Let's get the semantic around closure fixed.

[Ola Fosheim Grostad]

On Thursday, 20 May 2021 at 11:40:24 UTC, Ola Fosheim Grostad 
wrote:
> The more I think about this the more I dislike separate 
> compilation (to asm, to IR is ok). If you ditch that maybe you 
> could use static analysis and store the closure in the delegate 
> object.

In my experience, lamdas often capture few symbols, so it is a 
bit silly to heap allocate 16 bytes... But std::function is not a 
good solution as its internal buffer is fixed, which is wasteful.