[GHC] #14558: Unable to parse integer-gmp's Cabal file

[GHC]

#14558: Unable to parse integer-gmp's Cabal file
-------------------------------------+-------------------------------------
        Reporter:  taylorfausak      |                Owner:  hvr
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Core Libraries    |              Version:  8.2.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by taylorfausak):

 (1) is correct. As far as I can tell, the Cabal files on Hackage match the
 Cabal files in the GHC repository. This is good and I'm happy that it
 happened, but it's not why I opened this ticket.

 (2) is also correct. GHC and its built-in libraries require Cabal 2. This
 is obviously fine for GHC itself, but any downstream clients using GHC <
 8.2 or Cabal < 2 are broken by this. (For example:
 https://github.com/tfausak/grawlix/commit/861f0f9d3f19ae9d94ce11b52311459e5a656534#commitcomment-25680505.)

 I don't think we are stuck with this problem for 8.2. As far as Stack <
 1.6.1 is concerned, revising the `integer-gmp-1.0.1.0` release or
 releasing a new version of `integer-gmp` would fix things. Specifically,
 removing the caret constraint (and relaxing the `cabal-version`) would
 allow older versions of Cabal and Stack to successfully parse `integer-
 gmp.cabal`. The patch is pretty small:
 https://github.com/ghc/ghc/commit/82aae8c81f5380af5f5ab9c381b1d296104696f4

 For what it's worth, I ran into this problem because Stack 1.5.1 ships
 with Cabal 1.24. I have fixed this problem for myself by upgrading to
 Stack 1.6.1. Anybody still using Stack < 1.6.1 will be broken if they try
 to use a snapshot with GHC >= 8.2. This includes anyone using the Haskell
 Platform, which bundles Stack 1.5.1.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14558#comment:18>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler