There are several scenarios when you will need to override or patch upstream dependencies. Like testing a bugfix of your crates before pushing to crates.io, a non-working upstream crate has a new feature or a bug fix on the master branch of its git repository that you'd want to try, etc. In these cases, the [patch] section of Cargo.toml might be useful.

Since 1.64.0, Cargo now supports workspace inheritance, so you can avoid duplicating similar field values between crates while working within a workspace. Workspace inheritance can include things like shared version numbers, repository URLs, or rust-version.

In Rust, the question mark (?) operator is used as an alternate error propagation method for functions that yield Result or Option types. The ? operator is a shortcut that minimizes the amount of code required in a function to quickly return Err or None from the types Result<T, Err>, or Option.