I am pleased to annouce that...

[Daniel]

Exactly zero of the Qt5/6 binding libraries work either with dub 
(if they have it on there).  I have tried them all and each gets 
errors, VisualD or not.

Therefore, it is smart / safe if a Qt5/6 developer stick with Qt 
VS tools (if you can get it to function) or simply Qt Creator 
itself.

This approach is vouched safe by the above.   So I will do my GUI 
in Qt Creator, hopefully not creating a memory leak (lots of 
QSharedPointers!), but my backend will of course be in D!

:D