In C the return value would be NULL, except it was changed by musl at some point.

The type of the value in C is `char*`.

That's what led some people to write code where it crashes without checks. Which is still their mistake. But if the type was something that can't be implicitly used like an always-present value, that would have prevented the situation, even with those same people.

A pointer is a type where a null pointer can't be used as a regular value but leads to a trap when dereferenced.

By "can't be used as a regular value", I meant that it would be a compile-time error.

I see. For safety a run-time check is enough though.

But it turns out one can have a compile-time error forthis in C as well: https://godbolt.org/z/8E9z66cfs

You mean could be a `Result<T, E>`. There’s nothing in Rust that forces that.