From da2c1be49c8407856a705278d2261e9734f8ea6c Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Tue, 14 Sep 2021 21:11:37 -0500
Subject: [PATCH] Fix #801 threaded abstract cyclic references in marshalling.

We forgot to mark threaded abstract types as "seen" when marshalling so
we would mistakenly marshal them twice. This messed up unmarshalling.
---
 src/core/marsh.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/core/marsh.c b/src/core/marsh.c
index b732ac6f..54bbe978 100644
--- a/src/core/marsh.c
+++ b/src/core/marsh.c
@@ -384,6 +384,7 @@ static void marshal_one_abstract(MarshalState *st, Janet x, int flags) {
         janet_abstract_incref(abstract);
         pushbyte(st, LB_THREADED_ABSTRACT);
         pushbytes(st, (uint8_t *) &abstract, sizeof(abstract));
+        MARK_SEEN();
         return;
     }
 #endif