[GHC] #8531: ghc crash from kinds

[GHC]

#8531: ghc crash from kinds
-----------------------------------+---------------------------------------
       Reporter:  guest            |             Owner:
           Type:  bug              |            Status:  new
       Priority:  lowest           |         Milestone:
      Component:  Compiler         |           Version:  7.6.3
       Keywords:                   |  Operating System:  MacOS X
   Architecture:                   |   Type of failure:  Compile-time crash
  Unknown/Multiple                 |         Test Case:
     Difficulty:  Unknown          |          Blocking:
     Blocked By:                   |
Related Tickets:                   |
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 When I run this in ghci:


 {{{
 let x :: MaybeT IO (Ptr Int);  x = (lift newCString "hi")  >>=
 nullableToMaybeT
 }}}

 I get this output:

 {{{
     Couldn't match kind `* -> *' with `*'
     Expected type: [Char] -> MaybeT IO (Ptr Int)
       Actual type: [Char] -> MaybeT IO (Ptr Int)
     Kind incompatibility when matching types:
       [Char] :: * -> *
       [Char] :: *
     The function `lift'ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for x86_64-apple-darwin):
         kindFunResult
 <<details unavailable>>
 }}}

 where nullToMaybeT is:
 {{{
 nullableToMaybeT :: Monad m => Ptr a -> MaybeT m (Ptr a)
 nullableToMaybeT ptr = do
   case (ptr == nullPtr) of
     True ->  (MaybeT . return) Nothing
     False -> return ptr
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8531>
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