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no_self_assignments

verified_userStable

Don't assign a variable to itself.

Details

#

DON'T assign a variable to itself. Usually this is a mistake.

BAD:

dart 
class C {
  int x;
​
  C(int x) {
    x = x;
  }
}

GOOD:

dart 
class C {
  int x;
​
  C(int x) : x = x;
}

GOOD:

dart 
class C {
  int x;
​
  C(int x) {
    this.x = x;
  }
}

BAD:

dart 
class C {
  int _x = 5;
​
  int get x => _x;
​
  set x(int x) {
    _x = x;
    _customUpdateLogic();
  }
​
  void _customUpdateLogic() {
    print('updated');
  }
​
  void example() {
    x = x;
  }
}

GOOD:

dart 
class C {
  int _x = 5;
​
  int get x => _x;
​
  set x(int x) {
    _x = x;
    _customUpdateLogic();
  }
​
  void _customUpdateLogic() {
    print('updated');
  }
​
  void example() {
    _customUpdateLogic();
  }
}

BAD:

dart 
class C {
  int x = 5;
​
  void update(C other) {
    this.x = this.x;
  }
}

GOOD:

dart 
class C {
  int x = 5;
​
  void update(C other) {
    this.x = other.x;
  }
}

Enable

#

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

analysis_options.yaml
yaml 
linter:
  rules:
    - no_self_assignments

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

analysis_options.yaml
yaml 
linter:
  rules:
    no_self_assignments: true

Unless stated otherwise, the documentation on this site reflects Dart 3.9.2. Report an issue.