DIP66 - Multiple alias this

[Walter Bright via Digitalmars-d]

On 10/10/2014 3:46 PM, Timon Gehr wrote:
> On 10/11/2014 12:29 AM, Walter Bright wrote:
>> On 10/10/2014 3:06 PM, Timon Gehr wrote:
>>> On 10/10/2014 11:25 PM, Walter Bright wrote:
>>>>
>>>> Essentially, the rules for multiple alias this should be the same as for
>>>> multiple imports and multiple mixin templates. These rules work, and the
>>>> consistency will be expected.
>>>
>>> Agreed. Do you suggest to overload alias this against imports and
>>> mixin templates?
>>
>> I hadn't thought of that (thanks for bringing it up). My first thought
>> is no. Alias this gets searched after those do, because it comes into
>> play only when the symbol isn't resolved in the scope.
>
> This allows for symbol hijacking (this is also the current behaviour):
>
> // ---
>
> module m;
> import std.stdio;
> // void foo(int x){ writeln("hi from m"); } // uncomment to hijack
>
> // ---
>
> module main;
> import std.stdio;
>
> struct T{
>      import m;
>      alias s this;
>      S s;
> }
>
>
> struct S{
>      void foo(int x){ writeln("hi from S"); }
> }
>
> void main(){
>      T t;
>      t.foo(1);
> }

Hmm. Good point. The alias this should be done before imports.