src/Pure/Syntax/parser.ML

--- a/src/Pure/Syntax/parser.ML	Wed Aug 12 21:38:39 2015 +0200
+++ b/src/Pure/Syntax/parser.ML	Thu Aug 13 11:05:19 2015 +0200
@@ -429,7 +429,7 @@
             map prod_of_chain (these (AList.lookup (op =) chains tag));
       in map (pretty_prod name) nt_prods end;
 
-  in maps pretty_nt (sort_wrt fst (Symtab.dest tags)) end;
+  in maps pretty_nt (sort_by fst (Symtab.dest tags)) end;