re PR c++/51186 (declaring main() with auto but without --std=c++11 gives…

re PR c++/51186 (declaring main() with auto but without --std=c++11 gives inconsistent error messages)

	PR c++/51186
	* decl.c (grokdeclarator): Improve C++98 trailing return diagnostic.

From-SVN: r181455

gcc/cp/ChangeLog

 2011-11-17  Jason Merrill  <jason@redhat.com>
 
+	PR c++/51186
+	* decl.c (grokdeclarator): Improve C++98 trailing return diagnostic.
+
 	N3203
 	* class.c (add_implicitly_declared_members): Update move
 	conditions.

gcc/cp/decl.c

@@ -9126,12 +9126,12 @@ grokdeclarator (const cp_declarator *declarator,
 		    if (!declarator->u.function.late_return_type)
 		      {
 			error ("%qs function uses %<auto%> type specifier without"
-			       " late return type", name);
+			       " trailing return type", name);
 			return error_mark_node;
 		      }
 		    else if (!is_auto (type))
 		      {
-			error ("%qs function with late return type has"
+			error ("%qs function with trailing return type has"
 			       " %qT as its type rather than plain %<auto%>",
 			       name, type);
 			return error_mark_node;
@@ -9139,8 +9139,14 @@ grokdeclarator (const cp_declarator *declarator,
 		  }
 		else if (declarator->u.function.late_return_type)
 		  {
-		    error ("%qs function with late return type not declared"
-			   " with %<auto%> type specifier", name);
+		    if (cxx_dialect < cxx0x)
+		      /* Not using maybe_warn_cpp0x because this should
+			 always be an error.  */
+		      error ("trailing return type only available with "
+			     "-std=c++11 or -std=gnu++11");
+		    else
+		      error ("%qs function with trailing return type not "
+			     "declared with %<auto%> type specifier", name);
 		    return error_mark_node;
 		  }
 	      }

gcc/testsuite/ChangeLog

+2011-11-17  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51186
+	* g++.dg/cpp0x/auto27.C: New.
+	* g++.dg/cpp0x/trailing2.C: Adjust messages.
+
 2011-11-17  Andrew MacLeod  <amacleod@redhat.com>
 
 	* gcc.dg/atomic-generic-aux.c (__atomic_compare_exchange): Fail if 

gcc/testsuite/g++.dg/cpp0x/auto27.C

+// PR c++/51186
+
+auto main()->int	       // { dg-error "std=" "" { target c++98 } }
+			       // { dg-error "auto" "" { target c++98 } 3 }
+			       // { dg-error "no type" "" { target c++98 } 3 }
+{ }

gcc/testsuite/g++.dg/cpp0x/trailing2.C

@@ -3,14 +3,14 @@
 // { dg-options "-std=c++0x" }
 
 auto f1 () -> int;
-auto f2 ();		// { dg-error "without late return type" }
-int f3 () -> int;	// { dg-error "late return type" }
-auto *f4 () -> int;	// { dg-error "late return type" }
+auto f2 ();		// { dg-error "without trailing return type" }
+int f3 () -> int;	// { dg-error "trailing return type" }
+auto *f4 () -> int;	// { dg-error "trailing return type" }
 
 struct A
 {
   auto f5 () const -> int;
-  auto f6 ();		// { dg-error "without late return type" }
-  int f7 () -> int;	// { dg-error "late return type" }
-  auto *f8 () -> int;	// { dg-error "late return type" }
+  auto f6 ();		// { dg-error "without trailing return type" }
+  int f7 () -> int;	// { dg-error "trailing return type" }
+  auto *f8 () -> int;	// { dg-error "trailing return type" }
 };