[Issue 21035] wrong code when uses struct's methods of .init value

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21035

--- Comment #3 from Stefan Koch <uplink.coder at gmail.com> ---
What happens is that a `memcpy` fails which seems to be done executing `data[0
.. str.length] = str` 
why that happens is still under investigation

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