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spl / dlist

Difference lists in Haskell
https://hackage.haskell.org/package/dlist
BSD 3-Clause "New" or "Revised" License
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GHC 9.4: warning about missing `LANGUAGE TypeOperators` #106

Closed andreasabel closed 1 year ago

andreasabel commented 2 years ago

This warning can be fixed in a backwards-compatible way by adding TypeOperators to default-extensions: in the .cabal file.

Building library for dlist-1.0..
[1 of 5] Compiling Data.DList.Internal ( Data/DList/Internal.hs, dist/build/Data/DList/Internal.o, dist/build/Data/DList/Internal.dyn_o )

Data/DList/Internal.hs:642:12: warning: [-Wtype-equality-requires-operators]
    The use of ‘~’ without TypeOperators
    will become an error in a future GHC release.
    Suggested fix: Perhaps you intended to use TypeOperators
    |
642 | instance a ~ Char => IsString (DList a) where
    |            ^
[2 of 5] Compiling Data.DList       ( Data/DList.hs, dist/build/Data/DList.o, dist/build/Data/DList.dyn_o )
[3 of 5] Compiling Data.DList.DNonEmpty.Internal ( Data/DList/DNonEmpty/Internal.hs, dist/build/Data/DList/DNonEmpty/Internal.o, dist/build/Data/DList/DNonEmpty/Internal.dyn_o )

Data/DList/DNonEmpty/Internal.hs:459:12: warning: [-Wtype-equality-requires-operators]
    The use of ‘~’ without TypeOperators
    will become an error in a future GHC release.
    Suggested fix: Perhaps you intended to use TypeOperators
    |
459 | instance a ~ Char => IsString (DNonEmpty a) where
    |            ^