Why are explicit lifetimes needed in Rust?

Question

I was reading the lifetimes chapter of the Rust book, and I came across this example for a named/explicit lifetime:

struct Foo<\'a> {
    x: &\'a i         


        

Answer 1

The reason why your example does not work is simply because Rust only has local lifetime and type inference. What you are suggesting demands global inference. Whenever you have a reference whose lifetime cannot be elided, it must be annotated.