[GHC] #15721: Command `:show bindings` throws exception for bindings without `let`

[GHC]

#15721: Command `:show bindings` throws exception for bindings without `let`
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        Reporter:  sighingnow        |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  GHCi              |              Version:  8.6.1
      Resolution:                    |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHCi crash        |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by AndreasK):

 Can't reproduce this on windows either. Tried 8.6.1 and master:

 {{{
 PS C:\Users\Andi> stack ghci --compiler=ghc-8.6

 ...

 Configuring GHCi with the following packages:
 GHCi, version 8.6.1: http://www.haskell.org/ghc/  :? for help
 Loaded GHCi configuration from C:\Users\Andi\AppData\Local\Temp\haskell-
 stack-ghci\2a3bbd58\ghci-script
 Prelude> x = 'a'
 Prelude> :show bindings
 $trModule :: GHC.Types.Module = _
 x :: Char = _
 Prelude>
 }}}

 What OS have you been using? And what commit on master?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15721#comment:2>
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