[GHC] #11600: Panic (ASSERT failed) in compiler/types/TyCoRep.hs:1939

[GHC]

#11600: Panic (ASSERT failed) in compiler/types/TyCoRep.hs:1939
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        Reporter:  hvr               |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by hvr):

 Replying to [comment:1 simonpj]:
 > How precisely does one reproduce, starting from HEAD?

 What should work (on Linux at least):

 {{{
 git checkout wip/transformers-0.5.2
 git submodule update
 ./validate --fast
 }}}

 If you look at `git show wip/transformers-0.5.2` you'll notice that the
 only thing needed is to update the transformers submodule and silence a
 warning accidentally introduced by `transformers`:

 {{{#!diff
 diff --git a/libraries/transformers b/libraries/transformers
 index a2f7dd0..10348c4 160000
 --- a/libraries/transformers
 +++ b/libraries/transformers
 @@ -1 +1 @@
 -Subproject commit a2f7dd057a0ee0c6cb206609594d7a07d26a1861
 +Subproject commit 10348c4bbf60debbfc82463e1035aca1cb7b51bc
 diff --git a/mk/warnings.mk b/mk/warnings.mk
 index 10c0935..63388fb 100644
 --- a/mk/warnings.mk
 +++ b/mk/warnings.mk
 @@ -104,6 +104,7 @@ libraries/dph/dph-lifted-common-install_EXTRA_HC_OPTS
 += -Wwarn
  libraries/transformers_dist-boot_EXTRA_HC_OPTS += -fno-warn-unused-
 matches -fno-warn-unused-imports
  libraries/transformers_dist-install_EXTRA_HC_OPTS += -Wno-unused-matches
 -Wno-unused-imports
  libraries/transformers_dist-install_EXTRA_HC_OPTS += -Wno-redundant-
 constraints
 +libraries/transformers_dist-install_EXTRA_HC_OPTS += -Wno-orphans

  # Turn of trustworthy-safe warning
  libraries/base_dist-install_EXTRA_HC_OPTS += -Wno-trustworthy-safe
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11600#comment:2>
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