[Issue 20305] String mixins fail for structs with 'alias this'

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20305

Iain Buclaw <ibuclaw at gdcproject.org> changed:

           What    |Removed                     |Added
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           Priority|P1                          |P4

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