[GHC] #9566: T7891 fails as '*** Core Lint errors : in result of Simplifier ***' in WAY=optasm

[GHC]

#9566: T7891 fails as '*** Core Lint errors : in result of Simplifier ***' in
WAY=optasm
-------------------------------------+-------------------------------------
       Reporter:  slyfox             |                   Owner:
           Type:  bug                |                  Status:  new
       Priority:  normal             |               Milestone:
      Component:  Compiler           |                 Version:  7.9
       Keywords:                     |        Operating System:
   Architecture:  x86_64 (amd64)     |  Unknown/Multiple
     Difficulty:  Unknown            |         Type of failure:  GHC
     Blocked By:                     |  rejects valid program
Related Tickets:                     |               Test Case:
                                     |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
 ghc-HEAD:
 {{{
 $ make fulltest TEST="T7891" WAY=optasm

 cd ./typecheck/should_compile && '/home/slyfox/dev/git/ghc-
 validate/inplace/bin/ghc-stage2' -fforce-recomp -dcore-lint -dcmm-lint
 -dno-debug-output -no-user-package-db -rtsopts -fno-ghci-history -c
 T7891.hs -O -fasm  -fno-warn-incomplete-patterns >T7891.comp.stderr 2>&1
 Compile failed (status 256) errors were:
 *** Core Lint errors : in result of Simplifier ***
 <no location info>: Warning:
     In the type ‘a_12 -> t_aiF -> t_aiF’
     @ a_12 is out of scope
 *** Offending Program ***
 T7891.tf :: T7891.T
 [LclIdX,
  Arity=1,
  Str=DmdType,
  Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
          WorkFree=True, Expandable=True,
          Guidance=ALWAYS_IF(arity=0,unsat_ok=True,boring_ok=True)}]
 T7891.tf =
   GHC.Base.id
   `cast` (Sym T7891.NTCo:T[0]
           :: (forall t_ahj. t_ahj -> t_ahj) ~R# T7891.T)

 T7891.f :: forall t_ahw. t_ahw -> t_ahw
 [LclIdX,
  Arity=1,
  Str=DmdType,
  Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
          WorkFree=True, Expandable=True,
          Guidance=ALWAYS_IF(arity=0,unsat_ok=True,boring_ok=True)}]
 T7891.f =
   T7891.tf
   `cast` (T7891.NTCo:T[0]
           :: T7891.T ~R# (forall t_ahj. t_ahj -> t_ahj))
 ...
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9566>
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