But how does the Rust compiler do that? What does it actually check? Could I write a compiler in C that does this check on a piece of Rust code?

C is so simplictic, that if I can write a piece of functionality in C, I must understand its inner workings fully. Not just how to use the feature, but how the feature works under the hood.

It is often pointless to actually implement the feature in C, since the feature already has a good implementation (see the Rust compiler for the memory safety). But understanding these features, and being able to mentally think about what it takes in C to implement them, is still helpfull for gaining an understanding of the feature.

I mean, at the end of the day, if you really understand your language of choice, you know that it is jusf a bunch of fancy libraries and compiler tricks of top of C. So in my mind, I’m a fully evolved programmer in a language, when I could write anything I can write in that language in C instead.

I have this experience with a certain type of pedestrian traffic light “button”.

I quote button, because nothing physically moves when you press it. I’m not sure if it registers pressure or heat, but you don’t even feel anything move when you press it.

Usually when you press the button, a red text lights up on the button, telling you to wait. This text gives you feedback that the button registered your press, and the traffic light will schedule a green light for you.

However, sometimes you didn’t press hard enough, and the text doesn’t light up. Simple solution: press harder.

But there is a scenario where it doesn’t matter how hard you press, the button won’t light up. You keep staring at it, while slamming the damn thing with the fury of a Hulk wealding Mjolnir. Still, nothing lights up. The reason: the light instantly went green, so it never needed to light up the text telling you to wait. And all that time slamming your fist on the button, could have been spend crossing the intersection. Instead you have been standing there, looking like a drunk person having a fistfight with an inanimate object.