diff -r 010eefa0a4f3 -r 7a86358a3c0b src/Tools/eqsubst.ML
--- a/src/Tools/eqsubst.ML	Fri Dec 13 23:53:02 2013 +0100
+++ b/src/Tools/eqsubst.ML	Sat Dec 14 17:28:05 2013 +0100
@@ -328,7 +328,7 @@
     val st2 = Thm.rotate_rule (j - 1) i st; (* put premice first *)
     val preelimrule =
       RW_Inst.rw ctxt m rule pth
-      |> (Seq.hd o prune_params_tac)
+      |> (Seq.hd o prune_params_tac ctxt)
       |> Thm.permute_prems 0 ~1 (* put old asm first *)
       |> unfix_frees cfvs (* unfix any global params *)
       |> Conv.fconv_rule Drule.beta_eta_conversion; (* normal form *)