[GHC] #11694: The function `lift'ghc: panic! (the 'impossible' happened)

[GHC]

#11694: The function `lift'ghc: panic! (the 'impossible' happened)
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           Reporter:  Sventimir      |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  7.10.3
           Keywords:                 |  Operating System:  Linux
       Architecture:  x86_64         |   Type of failure:  Compile-time
  (amd64)                            |  crash
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 The error message I got doesn't even make much sense (or at least I don't
 understand it). Here it is:

 {{{
 src/Splices.hs:22:18:
     Couldn't match kind `* -> *' with `*'
     Expected type: (a1 -> a1)
                    ->
 heist-0.14.1.1:Heist.Internal.Types.HeistState.HeistT m m Text
       Actual type: (a1 -> a1)
                    ->
 heist-0.14.1.1:Heist.Internal.Types.HeistState.HeistT m m Text
     Kind incompatibility when matching types:
       a_t -> a_t :: * -> *
       a1 -> a1 :: *
     The function `lift'ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for x86_64-unknown-linux):
         kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d}

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

 As far as I understand it says that two things of the same type (a -> a)
 have different kind...

 And the offending function is really simple:

 {{{#!hs
 import Happstack.Server (path)
 import Heist.Interpreted (textSplice)


 insertFromPath :: Splice m
 insertFromPath = lift path id >>= textSplice
 }}}

 I believe that `m` should evaluate to `ServerPartT IO` from
 Happstack.Server module. I append the whole source code.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11694>
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