[GHC] #7175: Panic when wrongly using a type family as return types for GADTs

[GHC]

#7175: Panic when wrongly using a type family as return types for GADTs
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        Reporter:  goldfire          |         Owner:
            Type:  bug               |        Status:  closed
        Priority:  normal            |     Milestone:  7.6.1
       Component:  Compiler          |       Version:  7.6.1-rc1
      Resolution:  fixed             |      Keywords:
Operating System:  Unknown/Multiple  |  Architecture:  Unknown/Multiple
 Type of failure:  Compile-time      |     Test Case:
  crash                              |  typecheck/should_fail/T7175
      Blocked By:                    |      Blocking:
 Related Tickets:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"a870738a3b34d264c63656783e84168a230d7da4/ghc" a870738/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="a870738a3b34d264c63656783e84168a230d7da4"
 Improve rejigConRes (again)

 I think this patch finally works around the delicacy in the strictness
 of TcTyClsDecls.rejigConRes.   See the notes with that function and
 Note [Checking GADT return types].

 As a result, we fix Trac #10836, and improve Trac #7175
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7175#comment:4>
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