rust/src/test/ui/traits/bound/not-on-bare-trait.rs

trait Foo {
    fn dummy(&self) {}
}

// This should emit the less confusing error, not the more confusing one.

fn foo(_x: Foo + Send) {
    //~^ ERROR the size for values of type
    //~| WARN trait objects without an explicit `dyn` are deprecated
    //~| WARN this is valid in the current edition
}

fn main() {}