[GHC] #13059: High memory usage during compilation

[GHC]

#13059: High memory usage during compilation
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        Reporter:  domenkozar        |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.2-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * cc: simonpj (added)


Comment:

 The question now is: how was GHC generating default instance methods prior
 to 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060? Perhaps there's a way we
 could go back to the way the code was generated while preserving the
 typechecking benefits of 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060.

 Simon, do you recall how this worked prior to
 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060? Unfortunately, `-ddump-deriv`
 didn't show the generated code for default instance methods prior to
 54b887b5abf6ee723c6ac6aaa2d2f4c14cf74060, so it's hard for me to figure
 out what happened before.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13059#comment:18>
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