Moving out of boxed structs by destructuring no longer works

[apoelstra]

In 1.3.0,

struct PatriciaTree {
    data: Box<u8>,
    child_l: Box<u8>,
}

impl PatriciaTree {
    fn delete(&mut self) {
        let child = Box::new(PatriciaTree { data: Box::new(5), child_l: Box::new(5) });
        let PatriciaTree { data, child_l } = *child;
    }
}

fn main() {}

fails with

break3.rs:10:34: 10:41 error: use of moved value: `child` [E0382]
break3.rs:10         let PatriciaTree { data, child_l } = *child;
                                              ^~~~~~~
break3.rs:10:28: 10:32 note: `child` moved here (through moving `child.data`) because it has type `Box<u8>`, which is moved by default
break3.rs:10         let PatriciaTree { data, child_l } = *child;
                                        ^~~~
break3.rs:10:28: 10:32 help: if you would like to borrow the value instead, use a `ref` binding as shown:
break3.rs:           let PatriciaTree { ref data, child_l } = *child;
error: aborting due to previous error

This is a common pattern for moving all the fields at once out of a struct (since moving them one by one could introduce memory unsafety).

Edit: I posted the wrong error message in the first version of this bug; fixed now.

[apoelstra]

Removing the box by adding the line let child = *child before destructuring is a workaround.

[alexcrichton]

Duplicate of #16223, but thanks for the report!