How can I write crate-wide documentation?

Question

In order to ensure that all public artifacts of my crate are documented (if minimally to start with), I specified #![deny(missing_docs)] in my lib.rs

Answer 1

I found the hidden nugget in the book's Publishing a Crate to Crates.io section.

Regular documentation comments (starting with ///) document the next item, however a crate is nobody's next.

The solution is to switch to using another kind of comment, this time starting with //!, which documents the enclosing item.

And suddenly it works:

#![deny(missing_docs)]

//! Hello world example for Rust.

fn main() {
    println!("Hello world!");
}