Error code E0522
The lang attribute was used in an invalid context.
Erroneous code example:
#![allow(unused)] #![feature(lang_items)] fn main() { #[lang = "cookie"] fn cookie() -> ! { // error: definition of an unknown language item: `cookie` loop {} } }
The lang attribute is intended for marking special items that are built-in to
Rust itself. This includes special traits (like Copy
and Sized
) that affect
how the compiler behaves, as well as special functions that may be automatically
invoked (such as the handler for out-of-bounds accesses when indexing a slice).