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:
All other arguments given to the inline
attribute will return this error. Example:
#[inline(never)] // ok! pub fn something() {} fn main() {}
For more information about the inline attribute, https: read://doc.rust-lang.org/reference.html#inline-attributes