falcon

Rules / Style / use-super-parameters

use-super-parameters

lint/style/use-super-parameters
Same as use_super_parameters · Dart lints

Flags a constructor parameter forwarded verbatim to super(...) and used nowhere else.

Since Dart 2.17, a parameter that exists only to be passed straight through to the superclass constructor can be declared as a super parameter — super.x — which removes both the parameter declaration and the redundant super(x) argument. Doing so cuts boilerplate and keeps subclass constructors in sync with the base class automatically. The rule is conservative: it fires only when the parameter is used exactly once across the entire constructor (all initializers plus the body), forwarded either as a plain positional super argument at the matching index or as a named argument super(x: x). Convert it to a super. parameter.

Invalid

example.dartdart
// Parameters forwarded verbatim to super and used nowhere else.
class Base {
  Base(int a);
  Base.two(int a, int b);
  Base.named({int? x});
}

class A extends Base {
  A(int a) : super(a);
}

class B extends Base {
  B(int a, int b) : super.two(a, b);
}

class C extends Base {
  C({int? x}) : super.named(x: x);
}

class D extends Base {
  D(int a) : super(a);
}

class E extends Base {
  E(int a) : super(a);
}
Use a super parameter instead of forwarding a parameter to super.
8class A extends Base {
9 A(int a) : super(a);
Use a super parameter instead of forwarding a parameter to super.
12class B extends Base {
13 B(int a, int b) : super.two(a, b);
Use a super parameter instead of forwarding a parameter to super.
12class B extends Base {
13 B(int a, int b) : super.two(a, b);
Use a super parameter instead of forwarding a parameter to super.
16class C extends Base {
17 C({int? x}) : super.named(x: x);
Use a super parameter instead of forwarding a parameter to super.
20class D extends Base {
21 D(int a) : super(a);
Use a super parameter instead of forwarding a parameter to super.
24class E extends Base {
25 E(int a) : super(a);

Valid

example.dartdart
// Cases that must not be flagged.
class Base {
  Base(int a);
  Base.two(int a, int b);
}

class A extends Base {
  A(int a) : super(a) {
    print(a);
  }
}

class B extends Base {
  B(super.a);
}

class C extends Base {
  C(int value) : super(value + 1);
}

class D extends Base {
  D(int a, int b) : super.two(b, a);
}

class E extends Base {
  E(int a, int b) : super.two(a, b) {
    print(a);
    print(b);
  }
}

How to configure

Set the severity of use-super-parameters in your falcon.json:

falcon.jsonjson
{
  "linter": {
    "rules": {
      "style": {
        "use-super-parameters": "error"
      }
    }
  }
}

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