Move rustfmt changes out

Now in rust-lang/rustfmt#6154

Cargo.lock

@@ -4884,6 +4884,7 @@ dependencies = [
  "getopts",
  "ignore",
  "itertools 0.11.0",
+ "lazy_static",
  "regex",
  "rustfmt-config_proc_macro",
  "serde",

src/tools/rustfmt/Cargo.toml

@@ -44,6 +44,7 @@ dirs = "4.0"
 getopts = "0.2"
 ignore = "0.4"
 itertools = "0.11"
+lazy_static = "1.4"
 regex = "1.7"
 serde = { version = "1.0.160", features = ["derive"] }
 serde_json = "1.0"

src/tools/rustfmt/src/comment.rs

@@ -3,6 +3,8 @@
 use std::{borrow::Cow, iter};
 
 use itertools::{multipeek, MultiPeek};
+use lazy_static::lazy_static;
+use regex::Regex;
 use rustc_span::Span;
 
 use crate::config::Config;
@@ -15,6 +17,17 @@ use crate::utils::{
 };
 use crate::{ErrorKind, FormattingError};
 
+lazy_static! {
+    /// A regex matching reference doc links.
+    ///
+    /// ```markdown
+    /// /// An [example].
+    /// ///
+    /// /// [example]: this::is::a::link
+    /// ```
+    static ref REFERENCE_LINK_URL: Regex = Regex::new(r"^\[.+\]\s?:").unwrap();
+}
+
 fn is_custom_comment(comment: &str) -> bool {
     if !comment.starts_with("//") {
         false
@@ -967,16 +980,11 @@ fn trim_custom_comment_prefix(s: &str) -> String {
 /// Returns `true` if the given string MAY include URLs or alike.
 fn has_url(s: &str) -> bool {
     // This function may return false positive, but should get its job done in most cases.
-    // The regex is indended to capture text such as the below.
-    //
-    // /// An [example].
-    // ///
-    // /// [example]: this::is::a::link
     s.contains("https://")
         || s.contains("http://")
         || s.contains("ftp://")
         || s.contains("file://")
-        || static_regex!(r"^\[.+\]\s?:").is_match(s)
+        || REFERENCE_LINK_URL.is_match(s)
 }
 
 /// Returns true if the given string may be part of a Markdown table.

src/tools/rustfmt/src/lib.rs

@@ -5,6 +5,9 @@
 #![allow(clippy::match_like_matches_macro)]
 #![allow(unreachable_pub)]
 
+#[cfg(test)]
+#[macro_use]
+extern crate lazy_static;
 #[macro_use]
 extern crate tracing;
 
@@ -59,13 +62,6 @@ pub use crate::rustfmt_diff::{ModifiedChunk, ModifiedLines};
 #[macro_use]
 mod utils;
 
-macro_rules! static_regex {
-    ($re:literal) => {{
-        static RE: ::std::sync::OnceLock<::regex::Regex> = ::std::sync::OnceLock::new();
-        RE.get_or_init(|| ::regex::Regex::new($re).unwrap())
-    }};
-}
-
 mod attr;
 mod chains;
 mod closures;

src/tools/rustfmt/src/test/configuration_snippet.rs

@@ -24,6 +24,19 @@ impl ConfigurationSection {
     fn get_section<I: Iterator<Item = String>>(
         file: &mut Enumerate<I>,
     ) -> Option<ConfigurationSection> {
+        lazy_static! {
+            static ref CONFIG_NAME_REGEX: regex::Regex =
+                regex::Regex::new(r"^## `([^`]+)`").expect("failed creating configuration pattern");
+            // Configuration values, which will be passed to `from_str`:
+            //
+            // - must be prefixed with `####`
+            // - must be wrapped in backticks
+            // - may by wrapped in double quotes (which will be stripped)
+            static ref CONFIG_VALUE_REGEX: regex::Regex =
+                regex::Regex::new(r#"^#### `"?([^`]+?)"?`"#)
+                    .expect("failed creating configuration value pattern");
+        }
+
         loop {
             match file.next() {
                 Some((i, line)) => {
@@ -40,14 +53,9 @@ impl ConfigurationSection {
                         let start_line = (i + 2) as u32;
 
                         return Some(ConfigurationSection::CodeBlock((block, start_line)));
-                    } else if let Some(c) = static_regex!(r"^## `([^`]+)`").captures(&line) {
+                    } else if let Some(c) = CONFIG_NAME_REGEX.captures(&line) {
                         return Some(ConfigurationSection::ConfigName(String::from(&c[1])));
-                    } else if let Some(c) = static_regex!(r#"^#### `"?([^`]+?)"?`"#).captures(&line) {
-                        // Configuration values, which will be passed to `from_str`
-                        //
-                        // - must be prefixed with `####`
-                        // - must be wrapped in backticks
-                        // - may by wrapped in double quotes (which will be stripped)
+                    } else if let Some(c) = CONFIG_VALUE_REGEX.captures(&line) {
                         return Some(ConfigurationSection::ConfigValue(String::from(&c[1])));
                     }
                 }