src/test/ui/error-codes/E0277-2.rs

struct Foo {
    bar: Bar
}

struct Bar {
    baz: Baz
}

struct Baz {
    x: *const u8
}

fn is_send<T: Send>() { }

fn main() {
    is_send::<Foo>();
    //~^ ERROR `*const u8` cannot be sent between threads safely
}