#trait #scope

macro no-std inherent

Make trait methods callable without the trait in scope

10 releases (3 stable)

1.0.2 Aug 3, 2022
1.0.1 Apr 1, 2022
1.0.0 Aug 20, 2021
0.1.6 Dec 11, 2020
0.1.0 Jul 14, 2019

#140 in Rust patterns

Download history 7210/week @ 2022-06-08 5778/week @ 2022-06-15 5638/week @ 2022-06-22 4223/week @ 2022-06-29 4630/week @ 2022-07-06 4297/week @ 2022-07-13 4118/week @ 2022-07-20 4034/week @ 2022-07-27 5887/week @ 2022-08-03 5146/week @ 2022-08-10 4682/week @ 2022-08-17 6188/week @ 2022-08-24 5277/week @ 2022-08-31 5431/week @ 2022-09-07 5401/week @ 2022-09-14 6019/week @ 2022-09-21

23,330 downloads per month
Used in 2 crates (via glean)

MIT/Apache

13KB
197 lines

#[inherent]

github crates.io docs.rs build status

This crate provides an attribute macro to make trait methods callable without the trait in scope.

[dependencies]
inherent = "1.0"

Example

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:

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:

impl Struct {
    pub fn f(self) {
        <Self as Trait>::f(self)
    }
}

License

Licensed under either of Apache License, Version 2.0 or MIT license at your option.
Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in this crate by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.

Dependencies

~220–630KB
~15K SLoC