Macro rustc_ast_passes::feature_gate::gate_feature_post

macro_rules! gate_feature_post {
    ($visitor: expr, $feature: ident, $span: expr, $explain: expr, $help: expr) => { ... };
    ($visitor: expr, $feature: ident, $span: expr, $explain: expr) => { ... };
    (future_incompatible; $visitor: expr, $feature: ident, $span: expr, $explain: expr) => { ... };
}