Extract method refactors widget with async callback incorrectly

[omarelb]

Describe the bug
In a build function, when calling extract method on a widget such as a button with an asynchronous callback (e.g. async onPressed method), the newly created method itself is marked as an async function, which is incorrect (at least in all the cases that I've used it). While the callback is asynchronous, the function that is returning the widget should not be.

To Reproduce
Steps to reproduce the behavior:

1. Create a widget such as a button with an asynchronous callback. For example:

ListTile(
  title: "Hi",
  suffixIcon: IconButton(
    onPressed: () async {
       await asyncFunction()
    },
    icon: Icon(Icons.arrow_forward),
  )
)

2. Place your cursor on IconButton, bring up the context menu, press extract method, and name the new function.

3. The IconButton will have been replaced by your new method, but it has an await keyword before it that should not be there.

Expected behavior
The new function is added in place of the IconButton without an await in front of the function call. The new function does not return a Future<Widget> but just a Widget. The new method is not an async method.

Please complete the following information:

• Operating System and version: macOS Monterey 12.2, M1 Chip
• VS Code version: 1.68.1
• Dart extension version: v3.44.0
• Dart/Flutter SDK version: Flutter 2.10.4, Dart 2.16.2

[DanTup]

Thanks, I can repro this. A smaller example without the Flutter dependency is:

void f() {
  g(() {
    return Future.value(null);
  });
  g(() async {
    await null;
  });
}

void g(Future<void> Function() func) {}

Extracting the first call to g is fine, but the second one gets the unwanted await.

[DanTup]

Fixed by dart-lang/sdk@97fa3ca. The fix is in the Dart SDK, so will show up in a Future SDK release (and not a VS Code extension update).