From 3a5dfd6a0390f71eb620f73fe08018f4ca5af96a Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Sat, 8 Oct 2016 10:25:55 +0200
Subject: [PATCH] fixes #4845

---
 compiler/semexprs.nim | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/compiler/semexprs.nim b/compiler/semexprs.nim
index 93d5ed1a2b..fbbaaf483b 100644
--- a/compiler/semexprs.nim
+++ b/compiler/semexprs.nim
@@ -136,8 +136,10 @@ proc isCastable(dst, src: PType): bool =
   #                       tyProc, tySet, tyEnum, tyBool, tyChar}
   if skipTypes(dst, abstractInst-{tyOpenArray}).kind == tyOpenArray:
     return false
-  var dstSize, srcSize: BiggestInt
+  if skipTypes(src, abstractInst-{tyTypeDesc}).kind == tyTypeDesc:
+    return false
 
+  var dstSize, srcSize: BiggestInt
   dstSize = computeSize(dst)
   srcSize = computeSize(src)
   if dstSize < 0: