{"ast_node_type":"variable","tokens":[{"end":42,"kind":"keyword","start":0,"text":"let"}]}
    let stmt_tail_opt: Option<ast::Stmt> =
fn with_tail_expr(block: ast::BlockExpr, tail_expr: ast::Expr) -> ast::BlockExpr {
        block.tail_expr().map(|expr| make::expr_stmt(expr).into());