use std::marker::PhantomData;

struct Bar<'a, S> {
    phantom: PhantomData<S>,
    data: &'a mut Vec<u8>,
}

impl<'a, S> Bar<'a, S>
where
    S: Foo<'a>,
{
    fn new(data: &'a mut Vec<u8>) -> Self {
        Bar {
            phantom: PhantomData,
            data,
        }
    }
    fn foo_method(&mut self) {
        S::new().do_stuff(&mut self.data);
    }
}

trait Foo<'a> {
    fn new() -> Self;
    fn do_stuff(&self, _name: &'a mut Vec<u8>);
}

struct FooA {}

impl<'a> Foo<'a> for FooA {
    fn new() -> FooA {
        FooA {}
    }
    fn do_stuff(&self, _name: &'a mut Vec<u8>) {}
}

fn main() {
    let mut v = Vec::<u8>::new();
    Bar::<FooA>::new(&mut v).foo_method();
}