[analyzer] unnecessary nullable

[asashour]

Would it be helpful to have a hint that a type can be not nullable?

For example: if a private method has a parameter, which is always called with a non nullable type, then it is triggered.

void main() {
  _test(1);
}

void a(int i) {
  _test(i);
}

void _test(int? x) { // <--- here
  print(x);
}

[bwilkerson]

Yes, it would be helpful. Unfortunately, this requires being able to look at every invocation of the function, and for most code we can't assume that every invocation is currently being analyzed.

About the only thing we could do at this point is to provide this analysis for private functions where we know that we can find all of the invocations of the function. While this would be possible to do, it isn't clear how much value it would add.

Internally there has been some discussion of whether and how we might provide whole-world / closed-world analyses, and this would be a candidate for such a framework, but there are no concrete plans to work on such support at the moment.