https://issues.dlang.org/show_bug.cgi?id=20529

          Issue ID: 20529
           Summary: Cyclic dependency caused by import of core.time
           Product: D
           Version: D2
          Hardware: All
                OS: All
            Status: NEW
          Severity: normal
          Priority: P1
         Component: druntime
          Assignee: nobody@puremagic.com
          Reporter: bugzilla@d-ecke.de

Created attachment 1773
  --> https://issues.dlang.org/attachment.cgi?id=1773&action=edit
Small example extracted from Phobos with dustmite

Executing run.sh in the attached example yields:

object.Error@src/rt/minfo.d(371): Cyclic dependency between module std.traits
and std.concurrency
std.traits* ->
std.range ->
std.datetime ->
std.datetime.timezone ->
std.concurrency* ->
std.traits*

When you remove the import of core.time in std.datetime this dependency vanishes.

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