[Issue 22359] joiner over an empty forward range object liable to segfault

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=22359

--- Comment #1 from Adam D. Ruppe <destructionator at gmail.com> ---
There's also a

          static if (isBidirectional && hasNested!Result)
                _currentBack = typeof(_currentBack).init;


Same problem.

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