[GHC] #11451: Inconsistent warnings for unused binders in type and instance declarations

[GHC]

#11451: Inconsistent warnings for unused binders in type and instance declarations
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        Reporter:  simonpj           |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1825
       Wiki Page:                    |
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Comment (by RyanGlScott):

 Simon, I believe we will have precisely what you described with
 Phab:D1825. `-Wname-shadowing` controls unused `forall`-ed type variables,
 and `Wtype-variables` controls unused type patterns separately. You can
 enable different combinations of them to achieve A, B, and C.

 The only remaining question is if we want a single flag that implies C (my
 previous name suggestion was `-pedantic`). This would be pretty easy to
 implement if we wanted it, since it would just enable a superset of the
 flags implied by `-Wall`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11451#comment:28>
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