[GHC] #14607: Core Lint error

22 Dec 2017

      #14607: Core Lint error
-------------------------------------+-------------------------------------
           Reporter:  Iceland_jack   |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.2
           Keywords:  TypeInType,    |  Operating System:  Unknown/Multiple
  DeferredTypeErrors                 |
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  #14605 #14584
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 This produces long {{{#!hs
 {-# Language DerivingStrategies #-}
 {-# Language GADTs #-}
 {-# Language GeneralizedNewtypeDeriving #-}
 {-# Language InstanceSigs #-}
 {-# Language KindSignatures #-}
 {-# Language TypeFamilies #-}
 {-# Language TypeInType #-}
 {-# Language TypeOperators #-}

 import Data.Kind

 data DEFUNC :: Type -> Type -> Type where
   (:~>) :: a -> b -> DEFUNC a b

 type a ~> b = DEFUNC a b -> Type

 data LamCons a :: Type ~> Type where
   LamCons :: a -> LamCons a ([a] :~> [a])

 class Mk (app :: Type ~> Type) where
   type Arg app :: Type

   mk :: Arg app -> app (a :~> b)

 instance Mk (LamCons a :: Type ~> Type) where
   type Arg (LamCons a) = a

   mk :: a -> LamCons (a :~> b)
   mk = LamCons
 }}}

 erros with `ghci -ignore-dot-ghci -fdefer-type-errors -dcore-lint bug.hs`
 on GHC 8.2.1 and 8.3.20171208.

-- 
Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14607
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