{"ast_node_type":"variable","tokens":[{"end":49,"kind":"keyword","start":0,"text":"let"}]}
        let ctor = Constructor::Struct; // tuples
    (@ctor($($args:tt)*) ( $($fields:tt)* ) $($rest:tt)*) => {{
        pats!(@pat($($args)*, ctor:ctor) ( $($fields)* ) $($rest)*)