According to TDPL the whole object destructor chain is called up to the top of the hyerarchy. This D2 program compiles and runs with DMD 2.048 with no errors:


import std.c.stdio: puts;
class Base {
     private final ~this() { puts("Base.~this"); }
}
class Derived : Base {
    private final ~this() { puts("Derived.~this"); }
}
void main() {
    new Derived();
}


Output:

Derived.~this
Base.~this


Are the 'private final' attributes used here correct?
See also:  http://d.puremagic.com/issues/show_bug.cgi?id=3934

Bye,
bearophile

bearophile <bearophileHUGS@lycos.com> wrote:

> According to TDPL the whole object destructor chain is called up to the top of the hyerarchy.
> This D2 program compiles and runs with DMD 2.048 with no errors:
>
>
> import std.c.stdio: puts;
> class Base {
>      private final ~this() { puts("Base.~this"); }
> }
> class Derived : Base {
>     private final ~this() { puts("Derived.~this"); }
> }
> void main() {
>     new Derived();
> }
>
>
> Output:
>
> Derived.~this
> Base.~this
>
>
> Are the 'private final' attributes used here correct?
> See also:  http://d.puremagic.com/issues/show_bug.cgi?id=3934

A destructor is always final, and private destructors make no sense,
so I would say the attributes should not be there.

-- 
Simen

Simen kjaeraas:
> A destructor is always final, and private destructors make no sense, so I would say the attributes should not be there.

Thank you for your answer, I have added the test case to bug 3934

Bye,
bearophile

On Thursday, August 19, 2010 08:23:42 Simen kjaeraas wrote:
> A destructor is always final, and private destructors make no sense, so I would say the attributes should not be there.

Actually, I could see private destructors making at least some sense. Obviously, the runtime needs to be able to call them, but I could see someone wanting to make it so that a destructor could not be explicitly called by the programmer. I'm not sure that that's ultimately all that useful, but I could see private destructors working that way.

- Jonathan M Davis