Bug? NVI functions can't call normal interface functions?

[Johannes Pfau]

Am Tue, 19 Mar 2013 17:51:52 -0400
schrieb "Steven Schveighoffer" <schveiguy at yahoo.com>:

> On Sun, 17 Mar 2013 09:59:03 -0400, Maxim Fomin
> <maxim at maxim-fomin.ru> wrote:
> 
> > Actually it was http://d.puremagic.com/issues/show_bug.cgi?id=4589
> 
> I don't think this is the same problem.
> 
> I modified the program a bit:
> 
> import core.stdc.stdio;
> interface Timer
> {
>      final int run() { printf("Timer.run(), this=%x\n",
> cast(void*)this); fun(); return 1;}
>      int fun();
> }
> interface Application
> {
>      final int run() { printf("Application.run(), this=%x\n",
> cast(void *)this); fun(); return 2; };
>      int fun();
> }
> 
> class TimedApp : Timer, Application
> {
>      int fun()
>      {
>          printf("TimedApp.fun(), this=%x\n", cast(void*)this);
>          return 0;
>      }
> }
> 
> void main()
> {
>      auto app = new TimedApp;
>      (cast(Application)app).run();
>      (cast(Timer)app).run();
>      app.Application.run();
>      app.Timer.run();
> }
> 
> New output:
> 
> Application.run(), this=10007ff8
> TimedApp.fun(), this=10007fe0
> Timer.run(), this=10007ff0
> TimedApp.fun(), this=10007fe0
> Application.run(), this=10007fe0
> Timer.run(), this=10007fe0
> 
> Note that Application.run() is given the interface pointer 10007ff8,  
> whereas the *true* object pointer is 10007fe0.  This is normal and  
> expected.
> 
> However, in the *last* call to Application.run (and Timer.run), it's
> given the pointer 10007fe0, the true object pointer.  This gives it
> the completely WRONG vtable to use for calling fun.  I think this is
> different than the bug I posted.  It may be related, I don't know.
> 
> If this bug is not already reported, it should be.
> 
> -Steve

I'll report it soon and I already have a bug fix. (The compiler indeed
always passed the object pointer. This is valid for base classes, but
not for interfaces. Adding an isInterface check + CastExpression solves
this issue)