[GHC] #7778: kindFunResult panic with => inside a constraint

[GHC]

#7778: kindFunResult panic with => inside a constraint
----------------------------------------+-----------------------------------
    Reporter:  monoidal                 |       Owner:  simonpj         
        Type:  bug                      |      Status:  new             
    Priority:  normal                   |   Milestone:  7.8.1           
   Component:  Compiler (Type checker)  |     Version:  7.6.2           
    Keywords:                           |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple         |     Failure:  None/Unknown    
  Difficulty:  Unknown                  |    Testcase:                  
   Blockedby:                           |    Blocking:                  
     Related:                           |  
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Comment(by parcs):

 FYI the first code snippet produces a different panic with a DEBUG build
 of GHC.

 Panic with DEBUG build:
 {{{
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 7.7.20130416 for x86_64-unknown-linux):
         ASSERT failed!
     file compiler/types/Type.lhs line 1623
     base:GHC.Num.Num{tc 2b} ghc-prim:GHC.Types.Int{(w) tc 3J} =>
     base:GHC.Num.Num{tc 2b}
     ghc-prim:GHC.Prim.*{(w) tc 34d}
     -> ghc-prim:GHC.Prim.Constraint{(w) tc 34s}

 }}}

 Panic with non-DEBUG buird:
 {{{
 [1 of 1] Compiling Main             ( q.hs, interpreted )
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 7.7.20130421 for x86_64-unknown-linux):
         kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d}
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7778#comment:2>
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