Optional `ExpressibleByWrappedValue` superpowers

[hborla (Holly Borla)]

@tera

I see. Could we change this, e.g. rewiring the compiler logic to check for a special "init" or a "protocol", and make Optional to implement this init / adopt that protocol – it will not change optional behaviour but would allow other types to take advantage of this machinery.

You're asking for user-defined implicit conversions, which was most recently discussed here: Generalization of Implicit Conversions. This sort of feature would have serious implications on overload resolution performance, and I personally believe that this improvement:

@tera

var x: MyOptional<S> = S() // wanted
var x: MyOptional<S> = .some(S()) // have to do this instead

is not worth the overload resolution complexity and type-checker performance cost that comes with it.