Fix Ptr inconsistency in {Rc,Arc} #138303
Open
+44
−20
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PR Description
This pr aims to address the problem discussed on zulip.
Problem Clarification
As this post presents, the
{Rc, Arc}::{in/de-crement_strong_count_/in}
do not limit the layout of the memory thatptr
points to, while internallyRc::from_raw_in
is called directly.UB doesn't just appear when the strong count is decremented to zero. Miri also detects the UB of
out-of-bounds pointer use
when increment strong count is called on a pointer with an incorrect layout(shown as below).Miri output: