Re: [GHC] #10179: Kinds missing from types in ghci

23 Mar 2015


      #10179: Kinds missing from types in ghci
-------------------------------------+-------------------------------------
        Reporter:  br1               |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  GHCi              |                 Version:  7.10.1-rc2
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
Description changed by simonpj:

Old description:
...
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE PolyKinds #-}
data family F (a:: k)
foo :: F (m :: [()]) -> a
foo = undefined
bar :: F (m :: [[()]]) -> a
bar = undefined
according to GHCi, both foo and bar have type F m -> a but [foo, bar]
fails
New description:

 {{{
 {-# LANGUAGE TypeFamilies #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE PolyKinds #-}

 data family F (a:: k)

 foo :: F (m :: [()]) -> a
 foo = undefined
 bar :: F (m :: [[()]]) -> a
 bar = undefined
 }}}
 according to GHCi, both `foo` and `bar` have type `F m -> a` but `[foo,
 bar]` fails

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10179#comment:1
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