diff --git a/src/version.ml b/src/version.ml
index 89f523077..c5ff7de01 100644
--- a/src/version.ml
+++ b/src/version.ml
@@ -1 +1 @@
-let version = "Version 1.00, cc9f3d0ed, Tue Aug 25 23:21:39 2020 +0300"
+let version = "Version 1.00, f81a63865, Wed Aug 26 00:27:42 2020 +0300"
diff --git a/stdlib/Ostap.lama b/stdlib/Ostap.lama
index 71fb2b551..96bf087ef 100644
--- a/stdlib/Ostap.lama
+++ b/stdlib/Ostap.lama
@@ -43,12 +43,12 @@ public fun memo (f) {
       if log then printf ("Applying memoized parser to %s\n", s.string) fi;
       case findMap (deref (t), s) of
         None  ->
-          t ::= addMap (deref (t), s, [addSet (emptySet (compare), k), emptySet (compare)]);
+          t ::= addMap (deref (t), s, [addSet (emptySet (compare), k), emptySet (fun (r1, r2) {case [r1, r2] of [Fail (_, _, _), Fail (_, _, _)] -> 0 | _ -> compare (r1, r2) esac      })]);
           f (fun (r) {
                r := lookupMemo (restab, r);
                if log then printf ("Running continuation with result %s\n", r.string) fi;
                case findMap (deref (t), s) of
-                 Some ([ks, rs]) ->
+                 Some ([ks, rs]) ->                   
                    if memSet (rs, r)
                    then skip
                    else