diff -r bb64d089c643 -r 3acab6c90d4a src/HOL/Tools/Nitpick/nitpick_preproc.ML
--- a/src/HOL/Tools/Nitpick/nitpick_preproc.ML	Wed Feb 17 12:14:21 2010 +0100
+++ b/src/HOL/Tools/Nitpick/nitpick_preproc.ML	Wed Feb 17 13:38:02 2010 +0100
@@ -517,8 +517,7 @@
         | (Const (x as (s, T)), args) =>
           let val arg_Ts = binder_types T in
             if length arg_Ts = length args andalso
-               (is_constr thy x orelse s = @{const_name Pair} orelse
-                x = (@{const_name Suc}, nat_T --> nat_T)) andalso
+               (is_constr thy x orelse s = @{const_name Pair}) andalso
                (not careful orelse not (is_Var t1) orelse
                 String.isPrefix val_var_prefix (fst (fst (dest_Var t1)))) then
               discriminate_value hol_ctxt x t1 ::