[MacPorts] #60765: xeus, nlohmann-json: error: an attribute list cannot appear here

[MacPorts]

#60765: xeus, nlohmann-json: error: an attribute list cannot appear here
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  Reporter:  ryandesign           |      Owner:  Schamschula
      Type:  defect               |     Status:  assigned
  Priority:  Normal               |  Milestone:
 Component:  ports                |    Version:  2.6.2
Resolution:                       |   Keywords:
      Port:  xeus, nlohmann-json  |
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Comment (by ryandesign):

 Yes, Yosemite.

 You can see from the [https://ports.macports.org/port/xeus/summary xeus
 port page] that it built fine on 10.7-10.9 using newer MacPorts clang.

 It failed on 10.10 using Apple clang 7 and failed on 10.11 using Apple
 clang 8.

 It built fine on 10.13 using Apple clang 9.

 10.12 is busy and hasn't built this yet.

 But a good guess might be to blacklist {clang < 900}, if we want to solve
 it by blacklisting.

 Although xeus is the port that failed to build, the file generating the
 error is from nlohmann-json. Maybe that indicates that the fix should be
 in nlohmann-json.

 Maybe the problem should be reported to the upstream developers so that
 they have a chance to weigh in on a fix.

-- 
Ticket URL: <https://trac.macports.org/ticket/60765#comment:2>
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