re PR c++/57327 ('derived' is an ambiguous base class of 'base' diagnostic is backwards)

/cp
2013-05-20  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/57327
	* pt.c (unify_no_common_base): Swap arg and parm arguments to inform.

/testsuite
2013-05-20  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/57327
	* g++.dg/template/error50.C: New.

From-SVN: r199097

gcc/cp/ChangeLog

 2013-05-20  Paolo Carlini  <paolo.carlini@oracle.com>
 
+	PR c++/57327
+	* pt.c (unify_no_common_base): Swap arg and parm arguments to inform.
+
+2013-05-20  Paolo Carlini  <paolo.carlini@oracle.com>
+
 	PR c++/10207
 	* parser.c (cp_parser_postfix_expression): Use cp_parser_braced_list
 	instead of cp_parser_initializer_list for compound-literals.

gcc/cp/pt.c

@@ -5375,7 +5375,7 @@ unify_no_common_base (bool explain_p, enum template_base_result r,
       {
       case tbr_ambiguous_baseclass:
 	inform (input_location, "  %qT is an ambiguous base class of %qT",
-		arg, parm);
+		parm, arg);
 	break;
       default:
 	inform (input_location, "  %qT is not derived from %qT", arg, parm);

gcc/testsuite/ChangeLog

 2013-05-20  Paolo Carlini  <paolo.carlini@oracle.com>
 
+	PR c++/57327
+	* g++.dg/template/error50.C: New.
+
+2013-05-20  Paolo Carlini  <paolo.carlini@oracle.com>
+
 	PR c++/10207
 	* g++.dg/ext/complit13.C: New.
 

gcc/testsuite/g++.dg/template/error50.C

+// PR c++/57327
+
+template<class T>
+struct A {};
+
+template<class T>
+void f(A<T>&) {}
+
+struct B : A<long> {};
+
+struct C : A<char> {};
+
+struct D : B, C {};
+
+int main()
+{
+  D d;
+  f(d);  // { dg-error "no matching" }
+}        // { dg-message "'A<T>' is an ambiguous base" "" { target *-*-* } 18 }