[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 goldfire):

 comment:3 requires that enabling one extension never disables another.
 However, this is not true! `RebindableSyntax` implies `NoImplicitPrelude`.
 Accordingly, `ImplicitPrelude` and `RebindableSyntax` do not commute. And,
 earlier this summer, `TypeOperators` implied `NoStarIsType`. This feature
 was removed because it made for a bad migration story, not because it
 violated this principle.

 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.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15562#comment:4>
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