This is great in theory but in reality no such distinction exists. For example, is trying to read a missing file a failure of the code, or a failure of the user? It could easily be either, the developer hardcoded the file path wrong during development, or the user selected a wrong path in a CLI, ... the distinction between errors and exceptions must made by the call site, not the definition site. The code calling readFile() knows whether the error is recoverable or not. readFile() itself does not, so the same mechanism should be used for both errors and exceptions.
All this was figured out decades ago, that's why exception systems were invented, but language designers keep making the same mistake over and over again in an effort to simplify the unsimplifiable.
All this was figured out decades ago, that's why exception systems were invented, but language designers keep making the same mistake over and over again in an effort to simplify the unsimplifiable.