git.iko.soy/servant
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Use CPP to avoid errors with old GHC from TypeApplications in class instance
commita445fbafd6b02eaae589e2e18879070c79131d7b authorTeo Camarasu <teofilcamarasu@gmail.com> dateTue 18 Oct 2022, 11:06 (4 years ago) parent52f76ea
2 files changed+22−4
compare with master
unifiedsplit
servant-server/src/Servant/Server/Internal.hs+11−2 servant/src/Servant/Links.hs+11−2
servant-server/src/Servant/Server/Internal.hs+11−2
@@ -1,5 +1,6 @@
11{-# LANGUAGE AllowAmbiguousTypes #-}
22{-# LANGUAGE ConstraintKinds #-}
3+{-# LANGUAGE CPP #-}
34{-# LANGUAGE DataKinds #-}
45{-# LANGUAGE DeriveDataTypeable #-}
56{-# LANGUAGE FlexibleContexts #-}
@@ -823,7 +824,11 @@ instance (HasContextEntry context (NamedContext name subContext), HasServer subA
823824-------------------------------------------------------------------------------
824825
825826-- Erroring instance for 'HasServer' when a combinator is not fully applied
826−instance TypeError (PartialApplication @(Type -> [Type] -> Constraint) HasServer arr) => HasServer ((arr :: a -> b) :> sub) context
827+instance TypeError (PartialApplication
828+#if __GLASGOW_HASKELL__ >= 904
829+ @(Type -> [Type] -> Constraint)
830+#endif
831+ HasServer arr) => HasServer ((arr :: a -> b) :> sub) context
827832 where
828833 type ServerT (arr :> sub) _ = TypeError (PartialApplication (HasServer :: * -> [*] -> Constraint) arr)
829834 route = error "unreachable"
@@ -867,7 +872,11 @@ type HasServerArrowTypeError a b =
867872-- XXX: This omits the @context@ parameter, e.g.:
868873--
869874-- "There is no instance for HasServer (Bool :> …)". Do we care ?
870−instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub @(Type -> [Type] -> Constraint) HasServer ty) => HasServer (ty :> sub) context
875+instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub
876+#if __GLASGOW_HASKELL__ >= 904
877+ @(Type -> [Type] -> Constraint)
878+#endif
879+ HasServer ty) => HasServer (ty :> sub) context
871880
872881instance {-# OVERLAPPABLE #-} TypeError (NoInstanceFor (HasServer api context)) => HasServer api context
873882
servant/src/Servant/Links.hs+11−2
@@ -1,5 +1,6 @@
11{-# LANGUAGE AllowAmbiguousTypes #-}
22{-# LANGUAGE ConstraintKinds #-}
3+{-# LANGUAGE CPP #-}
34{-# LANGUAGE DataKinds #-}
45{-# LANGUAGE FlexibleContexts #-}
56{-# LANGUAGE FlexibleInstances #-}
@@ -649,12 +650,20 @@ simpleToLink _ toA _ = toLink toA (Proxy :: Proxy sub)
649650-- >>> import Data.Text (Text)
650651
651652-- Erroring instance for 'HasLink' when a combinator is not fully applied
652−instance TypeError (PartialApplication @(Type -> Constraint) HasLink arr) => HasLink ((arr :: a -> b) :> sub)
653+instance TypeError (PartialApplication
654+#if __GLASGOW_HASKELL__ >= 904
655+ @(Type -> Constraint)
656+#endif
657+ HasLink arr) => HasLink ((arr :: a -> b) :> sub)
653658 where
654659 type MkLink (arr :> sub) _ = TypeError (PartialApplication (HasLink :: * -> Constraint) arr)
655660 toLink = error "unreachable"
656661
657662-- Erroring instances for 'HasLink' for unknown API combinators
658−instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub @(Type -> Constraint) HasLink ty) => HasLink (ty :> sub)
663+instance {-# OVERLAPPABLE #-} TypeError (NoInstanceForSub
664+#if __GLASGOW_HASKELL__ >= 904
665+ @(Type -> Constraint)
666+#endif
667+ HasLink ty) => HasLink (ty :> sub)
659668
660669instance {-# OVERLAPPABLE #-} TypeError (NoInstanceFor (HasLink api)) => HasLink api