Merge pull request #190 from Manubi/patch-1

book/src/02_basic_calculator/08_overflow.md

@@ -69,12 +69,18 @@ You may be wondering—what is a profile setting? Let's get into that!
 A [**profile**](https://doc.rust-lang.org/cargo/reference/profiles.html) is a set of configuration options that can be
 used to customize the way Rust code is compiled.
 
-Cargo provides two built-in profiles: `dev` and `release`.\
+Cargo provides 4 built-in profiles: `dev`, `release`, `test`, and `bench`.\
 The `dev` profile is used every time you run `cargo build`, `cargo run` or `cargo test`. It's aimed at local
 development,
 therefore it sacrifices runtime performance in favor of faster compilation times and a better debugging experience.\
 The `release` profile, instead, is optimized for runtime performance but incurs longer compilation times. You need
 to explicitly request via the `--release` flag—e.g. `cargo build --release` or `cargo run --release`.
+The `test` profile is the default profile used by `cargo test`. The `test` profile inherits the settings form the `dev` profile.
+The `bench` profile is the default profile used by `cargo bench`. The `bench` profile inherits from the `release` profile.
+Use `dev` for iterative development and debugging, `release` for optimized production builds,\
+`test` for correctness testing, and `bench` for performance benchmarking.
+
+
 
 > "Have you built your project in release mode?" is almost a meme in the Rust community.\
 > It refers to developers who are not familiar with Rust and complain about its performance on