[chapter 5-3] Losing R permission makes no sense

[Archsx]

• I have searched open and closed issues and pull requests for duplicates, using these search terms:
  • chapter 5-3
• I have checked the latest main branch to see if this has already been fixed, in this file:
  • https://github.com/cognitive-engineering-lab/rust-book/blob/main/src/ch05-03-method-syntax.md

URL to the section(s) of the book with this problem: https://rust-book.cs.brown.edu/ch05-03-method-syntax.html Description of the problem:

when using a immutable reference to refer a variable, it shows the variable(rect) losses the R permission.

Suggested fix:

[twhentschel]

I'm still learning this, but perhaps it's because the variable rect is no longer used after that point in the program, so it loses all permissions.

I redid this example in aquascope (the program that makes these type of borrow-checking figures in the book) but used rect one more time after it was aliased and this is what I got:

[willcrichton]

@twhentschel's explanation is exactly correct. It's an open issue in Aquascope to make these cases clearer. Hopefully we will improve this soon. See: cognitive-engineering-lab/aquascope#85