Merging upstream version 1.66.0+dfsg1.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

16 files changed, 316 insertions, 171 deletions

diff --git a/src/tools/tidy/src/alphabetical.rs b/src/tools/tidy/src/alphabetical.rs
new file mode 100644
index 000000000..f913f6cde
--- /dev/null
+++ b/src/tools/tidy/src/alphabetical.rs
@@ -0,0 +1,111 @@
+//! Checks that a list of items is in alphabetical order
+//!
+//! To use, use the following annotation in the code:
+//! ```rust
+//! // tidy-alphabetical-start
+//! fn aaa() {}
+//! fn eee() {}
+//! fn z() {}
+//! // tidy-alphabetical-end
+//! ```
+//!
+//! The following lines are ignored:
+//! - Lines that are indented with more or less spaces than the first line
+//! - Lines starting with `//`, `#[`, `)`, `]`, `}` if the comment has the same indentation as
+//!   the first line
+//!
+//! If a line ends with an opening bracket, the line is ignored and the next line will have
+//! its extra indentation ignored.
+
+use std::{fmt::Display, path::Path};
+
+use crate::walk::{filter_dirs, walk};
+
+fn indentation(line: &str) -> usize {
+    line.find(|c| c != ' ').unwrap_or(0)
+}
+
+fn is_close_bracket(c: char) -> bool {
+    matches!(c, ')' | ']' | '}')
+}
+
+// Don't let tidy check this here :D
+const START_COMMENT: &str = concat!("// tidy-alphabetical", "-start");
+const END_COMMENT: &str = "// tidy-alphabetical-end";
+
+fn check_section<'a>(
+    file: impl Display,
+    lines: impl Iterator<Item = (usize, &'a str)>,
+    bad: &mut bool,
+) {
+    let content_lines = lines.take_while(|(_, line)| !line.contains(END_COMMENT));
+
+    let mut prev_line = String::new();
+    let mut first_indent = None;
+    let mut in_split_line = None;
+
+    for (line_idx, line) in content_lines {
+        if line.contains(START_COMMENT) {
+            tidy_error!(
+                bad,
+                "{file}:{} found `{START_COMMENT}` expecting `{END_COMMENT}`",
+                line_idx
+            )
+        }
+
+        let indent = first_indent.unwrap_or_else(|| {
+            let indent = indentation(line);
+            first_indent = Some(indent);
+            indent
+        });
+
+        let line = if let Some(prev_split_line) = in_split_line {
+            in_split_line = None;
+            format!("{prev_split_line}{}", line.trim_start())
+        } else {
+            line.to_string()
+        };
+
+        if indentation(&line) != indent {
+            continue;
+        }
+
+        let trimmed_line = line.trim_start_matches(' ');
+
+        if trimmed_line.starts_with("//")
+            || trimmed_line.starts_with("#[")
+            || trimmed_line.starts_with(is_close_bracket)
+        {
+            continue;
+        }
+
+        if line.trim_end().ends_with('(') {
+            in_split_line = Some(line);
+            continue;
+        }
+
+        let prev_line_trimmed_lowercase = prev_line.trim_start_matches(' ').to_lowercase();
+
+        if trimmed_line.to_lowercase() < prev_line_trimmed_lowercase {
+            tidy_error!(bad, "{file}:{}: line not in alphabetical order", line_idx + 1,);
+        }
+
+        prev_line = line;
+    }
+}
+
+pub fn check(path: &Path, bad: &mut bool) {
+    walk(path, &mut filter_dirs, &mut |entry, contents| {
+        let file = &entry.path().display();
+
+        let mut lines = contents.lines().enumerate().peekable();
+        while let Some((_, line)) = lines.next() {
+            if line.contains(START_COMMENT) {
+                check_section(file, &mut lines, bad);
+                if lines.peek().is_none() {
+                    tidy_error!(bad, "{file}: reached end of file expecting `{END_COMMENT}`")
+                }
+            }
+        }
+    });
+}
diff --git a/src/tools/tidy/src/bins.rs b/src/tools/tidy/src/bins.rs
index 30903f56d..b898f20a5 100644
--- a/src/tools/tidy/src/bins.rs
+++ b/src/tools/tidy/src/bins.rs
@@ -21,6 +21,7 @@ mod os_impl {
 
 #[cfg(unix)]
 mod os_impl {
+    use crate::walk::{filter_dirs, walk_no_read};
     use std::fs;
     use std::os::unix::prelude::*;
     use std::path::Path;
@@ -100,10 +101,10 @@ mod os_impl {
 
         const ALLOWED: &[&str] = &["configure", "x"];
 
-        crate::walk_no_read(
+        walk_no_read(
             path,
             &mut |path| {
-                crate::filter_dirs(path)
+                filter_dirs(path)
                     || path.ends_with("src/etc")
                     // This is a list of directories that we almost certainly
                     // don't need to walk. A future PR will likely want to
diff --git a/src/tools/tidy/src/debug_artifacts.rs b/src/tools/tidy/src/debug_artifacts.rs
index ab87230f8..9880a32ad 100644
--- a/src/tools/tidy/src/debug_artifacts.rs
+++ b/src/tools/tidy/src/debug_artifacts.rs
@@ -1,5 +1,6 @@
 //! Tidy check to prevent creation of unnecessary debug artifacts while running tests.
 
+use crate::walk::{filter_dirs, walk};
 use std::path::{Path, PathBuf};
 
 const GRAPHVIZ_POSTFLOW_MSG: &str = "`borrowck_graphviz_postflow` attribute in test";
@@ -7,7 +8,7 @@ const GRAPHVIZ_POSTFLOW_MSG: &str = "`borrowck_graphviz_postflow` attribute in t
 pub fn check(path: &Path, bad: &mut bool) {
     let test_dir: PathBuf = path.join("test");
 
-    super::walk(&test_dir, &mut super::filter_dirs, &mut |entry, contents| {
+    walk(&test_dir, &mut filter_dirs, &mut |entry, contents| {
         let filename = entry.path();
         let is_rust = filename.extension().map_or(false, |ext| ext == "rs");
         if !is_rust {
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index cbd8cfa01..8a0239ece 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -18,9 +18,11 @@ const LICENSES: &[&str] = &[
     "ISC",
     "Unlicense/MIT",
     "Unlicense OR MIT",
-    "0BSD OR MIT OR Apache-2.0", // adler license
-    "Zlib OR Apache-2.0 OR MIT", // tinyvec
-    "MIT OR Zlib OR Apache-2.0", // miniz_oxide
+    "0BSD OR MIT OR Apache-2.0",                // adler license
+    "Zlib OR Apache-2.0 OR MIT",                // tinyvec
+    "MIT OR Apache-2.0 OR Zlib",                // tinyvec_macros
+    "MIT OR Zlib OR Apache-2.0",                // miniz_oxide
+    "(MIT OR Apache-2.0) AND Unicode-DFS-2016", // unicode_ident
 ];
 
 /// These are exceptions to Rust's permissive licensing policy, and
@@ -72,14 +74,11 @@ const EXCEPTIONS_BOOTSTRAP: &[(&str, &str)] = &[
 /// these and all their dependencies *must not* be in the exception list.
 const RUNTIME_CRATES: &[&str] = &["std", "core", "alloc", "test", "panic_abort", "panic_unwind"];
 
-/// Crates whose dependencies must be explicitly permitted.
-const RESTRICTED_DEPENDENCY_CRATES: &[&str] = &["rustc_driver", "rustc_codegen_llvm"];
-
 /// Crates rustc is allowed to depend on. Avoid adding to the list if possible.
 ///
 /// This list is here to provide a speed-bump to adding a new dependency to
 /// rustc. Please check with the compiler team before adding an entry.
-const PERMITTED_DEPENDENCIES: &[&str] = &[
+const PERMITTED_RUSTC_DEPENDENCIES: &[&str] = &[
     "addr2line",
     "adler",
     "ahash",
@@ -218,6 +217,7 @@ const PERMITTED_DEPENDENCIES: &[&str] = &[
     "time",
     "tinystr",
     "tinyvec",
+    "tinyvec_macros",
     "thin-vec",
     "tracing",
     "tracing-attributes",
@@ -236,6 +236,7 @@ const PERMITTED_DEPENDENCIES: &[&str] = &[
     "unic-langid-macros",
     "unic-langid-macros-impl",
     "unic-ucd-version",
+    "unicode-ident",
     "unicode-normalization",
     "unicode-script",
     "unicode-security",
@@ -258,7 +259,9 @@ const PERMITTED_CRANELIFT_DEPENDENCIES: &[&str] = &[
     "ahash",
     "anyhow",
     "ar",
+    "arrayvec",
     "autocfg",
+    "bumpalo",
     "bitflags",
     "byteorder",
     "cfg-if",
@@ -305,7 +308,7 @@ const PERMITTED_CRANELIFT_DEPENDENCIES: &[&str] = &[
 ];
 
 const FORBIDDEN_TO_HAVE_DUPLICATES: &[&str] = &[
-    // These two crates take quite a long time to build, so don't allow two versions of them
+    // This crate takes quite a long time to build, so don't allow two versions of them
     // to accidentally sneak into our dependency graph, in order to ensure we keep our CI times
     // under control.
     "cargo",
@@ -322,12 +325,12 @@ pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
         .features(cargo_metadata::CargoOpt::AllFeatures);
     let metadata = t!(cmd.exec());
     let runtime_ids = compute_runtime_crates(&metadata);
-    check_exceptions(&metadata, EXCEPTIONS, runtime_ids, bad);
-    check_dependencies(
+    check_license_exceptions(&metadata, EXCEPTIONS, runtime_ids, bad);
+    check_permitted_dependencies(
         &metadata,
-        "main workspace",
-        PERMITTED_DEPENDENCIES,
-        RESTRICTED_DEPENDENCY_CRATES,
+        "rustc",
+        PERMITTED_RUSTC_DEPENDENCIES,
+        &["rustc_driver", "rustc_codegen_llvm"],
         bad,
     );
     check_crate_duplicate(&metadata, FORBIDDEN_TO_HAVE_DUPLICATES, bad);
@@ -340,8 +343,8 @@ pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
         .features(cargo_metadata::CargoOpt::AllFeatures);
     let metadata = t!(cmd.exec());
     let runtime_ids = HashSet::new();
-    check_exceptions(&metadata, EXCEPTIONS_CRANELIFT, runtime_ids, bad);
-    check_dependencies(
+    check_license_exceptions(&metadata, EXCEPTIONS_CRANELIFT, runtime_ids, bad);
+    check_permitted_dependencies(
         &metadata,
         "cranelift",
         PERMITTED_CRANELIFT_DEPENDENCIES,
@@ -356,13 +359,13 @@ pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
         .features(cargo_metadata::CargoOpt::AllFeatures);
     let metadata = t!(cmd.exec());
     let runtime_ids = HashSet::new();
-    check_exceptions(&metadata, EXCEPTIONS_BOOTSTRAP, runtime_ids, bad);
+    check_license_exceptions(&metadata, EXCEPTIONS_BOOTSTRAP, runtime_ids, bad);
 }
 
 /// Check that all licenses are in the valid list in `LICENSES`.
 ///
-/// Packages listed in `EXCEPTIONS` are allowed for tools.
-fn check_exceptions(
+/// Packages listed in `exceptions` are allowed for tools.
+fn check_license_exceptions(
     metadata: &Metadata,
     exceptions: &[(&str, &str)],
     runtime_ids: HashSet<&PackageId>,
@@ -432,11 +435,11 @@ fn check_exceptions(
     }
 }
 
-/// Checks the dependency of `RESTRICTED_DEPENDENCY_CRATES` at the given path. Changes `bad` to
+/// Checks the dependency of `restricted_dependency_crates` at the given path. Changes `bad` to
 /// `true` if a check failed.
 ///
-/// Specifically, this checks that the dependencies are on the `PERMITTED_DEPENDENCIES`.
-fn check_dependencies(
+/// Specifically, this checks that the dependencies are on the `permitted_dependencies`.
+fn check_permitted_dependencies(
     metadata: &Metadata,
     descr: &str,
     permitted_dependencies: &[&'static str],
diff --git a/src/tools/tidy/src/edition.rs b/src/tools/tidy/src/edition.rs
index b0abee459..8a7c4460d 100644
--- a/src/tools/tidy/src/edition.rs
+++ b/src/tools/tidy/src/edition.rs
@@ -1,5 +1,6 @@
 //! Tidy check to ensure that crate `edition` is '2018' or '2021'.
 
+use crate::walk::{filter_dirs, walk};
 use std::path::Path;
 
 fn is_edition_2021(mut line: &str) -> bool {
@@ -8,9 +9,9 @@ fn is_edition_2021(mut line: &str) -> bool {
 }
 
 pub fn check(path: &Path, bad: &mut bool) {
-    super::walk(
+    walk(
         path,
-        &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
+        &mut |path| filter_dirs(path) || path.ends_with("src/test"),
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap();
diff --git a/src/tools/tidy/src/error_codes_check.rs b/src/tools/tidy/src/error_codes_check.rs
index 0a226443e..610e322e1 100644
--- a/src/tools/tidy/src/error_codes_check.rs
+++ b/src/tools/tidy/src/error_codes_check.rs
@@ -1,6 +1,7 @@
 //! Checks that all error codes have at least one test to prevent having error
 //! codes that are silently not thrown by the compiler anymore.
 
+use crate::walk::{filter_dirs, walk};
 use std::collections::{HashMap, HashSet};
 use std::ffi::OsStr;
 use std::fs::read_to_string;
@@ -217,7 +218,7 @@ pub fn check(paths: &[&Path], bad: &mut bool) {
     println!("Checking which error codes lack tests...");
 
     for path in paths {
-        super::walk(path, &mut super::filter_dirs, &mut |entry, contents| {
+        walk(path, &mut filter_dirs, &mut |entry, contents| {
             let file_name = entry.file_name();
             let entry_path = entry.path();
 
diff --git a/src/tools/tidy/src/errors.rs b/src/tools/tidy/src/errors.rs
index dbcc9341a..fe5fd72b9 100644
--- a/src/tools/tidy/src/errors.rs
+++ b/src/tools/tidy/src/errors.rs
@@ -3,14 +3,15 @@
 //! This ensures that error codes are used at most once and also prints out some
 //! statistics about the error codes.
 
+use crate::walk::{filter_dirs, walk};
 use std::collections::HashMap;
 use std::path::Path;
 
 pub fn check(path: &Path, bad: &mut bool) {
     let mut map: HashMap<_, Vec<_>> = HashMap::new();
-    super::walk(
+    walk(
         path,
-        &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
+        &mut |path| filter_dirs(path) || path.ends_with("src/test"),
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap().to_string_lossy();
diff --git a/src/tools/tidy/src/features.rs b/src/tools/tidy/src/features.rs
index b306a527a..f10ecf5f2 100644
--- a/src/tools/tidy/src/features.rs
+++ b/src/tools/tidy/src/features.rs
@@ -9,7 +9,8 @@
 //! * All unstable lang features have tests to ensure they are actually unstable.
 //! * Language features in a group are sorted by feature name.
 
-use std::collections::HashMap;
+use crate::walk::{filter_dirs, walk, walk_many};
+use std::collections::hash_map::{Entry, HashMap};
 use std::fmt;
 use std::fs;
 use std::num::NonZeroU32;
@@ -92,14 +93,14 @@ pub fn check(
     let lib_features = get_and_check_lib_features(lib_path, bad, &features);
     assert!(!lib_features.is_empty());
 
-    super::walk_many(
+    walk_many(
         &[
             &src_path.join("test/ui"),
             &src_path.join("test/ui-fulldeps"),
             &src_path.join("test/rustdoc-ui"),
             &src_path.join("test/rustdoc"),
         ],
-        &mut |path| super::filter_dirs(path),
+        &mut filter_dirs,
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap().to_string_lossy();
@@ -279,13 +280,14 @@ fn test_filen_gate(filen_underscore: &str, features: &mut Features) -> bool {
 }
 
 pub fn collect_lang_features(base_compiler_path: &Path, bad: &mut bool) -> Features {
-    let mut all = collect_lang_features_in(base_compiler_path, "active.rs", bad);
-    all.extend(collect_lang_features_in(base_compiler_path, "accepted.rs", bad));
-    all.extend(collect_lang_features_in(base_compiler_path, "removed.rs", bad));
-    all
+    let mut features = Features::new();
+    collect_lang_features_in(&mut features, base_compiler_path, "active.rs", bad);
+    collect_lang_features_in(&mut features, base_compiler_path, "accepted.rs", bad);
+    collect_lang_features_in(&mut features, base_compiler_path, "removed.rs", bad);
+    features
 }
 
-fn collect_lang_features_in(base: &Path, file: &str, bad: &mut bool) -> Features {
+fn collect_lang_features_in(features: &mut Features, base: &Path, file: &str, bad: &mut bool) {
     let path = base.join("rustc_feature").join("src").join(file);
     let contents = t!(fs::read_to_string(&path));
 
@@ -297,135 +299,145 @@ fn collect_lang_features_in(base: &Path, file: &str, bad: &mut bool) -> Features
     let mut in_feature_group = false;
     let mut prev_names = vec![];
 
-    contents
-        .lines()
-        .zip(1..)
-        .filter_map(|(line, line_number)| {
-            let line = line.trim();
-
-            // Within -start and -end, the tracking issue can be omitted.
-            match line {
-                "// no-tracking-issue-start" => {
-                    next_feature_omits_tracking_issue = true;
-                    return None;
-                }
-                "// no-tracking-issue-end" => {
-                    next_feature_omits_tracking_issue = false;
-                    return None;
-                }
-                _ => {}
+    let lines = contents.lines().zip(1..);
+    for (line, line_number) in lines {
+        let line = line.trim();
+
+        // Within -start and -end, the tracking issue can be omitted.
+        match line {
+            "// no-tracking-issue-start" => {
+                next_feature_omits_tracking_issue = true;
+                continue;
             }
+            "// no-tracking-issue-end" => {
+                next_feature_omits_tracking_issue = false;
+                continue;
+            }
+            _ => {}
+        }
 
-            if line.starts_with(FEATURE_GROUP_START_PREFIX) {
-                if in_feature_group {
-                    tidy_error!(
-                        bad,
-                        "{}:{}: \
+        if line.starts_with(FEATURE_GROUP_START_PREFIX) {
+            if in_feature_group {
+                tidy_error!(
+                    bad,
+                    "{}:{}: \
                         new feature group is started without ending the previous one",
-                        path.display(),
-                        line_number,
-                    );
-                }
-
-                in_feature_group = true;
-                prev_names = vec![];
-                return None;
-            } else if line.starts_with(FEATURE_GROUP_END_PREFIX) {
-                in_feature_group = false;
-                prev_names = vec![];
-                return None;
+                    path.display(),
+                    line_number,
+                );
             }
 
-            let mut parts = line.split(',');
-            let level = match parts.next().map(|l| l.trim().trim_start_matches('(')) {
-                Some("active") => Status::Unstable,
-                Some("incomplete") => Status::Unstable,
-                Some("removed") => Status::Removed,
-                Some("accepted") => Status::Stable,
-                _ => return None,
-            };
-            let name = parts.next().unwrap().trim();
-
-            let since_str = parts.next().unwrap().trim().trim_matches('"');
-            let since = match since_str.parse() {
-                Ok(since) => Some(since),
-                Err(err) => {
-                    tidy_error!(
-                        bad,
-                        "{}:{}: failed to parse since: {} ({:?})",
-                        path.display(),
-                        line_number,
-                        since_str,
-                        err,
-                    );
-                    None
-                }
-            };
-            if in_feature_group {
-                if prev_names.last() > Some(&name) {
-                    // This assumes the user adds the feature name at the end of the list, as we're
-                    // not looking ahead.
-                    let correct_index = match prev_names.binary_search(&name) {
-                        Ok(_) => {
-                            // This only occurs when the feature name has already been declared.
-                            tidy_error!(
-                                bad,
-                                "{}:{}: duplicate feature {}",
-                                path.display(),
-                                line_number,
-                                name,
-                            );
-                            // skip any additional checks for this line
-                            return None;
-                        }
-                        Err(index) => index,
-                    };
+            in_feature_group = true;
+            prev_names = vec![];
+            continue;
+        } else if line.starts_with(FEATURE_GROUP_END_PREFIX) {
+            in_feature_group = false;
+            prev_names = vec![];
+            continue;
+        }
 
-                    let correct_placement = if correct_index == 0 {
-                        "at the beginning of the feature group".to_owned()
-                    } else if correct_index == prev_names.len() {
-                        // I don't believe this is reachable given the above assumption, but it
-                        // doesn't hurt to be safe.
-                        "at the end of the feature group".to_owned()
-                    } else {
-                        format!(
-                            "between {} and {}",
-                            prev_names[correct_index - 1],
-                            prev_names[correct_index],
-                        )
-                    };
+        let mut parts = line.split(',');
+        let level = match parts.next().map(|l| l.trim().trim_start_matches('(')) {
+            Some("active") => Status::Unstable,
+            Some("incomplete") => Status::Unstable,
+            Some("removed") => Status::Removed,
+            Some("accepted") => Status::Stable,
+            _ => continue,
+        };
+        let name = parts.next().unwrap().trim();
+
+        let since_str = parts.next().unwrap().trim().trim_matches('"');
+        let since = match since_str.parse() {
+            Ok(since) => Some(since),
+            Err(err) => {
+                tidy_error!(
+                    bad,
+                    "{}:{}: failed to parse since: {} ({:?})",
+                    path.display(),
+                    line_number,
+                    since_str,
+                    err,
+                );
+                None
+            }
+        };
+        if in_feature_group {
+            if prev_names.last() > Some(&name) {
+                // This assumes the user adds the feature name at the end of the list, as we're
+                // not looking ahead.
+                let correct_index = match prev_names.binary_search(&name) {
+                    Ok(_) => {
+                        // This only occurs when the feature name has already been declared.
+                        tidy_error!(
+                            bad,
+                            "{}:{}: duplicate feature {}",
+                            path.display(),
+                            line_number,
+                            name,
+                        );
+                        // skip any additional checks for this line
+                        continue;
+                    }
+                    Err(index) => index,
+                };
 
-                    tidy_error!(
-                        bad,
-                        "{}:{}: feature {} is not sorted by feature name (should be {})",
-                        path.display(),
-                        line_number,
-                        name,
-                        correct_placement,
-                    );
-                }
-                prev_names.push(name);
+                let correct_placement = if correct_index == 0 {
+                    "at the beginning of the feature group".to_owned()
+                } else if correct_index == prev_names.len() {
+                    // I don't believe this is reachable given the above assumption, but it
+                    // doesn't hurt to be safe.
+                    "at the end of the feature group".to_owned()
+                } else {
+                    format!(
+                        "between {} and {}",
+                        prev_names[correct_index - 1],
+                        prev_names[correct_index],
+                    )
+                };
+
+                tidy_error!(
+                    bad,
+                    "{}:{}: feature {} is not sorted by feature name (should be {})",
+                    path.display(),
+                    line_number,
+                    name,
+                    correct_placement,
+                );
             }
+            prev_names.push(name);
+        }
 
-            let issue_str = parts.next().unwrap().trim();
-            let tracking_issue = if issue_str.starts_with("None") {
-                if level == Status::Unstable && !next_feature_omits_tracking_issue {
-                    tidy_error!(
-                        bad,
-                        "{}:{}: no tracking issue for feature {}",
-                        path.display(),
-                        line_number,
-                        name,
-                    );
-                }
-                None
-            } else {
-                let s = issue_str.split('(').nth(1).unwrap().split(')').next().unwrap();
-                Some(s.parse().unwrap())
-            };
-            Some((name.to_owned(), Feature { level, since, has_gate_test: false, tracking_issue }))
-        })
-        .collect()
+        let issue_str = parts.next().unwrap().trim();
+        let tracking_issue = if issue_str.starts_with("None") {
+            if level == Status::Unstable && !next_feature_omits_tracking_issue {
+                tidy_error!(
+                    bad,
+                    "{}:{}: no tracking issue for feature {}",
+                    path.display(),
+                    line_number,
+                    name,
+                );
+            }
+            None
+        } else {
+            let s = issue_str.split('(').nth(1).unwrap().split(')').next().unwrap();
+            Some(s.parse().unwrap())
+        };
+        match features.entry(name.to_owned()) {
+            Entry::Occupied(e) => {
+                tidy_error!(
+                    bad,
+                    "{}:{} feature {name} already specified with status '{}'",
+                    path.display(),
+                    line_number,
+                    e.get().level,
+                );
+            }
+            Entry::Vacant(e) => {
+                e.insert(Feature { level, since, has_gate_test: false, tracking_issue });
+            }
+        }
+    }
 }
 
 fn get_and_check_lib_features(
@@ -466,9 +478,9 @@ fn map_lib_features(
     base_src_path: &Path,
     mf: &mut dyn FnMut(Result<(&str, Feature), &str>, &Path, usize),
 ) {
-    super::walk(
+    walk(
         base_src_path,
-        &mut |path| super::filter_dirs(path) || path.ends_with("src/test"),
+        &mut |path| filter_dirs(path) || path.ends_with("src/test"),
         &mut |entry, contents| {
             let file = entry.path();
             let filename = file.file_name().unwrap().to_string_lossy();
@@ -537,7 +549,9 @@ fn map_lib_features(
                 becoming_feature = None;
                 if line.contains("rustc_const_unstable(") {
                     // `const fn` features are handled specially.
-                    let feature_name = match find_attr_val(line, "feature") {
+                    let feature_name = match find_attr_val(line, "feature").or_else(|| {
+                        iter_lines.peek().and_then(|next| find_attr_val(next.1, "feature"))
+                    }) {
                         Some(name) => name,
                         None => err!("malformed stability attribute: missing `feature` key"),
                     };
diff --git a/src/tools/tidy/src/lib.rs b/src/tools/tidy/src/lib.rs
index 12d3bdcd7..fc0bce585 100644
--- a/src/tools/tidy/src/lib.rs
+++ b/src/tools/tidy/src/lib.rs
@@ -3,8 +3,6 @@
 //! This library contains the tidy lints and exposes it
 //! to be used by tools.
 
-use walk::{filter_dirs, walk, walk_many, walk_no_read};
-
 /// A helper macro to `unwrap` a result except also print out details like:
 ///
 /// * The expression that failed
@@ -40,6 +38,7 @@ macro_rules! tidy_error {
     });
 }
 
+pub mod alphabetical;
 pub mod bins;
 pub mod debug_artifacts;
 pub mod deps;
diff --git a/src/tools/tidy/src/main.rs b/src/tools/tidy/src/main.rs
index c1ce94f47..ca785042a 100644
--- a/src/tools/tidy/src/main.rs
+++ b/src/tools/tidy/src/main.rs
@@ -90,6 +90,10 @@ fn main() {
         check!(edition, &compiler_path);
         check!(edition, &library_path);
 
+        check!(alphabetical, &src_path);
+        check!(alphabetical, &compiler_path);
+        check!(alphabetical, &library_path);
+
         let collected = {
             while handles.len() >= concurrency.get() {
                 handles.pop_front().unwrap().join().unwrap();
diff --git a/src/tools/tidy/src/pal.rs b/src/tools/tidy/src/pal.rs
index 4d86fe8be..f4592fdcf 100644
--- a/src/tools/tidy/src/pal.rs
+++ b/src/tools/tidy/src/pal.rs
@@ -30,6 +30,7 @@
 //! platform-specific cfgs are allowed. Not sure yet how to deal with
 //! this in the long term.
 
+use crate::walk::{filter_dirs, walk};
 use std::iter::Iterator;
 use std::path::Path;
 
@@ -67,7 +68,7 @@ pub fn check(path: &Path, bad: &mut bool) {
     // Sanity check that the complex parsing here works.
     let mut saw_target_arch = false;
     let mut saw_cfg_bang = false;
-    super::walk(path, &mut super::filter_dirs, &mut |entry, contents| {
+    walk(path, &mut filter_dirs, &mut |entry, contents| {
         let file = entry.path();
         let filestr = file.to_string_lossy().replace("\\", "/");
         if !filestr.ends_with(".rs") {
diff --git a/src/tools/tidy/src/style.rs b/src/tools/tidy/src/style.rs
index dee58ff2f..541380ceb 100644
--- a/src/tools/tidy/src/style.rs
+++ b/src/tools/tidy/src/style.rs
@@ -16,6 +16,7 @@
 //! A number of these checks can be opted-out of with various directives of the form:
 //! `// ignore-tidy-CHECK-NAME`.
 
+use crate::walk::{filter_dirs, walk};
 use regex::Regex;
 use std::path::Path;
 
@@ -218,13 +219,13 @@ fn is_unexplained_ignore(extension: &str, line: &str) -> bool {
 
 pub fn check(path: &Path, bad: &mut bool) {
     fn skip(path: &Path) -> bool {
-        super::filter_dirs(path) || skip_markdown_path(path)
+        filter_dirs(path) || skip_markdown_path(path)
     }
     let problematic_consts_strings: Vec<String> = (PROBLEMATIC_CONSTS.iter().map(u32::to_string))
         .chain(PROBLEMATIC_CONSTS.iter().map(|v| format!("{:x}", v)))
         .chain(PROBLEMATIC_CONSTS.iter().map(|v| format!("{:X}", v)))
         .collect();
-    super::walk(path, &mut skip, &mut |entry, contents| {
+    walk(path, &mut skip, &mut |entry, contents| {
         let file = entry.path();
         let filename = file.file_name().unwrap().to_string_lossy();
         let extensions = [".rs", ".py", ".js", ".sh", ".c", ".cpp", ".h", ".md", ".css", ".ftl"];
diff --git a/src/tools/tidy/src/target_specific_tests.rs b/src/tools/tidy/src/target_specific_tests.rs
index 723684bfa..8ba257056 100644
--- a/src/tools/tidy/src/target_specific_tests.rs
+++ b/src/tools/tidy/src/target_specific_tests.rs
@@ -36,7 +36,7 @@ struct RevisionInfo<'a> {
 
 pub fn check(path: &Path, bad: &mut bool) {
     let tests = path.join("test");
-    super::walk(
+    crate::walk::walk(
         &tests,
         &mut |path| path.extension().map(|p| p == "rs") == Some(false),
         &mut |entry, content| {
diff --git a/src/tools/tidy/src/ui_tests.rs b/src/tools/tidy/src/ui_tests.rs
index 8ec5c3324..c600f99c2 100644
--- a/src/tools/tidy/src/ui_tests.rs
+++ b/src/tools/tidy/src/ui_tests.rs
@@ -7,8 +7,8 @@ use std::path::Path;
 
 const ENTRY_LIMIT: usize = 1000;
 // FIXME: The following limits should be reduced eventually.
-const ROOT_ENTRY_LIMIT: usize = 968;
-const ISSUES_ENTRY_LIMIT: usize = 2147;
+const ROOT_ENTRY_LIMIT: usize = 948;
+const ISSUES_ENTRY_LIMIT: usize = 2117;
 
 fn check_entries(path: &Path, bad: &mut bool) {
     let dirs = walkdir::WalkDir::new(&path.join("test/ui"))
@@ -47,7 +47,7 @@ fn check_entries(path: &Path, bad: &mut bool) {
 pub fn check(path: &Path, bad: &mut bool) {
     check_entries(&path, bad);
     for path in &[&path.join("test/ui"), &path.join("test/ui-fulldeps")] {
-        super::walk_no_read(path, &mut |_| false, &mut |entry| {
+        crate::walk::walk_no_read(path, &mut |_| false, &mut |entry| {
             let file_path = entry.path();
             if let Some(ext) = file_path.extension() {
                 if ext == "stderr" || ext == "stdout" {
diff --git a/src/tools/tidy/src/unit_tests.rs b/src/tools/tidy/src/unit_tests.rs
index f675b7865..2c23b6ebc 100644
--- a/src/tools/tidy/src/unit_tests.rs
+++ b/src/tools/tidy/src/unit_tests.rs
@@ -7,6 +7,7 @@
 //! named `tests.rs` or `benches.rs`, or directories named `tests` or `benches` unconfigured
 //! during normal build.
 
+use crate::walk::{filter_dirs, walk};
 use std::path::Path;
 
 pub fn check(root_path: &Path, bad: &mut bool) {
@@ -20,7 +21,7 @@ pub fn check(root_path: &Path, bad: &mut bool) {
     let mut skip = |path: &Path| {
         let file_name = path.file_name().unwrap_or_default();
         if path.is_dir() {
-            super::filter_dirs(path)
+            filter_dirs(path)
                 || path.ends_with("src/test")
                 || path.ends_with("src/doc")
                 || (file_name == "tests" || file_name == "benches") && !is_core(path)
@@ -34,7 +35,7 @@ pub fn check(root_path: &Path, bad: &mut bool) {
         }
     };
 
-    super::walk(root_path, &mut skip, &mut |entry, contents| {
+    walk(root_path, &mut skip, &mut |entry, contents| {
         let path = entry.path();
         let is_core = path.starts_with(core);
         for (i, line) in contents.lines().enumerate() {
diff --git a/src/tools/tidy/src/walk.rs b/src/tools/tidy/src/walk.rs
index b07e80767..4cfb70fa3 100644
--- a/src/tools/tidy/src/walk.rs
+++ b/src/tools/tidy/src/walk.rs
@@ -21,6 +21,12 @@ pub fn filter_dirs(path: &Path) -> bool {
         "src/tools/rust-installer",
         "src/tools/rustfmt",
         "src/doc/book",
+        "src/doc/edition-guide",
+        "src/doc/embedded-book",
+        "src/doc/nomicon",
+        "src/doc/rust-by-example",
+        "src/doc/rustc-dev-guide",
+        "src/doc/reference",
         // Filter RLS output directories
         "target/rls",
         "src/bootstrap/target",