Alias this and inheritance
ag0aep6g
anonymous at example.com
Sun Nov 5 10:38:45 UTC 2017
On Sunday, 5 November 2017 at 07:07:43 UTC, Aurelien Fredouelle
wrote:
> struct S { }
>
> class A
> {
> S s;
> alias s this;
> }
>
> class B : A
> {
> }
>
> void main()
> {
> A asA = new B;
> B asB = cast(B)asA;
> }
>
> I would expect the last line to successfully cast the B
> instance I created back into type B, however this seems to be
> preempted by the alias this:
>
> Error: cannot cast expression asA.s of type S to app.B
>
> Is there a way to force this cast to operate on the object of
> type A instead of automatically using A.s?
Known issue: https://issues.dlang.org/show_bug.cgi?id=6777
You can work around by casting to Object first:
B asB = cast(B) cast(Object) asA;
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