doc_spotlight - The Rust Unstable Book

# `doc_spotlight`

The tracking issue for this feature is: #45040

The `doc_spotlight` feature allows the use of the `spotlight` parameter to the `#[doc]` attribute, to "spotlight" a specific trait on the return values of functions. Adding a `#[doc(spotlight)]` attribute to a trait definition will make rustdoc print extra information for functions which return a type that implements that trait. This attribute is applied to the `Iterator`, `io::Read`, and `io::Write` traits in the standard library.

You can do this on your own traits, like this:

    #![feature(doc_spotlight)]

    #[doc(spotlight)]
    pub trait MyTrait {}

    pub struct MyStruct;
    impl MyTrait for MyStruct {}

    /// The docs for this function will have an extra line about `MyStruct` implementing `MyTrait`,
    /// without having to write that yourself!
    pub fn my_fn() -> MyStruct { MyStruct }

This feature was originally implemented in PR #45039.