falcon

Rules / Style / unnecessary-this

unnecessary-this

lint/style/unnecessary-this
recommended
Same as unnecessary_this · Dart lints

Flags a redundant this. qualifier on member access.

Writing this.x or this.m() is only necessary when a parameter or local variable in scope shadows the member name; otherwise the qualifier is noise that most Dart style guides ask you to drop. The analysis is deliberately conservative: it over-approximates the shadow set, treating every parameter, local variable, loop/catch/pattern binding, and closure parameter anywhere in the member as a potential shadow, so a name that could plausibly be shadowed is never flagged. Constructor initializer lists — where this. genuinely disambiguates a field from a parameter — are not visited. Remove the this..

Invalid

example.dartdart
// `this.` where no parameter or local shadows the member.
class A {
  int x = 0;
  int y = 0;
  void m() {
    this.x = 1;
    print(this.y);
  }
  int get sum => this.x + this.y;
}

class B {
  int value = 0;
  void update(int v) {
    this.helper();
    value = v;
  }
  void helper() {}
}

class C {
  int count = 0;
  void inc() {
    this.count += 1;
  }
}
Unnecessary 'this.' qualifier.
5 void m() {
6 this.x = 1;
Unnecessary 'this.' qualifier.
6 this.x = 1;
7 print(this.y);
Unnecessary 'this.' qualifier.
8 }
9 int get sum => this.x + this.y;
Unnecessary 'this.' qualifier.
8 }
9 int get sum => this.x + this.y;
Unnecessary 'this.' qualifier.
14 void update(int v) {
15 this.helper();
Unnecessary 'this.' qualifier.
23 void inc() {
24 this.count += 1;

Valid

example.dartdart
// `this.` needed because of a shadowing parameter or local, or no `this.`.
class A {
  int x = 0;
  void m(int x) {
    this.x = x;
  }
}

class B {
  int value = 0;
  void update() {
    var value = 5;
    this.value = value;
  }
}

class C {
  int count = 0;
  void inc() {
    count += 1;
  }
  int get doubled => count * 2;
}

class D {
  int total = 0;
  void add(int total) {
    this.total += total;
  }
}

class E {
  void run(int helper) {
    this.helper();
  }
  void helper() {}
}

How to configure

Set the severity of unnecessary-this in your falcon.json:

falcon.jsonjson
{
  "linter": {
    "rules": {
      "style": {
        "unnecessary-this": "error"
      }
    }
  }
}

Related