From b58dd1e4f9ba3225bd9423feac717d6c581272c3 Mon Sep 17 00:00:00 2001
From: Gijs de Jong <berichtaangijs@gmail.com>
Date: Thu, 10 Aug 2023 09:28:36 -0700
Subject: [PATCH] Prevent `SuggestedFixes#renameMethod` from modifying return
 type declaration

By ensuring the return type `IDENTIFIER` token is not matched.

Fixes #4043

COPYBARA_INTEGRATE_REVIEW=https://github.com/google/error-prone/pull/4043 from PicnicSupermarket:gdejong/bug-method-name cbfbc5401eb659a7aef08317250fc20425cf09e7
PiperOrigin-RevId: 555523619
---
 .../errorprone/fixes/SuggestedFixes.java      |  5 ++--
 .../bugpatterns/MemberNameTest.java           | 28 +++++++++++++++++++
 2 files changed, 31 insertions(+), 2 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 6b2e28d3562..f448941037b 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
@@ -745,11 +745,12 @@ public Void visitMemberSelect(MemberSelectTree tree, Void unused) {
 
   /** Be warned, only changes method name at the declaration. */
   public static SuggestedFix renameMethod(MethodTree tree, String replacement, VisitorState state) {
-    // Search tokens from beginning of method tree to beginning of method body.
-    int basePos = getStartPosition(tree);
+    // Search tokens from end of return type tree to beginning of method body.
+    int basePos = state.getEndPosition(tree.getReturnType());
     int endPos =
         tree.getBody() != null ? getStartPosition(tree.getBody()) : state.getEndPosition(tree);
     List<ErrorProneToken> methodTokens = state.getOffsetTokens(basePos, endPos);
+
     for (ErrorProneToken token : methodTokens) {
       if (token.kind() == TokenKind.IDENTIFIER && token.name().equals(tree.getName())) {
         return SuggestedFix.replace(token.pos(), token.endPos(), replacement);
diff --git a/core/src/test/java/com/google/errorprone/bugpatterns/MemberNameTest.java b/core/src/test/java/com/google/errorprone/bugpatterns/MemberNameTest.java
index 6e58cfdb57a..a1da16d7349 100644
--- a/core/src/test/java/com/google/errorprone/bugpatterns/MemberNameTest.java
+++ b/core/src/test/java/com/google/errorprone/bugpatterns/MemberNameTest.java
@@ -463,4 +463,32 @@ public void methodReference() {
             "}")
         .doTest();
   }
+
+  @Test
+  public void methodNameWithMatchingReturnType() {
+    refactoringHelper
+        .addInputLines(
+            "Test.java",
+            "class Test {",
+            "  private Object Object() {",
+            "    return null;",
+            "  }",
+            "",
+            "  void call() {",
+            "     Object();",
+            "  }",
+            "}")
+        .addOutputLines(
+            "Test.java",
+            "class Test {",
+            "  private Object object() {",
+            "    return null;",
+            "  }",
+            "",
+            "  void call() {",
+            "     object();",
+            "  }",
+            "}")
+        .doTest();
+  }
 }