From 48537fec814e556dcb12183c31061c4645d7b743 Mon Sep 17 00:00:00 2001
From: Araq <rumpf_a@web.de>
Date: Wed, 18 Sep 2019 12:01:05 +0200
Subject: [PATCH] fixes #12209

---
 lib/pure/os.nim | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/pure/os.nim b/lib/pure/os.nim
index 65b98d7a1..e59c0962d 100644
--- a/lib/pure/os.nim
+++ b/lib/pure/os.nim
@@ -1740,8 +1740,8 @@ template walkCommon(pattern: string, filter) =
           # that the file extensions have the same length ...
           let ff = getFilename(f)
           let idx = ff.len - pattern.len + dotPos
-          if dotPos < 0 or idx >= ff.len or ff[idx] == '.' or
-              pattern[dotPos+1] == '*':
+          if dotPos < 0 or idx >= ff.len or (idx >= 0 and ff[idx] == '.') or
+              (dotPos >= 0 and dotPos+1 < pattern.len and pattern[dotPos+1] == '*'):
             yield splitFile(pattern).dir / extractFilename(ff)
         if findNextFile(res, f) == 0'i32:
           let errCode = getLastError()