Is this a DMD bug, or correct behavior?

[Foo Bar]

On Wednesday, 13 March 2019 at 00:50:35 UTC, Adam D. Ruppe wrote:
> On Wednesday, 13 March 2019 at 00:27:02 UTC, Foo Bar wrote:
>> I came across this strange behavior, however I am unsure as to 
>> whether this is correct behavior, or just an expected behavior 
>> of shadowing.
>
> Yes, it is correct behavior, though it does trip a lot of 
> people up.
>
> Each variable set in a class declaration is independent. 
> Lookups go for the first one they see up a chain from the 
> static type.
>
> Inside the override foo, it looks up and sees B.boolean. But 
> outside, you cased to A, so it can only see A.boolean.
>
> Object-oriented pattern here is typically to keep your member 
> vars private and read/write through accessor methods instead, 
> which can be virtual and thus be overridden in child classes as 
> needed.

Ah, okay. Thanks for the clarification.