From 05121d84b33c1fd765d6998d01ef530592590ea6 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Wed, 8 Aug 2018 12:05:29 +0200
Subject: [PATCH] fixes a long standing nil bug in substr

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

diff --git a/lib/system/sysstr.nim b/lib/system/sysstr.nim
index 19c2c62ad..77f2ca040 100644
--- a/lib/system/sysstr.nim
+++ b/lib/system/sysstr.nim
@@ -95,6 +95,7 @@ proc mnewString(len: int): NimString {.compilerProc.} =
 
 proc copyStrLast(s: NimString, start, last: int): NimString {.compilerProc.} =
   let start = max(start, 0)
+  if s == nil: return nil
   let len = min(last, s.len-1) - start + 1
   if len > 0:
     result = rawNewStringNoInit(len)