re PR c++/84644 (internal compiler error: in warn_misplaced_attr_for_class_type, at cp/decl.c:4718)

/cp
2018-12-15  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/84644
	* decl.c (check_tag_decl): A decltype with no declarator
	doesn't declare anything.

/testsuite
2018-12-15  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/84644
	* g++.dg/cpp0x/decltype68.C: New.
	* g++.dg/cpp0x/decltype-33838.C: Adjust.
	* g++.dg/template/spec32.C: Likewise.
	* g++.dg/template/ttp22.C: Likewise.

From-SVN: r267165

gcc/cp/ChangeLog

+2018-12-15  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/84644
+	* decl.c (check_tag_decl): A decltype with no declarator
+	doesn't declare anything.
+
 2018-12-14  Alexandre Oliva <aoliva@redhat.com>
 
 	PR c++/87814

gcc/cp/decl.c

@@ -4803,15 +4803,20 @@ check_tag_decl (cp_decl_specifier_seq *declspecs,
     declared_type = declspecs->type;
   else if (declspecs->type == error_mark_node)
     error_p = true;
-  if (declared_type == NULL_TREE && ! saw_friend && !error_p)
-    permerror (input_location, "declaration does not declare anything");
-  else if (declared_type != NULL_TREE && type_uses_auto (declared_type))
+
+  if (type_uses_auto (declared_type))
     {
       error_at (declspecs->locations[ds_type_spec],
 		"%<auto%> can only be specified for variables "
 		"or function declarations");
       return error_mark_node;
     }
+
+  if (declared_type && !OVERLOAD_TYPE_P (declared_type))
+    declared_type = NULL_TREE;
+
+  if (!declared_type && !saw_friend && !error_p)
+    permerror (input_location, "declaration does not declare anything");
   /* Check for an anonymous union.  */
   else if (declared_type && RECORD_OR_UNION_CODE_P (TREE_CODE (declared_type))
 	   && TYPE_UNNAMED_P (declared_type))

gcc/testsuite/ChangeLog

+2018-12-15  Paolo Carlini  <paolo.carlini@oracle.com>
+
+	PR c++/84644
+	* g++.dg/cpp0x/decltype68.C: New.
+	* g++.dg/cpp0x/decltype-33838.C: Adjust.
+	* g++.dg/template/spec32.C: Likewise.
+	* g++.dg/template/ttp22.C: Likewise.
+
 2018-12-15  Jakub Jelinek  <jakub@redhat.com>
 
 	PR target/88489

gcc/testsuite/g++.dg/cpp0x/decltype-33838.C

@@ -2,5 +2,5 @@
 // PR c++/33838
 template<typename T> struct A
 {
-  __decltype (T* foo()); // { dg-error "expected|no arguments|accept" }
+  __decltype (T* foo()); // { dg-error "expected|no arguments|declaration" }
 };

gcc/testsuite/g++.dg/cpp0x/decltype68.C

+// PR c++/84644
+// { dg-do compile { target c++11 } }
+
+template<int a>
+struct b {
+  decltype(a) __attribute__((break));  // { dg-error "declaration does not declare anything" }
+};

gcc/testsuite/g++.dg/template/spec32.C

@@ -2,5 +2,5 @@
 
 struct A
 {
-  template<template<int> class B> struct B<0>;  // { dg-error "name of class shadows" }
+  template<template<int> class B> struct B<0>;  // { dg-error "declaration does not declare anything" }
 };

gcc/testsuite/g++.dg/template/ttp22.C

@@ -2,7 +2,7 @@
 // { dg-do compile }
 
 template<template<int> class A>
-class A<0>;  // { dg-error "shadows template template parameter" }
+class A<0>;  // { dg-error "declaration does not declare anything" }
 
 template<template<int> class B>
 class B<0> {};  // { dg-error "shadows template template parameter" }