[GHC] #13338: New versions of time and Cabal are causing a Core Lint error on Windows

[GHC]

#13338: New versions of time and Cabal are causing a Core Lint error on Windows
-------------------------------------+-------------------------------------
           Reporter:  rwbarton       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  highest        |         Milestone:  8.2.1
          Component:  Compiler       |           Version:  8.1
           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:
-------------------------------------+-------------------------------------
 Commit c8d995db5d743358b0583fe97f8113bf9047641e in ghc bumped the `time`
 submodule to the latest version 4eb06c0e (`time-1.8`). But it caused a
 Core Lint error while compiling `Distribution.Compat.Time`, in the Cabal
 library:

 {{{
 *** Core Lint errors : in result of Float out(FOS {Lam = Just 0,
                                                    Consts = True,
                                                    OverSatApps = True})
 ***
 <no location info>: warning:
     In the expression: $wsystemToUTCTime
                          (case lvl_sdDL of v_B1 { I# v_B2 -> v_B2 })
                          (case lvl_sdDM of v_B1 { W# v_B2 -> v_B2 })
     This argument does not satisfy the let/app invariant:
       case lvl_sdDL of v_B1 { I# v_B2 -> v_B2 }
 }}}

 See https://phabricator.haskell.org/harbormaster/build/21371/ for the full
 build log.

 For now the submodule bumps have been reverted.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13338>
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