Wedson Almeida Filho is a Microsoft engineer who has been prolific in his contributions to the Rust for the Linux kernel code over the past several years. Wedson has worked on many Rust Linux kernel features and even did a experimental EXT2 file-system driver port to Rust. But he’s had enough and is now stepping away from the Rust for Linux efforts.
From Wedon’s post on the kernel mailing list:
I am retiring from the project. After almost 4 years, I find myself lacking the energy and enthusiasm I once had to respond to some of the nontechnical nonsense, so it’s best to leave it up to those who still have it in them.
…
I truly believe the future of kernels is with memory-safe languages. I am no visionary but if Linux doesn’t internalize this, I’m afraid some other kernel will do to it what it did to Unix.
Lastly, I’ll leave a small, 3min 30s, sample for context here: https://youtu.be/WiPp9YEBV0Q?t=1529 – and to reiterate, no one is trying force anyone else to learn Rust nor prevent refactorings of C code."
You’re going to need to cite that.
I’m not familiar with C23 or many of the compiler-specific extensions, but in all the previous versions I worked with, there is no type visibility other than “fully exposed” or opaque and dangerous (void*).
You could try wrapping your Foo in
typedef struct {
Foo validated
} ValidFoo;
But nothing stops someone from being an idiot about it and constructing it by hand:
ValidFoo trustMeBro;
trustMeBro.validated = someFoo;
otherFunction(trustMeBro);
Or even just casting it.
Foo* someFoo;
otherFunction((ValidFoo*) someFoo);
That’s not the point, though. The point is to use a nominal type that asserts an invariant and make it impossible to create an instance of said type which violates the invariant.
Both validation functions and refinement types put the onus on the caller to ensure they’re not passing invalid data around, but only refinement types can guarantee it. Humans are fallible, and it’s easy to accidentally forget to put a check_if_valid() function somewhere or assume that some function earlier in the call stack did it for you.
With smart constructors and refinement types, the developer literally can’t pass an unvalidated type downstream by accident.
