tc124 fails as '*** Core Lint errors : in result of Simplifier ***' in WAY=optasm

ghc-HEAD:

$ make fulltest TEST="tc124" WAY=optasm

=====> tc124(optasm) 3136 of 4101 [0, 0, 0] 
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 tc124.hs -O -fasm  -fno-warn-incomplete-patterns >tc124.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 -> a_aia -> a_aia’
    @ a_12 is out of scope
*** Offending Program ***
Foo.g :: Foo.T -> Foo.T
[LclIdX,
 Arity=1,
 Str=DmdType,
 Unf=Unf{Src=<vanilla>, TopLvl=True, Value=True, ConLike=True,
         WorkFree=True, Expandable=True, Guidance=IF_ARGS [20] 40 30}]
Foo.g =
  \ (t_ahr :: Foo.T) ->
    case t_ahr of _ [Occ=Dead] { Foo.T ds_dlB ds_dlC ->
    Foo.T
      ds_dlB
      (\ (@ a_ai4) (@ b_ai5) _ [Occ=Dead] (y_aht :: b_ai5) -> y_aht)
    }
...

Trac metadata

Trac field	Value
Version	7.9
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case	tc124
Differential revisions
BlockedBy
Related
Blocking
CC	simonpj
Operating system
Architecture