A value of type 'Future<bool>' can't be returned from the function because it has a return type of 'Future<void>'

As I have observed when I am running the same code

Future<bool> foo() async => true;

Future<void> bar() {
  return foo(); // Works
}

Future<void> baz() async {
  // return foo(); // Error
}

void main() {
  print("direct =====${foo()}");
  print("bar==========${bar()}");
  print("bazz========${baz()}");
}

The response is

direct =====Instance of '_Future<bool>'
bar==========Instance of '_Future<bool>'
bazz========Instance of '_Future<void>'

this signifies that when the async keyword is not present it takes the return type of the returning value.

But of the bazz function it gives a quick fix to make the function

Future<Future<bool>>

so when async is added the function return type is taken as the main type

Future<bool> foo() async => true;

First Case

Future<void> bar()  {
  return foo(); // Works
}

For the code above, the return of Future<void> bar() can return foo(), because the bar() not return directly the value of foo(), so the bar() can deal with foo() without no problem.

But, in the second case:

Future<void> baz() async {
  return foo(); // Error
}

The code above is return directly the generic type of foo() because the function of baz() include async tag, so it will be trouble with the baz() as Future<void>, which is we know that foo() as Future<bool>