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test_types_in_equals

Contents
Stable

Test type of argument in operator ==(Object other).

Details

#

DO test type of argument in operator ==(Object other).

Not testing the type might result in runtime type errors which will be unexpected for consumers of your class.

BAD:

dart
class Field {
}

class Bad {
  final Field someField;

  Bad(this.someField);

  @override
  bool operator ==(Object other) {
    Bad otherBad = other as Bad; // LINT
    bool areEqual = otherBad != null && otherBad.someField == someField;
    return areEqual;
  }

  @override
  int get hashCode {
    return someField.hashCode;
  }
}

GOOD:

dart
class Field {
}

class Good {
  final Field someField;

  Good(this.someField);

  @override
  bool operator ==(Object other) {
    if (identical(this, other)) {
      return true;
    }
    return other is Good &&
        this.someField == other.someField;
  }

  @override
  int get hashCode {
    return someField.hashCode;
  }
}

Enable

#

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

analysis_options.yaml
yaml
linter:
  rules:
    - test_types_in_equals

If you're instead using the YAML map syntax to configure linter rules, add test_types_in_equals: true under linter > rules:

analysis_options.yaml
yaml
linter:
  rules:
    test_types_in_equals: true

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-03-07. View source or report an issue.