[GHC] #8882: internal error (deriving generic / cyclical imports?)

[GHC]

#8882: internal error (deriving generic / cyclical imports?)
-------------------------------+----------------------------------
        Reporter:  mf825       |            Owner:
            Type:  bug         |           Status:  new
        Priority:  normal      |        Milestone:
       Component:  Compiler    |          Version:  7.6.3
      Resolution:              |         Keywords:  panic
Operating System:  Linux       |     Architecture:  x86_64 (amd64)
 Type of failure:  GHCi crash  |       Difficulty:  Unknown
       Test Case:              |       Blocked By:
        Blocking:              |  Related Tickets:
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Comment (by thoughtpolice):

 This seems to be fixed in 7.8.1. Using 7.8.1-rc2, running `crash.sh` I
 get:

 {{{
 $ ./crash.sh
 ... lots of stuff ...
 Loading package profunctors-4.0.2 ... linking ... done.
 Loading package reflection-1.4 ... linking ... done.
 Loading package split-0.2.2 ... linking ... done.
 Loading package void-0.6.1 ... linking ... done.
 Loading package lens-4.0.5 ... linking ... done.
 [1 of 5] Compiling Adhocracy.DataModel.Types (
 src/Adhocracy/DataModel/Types.hs, interpreted )
 [2 of 5] Compiling Adhocracy.Types  ( src/Adhocracy/Types.hs, interpreted
 )
 [3 of 5] Compiling Adhocracy.DataModel.Universes[boot] (
 src/Adhocracy/DataModel/Universes.hs-boot, interpreted )
 [4 of 5] Compiling Adhocracy.DataModel.Default (
 src/Adhocracy/DataModel/Default.hs, interpreted )
 [5 of 5] Compiling Adhocracy.DataModel.Universes (
 src/Adhocracy/DataModel/Universes.hs, interpreted )
 Ok, modules loaded: Adhocracy.DataModel.Default,
 Adhocracy.DataModel.Types, Adhocracy.DataModel.Universes,
 Adhocracy.DataModel.Universes, Adhocracy.Types.
 *Adhocracy.DataModel.Default> *Adhocracy.DataModel.Default
 Adhocracy.DataModel.Default>
 Top level: Not in scope: data constructor ‘WDF’
 }}}

 The last error message looks like a bug in your script since I have no
 idea where `WDF` is supposed to come from.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8882#comment:1>
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