Rust compiler support works differently

Right, my bad, I should have qualified: not that many *compared to the entirety of crates.io*, meaning the odds of one of them being both out of date and incompatible are fairly low.

Don't take this as an endorsement of the sprawling dep trees of some Rust projects :-)

To give some hard numbers, Rust 1.85 in Ubuntu vendors 672 crates. Since that directory contains dependencies for the entire toolchain, including cargo and rustdoc, I think they're on the conservative side of the ecosystem.