PR c++/81429 - wrong parsing of constructor with C++11 attribute.

	* parser.c (cp_parser_constructor_declarator_p): Handle the scenario
	when a parameter declaration begins with [[attribute]].

	* g++.dg/cpp0x/gen-attrs-68.C: New test.
	* g++.dg/cpp0x/gen-attrs-69.C: New test.

From-SVN: r274181

gcc/cp/ChangeLog

 2019-08-07  Marek Polacek  <polacek@redhat.com>
 
+	PR c++/81429 - wrong parsing of constructor with C++11 attribute.
+	* parser.c (cp_parser_constructor_declarator_p): Handle the scenario
+	when a parameter declaration begins with [[attribute]].
+
+2019-08-07  Marek Polacek  <polacek@redhat.com>
+
 	PR c++/91346 - Implement P1668R1, allow unevaluated asm in constexpr.
 	* constexpr.c (cxx_eval_constant_expression): Handle ASM_EXPR.
 	(potential_constant_expression_1) <case ASM_EXPR>: Allow.

gcc/cp/parser.c

@@ -27857,7 +27857,9 @@ cp_parser_constructor_declarator_p (cp_parser *parser, cp_parser_flags flags,
 	  /* A parameter declaration begins with a decl-specifier,
 	     which is either the "attribute" keyword, a storage class
 	     specifier, or (usually) a type-specifier.  */
-	  && !cp_lexer_next_token_is_decl_specifier_keyword (parser->lexer))
+	  && !cp_lexer_next_token_is_decl_specifier_keyword (parser->lexer)
+	  /* A parameter declaration can also begin with [[attribute]].  */
+	  && !cp_next_tokens_can_be_std_attribute_p (parser))
 	{
 	  tree type;
 	  tree pushed_scope = NULL_TREE;

gcc/testsuite/ChangeLog

 2019-08-07  Marek Polacek  <polacek@redhat.com>
 
+	PR c++/81429 - wrong parsing of constructor with C++11 attribute.
+	* g++.dg/cpp0x/gen-attrs-68.C: New test.
+	* g++.dg/cpp0x/gen-attrs-69.C: New test.
+
+2019-08-07  Marek Polacek  <polacek@redhat.com>
+
 	PR c++/91346 - Implement P1668R1, allow unevaluated asm in constexpr.
 	* g++.dg/cpp2a/inline-asm1.C: New test.
 	* g++.dg/cpp2a/inline-asm2.C: New test.

gcc/testsuite/g++.dg/cpp0x/gen-attrs-68.C

+// PR c++/81429 - wrong parsing of constructor with C++11 attribute.
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wunused-parameter -Wno-pedantic" }
+
+void fn1([[maybe_unused]] int a) { }
+void fn2(int a [[maybe_unused]]) { }
+void fn3(__attribute__((unused)) int a) { }
+void fn4(int a __attribute__((unused))) { }
+
+struct S1 {
+  S1([[maybe_unused]] int a) { }
+};
+
+struct S2 {
+  S2([[maybe_unused]] int f, [[maybe_unused]] int a) { }
+};
+
+struct S3 {
+  S3(int a [[maybe_unused]]) { }
+};
+
+struct S4 {
+  S4(int f [[maybe_unused]], int a [[maybe_unused]]) { }
+};
+
+struct S5 {
+  S5(__attribute__((unused)) int a) { }
+};
+
+struct S6 {
+  S6(__attribute__((unused)) int f, __attribute__((unused)) int a) { }
+};
+
+struct S7 {
+  S7(int a __attribute__((unused))) { }
+};
+
+struct S8 {
+  S8(int f __attribute__((unused)), int a __attribute__((unused))) { }
+};

gcc/testsuite/g++.dg/cpp0x/gen-attrs-69.C

+// PR c++/81429 - wrong parsing of constructor with C++11 attribute.
+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-Wno-pedantic" }
+
+void fn1([[maybe_unused]] int);
+void fn2(int a [[maybe_unused]]);
+void fn3(__attribute__((unused)) int);
+void fn4(int __attribute__((unused)));
+
+struct S1 {
+  S1([[maybe_unused]] int);
+};
+
+struct S2 {
+  S2([[maybe_unused]] int, [[maybe_unused]] int);
+};
+
+struct S3 {
+  S3(int a [[maybe_unused]]);
+};
+
+struct S4 {
+  S4(int a [[maybe_unused]], int b [[maybe_unused]]);
+};
+
+struct S5 {
+  S5(__attribute__((unused)) int);
+};
+
+struct S6 {
+  S6(__attribute__((unused)) int, __attribute__((unused)) int);
+};
+
+struct S7 {
+  S7(int __attribute__((unused)));
+};
+
+struct S8 {
+  S8(int __attribute__((unused)), int __attribute__((unused)));
+};