[GHC] #7386: Panic "tcTyVarDetails" in GHCi when :forcing a data family instance

[GHC]

#7386: Panic "tcTyVarDetails" in GHCi when :forcing a data family instance
------------------------------+---------------------------------------------
 Reporter:  goldfire          |          Owner:                  
     Type:  bug               |         Status:  new             
 Priority:  normal            |      Component:  GHCi            
  Version:  7.6.1             |       Keywords:  PolyKinds       
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  GHCi crash        |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
------------------------------+---------------------------------------------

Comment(by simonpj@…):

 commit acbe5265d053e6497626f12f49f38aa31ff730e5
 {{{
 Author: Simon Peyton Jones <simonpj at microsoft.com>
 Date:   Tue Nov 6 15:55:39 2012 +0000

     Fix the instantiation of data constructors in the GHCi debugger

     This bug caused Trac #7386, because in the (rather tricky) "type
     inference" (aka run time type reconstruction) done by the GHCi
     debugger, we were failing to instantiate a data type family
     correctly.  When that code was written we didn't *have* data
     families.

     I wrote Note [Constructor arg types] to explain the new scheme.

  compiler/ghci/RtClosureInspect.hs |   39
 ++++++++++++++++++++++++++++++++----
  1 files changed, 34 insertions(+), 5 deletions(-)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7386#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler