The tracking issue for this feature is: #45040

The doc_notable_trait feature allows the use of the #[doc(notable_trait)] attribute, which will display the trait in a "Notable traits" dialog for functions returning types that implement the trait. For example, this attribute is applied to the Iterator, Future, io::Read, and io::Write traits in the standard library.

You can do this on your own traits like so:


pub trait MyTrait {}

pub struct MyStruct;
impl MyTrait for MyStruct {}

/// The docs for this function will have a button that displays a dialog about
/// `MyStruct` implementing `MyTrait`.
pub fn my_fn() -> MyStruct { MyStruct }

This feature was originally implemented in PR #45039.

See also its documentation in the rustdoc book.