[GHC] #13715: test dynamic-paper for way profasm fails with Simplifier ticks exhausted

[GHC]

#13715: test dynamic-paper for way profasm fails with Simplifier ticks exhausted
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        Reporter:  George            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  Research
                                     |  needed
       Component:  Compiler          |              Version:  8.2.1-rc2
      Resolution:                    |             Keywords:  simplifier
                                     |  ticks
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:  dynamic-paper
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by simonpj):

 * milestone:   => Research needed


Comment:

 Aha!  Dimitrios and I identified this problem with `TypeRep`, and wrote
 about this in Section 7 of [https://www.microsoft.com/en-
 us/research/publication/typed-reflection-in-haskell/ Typed reflection in
 Haskell].  This example probably comes straight from that section.

 Divergence is absolutely expected here; and the simplifier-tick mechanism
 correctly prevents the compiler from hanging.

 Of course, it would be better to spot the problem and not inline the
 function, but I don't know how to do that.  An interesting research
 problem.

 Meanwhile, since there is no immediate prospect of solving this, and it's
 not causing any problems in practice, I'll move to milestone "research
 needed".

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13715#comment:2>
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