pub fn walk_for<'hir, V>( v: &mut V, init: Option<&'hir Item<'hir>>, cond: Option<&'hir Expression<'hir>>, inc: Option<&'hir Expression<'hir>>, body: &'hir Statement<'hir>, ) -> V::Resultwhere V: Visitor<'hir> + ?Sized,