Whether it should be an error or not, the compiler should never crash, so thank you! I think you're missing some of your example, though: what's T?

Comment by Samuel Huang (JIRA)

T is of type(s) Any, the implementation is a reloadable, paged collection for tableviews/collectionviews

Since coming across this issue, I've now updated the method signature to to:

    var doLoad: ((((_ items: [T]) -> Void)?) -> Void)?
    func load() {
        if state == .empty || state == .loaded {
            state = .loading
            doLoad? { items in
                self.update(items: items)
            }
        }
    }

and now it works fine...

We'd still like to track down the original failure, but we need a self-contained test case to do that. Just this bit of code isn't enough.