pub static RUST_2021_PREFIXES_INCOMPATIBLE_SYNTAX: &'static Lint
Expand description

The rust_2021_prefixes_incompatible_syntax lint detects identifiers that will be parsed as a prefix instead in Rust 2021.



macro_rules! m {
    (z $x:expr) => ();




In Rust 2015 and 2018, z"hey" is two tokens: the identifier z followed by the string literal "hey". In Rust 2021, the z is considered a prefix for "hey".

This lint suggests to add whitespace between the z and "hey" tokens to keep them separated in Rust 2021.