eeva/servant
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

feat: Polymorphic Elem for Union (#1637)

Browse source 
Close https://github.com/haskell-servant/servant/issues/1590
This commit is contained in:
Guillaume Bouchard 2022-12-23 09:42:52 +01:00 committed by GitHub
parent 6392dce4bf
commit a4194dc490
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
1 changed files with 2 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
servant/src/Servant/API/UVerb/Union.hs
View file

@ -128,9 +128,9 @@ type DuplicateElementError (rs :: [k]) =
':$$: 'Text " " ':<>: 'ShowType rs
type family Elem (x :: k) (xs :: [k]) :: Bool where
Elem x (x ': _) = 'True
Elem x (_ ': xs) = Elem x xs
Elem _ '[] = 'False
Elem x (x' ': xs) =
If (x == x') 'True (Elem x xs)
type family Unique xs :: Constraint where
Unique xs = If (Nubbed xs == 'True) (() :: Constraint) (TypeError (DuplicateElementError xs))