DIP53 and DIP49 (ver2) - New definitions for qualified constructors and postblits

[ilya-stromberg]

On Wednesday, 18 December 2013 at 19:10:07 UTC, Joseph Rushton 
Wakeling wrote:
> Well, quite :-)  I'm not complaining about the issues here, I'm 
> suggesting that inventing an extra keyword for the cases 
> discussed in these DIPs is not necessary, because the analogy 
> and connection with existing use of const/immutable is valuable.

Sorry if I miss something, but I don't understand this analogy.

`const` means that original type can be `mutable` or `immutable`, 
so both `mutable` and `immutable` types can be implicitly 
converted to the `const` type.

If I understand DIP correctly, unique postblit/constructor 
returns `unique` type that can be implicitly converted to the all 
of `mutable`, `immutable` and `const` types. So, this behavior is 
the opposite of current `const` behavior.

So, where is analogy here?

BTW, it looks like the DIP mix `const` and `unique` semantic. 
It's different things, but they are in the same section.