An idea to mitigate attacks through malicious crates

[bascule]

@Soni

I feel like some ppl are misunderstanding feature flags and the unsafe lint (which afaik exists).

The main problems with existing unsafe lints:

• #![forbid(unsafe_code)] is not transitive
• As you pointed more or less out in the other recent rust-internals thread on this same subject, #[no_mangle] can be used for unsafe purposes without an explicit unsafe keyword.

Unless there are additional unsafe lints I'm unaware of in the core language, I feel the existing mechanisms aren't suitable for and are somewhat orthogonal to the proposed goals in this thread.