[GHC] #11664: Core Lint failure when building warp-3.2.2

[GHC]

#11664: Core Lint failure when building warp-3.2.2
------------------------------------+--------------------------------------
        Reporter:  anton.dessiatov  |                Owner:
            Type:  bug              |               Status:  new
        Priority:  normal           |            Milestone:
       Component:  Compiler         |              Version:  7.10.3
      Resolution:                   |             Keywords:
Operating System:  Linux            |         Architecture:  x86_64 (amd64)
 Type of failure:  None/Unknown     |            Test Case:
      Blocked By:                   |             Blocking:
 Related Tickets:                   |  Differential Rev(s):
       Wiki Page:                   |
------------------------------------+--------------------------------------

Comment (by anton.dessiatov):

 I (expectedly) failed to make stack work with lts-5.5 and GHC 8.0 rc2 so I
 resorted to using cabal. I have used cabal-install 1.22.8.0 built against
 1.22.7.0 Cabal library by GHC 7.10.3 to build warp 3.2.2 with GHC 8.0 rc2.

 I have did the following (ensuring that correct GHC 8.0 rc2 is on my PATH
 and I'm in a directory with Warp 3.2.2 source code)
 {{{
 cabal update
 cabal sandbox init
 cabal install --ghc-options -dcore-lint
 }}}

 This time it failed when building `attoparsec-0.13.0.1`
 (Data.Attoparsec.Text.Internal module). Now it says
 {{{
 *** Core Lint errors : in result of SpecConstr ***
 <no location info>: warning:
     In the type ‘Buffer
                  -> Pos -> More -> a_aNxE -> IResult Text r_aNxF’
     @ a_aNxE is out of scope
 }}}

 The full output is huge so I gzipped it (will post after submitting this
 message).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11664#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler