[mirekrusin]

Interesting.

So you're saying that Rust, at the moment, in theory, can be used in any place where C is required? Ie. writing kext on macOS, loadable kernel module on Linux or things like extension for SQLite are all possible?

In that case I wonder if there are any theoretical blockers for things like (using no_std and) mapping internally used C structures (let's say BSD kernel's rbtree) into typed, first-class Rust citizens - to avoid std overhead and reuse what's already available? In other words - is there anything there in C macros that can't effectively be expressed in Rust for example?

[steveklabnik]

That's correct.

There are no theoretical blockers; tooling could make it a lot easier though. I was hand-porting chunks of the Ruby interpreter, which uses C macros extensively, and it's doable, but not fun.