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This post is auto-generated from RSS feed The Rust Programming Language Forum - Latest topics. Source: Where does the document say that the satisfaction relationship is transitive between two trait bounds?

Consider this example:

fn call<'a:'static, F>(f: F)
where
    F: Fn(&'a str),
{
    call2(f);
}

fn call2<F>(_: F)
where
    F: Fn(&'static str),
{
}

fn main() {}

This code can be compiled. The result seems to imply that if F satisfies Fn(&'a T), it will also satisfy Fn(&'b T) if 'a:'b. This seems to not only apply to Fn Trait but also for customized traits, for example:

trait MyTrait<'a> {}

impl<'a> MyTrait<'a> for i32 {}

fn call<'a:'static, F>(f: F)
where
    F: MyTrait<'a>,
{
    call2(f);
}

fn call2<F>(_: F)
where
    F: MyTrait<'static>,
{
}

fn main() {}

I don't find any document that tells this point.

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