param_attrs
The tracking issue for this feature is: #60406
Allow attributes in formal function parameter position so external tools and compiler internals can take advantage of the additional information that the parameters provide.
Enables finer conditional compilation with #[cfg(..)]
and linting control of variables. Moreover, opens the path to richer DSLs created by users.
Example:
#![feature(param_attrs)] fn len( #[cfg(windows)] slice: &[u16], #[cfg(not(windows))] slice: &[u8], ) -> usize { slice.len() }