const(Class) is mangled as Class const* const

[Jerry via Digitalmars-d]

On Sunday, 26 March 2017 at 15:29:02 UTC, Jonathan M Davis wrote:
> Personally, I don't think that the fact that you can't use 
> const for head-const in D is really a loss, since it's almost 
> never what you want. Tail-const is _way_ more useful. But it is 
> true that by making D's const fully transitive, there are 
> variations of constness that C++ can do that D can't. immutable 
> pretty much forces that though, and it does simplify the 
> language.


There are quite a few things wrong with const, it's so bad phobos 
isn't even const-correct when it should be. In cmp() for example, 
if you pass a lambda that takes the parameters by reference. You 
will be modifying temporary values that cmp() created on the 
stack. These should be const, but then what if it is a pointer? 
It is a different situation and you don't really want const cause 
you are going to be modifying the correct struct (the one pointed 
to). It is just easier to not use const in D cause it makes your 
code more difficult to actually use. That's exactly what Phobos 
does, it ignores const for the most part because it is easier not 
to use it.