[GHC] #12212: GHC 8.0.1 crash

[GHC]

#12212: GHC 8.0.1 crash
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        Reporter:  dibblego          |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  9160, 10602       |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"d09e982c534b20908064f36d701a1a3a6a2eb55a/ghc"
 d09e982c/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="d09e982c534b20908064f36d701a1a3a6a2eb55a"
 Don't quantify over Refl in a RULE

 This fixes Trac #12212.  It's quite hard to provoke, but I've
 added a standalone test case that does so.

 The issue is explained in Note [Evidence foralls] in Specialise.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12212#comment:5>
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