[GHC] #14978: GADTs don't seem to unpack properly

[GHC]

#14978: GADTs don't seem to unpack properly
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        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"9187d5fb1d3d38a4e607b0d61784c21447c8195b/ghc"
 9187d5fb/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="9187d5fb1d3d38a4e607b0d61784c21447c8195b"
 Allow unpacking of single-data-con GADTs

 Trac #14978 pointed out that single-constructor GADTs should be
 unpackable without trouble.

 Acutally I realise that even existentials should be unpackable
 too, but that's a bit more work, so it's not part of this patch.

 See Note [Unpacking GADTs and existentials] in MkId.
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14978#comment:1>
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