test_types_in_equals

Missing type test for '{0}' in '=='.

The analyzer produces this diagnostic when an override of the == operator doesn't include a type test on the value of the parameter.

The following code produces this diagnostic because other is not type tested:

class C {
  final int f;

  C(this.f);

  @override
  bool operator ==(Object other) {
    return (other as C).f == f;
  }
}

Perform an is test as part of computing the return value:

class C {
  final int f;

  C(this.f);

  @override
  bool operator ==(Object other) {
    return other is C && other.f == f;
  }
}