What essential safety features are removed? The only thing I can think of this referring to is assertions, and we do the opposite: assert stays in all builds, debug_assert is only in debug builds.
But it can overflow, which will result in a different value that the programmer might expect, which can give an attacker a nice "information leak" or worse. This could be a security bug!
And even wrt memory, Rust (with the standard library) is not free of its own warts, see the OOM situation.
See e.g https://news.ycombinator.com/item?id=10545877 for a discussion on this.
Just to be clear: I generally like the ideas of Rust. I just dislike its presentation by some as a magic solution to all kinds of concerns.
