third_party/rust/inherent/README.md

   1 \#\[inherent\]
   2 ==============
   3
   4 [<img alt="github" src="https://img.shields.io/badge/github-dtolnay/inherent-8da0cb?style=for-the-badge&labelColor=555555&logo=github" height="20">](https://github.com/dtolnay/inherent)
   5 [<img alt="crates.io" src="https://img.shields.io/crates/v/inherent.svg?style=for-the-badge&color=fc8d62&logo=rust" height="20">](https://crates.io/crates/inherent)
   6 [<img alt="docs.rs" src="https://img.shields.io/badge/docs.rs-inherent-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs" height="20">](https://docs.rs/inherent)
   7 [<img alt="build status" src="https://img.shields.io/github/actions/workflow/status/dtolnay/inherent/ci.yml?branch=master&style=for-the-badge" height="20">](https://github.com/dtolnay/inherent/actions?query=branch%3Amaster)
   8
   9 This crate provides an attribute macro to make trait methods callable without
  10 the trait in scope.
  11
  12 ```toml
  13 [dependencies]
  14 inherent = "1.0"
  15 ```
  16
  17 ## Example
  18
  19 ```rust
  20 mod types {
  21     use inherent::inherent;
  22
  23     trait Trait {
  24         fn f(self);
  25     }
  26
  27     pub struct Struct;
  28
  29     #[inherent]
  30     impl Trait for Struct {
  31         pub fn f(self) {}
  32     }
  33 }
  34
  35 fn main() {
  36     // types::Trait is not in scope, but method can be called.
  37     types::Struct.f();
  38 }
  39 ```
  40
  41 Without the `inherent` macro on the trait impl, this would have failed with the
  42 following error:
  43
  44 ```console
  45 error[E0599]: no method named `f` found for type `types::Struct` in the current scope
  46   --> src/main.rs:18:19
  47    |
  48 8  |     pub struct Struct;
  49    |     ------------------ method `f` not found for this
  50 ...
  51 18 |     types::Struct.f();
  52    |                   ^
  53    |
  54    = help: items from traits can only be used if the trait is implemented and in scope
  55    = note: the following trait defines an item `f`, perhaps you need to implement it:
  56            candidate #1: `types::Trait`
  57 ```
  58
  59 The `inherent` macro expands to inherent methods on the `Self` type of the trait
  60 impl that forward to the trait methods. In the case above, the generated code
  61 would be:
  62
  63 ```rust
  64 impl Struct {
  65     pub fn f(self) {
  66         <Self as Trait>::f(self)
  67     }
  68 }
  69 ```
  70
  71 <br>
  72
  73 #### License
  74
  75 <sup>
  76 Licensed under either of <a href="LICENSE-APACHE">Apache License, Version
  77 2.0</a> or <a href="LICENSE-MIT">MIT license</a> at your option.
  78 </sup>
  79
  80 <br>
  81
  82 <sub>
  83 Unless you explicitly state otherwise, any contribution intentionally submitted
  84 for inclusion in this crate by you, as defined in the Apache-2.0 license, shall
  85 be dual licensed as above, without any additional terms or conditions.
  86 </sub>