From aa2dfd1cefa55221715155c33d25474a5bed346c Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Tue, 19 Feb 2019 19:37:16 +0100
Subject: [PATCH] fixes a critical strutils bug [backport]

(cherry picked from commit 68ce92d4eb6143b8c49001f4782b74eb98027c77)
---
 lib/pure/strutils.nim | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/pure/strutils.nim b/lib/pure/strutils.nim
index cc55301752..e373baa46d 100644
--- a/lib/pure/strutils.nim
+++ b/lib/pure/strutils.nim
@@ -435,7 +435,7 @@ proc isNilOrWhitespace*(s: string): bool {.noSideEffect, procvar, rtl, extern: "
 proc substrEq(s: string, pos: int, substr: string): bool =
   var i = 0
   var length = substr.len
-  while i < length and s[pos+i] == substr[i]:
+  while i < length and pos+i < s.len and s[pos+i] == substr[i]:
     inc i
   return i == length