CFE accepts implicit invocation of .call getter via extension

[stereotype441]

The following code produces an error in the analyzer, but no error in the CFE:

class C {}
extension on C? {
  void Function() get call => () {}; // (1)
}
f(C? c) {
  c(); // ERROR: The expression doesn't evaluate to a function, so it can't be invoked.
}

I believe the CFE behavior is correct. c() should be considered equivalent to c.call(), and since call is a getter defined on type C?, it should be allowed. EDIT: analyzer behavior is correct - see Leaf's comment below.

Note that if line (1) is changed to void call() {} (which should be equivalent), then both the analyzer and CFE agree that there is no error.

[leafpetersen]

I believe the analyzer behavior is correct here, and the CFE is missing an error. See sections 13.5 and 17.15.5 here.

[stereotype441]

@leafpetersen oops, you are right. Here's the relevant text from section 13.5 (The call Member of an Extension) of the spec:

In particular, i' cannot be an invocation of an extension getter whose return type is a function type, Function, or dynamic.