diff --git a/.gitattributes b/.gitattributes
index e796dc7cab..6fe4287105 100644
--- a/.gitattributes
+++ b/.gitattributes
@@ -11819,6 +11819,7 @@ tests/webtbs/tw1909.pp svneol=native#text/plain
 tests/webtbs/tw1910.pp svneol=native#text/plain
 tests/webtbs/tw1915.pp svneol=native#text/plain
 tests/webtbs/tw1917.pp svneol=native#text/plain
+tests/webtbs/tw19180.pp svneol=native#text/plain
 tests/webtbs/tw19182.pp svneol=native#text/plain
 tests/webtbs/tw1920.pp svneol=native#text/plain
 tests/webtbs/tw19201.pp svneol=native#text/pascal
diff --git a/tests/webtbs/tw19180.pp b/tests/webtbs/tw19180.pp
new file mode 100644
index 0000000000..d42e7d2819
--- /dev/null
+++ b/tests/webtbs/tw19180.pp
@@ -0,0 +1,127 @@
+program IntfDelegationCrash;
+
+{$mode objfpc}{$H+}
+
+
+type
+
+  IGMGetFileName = interface(IUnknown)
+    ['{D3ECCB42-A563-4cc4-B375-79931031ECBA}']
+    function GetFileName: String; stdcall;
+    property FileName: String read GetFileName;
+  end;
+
+
+  IGMGetHandle = interface(IUnknown)
+    ['{5BB45961-15A9-11d5-A5E4-00E0987755DD}']
+    function GetHandle: THandle; stdcall;
+    property Handle: THandle read GetHandle;
+  end;
+
+
+  { TImplementor }
+
+  TImplementor = class(TObject, IGMGetFileName, IGMGetHandle)
+   protected
+    FController: Tobject;
+
+   public
+    constructor Create(const AController: TObject);
+
+    function QueryInterface(constref IID: TGUID; out Intf): HResult; virtual; {$ifdef window}stdcall{$else}cdecl{$endif};
+    function _AddRef: LongInt; virtual; {$ifdef windows}stdcall{$else}cdecl{$endif};
+    function _Release: LongInt; virtual; {$ifdef windows}stdcall{$else}cdecl{$endif};
+
+    function GetHandle: THandle; stdcall;
+    function GetFileName: String; stdcall;
+  end;
+
+  { TDelegator }
+
+  TDelegator = class(TInterfacedObject, IGMGetFileName) // IGMGetHandle
+   protected
+    FImplementor: TImplementor;
+    FGetFileName: IGMGetFileName;
+
+   public
+    constructor Create;
+    destructor Destroy;
+
+    //
+    // This crashes
+    //
+    property Implementor: TImplementor read FImplementor implements IGMGetFileName;
+
+    //
+    // This works
+    //
+    //property Implementor: IGMGetFileName read FGetFileName implements IGMGetFileName;
+
+    //
+    // This is what i really need
+    //
+    //property Implementor: TImplementor read FImplementor implements IGMGetFileName, IGMGetHandle;
+  end;
+
+
+{ TImplementor }
+
+constructor TImplementor.Create(const AController: TObject);
+begin
+  FController := AController;
+end;
+
+function TImplementor.QueryInterface(constref IID: TGUID; out Intf): HResult; {$ifdef windows}stdcall{$else}cdecl{$endif};
+var PIUnkController: IUnknown;
+begin
+  if GetInterface(IID, Intf) then Result := S_OK else
+   if (FController <> nil) and FController.GetInterface(IUnknown, PIUnkController) then
+    Result := PIUnkController.QueryInterface(IID, Intf) else Result := E_NOINTERFACE;
+end;
+
+function TImplementor._AddRef: LongInt; {$ifdef windows}stdcall{$else}cdecl{$endif};
+var PIUnkController: IUnknown;
+begin
+  if (FController <> nil) and FController.GetInterface(IUnknown, PIUnkController) then
+   Result := PIUnkController._AddRef
+end;
+
+function TImplementor._Release: LongInt; {$ifdef windows}stdcall{$else}cdecl{$endif};
+var PIUnkController: IUnknown;
+begin
+  if (FController <> nil) and FController.GetInterface(IUnknown, PIUnkController) then
+   Result := PIUnkController._Release
+end;
+
+function TImplementor.GetHandle: THandle; stdcall;
+begin
+  Result := 0;
+end;
+
+function TImplementor.GetFileName: String; stdcall;
+begin
+  Result := '';
+end;
+
+
+{ TDelegator }
+
+constructor TDelegator.Create;
+begin
+  FImplementor := TImplementor.Create(Self);
+  FGetFileName := FImplementor;
+end;
+
+destructor TDelegator.Destroy;
+begin
+  FImplementor.Free;;
+end;
+
+
+var PIUnk: IUnknown; PIGetFileNAme: IGMGetFileName;
+begin
+  PIUnk := TDelegator.Create;
+  PIUnk.QueryInterface(IGMGetFileName, PIGetFileNAme);
+end.
+
+