Ergonomics of wrapping operations

[wackywendell]

@nikomatsakis

This could be tricky. There are places that we currently rely on numeric literals being known to be some sort of scalar type -- even if we don't know which one. Some sort of suffix (2w) would work fine. We might also be able to lift those restrictions from type inference; I haven't investigated deeply in a while.

Mm, that's unfortunate. I'm not too familiar with the internals - what do you mean by "some sort of scalar type"? Would it be possible to make Wrapping<T> a "scalar type", for "scalar types" T?