Tagging of arguments ref/out, or just out

[Don]

bearophile wrote:
> Max Klyga:
>  
>> So this feature has to be either mandatory or not. Making it optional 
>> leads to confusion as Jonathan mentioned.
> 
> On this, what I have suggested it not the same thing that the original proposal says. In the original proposal the "ref" and "out" are optional. In my alternative proposal if you compile with "-w" you are sure that the compiler will ask you "out" at the calling point too.

Please bury forever the idea that "mandatory when compiled with -w" has 
any practical difference from "mandatory".