How should class objects created in betterC be destroyed

[zoe]

On Monday, 6 November 2023 at 05:52:18 UTC, Imperatorn wrote:
> On Monday, 6 November 2023 at 05:30:02 UTC, zoe wrote:
>> I customized object.d in -betterc mode and created NEW 
>> templates, with modules I can seemingly create classes without 
>> extern(C++) mode, and type conversions in function calls seem 
>> to work fine. But when destroy doesn't find a way to call the 
>> __xtdor() method of the corresponding subclass, is there any 
>> way to execute __xtdor() correctly
>
> Do you have the implementation somewhere?

// app.d
module app;

import core.stdc.stdio;

interface L
{
   void interfaceTest();
}

class Base : L
{

   void interfaceTest()
   {
     puts("call base");
   }

   ~this()
   {
     puts("destory base");
   }
}

class Test : Base
{
   int i;
   int y;
   override void interfaceTest()
   {
     puts("call test");
   }

   ~this()
   {
     super.__xdtor();
     puts("destory test");
   }
}

public void test2(ref Base l)
{
   l.interfaceTest();
   l.destroy();
}

public void test()
{
   Base t = NEW!Test();
   test2(t);
}

extern (C) int main()
{
   test();
   return 0;
}

// object.d
module object;

import core.stdc.stdlib;
import core.stdc.string;
import core.stdc.stdio;

alias size_t = typeof(int.sizeof);
alias ptrdiff_t = typeof(cast(void*) 0 - cast(void*) 0);

alias sizediff_t = ptrdiff_t; // For backwards compatibility only.
// /**
//  * Bottom type.
//  * See $(DDSUBLINK spec/type, noreturn).
//  */
alias noreturn = typeof(*null);

alias hash_t = size_t; // For backwards compatibility only.
alias equals_t = bool; // For backwards compatibility only.

alias string = immutable(char)[];
alias wstring = immutable(wchar)[];
alias dstring = immutable(dchar)[];

T NEW(T, Args...)(auto ref Args args)
{
   enum tsize = __traits(classInstanceSize, T);
   T t = () @trusted {
     import core.stdc.stdlib;

     auto _t = cast(T) malloc(tsize);
     if (!_t)
       return null;
     import core.stdc.string : memcpy;

     memcpy(cast(void*) _t, __traits(initSymbol, T).ptr, tsize);
     return _t;
   }();
   if (!t)
     return null;
   t.__ctor(args);
   return t;
}

void destroy(T)(ref T instance)
{
   static if (__traits(hasMember, T, "__xdtor") &&
     __traits(isSame, T, __traits(parent, instance.__xdtor)))
     instance.__xdtor();
   () @trusted { import core.stdc.stdio;

   free(cast(void*) instance); }();
   instance = null;
}

class Object
{
   this()
   {
   }

   ~this()
   {
   }
}

//  dmd -betterC  .\app.d .\object.d  or  ldmd2 -betterC -m64   
.\app.d .\object.d
The destroy method does not find exactly what the subclass object 
should be