1.1 --- a/src/Pure/type.ML	Wed Aug 19 17:04:21 1998 +0200
     1.2 +++ b/src/Pure/type.ML	Wed Aug 19 17:05:00 1998 +0200
     1.3 @@ -821,7 +821,7 @@
     1.4  (* user parameters *)
     1.5  
     1.6  fun is_param (x, _) = size x > 0 andalso ord x = ord "?";
     1.7 -fun param used (x, S) = TVar (("?" ^ variant used x, 0), S);
     1.8 +fun param used (x, S) = TVar ((variant used ("?" ^ x), 0), S);
     1.9  
    1.10  
    1.11  (* decode_types *)