What's missing to make D2 feature complete?

[via Digitalmars-d]

On Monday, 22 December 2014 at 21:52:12 UTC, ketmar via 
Digitalmars-d wrote:
>> Thanks, I forgot that one. Immutable values by default is 
>> indeed an important improvement. All by-value parameters to 
>> functions should be immutable, period.
>
> but why? O_O

Because it is safer in long functions where you might miss a 
modification of the input parameter when editing an existing 
function, and copying from immutable to mutable is free if the 
parameter is left alone after the copy.