src/Pure/thm.ML

     val newBi = Logic.list_rename_params (newnames, Bi);
   in
     (case duplicates (op =) cs of
       a :: _ => (warning ("Can't rename.  Bound variables not distinct: " ^ a); state)
     | [] =>
-      (case inter (op =) (cs, freenames) of
+      (case inter (op =) cs freenames of
         a :: _ => (warning ("Can't rename.  Bound/Free variable clash: " ^ a); state)
       | [] =>
         Thm (der,
          {thy_ref = thy_ref,
           tags = tags,