1 // Set the length of the vec when the `SetLenOnDrop` value goes out of scope.
3 // The idea is: The length field in SetLenOnDrop is a local variable
4 // that the optimizer will see does not alias with any stores through the Vec's data
5 // pointer. This is a workaround for alias analysis issue #32155
6 pub(super) struct SetLenOnDrop<'a> {
11 impl<'a> SetLenOnDrop<'a> {
13 pub(super) fn new(len: &'a mut usize) -> Self {
14 SetLenOnDrop { local_len: *len, len }
18 pub(super) fn increment_len(&mut self, increment: usize) {
19 self.local_len += increment;
23 impl Drop for SetLenOnDrop<'_> {
26 *self.len = self.local_len;