DIP66 - Multiple alias this

[Timon Gehr via Digitalmars-d]

On 10/11/2014 12:07 AM, IgorStepanov wrote:
> On Friday, 10 October 2014 at 21:25:17 UTC, Walter Bright wrote:
>>
>> If 'a' and 'b' both contain overloads for function foo, then it should
>> behave like imports do (which is a bit complex).
>
> Hmm. Now it works as I wrote it DIP pseudo-code:

The pseudo-code doesn't actually specify that the arguments the 
identifier is being called with are considered at all.

> struct A
> {
>      void foo(string);
>      void foo(int);
> }
>
> struct B
> {
>      void foo(double);
> }
>
> struct C
> {
>      A a;
>      B b;
>      alias a this;
>      alias b this;
> }
>
> C.foo("test"); //found only one acceptable foo: C.a.foo(string)
> C.foo(5);      //1. Check a: found C.a.foo(int);
>                 //2. Check b: found C.b.foo(double);
>                 //3. Raise error: C.a.foo(int) vs C.b.foo(double) conflict
> C.foo(5.0);    //found only one acceptable foo: C.b.foo(double)
>
> Is it Ok?
> ...

That is the right behaviour. What happens in this case:

struct A{
     void foo(int);
     void foo(double);
}

struct B
     void foo(string);
}

... // (struct C and calls as yours)



Is it correct that the DIP makes imports at aggregate scope shadow alias 
this lookups?