Re: [GHC] #16163: Don’t throw an error (by default) for use of DEPRECATED symbols under -Werror

[GHC]

#16163: Don’t throw an error (by default) for use of DEPRECATED symbols under
-Werror
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        Reporter:  m-renaud          |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by m-renaud):

 Thank you for the feedback! I completely agree with the concerns raised
 here, I just posted a comment to the Reddit thread[1] that clarifies how
 this proposal fits into to the issue I'm trying to address (which I should
 have made more/clear prominent in this proposal).

 In summary (see linked thread for more details), the main problem I'm
 trying to solve is the lack of policy/clarity around deprecating APIs,
 specifically that anything that causes a breakage under `-Werror` requires
 a major version bump.

 This can either be addressed by a policy change, or a code/behaviour
 change (this proposal). Having both in hand you can compare the pros/cons
 of each instead of talking about "some proposal that could exist" in the
 abstract. I personally would prefer a policy change, in which case this
 proposal would become obsolete.

 There's also the fact that I should have broken this into two: A.
 differentiate between `DEPRECATED` and `WARNING` at the flag level
 (currently they're conflated). And B. which changes the behaviour of
 `-Werror`. I think (A) is non-controversial (and should probably be done
 anyways?), (B) is the controversial part since its a change in behaviour.

 Let me know your thoughts, as well as if you would be in favour of the
 policy change instead of this proposal. Thanks!

 [1]
 https://www.reddit.com/r/haskell/comments/aelbv7/rfc_ghc_proposal_dont_throw_an_error_by_default/edrjt5n

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16163#comment:5>
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