diff options
| author | mniip <mniip@mniip.com> | 2018-11-01 18:33:10 -0400 |
|---|---|---|
| committer | Ben Gamari <ben@smart-cactus.org> | 2018-11-01 20:32:23 -0400 |
| commit | f877d9cc99dd1ba0c038e70527031e9ba0934cd3 (patch) | |
| tree | 6a225a9cfafc670ca0fb16cd4402efcc059788b6 /compiler/utils | |
| parent | 1c92f193ee406545daedd06e0b9d5d7354d9af64 (diff) | |
| download | haskell-f877d9cc99dd1ba0c038e70527031e9ba0934cd3.tar.gz | |
Move eta-reduced coaxiom compatibility handling quirks into FamInstEnv.
The quirk caused an issue where GHC concluded that 'D' is possibly
unifiable with 'D a' (the two types could have the same kind if D is a
data family).
Test Plan:
Ensure T9371 stays fixed.
Introduce T15704
Reviewers: goldfire, bgamari
Reviewed By: goldfire
Subscribers: RyanGlScott, rwbarton, carter
GHC Trac Issues: #15704
Differential Revision: https://phabricator.haskell.org/D5206
Diffstat (limited to 'compiler/utils')
| -rw-r--r-- | compiler/utils/Util.hs | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/compiler/utils/Util.hs b/compiler/utils/Util.hs index c348f79888..c6c5362112 100644 --- a/compiler/utils/Util.hs +++ b/compiler/utils/Util.hs @@ -16,7 +16,7 @@ module Util ( -- * General list processing zipEqual, zipWithEqual, zipWith3Equal, zipWith4Equal, - zipLazy, stretchZipWith, zipWithAndUnzip, + zipLazy, stretchZipWith, zipWithAndUnzip, zipAndUnzip, zipWithLazy, zipWith3Lazy, @@ -441,6 +441,15 @@ zipWithAndUnzip f (a:as) (b:bs) (r1:rs1, r2:rs2) zipWithAndUnzip _ _ _ = ([],[]) +-- | This has the effect of making the two lists have equal length by dropping +-- the tail of the longer one. +zipAndUnzip :: [a] -> [b] -> ([a],[b]) +zipAndUnzip (a:as) (b:bs) + = let (rs1, rs2) = zipAndUnzip as bs + in + (a:rs1, b:rs2) +zipAndUnzip _ _ = ([],[]) + mapAccumL2 :: (s1 -> s2 -> a -> (s1, s2, b)) -> s1 -> s2 -> [a] -> (s1, s2, [b]) mapAccumL2 f s1 s2 xs = (s1', s2', ys) where ((s1', s2'), ys) = mapAccumL (\(s1, s2) x -> case f s1 s2 x of |