Skip to main content

## SHADOWING_SUPERTRAIT_ITEMS

# Static SHADOWING_SUPERTRAIT_ITEMS

Source

    pub static SHADOWING_SUPERTRAIT_ITEMS: &'static Lint

Expand description

The `shadowing_supertrait_items` lint detects when the definition of an item that is provided by both a subtrait and supertrait is shadowed, preferring the subtrait.

#### §Example

ⓘ

    #![feature(supertrait_item_shadowing)]
    #![deny(shadowing_supertrait_items)]

    trait Upstream {
        fn hello(&self) {}
    }
    impl<T> Upstream for T {}

    trait Downstream: Upstream {
        fn hello(&self) {}
    }
    impl<T> Downstream for T {}

{{produces}}

#### §Explanation

RFC 3624 specified a heuristic in which a supertrait item would be shadowed by a subtrait item when ambiguity occurs during item selection. In order to mitigate side-effects of this happening silently, this lint detects these cases when users want to deny them or fix their trait definitions.