{"ast_node_type":"variable","tokens":[{"end":87,"kind":"keyword","start":0,"text":"let"}]}
        let last_expr = block.tail_expr().or_else(|| match block.statements().last()? {
    fn collect_block(&mut self, block: &ast::BlockExpr) -> Option<()> {
            ast::Stmt::ExprStmt(stmt) => stmt.expr(),