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unrelated_type_equality_checks

稳定
核心

对不相关类型的引用调用相等操作符 ==

详细信息

#

不要 比较不相关类型的引用是否相等。

比较不同类型(彼此非子类型)的引用是否相等,很可能返回 false,这可能并非编程者的意图。

package:fixnum 中的 Int64Int32 允许与 int 比较,前提是 int 在右侧。Linter 将此视为特例。

不良示例

dart
void someFunction() {
  var x = '1';
  if (x == 1) print('someFunction'); // LINT
}

不良示例

dart
void someFunction1() {
  String x = '1';
  if (x == 1) print('someFunction1'); // LINT
}

不良示例

dart
void someFunction13(DerivedClass2 instance) {
  var other = DerivedClass3();

  if (other == instance) print('someFunction13'); // LINT
}

class ClassBase {}

class DerivedClass1 extends ClassBase {}

abstract class Mixin {}

class DerivedClass2 extends ClassBase with Mixin {}

class DerivedClass3 extends ClassBase implements Mixin {}

良好示例

dart
void someFunction2() {
  var x = '1';
  var y = '2';
  if (x == y) print(someFunction2); // OK
}

良好示例

dart
void someFunction3() {
  for (var i = 0; i < 10; i++) {
    if (i == 0) print(someFunction3); // OK
  }
}

良好示例

dart
void someFunction4() {
  var x = '1';
  if (x == null) print(someFunction4); // OK
}

良好示例

dart
void someFunction7() {
  List someList;

  if (someList.length == 0) print('someFunction7'); // OK
}

良好示例

dart
void someFunction8(ClassBase instance) {
  DerivedClass1 other;

  if (other == instance) print('someFunction8'); // OK
}

良好示例

dart
void someFunction10(unknown) {
  var what = unknown - 1;
  for (var index = 0; index < unknown; index++) {
    if (what == index) print('someFunction10'); // OK
  }
}

良好示例

dart
void someFunction11(Mixin instance) {
  var other = DerivedClass2();

  if (other == instance) print('someFunction11'); // OK
  if (other != instance) print('!someFunction11'); // OK
}

class ClassBase {}

abstract class Mixin {}

class DerivedClass2 extends ClassBase with Mixin {}

启用

#

要启用 unrelated_type_equality_checks 规则,请在你的 analysis_options.yaml 文件中的 linter > rules 下添加 unrelated_type_equality_checks

analysis_options.yaml
yaml
linter:
  rules:
    - unrelated_type_equality_checks

如果你使用 YAML 映射语法配置 Linter 规则,请在 linter > rules 下添加 unrelated_type_equality_checks: true

analysis_options.yaml
yaml
linter:
  rules:
    unrelated_type_equality_checks: true