alias this doesn't work for properties.

[JS]

On Thursday, 1 August 2013 at 21:56:46 UTC, John Colvin wrote:
> On Thursday, 1 August 2013 at 20:42:08 UTC, JS wrote:
>> http://dpaste.dzfl.pl/0c923861
>>
>> class A
>> {
>>    double x;
>>    @property double X() { return x; }
>>    @property double X(double v) { return x = v; }
>>    alias X this;
>> }
>>
>> class B
>> {
>>    A a;
>>    @property A Y() { return a; }
>>    @property A Y(A v) { return a = v; }
>> }
>>
>>
>> void main()
>> {
>> 	B b = new B();
>> 	b.Y = 3;
>> }
>>
>> error not a property of b.Y
>>
>>
>>
>> adding refs to the returns of the getters allows the code to 
>> work but only getters are called(hence the need for refs).
>>
>> Please allow alias this to work with overloaded functions. 
>> (specifically properties, b.Y = 3; is not b.Y() = 3 but 
>> b.Y(3);)
>
> b.Y = 3 is rewritten as b.Y(3)
>
> You are asking for an "int" to be be implicitly convertible to 
> an "A", which isn't possible.

This is wrong because

(cast(A)b.Y) = 3;

works.

b.Y(3) should work because A is aliased to double.

One of the issues is

b.Y(3)

The setter of B is never called.

You are right that b.Y(3) does not accept an int(or double) BUT 
this is a bug in the compiler because it should since 3 can be 
assigned to it. It's just that the compiler isn't smart enough to 
see this because of the way it calculates the assignment.

b.Y = 3 should do the same as b.a = 3 which should be the same as 
b.a.x = 3.

If you think about what the code is actually doing you will see 
it should be possible.


http://dpaste.dzfl.pl/ac376ca0