field_initialized_in_parameter_and_initializer

Fields can't be initialized in both the parameter list and the initializers.

The analyzer produces this diagnostic when a field is initialized in both the parameter list and in the initializer list of a constructor.

The following code produces this diagnostic because the field f is initialized both by an initializing formal parameter and in the initializer list:

class C {
  int f;

  C(this.f) : f = 0;
}

If the field should be initialized by the parameter, then remove the initialization in the initializer list:

class C {
  int f;

  C(this.f);
}

If the field should be initialized in the initializer list and the parameter isn't needed, then remove the parameter:

class C {
  int f;

  C() : f = 0;
}

If the field should be initialized in the initializer list and the parameter is needed, then make it a normal parameter:

class C {
  int f;

  C(int g) : f = g * 2;
}

Unless stated otherwise, the documentation on this site reflects Dart 3.8.1. Page last updated on 2025-05-08. View source or report an issue.