adamgundry

{-# LANGUAGE DataKinds, PolyKinds, StandaloneKindSignatures, TypeFamilies, UndecidableInstances #-}

    import GHC.TypeLits
    import Data.Kind

    -- This is the proposed API for Warning/WarningBin

    type Warning :: Symbol -> WarningBin -> ErrorMessage -> Constraint
    class Warning flag bin msg

adamgundry

{-# LANGUAGE DataKinds #-}
{-# LANGUAGE OverloadedLabels #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UndecidableInstances #-}

import qualified Data.ByteString.Char8 as BS
import Data.Kind
import Data.Proxy
import GHC.OverloadedLabels

adamgundry

{-# LANGUAGE GHC2021, NoScopedTypeVariables, RequiredTypeArguments, AllowAmbiguousTypes  #-}

import Data.Proxy

hasScopedTypeVariables :: Bool
hasScopedTypeVariables = f Char

f :: forall a -> C a => Bool
f a = g @Int
  where