Understanding RefCounted

[JG]

Reading the documentation on RefCounted I get the impression that 
the following can lead to memory errors. Could someone explain 
exactly how that could happen? I suppose that problem would be 
the call something to do with front?


```
private struct RefCountedRangeReturnType(R)
{
     import std.typecons : RefCounted;
     private RefCounted!R r;
     auto empty() { return r.refCountedPayload.empty; }
     auto front() { return r.refCountedPayload.front; }
     void popFront() { r.refCountedPayload.popFront; }
     auto save() { return 
typeof(this)(RefCounted!R(r.refCountedPayload.save)); }
}

auto refCountedRange(R)(R r)
{
     import std.typecons : RefCounted;
     return  RefCountedRangeReturnType!R(RefCounted!R(r));
}
```