[GHC] #15703: Significant compilation time blowup when refactoring singletons-heavy code

[GHC]

#15703: Significant compilation time blowup when refactoring singletons-heavy code
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.6.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15725            |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * related:   => #15725


Comment:

 I don't know if this is related to the performance issue witnessed here,
 but it turns out that `Lib.hs` compiles cleanly with `-dcore-lint -O0`,
 but crashes with `-dcore-lint -O1`. I've opened #15725 for this.
 (Interestingly, in the more minimal example I provide in #15725, the Core
 Lint error happens regardless of optimization level.)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15703#comment:7>
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