Rust's memory safety guarantees do not insure the absence of leaks. However, Rust's design does offer significant protection against leaks (relative to language

Rust's memory safety guarantees do not insure the absence of leaks. However, Rust's design does offer significant protection against leaks (relative to languages like C where all heap allocations must be explicitly freed). The fact that any felt it nessasary to add a "leak" function to the standard library should tell you something about how easy it is to accidentally leak memory.