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avoid-unrelated-type-casts

added in: 1.0.0
warning
Pro+
preset: recommended

Warns about unrelated usages of the as operator and cast method.

Incorrect usages of the as operator can lead to runtime exceptions and unexpected behavior.

Example​

❌ Bad:

class Example {
  final regularString = '';
  final myList = <int>[1, 2, 3];

  final Animal animal = Animal();

  void main() {
    final result = regularString as int; // LINT: Avoid unrelated 'as' cast. Target type has no overlap with the cast type.
    final result2 = myList as List<String>; // LINT: Avoid unrelated 'as' cast. Target type has no overlap with the cast type.

    final result3 = animal as NotAnimal; // LINT: Avoid unrelated 'as' cast. Target type has no overlap with the cast type.

    if (animal case Animal() as NotAnimal) {} // LINT: Avoid unrelated 'as' cast. Target type has no overlap with the cast type.
  }
}

class Animal {}

class HomeAnimal extends Animal {}

class NotAnimal {}

✅ Good:

class Example {
  final regularString = '';
  final myList = <int>[1, 2, 3];

  final Animal animal = Animal();

  void main() {
    final result = regularString;
    final result2 = myList;

    final result3 = animal;

    if (animal case Animal() as HomeAnimal) {}
  }
}

Additional Resources​