#[parity]Expand description
Attribute on any named item with no enclosing impl block: a free fn,
or a type definition (struct, enum, type alias). The implementation
path becomes module_path!()::<name> (resolved at compile time of the
user crate, since module_path!() expands in place). For a type
alias re-exporting a foreign type, <name> is the local alias — so the
recorded implementation is always a symbol in the user’s own crate.