diff --git a/library/core/src/macros/mod.rs b/library/core/src/macros/mod.rs index cfc1cabe229..3b026bc0e0f 100644 --- a/library/core/src/macros/mod.rs +++ b/library/core/src/macros/mod.rs @@ -1315,22 +1315,41 @@ macro_rules! cfg { /// Parses a file as an expression or an item according to the context. /// - /// The file is located relative to the current file (similarly to how - /// modules are found). The provided path is interpreted in a platform-specific - /// way at compile time. So, for instance, an invocation with a Windows path - /// containing backslashes `\` would not compile correctly on Unix. + /// **Warning**: For multi-file Rust projects, the `include!` macro is probably not what you + /// are looking for. Usually, multi-file Rust projects use + /// [modules](https://doc.rust-lang.org/reference/items/modules.html). Multi-file projects and + /// modules are explained in the Rust-by-Example book + /// [here](https://doc.rust-lang.org/rust-by-example/mod/split.html) and the module system is + /// explained in the Rust Book + /// [here](https://doc.rust-lang.org/book/ch07-02-defining-modules-to-control-scope-and-privacy.html). /// - /// Using this macro is often a bad idea, because if the file is - /// parsed as an expression, it is going to be placed in the - /// surrounding code unhygienically. This could result in variables - /// or functions being different from what the file expected if - /// there are variables or functions that have the same name in - /// the current file. + /// The included file is placed in the surrounding code + /// [unhygienically](https://doc.rust-lang.org/reference/macros-by-example.html#hygiene). If + /// the included file is parsed as an expression and variables or functions share names across + /// both files, it could result in variables or functions being different from what the + /// included file expected. + /// + /// The included file is located relative to the current file (similarly to how modules are + /// found). The provided path is interpreted in a platform-specific way at compile time. So, + /// for instance, an invocation with a Windows path containing backslashes `\` would not + /// compile correctly on Unix. + /// + /// # Uses + /// + /// The `include!` macro is primarily used for two purposes. It is used to include + /// documentation that is written in a separate file and it is used to include [build artifacts + /// usually as a result from the `build.rs` + /// script](https://doc.rust-lang.org/cargo/reference/build-scripts.html#outputs-of-the-build-script). + /// + /// When using the `include` macro to include stretches of documentation, remember that the + /// included file still needs to be a valid rust syntax. It is also possible to + /// use the [`include_str`] macro as `#![doc = include_str!("...")]` (at the module level) or + /// `#[doc = include_str!("...")]` (at the item level) to include documentation from a plain + /// text or markdown file. /// /// # Examples /// - /// Assume there are two files in the same directory with the following - /// contents: + /// Assume there are two files in the same directory with the following contents: /// /// File 'monkeys.in': ///