Error code E0722

The optimize attribute was malformed.

Erroneous code example:

#![allow(unused)] #![feature(optimize_attribute)] fn main() { #[optimize(something)] // error: invalid argument pub fn something() {} }

The #[optimize] attribute should be used as follows:

  • #[optimize(size)] -- instructs the optimization pipeline to generate code that's smaller rather than faster

  • #[optimize(speed)] -- instructs the optimization pipeline to generate code that's faster rather than smaller

For example:

#![allow(unused)] #![feature(optimize_attribute)] fn main() { #[optimize(size)] pub fn something() {} }

See RFC 2412 for more details.