Function syntax::ext::tt::macro_rules::generic_extension[][src]

Important traits for Box<W>
fn generic_extension<'cx>(
    cx: &'cx mut ExtCtxt,
    sp: Span,
    name: Ident,
    arg: TokenStream,
    lhses: &[TokenTree],
    rhses: &[TokenTree]
) -> Box<MacResult + 'cx>
🔬 This is a nightly-only experimental API. (rustc_private)

this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via Cargo.toml instead?

Given lhses and rhses, this is the new macro we create