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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /third_party/rust/inherent/src/lib.rs
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+//! [![github]](https://github.com/dtolnay/inherent)&ensp;[![crates-io]](https://crates.io/crates/inherent)&ensp;[![docs-rs]](https://docs.rs/inherent)
+//!
+//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github
+//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust
+//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs
+//!
+//! <br>
+//!
+//! ##### An attribute macro to make trait methods callable without the trait in scope.
+//!
+//! # Example
+//!
+//! ```rust
+//! mod types {
+//! use inherent::inherent;
+//!
+//! trait Trait {
+//! fn f(self);
+//! }
+//!
+//! pub struct Struct;
+//!
+//! #[inherent]
+//! impl Trait for Struct {
+//! pub fn f(self) {}
+//! }
+//! }
+//!
+//! fn main() {
+//! // types::Trait is not in scope, but method can be called.
+//! types::Struct.f();
+//! }
+//! ```
+//!
+//! Without the `inherent` macro on the trait impl, this would have failed with the
+//! following error:
+//!
+//! ```console
+//! error[E0599]: no method named `f` found for type `types::Struct` in the current scope
+//! --> src/main.rs:18:19
+//! |
+//! 8 | pub struct Struct;
+//! | ------------------ method `f` not found for this
+//! ...
+//! 18 | types::Struct.f();
+//! | ^
+//! |
+//! = help: items from traits can only be used if the trait is implemented and in scope
+//! = note: the following trait defines an item `f`, perhaps you need to implement it:
+//! candidate #1: `types::Trait`
+//! ```
+//!
+//! The `inherent` macro expands to inherent methods on the `Self` type of the trait
+//! impl that forward to the trait methods. In the case above, the generated code
+//! would be:
+//!
+//! ```rust
+//! # trait Trait {
+//! # fn f(self);
+//! # }
+//! #
+//! # pub struct Struct;
+//! #
+//! # impl Trait for Struct {
+//! # fn f(self) {}
+//! # }
+//! #
+//! impl Struct {
+//! pub fn f(self) {
+//! <Self as Trait>::f(self)
+//! }
+//! }
+//! ```
+
+#![doc(html_root_url = "https://docs.rs/inherent/1.0.7")]
+#![allow(
+ clippy::default_trait_access,
+ clippy::module_name_repetitions,
+ clippy::needless_doctest_main,
+ clippy::needless_pass_by_value
+)]
+
+extern crate proc_macro;
+
+mod expand;
+mod parse;
+mod verbatim;
+
+use proc_macro::TokenStream;
+use syn::parse::Nothing;
+use syn::parse_macro_input;
+
+use crate::parse::TraitImpl;
+
+#[proc_macro_attribute]
+pub fn inherent(args: TokenStream, input: TokenStream) -> TokenStream {
+ parse_macro_input!(args as Nothing);
+ let input = parse_macro_input!(input as TraitImpl);
+ expand::inherent(input).into()
+}