Copy Constructor DIP and implementation

[shfit]

On Monday, 17 September 2018 at 19:10:27 UTC, Jonathan M Davis 
wrote:

> We're talking about introducing an attribute that should be 
> unnecessary, which will be annoying to use, and which will be 
> error-prone given the bugs that you'll get if you forget to 
> mark your copy constructor with it. And it's all to avoid 
> breaking a theoretical piece of code that I would think that we 
> could all agree is extremely rare if it exists in any real D 
> code base at all. Simply using a transitional compiler switch 
> like we have with other DIPs would make _way_ more sense than 
> burdening the language with an unnecessary attribute that's 
> just going to make it easier to write buggy code. This is 
> clearly a case of making the language worse long term in order 
> to avoid a theoretical problem in the short term.
>
> - Jonathan M Davis

Completely agree.