Is there a reason for this:

class TBase
   FBar: TObject;
end;
class TChild(TBase)
   function GetBar: TChildObject; // does just a typecast
   // provide a property Bar to avoid type-casts
   property Bar: TChildObject
     read GetBar
     write FBar; // this doesn't work
end;

I understand there is a rule for property and variable type to match exactly...

But in the above case that rule would not be needed? Since FBar: TOBject is a base class of TChildObject, it can store any object that can be assigned to Bar.

Martin

Delphi compatibility?

Its mode objfpc...

It's not a big thing.

It's only about how many extra getter methods you'll end up having in the declaration. And therefore how much extra code one has to read.

Of course on the day you write it => no issue, you know it's a forwarder with no function, you fold it away...
But one day in the future, when you revisit the code..., you will not remember.