rust/src/test/ui/object-lifetime/object-lifetime-default-mybox.rs

// ignore-compare-mode-nll
// revisions: base nll
// [nll]compile-flags: -Zborrowck=mir

// Test a "pass-through" object-lifetime-default that produces errors.

#![allow(dead_code)]

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

struct MyBox<T:?Sized> {
    r: Box<T>
}

fn deref<T>(ss: &T) -> T {
    // produces the type of a deref without worrying about whether a
    // move out would actually be legal
    loop { }
}

fn load0(ss: &MyBox<dyn SomeTrait>) -> MyBox<dyn SomeTrait> {
    deref(ss)
}

fn load1<'a,'b>(a: &'a MyBox<dyn SomeTrait>,
                b: &'b MyBox<dyn SomeTrait>)
                -> &'b MyBox<dyn SomeTrait>
{
    a
    //[base]~^ ERROR lifetime mismatch
    //[nll]~^^ ERROR lifetime may not live long enough
}

fn load2<'a>(ss: &MyBox<dyn SomeTrait + 'a>) -> MyBox<dyn SomeTrait + 'a> {
    load0(ss)
    //[base]~^ ERROR mismatched types
    //[nll]~^^ ERROR borrowed data escapes outside of function
}

fn main() {
}