[GHC] #4012: Compilation results are not deterministic

[GHC]

#4012: Compilation results are not deterministic
-------------------------------------+-------------------------------------
        Reporter:  kili              |                   Owner:  niteria
            Type:  bug               |                  Status:  patch
        Priority:  high              |               Milestone:  8.0.1
       Component:  Compiler          |                 Version:  6.12.2
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:  Phab:D910,
                                     |  Phab:D1073, Phab:D1133, Phab:D1192
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Comment (by meteficha):

 Assuming that the main source of non-deterministic Uniques is the non-
 deterministic, lazy I/O, how about making a different Unique "namespace"
 for each file?  Conceptually, it would mean having:

 {{{#!hs
 data Unique = MkUnique {-# UNPACK #-} !Int (Maybe ModuleName)
 }}}

 There could still be problems if each file was processed in a non-
 deterministic way, but now files could be processed in any order without
 changing the Uniques.

 This is of course an extremely naive suggestion, I'm sharing it with the
 hope that it may spark some better idea in someone else's mind :).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:119>
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