"If it compiles, and the tests pass, it works" is more accurate; if your tests are pretty thorough, it's very unlikely that you've got any major logical errors, and Rust rules out a massive class of lifetime, double-use, mutability etc. errors just by being Rust.

I've translated pure-logic business code (with fairly thorough, albeit static, tests that all passed) from Python to Rust, and the compiler's complained about subtle errors that would have taken down a business using the code in days had they been put into production. Turns out there was a flaw in the spec.

Leveraging Rust's type system to logically separate the meanings of different integers, and only permitting arithmetic operations where meaningful (e.g. no distance+time, distance/time=speed), also uncovered a couple of even more subtle bugs – though luckily assertions would've caught these in the event of them actually making it through to production.

If it compiles, it probably works. But, more importantly, Rust forces you to write code that works in the first place. You have to think through the ramifications of what you're doing, sometimes to hold the entire function in your head at once, and that means you have to understand what you're doing. If you don't, it complains, and the chances are you won't be able to get it to compile until you do understand it.

And if it does compile when it's wrong, it's obviously wrong and your tests will fail. Most of the time.

Isn't programming fun?