DIP: Tail call optimization

[Andrew Godfrey via Digitalmars-d-announce]

On Monday, 11 July 2016 at 10:25:36 UTC, Tofu Ninja wrote:
> On Sunday, 10 July 2016 at 13:15:38 UTC, Andrew Godfrey wrote:
>> Btw here's a thread from 2014 that touches on the idea of a 
>> "tailrec" annotation. At the time, Walter viewed the 
>> optimization as the compiler's business and not something he'd 
>> elevate to a language feature:
>>
>>
>> http://forum.dlang.org/post/lqp6pu$1kkv$1@digitalmars.com
>
> I find it odd that something like tail recursions that actually 
> makes certain things possible that wouldn't be otherwise is 
> seen as only an optimization, when things like inlining which 
> really is only an optimization is seen as important enough to 
> have a pragma.

I agree. Maybe Walter has reconsidered since then. He did also 
say, though, that he thinks D supports enough different 
programming styles already.

Would you be satisfied with a pragma? I'd intuited (but could be 
wrong) that the focus of your proposal was to get a compiler 
error if someone makes a change to a recursive function, that 
causes the compiler to be unable to apply the TCO optimization. 
If that is your focus, it has heavy implications and the feature 
can't just be a pragma.