Rustdoc's Additional Features: Markdown and Doctests

is also some data in clean that doesn't correspond directly to `HIR`, such as synthetic `impl`s for auto traits and blanket `impl`s generated by the `collect-trait-impls` pass. Some additional data is stored in `html::render::context::{Context, SharedContext}`. These two types serve as ways to segregate `rustdoc`'s data for an eventual future with multithreaded doc generation, as well as just keeping things organized: * [`Context`] stores data used for generating the current page, such as its path, a list of `HTML` IDs that have been used (to avoid duplicate `id=""`), and the pointer to `SharedContext`. * [`SharedContext`] stores data that does not vary by page, such as the `tcx` pointer, and a list of all types. [`Context`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/html/render/context/struct.Context.html [didn't used to be the case]: https://github.com/rust-lang/rust/pull/80090 [`SharedContext`]: https://doc.rust-lang.org/nightly/nightly-rustc/rustdoc/html/render/context/struct.SharedContext.html ## Other Tricks Up Its Sleeve All this describes the process for generating `HTML` documentation from a Rust crate, but there are couple other major modes that `rustdoc` runs in. It can also be run on a standalone Markdown file, or it can run `doctest`s on Rust code or standalone Markdown files. For the former, it shortcuts straight to `html/markdown.rs`, optionally including a mode which inserts a Table of Contents to the output `HTML`. For the latter, `rustdoc` runs a similar partial-compilation to get relevant documentation in `test.rs`, but instead of going through the full clean and render process, it runs a much simpler crate walk to grab *just* the hand-written documentation. Combined with the aforementioned "`find_testable_code`" in `html/markdown.rs`, it builds up a collection of tests to run before handing them off to the test runner. One notable location in `test.rs` is the function `make_test`, which is where hand-written `doctest`s get transformed into something that can be executed. Some extra reading about `make_test` can be found [here](https://quietmisdreavus.net/code/2018/02/23/how-the-doctests-get-made/). ## Dotting i's And Crossing t's So that's `rustdoc`'s code in a nutshell, but there's more things in the

In addition to generating HTML documentation from Rust crates, rustdoc can also process standalone Markdown files, converting them to HTML with an optional table of contents. Furthermore, rustdoc can run doctests on both Rust code and Markdown files. This involves a partial compilation and a simplified crate walk to extract documentation. The `make_test` function in `test.rs` transforms doctests into executable code for the test runner.