diff -r 2be1253a20d3 -r 63eaef3207e1 src/Pure/Isar/specification.ML
--- a/src/Pure/Isar/specification.ML	Sat Sep 22 17:45:57 2007 +0200
+++ b/src/Pure/Isar/specification.ML	Sat Sep 22 17:45:58 2007 +0200
@@ -147,7 +147,7 @@
   let
     val ((vars, [(_, [prop])]), _) =
       prep (the_list raw_var) [(("", []), [raw_prop])]
-        (lthy |> ProofContext.set_expand_abbrevs false);
+        (lthy |> ProofContext.set_mode ProofContext.mode_abbrev);
     val ((x, T), rhs) = LocalDefs.abs_def (#2 (LocalDefs.cert_def lthy prop));
     val mx = (case vars of [] => NoSyn | [((y, _), mx)] =>
       if x = y then mx