Inheritance of interfaces

[Borneq]

I have unit1, where is

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1.  Intf1 = interface
2.     methods knows by unit1, for example for Linux and Windows
3.  end;
4.  
5.  TMyClass1 = class(TInterfacdedObject,Intf1)
6.  
7.  end;
8.  

unit2, where is

Code: Pascal  [Select][+][-]

1.  Intf2 = interface(Intf1)
2.     methods knows by unit2, for example only for Windows
3.  end;
4.  
5.  TMyClass2 = class(TInterfacdedObject,Intf2)
6. or better
7.  TMyClass2 = class(TMyClass1, Intf2)
8.  end;
9.  

It is correct? TMyClass2 has TMyClass1 fields only once?
I prefer TMyClass2 = class(TMyClass1, Intf2) to using TMyClass1 in methods not knowing unit2 and works on TMyClass2/

[ASerge]

Code: Pascal  [Select][+][-]

1.  TMyClass2 = class(TInterfacdedObject,Intf2)
2. or better
3.  TMyClass2 = class(TMyClass1, Intf2)

Better TMyClass2 = class(TMyClass1, Intf2, Intf1)