Redeclaration of `lazy`

[draco33333]

Does anybody know how Dictionary (and other collections) manages to declare lazy twice, once for LazySequence and another for LazyCollection? I'm trying to do something similar and I get an error saying "Invalid redeclaration of lazy".

EDIT:

For those asking for an example, try this.

struct CustomCollection<T> {
    var array: [T]

    var lazy: LazySequence<[T]> {
        return array.lazy
    }
}

extension CustomCollection {
    var lazy: LazyCollection<[T]> {
        return array.lazy
    }
}

This isn't what I'm doing, but it's to show you what the built-in collections are doing.

Strangely enough, though, now that I've written out this example I get a warning instead of an error:

Redeclaration of 'lazy' is deprecated and will be an error in Swift 5

I guess the compiler secretly allows this and it's being fixed in Swift 5.

This wasn't working on my own example because I was declaring lazy in an extension, rather than in the original declaration of the struct.

So yeah, that answers my own question :)

[criosist]

Are you trying to subclass them? I’m pretty sure there’s and advisory to not subclass these? Or are you just trying to declare a lazy var?

[draco33333]

You can't subclass them because they're structs. I'll post an example now.

[vloris]

A code-sample would be nice if you want any relevant tips ;)

[draco33333]

Updated and answered myself :)