Re: Make sure lifetime of helper structs is less than owning struct

[Sebastiaan Koppe via Digitalmars-d-learn]

On Monday, 15 November 2021 at 15:56:57 UTC, WebFreak001 wrote:
is this currently possible or maybe possible with DIP1000?

Yes it is. But besides `-dip1000` and `@safe`, it requires the 
use of a pointer:

```D
@safe:

struct ByChunk {
    FileReader* r;
    void popFront() {}
}

struct FileReader {
    ByChunk byChunk() return scope {
        return ByChunk(&this);
    }
}

void main() {
        ByChunk helper;
        {
                auto file = FileReader();
    	helper = file.byChunk;  // Error: address of variable `file` 
assigned to `helper` with longer lifetime
        }
        helper.popFront;
}
```