fn foo<'a>(_:&'a ()){} // #1
trait Trait<'b>
impl<'b> Trait<'b> for i32{} // #2
What's the terminology name of 'a and 'b in #1 and #2? #2 is, I heard from somewhere, named a higher-ranked implementation. So, what is the lifetime parameter named? Are they named as unbounded lifetime?
Those are just normal lifetime annotations.
Higher-ranked bounds are something else:
https://doc.rust-lang.org/reference/trait-bounds.html#higher-ranked-trait-bounds
If you heard #2 from me, I'm not sure how common of a phrase it is.
#1 is just "a lifetime parameter" as far as I know.
I don't know that "unbounded lifetime" is really a common phrase either. It makes me think of lifetimes that come out of nowhere. But I don't have anything close to a citation to back up that intuition.
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