[rustc.git] / compiler / rustc_error_codes / src / error_codes / E0722.md

The `optimize` attribute was malformed.

Erroneous code example:

```compile_fail,E0722
#![feature(optimize_attribute)]

#[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:

```
#![feature(optimize_attribute)]

#[optimize(size)]
pub fn something() {}
```

See [RFC 2412] for more details.

[RFC 2412]: https://rust-lang.github.io/rfcs/2412-optimize-attr.html
Commit	Line	Data
136023e0 XL	1	The `optimize` attribute was malformed.
	2
	3	Erroneous code example:
	4
	5	```compile_fail,E0722
	6	#![feature(optimize_attribute)]
	7
	8	#[optimize(something)] // error: invalid argument
	9	pub fn something() {}
	10	```
	11
	12	The `#[optimize]` attribute should be used as follows:
	13
	14	- `#[optimize(size)]` -- instructs the optimization pipeline to generate code
	15	that's smaller rather than faster
	16
	17	- `#[optimize(speed)]` -- instructs the optimization pipeline to generate code
	18	that's faster rather than smaller
	19
	20	For example:
	21
	22	```
	23	#![feature(optimize_attribute)]
	24
	25	#[optimize(size)]
	26	pub fn something() {}
	27	```
	28
	29	See [RFC 2412] for more details.
	30
	31	[RFC 2412]: https://rust-lang.github.io/rfcs/2412-optimize-attr.html