Skip to main content

avoid-unnecessary-type-casts

added in: 1.6.0
warning
Pro+
preset: recommended

Warns about unnecessary use of the as operator and cast method.

Unnecessary type casts are either a sign of a bug (another type should be used instead or the type hierarchy should include the expected type) or are redundant and can simply be removed.

Example​

❌ Bad:

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

  void main() {
    final result = myList as List<int>; // LINT: Avoid unnecessary 'as' type cast.

    final animal = Animal();
    if (animal case HomeAnimal() as Animal) {} // LINT: Avoid unnecessary 'as' type cast.
  }
}

class Animal {}

class HomeAnimal extends Animal {}

✅ Good:

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

  void main() {
    final result = myList;

    final animal = Animal();
    if (animal case HomeAnimal()) {}
  }
}

Additional Resources​