> Ideally, each fallible function would have its own error enum to precisely capture its errors and handle them, but in practice it is too verbose and leads to using the less precise Error trait or one enum per module. The language could support this better: there are several initiatives and macros exploring this.

Definitely something I can agree with! Has your team explored any initatives / macros that seem promising? We're currently using the crate 'thiserror' but it's made our compilation times painful.