Merge remote-tracking branch 'upstream/master' into rustup

1 files changed, 277 insertions, 833 deletions

diff --git a/clippy_dev/src/update_lints.rs b/clippy_dev/src/update_lints.rs
index d848a97f86d..0c861b72935 100644
--- a/clippy_dev/src/update_lints.rs
+++ b/clippy_dev/src/update_lints.rs
@@ -1,15 +1,12 @@
-use crate::utils::{UpdateMode, clippy_project_root, exit_with_failure, replace_region_in_file};
-use aho_corasick::AhoCorasickBuilder;
+use crate::utils::{
+    File, FileAction, FileUpdater, RustSearcher, Token, UpdateMode, UpdateStatus, panic_file, update_text_region_fn,
+};
 use itertools::Itertools;
-use rustc_lexer::{LiteralKind, TokenKind, tokenize};
-use rustc_literal_escaper::{Mode, unescape_unicode};
-use std::collections::{HashMap, HashSet};
-use std::ffi::OsStr;
-use std::fmt::{self, Write};
-use std::fs::{self, OpenOptions};
-use std::io::{self, Read, Seek, Write as _};
+use std::collections::HashSet;
+use std::fmt::Write;
+use std::fs::OpenOptions;
 use std::ops::Range;
-use std::path::{Path, PathBuf};
+use std::path::Path;
 use walkdir::{DirEntry, WalkDir};
 
 const GENERATED_FILE_COMMENT: &str = "// This file was generated by `cargo dev update_lints`.\n\
@@ -28,839 +25,322 @@ const DOCS_LINK: &str = "https://rust-lang.github.io/rust-clippy/master/index.ht
 ///
 /// Panics if a file path could not read from or then written to
 pub fn update(update_mode: UpdateMode) {
-    let (lints, deprecated_lints, renamed_lints) = gather_all();
-    generate_lint_files(update_mode, &lints, &deprecated_lints, &renamed_lints);
+    let lints = find_lint_decls();
+    let DeprecatedLints {
+        renamed, deprecated, ..
+    } = read_deprecated_lints();
+    generate_lint_files(update_mode, &lints, &deprecated, &renamed);
 }
 
-fn generate_lint_files(
+pub fn generate_lint_files(
     update_mode: UpdateMode,
     lints: &[Lint],
-    deprecated_lints: &[DeprecatedLint],
-    renamed_lints: &[RenamedLint],
+    deprecated: &[DeprecatedLint],
+    renamed: &[RenamedLint],
 ) {
-    let mut lints = lints.to_owned();
-    lints.sort_by_key(|lint| lint.name.clone());
-
-    replace_region_in_file(
-        update_mode,
-        Path::new("README.md"),
-        "[There are over ",
-        " lints included in this crate!]",
-        |res| {
-            write!(res, "{}", round_to_fifty(lints.len())).unwrap();
-        },
-    );
-
-    replace_region_in_file(
-        update_mode,
-        Path::new("book/src/README.md"),
-        "[There are over ",
-        " lints included in this crate!]",
-        |res| {
-            write!(res, "{}", round_to_fifty(lints.len())).unwrap();
-        },
-    );
-
-    replace_region_in_file(
-        update_mode,
-        Path::new("CHANGELOG.md"),
-        "<!-- begin autogenerated links to lint list -->\n",
-        "<!-- end autogenerated links to lint list -->",
-        |res| {
-            for lint in lints
-                .iter()
-                .map(|l| &*l.name)
-                .chain(deprecated_lints.iter().filter_map(|l| l.name.strip_prefix("clippy::")))
-                .chain(renamed_lints.iter().filter_map(|l| l.old_name.strip_prefix("clippy::")))
-                .sorted()
-            {
-                writeln!(res, "[`{lint}`]: {DOCS_LINK}#{lint}").unwrap();
-            }
-        },
-    );
-
-    // This has to be in lib.rs, otherwise rustfmt doesn't work
-    replace_region_in_file(
-        update_mode,
-        Path::new("clippy_lints/src/lib.rs"),
-        "// begin lints modules, do not remove this comment, it’s used in `update_lints`\n",
-        "// end lints modules, do not remove this comment, it’s used in `update_lints`",
-        |res| {
-            for lint_mod in lints.iter().map(|l| &l.module).unique().sorted() {
-                writeln!(res, "mod {lint_mod};").unwrap();
-            }
-        },
-    );
-
-    process_file(
-        "clippy_lints/src/declared_lints.rs",
+    FileUpdater::default().update_files_checked(
+        "cargo dev update_lints",
         update_mode,
-        &gen_declared_lints(lints.iter()),
-    );
-
-    let content = gen_deprecated_lints_test(deprecated_lints);
-    process_file("tests/ui/deprecated.rs", update_mode, &content);
-
-    let content = gen_renamed_lints_test(renamed_lints);
-    process_file("tests/ui/rename.rs", update_mode, &content);
-}
-
-pub fn print_lints() {
-    let (lints, _, _) = gather_all();
-    let lint_count = lints.len();
-    let grouped_by_lint_group = Lint::by_lint_group(lints.into_iter());
-
-    for (lint_group, mut lints) in grouped_by_lint_group {
-        println!("\n## {lint_group}");
-
-        lints.sort_by_key(|l| l.name.clone());
-
-        for lint in lints {
-            println!("* [{}]({DOCS_LINK}#{}) ({})", lint.name, lint.name, lint.desc);
-        }
-    }
-
-    println!("there are {lint_count} lints");
-}
-
-/// Runs the `rename_lint` command.
-///
-/// This does the following:
-/// * Adds an entry to `renamed_lints.rs`.
-/// * Renames all lint attributes to the new name (e.g. `#[allow(clippy::lint_name)]`).
-/// * Renames the lint struct to the new name.
-/// * Renames the module containing the lint struct to the new name if it shares a name with the
-///   lint.
-///
-/// # Panics
-/// Panics for the following conditions:
-/// * If a file path could not read from or then written to
-/// * If either lint name has a prefix
-/// * If `old_name` doesn't name an existing lint.
-/// * If `old_name` names a deprecated or renamed lint.
-#[allow(clippy::too_many_lines)]
-pub fn rename(old_name: &str, new_name: &str, uplift: bool) {
-    if let Some((prefix, _)) = old_name.split_once("::") {
-        panic!("`{old_name}` should not contain the `{prefix}` prefix");
-    }
-    if let Some((prefix, _)) = new_name.split_once("::") {
-        panic!("`{new_name}` should not contain the `{prefix}` prefix");
-    }
-
-    let (mut lints, deprecated_lints, mut renamed_lints) = gather_all();
-    let mut old_lint_index = None;
-    let mut found_new_name = false;
-    for (i, lint) in lints.iter().enumerate() {
-        if lint.name == old_name {
-            old_lint_index = Some(i);
-        } else if lint.name == new_name {
-            found_new_name = true;
-        }
-    }
-    let old_lint_index = old_lint_index.unwrap_or_else(|| panic!("could not find lint `{old_name}`"));
-
-    let lint = RenamedLint {
-        old_name: format!("clippy::{old_name}"),
-        new_name: if uplift {
-            new_name.into()
-        } else {
-            format!("clippy::{new_name}")
-        },
-    };
-
-    // Renamed lints and deprecated lints shouldn't have been found in the lint list, but check just in
-    // case.
-    assert!(
-        !renamed_lints.iter().any(|l| lint.old_name == l.old_name),
-        "`{old_name}` has already been renamed"
-    );
-    assert!(
-        !deprecated_lints.iter().any(|l| lint.old_name == l.name),
-        "`{old_name}` has already been deprecated"
-    );
-
-    // Update all lint level attributes. (`clippy::lint_name`)
-    for file in WalkDir::new(clippy_project_root())
-        .into_iter()
-        .map(Result::unwrap)
-        .filter(|f| {
-            let name = f.path().file_name();
-            let ext = f.path().extension();
-            (ext == Some(OsStr::new("rs")) || ext == Some(OsStr::new("fixed")))
-                && name != Some(OsStr::new("rename.rs"))
-                && name != Some(OsStr::new("deprecated_lints.rs"))
-        })
-    {
-        rewrite_file(file.path(), |s| {
-            replace_ident_like(s, &[(&lint.old_name, &lint.new_name)])
-        });
-    }
-
-    let version = crate::new_lint::get_stabilization_version();
-    rewrite_file(Path::new("clippy_lints/src/deprecated_lints.rs"), |s| {
-        insert_at_marker(
-            s,
-            "// end renamed lints. used by `cargo dev rename_lint`",
-            &format!(
-                "#[clippy::version = \"{version}\"]\n    \
-                (\"{}\", \"{}\"),\n    ",
-                lint.old_name, lint.new_name,
+        &mut [
+            (
+                "README.md",
+                &mut update_text_region_fn("[There are over ", " lints included in this crate!]", |dst| {
+                    write!(dst, "{}", round_to_fifty(lints.len())).unwrap();
+                }),
             ),
-        )
-    });
-
-    renamed_lints.push(lint);
-    renamed_lints.sort_by(|lhs, rhs| {
-        lhs.new_name
-            .starts_with("clippy::")
-            .cmp(&rhs.new_name.starts_with("clippy::"))
-            .reverse()
-            .then_with(|| lhs.old_name.cmp(&rhs.old_name))
-    });
-
-    if uplift {
-        write_file(Path::new("tests/ui/rename.rs"), &gen_renamed_lints_test(&renamed_lints));
-        println!(
-            "`{old_name}` has be uplifted. All the code inside `clippy_lints` related to it needs to be removed manually."
-        );
-    } else if found_new_name {
-        write_file(Path::new("tests/ui/rename.rs"), &gen_renamed_lints_test(&renamed_lints));
-        println!(
-            "`{new_name}` is already defined. The old linting code inside `clippy_lints` needs to be updated/removed manually."
-        );
-    } else {
-        // Rename the lint struct and source files sharing a name with the lint.
-        let lint = &mut lints[old_lint_index];
-        let old_name_upper = old_name.to_uppercase();
-        let new_name_upper = new_name.to_uppercase();
-        lint.name = new_name.into();
-
-        // Rename test files. only rename `.stderr` and `.fixed` files if the new test name doesn't exist.
-        if try_rename_file(
-            Path::new(&format!("tests/ui/{old_name}.rs")),
-            Path::new(&format!("tests/ui/{new_name}.rs")),
-        ) {
-            try_rename_file(
-                Path::new(&format!("tests/ui/{old_name}.stderr")),
-                Path::new(&format!("tests/ui/{new_name}.stderr")),
-            );
-            try_rename_file(
-                Path::new(&format!("tests/ui/{old_name}.fixed")),
-                Path::new(&format!("tests/ui/{new_name}.fixed")),
-            );
-        }
-
-        // Try to rename the file containing the lint if the file name matches the lint's name.
-        let replacements;
-        let replacements = if lint.module == old_name
-            && try_rename_file(
-                Path::new(&format!("clippy_lints/src/{old_name}.rs")),
-                Path::new(&format!("clippy_lints/src/{new_name}.rs")),
-            ) {
-            // Edit the module name in the lint list. Note there could be multiple lints.
-            for lint in lints.iter_mut().filter(|l| l.module == old_name) {
-                lint.module = new_name.into();
-            }
-            replacements = [(&*old_name_upper, &*new_name_upper), (old_name, new_name)];
-            replacements.as_slice()
-        } else if !lint.module.contains("::")
-            // Catch cases like `methods/lint_name.rs` where the lint is stored in `methods/mod.rs`
-            && try_rename_file(
-                Path::new(&format!("clippy_lints/src/{}/{old_name}.rs", lint.module)),
-                Path::new(&format!("clippy_lints/src/{}/{new_name}.rs", lint.module)),
-            )
-        {
-            // Edit the module name in the lint list. Note there could be multiple lints, or none.
-            let renamed_mod = format!("{}::{old_name}", lint.module);
-            for lint in lints.iter_mut().filter(|l| l.module == renamed_mod) {
-                lint.module = format!("{}::{new_name}", lint.module);
-            }
-            replacements = [(&*old_name_upper, &*new_name_upper), (old_name, new_name)];
-            replacements.as_slice()
-        } else {
-            replacements = [(&*old_name_upper, &*new_name_upper), ("", "")];
-            &replacements[0..1]
-        };
-
-        // Don't change `clippy_utils/src/renamed_lints.rs` here as it would try to edit the lint being
-        // renamed.
-        for (_, file) in clippy_lints_src_files().filter(|(rel_path, _)| rel_path != OsStr::new("deprecated_lints.rs"))
-        {
-            rewrite_file(file.path(), |s| replace_ident_like(s, replacements));
-        }
-
-        generate_lint_files(UpdateMode::Change, &lints, &deprecated_lints, &renamed_lints);
-        println!("{old_name} has been successfully renamed");
-    }
-
-    println!("note: `cargo uitest` still needs to be run to update the test results");
-}
-
-/// Runs the `deprecate` command
-///
-/// This does the following:
-/// * Adds an entry to `deprecated_lints.rs`.
-/// * Removes the lint declaration (and the entire file if applicable)
-///
-/// # Panics
-///
-/// If a file path could not read from or written to
-pub fn deprecate(name: &str, reason: &str) {
-    let prefixed_name = if name.starts_with("clippy::") {
-        name.to_owned()
-    } else {
-        format!("clippy::{name}")
-    };
-    let stripped_name = &prefixed_name[8..];
-
-    let (mut lints, mut deprecated_lints, renamed_lints) = gather_all();
-    let Some(lint) = lints.iter().find(|l| l.name == stripped_name) else {
-        eprintln!("error: failed to find lint `{name}`");
-        return;
-    };
-
-    let mod_path = {
-        let mut mod_path = PathBuf::from(format!("clippy_lints/src/{}", lint.module));
-        if mod_path.is_dir() {
-            mod_path = mod_path.join("mod");
-        }
-
-        mod_path.set_extension("rs");
-        mod_path
-    };
-
-    let deprecated_lints_path = &*clippy_project_root().join("clippy_lints/src/deprecated_lints.rs");
-
-    if remove_lint_declaration(stripped_name, &mod_path, &mut lints).unwrap_or(false) {
-        let version = crate::new_lint::get_stabilization_version();
-        rewrite_file(deprecated_lints_path, |s| {
-            insert_at_marker(
-                s,
-                "// end deprecated lints. used by `cargo dev deprecate_lint`",
-                &format!("#[clippy::version = \"{version}\"]\n    (\"{prefixed_name}\", \"{reason}\"),\n    ",),
-            )
-        });
-
-        deprecated_lints.push(DeprecatedLint {
-            name: prefixed_name,
-            reason: reason.into(),
-        });
-
-        generate_lint_files(UpdateMode::Change, &lints, &deprecated_lints, &renamed_lints);
-        println!("info: `{name}` has successfully been deprecated");
-        println!("note: you must run `cargo uitest` to update the test results");
-    } else {
-        eprintln!("error: lint not found");
-    }
-}
-
-fn remove_lint_declaration(name: &str, path: &Path, lints: &mut Vec<Lint>) -> io::Result<bool> {
-    fn remove_lint(name: &str, lints: &mut Vec<Lint>) {
-        lints.iter().position(|l| l.name == name).map(|pos| lints.remove(pos));
-    }
-
-    fn remove_test_assets(name: &str) {
-        let test_file_stem = format!("tests/ui/{name}");
-        let path = Path::new(&test_file_stem);
-
-        // Some lints have their own directories, delete them
-        if path.is_dir() {
-            let _ = fs::remove_dir_all(path);
-            return;
-        }
-
-        // Remove all related test files
-        let _ = fs::remove_file(path.with_extension("rs"));
-        let _ = fs::remove_file(path.with_extension("stderr"));
-        let _ = fs::remove_file(path.with_extension("fixed"));
-    }
-
-    fn remove_impl_lint_pass(lint_name_upper: &str, content: &mut String) {
-        let impl_lint_pass_start = content.find("impl_lint_pass!").unwrap_or_else(|| {
-            content
-                .find("declare_lint_pass!")
-                .unwrap_or_else(|| panic!("failed to find `impl_lint_pass`"))
-        });
-        let mut impl_lint_pass_end = content[impl_lint_pass_start..]
-            .find(']')
-            .expect("failed to find `impl_lint_pass` terminator");
-
-        impl_lint_pass_end += impl_lint_pass_start;
-        if let Some(lint_name_pos) = content[impl_lint_pass_start..impl_lint_pass_end].find(lint_name_upper) {
-            let mut lint_name_end = impl_lint_pass_start + (lint_name_pos + lint_name_upper.len());
-            for c in content[lint_name_end..impl_lint_pass_end].chars() {
-                // Remove trailing whitespace
-                if c == ',' || c.is_whitespace() {
-                    lint_name_end += 1;
-                } else {
-                    break;
+            (
+                "book/src/README.md",
+                &mut update_text_region_fn("[There are over ", " lints included in this crate!]", |dst| {
+                    write!(dst, "{}", round_to_fifty(lints.len())).unwrap();
+                }),
+            ),
+            (
+                "CHANGELOG.md",
+                &mut update_text_region_fn(
+                    "<!-- begin autogenerated links to lint list -->\n",
+                    "<!-- end autogenerated links to lint list -->",
+                    |dst| {
+                        for lint in lints
+                            .iter()
+                            .map(|l| &*l.name)
+                            .chain(deprecated.iter().filter_map(|l| l.name.strip_prefix("clippy::")))
+                            .chain(renamed.iter().filter_map(|l| l.old_name.strip_prefix("clippy::")))
+                            .sorted()
+                        {
+                            writeln!(dst, "[`{lint}`]: {DOCS_LINK}#{lint}").unwrap();
+                        }
+                    },
+                ),
+            ),
+            (
+                "clippy_lints/src/lib.rs",
+                &mut update_text_region_fn(
+                    "// begin lints modules, do not remove this comment, it’s used in `update_lints`\n",
+                    "// end lints modules, do not remove this comment, it’s used in `update_lints`",
+                    |dst| {
+                        for lint_mod in lints.iter().map(|l| &l.module).sorted().dedup() {
+                            writeln!(dst, "mod {lint_mod};").unwrap();
+                        }
+                    },
+                ),
+            ),
+            ("clippy_lints/src/declared_lints.rs", &mut |_, src, dst| {
+                dst.push_str(GENERATED_FILE_COMMENT);
+                dst.push_str("pub static LINTS: &[&crate::LintInfo] = &[\n");
+                for (module_name, lint_name) in lints.iter().map(|l| (&l.module, l.name.to_uppercase())).sorted() {
+                    writeln!(dst, "    crate::{module_name}::{lint_name}_INFO,").unwrap();
                 }
-            }
-
-            content.replace_range(impl_lint_pass_start + lint_name_pos..lint_name_end, "");
-        }
-    }
-
-    if path.exists()
-        && let Some(lint) = lints.iter().find(|l| l.name == name)
-    {
-        if lint.module == name {
-            // The lint name is the same as the file, we can just delete the entire file
-            fs::remove_file(path)?;
-        } else {
-            // We can't delete the entire file, just remove the declaration
-
-            if let Some(Some("mod.rs")) = path.file_name().map(OsStr::to_str) {
-                // Remove clippy_lints/src/some_mod/some_lint.rs
-                let mut lint_mod_path = path.to_path_buf();
-                lint_mod_path.set_file_name(name);
-                lint_mod_path.set_extension("rs");
-
-                let _ = fs::remove_file(lint_mod_path);
-            }
-
-            let mut content =
-                fs::read_to_string(path).unwrap_or_else(|_| panic!("failed to read `{}`", path.to_string_lossy()));
-
-            eprintln!(
-                "warn: you will have to manually remove any code related to `{name}` from `{}`",
-                path.display()
-            );
-
-            assert!(
-                content[lint.declaration_range.clone()].contains(&name.to_uppercase()),
-                "error: `{}` does not contain lint `{}`'s declaration",
-                path.display(),
-                lint.name
-            );
-
-            // Remove lint declaration (declare_clippy_lint!)
-            content.replace_range(lint.declaration_range.clone(), "");
-
-            // Remove the module declaration (mod xyz;)
-            let mod_decl = format!("\nmod {name};");
-            content = content.replacen(&mod_decl, "", 1);
-
-            remove_impl_lint_pass(&lint.name.to_uppercase(), &mut content);
-            fs::write(path, content).unwrap_or_else(|_| panic!("failed to write to `{}`", path.to_string_lossy()));
-        }
-
-        remove_test_assets(name);
-        remove_lint(name, lints);
-        return Ok(true);
-    }
-
-    Ok(false)
-}
-
-/// Replace substrings if they aren't bordered by identifier characters. Returns `None` if there
-/// were no replacements.
-fn replace_ident_like(contents: &str, replacements: &[(&str, &str)]) -> Option<String> {
-    fn is_ident_char(c: u8) -> bool {
-        matches!(c, b'a'..=b'z' | b'A'..=b'Z' | b'0'..=b'9' | b'_')
-    }
-
-    let searcher = AhoCorasickBuilder::new()
-        .match_kind(aho_corasick::MatchKind::LeftmostLongest)
-        .build(replacements.iter().map(|&(x, _)| x.as_bytes()))
-        .unwrap();
-
-    let mut result = String::with_capacity(contents.len() + 1024);
-    let mut pos = 0;
-    let mut edited = false;
-    for m in searcher.find_iter(contents) {
-        let (old, new) = replacements[m.pattern()];
-        result.push_str(&contents[pos..m.start()]);
-        result.push_str(
-            if !is_ident_char(contents.as_bytes().get(m.start().wrapping_sub(1)).copied().unwrap_or(0))
-                && !is_ident_char(contents.as_bytes().get(m.end()).copied().unwrap_or(0))
-            {
-                edited = true;
-                new
-            } else {
-                old
-            },
-        );
-        pos = m.end();
-    }
-    result.push_str(&contents[pos..]);
-    edited.then_some(result)
+                dst.push_str("];\n");
+                UpdateStatus::from_changed(src != dst)
+            }),
+            ("tests/ui/deprecated.rs", &mut |_, src, dst| {
+                dst.push_str(GENERATED_FILE_COMMENT);
+                for lint in deprecated {
+                    writeln!(dst, "#![warn({})] //~ ERROR: lint `{}`", lint.name, lint.name).unwrap();
+                }
+                dst.push_str("\nfn main() {}\n");
+                UpdateStatus::from_changed(src != dst)
+            }),
+            ("tests/ui/rename.rs", &mut gen_renamed_lints_test_fn(renamed)),
+        ],
+    );
 }
 
 fn round_to_fifty(count: usize) -> usize {
     count / 50 * 50
 }
 
-fn process_file(path: impl AsRef<Path>, update_mode: UpdateMode, content: &str) {
-    if update_mode == UpdateMode::Check {
-        let old_content =
-            fs::read_to_string(&path).unwrap_or_else(|e| panic!("Cannot read from {}: {e}", path.as_ref().display()));
-        if content != old_content {
-            exit_with_failure();
-        }
-    } else {
-        fs::write(&path, content.as_bytes())
-            .unwrap_or_else(|e| panic!("Cannot write to {}: {e}", path.as_ref().display()));
-    }
-}
-
 /// Lint data parsed from the Clippy source code.
 #[derive(Clone, PartialEq, Eq, Debug)]
-struct Lint {
-    name: String,
-    group: String,
-    desc: String,
-    module: String,
-    declaration_range: Range<usize>,
-}
-
-impl Lint {
-    #[must_use]
-    fn new(name: &str, group: &str, desc: &str, module: &str, declaration_range: Range<usize>) -> Self {
-        Self {
-            name: name.to_lowercase(),
-            group: group.into(),
-            desc: remove_line_splices(desc),
-            module: module.into(),
-            declaration_range,
-        }
-    }
-
-    /// Returns the lints in a `HashMap`, grouped by the different lint groups
-    #[must_use]
-    fn by_lint_group(lints: impl Iterator<Item = Self>) -> HashMap<String, Vec<Self>> {
-        lints.map(|lint| (lint.group.to_string(), lint)).into_group_map()
-    }
+pub struct Lint {
+    pub name: String,
+    pub group: String,
+    pub module: String,
+    pub declaration_range: Range<usize>,
 }
 
 #[derive(Clone, PartialEq, Eq, Debug)]
-struct DeprecatedLint {
-    name: String,
-    reason: String,
-}
-impl DeprecatedLint {
-    fn new(name: &str, reason: &str) -> Self {
-        Self {
-            name: remove_line_splices(name),
-            reason: remove_line_splices(reason),
-        }
-    }
+pub struct DeprecatedLint {
+    pub name: String,
+    pub reason: String,
 }
 
-struct RenamedLint {
-    old_name: String,
-    new_name: String,
-}
-impl RenamedLint {
-    fn new(old_name: &str, new_name: &str) -> Self {
-        Self {
-            old_name: remove_line_splices(old_name),
-            new_name: remove_line_splices(new_name),
-        }
-    }
+pub struct RenamedLint {
+    pub old_name: String,
+    pub new_name: String,
 }
 
-/// Generates the code for registering lints
-#[must_use]
-fn gen_declared_lints<'a>(lints: impl Iterator<Item = &'a Lint>) -> String {
-    let mut details: Vec<_> = lints.map(|l| (&l.module, l.name.to_uppercase())).collect();
-    details.sort_unstable();
-
-    let mut output = GENERATED_FILE_COMMENT.to_string();
-    output.push_str("pub static LINTS: &[&crate::LintInfo] = &[\n");
-
-    for (module_name, lint_name) in details {
-        let _: fmt::Result = writeln!(output, "    crate::{module_name}::{lint_name}_INFO,");
-    }
-    output.push_str("];\n");
-
-    output
-}
-
-fn gen_deprecated_lints_test(lints: &[DeprecatedLint]) -> String {
-    let mut res: String = GENERATED_FILE_COMMENT.into();
-    for lint in lints {
-        writeln!(res, "#![warn({})] //~ ERROR: lint `{}`", lint.name, lint.name).unwrap();
-    }
-    res.push_str("\nfn main() {}\n");
-    res
-}
-
-fn gen_renamed_lints_test(lints: &[RenamedLint]) -> String {
-    let mut seen_lints = HashSet::new();
-    let mut res: String = GENERATED_FILE_COMMENT.into();
-
-    res.push_str("#![allow(clippy::duplicated_attributes)]\n");
-    for lint in lints {
-        if seen_lints.insert(&lint.new_name) {
-            writeln!(res, "#![allow({})]", lint.new_name).unwrap();
+pub fn gen_renamed_lints_test_fn(lints: &[RenamedLint]) -> impl Fn(&Path, &str, &mut String) -> UpdateStatus {
+    move |_, src, dst| {
+        let mut seen_lints = HashSet::new();
+        dst.push_str(GENERATED_FILE_COMMENT);
+        dst.push_str("#![allow(clippy::duplicated_attributes)]\n");
+        for lint in lints {
+            if seen_lints.insert(&lint.new_name) {
+                writeln!(dst, "#![allow({})]", lint.new_name).unwrap();
+            }
         }
-    }
-    seen_lints.clear();
-    for lint in lints {
-        if seen_lints.insert(&lint.old_name) {
-            writeln!(res, "#![warn({})] //~ ERROR: lint `{}`", lint.old_name, lint.old_name).unwrap();
+        seen_lints.clear();
+        for lint in lints {
+            if seen_lints.insert(&lint.old_name) {
+                writeln!(dst, "#![warn({})] //~ ERROR: lint `{}`", lint.old_name, lint.old_name).unwrap();
+            }
         }
+        dst.push_str("\nfn main() {}\n");
+        UpdateStatus::from_changed(src != dst)
     }
-    res.push_str("\nfn main() {}\n");
-    res
 }
 
-/// Gathers all lints defined in `clippy_lints/src`
-fn gather_all() -> (Vec<Lint>, Vec<DeprecatedLint>, Vec<RenamedLint>) {
+/// Finds all lint declarations (`declare_clippy_lint!`)
+#[must_use]
+pub fn find_lint_decls() -> Vec<Lint> {
     let mut lints = Vec::with_capacity(1000);
-    let mut deprecated_lints = Vec::with_capacity(50);
-    let mut renamed_lints = Vec::with_capacity(50);
-
-    for (rel_path, file) in clippy_lints_src_files() {
-        let path = file.path();
-        let contents =
-            fs::read_to_string(path).unwrap_or_else(|e| panic!("Cannot read from `{}`: {e}", path.display()));
-        let module = rel_path
-            .components()
-            .map(|c| c.as_os_str().to_str().unwrap())
-            .collect::<Vec<_>>()
-            .join("::");
+    let mut contents = String::new();
+    for (file, module) in read_src_with_module("clippy_lints/src".as_ref()) {
+        parse_clippy_lint_decls(
+            File::open_read_to_cleared_string(file.path(), &mut contents),
+            &module,
+            &mut lints,
+        );
+    }
+    lints.sort_by(|lhs, rhs| lhs.name.cmp(&rhs.name));
+    lints
+}
 
-        // If the lints are stored in mod.rs, we get the module name from
-        // the containing directory:
-        let module = if let Some(module) = module.strip_suffix("::mod.rs") {
-            module
-        } else {
-            module.strip_suffix(".rs").unwrap_or(&module)
+/// Reads the source files from the given root directory
+fn read_src_with_module(src_root: &Path) -> impl use<'_> + Iterator<Item = (DirEntry, String)> {
+    WalkDir::new(src_root).into_iter().filter_map(move |e| {
+        let e = match e {
+            Ok(e) => e,
+            Err(ref e) => panic_file(e, FileAction::Read, src_root),
         };
-
-        if module == "deprecated_lints" {
-            parse_deprecated_contents(&contents, &mut deprecated_lints, &mut renamed_lints);
+        let path = e.path().as_os_str().as_encoded_bytes();
+        if let Some(path) = path.strip_suffix(b".rs")
+            && let Some(path) = path.get("clippy_lints/src/".len()..)
+        {
+            if path == b"lib" {
+                Some((e, String::new()))
+            } else {
+                let path = if let Some(path) = path.strip_suffix(b"mod")
+                    && let Some(path) = path.strip_suffix(b"/").or_else(|| path.strip_suffix(b"\\"))
+                {
+                    path
+                } else {
+                    path
+                };
+                if let Ok(path) = str::from_utf8(path) {
+                    let path = path.replace(['/', '\\'], "::");
+                    Some((e, path))
+                } else {
+                    None
+                }
+            }
         } else {
-            parse_contents(&contents, module, &mut lints);
+            None
         }
-    }
-    (lints, deprecated_lints, renamed_lints)
-}
-
-fn clippy_lints_src_files() -> impl Iterator<Item = (PathBuf, DirEntry)> {
-    let root_path = clippy_project_root().join("clippy_lints/src");
-    let iter = WalkDir::new(&root_path).into_iter();
-    iter.map(Result::unwrap)
-        .filter(|f| f.path().extension() == Some(OsStr::new("rs")))
-        .map(move |f| (f.path().strip_prefix(&root_path).unwrap().to_path_buf(), f))
+    })
 }
 
-macro_rules! match_tokens {
-    ($iter:ident, $($token:ident $({$($fields:tt)*})? $(($capture:ident))?)*) => {
-         {
-            $(#[allow(clippy::redundant_pattern)] let Some(LintDeclSearchResult {
-                    token_kind: TokenKind::$token $({$($fields)*})?,
-                    content: $($capture @)? _,
-                    ..
-            }) = $iter.next() else {
-                continue;
-            };)*
-            #[allow(clippy::unused_unit)]
-            { ($($($capture,)?)*) }
+/// Parse a source file looking for `declare_clippy_lint` macro invocations.
+fn parse_clippy_lint_decls(contents: &str, module: &str, lints: &mut Vec<Lint>) {
+    #[allow(clippy::enum_glob_use)]
+    use Token::*;
+    #[rustfmt::skip]
+    static DECL_TOKENS: &[Token] = &[
+        // !{ /// docs
+        Bang, OpenBrace, AnyDoc,
+        // #[clippy::version = "version"]
+        Pound, OpenBracket, Ident("clippy"), DoubleColon, Ident("version"), Eq, LitStr, CloseBracket,
+        // pub NAME, GROUP,
+        Ident("pub"), CaptureIdent, Comma, CaptureIdent, Comma,
+    ];
+
+    let mut searcher = RustSearcher::new(contents);
+    while searcher.find_token(Ident("declare_clippy_lint")) {
+        let start = searcher.pos() as usize - "declare_clippy_lint".len();
+        let (mut name, mut group) = ("", "");
+        if searcher.match_tokens(DECL_TOKENS, &mut [&mut name, &mut group]) && searcher.find_token(CloseBrace) {
+            lints.push(Lint {
+                name: name.to_lowercase(),
+                group: group.into(),
+                module: module.into(),
+                declaration_range: start..searcher.pos() as usize,
+            });
         }
     }
 }
 
-pub(crate) use match_tokens;
-
-pub(crate) struct LintDeclSearchResult<'a> {
-    pub token_kind: TokenKind,
-    pub content: &'a str,
-    pub range: Range<usize>,
+pub struct DeprecatedLints {
+    pub file: File<'static>,
+    pub contents: String,
+    pub deprecated: Vec<DeprecatedLint>,
+    pub renamed: Vec<RenamedLint>,
+    pub deprecated_end: u32,
+    pub renamed_end: u32,
 }
 
-/// Parse a source file looking for `declare_clippy_lint` macro invocations.
-fn parse_contents(contents: &str, module: &str, lints: &mut Vec<Lint>) {
-    let mut offset = 0usize;
-    let mut iter = tokenize(contents).map(|t| {
-        let range = offset..offset + t.len as usize;
-        offset = range.end;
-
-        LintDeclSearchResult {
-            token_kind: t.kind,
-            content: &contents[range.clone()],
-            range,
-        }
-    });
-
-    while let Some(LintDeclSearchResult { range, .. }) = iter.find(
-        |LintDeclSearchResult {
-             token_kind, content, ..
-         }| token_kind == &TokenKind::Ident && *content == "declare_clippy_lint",
-    ) {
-        let start = range.start;
-        let mut iter = iter
-            .by_ref()
-            .filter(|t| !matches!(t.token_kind, TokenKind::Whitespace | TokenKind::LineComment { .. }));
-        // matches `!{`
-        match_tokens!(iter, Bang OpenBrace);
-        match iter.next() {
-            // #[clippy::version = "version"] pub
-            Some(LintDeclSearchResult {
-                token_kind: TokenKind::Pound,
-                ..
-            }) => {
-                match_tokens!(iter, OpenBracket Ident Colon Colon Ident Eq Literal{..} CloseBracket Ident);
-            },
-            // pub
-            Some(LintDeclSearchResult {
-                token_kind: TokenKind::Ident,
-                ..
-            }) => (),
-            _ => continue,
-        }
-
-        let (name, group, desc) = match_tokens!(
-            iter,
-            // LINT_NAME
-            Ident(name) Comma
-            // group,
-            Ident(group) Comma
-            // "description"
-            Literal{..}(desc)
-        );
-
-        if let Some(end) = iter.find_map(|t| {
-            if let LintDeclSearchResult {
-                token_kind: TokenKind::CloseBrace,
-                range,
-                ..
-            } = t
-            {
-                Some(range.end)
-            } else {
-                None
-            }
-        }) {
-            lints.push(Lint::new(name, group, desc, module, start..end));
-        }
-    }
-}
-
-/// Parse a source file looking for `declare_deprecated_lint` macro invocations.
-fn parse_deprecated_contents(contents: &str, deprecated: &mut Vec<DeprecatedLint>, renamed: &mut Vec<RenamedLint>) {
-    let Some((_, contents)) = contents.split_once("\ndeclare_with_version! { DEPRECATED") else {
-        return;
-    };
-    let Some((deprecated_src, renamed_src)) = contents.split_once("\ndeclare_with_version! { RENAMED") else {
-        return;
+#[must_use]
+pub fn read_deprecated_lints() -> DeprecatedLints {
+    #[allow(clippy::enum_glob_use)]
+    use Token::*;
+    #[rustfmt::skip]
+    static DECL_TOKENS: &[Token] = &[
+        // #[clippy::version = "version"]
+        Pound, OpenBracket, Ident("clippy"), DoubleColon, Ident("version"), Eq, LitStr, CloseBracket,
+        // ("first", "second"),
+        OpenParen, CaptureLitStr, Comma, CaptureLitStr, CloseParen, Comma,
+    ];
+    #[rustfmt::skip]
+    static DEPRECATED_TOKENS: &[Token] = &[
+        // !{ DEPRECATED(DEPRECATED_VERSION) = [
+        Bang, OpenBrace, Ident("DEPRECATED"), OpenParen, Ident("DEPRECATED_VERSION"), CloseParen, Eq, OpenBracket,
+    ];
+    #[rustfmt::skip]
+    static RENAMED_TOKENS: &[Token] = &[
+        // !{ RENAMED(RENAMED_VERSION) = [
+        Bang, OpenBrace, Ident("RENAMED"), OpenParen, Ident("RENAMED_VERSION"), CloseParen, Eq, OpenBracket,
+    ];
+
+    let path = "clippy_lints/src/deprecated_lints.rs";
+    let mut res = DeprecatedLints {
+        file: File::open(path, OpenOptions::new().read(true).write(true)),
+        contents: String::new(),
+        deprecated: Vec::with_capacity(30),
+        renamed: Vec::with_capacity(80),
+        deprecated_end: 0,
+        renamed_end: 0,
     };
 
-    for line in deprecated_src.lines() {
-        let mut offset = 0usize;
-        let mut iter = tokenize(line).map(|t| {
-            let range = offset..offset + t.len as usize;
-            offset = range.end;
+    res.file.read_append_to_string(&mut res.contents);
+    let mut searcher = RustSearcher::new(&res.contents);
 
-            LintDeclSearchResult {
-                token_kind: t.kind,
-                content: &line[range.clone()],
-                range,
-            }
-        });
+    // First instance is the macro definition.
+    assert!(
+        searcher.find_token(Ident("declare_with_version")),
+        "error reading deprecated lints"
+    );
 
-        let (name, reason) = match_tokens!(
-            iter,
-            // ("old_name",
-            Whitespace OpenParen Literal{kind: LiteralKind::Str{..},..}(name) Comma
-            // "new_name"),
-            Whitespace Literal{kind: LiteralKind::Str{..},..}(reason) CloseParen Comma
-        );
-        deprecated.push(DeprecatedLint::new(name, reason));
+    if searcher.find_token(Ident("declare_with_version")) && searcher.match_tokens(DEPRECATED_TOKENS, &mut []) {
+        let mut name = "";
+        let mut reason = "";
+        while searcher.match_tokens(DECL_TOKENS, &mut [&mut name, &mut reason]) {
+            res.deprecated.push(DeprecatedLint {
+                name: parse_str_single_line(path.as_ref(), name),
+                reason: parse_str_single_line(path.as_ref(), reason),
+            });
+        }
+    } else {
+        panic!("error reading deprecated lints");
+    }
+    // position of the closing `]}` of `declare_with_version`
+    res.deprecated_end = searcher.pos();
+
+    if searcher.find_token(Ident("declare_with_version")) && searcher.match_tokens(RENAMED_TOKENS, &mut []) {
+        let mut old_name = "";
+        let mut new_name = "";
+        while searcher.match_tokens(DECL_TOKENS, &mut [&mut old_name, &mut new_name]) {
+            res.renamed.push(RenamedLint {
+                old_name: parse_str_single_line(path.as_ref(), old_name),
+                new_name: parse_str_single_line(path.as_ref(), new_name),
+            });
+        }
+    } else {
+        panic!("error reading renamed lints");
     }
-    for line in renamed_src.lines() {
-        let mut offset = 0usize;
-        let mut iter = tokenize(line).map(|t| {
-            let range = offset..offset + t.len as usize;
-            offset = range.end;
-
-            LintDeclSearchResult {
-                token_kind: t.kind,
-                content: &line[range.clone()],
-                range,
-            }
-        });
+    // position of the closing `]}` of `declare_with_version`
+    res.renamed_end = searcher.pos();
 
-        let (old_name, new_name) = match_tokens!(
-            iter,
-            // ("old_name",
-            Whitespace OpenParen Literal{kind: LiteralKind::Str{..},..}(old_name) Comma
-            // "new_name"),
-            Whitespace Literal{kind: LiteralKind::Str{..},..}(new_name) CloseParen Comma
-        );
-        renamed.push(RenamedLint::new(old_name, new_name));
-    }
+    res
 }
 
 /// Removes the line splices and surrounding quotes from a string literal
-fn remove_line_splices(s: &str) -> String {
+fn parse_str_lit(s: &str) -> String {
+    let (s, mode) = if let Some(s) = s.strip_prefix("r") {
+        (s.trim_matches('#'), rustc_literal_escaper::Mode::RawStr)
+    } else {
+        (s, rustc_literal_escaper::Mode::Str)
+    };
     let s = s
-        .strip_prefix('r')
-        .unwrap_or(s)
-        .trim_matches('#')
         .strip_prefix('"')
         .and_then(|s| s.strip_suffix('"'))
         .unwrap_or_else(|| panic!("expected quoted string, found `{s}`"));
     let mut res = String::with_capacity(s.len());
-    unescape_unicode(s, Mode::Str, &mut |range, ch| {
-        if ch.is_ok() {
-            res.push_str(&s[range]);
+    rustc_literal_escaper::unescape_unicode(s, mode, &mut |_, ch| {
+        if let Ok(ch) = ch {
+            res.push(ch);
         }
     });
     res
 }
-fn try_rename_file(old_name: &Path, new_name: &Path) -> bool {
-    match OpenOptions::new().create_new(true).write(true).open(new_name) {
-        Ok(file) => drop(file),
-        Err(e) if matches!(e.kind(), io::ErrorKind::AlreadyExists | io::ErrorKind::NotFound) => return false,
-        Err(e) => panic_file(e, new_name, "create"),
-    }
-    match fs::rename(old_name, new_name) {
-        Ok(()) => true,
-        Err(e) => {
-            drop(fs::remove_file(new_name));
-            if e.kind() == io::ErrorKind::NotFound {
-                false
-            } else {
-                panic_file(e, old_name, "rename");
-            }
-        },
-    }
-}
-
-#[allow(clippy::needless_pass_by_value)]
-fn panic_file(error: io::Error, name: &Path, action: &str) -> ! {
-    panic!("failed to {action} file `{}`: {error}", name.display())
-}
-
-fn insert_at_marker(text: &str, marker: &str, new_text: &str) -> Option<String> {
-    let i = text.find(marker)?;
-    let (pre, post) = text.split_at(i);
-    Some([pre, new_text, post].into_iter().collect())
-}
-
-fn rewrite_file(path: &Path, f: impl FnOnce(&str) -> Option<String>) {
-    let mut file = OpenOptions::new()
-        .write(true)
-        .read(true)
-        .open(path)
-        .unwrap_or_else(|e| panic_file(e, path, "open"));
-    let mut buf = String::new();
-    file.read_to_string(&mut buf)
-        .unwrap_or_else(|e| panic_file(e, path, "read"));
-    if let Some(new_contents) = f(&buf) {
-        file.rewind().unwrap_or_else(|e| panic_file(e, path, "write"));
-        file.write_all(new_contents.as_bytes())
-            .unwrap_or_else(|e| panic_file(e, path, "write"));
-        file.set_len(new_contents.len() as u64)
-            .unwrap_or_else(|e| panic_file(e, path, "write"));
-    }
-}
 
-fn write_file(path: &Path, contents: &str) {
-    fs::write(path, contents).unwrap_or_else(|e| panic_file(e, path, "write"));
+fn parse_str_single_line(path: &Path, s: &str) -> String {
+    let value = parse_str_lit(s);
+    assert!(
+        !value.contains('\n'),
+        "error parsing `{}`: `{s}` should be a single line string",
+        path.display(),
+    );
+    value
 }
 
 #[cfg(test)]
@@ -868,7 +348,7 @@ mod tests {
     use super::*;
 
     #[test]
-    fn test_parse_contents() {
+    fn test_parse_clippy_lint_decls() {
         static CONTENTS: &str = r#"
             declare_clippy_lint! {
                 #[clippy::version = "Hello Clippy!"]
@@ -886,61 +366,25 @@ mod tests {
             }
         "#;
         let mut result = Vec::new();
-        parse_contents(CONTENTS, "module_name", &mut result);
+        parse_clippy_lint_decls(CONTENTS, "module_name", &mut result);
         for r in &mut result {
             r.declaration_range = Range::default();
         }
 
         let expected = vec![
-            Lint::new(
-                "ptr_arg",
-                "style",
-                "\"really long text\"",
-                "module_name",
-                Range::default(),
-            ),
-            Lint::new(
-                "doc_markdown",
-                "pedantic",
-                "\"single line\"",
-                "module_name",
-                Range::default(),
-            ),
+            Lint {
+                name: "ptr_arg".into(),
+                group: "style".into(),
+                module: "module_name".into(),
+                declaration_range: Range::default(),
+            },
+            Lint {
+                name: "doc_markdown".into(),
+                group: "pedantic".into(),
+                module: "module_name".into(),
+                declaration_range: Range::default(),
+            },
         ];
         assert_eq!(expected, result);
     }
-
-    #[test]
-    fn test_by_lint_group() {
-        let lints = vec![
-            Lint::new("should_assert_eq", "group1", "\"abc\"", "module_name", Range::default()),
-            Lint::new(
-                "should_assert_eq2",
-                "group2",
-                "\"abc\"",
-                "module_name",
-                Range::default(),
-            ),
-            Lint::new("incorrect_match", "group1", "\"abc\"", "module_name", Range::default()),
-        ];
-        let mut expected: HashMap<String, Vec<Lint>> = HashMap::new();
-        expected.insert(
-            "group1".to_string(),
-            vec![
-                Lint::new("should_assert_eq", "group1", "\"abc\"", "module_name", Range::default()),
-                Lint::new("incorrect_match", "group1", "\"abc\"", "module_name", Range::default()),
-            ],
-        );
-        expected.insert(
-            "group2".to_string(),
-            vec![Lint::new(
-                "should_assert_eq2",
-                "group2",
-                "\"abc\"",
-                "module_name",
-                Range::default(),
-            )],
-        );
-        assert_eq!(expected, Lint::by_lint_group(lints.into_iter()));
-    }
 }