#6068: Panic in GHCi when using functional dependencies and promoted kinds
------------------------------+---------------------------------------------
 Reporter:  goldfire          |          Owner:                  
     Type:  bug               |         Status:  new             
 Priority:  normal            |      Component:  GHCi            
  Version:  7.5               |       Keywords:  PolyKinds       
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  GHCi crash        |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
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Comment(by simonpj@…):

 commit 969f8b728be0a2fec8263e8866295776c993394b
 {{{
 Author: Simon Peyton Jones <[email protected]>
 Date:   Wed May 16 11:13:52 2012 +0100

     Be careful to instantiate kind variables when dealing with functional
 dependencies

     There were really two bugs
       a) When the fundep fires we must apply the matching
          substitution to the kinds of the remaining type vars
          (This happens in FunDeps.checkClsFD, when we create meta_tvs)

       b) When instantiating the un-matched type variables we must
          instantiate their kinds properly
          (This happens in TcSMonad.instFlexiTcS)

     This fixes #6068 and #6015 (second reported bug).

  compiler/typecheck/TcInteract.lhs |    6 +--
  compiler/typecheck/TcSMonad.lhs   |    8 +++-
  compiler/types/FunDeps.lhs        |   87
 ++++++++++++++++++++++---------------
  3 files changed, 60 insertions(+), 41 deletions(-)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6068#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler

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