorprone.BugPattern.SeverityLevel.WARNING;
 import static com.google.errorprone.VisitorState.memoize;
+import static com.google.errorprone.util.ASTHelpers.getEnclosedElements;
 import static com.google.errorprone.util.ASTHelpers.getUpperBound;
 import static com.google.errorprone.util.ASTHelpers.isSameType;
 import static com.google.errorprone.util.ASTHelpers.isSubtype;
@@ -34,7 +35,6 @@
 import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.LambdaExpressionTree;
 import com.sun.source.tree.MethodTree;
-import com.sun.tools.javac.code.Scope;
 import com.sun.tools.javac.code.Symbol;
 import com.sun.tools.javac.code.Symbol.ClassSymbol;
 import com.sun.tools.javac.code.Symbol.MethodSymbol;
@@ -105,14 +105,16 @@ private static boolean overridesMethodOnType(
       Type overriddenType,
       String overriddenMethodName,
       VisitorState state) {
-    Symbol overriddenMethodSymbol = getOnlyMember(state, overriddenType, overriddenMethodName);
+    Symbol overriddenMethodSymbol = getOnlyMember(overriddenType, overriddenMethodName);
     return methodSymbol.getSimpleName().contentEquals(overriddenMethodName)
         && methodSymbol.overrides(
             overriddenMethodSymbol, classType.tsym, state.getTypes(), /* checkResult= */ false);
   }
 
-  private static Symbol getOnlyMember(VisitorState state, Type type, String name) {
-    return getOnlyElement(type.tsym.members().getSymbolsByName(state.getName(name)));
+  private static Symbol getOnlyMember(Type type, String name) {
+    return getEnclosedElements(type.tsym).stream()
+        .filter(s -> s.getSimpleName().contentEquals(name))
+        .collect(onlyElement());
   }
 
   /**
@@ -184,18 +186,16 @@ private static boolean definitelyUsesReferenceEquality(Type type, VisitorState s
    */
   private static boolean implementsEquals(Type type, VisitorState state) {
     Name equalsName = EQUALS.get(state);
-    Symbol objectEquals = getOnlyMember(state, state.getSymtab().objectType, "equals");
+    Symbol objectEquals = getOnlyMember(state.getSymtab().objectType, "equals");
     for (Type sup : state.getTypes().closure(type)) {
       if (isSameType(sup, state.getSymtab().objectType, state)) {
         continue;
       }
-      Scope scope = sup.tsym.members();
-      if (scope == null) {
-        continue;
-      }
-      for (Symbol sym : scope.getSymbolsByName(equalsName)) {
-        if (sym.overrides(objectEquals, type.tsym, state.getTypes(), /* checkResult= */ false)) {
-          return true;
+      for (Symbol sym : getEnclosedElements(sup.tsym)) {
+        if (sym.getSimpleName().contentEquals(equalsName)) {
+          if (sym.overrides(objectEquals, type.tsym, state.getTypes(), /* checkResult= */ false)) {
+            return true;
+          }
         }
       }
     }
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/ReferenceEqualityTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/ReferenceEqualityTest.java
index 6613e62fd5a..28b7ae74688 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/ReferenceEqualityTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/ReferenceEqualityTest.java
@@ -900,4 +900,30 @@ boolean f(MemorySegment a) {
             """)
         .doTest();
   }
+
+  @Test
+  public void ambiguousImport() {
+    compilationHelper
+        .addSourceLines(
+            "Objects.java",
+            """
+            package test;
+
+            public class Objects {}
+            """)
+        .addSourceLines(
+            "Test.java",
+            """
+            import java.util.*;
+            import test.*;
+
+            class Test {
+              boolean f(String a, String b) {
+                // BUG: Diagnostic contains: java.util.Objects.equals(a, b)
+                return a == b;
+              }
+            }
+            """)
+        .doTest();
+  }
 }