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# Error code E0714

A `#[marker]` trait contained an associated item.

Erroneous code example:

    #![feature(marker_trait_attr)]
    #![feature(associated_type_defaults)]

    #[marker]
    trait MarkerConst {
        const N: usize; // error!
    }

    fn main() {}

The items of marker traits cannot be overridden, so there's no need to have them when they cannot be changed per-type anyway. If you wanted them for ergonomic reasons, consider making an extension trait instead.