ok at last i think i am getting somewhere useful: i have used abstract interpretation at the type level to persuade rust to automatically track which parts of a complex number are known to be zero at compile time, and can therefore be eliminated at run time

Impressive.

it has taken me AGES to work out how to do this, sodding difficult :-)

I trust any experience you've had with `rustup` has been okay though? </cheeky-segue>

It has worked ok so far :-)