[GHC] #15562: `-XStrict -XNoStrict` is not neutral

[GHC]

#15562: `-XStrict -XNoStrict` is not neutral
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        Reporter:  hvr               |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.3
      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 hvr):

 Replying to [comment:4 goldfire]:
 > My vote would be simply not to make any guarantees of this sort. It's
 not hard for a tool to consult `DynFlags.impliedXFlags` and figure out
 what reorderings are OK.

 While I agree now with that it's hopeless to give any guarantees; I
 disagree that consulting `DynFlags.impliedXFlags` is "not hard" for tools
 -- tools most often avoid to link against `lib:ghc` so they wouldn't have
 access to it; instead they tend to query e.g. `ghc --supported-languages`
 which unfortunately does not expose the relationships between those flags.

 It would be very useful for tooling if `ghc`'s CLI had some flag to dump
 an extended version of `--supported-languages` that's easy to parse

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15562#comment:5>
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