Let's get the semantic around closure fixed.

[deadalnix]

On Friday, 28 May 2021 at 02:47:41 UTC, Adam D. Ruppe wrote:
> On Friday, 28 May 2021 at 02:41:27 UTC, Q. Schroll wrote:
>> I was a little surprised that it needs the GC in the first 
>> place. It's a template parameter after all.
>
> It isn't the lambda that allocates per se, it is the 
> `MapResult` struct that cannot necessarily be scope since it 
> doesn't know if the range will be stored or returned or 
> whatever.
>
> Though perhaps if the returned map result inherited the 
> lifetime of the captured variables it could work, just that 
> gets complicated.

I suspect the compiler should be able to see through it after a 
few rounds of inlining.

If there are so many layers that it doesn't, I suspect one 
allocation isn't going to be your bottleneck.