Rvalue references - The resolution

[deadalnix]

On Saturday, 4 May 2013 at 21:57:14 UTC, deadalnix wrote:
> On Saturday, 4 May 2013 at 21:48:25 UTC, Walter Bright wrote:
>> On 5/4/2013 2:22 PM, deadalnix wrote:
>>> I still think this is inferior to Rust's solution and like to 
>>> see ref as a
>>> equivalent of the Rust burrowed pointer. It achieve the same 
>>> safety at compile
>>> time instead at runtime, and incurs no extra complexity 
>>> except in some very rare
>>> cases (when you have a function taking several arguments by 
>>> ref and returning
>>> also by ref and the lifetime of the returned ref isn't the 
>>> union of the lifetime
>>> of the ref parameters - a very specific case).
>>
>> As you say, D ref's are analogous to Rust's borrowed pointers, 
>> and for the escaping ref problem, Rust requires additional 
>> annotations (much like the 'scope ref' proposal).
>>
>> http://static.rust-lang.org/doc/tutorial-borrowed-ptr.html#returning-borrowed-pointers
>>
>> The runtime check is because Andrei & I really didn't like 
>> requiring additional annotations.
>
> Where you miss the point, is that these annotations may be 
> omitted (and they are most of the time). When nothing is 
> specified, the lifetime of the returned reference is considered 
> to be the union of the lifetime of parameters lifetime, which 
> is what you want in 99% of cases.

Note : We may also choose the lack of explicit lifetime means 
runtime check as proposed, instead of being an error.