os-rust/src/test/ui/object-safety/object-safety-generics.rs

// Check that we correctly prevent users from making trait objects
// from traits with generic methods, unless `where Self : Sized` is
// present.

trait Bar {
    fn bar<T>(&self, t: T);
}

trait Quux {
    fn bar<T>(&self, t: T)
        where Self : Sized;
}

fn make_bar<T:Bar>(t: &T) -> &dyn Bar {
        //~^ ERROR E0038
    t
}

fn make_bar_explicit<T:Bar>(t: &T) -> &dyn Bar {
    //~^ ERROR E0038
    t as &dyn Bar
}

fn make_quux<T:Quux>(t: &T) -> &dyn Quux {
    t
}

fn make_quux_explicit<T:Quux>(t: &T) -> &dyn Quux {
    t as &dyn Quux
}

fn main() {
}