1.1 --- a/src/HOL/Tools/TFL/usyntax.ML	Thu Jun 09 15:38:49 2011 +0200
     1.2 +++ b/src/HOL/Tools/TFL/usyntax.ML	Thu Jun 09 16:34:49 2011 +0200
     1.3 @@ -238,7 +238,7 @@
     1.4  
     1.5  fun dest_abs used (a as Abs(s, ty, M)) =
     1.6       let
     1.7 -       val s' = Name.variant used s;
     1.8 +       val s' = singleton (Name.variant_list used) s;
     1.9         val v = Free(s', ty);
    1.10       in ({Bvar = v, Body = Term.betapply (a,v)}, s'::used)
    1.11       end