That sounds like the "generation" tag in Vale's generational references [0] or like how memory tagging works on ARM CPUs [1].

I love the approach, it's a way to get a lot more memory safety while not giving up a program's flexibility, especially in C's case.

Some languages are opting to disallow pointer arithmetic and conversion between integers and pointers. We'll see how it works out!

[0] https://verdagon.dev/blog/generational-references

[1] https://developer.arm.com/-/media/Arm%20Developer%20Communit...