exit status: 1 with stderr:
<stdin>:6:9: error: 'async' modifier is only valid when experimental concurrency is enabled async let (l, r) = (left(), right()) ^ <stdin>:8:15: warning: no 'async' operations occur within 'await' expression print(await l) ^ <stdin>:9:15: warning: no 'async' operations occur within 'await' expression print(await r) ^ <stdin>:6:28: error: expression is 'async' but is not marked with 'await' async let (l, r) = (left(), right()) ^~~~~~~~~~~~~~~~~ await <stdin>:6:29: note: call is 'async' async let (l, r) = (left(), right()) ^ <stdin>:6:37: note: call is 'async' async let (l, r) = (left(), right()) ^