[GHC] #11444: 8.0 rc1 panics in applyTypeToArgs

[GHC]

#11444: 8.0 rc1 panics in applyTypeToArgs
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        Reporter:  osa1              |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1-rc1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13027            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dfeuer):

 Sorry; that last comment was unclear. If we have

 {{{#!hs
 case x of x' { _ ->
 case y of y' { _ ->
 case reallyUnsafePtrEquality# x' y' of {....}}}
 }}}

 and we substitute as above,

 {{{#!hs
 case x of x' { _ ->
 case y of y' { _ ->
 case reallyUnsafePtrEquality# x y of {....}}}
 }}}

 then wouldn't floating out lead to this?

 {{{#!hs
 let wrong = reallyUnsafePtrEquality# x y in {
 case x of x' { _ ->
 case y of y' { _ ->
 case wrong of { ... }}}}
 }}}

 Now the pointer equality test could be performed ''before'' the reductions
 that would make it much more precise!

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11444#comment:14>
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