1 files changed, 69 insertions, 0 deletions
diff --git a/tests/ui/binding/fn-arg-incomplete-pattern-drop-order.rs b/tests/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
new file mode 100644
index 00000000000..0450fe8abbd
--- /dev/null
+++ b/tests/ui/binding/fn-arg-incomplete-pattern-drop-order.rs
@@ -0,0 +1,69 @@
+// run-pass
+// needs-unwind
+// Check that partially moved from function parameters are dropped after the
+// named bindings that move from them.
+
+
+use std::{panic, cell::RefCell};
+
+struct LogDrop<'a>(i32, Context<'a>);
+
+#[derive(Copy, Clone)]
+struct Context<'a> {
+    panic_on: i32,
+    drops: &'a RefCell<Vec<i32>>,
+}
+
+impl<'a> Context<'a> {
+    fn record_drop(self, index: i32) {
+        self.drops.borrow_mut().push(index);
+        if index == self.panic_on {
+            panic!();
+        }
+    }
+}
+
+impl<'a> Drop for LogDrop<'a> {
+    fn drop(&mut self) {
+        self.1.record_drop(self.0);
+    }
+}
+
+fn bindings_in_params((_x, _): (LogDrop, LogDrop), (_, _y): (LogDrop, LogDrop)) {}
+fn bindings_with_let(a: (LogDrop, LogDrop), b: (LogDrop, LogDrop)) {
+    // Drop order in foo is the same as the following bindings.
+    // _temp2 is declared after _x to avoid a difference between `_: T` and
+    // `x: T` in function parameters.
+    let _temp1 = a;
+    let (_x, _) = _temp1;
+
+    let _temp2 = b;
+    let (_, _y) = _temp2;
+}
+
+fn test_drop_order(panic_on: i32, fun: fn((LogDrop, LogDrop), (LogDrop, LogDrop))) {
+    let context = Context {
+        panic_on,
+        drops: &RefCell::new(Vec::new()),
+    };
+    let one = LogDrop(1, context);
+    let two = LogDrop(2, context);
+    let three = LogDrop(3, context);
+    let four = LogDrop(4, context);
+
+    let res = panic::catch_unwind(panic::AssertUnwindSafe(|| {
+        fun((three, four), (two, one));
+    }));
+    if panic_on == 0 {
+        assert!(res.is_ok(), "should not have panicked");
+    } else {
+        assert!(res.is_err(), "should have panicked");
+    }
+    assert_eq!(*context.drops.borrow(), [1, 2, 3, 4], "incorrect drop order");
+}
+
+fn main() {
+    (0..=4).for_each(|i| test_drop_order(i, bindings_in_params));
+    (0..=4).for_each(|i| test_drop_order(i, bindings_with_let));
+    (0..=4).for_each(|i| test_drop_order(i, |(_x, _), (_, _y)| {}));
+}