[rustc.git] / src / doc / rust-by-example / src / attribute / unused.md

# `dead_code`

The compiler provides a `dead_code`
[*lint*][lint] that will warn
about unused functions. An *attribute* can be used to disable the lint.

```rust,editable
fn used_function() {}

// `#[allow(dead_code)]` is an attribute that disables the `dead_code` lint
#[allow(dead_code)]
fn unused_function() {}

fn noisy_unused_function() {}
// FIXME ^ Add an attribute to suppress the warning

fn main() {
    used_function();
}
```

Note that in real programs, you should eliminate dead code. In these examples
we'll allow dead code in some places because of the interactive nature of the
examples.

[lint]: https://en.wikipedia.org/wiki/Lint_%28software%29
Commit	Line	Data
2c00a5a8 XL	1	# `dead_code`
	2
	3	The compiler provides a `dead_code`
	4	[lint][lint] that will warn
	5	about unused functions. An attribute can be used to disable the lint.
	6
	7	```rust,editable
	8	fn used_function() {}
	9
	10	// `#[allow(dead_code)]` is an attribute that disables the `dead_code` lint
	11	#[allow(dead_code)]
	12	fn unused_function() {}
	13
	14	fn noisy_unused_function() {}
	15	// FIXME ^ Add an attribute to suppress the warning
	16
	17	fn main() {
	18	used_function();
	19	}
	20	```
	21
	22	Note that in real programs, you should eliminate dead code. In these examples
	23	we'll allow dead code in some places because of the interactive nature of the
	24	examples.
	25
	26	[lint]: https://en.wikipedia.org/wiki/Lint_%28software%29