Problem

First example that is supposed to compile cleanly

$ git clone https://github.com/rust-lang/regex.git
$ cd regex

$ cargo build
Compiling regex v1.5.0 (file:///path/to/package/regex)

leslie@Fed35 ~$ cd regex/
leslie@Fed35 regex$ cargo build
GOT
Updating crates.io index
Compiling memchr v2.4.1
Compiling regex-syntax v0.6.25 (/home/leslie/regex/regex-syntax)
Compiling aho-corasick v0.7.18
warning: field is never read: printer
--> regex-syntax/src/ast/print.rs:66:5
|
66 | printer: &'p mut Printer,
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
= note: #[warn(dead_code)] on by default

warning: field is never read: printer
--> regex-syntax/src/hir/print.rs:74:5
|
74 | printer: &'p mut Printer,
| ^^^^^^^^^^^^^^^^^^^^^^^^

Compiling regex v1.5.4 (/home/leslie/regex)
warning: regex-syntax (lib) generated 2 warnings
Finished dev [unoptimized + debuginfo] target(s) in 5.10s

Steps

refer to listing

Possible Solution(s)

Please correct syntax errors so cloned example compiles cleanly

Notes

No response

Version

cargo --version
cargo 1.57.0 (b2e52d7ca 2021-10-21)