memory safe
A program that never reads or writes memory it doesn't own at that moment.
A memory-safe program performs no out-of-bounds access, use after free, double free or data race; safe Rust guarantees this at compile time, leaving unsafe blocks as the places that must be checked by hand.
Examples
A C++ buffer overrun that writes past a reading array into the next variable is a memory-safety bug; safe Rust refuses to compile the equivalent.
Rust is memory safe without a garbage collector, so ESP32 firmware gets the safety without pauses for collection.
See also