:kind fails with certain QuantifiedConstraints since 8.8
Description and Steps to reproduce
:set -XQuantifiedConstraints -XExplicitForAll -XConstraintKinds -XUndecidableInstances -XAllowAmbiguousTypes -XNoStarIsType -- This works: () :: forall a b . (a => b ~ b) => () -- This fails -- Illegal type synonym family application ‘GHC.Types.Any @Type’ in instance: -- (b :: GHC.Types.Any @Type) ~ (b :: GHC.Types.Any @Type) :kind forall a b . (a => b ~ b) => () -- Slight changes make it work, these are all okay: :kind forall a b . (a => b ~ b) => b :kind forall a b . (a => b ~ a) => () :kind forall a b . (b => b ~ b) => ()
This works in 8.6.5.
-XNoStarIsType is here is because otherwise the error message confusingly contains
@*, which wouldn't be parsed as visible kind application (correctly it would have to be
:kind forall a b . (a => b ~ b) => () to return
Type, as it does in 8.6.5.
- GHC version used: