Why can't `Self` be used to refer to an enum's variant in a method body?

Question

This question is now obsolete because this feature has been implemented. Related answer.

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The following Rust code fails to compile:

enum Foo {
    Bar,
}

impl Foo {
    fn f() -> Self {
        Self::Bar
    }
}

The error message confuses me:

error[E0599]: no associated item named `Bar` found for type `Foo` in the current scope
 --> src/main.rs:7:9
  |
7 |         Self::Bar
  |         ^^^^^^^^^

The problem can be fixed by using Foo instead of Self, but this strikes me as strange since Self is supposed to refer to the type that is being implemented (ignoring traits), which in this case is Foo.

enum Foo {
    Bar,
}

impl Foo {
    fn f() -> Self {
        Foo::Bar
    }
}

Why can't Self be used in this situation? Where exactly can Self be used^*? Is there anything else I can use to avoid repeating the type name in the method body?

^{* I'm ignoring usage in traits, where Self refers to whatever type implements the trait.}

Answer 1

This is now possible as of version 1.37.