c++: Allow GNU attributes before lambda -> [PR90333]

In my 9.3/10 patch for 90333 I allowed attributes between [] and (), and
after the trailing return type, but not in the place that GCC 8 expected
them, and we've gotten several bug reports about that.  So let's allow them
there, as well.

gcc/cp/ChangeLog:

	PR c++/90333
	* parser.c (cp_parser_lambda_declarator_opt): Accept GNU attributes
	between () and ->.

gcc/testsuite/ChangeLog:

	PR c++/90333
	* g++.dg/ext/attr-lambda3.C: New test.

2 files changed, 13 insertions, 2 deletions

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index c52f90c..bb1499a 100644
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -11391,7 +11391,12 @@ cp_parser_lambda_declarator_opt (cp_parser* parser, tree lambda_expr)
       omitted_parms_loc = UNKNOWN_LOCATION;
     }
 
-  std_attrs = cp_parser_std_attribute_spec_seq (parser);
+  /* GCC 8 accepted attributes here, and this is the place for standard C++11
+     attributes that appertain to the function type.  */
+  if (cp_next_tokens_can_be_gnu_attribute_p (parser))
+    gnu_attrs = cp_parser_gnu_attributes_opt (parser);
+  else
+    std_attrs = cp_parser_std_attribute_spec_seq (parser);
 
   /* Parse optional trailing return type.  */
   if (cp_lexer_next_token_is (parser->lexer, CPP_DEREF))
@@ -11405,8 +11410,10 @@ cp_parser_lambda_declarator_opt (cp_parser* parser, tree lambda_expr)
       return_type = cp_parser_trailing_type_id (parser);
     }
 
+  /* Also allow GNU attributes at the very end of the declaration, the usual
+     place for GNU attributes.  */
   if (cp_next_tokens_can_be_gnu_attribute_p (parser))
-    gnu_attrs = cp_parser_gnu_attributes_opt (parser);
+    gnu_attrs = chainon (gnu_attrs, cp_parser_gnu_attributes_opt (parser));
 
   if (has_param_list)
     {
diff --git a/gcc/testsuite/g++.dg/ext/attr-lambda3.C b/gcc/testsuite/g++.dg/ext/attr-lambda3.C
new file mode 100644
index 0000000..f9c3ec1
--- /dev/null
+++ b/gcc/testsuite/g++.dg/ext/attr-lambda3.C
@@ -0,0 +1,4 @@
+// PR c++/90333
+// { dg-do compile { target c++11 } }
+
+auto x = []() __attribute__((always_inline)) -> int { return 0; }