Chapter 4.5, final quiz, question 2

[xyzzycgn]

• I have searched open and closed issues and pull requests for duplicates, using these search terms:
  • 4.5
  • Chapter 4
  • &Vec
• I have checked the latest main branch to see if this has already been fixed, in this file:
  • rust-book/quizzes/ch04-05-ownership-recap.toml

URL to the section(s) of the book with this problem:
https://rust-book.cs.brown.edu/ch04-05-ownership-recap.html

Description of the problem:
The answer for the question says

For haystack, the slice type &[String] can accept more inputs than &Vec<String>, so it is preferred.

IMO this statement comes "out of the void" i.e. without a satisfying reasoning. A (short) explanation why &[String] can accept more inputs than &Vec<String> would be really helpful. In case that I've missing something in the main part of the book a reference to the accordingly chapter would be sufficient.

Suggested fix:
Adding an explanation or a reference to the accordingly chapter

[KGrewal1]

Adding on to this (as was going through the book to make sure I was solid on the basics with tests), I don't believe the suggested answer is valid as is either, as it needs lifetime annotations - would end up looking like

fn find_contains<'needle, 'haystack>(haystack: &'haystack [String], needle: &'needle str) -> Vec<&'haystack String>

to be valid, and maximally correct (as the output vector should be bound to the lifetime of the haystack)