Came to say the same thing. Rust requires explicit annotation of usage semantics. This information somehow has to get conveyed to the compiler and runtime. So the 'ergonomic' issues are fundmantal.
I think from a PLT perspective, the interesting question is 'can the problems Rust is supposed to solve be resolved in a simpler (but radically different) conceptual model'? We started off originally with a spatial conceptual model -- stack, heap, scope -- that mapped lifecycle semantics to spaces and transitions between spaces. Concurrent programming stressed out that model and we're here with explicit mapping of semantics by the programmer. I've been wondering lately whether a new spatial approach can yet again simplify matters.
I think from a PLT perspective, the interesting question is 'can the problems Rust is supposed to solve be resolved in a simpler (but radically different) conceptual model'? We started off originally with a spatial conceptual model -- stack, heap, scope -- that mapped lifecycle semantics to spaces and transitions between spaces. Concurrent programming stressed out that model and we're here with explicit mapping of semantics by the programmer. I've been wondering lately whether a new spatial approach can yet again simplify matters.