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Rollup merge of #121304 - compiler-errors:ext, r=nnethercote

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Add docs for extension proc-macro

r? nnethercote
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Dylan DPC 2024-02-21 08:55:57 +00:00 • committed by GitHub
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14
compiler/rustc_macros/src/lib.rs
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@ -41,6 +41,20 @@ pub fn symbols(input: TokenStream) -> TokenStream {
symbols::symbols(input.into()).into() symbols::symbols(input.into()).into()
} }
/// Derive an extension trait for a given impl block. The trait name
/// goes into the parenthesized args of the macro, for greppability.
/// For example:
/// ```
/// use rustc_macros::extension;
/// #[extension(pub trait Foo)]
/// impl i32 { fn hello() {} }
/// ```
///
/// expands to:
/// ```
/// pub trait Foo { fn hello(); }
/// impl Foo for i32 { fn hello() {} }
/// ```
#[proc_macro_attribute] #[proc_macro_attribute]
pub fn extension(attr: TokenStream, input: TokenStream) -> TokenStream { pub fn extension(attr: TokenStream, input: TokenStream) -> TokenStream {
extension::extension(attr, input) extension::extension(attr, input)