While QFuture is generally designed to support move-only types, using unwrap() on a (nested) future holding a move-only type fails to compile. The code inside QFuture::unwrap() is quite clear in its expectation of the result type copyability:

            // ...

            nestedFuture.then([promise] (const QFuture<NestedType> &nested) mutable { // <- passing `nested` by const&

                // ...

                {

                    if constexpr (!std::is_void_v<NestedType>)
                        promise.reportResults(nested.results()); // <- calling results() that copies the stored QList

                                      }

Though QFuture::takeResults() to move the entire underlying QList might be too much to add (might it?), at least unwrap() could make a new QList and std::move() each result in that new list if it detects move-only result type.