collection_methods_unrelated_type

Invocation of various collection methods with arguments of unrelated types.

This rule is available as of Dart 2.19.0.

Details

DON’T invoke certain collection method with an argument with an unrelated type.

Doing this will invoke == on the collection’s elements and most likely will return false.

An argument passed to a collection method should relate to the collection type as follows:

• an argument to Iterable<E>.contains should be related to E
• an argument to List<E>.remove should be related to E
• an argument to Map<K, V>.containsKey should be related to K
• an argument to Map<K, V>.containsValue should be related to V
• an argument to Map<K, V>.remove should be related to K
• an argument to Map<K, V>.[] should be related to K
• an argument to Queue<E>.remove should be related to E
• an argument to Set<E>.lookup should be related to E
• an argument to Set<E>.remove should be related to E

BAD:

void someFunction() {
  var list = <int>[];
  if (list.contains('1')) print('someFunction'); // LINT
}

BAD:

void someFunction() {
  var set = <int>{};
  set.remove('1'); // LINT
}

GOOD:

void someFunction() {
  var list = <int>[];
  if (list.contains(1)) print('someFunction'); // OK
}

GOOD:

void someFunction() {
  var set = <int>{};
  set.remove(1); // OK
}

Usage

To enable the collection_methods_unrelated_type rule, add collection_methods_unrelated_type under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - collection_methods_unrelated_type