(I’ve updated this pattern, since a lot has changed since 2020. The recommendations here should be ready for the Rust 2024 edition, and are closer to correct in a post-pointer-provenance world.)

Here’s another useful Rust pattern. Like the Typestate Pattern before it, I wrote this because I haven’t seen the sort of obsessively nerdy writeup that I wanted to read. And, as with the Typestate Pattern, I didn’t invent this — I’m merely documenting and generalizing it.