DIP66 - Multiple alias this

[via Digitalmars-d]

On Sunday, 12 October 2014 at 04:31:22 UTC, Walter Bright wrote:
> On 10/11/2014 7:23 AM, IgorStepanov wrote:
>> class A
>> {
>>    int i;
>>    alias i this;
>> }
>>
>> class B
>> {
>>    int i;
>>    alias i this;
>> }
>>
>> class C
>> {
>>    A a;
>>    B b;
>>    alias a this;
>>    alias b this;
>> }
>>
>> void foo(T)(T arg) if(is(T : int))
>> {
>>    ...
>> }
>>
>> foo(C()); //Should it pass or not?
>
> There's a rule with imports that if the same symbol is 
> reachable via multiple paths through the imports, that it is 
> not an ambiguity error. Here, the same type is reachable 
> through multiple alias this paths, so by analogy it shouldn't 
> be an error.

It's the same type, but different symbols; actual accesses would 
be ambiguous. `is(T : int)` shouldn't evaluate to true if `int a 
= T.init;` would fail.