[purplesyringa]

This feels like a misrepresentation of features that actually matter for memory safety. Automatically freeing locals and bounds checking is unquestionably good, but it's only the very beginning.

The real problems start when you need to manage memory lifetimes across the whole program, not locally. Can you return `UniquePtr` from a function? Can you store a copy of `SharedPtr` somewhere without accidentally forgetting to increment the refcount? Who is responsible for managing the lifetimes of elements in intrusive linked lists? How do you know whether a method consumes a pointer argument or stores a copy to it somewhere?

I appreciate trying to write safer software, but we've always told people `#define xfree(p) do { free(p); p = NULL; } while (0)` is a bad pattern, and this post really feels like more of the same thing.

[cryptonector]

> Can you return `UniquePtr` from a function?

Yes: you can return structures by value in C (and also pass them by value).

> Can you store a copy of `SharedPtr` somewhere without accidentally forgetting to increment the refcount?

No, this you can't do.

[teo_zero]

> we've always told people `#define xfree(p) do { free(p); p = NULL; } while (0)` is a bad pattern

Have we? Why?