[clang] [clang-format] Correctly annotate kw_operator in using decls (PR #136545)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/136545

Fix #136541

>From a0c0686da2d708f2365c4edcf72c8be5dbc0c4a1 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Mon, 21 Apr 2025 01:26:22 -0700
Subject: [PATCH] [clang-format] Correctly annotate kw_operator in using decls

Fix #136541
---
 clang/lib/Format/TokenAnnotator.cpp           | 6 ++++--
 clang/unittests/Format/TokenAnnotatorTest.cpp | 5 +++++
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 144983f675828..4827549cf9cec 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -3977,8 +3977,10 @@ void TokenAnnotator::calculateFormattingInformation(AnnotatedLine &Line) const {
   FormatToken *AfterLastAttribute = nullptr;
   FormatToken *ClosingParen = nullptr;
 
-  for (auto *Tok = FirstNonComment ? FirstNonComment->Next : nullptr; Tok;
-       Tok = Tok->Next) {
+  for (auto *Tok = FirstNonComment && FirstNonComment->isNot(tok::kw_using)
+                       ? FirstNonComment->Next
+                       : nullptr;
+       Tok; Tok = Tok->Next) {
     if (Tok->is(TT_StartOfName))
       SeenName = true;
     if (Tok->Previous->EndsCppAttributeGroup)
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 043ee2e088ddb..64acc00be125f 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -1078,6 +1078,11 @@ TEST_F(TokenAnnotatorTest, UnderstandsOverloadedOperators) {
   ASSERT_EQ(Tokens.size(), 11u) << Tokens;
   EXPECT_TOKEN(Tokens[3], tok::identifier, TT_FunctionDeclarationName);
   EXPECT_TOKEN(Tokens[7], tok::l_paren, TT_OverloadedOperatorLParen);
+
+  Tokens = annotate("using std::operator==;");
+  ASSERT_EQ(Tokens.size(), 7u) << Tokens;
+  // Not TT_FunctionDeclarationName.
+  EXPECT_TOKEN(Tokens[3], tok::kw_operator, TT_Unknown);
 }
 
 TEST_F(TokenAnnotatorTest, OverloadedOperatorInTemplate) {