[clang] [clang-format] Handle C-style cast of qualified type (PR #108929)

[Owen Pan via cfe-commits]

https://github.com/owenca created https://github.com/llvm/llvm-project/pull/108929

Fixes #102874.

>From db3da97b684403fdbf38b0f029438c00cfa16a5f Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Mon, 16 Sep 2024 21:31:29 -0700
Subject: [PATCH] [clang-format] Handle C-style cast of qualified type

Fixes #102874.
---
 clang/lib/Format/TokenAnnotator.cpp           | 13 ++++++++-----
 clang/unittests/Format/TokenAnnotatorTest.cpp |  8 ++++++++
 2 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/clang/lib/Format/TokenAnnotator.cpp b/clang/lib/Format/TokenAnnotator.cpp
index dfa703aed0d34d..eabb6e68d75b09 100644
--- a/clang/lib/Format/TokenAnnotator.cpp
+++ b/clang/lib/Format/TokenAnnotator.cpp
@@ -2840,11 +2840,14 @@ class AnnotatingParser {
     if (AfterRParen->isOneOf(tok::identifier, tok::kw_this))
       return true;
 
-    // Look for a cast `( x ) (`.
-    if (AfterRParen->is(tok::l_paren) && BeforeRParen->Previous) {
-      if (BeforeRParen->is(tok::identifier) &&
-          BeforeRParen->Previous->is(tok::l_paren)) {
-        return true;
+    // Look for a cast `( x ) (`, where x may be a qualified identifier.
+    if (AfterRParen->is(tok::l_paren)) {
+      for (const auto *Prev = BeforeRParen; Prev->is(tok::identifier);) {
+        Prev = Prev->Previous;
+        if (Prev->is(tok::coloncolon))
+          Prev = Prev->Previous;
+        if (Prev == LParen)
+          return true;
       }
     }
 
diff --git a/clang/unittests/Format/TokenAnnotatorTest.cpp b/clang/unittests/Format/TokenAnnotatorTest.cpp
index 5c28e3a4ea5a1f..f97b47be772e62 100644
--- a/clang/unittests/Format/TokenAnnotatorTest.cpp
+++ b/clang/unittests/Format/TokenAnnotatorTest.cpp
@@ -781,6 +781,14 @@ TEST_F(TokenAnnotatorTest, UnderstandsCasts) {
   EXPECT_TOKEN(Tokens[9], tok::r_paren, TT_Unknown);
   EXPECT_TOKEN(Tokens[10], tok::minus, TT_BinaryOperator);
 
+  Tokens = annotate("return (::Type)(1 + 2);");
+  ASSERT_EQ(Tokens.size(), 12u) << Tokens;
+  EXPECT_TOKEN(Tokens[4], tok::r_paren, TT_CastRParen);
+
+  Tokens = annotate("return (Namespace::Class)(1 + 2);");
+  ASSERT_EQ(Tokens.size(), 13u) << Tokens;
+  EXPECT_TOKEN(Tokens[5], tok::r_paren, TT_CastRParen);
+
   auto Style = getLLVMStyle();
   Style.TypeNames.push_back("Foo");
   Tokens = annotate("#define FOO(bar) foo((Foo)&bar)", Style);