{"ast_node_type":"variable","tokens":[{"end":66,"kind":"keyword","start":0,"text":"let"}]}
        let (span, expr) = self.parse_expr_prefix_common(box_kw)?;
    fn parse_expr_box(&mut self, box_kw: Span) -> PResult<'a, (Span, ExprKind)> {
        // Make a multipart suggestion instead of `span_to_snippet` in case source isn't available