Slices contain `addr`s so the same rules apply to them. They can't be stored
in structs and so on. But they may be an efficient temporary while parsing.
Streams are currently a second generic type after arrays, and gradually
strengthening the case to just bite the bullet and support first-class
generics in Mu.
- allocate var
- populate var, n
Both rely on the type of `var` to compute the size of the allocation. No
need to repeat the name of the type like in C, C++ or Java.
Kartik Agaram