[GHC] #9220: type roles for unboxed arrays

[GHC]

#9220: type roles for unboxed arrays
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              Reporter:  rwbarton    |            Owner:  goldfire
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  7.10.1
             Component:  Core        |          Version:  7.8.1
  Libraries                          |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:              |  Related Tickets:
  None/Unknown                       |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by goldfire):

 See my WIP commit [https://github.com/ghc/packages-
 array/commit/86225ba71603ed73a338e5f658698fc87aadcae9 here].

 In the end, I have little idea what I'm doing here -- I was just
 implementing the fix I thought we had agreed on (but never concretely
 articulated), which is to make the element parameter to all the types
 mentioned in the initial report have a nominal role. Reid does seem to say
 in comment:8, upon closer inspection, that `UArray` should keep its
 representational role. But I'd love for him to chime in here.

 I'll do what I'm told on this one!

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9220#comment:13>
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