[GHC] #10071: Implement deprecation-warnings for class-methods to non-method transitions

[GHC]

#10071: Implement deprecation-warnings for class-methods to non-method transitions
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        Reporter:  hvr               |                   Owner:
            Type:  feature request   |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Compiler          |                 Version:  7.8.4
      Resolution:                    |                Keywords:  AMP
Operating System:  Unknown/Multiple  |  MonadFail
 Type of failure:  None/Unknown      |            Architecture:
      Blocked By:                    |  Unknown/Multiple
 Related Tickets:  #8004, #4384      |               Test Case:
                                     |                Blocking:
                                     |  Differential Revisions:
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Comment (by simonpj):

 I have attempted a precise specification, in
 [wiki:Design/MethodDeprecations].  See if you agree with it.

 What about this?  (Using the main example in
 [wiki:Design/MethodDeprecations]
 {{{
 module M where
 import X
 import M1 ( C(..) )
 x = bar ()
 }}}
 Do we get a warning here?  You might say that since `X` doesn't export
 `bar` (which is not obvious) that the only way it can be in scope is via
 `C(..)`.

 I say yes, and I have articulated that in the wiki page.  There is a
 design alternative described there too; I'm not sure what you want.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10071#comment:10>
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