private_named_parameter_duplicate_public_name

The corresponding public name '{0}' is already the name of another parameter.

The analyzer produces this diagnostic when a private named parameter (leading _) has a corresponding public name that conflicts with an existing parameter name in the same parameter list.

The following code produces this diagnostic because the private named parameter _x's public name is x, which conflicts with the existing parameter named x:

class C {
  int? _x;
  C({int? x, this._x});
  int? get x => _x;
}

Rename one of the two parameters.