Macro rustc_ast_passes::feature_gate::gate_feature_fn

macro_rules! gate_feature_fn {
    ($visitor : expr, $has_feature : expr, $span : expr, $name : expr, $explain :
 expr, $help : expr) => { ... };
    ($visitor : expr, $has_feature : expr, $span : expr, $name : expr, $explain :
 expr) => { ... };
}