[GHC] #12711: GHC Internal error, unboxed sums

[GHC]

#12711: GHC Internal error, unboxed sums
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           Reporter:  Iceland_jack   |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:  UnboxedSums    |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 {{{
 $ ./ghc-stage2 -ignore-dot-ghci --interactive
 GHCi, version 8.1.20160930: http://www.haskell.org/ghc/  :? for help
 Prelude> :set -XUnboxedSums
 Prelude> :kind (# _ | _ #)

 <interactive>:1:4: error:
     • GHC internal error: ‘_’ is not in scope during type checking, but it
 passed the renamer
       tcl_env of environment: []
     • In the type ‘(# _ | _ #)’
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12711>
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