stylish-haskell icon indicating copy to clipboard operation
stylish-haskell copied to clipboard

Parse error with TypeFamilyDependencies

Open loewenstein opened this issue 7 years ago • 0 comments

Given the following module using TypeFamilyDependencies

21:21 $ cat src/Bug.hs
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeFamilyDependencies #-}

module Bug where

type family F a = b | b -> a where
  F A = B

data A = A
data B = B

GHC compiles just fine

✔ /tmp/stylish
21:21 $ stack exec ghc src/Bug.hs
[1 of 1] Compiling Bug              ( src/Bug.hs, src/Bug.o )

but stylish-haskell complains

✔ /tmp/stylish
21:21 $ stack exec stylish-haskell src/Bug.hs
Language.Haskell.Stylish.Parse.parseModule: could not parse src/Bug.hs: ParseFailed (SrcLoc "<unknown>.hs" 6 17) "Parse error: ="
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeFamilyDependencies #-}

module Bug where

type family F a = b | b -> a where
  F A = B

data A = A
data B = B

loewenstein avatar Dec 08 '17 20:12 loewenstein