Uncaught Error: Expected a value of type 'SharedWorkerGlobalScope', but got one of type 'Window'

[westito]

SharedWorkerGlobalScope throws Uncaught Error: Expected a value of type 'SharedWorkerGlobalScope', but got one of type 'Window' exception. I discovered this issue in a Flutter project, but I can reproduce on bare Dart.
It worked some months ago.

errors.dart:248 Uncaught Error: Expected a value of type 'SharedWorkerGlobalScope', but got one of type 'Window'
    at Object.throw_ [as throw] (errors.dart:248:21)
    at Object.castError (errors.dart:84:3)
    at Object.cast [as as] (operations.dart:452:10)
    at Function.as_C [as as] (classes.dart:635:14)
    at Function.get instance [as instance] (html_dart2js.dart:28187:24)
    at main$ (main.dart:4:42)
    at main.dart.bootstrap.js:267:10
    at Array.forEach (<anonymous>)
    at window.$dartRunMain (main.dart.bootstrap.js:266:32)
    at <anonymous>:1:8
    at Object.runMain (client.js:8805:21)
    at client.js:24459:19
    at _wrapJsFunctionForAsync_closure.$protected (client.js:3475:15)
    at _wrapJsFunctionForAsync_closure.call$2 (client.js:11564:12)
    at Object._asyncStartSync (client.js:3439:20)
    at main__closure4.$call$body$main__closure (client.js:24472:16)
    at main__closure4.call$1 (client.js:24398:19)
    at StaticClosure._rootRunUnary (client.js:3843:16)
    at _CustomZone.runUnary$2$2 (client.js:12970:39)
    at _CustomZone.runUnaryGuarded$1$2 (client.js:12917:14)
    at _ControllerSubscription._sendData$1 (client.js:12504:19)
    at _DelayedData.perform$1 (client.js:12686:59)
    at _PendingEvents_schedule_closure.call$0 (client.js:12735:14)
    at Object._microtaskLoop (client.js:3681:24)
    at StaticClosure._startMicrotaskLoop (client.js:3687:11)
    at _AsyncRun__initializeScheduleImmediate_internalCallback.call$1 (client.js:11440:9)
    at invokeClosure (client.js:1274:26)
    at MutationObserver.<anonymous> (client.js:1293:18)

Reproduce:

• dart create -t web-simple worker_sample
• Add final worker = SharedWorkerGlobalScope.instance; to main()
• Run

Dart SDK version: 2.16.2 (stable) (Tue Mar 22 13:15:13 2022 +0100) on "macos_x64"
MacOS 12.3.1 (21E258)
Chrome 100.0.4896.127 (Hivatalos verzió) (arm64)

[westito]

My bad. SharedWorkerGlobalScope.instance only return SharedWorker if code run as worker. Returns Window otherwise. I keep this issue open because would be nice to have a type check and throw more informative exception about it.