[analyzer] Unhandled exception: Null check operator used on a null value

[incendial]

Hi, our users reported a strange null check exception dart-code-checker/dart-code-metrics#1098 and after looking at source code I'm not sure that this is the expected behaviour https://github.com/dart-lang/sdk/blob/main/pkg/analyzer/lib/src/dart/element/member.dart#L624. I've also asked for the code example that produced the exception.

Also, the Element class declares the source property as nullable.

@bwilkerson @scheglov could you please take a look?

[scheglov]

Thank you, I can reproduce it.

[incendial]

The example from our user dart-code-checker/dart-code-metrics#1098 (comment)

[scheglov]

Yes, this example is what allowed me to reproduce it!

[scheglov]

https://dart-review.googlesource.com/c/sdk/+/274603

So, this is how to reproduce it.

void foo<T>({required int a}) {}

void f() {
  foo(a: 0);
}

Fortunately, this is not the issue that I thought it is initially, with completely synthetic FunctionType and its parameters.

[incendial]

Thank you for the fast fix and the code example, the case is very interesting 🙂 !