From f1bf65f66e8bc3acb0afea4699a48c514189d355 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Fri, 12 Jan 2018 15:08:02 +0100
Subject: [PATCH] gc.nim: Add a gcAssert to enforce the no heap sharing
 restrictions

---
 lib/system/gc.nim | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/system/gc.nim b/lib/system/gc.nim
index dac06119d9..a0c943c350 100644
--- a/lib/system/gc.nim
+++ b/lib/system/gc.nim
@@ -639,6 +639,7 @@ when useMarkForDebug or useBackupGc:
     while gch.tempStack.len > 0:
       dec gch.tempStack.len
       var d = gch.tempStack.d[gch.tempStack.len]
+      gcAssert isAllocatedPtr(gch.region, d), "markS: foreign heap root detected!"
       if not containsOrIncl(gch.marked, d):
         forAllChildren(d, waMarkPrecise)