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Test drop order for (destructuring) assignments #79177

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44 changes: 44 additions & 0 deletions src/test/ui/destructuring-assignment/drop-order.rs
Original file line number Diff line number Diff line change
@@ -0,0 +1,44 @@
// run-pass

//! Test that let bindings and destructuring assignments have consistent drop orders

#![feature(destructuring_assignment)]
#![allow(unused_variables, unused_assignments)]

use std::cell::RefCell;

thread_local! {
static DROP_ORDER: RefCell<Vec<usize>> = RefCell::new(Vec::new());
}

struct DropRecorder(usize);
impl Drop for DropRecorder {
fn drop(&mut self) {
DROP_ORDER.with(|d| d.borrow_mut().push(self.0));
}
}

fn main() {
let expected_drop_order = vec![1, 4, 5, 3, 2];
// Check the drop order for let bindings:
{
let _ = DropRecorder(1);
let _val = DropRecorder(2);
let (x, _) = (DropRecorder(3), DropRecorder(4));
drop(DropRecorder(5));
}
DROP_ORDER.with(|d| {
assert_eq!(&*d.borrow(), &expected_drop_order);
d.borrow_mut().clear();
});
// Check that the drop order for destructuring assignment is the same:
{
let _val;
let x;
_ = DropRecorder(1);
_val = DropRecorder(2);
(x, _) = (DropRecorder(3), DropRecorder(4));
drop(DropRecorder(5));
}
DROP_ORDER.with(|d| assert_eq!(&*d.borrow(), &expected_drop_order));
}