avoid-unrelated-type-assertions

added in: 1.6.0 warning

Warns about unrelated usages of is operator.

Config

Set ignore-mixins (default is false) to exclude mixins from the rule checks.

dart_code_linter:
  ...
  rules:
    - avoid-unrelated-type-assertions:
        ignore-mixins: false

Example

Bad:

class Animal {}

class NotAnimal {}

class HomeAnimal extends Animal {}

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

  final Animal animal = Animal();

  void main() {
    final result = regularString is int; // LINT
    final result2 = myList is List<String>; // LINT

    final result3 = animal is NotAnimal; // LINT
  }

  void patterns() {
    final animal = Animal();

    if (animal case HomeAnimal result) {}
    if (animal case HomeAnimal()) {}
    if (animal case NotAnimal result) {} // LINT
    if (animal case NotAnimal()) {} // LINT
  }
}

Good:

class Animal {}

class HomeAnimal extends Animal {}

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

  final Animal animal = Animal();

  void main() {
    final result = regularString is String;
    final result2 = myList is List<int>;

    final result3 = animal is Object;
  }

  void patterns() {
    final animal = Animal();

    if (animal case HomeAnimal result) {}
    if (animal case HomeAnimal()) {}
  }
}