[Issue 18538] ubyte[] can append to string

[d-bugmail at puremagic.com]

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

ag0aep6g at gmail.com changed:

           What    |Removed                     |Added
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           Keywords|                            |accepts-invalid
                 CC|                            |ag0aep6g at gmail.com

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