[Issue 21663] std.concurrency.receiveOnly doesn't work with tuples

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21663

--- Comment #2 from Paul Backus <snarwin+bugzilla at gmail.com> ---
Introduced in this PR:

https://github.com/dlang/phobos/pull/7661

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