Macro declare_late_lint_pass 

macro_rules! declare_late_lint_pass {
    ([], [$($(#[$attr:meta])* fn $name:ident($($param:ident: $arg:ty),*);)*]) => { ... };
}

Trait for types providing lint checks.

Each check method checks a single syntax node, and should not invoke methods recursively (unlike Visitor). By default they do nothing.