[GHC] #15211: exprFreeVars does not include type variables

[GHC]

#15211: exprFreeVars does not include type variables
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           Reporter:  goldfire       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           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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 The `exprFreeVars` function returns the free variables of an expression.
 However, this function doesn't include the type variables free in the free
 term variables. This might be OK for some uses, but it seems ''not'' OK if
 we use the result of `exprFreeVars` in an `InScopeSet`, which is done in
 many places.

 I don't have a program that exhibits misbehavior, but I feel fairly sure
 that we have a problem here.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15211>
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