[GHC] #7414: plugins always trigger recompilation

[GHC]

#7414: plugins always trigger recompilation
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        Reporter:  jwlato            |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.6.1
      Resolution:                    |             Keywords:  plugin,
                                     |  recompilation
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by ezyang):

 Plugin interface hash is insufficient, since you want to recompile if the
 plugin implementation changes (even if its unfoldings do not.)  It's
 almost as if you just want the file modification time...

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7414#comment:6>
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