[GHC] #14052: Significant GHCi speed regression with :module and `let` in GHC 8.2.1

[GHC]

#14052: Significant GHCi speed regression with :module and `let` in GHC 8.2.1
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        Reporter:  RyanGlScott       |                Owner:  osa1
            Type:  bug               |               Status:  patch
        Priority:  high              |            Milestone:  8.4.2
       Component:  GHCi              |              Version:  8.2.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11547            |  Differential Rev(s):  Phab:D4478
       Wiki Page:                    |
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Comment (by mniip):

 I don't hold any strong opinion on how the shadowed identifiers should
 behave, but whichever way it is, I don't think an error similar to one in
 #11547 is appropriate. Perhaps it is best to hide the `Ghci#` modules in
 renamer too?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14052#comment:20>
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