Unsafe rules all over

[rcseacord]

I think there are going to be a ton of rules that involve unsafe code. I'm working on one now in the Values chapter.

I think we should keep these rules in the appropriate chapters based on, for example, where the undefined behavior is defined in the FLS.

I think the unsafe chapter should just deal with specific issues surrounding Unsafe that are raised in the Unsafe chapter of the FLS.

We can then tag all of these with an "unsafe" tag.

For the first edition, we'll probably have a rule in Unsafe that says "don't use Unsafe code" which will be advisory. These more specific unsafe rules will be required or mandatory, so this will be a layering thing.
Even if the "don't use Unsafe code" is required, a user could still provide a deviation so it is worth it to have the layered rules.

[PLeVasseur]

Yep, this seems reasonable. Thanks for bringing it up.

Feel free to add the "unsafe" tag for now in conf.py.

[rcseacord]

from @felix91gr

Since we're on the topic of unsafe operations, I think pointing to the body of work of the Operational Semantics team could help. They're basically tasked with defining what the semantics of Unsafe Rust are.

Here are the topics for which consensus has been reached: https://github.com/rust-lang/opsem-team/blob/main/fcps.md
The opsem Zulip channel: https://rust-lang.zulipchat.com/#narrow/stream/136281-t-opsem
The Unsafe Coding Guidelines repo has multiple resources that may help here as well: https://github.com/rust-lang/unsafe-code-guidelines