[GHC] #12479: build fail of commercialhaskell.com with stack build on mac os x sierra beta 4

[GHC]

#12479: build fail of commercialhaskell.com with stack build on mac os x sierra
beta 4
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        Reporter:  stephenb          |                Owner:
            Type:  bug               |               Status:  infoneeded
        Priority:  normal            |            Milestone:  8.0.2
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  MacOS X           |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #12198            |  Differential Rev(s):  Phab:D2532
       Wiki Page:                    |
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Comment (by duncan):

 > This is kind of a hack that relies on the directory structure that Cabal
 produces to be effective, but it has the advantage of being a local
 change. Cabal would also need some similar change in order for the final
 libraries that it links to be loadable.

 Unfortunately, in general it is the user/builder calling Cabal that gets
 to choose the layout, so it's hard to pick a fixed scheme.

 That said, we can in principle compute an optimal (or near-optimal) set of
 shared prefixes. We start with the info from the ghc-pkg db
 (InstalledPackageInfo) which has the full path to the libraries (or enough
 info to compute it). Then we would take the set of those paths, make a
 trie, count the number of elements beneath each trie node and take as
 shared prefixes all the ones with a count of > 1. Or something like that.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12479#comment:20>
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