private_named_parameter_without_public_name

A private named parameter must be a public identifier after removing the leading underscore.

The analyzer produces this diagnostic when the name of a named parameter starts with an underscore and the result of removing the underscore isn't a valid public identifier.

The following code produces this diagnostic because the named parameter _2legit without the _ is 2legit, which isn't a valid public identifier:

class C {
  final int? _2legit;
  C({this._2legit = 0});
  int? get twoLegit => _2legit;
}

Rename the parameter so that the character following the leading underscore is a letter.