[GHC] #9046: Panic in GHCi when using :print

[GHC]

#9046: Panic in GHCi when using :print
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              Reporter:  quchen      |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  7.8.4
             Component:  GHCi        |          Version:  7.8.2
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  GHCi crash  |       Blocked By:
             Test Case:              |  Related Tickets:
  tests/ghci.debugger/scripts/print036|
              Blocking:              |
Differential Revisions:              |
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Comment (by francesquini):

 Same problem, different steps:


 {{{
 GHCi, version 7.8.3: http://www.haskell.org/ghc/  :? for help
 Loading package ghc-prim ... linking ... done.
 Loading package integer-gmp ... linking ... done.
 Loading package base ... linking ... done.
 Prelude> let x = 3 + 4
 Prelude> :print x
 x = (_t1::Num a => a)
 Prelude> :force x
 x = _
 Prelude> print _t1
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.8.3 for x86_64-unknown-linux):
     tcTyVarDetails a{tv atm} [tv]
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9046#comment:11>
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