-Wtype-equality-requires-operators warning building Cabal-syntax with ghc-9.4 #8268
Closed as not planned
Description
After adding lot of allow-newer building Cabal-syntax with ghc-9.4 throws this warning:
Preprocessing library for Cabal-syntax-3.9.0.0..
Building library for Cabal-syntax-3.9.0.0..
....
src\Distribution\Compat\Graph.hs:180:37: error: [-Wtype-equality-requires-operators, -Werror=type-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
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180 | instance (IsNode a, IsNode b, Key a ~ Key b) => IsNode (Either a b) where
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