re PR c++/51613 (Ambiguous function template instantiations as template argument are not rejected)

PR c++/51613
	* pt.c (resolve_overloaded_unification): Compare types with
	same_type_p, not decls_match.

From-SVN: r183099

gcc/cp/ChangeLog

@@ -1,3 +1,9 @@
+2012-01-11  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51613
+	* pt.c (resolve_overloaded_unification): Compare types with
+	same_type_p, not decls_match.
+
 2012-01-10  Jason Merrill  <jason@redhat.com>
 
 	PR c++/51614

gcc/cp/pt.c

@@ -15471,7 +15471,7 @@ resolve_overloaded_unification (tree tparms,
 	      elem = tsubst (TREE_TYPE (fn), subargs, tf_none, NULL_TREE);
 	      if (try_one_overload (tparms, targs, tempargs, parm,
 				    elem, strict, sub_strict, addr_p, explain_p)
-		  && (!goodfn || !decls_match (goodfn, elem)))
+		  && (!goodfn || !same_type_p (goodfn, elem)))
 		{
 		  goodfn = elem;
 		  ++good;

gcc/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2012-01-11  Jason Merrill  <jason@redhat.com>
+
+	PR c++/51613
+	* g++.dg/template/explicit-args5.C: New.
+
 2012-01-11  Matthew Gretton-Dann  <matthew.gretton-dann@arm.com>
 
 	* gcc.c-torture/execute/20120110-1.c: New testcase.

gcc/testsuite/g++.dg/template/explicit-args5.C

@@ -0,0 +1,24 @@
+// PR c++/51613
+
+template<typename F, typename T>
+void apply(F f, T t)
+{
+    f(t);
+}
+
+template<typename T>
+void multi(T)
+{
+}
+
+template<typename T>
+void multi(T*)
+{
+}
+
+int main()
+{
+    apply(&multi<int>, 7);	// { dg-error "no match" }
+
+    return 0;
+}