From 53b55cb7b1f9836daa5ab4c7e31fa784fdfa4c4b Mon Sep 17 00:00:00 2001
From: Spencer Janssen <sjanssen@cse.unl.edu>
Date: Tue, 24 Jul 2007 16:59:27 +0200
Subject: Remove redundant 'n >= 0' check from shift.  (from David Roundy's
 'simplify shift, removing unneeded check.' patch)

darcs-hash:20070724145927-a5988-2e681f183964587aedd9d0b1e0ab33f7e25779ba
---
 StackSet.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'StackSet.hs')

diff --git a/StackSet.hs b/StackSet.hs
index 265359c..29b2a48 100644
--- a/StackSet.hs
+++ b/StackSet.hs
@@ -487,7 +487,7 @@ swapMaster = modify' $ \c -> case c of
 -- element on the current stack, the original stackSet is returned.
 --
 shift :: (Ord a, Eq s, Integral i) => i -> StackSet i a s sd -> StackSet i a s sd
-shift n s = if n >= 0 && n `tagMember` s && n /= curtag
+shift n s = if n `tagMember` s && n /= curtag
               then maybe s go (peek s) else s
     where go w = view curtag . insertUp w . view n . delete w $ s
           curtag = tag (workspace (current s))
-- 
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