[GHC] #12746: Assertion failed with BuildFlavour = devel2 (one more)

[GHC]

#12746: Assertion failed with  BuildFlavour = devel2 (one more)
-------------------------------------+-------------------------------------
        Reporter:  pacak             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by rwbarton):

 I couldn't reproduce this with the released GHC 8.0.1. Do you think it
 only happens with devel2 builds? Any idea why?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12746#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler