re PR c++/46831 ([C++0x] Crash when it tries to do an invalid ICS with a…

re PR c++/46831 ([C++0x] Crash when it tries to do an invalid ICS with a conversion function template)

	PR c++/46831
	* call.c (convert_class_to_reference): Don't try to set up a
	second conv sequence for non-viable candidates.

From-SVN: r170354

gcc/cp/ChangeLog

 2011-02-20  Jason Merrill  <jason@redhat.com>
 
+	PR c++/46831
+	* call.c (convert_class_to_reference): Don't try to set up a
+	second conv sequence for non-viable candidates.
+
 	PR c++/47703
 	* error.c (location_of): Handle non-tagged types.
 

gcc/cp/call.c

@@ -1230,8 +1230,10 @@ convert_class_to_reference (tree reference_type, tree s, tree expr, int flags)
 	     rvalue of the right type is good enough.  */
 	  tree f = cand->fn;
 	  tree t2 = TREE_TYPE (TREE_TYPE (f));
-	  if (TREE_CODE (t2) != REFERENCE_TYPE
-	      || !reference_compatible_p (t, TREE_TYPE (t2)))
+	  if (cand->viable == 0)
+	    /* Don't bother looking more closely.  */;
+	  else if (TREE_CODE (t2) != REFERENCE_TYPE
+		   || !reference_compatible_p (t, TREE_TYPE (t2)))
 	    {
 	      /* No need to set cand->reason here; this is most likely
 		 an ambiguous match.  If it's not, either this candidate

gcc/testsuite/ChangeLog

 2011-02-20  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/cpp0x/fntmpdefarg2.C: New.
+
 	* g++.dg/overload/conv-op1.C: New.
 
 	* g++.dg/cpp0x/constexpr-synth1.C: New.

gcc/testsuite/g++.dg/cpp0x/fntmpdefarg2.C

+// PR c++/46831
+// { dg-options -std=c++0x }
+
+struct B { };
+struct D : B { };
+struct A {
+  template<typename T = void> operator D&();
+  operator long();
+};
+
+void f(long);
+void f(B&);
+
+int main() { f(A()); }