[GHC] #10665: INLINE breaks rewrite rules when '-g' is used

[GHC]

#10665: INLINE breaks rewrite rules when '-g' is used
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        Reporter:  slyfox            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.2-rc2
  (CodeGen)                          |
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by slyfox):

 (side note: I'm not an author of those packages, just a mere distribution
 packager :))

 conduit is a big package, i'll try to prepare self-contained bundle
 to ease analysis of existing RULES in there.

 Meanwhile I've found smaller package that fails in similar way:
 unification-fd-0.10.0.1.

 The plus is that everything happens in a single module
 '''Data.Functor.Fixedpoint'''.

 The failure is:
 {{{
 $ ghc -hide-all-packages -package=base -O2 -c -g Fixedpoint.hs
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.10.2 for x86_64-unknown-linux):
         Tick in rule eps_aPv @ (Fix f_aPy) (unFix @ f_aPy x_a2gY)

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 (Or with -dsuppress-uniques:)
         Tick in rule eps @ (Fix f) (unFix @ f x)
 }}}

 Would it be easy to add actual rule name to that crash to ease analysis
 of what exactly went wrong? (Or maybe there already is a trace knob for
 it?)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10665#comment:2>
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