Deprecating this(this)

[Andrei Alexandrescu]

On 04/03/2018 10:21 AM, ag0aep6g wrote:
> On Tuesday, 3 April 2018 at 12:52:00 UTC, Andrei Alexandrescu wrote:
>> On 04/03/2018 07:36 AM, ag0aep6g wrote:
>>> For constructors, we say that the first assignment is actually 
>>> initialization. The compiler might or might not put the .init value 
>>> down before calling the constructor. Doesn't matter, because the 
>>> constructor will overwrite it anyway, and nothing of value is lost.
>>
>> What happens in fact is you are guaranteed the .init value is there. 
>> Much later, well after semantic checking, the backend optimizer 
>> removes dead assignments on primitive data.
> 
> So constructors, including const/immutable ones, basically work the same 
> as postblit already? You get an object pre-filled with some values, and 
> then you can "initialize" the fields some more if you want.

Well... not really. This is because .init is really an inert state - 
null indirections, no state allocated etc. Makes typechecking easy, and 
calling constructor on top of .init is what happens already. In 
contrast, the postblit situash is very different - the fields already 
contain "interesting" data, allocated resources etc. Calling a 
constructor on top of that is not defined.