April 03, 2023

Hi, am I missing something or is this a bug?
I'm trying to load a C++ DLL (a vst3). and most of it works perfectly, but i've got a case where the order of two mixins suddenly matters, but they mixin override functions.
looks like somehow the vtable gets screwed up.
code is minified to explain whats going on, i can provide a complete compilabe project if nessecary.
am i correct that this is a bug and the order of the two mixins shouldn't matter?

extern (C++)
class HostMessage : IMessage
  // somehow the order of the two mixins matters
  mixin QUERY_INTERFACE!(FUnknown, IMessage);

mixin template IMPLEMENT_REFCOUNT() {
  override uint addRef()  { return 1; }
  override uint release() { return 1; }

mixin template QUERY_INTERFACE(Interfaces...) {
  override tresult queryInterface (ref const TUID _iid, void** obj) { return 1; }

interface IMessage : FUnknown
// @nogc:
	/** Returns the message ID (for example "TextMessage"). */
	FIDString getMessageID();

	/** Sets a message ID (for example "TextMessage"). */
	void setMessageID(FIDString id /*in*/);

	/** Returns the attribute list associated to the message. */
	IAttributeList getAttributes();

    __gshared immutable TUID iid = INLINE_UID(0x936F033B, 0xC6C047DB, 0xBB0882F8, 0x13C1E613);

interface FUnknown : IUnknown {
    __gshared immutable TUID iid = INLINE_UID(0x00000000, 0x00000000, 0xC0000000, 0x00000046);

interface IUnknown {
    tresult queryInterface(ref const(TUID) _iid, void** obj);
    uint addRef();
    uint release();
April 03, 2023

On Monday, 3 April 2023 at 11:24:16 UTC, Zoadian wrote:

ok, i think i found the real problem: somehow the compiler treats my interface IUnknown specially. i've filed a bug report: https://issues.dlang.org/show_bug.cgi?id=23819




and this leads to to compiler messing up my code without any warning.