{"ast_node_type":"other","tokens":[{"end":56,"kind":"keyword","start":0,"text":"$vis:ident:"}]}
      $vis:ident: &mut $vis_ty:ident| $block:block) => {
    ($(<$K:ident: $Kb:ident>)? |&mut $self:ident: $self_ty:ty,
        #[allow(unused_parens, non_local_definitions)]