[GHC] #10246: Literal Pattern match loses order

[GHC]

#10246: Literal Pattern match loses order
-------------------------------------+-------------------------------------
        Reporter:  nomeata           |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
Changes (by nomeata):

 * cc: rwbarton, simonmar (added)


Comment:

 Currently, the above code will produce
 {{{
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 7.11.20150403 for x86_64-unknown-linux):
         ASSERT failed!
   file compiler/basicTypes/Literal.hs line 220 18446744073709551616
 }}}

 Maybe that is a hint as to where this needs to be fixed? Maybe
 {{{
 mkMachInt :: DynFlags -> Integer -> Literal
 mkMachInt dflags x   = ASSERT2( inIntRange dflags x,  integer x )
                        MachInt x
 }}}
 is where the clamping to the range of the machine integers should happen?
 Can we always deduce that from the `dflags`?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10246#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler