Rust isn't even memory safe if you want to be THIS pedantic about it. the unsafe keyword exists in Rust, and it is often used.
In practice, Rust seems to be much safer. I've seen Jarred talking about segfaults in Bun. Those are practically unheard of in Rust programs, and indicative of the possibility of quite serious security vulnerabilities.
Safe APIs that contain unsafe blocks must still be proven correct, via Miri, a model checker, formal proof, etc. Any safe functions that violate memory safety are considered bugs. The limited number of unsafe functions exist as helpers to build safe APIs when the compiler's borrower checker is insufficient.
What this means is that to verify memory safety, one can restrict their search to unsafe blocks. And hypothetically if the Rust compiler were to get much smarter, it should be possible to prove to the compiler that those blocks are safe (via theorem prover, perhaps?) and remove the "unsafe" declaration.
In most languages, there is no such distinction between the "memory safe" common set users ought to use and the subset that has to be verified independently. Neither Zig, C, C++, nor even Go have a clear delineation between safe and unsafe code.
That's lack of memory safety when your memory safety work is done during compilation, as is the case with Rust.
Furthermore, no language is “memory safe” in the absolute sense. For example, not even the borrow checker can protect you from buffer bleeds.
