[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:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.4.1
       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:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"6257fb528c1c92fbe3bd66441bfba00f632d1b50/ghc" 6257fb5/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="6257fb528c1c92fbe3bd66441bfba00f632d1b50"
 Comments about GlobalRdrEnv shadowing

 Provoked by Trac #14052
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14052#comment:12>
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