[GHC] #12411: GHC panic on TypeApplications + TemplateHaskell

[GHC]

#12411: GHC panic on TypeApplications + TemplateHaskell
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           Reporter:  Iceland_jack   |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Unknown/Multiple
  TypeApplications, TemplateHaskell  |
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 This fails

 {{{
 $ ghci -XTemplateHaskell -ignore-dot-ghci
 GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
 Prelude> import Control.Lens
 Prelude Control.Lens> data A = B { _int :: Int }
 Prelude Control.Lens> pure @Q []; makeLenses ''A
 ghc: panic! (the 'impossible' happened)
 (GHC version 8.0.1 for x86_64-unknown-linux):
 tcMonoExpr _

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 Prelude Control.Lens>
 }}}

 sorry, don't have time for more detail

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12411>
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