{"ast_node_type":"other","tokens":[{"end":54,"kind":"keyword","start":0,"text":"#[allow(unused_parens,"}]}
        #[allow(unused_parens, non_local_definitions)]
      $vis:ident: &mut $vis_ty:ident| $block:block) => {
        impl<$($K: $Kb,)? $lt, $vis_ty: Visitor<$lt>> Walkable<$lt, $vis_ty> for $self_ty {