[GHC] #13963: Runtime representation confusingly displayed

[GHC]

#13963: Runtime representation confusingly displayed
-------------------------------------+-------------------------------------
           Reporter:  Iceland_jack   |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 8.3.20170605:

 {{{
 > :set -XRankNTypes -XTypeInType
 > import GHC.Exts (TYPE, RuntimeRep(LiftedRep))
 > type Pair (a::TYPE rep) (b::TYPE rep') rep'' = forall (r::TYPE rep'').
 (a -> b -> r) -> r
 > :kind Pair
 Pair :: * -> * -> *
 > :kind Pair Int
 Pair Int :: * -> *
 > :kind Pair Int Float
 Pair Int Float :: *
 > :kind Pair Int Float LiftedRep
 Pair Int Float LiftedRep :: *
 }}}

 It still behaves oddly with `-fprint-explicit-runtime-reps` enabled

 {{{
 > :set -fprint-explicit-runtime-reps
 > :kind Pair
 Pair :: * -> * -> forall (rep'' :: RuntimeRep) -> *
 > :kind Pair Int
 Pair Int :: * -> forall (rep'' :: RuntimeRep) -> *
 > :kind Pair Int Float
 Pair Int Float :: *
 > :kind Pair Int Float LiftedRep
 Pair Int Float LiftedRep :: *
 }}}

 I would have also expected to see `Pair`'s kind displayed something like
 this

 {{{#!hs
 forall {rep :: RuntimeRep} {rep' :: RuntimeRep}. TYPE rep -> TYPE rep' ->
 forall (rep'' :: RuntimeRep) -> *
 }}}

 which is how the kind of the corresponding `newtype` gets displayed

 {{{
 > newtype Pair2 (a::TYPE rep) (b::TYPE rep') rep'' = P2 (forall (r::TYPE
 rep''). (a -> b -> r) -> r)
 > :kind Pair2
 Pair2 :: forall {rep :: RuntimeRep} {rep' :: RuntimeRep}.
          TYPE rep -> TYPE rep' -> forall (rep'' :: RuntimeRep) -> *
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13963>
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