In my application I have my own error type: an enum that has several variants, one of which isDb(tokio_postgres::Error). When showing my error, in the case of a Postgres error, I was basically doing this:format!("DB error: {}", error). This is rather common: error types wrapping other errors often print some kind of prefix signalling the kind of error.

The problem is thattokio_postgres::Error itself is already printingdb error insome situation.

https://github.com/sfackler/rust-postgres/blob/d45461614aca87022c17a2cc26b22325bf161fa5/tokio-postgres/src/error/mod.rs#L377-L403

That means my error output usually is something likeDB error: db error: .... That's not optimal of course. But I also can't really omit my own prefix, since in other cases, Postgres' error will not printdb error as prefix.

I would have created a PR, but I lack the knowledge what theKind::Db represents exactly and when it is used. Is it just a "generic" kind? Would it be possible to change the"db error" string to something else? Or at least omit it if there is a cause?