[GHC] #8095: TypeFamilies painfully slow

[GHC]

#8095: TypeFamilies painfully slow
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        Reporter:  MikeIzbicki                   |            Owner:
            Type:  bug                           |           Status:  new
        Priority:  normal                        |        Milestone:
       Component:  Compiler (Type checker)       |          Version:  7.6.3
      Resolution:                                |         Keywords:
Operating System:  Unknown/Multiple              |     Architecture:
 Type of failure:  Compile-time performance bug  |  Unknown/Multiple
       Test Case:                                |       Difficulty:
        Blocking:                                |  Unknown
                                                 |       Blocked By:
                                                 |  Related Tickets:  5321
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Comment (by goldfire):

 I've been playing around with type families recently, so I just took a
 look at this one. I can reproduce Mike's observed behavior exactly, both
 with 7.6.3 and with HEAD (although I had to strike the "`import
 GHC.TypeLits`" to get the produced file to compile with HEAD). It seems
 that the problem lies outside the area I've been editing, so I'm going to
 leave this for now.

 For what it's worth, I tried this example with closed type families, and
 the resultant behavior is the same. This leads me to believe the problem
 is indeed in the constraint solver.

 Thanks for reporting and for creating a great test environment!

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8095#comment:1>
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