[GHC] #14574: Template Haskell Uniq ~ Int leads to external interpreter cross compilation trouble

[GHC]

#14574: Template Haskell Uniq ~ Int leads to external interpreter cross compilation
trouble
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        Reporter:  luite             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.3
      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:                    |
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Comment (by luite):

 Replying to [comment:6 RyanGlScott]:
 > Replying to [comment:5 luite]:
 > > Changing it to `type Uniq = Integer` turned out to be easiest because
 GHC doesn't know the data constructor for `Int64`.
 >
 > What do you mean by this?

 GHC doesn't have the `GHC.Int.I64#` data constructor as a known name in
 `PrelNames`

 > > And I think `Integer` is actually more appropriate here.
 >
 > I'm sure `Integer` technically works, but I am worried that we'd lose
 some efficiency by doing this, given how widely used `Name`s are in
 Template Haskell.

 I think in practice it would not make much of a difference in situations
 that were already supported (i.e. target word size is the same as compiler
 word size). Only the `S#` constructor would be used (the library isn't
 compiled with `-funbox-strict-fields`). Maybe serialization would add an
 extra tag byte and there would be some additional unused branches in the
 code?

 Any suggestions for a good test case for the performance impact of this
 change?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14574#comment:7>
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