The work done in the Gradle project by Orchard, et al has been consistently good. I think a really solid progression from this paper is to take the same approach and combine it with the type system feature in ‘A Flexible Type System for Fearless Concurrency’ (Milano,etal 2022) [1]. The thrust of said paper is to utilize a coarser grain for ‘objects’ than what Rust promotes, which allows for much simpler implementations of common data structures (the paper uses a doubly linked, circular list as a well worked out example). Combining Milano’s approach to the scale at which ‘ownership’ is applied with the graded modality work from Orchard, et al would produce a very promising type system, with less syntactic noise from annotations, and still allow for a sliding scale of fineness in ownership semantics.