Dlang Polymorphism doesn't work as expected.

[Enjoys Math]

On Sunday, 4 September 2022 at 17:36:24 UTC, Enjoys Math wrote:
> I have the following MWE:
>
> ```
> import std.exception;
> import std.stdio;
>
> abstract class B
> {
>    B opCall() {
>       throw new Exception("NotImplemented");
>    }
> }
>
> class A : B
> {
>    override B opCall() {
>       return new A();
>    }
> }
>
> int main() {
>    B a = new A();
>    a();
>    readln();
>    return 0;
> }
>
> ```
>
> But B.opCall() gets called!   I thought polymorphism was cool 
> until now....
>
> How can I get this to work the way I expected it to?  Would an 
> abstract method in base do it?

Okay... now the MWE works as I expected polymorphism to work, but 
my complicated library is not doing it right...

:\