Abstract functions in child classes

[Adam]

To sort of put my two cents back in, and also to be one of those "D
should be like Java!" advocates, the problem is largely that a class
that inherits from an abstract and does *not* override some abstract
member becomes implicitly (to the user) abstract.

The way abstracts work in Java is that, in order to maintain that
"child" is an abstract (so that the actual implementation is
GrandChild), you must declare that both Child is an abstract class
and redeclare the function in question.

Now, perhaps there are good reasons in D for not requiring Child to
be declared abstract, but I'm not sure what they are. If a class
having any members that are abstract is implicitly abstract, then
the programmer should probably have to declare that the class is
abstract, as well.

The problem I ran into is that, until instantiation, the only way I
knew that Child was abstract would have been to go look at Parent
and see that I had forgotten to override a method.

Overall, the behavior seems "unexpected" (even if it's a personal
problem).