ab18da61f4
Verify copies of mutable pointers in 2 stages in ReferencePropagation Fixes #111422 In the first stage, we mark the copies as reborrows, to be checked later. In the second stage, we walk the reborrow chains to verify that all stages are fully replacable. The replacement itself mirrors the check, and iterates through the reborrow chain. r? ``````@RalfJung`````` cc ``````@JakobDegen``````