[GHC] #12967: GHC 8.0.1 Panic for current Aeson 1.0.2.1

[GHC]

#12967: GHC 8.0.1 Panic for current Aeson 1.0.2.1
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        Reporter:  bitemyapp         |                Owner:  (none)
            Type:  bug               |               Status:  infoneeded
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      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 mpickering):

 I think Ryan is right that the `INLINE` pragmas in
 `Data.Aeson.Encoding.Builder` are too aggressive.

 In this example, `utcTime` contains a call to `timeOfDay` which is a huge
 function marked with an `INLINE` pragma. This causes the unoptimised
 unfolding for `timeOfDay` to be inlined into the unfolding for `utcTime`
 which is then inlined 12 times in the example Ryan posted. So there is a
 lot of duplicated work because of how the inline pragmas cause unfoldings
 not to be optimised.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12967#comment:4>
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