when should ranges be static

[Inkrementator]

On Saturday, 15 February 2025 at 11:47:58 UTC, Inkrementator 
wrote:
> Wrapping foo in another delegate seems to at least compile.

Same as splitting out the struct. I don't understand why a struct 
outside of a function gets treated differently than a static 
struct.

```
auto split(alias F,R)(R r){
	return splitter!(F,R)(r);
}

private struct splitter(alias F, R){
	R r;
	auto front()=>r.takeuntil(r.findnext!F);
	void popFront(){r=r.findnext!F;}
	bool empty()=>r.empty;
}
```