diff -r 7d97f60293ae -r 04e21a27c0ad src/Pure/Syntax/parser.ML
--- a/src/Pure/Syntax/parser.ML	Thu Sep 08 16:08:50 2005 +0200
+++ b/src/Pure/Syntax/parser.ML	Thu Sep 08 16:09:23 2005 +0200
@@ -724,7 +724,7 @@
         (_, _, _, Nonterminal (nt, minPrec) :: _, _, _) =>
           let                                       (*predictor operation*)
             val (used', new_states) =
-              (case assoc (used, nt) of
+              (case AList.lookup (op =) used nt of
                 SOME (usedPrec, l) =>       (*nonterminal has been processed*)
                   if usedPrec <= minPrec then
                                       (*wanted precedence has been processed*)