[gcc r13-5462] c: Disallow braces around C2x auto initializers

[Joseph Myers <jsm28@gcc.gnu.org>]

https://gcc.gnu.org/g:84eb39556cc8449e04b5f48bd5c131941a7a2529

commit r13-5462-g84eb39556cc8449e04b5f48bd5c131941a7a2529
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Fri Jan 27 21:38:57 2023 +0000

    c: Disallow braces around C2x auto initializers
    
    WG14 agreed at this week's meeting to remove support for braces around
    auto scalar initializers, as incompatible with C++ auto handling of
    braced initializers; thus remove that support in GCC.
    
    Bootstrapped with no regressions for x86_64-pc-linux-gnu.
    
    gcc/c/
            * c-parser.cc (c_parser_declaration_or_fndef): Do not allow braces
            around auto initializer.
    
    gcc/testsuite/
            * gcc.dg/c2x-auto-1.c, gcc.dg/c2x-auto-3.c: Expect braces around
            auto initializers to be disallowed.

Diff:
---
 gcc/c/c-parser.cc                 | 13 +------------
 gcc/testsuite/gcc.dg/c2x-auto-1.c |  4 ++--
 gcc/testsuite/gcc.dg/c2x-auto-3.c |  7 +++++++
 3 files changed, 10 insertions(+), 14 deletions(-)

diff --git a/gcc/c/c-parser.cc b/gcc/c/c-parser.cc
index 803b04b8dc1..69230002bc8 100644
--- a/gcc/c/c-parser.cc
+++ b/gcc/c/c-parser.cc
@@ -2480,18 +2480,7 @@ c_parser_declaration_or_fndef (c_parser *parser, bool fndef_ok,
 		  int flag_sanitize_save = flag_sanitize;
 		  if (nested && !empty_ok)
 		    flag_sanitize = 0;
-		  if (std_auto_type_p
-		      && c_parser_next_token_is (parser, CPP_OPEN_BRACE))
-		    {
-		      matching_braces braces;
-		      braces.consume_open (parser);
-		      init = c_parser_expr_no_commas (parser, NULL);
-		      if (c_parser_next_token_is (parser, CPP_COMMA))
-			c_parser_consume_token (parser);
-		      braces.skip_until_found_close (parser);
-		    }
-		  else
-		    init = c_parser_expr_no_commas (parser, NULL);
+		  init = c_parser_expr_no_commas (parser, NULL);
 		  if (std_auto_type_p)
 		    finish_underspecified_init (underspec_name,
 						underspec_state);
diff --git a/gcc/testsuite/gcc.dg/c2x-auto-1.c b/gcc/testsuite/gcc.dg/c2x-auto-1.c
index f8460fb3bfb..c50daccfe89 100644
--- a/gcc/testsuite/gcc.dg/c2x-auto-1.c
+++ b/gcc/testsuite/gcc.dg/c2x-auto-1.c
@@ -4,14 +4,14 @@
 
 auto i = 1;
 extern int i;
-static auto l = { 0L };
+static auto l = 0L;
 extern long l;
 extern auto const d = 0.0; /* { dg-warning "initialized and declared 'extern'" } */
 extern const double d;
 double dx;
 auto ((i2)) = 3;
 extern int i2;
-const auto i3 [[]] = { 4, };
+const auto i3 [[]] = 4;
 extern int i4;
 thread_local auto f = 1.0f;
 float ff;
diff --git a/gcc/testsuite/gcc.dg/c2x-auto-3.c b/gcc/testsuite/gcc.dg/c2x-auto-3.c
index a34ce31f6be..1ab3cc74d35 100644
--- a/gcc/testsuite/gcc.dg/c2x-auto-3.c
+++ b/gcc/testsuite/gcc.dg/c2x-auto-3.c
@@ -62,3 +62,10 @@ f5 ()
 {
   static int auto e10 = 3; /* { dg-error "multiple storage classes in declaration specifiers" } */
 }
+
+void
+f6 ()
+{
+  static auto l = { 0L }; /* { dg-error "expected expression" } */
+  const auto i3 [[]] = { 4, }; /* { dg-error "expected expression" } */
+}