From 5ddbfe1367f7196158c92335022761e290151b38 Mon Sep 17 00:00:00 2001
From: Leonard Chan <leonardchan@google.com>
Date: Fri, 24 Oct 2025 13:10:55 -0700
Subject: [PATCH] Revert "Reapply "[clang-format] Annotate ::operator and
 Foo::operator correctly" (#164670)"

This reverts commit 50ca1f407801cd268a1c130b9576dfb51fe7f392.

Reverting because this leads to the bug on ToT described in
https://github.com/llvm/llvm-project/issues/164866. The original fix
addresses an old regression which we'd still like to land eventually.
See the discussion in https://github.com/llvm/llvm-project/pull/164670
for more context.
---
 clang/lib/Format/TokenAnnotator.cpp           | 10 +++++++---
 clang/unittests/Format/TokenAnnotatorTest.cpp |  5 -----
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 1d0dfd0b9c151..a8a9c51952fbd 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -3791,12 +3791,18 @@ static bool isFunctionDeclarationName(const LangOptions &LangOpts,
   if (Current.is(TT_FunctionDeclarationName))
     return true;
 
-  if (Current.isNoneOf(tok::identifier, tok::kw_operator))
+  if (!Current.Tok.getIdentifierInfo())
     return false;
 
   const auto *Prev = Current.getPreviousNonComment();
   assert(Prev);
 
+  if (Prev->is(tok::coloncolon))
+    Prev = Prev->Previous;
+
+  if (!Prev)
+    return false;
+
   const auto &Previous = *Prev;
 
   if (const auto *PrevPrev = Previous.getPreviousNonComment();
@@ -3845,8 +3851,6 @@ static bool isFunctionDeclarationName(const LangOptions &LangOpts,
 
   // Find parentheses of parameter list.
   if (Current.is(tok::kw_operator)) {
-    if (Line.startsWith(tok::kw_friend))
-      return true;
     if (Previous.Tok.getIdentifierInfo() &&
         Previous.isNoneOf(tok::kw_return, tok::kw_co_return)) {
       return true;
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index ca99940890984..f3637383a0a65 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -1129,11 +1129,6 @@ TEST_F(TokenAnnotatorTest, UnderstandsOverloadedOperators) {
   ASSERT_EQ(Tokens.size(), 7u) << Tokens;
   // Not TT_FunctionDeclarationName.
   EXPECT_TOKEN(Tokens[3], tok::kw_operator, TT_Unknown);
-
-  Tokens = annotate("SomeAPI::operator()();");
-  ASSERT_EQ(Tokens.size(), 9u) << Tokens;
-  // Not TT_FunctionDeclarationName.
-  EXPECT_TOKEN(Tokens[2], tok::kw_operator, TT_Unknown);
 }
 
 TEST_F(TokenAnnotatorTest, OverloadedOperatorInTemplate) {