[GHC] #13994: STG lint failure on master

[GHC]

#13994: STG lint failure on master
-------------------------------------+-------------------------------------
           Reporter:  bgamari        |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  high           |         Milestone:  8.4.1
          Component:  Compiler       |           Version:  8.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 As of 4700baaf8f9bf3c44a53a595d840c7c14cfd6f98 building with this
 `build.mk` results in an STG lint failure,

 {{{
 BuildFlavour = devel2
 include mk/flavours/$(BuildFlavour).mk

 GhcLibHcOpts += -g3 -ddump-to-file -ddump-stg -dcore-lint -dstg-lint
 -dcmm-lint
 GhcRtsHcOpts += -g3
 GhcStage2HcOpts += -g3 -ddump-to-file -ddump-stg -dcore-lint -dstg-lint
 -dcmm-lint
 }}}

 The failures occurs while building `libraries/integer-gmp/dist-
 install/build/GHC/Integer/Type.o` and are of the form,
 {{{
           *** Stg Lint ErrMsgs: in Stg2Stg ***
   <no location info>: warning:
        [in body of lambda with binders m0_scBi :: State# s_a2Ej
                                                   -> State# s_a2Ej,
                                        s1_scBj :: State# s_a2Ej]
       s'_scBk is out of scope
   <no location info>: warning:
        [RHS of $j1_sdij :: (# BigNat, GmpLimb# #)]
       Let(rec) binder ‘$j1_sdij’ has unlifted type ‘(# BigNat,
                                                        GmpLimb# #)’
       RHS: (elided for brevity)

  <no location info>: warning:
        [RHS of $j4_sdQ1 :: (# BigNat, BigNat #)]
       Let(rec) binder ‘$j4_sdQ1’ has unlifted type ‘(# BigNat, BigNat #)’
       RHS: (elided)
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13994>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler