[GHC] #15007: Don't keep shadowed variables in ghci, both renamer and type checker

[GHC]

#15007: Don't keep shadowed variables in ghci, both renamer and type checker
-------------------------------------+-------------------------------------
        Reporter:  sighingnow        |                Owner:  sighingnow
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  GHCi              |              Version:  8.5
      Resolution:                    |             Keywords:  TypedHoles
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  error/warning at compile-time      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11547 #14052     |  Differential Rev(s):
  #15202                             |
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * related:  #11547 #14052 => #11547 #14052 #15202


Comment:

 Another example from #15202:

 > Run `ghc --interactive`, and at the prompt type
 >
 > {{{#!hs
 > default ()
 > fish :: Eq a => a; fish = undefined
 > foo :: String; foo = show _
 > }}}
 >
 > The following error appears:
 >
 > {{{
 > <interactive>:1:1: error:
 >     GHC internal error: ‘Ghci1.$trModule’ is not in scope during type
 checking, but it passed the renamer
 >     tcl_env of environment: [r2CZ :-> Identifier[foo::String,
 TopLevelLet]]
 > }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15007#comment:4>
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