[GHC] #15908: Hadrian: Spurious build failure on fresh build

[GHC]

#15908: Hadrian: Spurious build failure on fresh build
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        Reporter:  heisenbug         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Build System      |              Version:  8.7
  (Hadrian)                          |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Building GHC      |  Unknown/Multiple
  failed                             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by heisenbug):

 I see.

 You should be able to reproduce the `GHC.Prim` issue by `git reset --hard
 36fcf9edee~1` (be sure to check `git status` first, and save all your
 work). Now zap your `_build` and redo it. Then `git reset --hard
 36fcf9edee` and do an incremental build. This should result in the same
 error. The reason is probably that when new primitives are introduced,
 some generators (`genPrim` or such?) need to run.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15908#comment:4>
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