[GHC] #12177: Relevant bindings includes shadowed bindings

[GHC]

#12177: Relevant bindings includes shadowed bindings
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           Reporter:  ezyang         |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
  (Type checker)                     |
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 {{{
 ezyang at sabre:~$ ghc-8.0 --interactive
 GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
 Prelude> \x -> \x -> _

 <interactive>:1:13: error:
     • Found hole: _ :: t2
       Where: ‘t2’ is a rigid type variable bound by
                the inferred type of it :: t -> t1 -> t2 at
 <interactive>:1:1
     • In the expression: _
       In the expression: \ x -> _
       In the expression: \ x -> \ x -> _
     • Relevant bindings include
         x :: t1 (bound at <interactive>:1:8)
         x :: t (bound at <interactive>:1:2)
         it :: t -> t1 -> t2 (bound at <interactive>:1:1)
 }}}

 GHC should not report bindings which are shadowed.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12177>
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