Lifetimes in Rust

It was always there, but now it's explicit

Recap: References

• &MyStruct is a reference/borrow of a struct
• If the underlying struct is removed, the reference is invalid
• In C++, it is entirely on you to manage this
• Rust just makes this management explicit

Motivation

	let x;
	{
		let y = 5;
		x = &y;
	} // uh oh
	println!("x: {}", x); // hmmm
	

Rust will not compile this code

Lifetimes

• These always exist.
• Sometimes the compiler needs some hints
• We can annotate lifetimes to add hints

Annotation Example

The borrow checker will use the shortest lifetime

Struct Example