# Error code E0535

An unknown argument was given to the `inline` attribute.

Erroneous code example:

    #[inline(unknown)] // error: invalid argument
    pub fn something() {}

    fn main() {}

The `inline` attribute only supports two arguments:

- always
- never

All other arguments given to the `inline` attribute will return this error. Example:

    #[inline(never)] // ok!
    pub fn something() {}

    fn main() {}

For more information see the `inline` Attribute section of the Reference.