Rust Devblog 261 Official

// In your proc macro #[proc_macro] pub fn my_macro(input: TokenStream) -> TokenStream let diag = Diagnostic::new(Severity::Error, "This usage is invalid") .help("Try using `foo` instead of `bar`") .emit(); // ...

cargo script script.rs Add #!/usr/bin/env cargo-script shebang and chmod +x for executable scripts. 4. Standard library: integer::is_multiple_of What’s new: New method is_multiple_of on integer types. rust devblog 261

let x = 42u32; assert!(x.is_multiple_of(7)); assert!(!x.is_multiple_of(5)); Avoids division by zero — it’s a panic (same as % ). 5. Cargo: --ignore-rust-version flag What’s new: Build crates even if they require a newer Rust version than your current toolchain. // In your proc macro #[proc_macro] pub fn