The three rules of lifetime elision in Rust

While reviewing some Rust fundamentals, I stumbled across this excellent video about lifetimes. What caught my attention the most was the “three rules” of lifetime elision – a topic I had some idea about, but I’ve never seen clearly explained.

For reference, they are:

• Each parameter that is a reference gets its own lifetime parameter;
• If there is exactly one input lifetime parameter, that lifetime is assigned to all output lifetime parameters;
• If there are multiple input lifetime parameters, but one of them is &self or &mut self, the lifetime of self is assigned to all output lifetime parameters.