iterable_contains_unrelated_type
Invocation of Iterable<E>.contains with references of unrelated types.
Details
#NOTE: This rule is removed in Dart 3.3.0; it is no longer functional.
DON'T invoke contains on Iterable with an instance of different type
than the parameter type.
Doing this will invoke == on its elements and most likely will return false.
BAD:
dart
void someFunction() {
var list = <int>[];
if (list.contains('1')) print('someFunction'); // LINT
}BAD:
dart
void someFunction3() {
List<int> list = <int>[];
if (list.contains('1')) print('someFunction3'); // LINT
}BAD:
dart
void someFunction8() {
List<DerivedClass2> list = <DerivedClass2>[];
DerivedClass3 instance;
if (list.contains(instance)) print('someFunction8'); // LINT
}BAD:
dart
abstract class SomeIterable<E> implements Iterable<E> {}
abstract class MyClass implements SomeIterable<int> {
bool badMethod(String thing) => this.contains(thing); // LINT
}GOOD:
dart
void someFunction10() {
var list = [];
if (list.contains(1)) print('someFunction10'); // OK
}GOOD:
dart
void someFunction1() {
var list = <int>[];
if (list.contains(1)) print('someFunction1'); // OK
}GOOD:
dart
void someFunction4() {
List<int> list = <int>[];
if (list.contains(1)) print('someFunction4'); // OK
}GOOD:
dart
void someFunction5() {
List<ClassBase> list = <ClassBase>[];
DerivedClass1 instance;
if (list.contains(instance)) print('someFunction5'); // OK
}
abstract class ClassBase {}
class DerivedClass1 extends ClassBase {}GOOD:
dart
void someFunction6() {
List<Mixin> list = <Mixin>[];
DerivedClass2 instance;
if (list.contains(instance)) print('someFunction6'); // OK
}
abstract class ClassBase {}
abstract class Mixin {}
class DerivedClass2 extends ClassBase with Mixin {}GOOD:
dart
void someFunction7() {
List<Mixin> list = <Mixin>[];
DerivedClass3 instance;
if (list.contains(instance)) print('someFunction7'); // OK
}
abstract class ClassBase {}
abstract class Mixin {}
class DerivedClass3 extends ClassBase implements Mixin {}
Enable
#To enable the iterable_contains_unrelated_type rule,
add iterable_contains_unrelated_type under linter > rules in your
analysis_options.yaml file:
analysis_options.yaml
yaml
linter:
rules:
- iterable_contains_unrelated_typeIf you're instead using the YAML map syntax to configure linter rules,
add iterable_contains_unrelated_type: true under linter > rules:
analysis_options.yaml
yaml
linter:
rules:
iterable_contains_unrelated_type: true