PR c++/84720 - ICE with rvalue ref non-type argument.

	* pt.c (convert_nontype_argument): Handle rvalue references.

From-SVN: r258501

gcc/cp/ChangeLog

 2018-03-13  Jason Merrill  <jason@redhat.com>
 
+	PR c++/84720 - ICE with rvalue ref non-type argument.
+	* pt.c (convert_nontype_argument): Handle rvalue references.
+
 	PR c++/84839 - ICE with decltype of parameter pack.
 	* pt.c (tsubst_pack_expansion): Set cp_unevaluated_operand while
 	instantiating dummy parms.

gcc/cp/pt.c

@@ -6932,11 +6932,18 @@ convert_nontype_argument (tree type, tree expr, tsubst_flags_t complain)
 	  return NULL_TREE;
 	}
 
-      if (!lvalue_p (expr))
+      if (!glvalue_p (expr)
+	  || TYPE_REF_IS_RVALUE (type) != xvalue_p (expr))
 	{
 	  if (complain & tf_error)
-	    error ("%qE is not a valid template argument for type %qT "
-		   "because it is not an lvalue", expr, type);
+	    {
+	      if (TYPE_REF_IS_RVALUE (type))
+		error ("%qE is not a valid template argument for type %qT "
+		       "because it is not an xvalue", expr, type);
+	      else
+		error ("%qE is not a valid template argument for type %qT "
+		       "because it is not an lvalue", expr, type);
+	    }
 	  return NULL_TREE;
 	}
 

gcc/testsuite/g++.dg/cpp0x/rv-targ1.C

+// PR c++/84720
+// { dg-do compile { target c++11 } }
+
+template<int &&>
+struct a {
+  template<typename...>
+  static void b() {
+    b();
+  }
+};