re PR c++/41468 (SFINAE for expressions doesn't consider ambiguous conversion sequences)

	PR c++/41468
	* call.c (convert_like_real) [ck_ambig]: Just return error_mark_node
	if we don't want errors.

From-SVN: r158799

gcc/cp/ChangeLog

 2010-04-27  Jason Merrill  <jason@redhat.com>
 
 	PR c++/41468
+	* call.c (convert_like_real) [ck_ambig]: Just return error_mark_node
+	if we don't want errors.
+
+	PR c++/41468
 	* class.c (convert_to_base): Add complain parameter.  Pass
 	ba_quiet to lookup_base if we don't want errors.
 	(build_vfield_ref): Pass complain to convert_to_base.

gcc/cp/call.c

@@ -4947,6 +4947,8 @@ convert_like_real (conversion *convs, tree expr, tree fn, int argnum,
         }
       return expr;
     case ck_ambig:
+      if (!(complain & tf_error))
+	return error_mark_node;
       /* Call build_user_type_conversion again for the error.  */
       return build_user_type_conversion
 	(totype, convs->u.expr, LOOKUP_NORMAL);

gcc/testsuite/ChangeLog

@@ -2,6 +2,7 @@
 
 	PR c++/41468
 	* g++.dg/template/sfinae17.C: New.
+	* g++.dg/template/sfinae18.C: New.
 
 2010-04-27  Fabien Chêne  <fabien.chene@gmail.com>
 

gcc/testsuite/g++.dg/template/sfinae18.C

+// PR c++/41468
+
+typedef int Ft(int);
+struct A { operator Ft*(); };
+struct B { operator Ft*(); };
+struct C : A, B { };
+
+template<typename C> void f(int (*a)[sizeof(C()(0))]);
+template<typename C> void f(...);
+int main() { f<C>(0); }