PR c++/92739 - parsing requires clause with attributes.

gcc/cp/
	* parser.c (cp_parser_constraint_requires_parens): Exclude
	attributes as postfix expressions.

gcc/testsuite/
	* g++.dg/concepts-pr92739.C: New test.

From-SVN: r279935

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3e5f58cac2a2a97de242ca55fabcc842a8d099cf..02ebb9fbf9421b2c4bbe15c3147d1079b60bb470 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-01-06  Andrew Sutton  <asutton@lock3software.com>
+
+       PR c++/92739 - parsing requires clause with attributes.
+       * parser.c (cp_parser_constraint_requires_parens): Exclude
+       attributes as postfix expressions.
+
 2020-01-05  Jakub Jelinek  <jakub@redhat.com>
 
        PR c++/93138

diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c
index 7cd8e150dd520a2a468a8aeae30d1b75f4f74434..1ea05ddd497c1fd8bd99c27f787acf16584aed49 100644 (file)
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -27256,6 +27256,14 @@ cp_parser_constraint_requires_parens (cp_parser *parser, bool lambda_p)
          gcc_fallthrough ();
        }
       case CPP_OPEN_SQUARE:
+       {
+         /* A primary-constraint-expression followed by a '[[' is not a
+            postfix expression.  */
+         if (cp_lexer_nth_token_is (parser->lexer, 2, CPP_OPEN_SQUARE))
+           return pce_ok;
+
+         gcc_fallthrough ();
+       }
       case CPP_PLUS_PLUS:
       case CPP_MINUS_MINUS:
       case CPP_DOT:

diff --git a/gcc/testsuite/g++.dg/cpp2a/concepts-attrib1.C b/gcc/testsuite/g++.dg/cpp2a/concepts-attrib1.C
new file mode 100644 (file)
index 0000000..0154afa
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/concepts-attrib1.C
@@ -0,0 +1,15 @@
+// PR c++/92739
+// { dg-do compile { target concepts } }
+
+template <class T>
+concept C = true;
+
+template <class T>
+  requires C<T>
+[[nodiscard]] int f(T t) {
+  return 22;
+}
+
+int main() {
+  return 0;
+}