See the below code. (tested 3.2.3 and 3.3.1)
Is this intentionally allowed?
Technically it should work. TSubTest.Test always returns something that
fits the inherited requirement.
program Project1;
type
TFoo = class end;
TBar = class(TFoo) end;
TTest = class
function Test: TFoo; virtual; abstract;
end;
TSubTest = class(TTest)
function Test: TBar; override;
end;
function TSubTest.Test: TBar;
begin end;
begin end.
And if that is intentional, then why not also
TTest = class
procedure Test(a: TBar); virtual; abstract;
end;
TSubTest = class(TTest)
procedure Test(a: TFoo); override;
end;
This fails. Even though any TBar passed will be fine to the base and the
subclass.
And any
var sub: TSubTest
will accept TFoo too, but such a var can never hold the base class.
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