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authorRyan Scott <ryan.gl.scott@gmail.com>2017-06-02 13:12:11 -0400
committerBen Gamari <ben@smart-cactus.org>2017-06-02 13:12:13 -0400
commita786b136f48dfcf907dad55bcdbc4fcd247f2794 (patch)
tree9c6abee43aa398fdd8168b1cb7bd2d3fb5e6bacf /compiler/rename/RnPat.hs
parent811a2986475d88f73bb22b4600970039e1b582d6 (diff)
downloadhaskell-a786b136f48dfcf907dad55bcdbc4fcd247f2794.tar.gz
Use lengthIs and friends in more places
While investigating #12545, I discovered several places in the code that performed length-checks like so: ``` length ts == 4 ``` This is not ideal, since the length of `ts` could be much longer than 4, and we'd be doing way more work than necessary! There are already a slew of helper functions in `Util` such as `lengthIs` that are designed to do this efficiently, so I found every place where they ought to be used and did just that. I also defined a couple more utility functions for list length that were common patterns (e.g., `ltLength`). Test Plan: ./validate Reviewers: austin, hvr, goldfire, bgamari, simonmar Reviewed By: bgamari, simonmar Subscribers: goldfire, rwbarton, thomie Differential Revision: https://phabricator.haskell.org/D3622
Diffstat (limited to 'compiler/rename/RnPat.hs')
-rw-r--r--compiler/rename/RnPat.hs2
1 files changed, 1 insertions, 1 deletions
diff --git a/compiler/rename/RnPat.hs b/compiler/rename/RnPat.hs
index 7c4663c080..30dd61bece 100644
--- a/compiler/rename/RnPat.hs
+++ b/compiler/rename/RnPat.hs
@@ -625,7 +625,7 @@ rnHsRecFields ctxt mk_arg (HsRecFields { rec_flds = flds, rec_dotdot = dotdot })
rn_dotdot (Just {}) Nothing _flds -- Constructor out of scope
= return []
rn_dotdot (Just n) (Just con) flds -- ".." on record construction / pat match
- = ASSERT( n == length flds )
+ = ASSERT( flds `lengthIs` n )
do { loc <- getSrcSpanM -- Rather approximate
; dd_flag <- xoptM LangExt.RecordWildCards
; checkErr dd_flag (needFlagDotDot ctxt)