[Issue 21762] object.destroy may silently fail depending on whether a member function is a template

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21762

--- Comment #2 from moonlightsentinel at disroot.org ---
This is probably caused by the forward reference of the destructors.

The non-templated next() instantiates A!C before the semantic of C is done and
before __xdtor is generated. A!C's destructor then instantiates destroy which
omits the dtor call because it's not yet available.

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