shorter-bounds

Provides a macro to easily define a trait alias, implemented automatically for all types that implement the super traits. It supports both supertrait bounds (trait Foo : Bounds) and type parameters bounds (trait Foo<T: (Bounds)>). The latter requires parenthesis around the bounds to easility parse them and support any valid Rust bound syntax.

Since Rust 1.79, you can add bounds to traits associated types, which will also imply that bound when the trait alias is used (contrary to using a where clause). This allows to define powerful trait aliases that avoids repeating many <Foo as Bar>::Baz : Traits.

Syntax

shorter_bounds::alias!(
    pub // Optional
    trait
    MyTraitAlias
    // Can be followed by type parameters
    <
        Foo,
        // Type paramter can have bounds, but they must be wrapped inside parenthesis
        Bar: (Clone + Iterator<Item: Clone>),
    >
    :
    // List of traits being aliased
    Clone +
        Iterator<Item = (Foo, Bar)>
);

Exemple

shorter_bounds::alias!(pub trait IterableOfClonable: Iterator<Item: Clone>);
fn exemple(iter: impl IterableOfClonable) {
    for x in iter {
        let _ = x.clone();
    }
}
exemple([42, 63].into_iter());