From b00129b5c18be6b2ffba3519761d90bc7ad0764c Mon Sep 17 00:00:00 2001
From: Zubin Duggal <zubin@cmi.ac.in>
Date: Mon, 22 Mar 2021 16:14:32 +0530
Subject: [PATCH] plug leak in bind

---
 src/Text/Parsec/Prim.hs | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/Text/Parsec/Prim.hs b/src/Text/Parsec/Prim.hs
index 1dfd7bd..9da4b48 100644
--- a/src/Text/Parsec/Prim.hs
+++ b/src/Text/Parsec/Prim.hs
@@ -318,7 +318,9 @@ parserBind m k
   = ParsecT $ \s cok cerr eok eerr ->
     let
         -- consumed-okay case for m
-        mcok x s err =
+        mcok x s err
+          | errorIsUnknown err = unParser (k x) s cok cerr cok cerr
+          | otherwise =
             let
                  -- if (k x) consumes, those go straigt up
                  pcok = cok
@@ -335,7 +337,9 @@ parserBind m k
             in  unParser (k x) s pcok pcerr peok peerr
 
         -- empty-ok case for m
-        meok x s err =
+        meok x s err
+          | errorIsUnknown err = unParser (k x) s cok cerr eok eerr
+          | otherwise =
             let
                 -- in these cases, (k x) can return as empty
                 pcok = cok