diff -r 5c0024338cef -r 168b928d5024 src/HOL/Tools/Function/function_lib.ML
--- a/src/HOL/Tools/Function/function_lib.ML	Wed Nov 11 09:02:37 2009 +0100
+++ b/src/HOL/Tools/Function/function_lib.ML	Wed Nov 11 10:06:30 2009 +0100
@@ -30,8 +30,8 @@
     | (Const ("Pair", Type ("fun", [Ta, Type ("fun", [Tb, _])]))) $ us $ vs =>  
       (HOLogic.split_const (Ta,Tb, fastype_of t)) $ (tupled_lambda us (tupled_lambda vs t))
     | _ => raise Match
-                 
-                 
+
+
 fun dest_all (Const ("all", _) $ Abs (a as (_,T,_))) =
     let
       val (n, body) = Term.dest_abs a
@@ -39,7 +39,7 @@
       (Free (n, T), body)
     end
   | dest_all _ = raise Match
-                         
+
 
 (* Removes all quantifiers from a term, replacing bound variables by frees. *)
 fun dest_all_all (t as (Const ("all",_) $ _)) = 
@@ -50,7 +50,7 @@
       (v :: vs, b')
     end
   | dest_all_all t = ([],t)
-                     
+
 
 (* FIXME: similar to Variable.focus *)
 fun dest_all_all_ctx ctx (Const ("all", _) $ Abs (a as (n,T,b))) =
@@ -161,9 +161,9 @@
    Goal.prove_internal []
      (cterm_of thy
        (Logic.mk_equals (t,
-          if is = []
+          if null is
           then mk (Const (neu, ty), foldr1 mk (map (nth xs) js))
-          else if js = []
+          else if null js
             then mk (foldr1 mk (map (nth xs) is), Const (neu, ty))
             else mk (foldr1 mk (map (nth xs) is), foldr1 mk (map (nth xs) js)))))
      (K (rewrite_goals_tac ac