[GHC] #8095: TypeFamilies painfully slow

[GHC]

#8095: TypeFamilies painfully slow
-------------------------------------+-------------------------------------
        Reporter:  MikeIzbicki       |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  Compiler (Type    |              Version:  7.6.3
  checker)                           |
      Resolution:                    |             Keywords:  TypeFamilies
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #5321, #11598,    |  Differential Rev(s):  Phab:D3752,
  #12506, #13386                     |  Phab:D4766
       Wiki Page:                    |
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Comment (by _recursion):

 Is there any chance that this will be able to make it into 8.6? We
 ([https://www.luna-lang.org/ Luna]) have a codebase that is ''very'' heavy
 on type families, and we're seeing obscene compile times and memory usage
 when building with optimisation. When it takes longer to compile than ghc
 in the `perf` build flavour, we have ''something'' wrong!

 I'd have tried the patch (D4766) myself, but it's currently not able to
 apply without conflict resolution to either the `master` or `ghc-8.6`
 branches, and I don't want to risk mucking something up trying to resolve
 conflicts!

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8095#comment:51>
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