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GHC confused about type synonym kind with QuantifiedConstraints

{-# LANGUAGE KindSignatures, RankNTypes, ConstraintKinds, QuantifiedConstraints #-}
module Bug where
import Data.Constraint

type E (c :: * -> Constraint) = forall (a :: *). Eq a => c a
Bug.hs:5:58: error:
    • Expected a type, but ‘c a’ has kind ‘Constraint’
    • In the type ‘forall (a :: *). Eq a => c a’
      In the type declaration for ‘E’
  |
5 | type E (c :: * -> Constraint) = forall (a :: *). Eq a => c a
  |                                                          ^^^

Note that GHC accepts the program when the Eq a constraint is removed.

Trac metadata
Trac field Value
Version 8.6.3
Type Bug
TypeOfFailure OtherFailure
Priority normal
Resolution Unresolved
Component Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture
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