[GHC] #13215: Panic: push_bang_into_newtype_arg

[GHC]

#13215: Panic: push_bang_into_newtype_arg
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        Reporter:  nad               |                Owner:  mpickering
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 What is the fix?  Generally we are transforming
 {{{
 f !(F n) = ...
 }}}
 into
 {{{
 f (F !n) = ...
 }}}
 What if it's this?
 {{{
 f !(F {}) = ...
 }}}
 We do still need to be strict.  So perhaps we transform to
 {{{
 f (F !_) = ...
 }}}
 Looks ok to me (with a Note). Could you execute on that?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13215#comment:4>
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