[Issue 18538] ubyte[] can append to string

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18538

--- Comment #1 from FeepingCreature <default_357-line at yahoo.de> ---
Bonus round!

Works: s ~= ub;

Does not work: s = s ~ ub;

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