lang-team VS miri

The Rust team did a deep dive on the bug in 2020, which has some more details that might be helpful to understanding what's going on: https://github.com/rust-lang/lang-team/blob/master/design-me....

I haven't been following this closely, so I looked it up and it looks like that's not going to happen for the foreseeable future unfortunately:

https://github.com/rust-lang/lang-team/issues/122

Kind of a shame, but wrapper types work well enough that I understand. It does look like if there was someone with enough resources to make it happen that they'd be receptive to it.

Did you read the link the original comment posted? I think that explains the idea rather well https://github.com/rust-lang/lang-team/issues/122

A quick search pulled up this as a likely candidate for most recent discussion of it but it goes back at least to 2016 with this RFC.

There have been at least one proposal and RFC in the past that seem to be deferred or closed due to bandwidth issues.

That's what Rust does, and it's considered a problem (that the devs are regrettably unable to reasonably solve) rather than a good thing.

Lang had some conversations about this: https://github.com/rust-lang/lang-team/issues/139

The design of Rust panics unconditionally aborts the program if you panic while unwinding, and some people even want to abort if you panic in Drop.

> Better interoperability

AFAIK, the examples you give all target a basic C ABI [0] or can be made to target the same ABI. In Rust, it means targeting wasm32-unknown-emscripten

The Rust team is also working on a "WASM ABI"[1] which would be useful in taking advantage of stuff like multi-value returns, and other compilers could just choose to target that. More likely, the C ABI on WASM will be updated to account for missing features, and that'll be the standard for interoperability in the WASM ecosystem.

[0]: https://github.com/WebAssembly/tool-conventions/blob/main/Ba...

[1]: https://github.com/rust-lang/lang-team/blob/master/design-me...

Miri [0] is an interpreter for the mid-level intermediate representation (MIR) generated by the Rust compiler. MIR is input for more processing steps of the compiler. However miri also runs MIR directly. This means miri is a VM. Of course it's not a bytecode VM, because MIR is not a bytecode AFAIK. I still think that miri is a interesting example.

And why does miri exist?

It is a lot slower. However it can check for some undefined behavior.

[0]: https://github.com/rust-lang/miri

Provenance is a dynamic property of pointer values. The actual underlying rules that a program must follow, even when using raw pointers and `unsafe`, are written in terms of provenance. Miri (https://github.com/rust-lang/miri) represents provenance as an actual value stored alongside each pointer's address, so it can check for violations of these rules.

Lifetimes are a static approximation of provenance. They are erased after being validated by the borrow checker, and do not exist in Miri or have any impact on what transformations the optimizer may perform. In other words, the provenance rules allow a superset of what the borrow checker allows.

There has been discussion of doing this with MIRI, which would be easier than all of rustc.

This issue has been fixed: https://github.com/rust-lang/miri/issues/2964

Actually, I've done more advanced tests with MIRI (see https://github.com/rust-lang/miri/issues/2920 for example) which allowed me to fix some issues. I've also made the code compatible with loom, but I didn't found the time yet to write and execute loom tests. That's on the TODO-list, and I need to track it with an issue too.

He is one of the big brains behind Miri, which is a interpreter that runs on the MIR (compiler representation between human code and asm/machine code) and detects undefined behavior. Super useful tool for language safety, pretty interesting on its own.

I would also run your tests in Miri (https://github.com/rust-lang/miri) to try to cover more bases.

You can run miri and it will tell you if the given run triggered any undefined behavior. It will not analyze it for every possible use of the code, but checking for the presence of this specific issue using it should be fairly simple.