Inherent code performance advantages of D over C?

[Timon Gehr]

On 12/15/2013 02:20 AM, Walter Bright wrote:
> On 12/14/2013 4:36 PM, Timon Gehr wrote:
>> I cannot cast data from my own storage allocator to immutable because the
>> behaviour will be undefined.
>>
>> http://dlang.org/const3.html
>>
>> Is this a documentation bug? What should be the actual rules?
>
> It means it's up to you to ensure it is correct.

Undefined behaviour is a term with a precise meaning. That site says 
that casting a reference to immutable while there are still live mutable 
references to memory reachable by that reference leads to undefined 
behaviour. It is not possible to 'ensure it is correct'.