Implements “Stacked Borrows”. See https://github.com/rust-lang/unsafe-code-guidelines/blob/master/wip/stacked-borrows.md for further information.
Tracking pointer provenance
Per-call-stack-frame data for borrow tracking
Extra global state, available to the memory access hooks.
Indicates which kind of access is being performed.
Extra per-allocation data for borrow tracking
Which borrow tracking method to use
The flavor of the protector.
Policy on whether to recurse into fields to retag