diff -r b0cd55afead1 -r d4a35f82fbb4 src/Pure/General/stack.ML
--- a/src/Pure/General/stack.ML	Tue Oct 04 16:47:40 2005 +0200
+++ b/src/Pure/General/stack.ML	Tue Oct 04 19:01:37 2005 +0200
@@ -7,7 +7,7 @@
 
 signature STACK =
 sig
-  type 'a T = 'a * 'a list
+  type 'a T (*= 'a * 'a list*)
   val level: 'a T -> int
   val init: 'a -> 'a T
   val top: 'a T -> 'a