Oh! There was a directly related talk at RustWeek.
At 33:44, someone brings up GhostCell; earlier, at 28:05, @aapoalas.trynova.dev talks about a similar approach in gc-arena, and the speaker also mentions Haskell's ST monad, which expresses the same idea.
See also: the generativity crate.
Thanks to the GhostCell paper for teaching me branded types in Rust via invariant lifetimes. This has been *awesome* for eliminating pretty much all bounds and length checks in my indexing-heavy code (and enforcing more subtle invariants).
