Index: cp/parser.c
===================================================================
--- cp/parser.c	(revision 201233)
+++ cp/parser.c	(working copy)
@@ -12261,7 +12261,6 @@ cp_parser_operator (cp_parser* parser)
   tree id = NULL_TREE;
   cp_token *token;
   bool bad_encoding_prefix = false;
-  int string_len = 2;
 
   /* Peek at the next token.  */
   token = cp_lexer_peek_token (parser->lexer);
@@ -12462,20 +12461,22 @@ cp_parser_operator (cp_parser* parser)
       return ansi_opname (ARRAY_REF);
 
     case CPP_WSTRING:
-      string_len = 3;
     case CPP_STRING16:
     case CPP_STRING32:
-      string_len = 5;
     case CPP_UTF8STRING:
-      string_len = 4;
-      bad_encoding_prefix = true;
+     bad_encoding_prefix = true;
+      /* Fall through.  */
+
     case CPP_STRING:
       if (cxx_dialect == cxx98)
 	maybe_warn_cpp0x (CPP0X_USER_DEFINED_LITERALS);
       if (bad_encoding_prefix)
-	error ("invalid encoding prefix in literal operator");
-      if (TREE_STRING_LENGTH (token->u.value) > string_len)
 	{
+	  error ("invalid encoding prefix in literal operator");
+	  return error_mark_node;
+	}
+      if (TREE_STRING_LENGTH (token->u.value) > 2)
+	{
 	  error ("expected empty string after %<operator%> keyword");
 	  return error_mark_node;
 	}
@@ -12505,21 +12506,23 @@ cp_parser_operator (cp_parser* parser)
 	}
 
     case CPP_WSTRING_USERDEF:
-      string_len = 3;
     case CPP_STRING16_USERDEF:
     case CPP_STRING32_USERDEF:
-      string_len = 5;
     case CPP_UTF8STRING_USERDEF:
-      string_len = 4;
       bad_encoding_prefix = true;
+      /* Fall through.  */
+
     case CPP_STRING_USERDEF:
       if (cxx_dialect == cxx98)
 	maybe_warn_cpp0x (CPP0X_USER_DEFINED_LITERALS);
       if (bad_encoding_prefix)
-	error ("invalid encoding prefix in literal operator");
+	{
+	  error ("invalid encoding prefix in literal operator");
+	  return error_mark_node;
+	}
       {
 	tree string_tree = USERDEF_LITERAL_VALUE (token->u.value);
-	if (TREE_STRING_LENGTH (string_tree) > string_len)
+	if (TREE_STRING_LENGTH (string_tree) > 2)
 	  {
 	    error ("expected empty string after %<operator%> keyword");
 	    return error_mark_node;
Index: testsuite/g++.dg/cpp1y/udlit-empty-string-neg.C
===================================================================
--- testsuite/g++.dg/cpp1y/udlit-empty-string-neg.C	(revision 0)
+++ testsuite/g++.dg/cpp1y/udlit-empty-string-neg.C	(working copy)
@@ -0,0 +1,21 @@
+// { dg-options -std=c++1y }
+
+int
+operator "*"_s(unsigned long long) // { dg-error "expected empty string after 'operator'" }
+{ return 0; }
+
+int
+operator L"*"_Ls(unsigned long long) // { dg-error "invalid encoding prefix in literal operator" }
+{ return 0; }
+
+int
+operator u"*"_s16(unsigned long long) // { dg-error "invalid encoding prefix in literal operator" }
+{ return 0; }
+
+int
+operator U"*"_s32(unsigned long long) // { dg-error "invalid encoding prefix in literal operator" }
+{ return 0; }
+
+int
+operator u8"*"_u8s(unsigned long long) // { dg-error "invalid encoding prefix in literal operator" }
+{ return 0; }