New function `convert!`?

proposal

#1

I just played a little around with push and pop and push! and pop! in the new RC for Julia 1.0. Is there a reasion, why convert! is not implemented?


#3

What would it do? The result is of a different type than the input, so cannot be written to the same memory spot.


#4

I have been moving in the direction of overloading copyto! for this kind of thing.