[GHC] #9291: Don't reconstruct sum types if the type subtly changes

[GHC]

#9291: Don't reconstruct sum types if the type subtly changes
-------------------------------------+-------------------------------------
        Reporter:  schyler           |                Owner:  nomeata
            Type:  feature request   |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.8.2
      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):  Phab:D2871
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by nomeata):

 * status:  new => patch


Comment:

 Ok, should be ready for review.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9291#comment:41>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler