[clang] [Clang] Fixed auto parsing regression with brace initialization (PR #210347)

[Tony Guillot via cfe-commits]

https://github.com/to268 created https://github.com/llvm/llvm-project/pull/210347

The PR #208552 has introduced a regression where brace initialization was not taken into account `auto foo{12}`. It was also breaking `dcl.type.general` p2 rules, which is also now tested.

>From 36078caa68f388f9cc2cf1db21909a90866049fd Mon Sep 17 00:00:00 2001
From: Tony Guillot <tony.guillot at protonmail.com>
Date: Fri, 17 Jul 2026 16:14:32 +0200
Subject: [PATCH] Fixed auto parsing regression

---
 clang/lib/Parse/ParseDecl.cpp                       |  8 ++++----
 .../dcl/dcl.spec/dcl.type/dcl.type.general/p2.cpp   | 13 +++++++++++++
 2 files changed, 17 insertions(+), 4 deletions(-)
 create mode 100644 clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.type.general/p2.cpp

diff --git a/clang/lib/Parse/ParseDecl.cpp b/clang/lib/Parse/ParseDecl.cpp
index 88f07bb104fcb..0825678acaf60 100644
--- a/clang/lib/Parse/ParseDecl.cpp
+++ b/clang/lib/Parse/ParseDecl.cpp
@@ -3879,10 +3879,10 @@ void Parser::ParseDeclarationSpecifiers(
       // when a variable name matches a type brought in by a using-directive.
       if (DS.getTypeSpecType() == DeclSpec::TST_auto) {
         Token Next = NextToken();
-        if (Next.isOneOf(tok::equal, tok::l_paren, tok::l_square, tok::amp,
-                         tok::ampamp, tok::star, tok::coloncolon, tok::comma,
-                         tok::semi, tok::colon, tok::greater, tok::r_paren,
-                         tok::arrow))
+        if (Next.isOneOf(tok::equal, tok::l_paren, tok::l_square, tok::l_brace,
+                         tok::amp, tok::ampamp, tok::star, tok::coloncolon,
+                         tok::comma, tok::semi, tok::colon, tok::greater,
+                         tok::r_paren, tok::arrow))
           goto DoneWithDeclSpec;
       }
 
diff --git a/clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.type.general/p2.cpp b/clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.type.general/p2.cpp
new file mode 100644
index 0000000000000..5b0079a1ba898
--- /dev/null
+++ b/clang/test/CXX/dcl/dcl.spec/dcl.type/dcl.type.general/p2.cpp
@@ -0,0 +1,13 @@
+// RUN:  %clang_cc1 -std=c++2c -verify %s
+
+namespace bug {
+void func1() {
+  typedef float foo; // expected-note {{previous definition is here}}
+  auto foo{16};      // expected-error {{redefinition of 'foo' as different kind of symbol}}
+}
+
+typedef float bar;
+void func2() {
+  auto bar{16};
+}
+} // namespace bug