[clang] [clang-format] Fix a bug in annotating CastRParen (PR #107675)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/107675

Fixes #107568.

>From 6deac871ceae8ba3918570a4bdbd8476e014a3a1 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Sat, 7 Sep 2024 01:39:34 -0700
Subject: [PATCH] [clang-format] Fix a bug in annotating CastRParen

Fixes #107568.
---
 clang/lib/Format/TokenAnnotator.cpp           | 29 +++++++++++--------
 clang/unittests/Format/TokenAnnotatorTest.cpp |  6 ++++
 2 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index 6a1cf61659fd97..dfa703aed0d34d 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2874,21 +2874,26 @@ class AnnotatingParser {
     if (Line.InPPDirective && AfterRParen->is(tok::minus))
       return false;
 
+    const auto *Prev = BeforeRParen;
+
+    // Look for a function pointer type, e.g. `(*)()`.
+    if (Prev->is(tok::r_paren)) {
+      if (Prev->is(TT_CastRParen))
+        return false;
+      Prev = Prev->MatchingParen;
+      if (!Prev)
+        return false;
+      Prev = Prev->Previous;
+      if (!Prev || Prev->isNot(tok::r_paren))
+        return false;
+      Prev = Prev->MatchingParen;
+      return Prev && Prev->is(TT_FunctionTypeLParen);
+    }
+
     // Search for unexpected tokens.
-    for (auto *Prev = BeforeRParen; Prev != LParen; Prev = Prev->Previous) {
-      if (Prev->is(tok::r_paren)) {
-        if (Prev->is(TT_CastRParen))
-          return false;
-        Prev = Prev->MatchingParen;
-        if (!Prev)
-          return false;
-        if (Prev->is(TT_FunctionTypeLParen))
-          break;
-        continue;
-      }
+    for (Prev = BeforeRParen; Prev != LParen; Prev = Prev->Previous)
       if (!Prev->isOneOf(tok::kw_const, tok::identifier, tok::coloncolon))
         return false;
-    }
 
     return true;
   }
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 1bb796fd6f5ee9..36a6db9283893e 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -775,6 +775,12 @@ TEST_F(TokenAnnotatorTest, UnderstandsCasts) {
   EXPECT_TOKEN(Tokens[8], tok::r_paren, TT_Unknown);
   EXPECT_TOKEN(Tokens[9], tok::minus, TT_BinaryOperator);
 
+  Tokens = annotate("return (double)(foo(30)) - 15;");
+  ASSERT_EQ(Tokens.size(), 14u) << Tokens;
+  EXPECT_TOKEN(Tokens[3], tok::r_paren, TT_CastRParen);
+  EXPECT_TOKEN(Tokens[9], tok::r_paren, TT_Unknown);
+  EXPECT_TOKEN(Tokens[10], tok::minus, TT_BinaryOperator);
+
   auto Style = getLLVMStyle();
   Style.TypeNames.push_back("Foo");
   Tokens = annotate("#define FOO(bar) foo((Foo)&bar)", Style);