Support nested enum?

[nine-point-eight-p]

Hi! I've just found this crate and it helps me a lot dealing with the common fields in enum. Sadly it's doesn't work because I have a nested enum where the leaf variants share a same attribute. Is it possible to support something like this?

enum Foo {
    A { key: String },
    B(Bar),
}

enum Bar {
    C { key: String },
    D { key: String },
}