Support concrete members

[rrousselGit]

Multiple issues are requesting support for members implemented on the user-defined class directly (#65 #11 #33)

These are basically all the same issue: supporting concrete members.

This could be done by adding a concrete constructor on the user-defined class, and make the generated class extends the user-defined class using this constructor:

@freezed
abstract class Concrete with _$Concrete {
  Concrete._();
  factory Concrete(int value) = _Concrete;

  void method() {
  }
}

[rrousselGit]

I don't see any way to check if toString is the default implementation or not.

Any thought @passy?

[rrousselGit]

Actually, I've found a way to do that.

It involves traversing all the supertypes to see if they define a toString method though – that's pretty expensive.