Feature Request: Derive Default from Enum Variant

[mitsuhiko]

A relatively common situation for me is an enum that has one variant that should become the default. It would be nice if one could select the variant that should become the default and be able to automatically derive a Default for it:

enum Variant {
    Undefined, // hover and "derive Default for this variant"
    Minor,
    Major,
}

Would then produce this:

impl Default for Variant {
    fn default() -> Variant {
        Variant::Undefined
    }
}

[bnjjj]

Will implement this ! I also have this kind of issue