4647 – [tdpl] Cannot explicitly call final interface method, ambiguous calls allowed

Code on 2.048:
import std.stdio;
interface Timer
{
 final void run() { writeln("Timer.run()"); };
}
interface Application
{
 final void run() { writeln("Application.run()"); };
}
class TimedApp : Timer, Application
{
}
import std.stdio;
void main()
{
 auto app = new TimedApp;
 app.Timer.run(); // error, no Timer property
 app.Application.run(); // error, no Application property
 app.run(); // This would call Timer.run() if the two calls
 // above were commented out
}
The comments state what happens.
Note that if I changed the order of the TimedApp signature like so:
class TimedApp : Application, Timer
then the Application's run() method would be called instead of Timer's in the app.run() call.

Comment from Lukasz Wrzosek
>This:
> app.Timer.run(); // error, no Timer property
> app.Application.run(); // error, no Application property
>
>probably should be:
> (cast(Timer)app).run();
> (cast(Application)app).run();
>
>But app.run() is still ambiguous - should not compile.
I don't see why I would need a cast. I can explicitly call methods from inherited classes, like so:
import std.stdio;
class Base
{
 void test() { writeln("Base.test()"); };
}
class Derived : Base
{
 override void test() { writeln("Derived.test()");}
}
class SecondDerived : Derived
{
}
void main()
{
 auto var = new SecondDerived;
 var.Base.test(); // calls Base.test()
 var.Derived.test(); // calls Derived.test()
}
So why shouldn't I be able to do the same with interfaces? TDPL allows it, I think it should be allowed in DMD.

I don't have TDPL in front of me right now, but I, too, seem to remember that this should be allowed. Raising the priority of this.

*** Issue 6680 has been marked as a duplicate of this issue. ***

Patch for app.Timer.run() / app.Application.run():
https://github.com/D-Programming-Language/dmd/pull/578
----
(In reply to comment #0)
> Note that if I changed the order of the TimedApp signature like so:
> 
> class TimedApp : Application, Timer
> 
> then the Application's run() method would be called instead of Timer's in the
> app.run() call.
I think the behavior is correct, because name lookup is depth-first.
Then app.run() depends on the order of derived bases.

https://github.com/D-Programming-Language/dmd/commit/4d9f2e7fd86fcdf9cbfec5c9bbad304ed125132d
https://github.com/D-Programming-Language/dmd/commit/d0fcaa80b468c455ce4b25a7af6c61fcaf749ee1 

*** Issue 3759 has been marked as a duplicate of this issue. ***