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Fix GHC 9.2 build 

Close #1513.

GHC 9.2 needs explicit kind signature here, I don't really understand
why.

This kind signature is correct and not too restritive, because `HasLink`
is technically defined `class HasLink endpoint` which means that it is
infered as `k -> Constraint`. In the instance signature, we have
`HasLink ((arr :: a -> b) :> sub)`, so here the `k` is the same kind as
the one of `:>` which is not polykinded.
This commit is contained in:
Guillaume Bouchard 2022-01-24 17:10:33 +01:00
parent 75db4a5327
commit 22d5790e73
1 changed files with 1 additions and 1 deletions
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servant/src/Servant/Links.hs
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@ -649,7 +649,7 @@ simpleToLink _ toA _ = toLink toA (Proxy :: Proxy sub)
-- Erroring instance for 'HasLink' when a combinator is not fully applied
instance TypeError (PartialApplication HasLink arr) => HasLink ((arr :: a -> b) :> sub)
where
type MkLink (arr :> sub) _ = TypeError (PartialApplication HasLink arr)
type MkLink (arr :> sub) _ = TypeError (PartialApplication (HasLink :: * -> Constraint) arr)
toLink = error "unreachable"
-- Erroring instances for 'HasLink' for unknown API combinators