Unclear description in closure section of Rust Book

The first section on https://doc.rust-lang.org/stable/book/closures.html can be difficult to understand for novice programmers, particularly the line "Anonymous functions that have an associated environment are called ‘closures’, because they close over an environment." It's difficult from this context to understand what "environment" is referring to.

[steveklabnik]

Yeah, this definition is kind of embarassingly self-referential 😓

[chills42]

I'm going to try to clarify this.

[steveklabnik]

#28856 fixed this