use_setters_to_change_properties

The method is used to change a property.

The analyzer produces this diagnostic when a method is used to set the value of a field, or a function is used to set the value of a top-level variable, and nothing else.

The following code produces this diagnostic because the method setF is used to set the value of the field _f and does no other work:

class C {
  int _f = 0;

  void setF(int value) => _f = value;
}

Convert the method to a setter:

class C {
  int _f = 0;

  set f(int value) => _f = value;
}