Can there be a PDF too in the release?

PDF page 180 ("What's a possible error inducing operation on string slice range indices?"), I'm not sure what the first_word function is supposed to be:

1. It returns a usize, not a slice, even though that area of the deck is about slices,
2. If it's supposed to show a problem with slicing in between UTF-8 character, b' ' is a single byte character, so it's valid to slice at that boundary (it would be invalid if item was in the range 0x80-0xBF, i.e. of the form 0x10xxxxxx)
3. If it's the beginning of the page 181 question, then it's at the wrong place (but then also see next point of this issue)

page 181/182:
It mentions a first_word function, but if the function from page 180, then see point 1 above, which does compile since word is then the usize 5, and not a reference to the "hello" slice.

Currently blocked by kamalsacranie/anki-panky#5

Some cards are truncated in the PDF.

Some examples:

• Page 110 (loop labels), where the code is truncated but one could think it's just
• Page 114 ("Looping through a collection like this is a bad idea. Give 2 reasons why.") only shows the first part of the detailed explanation ("error prone") and not the 2nd ("slow").
• Page 116 ("What is a better and more concise alternative to loop over the array?"), missing the last sentence ("The safety and conciseness of for loops ...")
• Page 128 ("What happens in terms of the heap and stack when we assign s1 to s2 in line 2?") only show part of the "s1" variable and nothing of "s2" or the heap.
• ...

Current answer

We can use curly brackets to create a new scope, allowing for multiple mutable references, just not simultaneous ones:

fn main() {
  let mut s: String = String::from("Hello");
  {
    let r1: &mut String = &mut s;
    // r1 goes out of scope here,
  }
  // So we can make a new reference with no problems
  let r2: &mut String = &mut s;
}

Proposal

I think this answer is not correct. In fact thanks to NLL the above code works without curly braces too (https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=6b2144aeb8d82883ec17cb94af60c888).

At first, I would have answered to use a Mutex. So I'm not sure how to update this card.

1. Remove it
2. Use an example that does not compile, for instance the one at the end of https://blog.rust-lang.org/2022/08/05/nll-by-default.html, but here the solution is not about adding curly braces
3. Update the question to point to a Mutex answer