My understanding is that the latest RFCes touching that syntax (not sure if they're implemented) have it overloaded with traits, and I would guess/hope that it'

My understanding is that the latest RFCes touching that syntax (not sure if they're implemented) have it overloaded with traits, and I would guess/hope that it's possible to implement those traits in a way that is fallible (e.g. hypothetically 'impl BoxSyntax for Result<Box<T>, AllocationError>').