[_nalply]

It's a complicated but well-thought out system which tends to avoid copies by making them explicit in the source code and preferring taking references or slices which are cheap operations.

The string slice for example is an Unicode-capable view into bytes of the string (immutably pre-compiled static bytes in the binary, bytes of fixed length on the stack or heap-allocated). The aliasing rules are enforced by the compiler, so it is safe to throw around pointers and sizes and not to worry about buffer overflows, as long as it compiles.