interface I {
	final int foo(I other, int a, int b) {
		return other.foo(a,b) + a*b;
	}
	int foo(int a, int b);
}

class A : I {
	int foo(int a, int b) {
		return a*b;
	}
}

void main() {
	A a = new A;

	a.foo(5,5);
	a.I.foo(a, 5,5);
	a.foo(a, 5,5); //line 22
}
---------
$ rdmd interface_final_test
interface_final_test.d(22): Error: function interface_final_test.A.foo (int a, int b) is not callable using argument types (A,int,int)
interface_final_test.d(22): Error: expected 2 arguments, not 3 for non-variadic function type int(int a, int b)
---------


Why do I need to write a.I.foo instead of a.foo to call the final method of the interface ?

Thank you, Joshua

21.02.2012 14:46, Joshua Reusch пишет:
> interface I {
> final int foo(I other, int a, int b) {
> return other.foo(a,b) + a*b;
> }
> int foo(int a, int b);
> }
>
> class A : I {
> int foo(int a, int b) {
> return a*b;
> }
> }
>
> void main() {
> A a = new A;
>
> a.foo(5,5);
> a.I.foo(a, 5,5);
> a.foo(a, 5,5); //line 22
> }
> ---------
> $ rdmd interface_final_test
> interface_final_test.d(22): Error: function interface_final_test.A.foo (int a, int b) is not callable using argument types (A,int,int)
> interface_final_test.d(22): Error: expected 2 arguments, not 3 for non-variadic function type int(int a, int b)
> ---------
>
>
> Why do I need to write a.I.foo instead of a.foo to call the final method of the interface ?
>
> Thank you, Joshua
>
>

I can't comment on the behaviour, but you may find this workaround useful:

class A : I {
alias I.foo foo;
int foo(int a, int b) {
return a*b;
}
}

On 2012-02-21 14:15, Mantis wrote:
> 21.02.2012 14:46, Joshua Reusch пишет:
>> interface I {
>> final int foo(I other, int a, int b) {
>> return other.foo(a,b) + a*b;
>> }
>> int foo(int a, int b);
>> }
>>
>> class A : I {
>> int foo(int a, int b) {
>> return a*b;
>> }
>> }
>>
>> void main() {
>> A a = new A;
>>
>> a.foo(5,5);
>> a.I.foo(a, 5,5);
>> a.foo(a, 5,5); //line 22
>> }
>> ---------
>> $ rdmd interface_final_test
>> interface_final_test.d(22): Error: function interface_final_test.A.foo
>> (int a, int b) is not callable using argument types (A,int,int)
>> interface_final_test.d(22): Error: expected 2 arguments, not 3 for
>> non-variadic function type int(int a, int b)
>> ---------
>>
>>
>> Why do I need to write a.I.foo instead of a.foo to call the final
>> method of the interface ?
>>
>> Thank you, Joshua
>>
>>
>
> I can't comment on the behaviour, but you may find this workaround useful:
>
> class A : I {
> alias I.foo foo;
> int foo(int a, int b) {
> return a*b;
> }
> }

It's because the base class and the subclass use different overload sets, or something like that.

-- 
/Jacob Carlborg

On 02/21/2012 04:46 AM, Joshua Reusch wrote:
> interface I {
> final int foo(I other, int a, int b) {
> return other.foo(a,b) + a*b;
> }
> int foo(int a, int b);
> }
>
> class A : I {
> int foo(int a, int b) {
> return a*b;
> }
> }
>
> void main() {
> A a = new A;
>
> a.foo(5,5);
> a.I.foo(a, 5,5);
> a.foo(a, 5,5); //line 22
> }
> ---------
> $ rdmd interface_final_test
> interface_final_test.d(22): Error: function interface_final_test.A.foo
> (int a, int b) is not callable using argument types (A,int,int)
> interface_final_test.d(22): Error: expected 2 arguments, not 3 for
> non-variadic function type int(int a, int b)
> ---------
>
>
> Why do I need to write a.I.foo instead of a.foo to call the final method
> of the interface ?
>
> Thank you, Joshua
>

Are you using 2.058? If so, this may be a bad interaction with the newly-added UFCS feature, which I haven't seen working yet. :)

The reason that I think so is that when the 'I other' is moved to a parameter location other than the first one, it works:

interface I {
    final int foo(int a, I other, int b) {// <- second parameter
        return other.foo(a,b) + a*b;
    }
    int foo(int a, int b);
}

class A : I {
    int foo(int a, int b) {
        return a*b;
    }
}

void main() {
    A a = new A;

    a.foo(5,5);
    a.I.foo(5, a, 5);
    a.foo(5,5); //line 22
}

I would say this warrants a bug report. The original code should have worked too.

Ali

On 02/21/2012 09:58 AM, Ali Çehreli wrote:

> The reason that I think so is that when the 'I other' is moved to a
> parameter location other than the first one, it works:

No, it doesn't work. Sorry for the noise.

Ali