frontmatter

The tracking issue for this feature is: #136889

The frontmatter feature allows an extra metadata block at the top of files for consumption by external tools. For example, it can be used by cargo-script files to specify dependencies.

#!/usr/bin/env -S cargo -Zscript
---
[dependencies]
libc = "0.2.172"
---
#![feature(frontmatter)]
mod libc { pub type c_int = i32; }

fn main() {
    let x: libc::c_int = 1i32;
}