[GHC] #15108: Panic: collectNBinders

[GHC]

#15108: Panic: collectNBinders
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        Reporter:  cdisselkoen       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Profiling         |              Version:  8.4.2
      Resolution:                    |             Keywords:  panic
                                     |  collectNBinders
Operating System:  Linux             |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"d4cc74f1a5d1aafc8a2fde3c80019e2ef88d146b/ghc" d4cc74f/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="d4cc74f1a5d1aafc8a2fde3c80019e2ef88d146b"
 Preserve join-point arity in CoreOpt

 Trac #15108 showed that the simple optimiser in CoreOpt
 was accidentally eta-reducing a join point, so it didn't meet
 its arity invariant.

 This patch fixes it.  See Note [Preserve join-binding arity].
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15108#comment:8>
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