False positive for one_member_abstracts

[lexaknyazev]

Docs say:

Avoid defining a one-member abstract class when a simple function will do.

I don't think there's a way of avoiding one-member abstracts when they are used as "interfaces" like this:

abstract class Fooable { // one_member_abstracts 
  void foo();
}

void main() {
  Object o;
  if (o is Fooable) {
    o.foo();
  }
}

[pq]

/cc @munificent

[munificent]

Yeah, I'm not surprised there are false positives. It is an "AVOID" and not a "DON'T" rule, after all.

[pq]

I think this is working as intended and a case where a judicious //ignore is the right solution. (Ideally with a doc comment.)