Rust isn't safe from race conditions. It is not a guarantee. It is free from memory errors, that is true, though.
You should read [1] to understand how Rust achieves this.
A data race has Undefined Behavior, and is therefore impossible to perform in Safe Rust.
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However Rust does not prevent general race conditions.
This is pretty fundamentally impossible, and probably honestly undesirable. Your hardware is racy, your OS is racy, the other programs on your computer are racy, and the world this all runs in is racy. Any system that could genuinely claim to prevent all race conditions would be pretty awful to use, if not just incorrect.
Maybe you should read a bit more on its docs [1]. I quote:
However Rust does not prevent general race conditions.