Auto merge of #37605 - dsprenkels:arc-max-refcount, r=alexcrichton

Fix Arc::clone()'s MAX_REFCOUNT check (off-by-one)

Before, the strong count of an `Arc` could be set to
`MAX_REFCOUNT + 1`, because when this happened, `old_size` would
be exactly `MAX_REFCOUNT`. `Arc::clone()` would not abort.

This commit changes the check in `Arc::clone()` to also abort if
the old value is equal to `MAX_REFCOUNT`, because then the new
value will be equal to `MAX_REFCOUNT + 1`.

A test would require allocating memory for `isize::MAX` pointers.
This would probably crash any machine, so no test is submitted
with this commit.

0 files changed, 0 insertions, 0 deletions