[GHC] #9533: Signed/unsigned integer difference between compiled and interpreted code

[GHC]

#9533: Signed/unsigned integer difference between compiled and interpreted code
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              Reporter:              |            Owner:
  MichaelBurge                       |           Status:  new
                  Type:  bug         |        Milestone:
              Priority:  high        |          Version:  7.8.3
             Component:  Compiler    |         Keywords:
            Resolution:              |     Architecture:  x86_64 (amd64)
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:  Incorrect   |  Related Tickets:
  result at runtime                  |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by rwbarton):

 Some more good stuff.

 {{{
 test = case 1 :: Int of
          18446744073709551617 -> "A" -- 2^64 + 1
          _  -> "B"
 main = putStrLn $ show test
 }}}
 prints "B". The `KnownBranch` optimization fires (even without `-O`) and
 thinks that 1 is not 18446744073709551617.

 I'm inclined to conclude that Core `Literal`s should always be wrapped to
 the range of integers that their type can represent. I assume that
 `HsLit`s should hold the actual integer in the source program, though, so
 we can display expressions as the user wrote them. Simon, any thoughts?

 Also, there is no warning about the out-of-range literal patterns in any
 of these programs. Perhaps that ought to be a separate feature request
 ticket.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9533#comment:3>
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