[GHC] #11375: Type aliases twice as slow to compile as closed type families.

[GHC]

#11375: Type aliases twice as slow to compile as closed type families.
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        Reporter:  danilo2           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  MacOS X           |         Architecture:  aarch64
 Type of failure:  Compile-time      |            Test Case:
  performance bug                    |
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 That is mysterious.  I have absolutely no idea what is happening.  So a
 way to reproduce would indeed be useful!

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11375#comment:3>
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