Macro for_each_ast_visit_hook 

macro_rules! for_each_ast_visit_hook {
    ($macro:ident!) => { ... };
}

Higher-order macro that puts all the visit/walk hook information in a single place. The passed-in macro should have a left hand side like this:

($($visit:ident($Ty:ty $(, $extra:ident: $ExtraTy:ty)?) => $walk:ident;)*) => { ... }