more cascady

## Summary

I wondered if this might improve performance a little. It doesn't seem
to, but it's a net reduction in LOC and I think the changes make sense.
I think it's worth it anyway just in terms of simplifying the code.

## Test Plan

Our existing tests all pass and the primer report is clean (aside from
our usual flakes).

.github/CODEOWNERS

@@ -20,9 +20,11 @@
 # ty
 /crates/ty* @carljm @MichaReiser @AlexWaygood @sharkdp @dcreager
 /crates/ruff_db/ @carljm @MichaReiser @sharkdp @dcreager
-/crates/ty_project/ @carljm @MichaReiser @sharkdp @dcreager
-/crates/ty_server/ @carljm @MichaReiser @sharkdp @dcreager
+/crates/ty_project/ @carljm @MichaReiser @sharkdp @dcreager @Gankra
+/crates/ty_ide/ @carljm @MichaReiser @AlexWaygood @sharkdp @dcreager @Gankra
+/crates/ty_server/ @carljm @MichaReiser @sharkdp @dcreager @Gankra
 /crates/ty/ @carljm @MichaReiser @sharkdp @dcreager
-/crates/ty_wasm/ @carljm @MichaReiser @sharkdp @dcreager
+/crates/ty_wasm/ @carljm @MichaReiser @sharkdp @dcreager @Gankra
 /scripts/ty_benchmark/ @carljm @MichaReiser @AlexWaygood @sharkdp @dcreager
-/crates/ty_python_semantic @carljm @AlexWaygood @sharkdp @dcreager
+/crates/ty_python_semantic/ @carljm @AlexWaygood @sharkdp @dcreager
+/crates/ty_module_resolver/ @carljm @MichaReiser @AlexWaygood @Gankra

CLAUDE.md

@@ -10,6 +10,12 @@ Run all tests (using `nextest` for faster execution):
 cargo nextest run
 ```
 
+For faster test execution, use the `fast-test` profile which enables optimizations while retaining debug info:
+
+```sh
+cargo nextest run --cargo-profile fast-test
+```
+
 Run tests for a specific crate:
 
 ```sh

Cargo.lock

@@ -4511,11 +4511,13 @@ dependencies = [
  "regex-automata",
  "ruff_cache",
  "ruff_db",
+ "ruff_diagnostics",
  "ruff_macros",
  "ruff_memory_usage",
  "ruff_options_metadata",
  "ruff_python_ast",
  "ruff_python_formatter",
+ "ruff_python_trivia",
  "ruff_text_size",
  "rustc-hash",
  "salsa",

Cargo.toml

@@ -335,6 +335,11 @@ strip = false
 debug = "full"
 lto = false
 
+# Profile for faster iteration: applies minimal optimizations for faster tests.
+[profile.fast-test]
+inherits = "dev"
+opt-level = 1
+
 # The profile that 'cargo dist' will build with.
 [profile.dist]
 inherits = "release"

crates/ruff_benchmark/benches/ty.rs

@@ -221,7 +221,7 @@ fn setup_micro_case(code: &str) -> Case {
     let file_path = "src/test.py";
     fs.write_file_all(
         SystemPathBuf::from(file_path),
-        ruff_python_trivia::textwrap::dedent(code),
+        &*ruff_python_trivia::textwrap::dedent(code),
     )
     .unwrap();
 

crates/ruff_db/src/cancellation.rs

@@ -1,3 +1,4 @@
+use std::fmt::Formatter;
 use std::sync::Arc;
 use std::sync::atomic::AtomicBool;
 
@@ -49,3 +50,15 @@ impl CancellationToken {
         self.cancelled.load(std::sync::atomic::Ordering::Relaxed)
     }
 }
+
+/// The operation was canceled by the provided [`CancellationToken`].
+#[derive(Debug)]
+pub struct Canceled;
+
+impl std::error::Error for Canceled {}
+
+impl std::fmt::Display for Canceled {
+    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+        f.write_str("operation was canceled")
+    }
+}

crates/ruff_db/src/diagnostic/mod.rs

@@ -98,6 +98,44 @@ impl Diagnostic {
         diag
     }
 
+    /// Adds sub diagnostics that tell the user that this is a bug in ty
+    /// and asks them to open an issue on GitHub.
+    pub fn add_bug_sub_diagnostics(&mut self, url_encoded_title: &str) {
+        self.sub(SubDiagnostic::new(
+            SubDiagnosticSeverity::Info,
+            "This indicates a bug in ty.",
+        ));
+
+        self.sub(SubDiagnostic::new(
+            SubDiagnosticSeverity::Info,
+            format_args!(
+                "If you could open an issue at https://github.com/astral-sh/ty/issues/new?title={url_encoded_title}, we'd be very appreciative!"
+            ),
+        ));
+        self.sub(SubDiagnostic::new(
+            SubDiagnosticSeverity::Info,
+            format!(
+                "Platform: {os} {arch}",
+                os = std::env::consts::OS,
+                arch = std::env::consts::ARCH
+            ),
+        ));
+        if let Some(version) = crate::program_version() {
+            self.sub(SubDiagnostic::new(
+                SubDiagnosticSeverity::Info,
+                format!("Version: {version}"),
+            ));
+        }
+
+        self.sub(SubDiagnostic::new(
+            SubDiagnosticSeverity::Info,
+            format!(
+                "Args: {args:?}",
+                args = std::env::args().collect::<Vec<_>>()
+            ),
+        ));
+    }
+
     /// Add an annotation to this diagnostic.
     ///
     /// Annotations for a diagnostic are optional, but if any are added,
@@ -1019,6 +1057,13 @@ impl DiagnosticId {
         matches!(self, DiagnosticId::Lint(_))
     }
 
+    pub const fn as_lint(&self) -> Option<LintName> {
+        match self {
+            DiagnosticId::Lint(name) => Some(*name),
+            _ => None,
+        }
+    }
+
     /// Returns `true` if this `DiagnosticId` represents a lint with the given name.
     pub fn is_lint_named(&self, name: &str) -> bool {
         matches!(self, DiagnosticId::Lint(self_name) if self_name == name)

crates/ruff_db/src/files.rs

@@ -14,6 +14,7 @@ use crate::diagnostic::{Span, UnifiedFile};
 use crate::file_revision::FileRevision;
 use crate::files::file_root::FileRoots;
 use crate::files::private::FileStatus;
+use crate::source::SourceText;
 use crate::system::{SystemPath, SystemPathBuf, SystemVirtualPath, SystemVirtualPathBuf};
 use crate::vendored::{VendoredPath, VendoredPathBuf};
 use crate::{Db, FxDashMap, vendored};
@@ -323,6 +324,17 @@ pub struct File {
     /// the file has been deleted is to change the status to `Deleted`.
     #[default]
     status: FileStatus,
+
+    /// Overrides the result of [`source_text`](crate::source::source_text).
+    ///
+    /// This is useful when running queries after modifying a file's content but
+    /// before the content is written to disk. For example, to verify that the applied fixes
+    /// didn't introduce any new errors.
+    ///
+    /// The override gets automatically removed the next time the file changes.
+    #[default]
+    #[returns(ref)]
+    pub source_text_override: Option<SourceText>,
 }
 
 // The Salsa heap is tracked separately.
@@ -444,20 +456,28 @@ impl File {
             _ => (FileStatus::NotFound, FileRevision::zero(), None),
         };
 
+        let mut clear_override = false;
+
         if file.status(db) != status {
             tracing::debug!("Updating the status of `{}`", file.path(db));
             file.set_status(db).to(status);
+            clear_override = true;
         }
 
         if file.revision(db) != revision {
             tracing::debug!("Updating the revision of `{}`", file.path(db));
             file.set_revision(db).to(revision);
+            clear_override = true;
         }
 
         if file.permissions(db) != permission {
             tracing::debug!("Updating the permissions of `{}`", file.path(db));
             file.set_permissions(db).to(permission);
         }
+
+        if clear_override && file.source_text_override(db).is_some() {
+            file.set_source_text_override(db).to(None);
+        }
     }
 
     /// Returns `true` if the file exists.
@@ -526,7 +546,7 @@ impl VirtualFile {
     }
 
     /// Increments the revision of the underlying [`File`].
-    fn sync(&self, db: &mut dyn Db) {
+    pub fn sync(&self, db: &mut dyn Db) {
         let file = self.0;
         tracing::debug!("Updating the revision of `{}`", file.path(db));
         let current_revision = file.revision(db);

crates/ruff_db/src/lib.rs

@@ -85,6 +85,13 @@ pub fn max_parallelism() -> NonZeroUsize {
         })
 }
 
+// Use a reasonably large stack size to avoid running into stack overflows too easily. The
+// size was chosen in such a way as to still be able to handle large expressions involving
+// binary operators (x + x + … + x) both during the AST walk in semantic index building as
+// well as during type checking. Using this stack size, we can handle handle expressions
+// that are several times larger than the corresponding limits in existing type checkers.
+pub const STACK_SIZE: usize = 16 * 1024 * 1024;
+
 /// Trait for types that can provide Rust documentation.
 ///
 /// Use `derive(RustDoc)` to automatically implement this trait for types that have a static string documentation.

crates/ruff_db/src/source.rs

@@ -1,6 +1,8 @@
+use std::borrow::Cow;
 use std::ops::Deref;
 use std::sync::Arc;
 
+use ruff_diagnostics::SourceMap;
 use ruff_notebook::Notebook;
 use ruff_python_ast::PySourceType;
 use ruff_source_file::LineIndex;
@@ -16,6 +18,10 @@ pub fn source_text(db: &dyn Db, file: File) -> SourceText {
     let _span = tracing::trace_span!("source_text", file = %path).entered();
     let mut read_error = None;
 
+    if let Some(source) = file.source_text_override(db) {
+        return source.clone();
+    }
+
     let kind = if is_notebook(db.system(), path) {
         file.read_to_notebook(db)
             .unwrap_or_else(|error| {
@@ -90,6 +96,45 @@ impl SourceText {
     pub fn read_error(&self) -> Option<&SourceTextError> {
         self.inner.read_error.as_ref()
     }
+
+    /// Returns a new instance for this file with the updated source text (Python code).
+    ///
+    /// Uses the `source_map` to preserve the cell-boundaries.
+    #[must_use]
+    pub fn with_text(&self, new_text: String, source_map: &SourceMap) -> Self {
+        let new_kind = match &self.inner.kind {
+            SourceTextKind::Text(_) => SourceTextKind::Text(new_text),
+
+            SourceTextKind::Notebook { notebook } => {
+                let mut new_notebook = notebook.as_ref().clone();
+                new_notebook.update(source_map, new_text);
+                SourceTextKind::Notebook {
+                    notebook: new_notebook.into(),
+                }
+            }
+        };
+
+        Self {
+            inner: Arc::new(SourceTextInner {
+                kind: new_kind,
+                read_error: self.inner.read_error.clone(),
+            }),
+        }
+    }
+
+    pub fn to_bytes(&self) -> Cow<'_, [u8]> {
+        match &self.inner.kind {
+            SourceTextKind::Text(source) => Cow::Borrowed(source.as_bytes()),
+            SourceTextKind::Notebook { notebook } => {
+                let mut output: Vec<u8> = Vec::new();
+                notebook
+                    .write(&mut output)
+                    .expect("writing to a Vec should never fail");
+
+                Cow::Owned(output)
+            }
+        }
+    }
 }
 
 impl Deref for SourceText {
@@ -117,13 +162,13 @@ impl std::fmt::Debug for SourceText {
     }
 }
 
-#[derive(Eq, PartialEq, get_size2::GetSize)]
+#[derive(Eq, PartialEq, get_size2::GetSize, Clone)]
 struct SourceTextInner {
     kind: SourceTextKind,
     read_error: Option<SourceTextError>,
 }
 
-#[derive(Eq, PartialEq, get_size2::GetSize)]
+#[derive(Eq, PartialEq, get_size2::GetSize, Clone)]
 enum SourceTextKind {
     Text(String),
     Notebook {

crates/ruff_db/src/system.rs

@@ -271,7 +271,12 @@ pub trait WritableSystem: System {
     fn create_new_file(&self, path: &SystemPath) -> Result<()>;
 
     /// Writes the given content to the file at the given path.
-    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()>;
+    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()> {
+        self.write_file_bytes(path, content.as_bytes())
+    }
+
+    /// Writes the given content to the file at the given path.
+    fn write_file_bytes(&self, path: &SystemPath, content: &[u8]) -> Result<()>;
 
     /// Creates a directory at `path` as well as any intermediate directories.
     fn create_directory_all(&self, path: &SystemPath) -> Result<()>;
@@ -311,6 +316,8 @@ pub trait WritableSystem: System {
 
         Ok(Some(cache_path))
     }
+
+    fn dyn_clone(&self) -> Box<dyn WritableSystem>;
 }
 
 #[derive(Clone, Debug, Eq, PartialEq)]

crates/ruff_db/src/system/memory_fs.rs

@@ -122,7 +122,9 @@ impl MemoryFileSystem {
             let entry = by_path.get(&normalized).ok_or_else(not_found)?;
 
             match entry {
-                Entry::File(file) => Ok(file.content.clone()),
+                Entry::File(file) => {
+                    String::from_utf8(file.content.to_vec()).map_err(|_| invalid_utf8())
+                }
                 Entry::Directory(_) => Err(is_a_directory()),
             }
         }
@@ -139,7 +141,7 @@ impl MemoryFileSystem {
             .get(&path.as_ref().to_path_buf())
             .ok_or_else(not_found)?;
 
-        Ok(file.content.clone())
+        String::from_utf8(file.content.to_vec()).map_err(|_| invalid_utf8())
     }
 
     pub fn exists(&self, path: &SystemPath) -> bool {
@@ -161,7 +163,7 @@ impl MemoryFileSystem {
         match by_path.entry(normalized) {
             btree_map::Entry::Vacant(entry) => {
                 entry.insert(Entry::File(File {
-                    content: String::new(),
+                    content: Box::default(),
                     last_modified: file_time_now(),
                 }));
 
@@ -177,13 +179,17 @@ impl MemoryFileSystem {
     /// Stores a new file in the file system.
     ///
     /// The operation overrides the content for an existing file with the same normalized `path`.
-    pub fn write_file(&self, path: impl AsRef<SystemPath>, content: impl ToString) -> Result<()> {
+    pub fn write_file(
+        &self,
+        path: impl AsRef<SystemPath>,
+        content: impl AsRef<[u8]>,
+    ) -> Result<()> {
         let mut by_path = self.inner.by_path.write().unwrap();
 
         let normalized = self.normalize_path(path.as_ref());
 
         let file = get_or_create_file(&mut by_path, &normalized)?;
-        file.content = content.to_string();
+        file.content = content.as_ref().to_vec().into_boxed_slice();
         file.last_modified = file_time_now();
 
         Ok(())
@@ -214,7 +220,7 @@ impl MemoryFileSystem {
     pub fn write_file_all(
         &self,
         path: impl AsRef<SystemPath>,
-        content: impl ToString,
+        content: impl AsRef<[u8]>,
     ) -> Result<()> {
         let path = path.as_ref();
 
@@ -228,19 +234,24 @@ impl MemoryFileSystem {
     /// Stores a new virtual file in the file system.
     ///
     /// The operation overrides the content for an existing virtual file with the same `path`.
-    pub fn write_virtual_file(&self, path: impl AsRef<SystemVirtualPath>, content: impl ToString) {
+    pub fn write_virtual_file(
+        &self,
+        path: impl AsRef<SystemVirtualPath>,
+        content: impl AsRef<[u8]>,
+    ) {
         let path = path.as_ref();
         let mut virtual_files = self.inner.virtual_files.write().unwrap();
+        let content = content.as_ref().to_vec().into_boxed_slice();
 
         match virtual_files.entry(path.to_path_buf()) {
             std::collections::hash_map::Entry::Vacant(entry) => {
                 entry.insert(File {
-                    content: content.to_string(),
+                    content,
                     last_modified: file_time_now(),
                 });
             }
             std::collections::hash_map::Entry::Occupied(mut entry) => {
-                entry.get_mut().content = content.to_string();
+                entry.get_mut().content = content;
             }
         }
     }
@@ -468,7 +479,7 @@ impl Entry {
 
 #[derive(Debug)]
 struct File {
-    content: String,
+    content: Box<[u8]>,
     last_modified: FileTime,
 }
 
@@ -497,6 +508,13 @@ fn directory_not_empty() -> std::io::Error {
     std::io::Error::other("directory not empty")
 }
 
+fn invalid_utf8() -> std::io::Error {
+    std::io::Error::new(
+        std::io::ErrorKind::InvalidData,
+        "stream did not contain valid UTF-8",
+    )
+}
+
 fn create_dir_all(
     paths: &mut RwLockWriteGuard<BTreeMap<Utf8PathBuf, Entry>>,
     normalized: &Utf8Path,
@@ -533,7 +551,7 @@ fn get_or_create_file<'a>(
 
     let entry = paths.entry(normalized.to_path_buf()).or_insert_with(|| {
         Entry::File(File {
-            content: String::new(),
+            content: Box::default(),
             last_modified: file_time_now(),
         })
     });
@@ -844,7 +862,7 @@ mod tests {
         let fs = with_files(["c.py"]);
 
         let error = fs
-            .write_file(SystemPath::new("a/b.py"), "content".to_string())
+            .write_file(SystemPath::new("a/b.py"), "content")
             .unwrap_err();
 
         assert_eq!(error.kind(), ErrorKind::NotFound);
@@ -855,7 +873,7 @@ mod tests {
         let fs = with_files(["a/b.py"]);
 
         let error = fs
-            .write_file_all(SystemPath::new("a/b.py/c"), "content".to_string())
+            .write_file_all(SystemPath::new("a/b.py/c"), "content")
             .unwrap_err();
 
         assert_eq!(error.kind(), ErrorKind::Other);
@@ -878,7 +896,7 @@ mod tests {
         let fs = MemoryFileSystem::new();
         let path = SystemPath::new("a.py");
 
-        fs.write_file_all(path, "Test content".to_string())?;
+        fs.write_file_all(path, "Test content")?;
 
         assert_eq!(fs.read_to_string(path)?, "Test content");
 
@@ -915,9 +933,7 @@ mod tests {
 
         fs.create_directory_all("a")?;
 
-        let error = fs
-            .write_file(SystemPath::new("a"), "content".to_string())
-            .unwrap_err();
+        let error = fs.write_file(SystemPath::new("a"), "content").unwrap_err();
 
         assert_eq!(error.kind(), ErrorKind::Other);
 

crates/ruff_db/src/system/os.rs

@@ -361,13 +361,17 @@ impl WritableSystem for OsSystem {
         std::fs::File::create_new(path).map(drop)
     }
 
-    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()> {
+    fn write_file_bytes(&self, path: &SystemPath, content: &[u8]) -> Result<()> {
         std::fs::write(path.as_std_path(), content)
     }
 
     fn create_directory_all(&self, path: &SystemPath) -> Result<()> {
         std::fs::create_dir_all(path.as_std_path())
     }
+
+    fn dyn_clone(&self) -> Box<dyn WritableSystem> {
+        Box::new(self.clone())
+    }
 }
 
 impl Default for OsSystem {

crates/ruff_db/src/system/test.rs

@@ -205,13 +205,17 @@ impl WritableSystem for TestSystem {
         self.system().create_new_file(path)
     }
 
-    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()> {
-        self.system().write_file(path, content)
+    fn write_file_bytes(&self, path: &SystemPath, content: &[u8]) -> Result<()> {
+        self.system().write_file_bytes(path, content)
     }
 
     fn create_directory_all(&self, path: &SystemPath) -> Result<()> {
         self.system().create_directory_all(path)
     }
+
+    fn dyn_clone(&self) -> Box<dyn WritableSystem> {
+        Box::new(self.clone())
+    }
 }
 
 /// Extension trait for databases that use a [`WritableSystem`].
@@ -283,7 +287,11 @@ pub trait DbWithTestSystem: Db + Sized {
     ///
     /// ## Panics
     /// If the db isn't using the [`InMemorySystem`].
-    fn write_virtual_file(&mut self, path: impl AsRef<SystemVirtualPath>, content: impl ToString) {
+    fn write_virtual_file(
+        &mut self,
+        path: impl AsRef<SystemVirtualPath>,
+        content: impl AsRef<[u8]>,
+    ) {
         let path = path.as_ref();
         self.test_system()
             .memory_file_system()
@@ -322,23 +330,23 @@ where
     }
 }
 
-#[derive(Default, Debug)]
+#[derive(Clone, Default, Debug)]
 pub struct InMemorySystem {
-    user_config_directory: Mutex<Option<SystemPathBuf>>,
+    user_config_directory: Arc<Mutex<Option<SystemPathBuf>>>,
     memory_fs: MemoryFileSystem,
 }
 
 impl InMemorySystem {
     pub fn new(cwd: SystemPathBuf) -> Self {
         Self {
-            user_config_directory: Mutex::new(None),
+            user_config_directory: Mutex::new(None).into(),
             memory_fs: MemoryFileSystem::with_current_directory(cwd),
         }
     }
 
     pub fn from_memory_fs(memory_fs: MemoryFileSystem) -> Self {
         Self {
-            user_config_directory: Mutex::new(None),
+            user_config_directory: Mutex::new(None).into(),
             memory_fs,
         }
     }
@@ -440,10 +448,7 @@ impl System for InMemorySystem {
     }
 
     fn dyn_clone(&self) -> Box<dyn System> {
-        Box::new(Self {
-            user_config_directory: Mutex::new(self.user_config_directory.lock().unwrap().clone()),
-            memory_fs: self.memory_fs.clone(),
-        })
+        Box::new(self.clone())
     }
 }
 
@@ -452,11 +457,15 @@ impl WritableSystem for InMemorySystem {
         self.memory_fs.create_new_file(path)
     }
 
-    fn write_file(&self, path: &SystemPath, content: &str) -> Result<()> {
+    fn write_file_bytes(&self, path: &SystemPath, content: &[u8]) -> Result<()> {
         self.memory_fs.write_file(path, content)
     }
 
     fn create_directory_all(&self, path: &SystemPath) -> Result<()> {
         self.memory_fs.create_directory_all(path)
     }
+
+    fn dyn_clone(&self) -> Box<dyn WritableSystem> {
+        Box::new(self.clone())
+    }
 }

crates/ruff_linter/src/linter.rs

@@ -26,6 +26,7 @@ use crate::doc_lines::{doc_lines_from_ast, doc_lines_from_tokens};
 use crate::fix::{FixResult, fix_file};
 use crate::noqa::add_noqa;
 use crate::package::PackageRoot;
+use crate::preview::is_py315_support_enabled;
 use crate::registry::Rule;
 #[cfg(any(feature = "test-rules", test))]
 use crate::rules::ruff::rules::test_rules::{self, TEST_RULES, TestRule};
@@ -33,7 +34,7 @@ use crate::settings::types::UnsafeFixes;
 use crate::settings::{LinterSettings, TargetVersion, flags};
 use crate::source_kind::SourceKind;
 use crate::suppression::Suppressions;
-use crate::{Locator, directives, fs};
+use crate::{Locator, directives, fs, warn_user_once};
 
 pub(crate) mod float;
 
@@ -450,6 +451,14 @@ pub fn lint_only(
 ) -> LinterResult {
     let target_version = settings.resolve_target_version(path);
 
+    if matches!(target_version.linter_version(), PythonVersion::PY315)
+        && !is_py315_support_enabled(settings)
+    {
+        warn_user_once!(
+            "Support for Python 3.15 is under development and may be unstable. Enable `preview` to remove this warning."
+        );
+    }
+
     let parsed = source.into_parsed(source_kind, source_type, target_version.parser_version());
 
     // Map row and column locations to byte slices (lazily).
@@ -555,6 +564,14 @@ pub fn lint_fix<'a>(
 
     let target_version = settings.resolve_target_version(path);
 
+    if matches!(target_version.linter_version(), PythonVersion::PY315)
+        && !is_py315_support_enabled(settings)
+    {
+        warn_user_once!(
+            "Support for Python 3.15 is under development and may be unstable. Enable `preview` to remove this warning."
+        );
+    }
+
     // Continuously fix until the source code stabilizes.
     loop {
         // Parse once.

crates/ruff_linter/src/preview.rs

@@ -296,3 +296,8 @@ pub(crate) const fn is_s310_resolve_string_literal_bindings_enabled(
 pub(crate) const fn is_range_suppressions_enabled(settings: &LinterSettings) -> bool {
     settings.preview.is_enabled()
 }
+
+// https://github.com/astral-sh/ruff/pull/22419
+pub(crate) const fn is_py315_support_enabled(settings: &LinterSettings) -> bool {
+    settings.preview.is_enabled()
+}

crates/ruff_linter/src/rules/flake8_print/rules/print_call.rs

@@ -36,13 +36,16 @@ use crate::{Fix, FixAvailability, Violation};
 /// ```python
 /// import logging
 ///
-/// logging.basicConfig(level=logging.INFO)
 /// logger = logging.getLogger(__name__)
 ///
 ///
 /// def sum_less_than_four(a, b):
 ///     logger.debug("Calling sum_less_than_four")
 ///     return a + b < 4
+///
+///
+/// if __name__ == "__main__":
+///     logging.basicConfig(level=logging.INFO)
 /// ```
 ///
 /// ## Fix safety

crates/ruff_linter/src/rules/pylint/rules/subprocess_run_without_check.rs

@@ -5,7 +5,7 @@ use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
 use crate::fix::edits::add_argument;
-use crate::{AlwaysFixableViolation, Applicability, Fix};
+use crate::{Fix, FixAvailability, Violation};
 
 /// ## What it does
 /// Checks for uses of `subprocess.run` without an explicit `check` argument.
@@ -39,9 +39,12 @@ use crate::{AlwaysFixableViolation, Applicability, Fix};
 /// ```
 ///
 /// ## Fix safety
-/// This rule's fix is marked as unsafe for function calls that contain
-/// `**kwargs`, as adding a `check` keyword argument to such a call may lead
-/// to a duplicate keyword argument error.
+///
+/// This rule's fix is marked as display-only because it's not clear whether the
+/// potential exception was meant to be ignored by setting `check=False` or if
+/// the author simply forgot to include `check=True`. The fix adds
+/// `check=False`, making the existing behavior explicit but possibly masking
+/// the original intention.
 ///
 /// ## References
 /// - [Python documentation: `subprocess.run`](https://docs.python.org/3/library/subprocess.html#subprocess.run)
@@ -49,14 +52,18 @@ use crate::{AlwaysFixableViolation, Applicability, Fix};
 #[violation_metadata(stable_since = "v0.0.285")]
 pub(crate) struct SubprocessRunWithoutCheck;
 
-impl AlwaysFixableViolation for SubprocessRunWithoutCheck {
+impl Violation for SubprocessRunWithoutCheck {
+    // The fix is always set on the diagnostic, but display-only fixes aren't
+    // considered "fixable" in the tests.
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::Sometimes;
+
     #[derive_message_formats]
     fn message(&self) -> String {
         "`subprocess.run` without explicit `check` argument".to_string()
     }
 
-    fn fix_title(&self) -> String {
-        "Add explicit `check=False`".to_string()
+    fn fix_title(&self) -> Option<String> {
+        Some("Add explicit `check=False`".to_string())
     }
 }
 
@@ -74,20 +81,11 @@ pub(crate) fn subprocess_run_without_check(checker: &Checker, call: &ast::ExprCa
         if call.arguments.find_keyword("check").is_none() {
             let mut diagnostic =
                 checker.report_diagnostic(SubprocessRunWithoutCheck, call.func.range());
-            diagnostic.set_fix(Fix::applicable_edit(
-                add_argument("check=False", &call.arguments, checker.tokens()),
-                // If the function call contains `**kwargs`, mark the fix as unsafe.
-                if call
-                    .arguments
-                    .keywords
-                    .iter()
-                    .any(|keyword| keyword.arg.is_none())
-                {
-                    Applicability::Unsafe
-                } else {
-                    Applicability::Safe
-                },
-            ));
+            diagnostic.set_fix(Fix::display_only_edit(add_argument(
+                "check=False",
+                &call.arguments,
+                checker.tokens(),
+            )));
         }
     }
 }

crates/ruff_linter/src/rules/pylint/snapshots/ruff_linter__rules__pylint__tests__PLW1510_subprocess_run_without_check.py.snap

@@ -19,6 +19,7 @@ help: Add explicit `check=False`
 5 | subprocess.run("ls", shell=True)
 6 | subprocess.run(
 7 |     ["ls"],
+note: This is a display-only fix and is likely to be incorrect
 
 PLW1510 [*] `subprocess.run` without explicit `check` argument
  --> subprocess_run_without_check.py:5:1
@@ -39,6 +40,7 @@ help: Add explicit `check=False`
 6 | subprocess.run(
 7 |     ["ls"],
 8 |     shell=False,
+note: This is a display-only fix and is likely to be incorrect
 
 PLW1510 [*] `subprocess.run` without explicit `check` argument
  --> subprocess_run_without_check.py:6:1
@@ -59,6 +61,7 @@ help: Add explicit `check=False`
 9  | )
 10 | subprocess.run(["ls"], **kwargs)
 11 | 
+note: This is a display-only fix and is likely to be incorrect
 
 PLW1510 [*] `subprocess.run` without explicit `check` argument
   --> subprocess_run_without_check.py:10:1
@@ -79,4 +82,4 @@ help: Add explicit `check=False`
 11 | 
 12 | # Non-errors.
 13 | subprocess.run("ls", check=True)
-note: This is an unsafe fix and may change runtime behavior
+note: This is a display-only fix and is likely to be incorrect

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__range_suppressions.snap

@@ -7,7 +7,7 @@ source: crates/ruff_linter/src/rules/ruff/mod.rs
 
 --- Summary ---
 Removed: 15
-Added: 23
+Added: 20
 
 --- Removed ---
 E741 Ambiguous variable name: `I`
@@ -301,6 +301,7 @@ RUF100 [*] Unused suppression (non-enabled: `E501`)
    |     ^^^^^^^^^^^^^^^^^^^^^
 47 |     I = 1
 48 |     # ruff: enable[E501]
+   |     --------------------
    |
 help: Remove unused suppression
 43 | def f():
@@ -308,26 +309,10 @@ help: Remove unused suppression
 45 |     # logged to user
    -     # ruff: disable[E501]
 46 |     I = 1
-47 |     # ruff: enable[E501]
-48 | 
-
-
-RUF100 [*] Unused suppression (non-enabled: `E501`)
-  --> suppressions.py:48:5
-   |
-46 |     # ruff: disable[E501]
-47 |     I = 1
-48 |     # ruff: enable[E501]
-   |     ^^^^^^^^^^^^^^^^^^^^
-   |
-help: Remove unused suppression
-45 |     # logged to user
-46 |     # ruff: disable[E501]
-47 |     I = 1
    -     # ruff: enable[E501]
+47 | 
 48 | 
-49 | 
-50 | def f():
+49 | def f():
 
 
 RUF100 [*] Unused `noqa` directive (unused: `E741`, `F841`)
@@ -563,6 +548,9 @@ RUF102 [*] Invalid rule code in suppression: YF829
    |                     ^^^^^
 94 |     # ruff: disable[F841, RQW320]
 95 |     value = 0
+96 |     # ruff: enable[F841, RQW320]
+97 |     # ruff: enable[YF829]
+   |                    -----
    |
 help: Remove the rule code
 90 | 
@@ -572,6 +560,10 @@ help: Remove the rule code
 93 |     # ruff: disable[F841, RQW320]
 94 |     value = 0
 95 |     # ruff: enable[F841, RQW320]
+   -     # ruff: enable[YF829]
+96 | 
+97 | 
+98 | def f():
 
 
 RUF102 [*] Invalid rule code in suppression: RQW320
@@ -583,6 +575,8 @@ RUF102 [*] Invalid rule code in suppression: RQW320
    |                           ^^^^^^
 95 |     value = 0
 96 |     # ruff: enable[F841, RQW320]
+   |                          ------
+97 |     # ruff: enable[YF829]
    |
 help: Remove the rule code
 91 | def f():
@@ -590,23 +584,6 @@ help: Remove the rule code
 93 |     # ruff: disable[YF829]
    -     # ruff: disable[F841, RQW320]
 94 +     # ruff: disable[F841]
-95 |     value = 0
-96 |     # ruff: enable[F841, RQW320]
-97 |     # ruff: enable[YF829]
-
-
-RUF102 [*] Invalid rule code in suppression: RQW320
-  --> suppressions.py:96:26
-   |
-94 |     # ruff: disable[F841, RQW320]
-95 |     value = 0
-96 |     # ruff: enable[F841, RQW320]
-   |                          ^^^^^^
-97 |     # ruff: enable[YF829]
-   |
-help: Remove the rule code
-93 |     # ruff: disable[YF829]
-94 |     # ruff: disable[F841, RQW320]
 95 |     value = 0
    -     # ruff: enable[F841, RQW320]
 96 +     # ruff: enable[F841]
@@ -615,24 +592,6 @@ help: Remove the rule code
 99 | 
 
 
-RUF102 [*] Invalid rule code in suppression: YF829
-  --> suppressions.py:97:20
-   |
-95 |     value = 0
-96 |     # ruff: enable[F841, RQW320]
-97 |     # ruff: enable[YF829]
-   |                    ^^^^^
-   |
-help: Remove the rule code
-94 |     # ruff: disable[F841, RQW320]
-95 |     value = 0
-96 |     # ruff: enable[F841, RQW320]
-   -     # ruff: enable[YF829]
-97 | 
-98 | 
-99 | def f():
-
-
 RUF103 [*] Invalid suppression comment: missing suppression codes like `[E501, ...]`
    --> suppressions.py:109:5
     |

crates/ruff_linter/src/settings/types.rs

@@ -36,6 +36,7 @@ pub enum PythonVersion {
     Py312,
     Py313,
     Py314,
+    Py315,
 }
 
 impl Default for PythonVersion {
@@ -58,6 +59,7 @@ impl TryFrom<ast::PythonVersion> for PythonVersion {
             ast::PythonVersion::PY312 => Ok(Self::Py312),
             ast::PythonVersion::PY313 => Ok(Self::Py313),
             ast::PythonVersion::PY314 => Ok(Self::Py314),
+            ast::PythonVersion::PY315 => Ok(Self::Py315),
             _ => Err(format!("unrecognized python version {value}")),
         }
     }
@@ -88,6 +90,7 @@ impl PythonVersion {
             Self::Py312 => (3, 12),
             Self::Py313 => (3, 13),
             Self::Py314 => (3, 14),
+            Self::Py315 => (3, 15),
         }
     }
 }

crates/ruff_linter/src/suppression.rs

@@ -13,7 +13,6 @@ use ruff_python_trivia::Cursor;
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize, TextSlice};
 use smallvec::{SmallVec, smallvec};
 
-use crate::Locator;
 use crate::checkers::ast::LintContext;
 use crate::codes::Rule;
 use crate::fix::edits::delete_comment;
@@ -24,6 +23,7 @@ use crate::rules::ruff::rules::{
     UnmatchedSuppressionComment, UnusedCodes, UnusedNOQA, UnusedNOQAKind, code_is_valid,
 };
 use crate::settings::LinterSettings;
+use crate::{Locator, Violation};
 
 #[derive(Clone, Debug, Eq, PartialEq)]
 enum SuppressionAction {
@@ -85,11 +85,33 @@ pub(crate) struct Suppression {
     /// Range for which the suppression applies
     range: TextRange,
 
-    /// Any comments associated with the suppression
-    comments: SmallVec<[SuppressionComment; 2]>,
-
     /// Whether this suppression actually suppressed a diagnostic
     used: Cell<bool>,
+
+    comments: DisableEnableComments,
+}
+
+#[derive(Debug)]
+pub(crate) enum DisableEnableComments {
+    /// An implicitly closed disable comment without a matching enable comment.
+    Disable(SuppressionComment),
+    /// A matching pair of disable and enable comments.
+    DisableEnable(SuppressionComment, SuppressionComment),
+}
+
+impl DisableEnableComments {
+    pub(crate) fn disable_comment(&self) -> &SuppressionComment {
+        match self {
+            DisableEnableComments::Disable(comment) => comment,
+            DisableEnableComments::DisableEnable(disable, _) => disable,
+        }
+    }
+    pub(crate) fn enable_comment(&self) -> Option<&SuppressionComment> {
+        match self {
+            DisableEnableComments::Disable(_) => None,
+            DisableEnableComments::DisableEnable(_, enable) => Some(enable),
+        }
+    }
 }
 
 #[derive(Copy, Clone, Debug)]
@@ -171,23 +193,16 @@ impl Suppressions {
             if !code_is_valid(&suppression.code, &context.settings().external) {
                 // InvalidRuleCode
                 if context.is_rule_enabled(Rule::InvalidRuleCode) {
-                    for comment in &suppression.comments {
-                        let (range, edit) = Suppressions::delete_code_or_comment(
-                            locator,
-                            suppression,
-                            comment,
-                            true,
-                        );
-                        context
-                            .report_diagnostic(
-                                InvalidRuleCode {
-                                    rule_code: suppression.code.to_string(),
-                                    kind: InvalidRuleCodeKind::Suppression,
-                                },
-                                range,
-                            )
-                            .set_fix(Fix::safe_edit(edit));
-                    }
+                    Suppressions::report_suppression(
+                        context,
+                        locator,
+                        suppression,
+                        true,
+                        InvalidRuleCode {
+                            rule_code: suppression.code.to_string(),
+                            kind: InvalidRuleCodeKind::Suppression,
+                        },
+                    );
                 }
             } else if !suppression.used.get() {
                 // UnusedNOQA
@@ -197,42 +212,37 @@ impl Suppressions {
                     ) else {
                         continue; // "external" lint code, don't treat it as unused
                     };
-                    for comment in &suppression.comments {
-                        let (range, edit) = Suppressions::delete_code_or_comment(
-                            locator,
-                            suppression,
-                            comment,
-                            false,
-                        );
 
-                        let codes = if context.is_rule_enabled(rule) {
-                            UnusedCodes {
-                                unmatched: vec![suppression.code.to_string()],
-                                ..Default::default()
-                            }
-                        } else {
-                            UnusedCodes {
-                                disabled: vec![suppression.code.to_string()],
-                                ..Default::default()
-                            }
-                        };
+                    let codes = if context.is_rule_enabled(rule) {
+                        UnusedCodes {
+                            unmatched: vec![suppression.code.to_string()],
+                            ..Default::default()
+                        }
+                    } else {
+                        UnusedCodes {
+                            disabled: vec![suppression.code.to_string()],
+                            ..Default::default()
+                        }
+                    };
 
-                        context
-                            .report_diagnostic(
-                                UnusedNOQA {
-                                    codes: Some(codes),
-                                    kind: UnusedNOQAKind::Suppression,
-                                },
-                                range,
-                            )
-                            .set_fix(Fix::safe_edit(edit));
-                    }
+                    Suppressions::report_suppression(
+                        context,
+                        locator,
+                        suppression,
+                        false,
+                        UnusedNOQA {
+                            codes: Some(codes),
+                            kind: UnusedNOQAKind::Suppression,
+                        },
+                    );
                 }
-            } else if suppression.comments.len() == 1 {
+            } else if let DisableEnableComments::Disable(comment) = &suppression.comments {
                 // UnmatchedSuppressionComment
-                let range = suppression.comments[0].range;
-                if unmatched_ranges.insert(range) {
-                    context.report_diagnostic_if_enabled(UnmatchedSuppressionComment {}, range);
+                if unmatched_ranges.insert(comment.range) {
+                    context.report_diagnostic_if_enabled(
+                        UnmatchedSuppressionComment {},
+                        comment.range,
+                    );
                 }
             }
         }
@@ -267,6 +277,35 @@ impl Suppressions {
         }
     }
 
+    fn report_suppression<T: Violation>(
+        context: &LintContext,
+        locator: &Locator,
+        suppression: &Suppression,
+        highlight_only_code: bool,
+        kind: T,
+    ) {
+        let disable_comment = suppression.comments.disable_comment();
+        let (range, edit) = Suppressions::delete_code_or_comment(
+            locator,
+            suppression,
+            disable_comment,
+            highlight_only_code,
+        );
+        let mut diagnostic = context.report_diagnostic(kind, range);
+        if let Some(enable_comment) = suppression.comments.enable_comment() {
+            let (enable_range, enable_range_edit) = Suppressions::delete_code_or_comment(
+                locator,
+                suppression,
+                enable_comment,
+                highlight_only_code,
+            );
+            diagnostic.secondary_annotation("", enable_range);
+            diagnostic.set_fix(Fix::safe_edits(edit, [enable_range_edit]));
+        } else {
+            diagnostic.set_fix(Fix::safe_edit(edit));
+        }
+    }
+
     fn delete_code_or_comment(
         locator: &Locator<'_>,
         suppression: &Suppression,
@@ -424,7 +463,10 @@ impl<'a> SuppressionsBuilder<'a> {
                     self.valid.push(Suppression {
                         code: code.into(),
                         range: combined_range,
-                        comments: smallvec![comment.comment.clone(), other.comment.clone()],
+                        comments: DisableEnableComments::DisableEnable(
+                            comment.comment.clone(),
+                            other.comment.clone(),
+                        ),
                         used: false.into(),
                     });
                 }
@@ -441,7 +483,7 @@ impl<'a> SuppressionsBuilder<'a> {
                     self.valid.push(Suppression {
                         code: code.into(),
                         range: implicit_range,
-                        comments: smallvec![comment.comment.clone()],
+                        comments: DisableEnableComments::Disable(comment.comment.clone()),
                         used: false.into(),
                     });
                 }
@@ -643,7 +685,7 @@ mod tests {
     use insta::assert_debug_snapshot;
     use itertools::Itertools;
     use ruff_python_parser::{Mode, ParseOptions, parse};
-    use ruff_text_size::{TextRange, TextSize};
+    use ruff_text_size::{TextLen, TextRange, TextSize};
     use similar::DiffableStr;
 
     use crate::{
@@ -705,24 +747,22 @@ print('hello')
                 Suppression {
                     covered_source: "# ruff: disable[foo]\nprint('hello')\n# ruff: enable[foo]",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[foo]",
-                            action: Enable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[foo]",
+                        action: Enable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
                 },
             ],
             invalid: [],
@@ -751,30 +791,28 @@ def foo():
                 Suppression {
                     covered_source: "# ruff: disable[bar]\n    print('hello')\n\n",
                     code: "bar",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[bar]",
-                            action: Disable,
-                            codes: [
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[bar]",
+                        action: Disable,
+                        codes: [
+                            "bar",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: None,
                 },
                 Suppression {
                     covered_source: "# ruff: disable[foo]\nprint('hello')\n\ndef foo():\n    # ruff: disable[bar]\n    print('hello')\n\n",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: None,
                 },
             ],
             invalid: [],
@@ -803,46 +841,42 @@ class Foo:
                 Suppression {
                     covered_source: "# ruff: disable[bar]\n        print('hello')\n        # ruff: enable[bar]",
                     code: "bar",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[bar]",
-                            action: Disable,
-                            codes: [
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[bar]",
-                            action: Enable,
-                            codes: [
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[bar]",
+                        action: Disable,
+                        codes: [
+                            "bar",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[bar]",
+                        action: Enable,
+                        codes: [
+                            "bar",
+                        ],
+                        reason: "",
+                    },
                 },
                 Suppression {
                     covered_source: "# ruff: disable[foo]\n    def bar(self):\n        # ruff: disable[bar]\n        print('hello')\n        # ruff: enable[bar]\n    # ruff: enable[foo]",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[foo]",
-                            action: Enable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[foo]",
+                        action: Enable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
                 },
             ],
             invalid: [],
@@ -872,46 +906,42 @@ def foo():
                 Suppression {
                     covered_source: "# ruff: disable[foo]\n    print('hello')\n    # ruff: disable[bar]\n    print('hello')\n    # ruff: enable[foo]",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[foo]",
-                            action: Enable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[foo]",
+                        action: Enable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
                 },
                 Suppression {
                     covered_source: "# ruff: disable[bar]\n    print('hello')\n    # ruff: enable[foo]\n    print('hello')\n    # ruff: enable[bar]",
                     code: "bar",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[bar]",
-                            action: Disable,
-                            codes: [
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[bar]",
-                            action: Enable,
-                            codes: [
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[bar]",
+                        action: Disable,
+                        codes: [
+                            "bar",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[bar]",
+                        action: Enable,
+                        codes: [
+                            "bar",
+                        ],
+                        reason: "",
+                    },
                 },
             ],
             invalid: [],
@@ -936,50 +966,46 @@ print('hello')
                 Suppression {
                     covered_source: "# ruff: disable[foo, bar]\nprint('hello')\n# ruff: enable[foo, bar]",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo, bar]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[foo, bar]",
-                            action: Enable,
-                            codes: [
-                                "foo",
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo, bar]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                            "bar",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[foo, bar]",
+                        action: Enable,
+                        codes: [
+                            "foo",
+                            "bar",
+                        ],
+                        reason: "",
+                    },
                 },
                 Suppression {
                     covered_source: "# ruff: disable[foo, bar]\nprint('hello')\n# ruff: enable[foo, bar]",
                     code: "bar",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo, bar]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[foo, bar]",
-                            action: Enable,
-                            codes: [
-                                "foo",
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo, bar]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                            "bar",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[foo, bar]",
+                        action: Enable,
+                        codes: [
+                            "foo",
+                            "bar",
+                        ],
+                        reason: "",
+                    },
                 },
             ],
             invalid: [],
@@ -1005,16 +1031,15 @@ print('world')
                 Suppression {
                     covered_source: "# ruff: disable[foo]\nprint('hello')\n# ruff: enable[bar]\nprint('world')\n",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: None,
                 },
             ],
             invalid: [
@@ -1051,32 +1076,30 @@ print('hello')
                 Suppression {
                     covered_source: "# ruff: disable[foo, bar]\nprint('hello')\n# ruff: enable[bar, foo]\n",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo, bar]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo, bar]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                            "bar",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: None,
                 },
                 Suppression {
                     covered_source: "# ruff: disable[foo, bar]\nprint('hello')\n# ruff: enable[bar, foo]\n",
                     code: "bar",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo, bar]",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                                "bar",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo, bar]",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                            "bar",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: None,
                 },
             ],
             invalid: [
@@ -1116,38 +1139,35 @@ print('hello')
                 Suppression {
                     covered_source: "# ruff: disable[foo] first\nprint('hello')\n# ruff: disable[foo] second\nprint('hello')\n# ruff: enable[foo]",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo] first",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "first",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[foo]",
-                            action: Enable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo] first",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "first",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[foo]",
+                        action: Enable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "",
+                    },
                 },
                 Suppression {
                     covered_source: "# ruff: disable[foo] second\nprint('hello')\n# ruff: enable[foo]\n",
                     code: "foo",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[foo] second",
-                            action: Disable,
-                            codes: [
-                                "foo",
-                            ],
-                            reason: "second",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[foo] second",
+                        action: Disable,
+                        codes: [
+                            "foo",
+                        ],
+                        reason: "second",
+                    },
+                    enable_comment: None,
                 },
             ],
             invalid: [],
@@ -1189,100 +1209,92 @@ def bar():
                 Suppression {
                     covered_source: "# ruff: disable[delta] unmatched\n        pass\n    # ruff: enable[beta,gamma]\n# ruff: enable[alpha]\n\n# ruff: disable  # parse error!\n",
                     code: "delta",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[delta] unmatched",
-                            action: Disable,
-                            codes: [
-                                "delta",
-                            ],
-                            reason: "unmatched",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[delta] unmatched",
+                        action: Disable,
+                        codes: [
+                            "delta",
+                        ],
+                        reason: "unmatched",
+                    },
+                    enable_comment: None,
                 },
                 Suppression {
                     covered_source: "# ruff: disable[beta,gamma]\n    if True:\n        # ruff: disable[delta] unmatched\n        pass\n    # ruff: enable[beta,gamma]",
                     code: "beta",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[beta,gamma]",
-                            action: Disable,
-                            codes: [
-                                "beta",
-                                "gamma",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[beta,gamma]",
-                            action: Enable,
-                            codes: [
-                                "beta",
-                                "gamma",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[beta,gamma]",
+                        action: Disable,
+                        codes: [
+                            "beta",
+                            "gamma",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[beta,gamma]",
+                        action: Enable,
+                        codes: [
+                            "beta",
+                            "gamma",
+                        ],
+                        reason: "",
+                    },
                 },
                 Suppression {
                     covered_source: "# ruff: disable[beta,gamma]\n    if True:\n        # ruff: disable[delta] unmatched\n        pass\n    # ruff: enable[beta,gamma]",
                     code: "gamma",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[beta,gamma]",
-                            action: Disable,
-                            codes: [
-                                "beta",
-                                "gamma",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[beta,gamma]",
-                            action: Enable,
-                            codes: [
-                                "beta",
-                                "gamma",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[beta,gamma]",
+                        action: Disable,
+                        codes: [
+                            "beta",
+                            "gamma",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[beta,gamma]",
+                        action: Enable,
+                        codes: [
+                            "beta",
+                            "gamma",
+                        ],
+                        reason: "",
+                    },
                 },
                 Suppression {
                     covered_source: "# ruff: disable[zeta] unmatched\n    pass\n# ruff: enable[zeta] underindented\n    pass\n",
                     code: "zeta",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[zeta] unmatched",
-                            action: Disable,
-                            codes: [
-                                "zeta",
-                            ],
-                            reason: "unmatched",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[zeta] unmatched",
+                        action: Disable,
+                        codes: [
+                            "zeta",
+                        ],
+                        reason: "unmatched",
+                    },
+                    enable_comment: None,
                 },
                 Suppression {
                     covered_source: "# ruff: disable[alpha]\ndef foo():\n    # ruff: disable[beta,gamma]\n    if True:\n        # ruff: disable[delta] unmatched\n        pass\n    # ruff: enable[beta,gamma]\n# ruff: enable[alpha]",
                     code: "alpha",
-                    comments: [
-                        SuppressionComment {
-                            text: "# ruff: disable[alpha]",
-                            action: Disable,
-                            codes: [
-                                "alpha",
-                            ],
-                            reason: "",
-                        },
-                        SuppressionComment {
-                            text: "# ruff: enable[alpha]",
-                            action: Enable,
-                            codes: [
-                                "alpha",
-                            ],
-                            reason: "",
-                        },
-                    ],
+                    disable_comment: SuppressionComment {
+                        text: "# ruff: disable[alpha]",
+                        action: Disable,
+                        codes: [
+                            "alpha",
+                        ],
+                        reason: "",
+                    },
+                    enable_comment: SuppressionComment {
+                        text: "# ruff: enable[alpha]",
+                        action: Enable,
+                        codes: [
+                            "alpha",
+                        ],
+                        reason: "",
+                    },
                 },
             ],
             invalid: [
@@ -1532,10 +1544,8 @@ def bar():
     #[test]
     fn comment_attributes() {
         let source = "# ruff: disable[foo, bar] hello world";
-        let mut parser = SuppressionParser::new(
-            source,
-            TextRange::new(0.into(), TextSize::try_from(source.len()).unwrap()),
-        );
+        let mut parser =
+            SuppressionParser::new(source, TextRange::new(0.into(), source.text_len()));
         let comment = parser.parse_comment().unwrap();
         assert_eq!(comment.action, SuppressionAction::Disable);
         assert_eq!(
@@ -1554,12 +1564,12 @@ def bar():
         source: &'_ str,
     ) -> Result<DebugSuppressionComment<'_>, ParseError> {
         let offset = TextSize::new(source.find('#').unwrap_or(0).try_into().unwrap());
-        let mut parser = SuppressionParser::new(
-            source,
-            TextRange::new(offset, TextSize::try_from(source.len()).unwrap()),
-        );
+        let mut parser = SuppressionParser::new(source, TextRange::new(offset, source.text_len()));
         match parser.parse_comment() {
-            Ok(comment) => Ok(DebugSuppressionComment { source, comment }),
+            Ok(comment) => Ok(DebugSuppressionComment {
+                source,
+                comment: Some(comment),
+            }),
             Err(error) => Err(error),
         }
     }
@@ -1639,16 +1649,18 @@ def bar():
                 .field("covered_source", &&self.source[self.suppression.range])
                 .field("code", &self.suppression.code)
                 .field(
-                    "comments",
-                    &self
-                        .suppression
-                        .comments
-                        .iter()
-                        .map(|comment| DebugSuppressionComment {
-                            source: self.source,
-                            comment: comment.clone(),
-                        })
-                        .collect_vec(),
+                    "disable_comment",
+                    &DebugSuppressionComment {
+                        source: self.source,
+                        comment: Some(self.suppression.comments.disable_comment().clone()),
+                    },
+                )
+                .field(
+                    "enable_comment",
+                    &DebugSuppressionComment {
+                        source: self.source,
+                        comment: self.suppression.comments.enable_comment().cloned(),
+                    },
                 )
                 .finish()
         }
@@ -1667,7 +1679,7 @@ def bar():
                     "comment",
                     &DebugSuppressionComment {
                         source: self.source,
-                        comment: self.invalid.comment.clone(),
+                        comment: Some(self.invalid.comment.clone()),
                     },
                 )
                 .finish()
@@ -1690,23 +1702,27 @@ def bar():
 
     struct DebugSuppressionComment<'a> {
         source: &'a str,
-        comment: SuppressionComment,
+        comment: Option<SuppressionComment>,
     }
 
     impl fmt::Debug for DebugSuppressionComment<'_> {
         fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-            f.debug_struct("SuppressionComment")
-                .field("text", &&self.source[self.comment.range])
-                .field("action", &self.comment.action)
-                .field(
-                    "codes",
-                    &DebugCodes {
-                        source: self.source,
-                        codes: &self.comment.codes,
-                    },
-                )
-                .field("reason", &&self.source[self.comment.reason])
-                .finish()
+            match &self.comment {
+                Some(comment) => f
+                    .debug_struct("SuppressionComment")
+                    .field("text", &&self.source[comment.range])
+                    .field("action", &comment.action)
+                    .field(
+                        "codes",
+                        &DebugCodes {
+                            source: self.source,
+                            codes: &comment.codes,
+                        },
+                    )
+                    .field("reason", &&self.source[comment.reason])
+                    .finish(),
+                None => f.debug_tuple("None").finish(),
+            }
         }
     }
 

crates/ruff_python_ast/src/python_version.rs

@@ -35,6 +35,10 @@ impl PythonVersion {
         major: 3,
         minor: 14,
     };
+    pub const PY315: PythonVersion = PythonVersion {
+        major: 3,
+        minor: 15,
+    };
 
     pub fn iter() -> impl Iterator<Item = PythonVersion> {
         [
@@ -46,6 +50,7 @@ impl PythonVersion {
             PythonVersion::PY312,
             PythonVersion::PY313,
             PythonVersion::PY314,
+            PythonVersion::PY315,
         ]
         .into_iter()
     }
@@ -61,7 +66,7 @@ impl PythonVersion {
 
     /// The latest Python version supported in preview
     pub fn latest_preview() -> Self {
-        let latest_preview = Self::PY314;
+        let latest_preview = Self::PY315;
         debug_assert!(latest_preview >= Self::latest());
         latest_preview
     }

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtonoff.py

@@ -91,20 +91,22 @@ def example(session):
         .all()
     # fmt: on
 def off_and_on_without_data():
-    """All comments here are technically on the same prefix.
-
-    The comments between will be formatted. This is a known limitation.
-    """
+    """Test that comment-only fmt:off/on blocks preserve formatting."""
+    # fmt: off
+            #should not be formatted
+    # fmt: on
     # fmt: off
 
-
-        #hey, that won't work
-
+        #should not be formatted
 
     # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
+    # fmt: on
     pass
-def on_and_off_broken():
-    """Another known limitation."""
+def on_and_off_with_comment_only_blocks():
+    """Test that fmt:off/on works with multiple directives and comment-only blocks."""
     # fmt: on
     # fmt: off
     this=should.not_be.formatted()
@@ -113,7 +115,16 @@ def on_and_off_broken():
     now . considers . multiple . fmt . directives . within . one . prefix
     # fmt: on
     # fmt: off
-        # ...but comments still get reformatted even though they should not be
+            #should not be formatted
+    # fmt: on
+    # fmt: off
+
+        #should not be formatted
+
+    # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
     # fmt: on
 def long_lines():
     if True:
@@ -178,6 +189,50 @@ cfg.rule(
     # fmt: on
     xxxxxxxxxx_xxxxxxxxxxx_xxxxxxx_xxxxxxxxx=5
 )
+
+# Test comment-only blocks at file level with various spacing patterns
+# fmt: off
+ #nospace
+ # twospaces
+# fmt: on
+
+
+# fmt: off
+#nospaceatall
+  #extraspaces
+   #evenmorespaces
+# fmt: on
+
+
+# fmt: off
+# fmt: on
+
+
+# fmt: off
+#SBATCH --job-name=test
+#SBATCH --output=test.out
+# fmt: on
+
+
+# fmt: off
+ #first
+
+ #second
+# fmt: on
+
+
+# fmt: off
+  #!@#$%^&*()
+   #<=>+-*/
+# fmt: on
+
+
+# fmt: off
+ #x=1+2
+  #y  =  3
+   #z    =    4
+# fmt: on
+
 # fmt: off
 yield  'hello'
 # No formatting to the end of the file

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtonoff.py.expect

@@ -112,29 +112,42 @@ def example(session):
 
 
 def off_and_on_without_data():
-    """All comments here are technically on the same prefix.
-
-    The comments between will be formatted. This is a known limitation.
-    """
+    """Test that comment-only fmt:off/on blocks preserve formatting."""
+    # fmt: off
+            #should not be formatted
+    # fmt: on
     # fmt: off
 
-    # hey, that won't work
+        #should not be formatted
 
     # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
+    # fmt: on
     pass
 
 
-def on_and_off_broken():
-    """Another known limitation."""
+def on_and_off_with_comment_only_blocks():
+    """Test that fmt:off/on works with multiple directives and comment-only blocks."""
     # fmt: on
     # fmt: off
     this=should.not_be.formatted()
     and_=indeed . it  is  not  formatted
     because . the . handling . inside . generate_ignored_nodes()
     now . considers . multiple . fmt . directives . within . one . prefix
+
+    # fmt: off
+            #should not be formatted
     # fmt: on
     # fmt: off
-    # ...but comments still get reformatted even though they should not be
+
+        #should not be formatted
+
+    # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
     # fmt: on
 
 
@@ -211,6 +224,50 @@ cfg.rule(
     # fmt: on
     xxxxxxxxxx_xxxxxxxxxxx_xxxxxxx_xxxxxxxxx=5,
 )
+
+# Test comment-only blocks at file level with various spacing patterns
+# fmt: off
+ #nospace
+ # twospaces
+# fmt: on
+
+
+# fmt: off
+#nospaceatall
+  #extraspaces
+   #evenmorespaces
+# fmt: on
+
+
+# fmt: off
+# fmt: on
+
+
+# fmt: off
+#SBATCH --job-name=test
+#SBATCH --output=test.out
+# fmt: on
+
+
+# fmt: off
+ #first
+
+ #second
+# fmt: on
+
+
+# fmt: off
+  #!@#$%^&*()
+   #<=>+-*/
+# fmt: on
+
+
+# fmt: off
+ #x=1+2
+  #y  =  3
+   #z    =    4
+# fmt: on
+
 # fmt: off
 yield  'hello'
 # No formatting to the end of the file

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip10.py

@@ -1,8 +1,21 @@
 def foo(): return "mock"  # fmt: skip
 if True: print("yay")  # fmt: skip
 for i in range(10): print(i)  # fmt: skip
+if True: print("this"); print("that")  # fmt: skip
+while True: print("loop"); break  # fmt: skip
+for x in [1, 2]: print(x); print("done")  # fmt: skip
+def f(x: int): return x # fmt: skip
 
 j =     1 # fmt: skip
 while j < 10: j += 1  # fmt: skip
 
 b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"] # fmt: skip
+
+v = (
+    foo_dict  # fmt: skip
+    .setdefault("a", {})
+    .setdefault("b", {})
+    .setdefault("c", {})
+    .setdefault("d", {})
+    .setdefault("e", {})
+)

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip10.py.expect

@@ -1,8 +1,21 @@
 def foo(): return "mock"  # fmt: skip
 if True: print("yay")  # fmt: skip
 for i in range(10): print(i)  # fmt: skip
+if True: print("this"); print("that")  # fmt: skip
+while True: print("loop"); break  # fmt: skip
+for x in [1, 2]: print(x); print("done")  # fmt: skip
+def f(x: int): return x # fmt: skip
 
 j =     1 # fmt: skip
 while j < 10: j += 1  # fmt: skip
 
 b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"] # fmt: skip
+
+v = (
+    foo_dict  # fmt: skip
+    .setdefault("a", {})
+    .setdefault("b", {})
+    .setdefault("c", {})
+    .setdefault("d", {})
+    .setdefault("e", {})
+)

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip11.py

@@ -4,3 +4,84 @@ def foo():
 
 # comment 1  # fmt: skip
 # comment 2
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+if False:
+    # fmt: off # some other comment
+    pass

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip11.py.expect

@@ -4,3 +4,84 @@ def foo():
 
 # comment 1  # fmt: skip
 # comment 2
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+if False:
+    # fmt: off # some other comment
+    pass

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip12.options.json

@@ -0,0 +1 @@
+{"preview": "enabled"}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip12.py

@@ -0,0 +1,8 @@
+with open("file.txt") as f:    content = f.read() # fmt: skip
+
+# Ideally, only the last line would be ignored
+# But ignoring only part of the asexpr_test causes a parse error
+# Same with ignoring the asexpr_test without also ignoring the entire with_stmt
+with open   (
+    "file.txt"   ,
+) as f:    content = f.read() # fmt: skip

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip12.py.expect

@@ -0,0 +1,8 @@
+with open("file.txt") as f:    content = f.read() # fmt: skip
+
+# Ideally, only the last line would be ignored
+# But ignoring only part of the asexpr_test causes a parse error
+# Same with ignoring the asexpr_test without also ignoring the entire with_stmt
+with open   (
+    "file.txt"   ,
+) as f:    content = f.read() # fmt: skip

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip13.options.json

@@ -0,0 +1 @@
+{"preview": "enabled"}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip13.py

@@ -0,0 +1,28 @@
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {"foo": "bar"},
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar"},
+)
+
+
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {"foo": "bar",},
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar",},
+)

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip13.py.expect

@@ -0,0 +1,32 @@
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {"foo": "bar"},
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar"},
+)
+
+
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {
+        "foo": "bar",
+    },
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {
+        "foo": "bar",
+    },
+)

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip7.py

@@ -1,4 +1,4 @@
 a =     "this is some code"
-b =     5  #fmt:skip
+b =     5          # fmt:skip
 c = 9  #fmt: skip
-d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  #fmt:skip
+d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  #            fmt:skip

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip7.py.expect

@@ -1,4 +1,4 @@
 a = "this is some code"
-b =     5  # fmt:skip
-c = 9  # fmt: skip
-d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  # fmt:skip
+b =     5          # fmt:skip
+c = 9  #fmt: skip
+d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  #            fmt:skip

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip_multiple_in_clause.py

@@ -0,0 +1,19 @@
+# Multiple fmt: skip in multi-part if-clause
+class ClassWithALongName:
+    Constant1 = 1
+    Constant2 = 2
+    Constant3 = 3
+
+
+def test():
+    if (
+        "cond1" == "cond1"
+        and "cond2" == "cond2"
+        and 1 in (
+            ClassWithALongName.Constant1,
+            ClassWithALongName.Constant2,
+            ClassWithALongName.Constant3, # fmt: skip
+        ) # fmt: skip
+    ):
+        return True
+    return False

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip_multiple_in_clause.py.expect

@@ -0,0 +1,19 @@
+# Multiple fmt: skip in multi-part if-clause
+class ClassWithALongName:
+    Constant1 = 1
+    Constant2 = 2
+    Constant3 = 3
+
+
+def test():
+    if (
+        "cond1" == "cond1"
+        and "cond2" == "cond2"
+        and 1 in (
+            ClassWithALongName.Constant1,
+            ClassWithALongName.Constant2,
+            ClassWithALongName.Constant3, # fmt: skip
+        ) # fmt: skip
+    ):
+        return True
+    return False

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip_multiple_strings.py

@@ -0,0 +1,35 @@
+# Multiple fmt: skip on string literals
+a = (
+    "this should "  # fmt: skip
+    "be fine"
+)
+
+b = (
+    "this is "  # fmt: skip
+    "not working"  # fmt: skip
+)
+
+c = (
+    "and neither "  # fmt: skip
+    "is this "  # fmt: skip
+    "working"
+)
+
+d = (
+    "nor "
+    "is this "  # fmt: skip
+    "working"  # fmt: skip
+)
+
+e = (
+    "and this "  # fmt: skip
+    "is definitely "
+    "not working"  # fmt: skip
+)
+
+# Dictionary entries with fmt: skip (covers issue with long lines)
+hotkeys = {
+    "editor:swap-line-down": [{"key": "ArrowDown", "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:swap-line-up":   [{"key": "ArrowUp",   "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:toggle-source":  [{"key": "S",         "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip_multiple_strings.py.expect

@@ -0,0 +1,35 @@
+# Multiple fmt: skip on string literals
+a = (
+    "this should "  # fmt: skip
+    "be fine"
+)
+
+b = (
+    "this is "  # fmt: skip
+    "not working"  # fmt: skip
+)
+
+c = (
+    "and neither "  # fmt: skip
+    "is this "  # fmt: skip
+    "working"
+)
+
+d = (
+    "nor "
+    "is this "  # fmt: skip
+    "working"  # fmt: skip
+)
+
+e = (
+    "and this "  # fmt: skip
+    "is definitely "
+    "not working"  # fmt: skip
+)
+
+# Dictionary entries with fmt: skip (covers issue with long lines)
+hotkeys = {
+    "editor:swap-line-down": [{"key": "ArrowDown", "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:swap-line-up":   [{"key": "ArrowUp",   "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:toggle-source":  [{"key": "S",         "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/jupytext_markdown_fmt.py

@@ -0,0 +1,24 @@
+# Test that Jupytext markdown comments are preserved before fmt:off/on blocks
+# %% [markdown]
+
+# fmt: off
+# fmt: on
+
+# Also test with other comments
+# Some comment
+# %% [markdown]
+# Another comment
+
+# fmt: off
+x = 1
+# fmt: on
+
+# Test multiple markdown comments
+# %% [markdown]
+# First markdown
+# %% [code]
+# Code cell
+
+# fmt: off
+y = 2
+# fmt: on

crates/ruff_python_formatter/resources/test/fixtures/black/cases/jupytext_markdown_fmt.py.expect

@@ -0,0 +1,24 @@
+# Test that Jupytext markdown comments are preserved before fmt:off/on blocks
+# %% [markdown]
+
+# fmt: off
+# fmt: on
+
+# Also test with other comments
+# Some comment
+# %% [markdown]
+# Another comment
+
+# fmt: off
+x = 1
+# fmt: on
+
+# Test multiple markdown comments
+# %% [markdown]
+# First markdown
+# %% [code]
+# Code cell
+
+# fmt: off
+y = 2
+# fmt: on

crates/ruff_python_formatter/resources/test/fixtures/black/cases/pep_750.options.json

@@ -0,0 +1 @@
+{"target_version": "3.14"}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/pep_750.py

@@ -0,0 +1,40 @@
+x = t"foo"
+x = t'foo {{ {2 + 2}bar {{ baz'
+
+x = t"foo {f'abc'} bar"
+
+x = t"""foo {{ a
+    foo {2 + 2}bar {{ baz
+
+    x = f"foo {{ {
+        2 + 2  # comment
+    }bar"
+
+    {{ baz
+
+    }} buzz
+
+    {print("abc" + "def"
+)}
+abc"""
+
+t'{(abc:=10)}'
+
+t'''This is a really long string, but just make sure that you reflow tstrings {
+    2+2:d
+}'''
+t'This is a really long string, but just make sure that you reflow tstrings correctly {2+2:d}'
+
+t"{     2      +     2    =    }"
+
+t'{
+X
+!r
+}'
+
+tr'\{{\}}'
+
+t'''
+    WITH {f'''
+    {1}_cte AS ()'''}
+'''

crates/ruff_python_formatter/resources/test/fixtures/black/cases/pep_750.py.expect

@@ -0,0 +1,40 @@
+x = t"foo"
+x = t"foo {{ {2 + 2}bar {{ baz"
+
+x = t"foo {f'abc'} bar"
+
+x = t"""foo {{ a
+    foo {2 + 2}bar {{ baz
+
+    x = f"foo {{ {
+        2 + 2  # comment
+    }bar"
+
+    {{ baz
+
+    }} buzz
+
+    {print("abc" + "def"
+)}
+abc"""
+
+t"{(abc:=10)}"
+
+t"""This is a really long string, but just make sure that you reflow tstrings {
+    2+2:d
+}"""
+t"This is a really long string, but just make sure that you reflow tstrings correctly {2+2:d}"
+
+t"{     2      +     2    =    }"
+
+t"{
+X
+!r
+}"
+
+rt"\{{\}}"
+
+t"""
+    WITH {f'''
+    {1}_cte AS ()'''}
+"""

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_fmtpass_imports.options.json

@@ -0,0 +1 @@
+{"preview": "enabled"}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_fmtpass_imports.py

@@ -0,0 +1,19 @@
+# Regression test for https://github.com/psf/black/issues/3438
+
+import ast
+import collections  # fmt: skip
+import dataclasses
+# fmt: off
+import os
+# fmt: on
+import pathlib
+
+import re  # fmt: skip
+import secrets
+
+# fmt: off
+import sys
+# fmt: on
+
+import tempfile
+import zoneinfo

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_fmtpass_imports.py.expect

@@ -0,0 +1,19 @@
+# Regression test for https://github.com/psf/black/issues/3438
+
+import ast
+import collections  # fmt: skip
+import dataclasses
+# fmt: off
+import os
+# fmt: on
+import pathlib
+
+import re  # fmt: skip
+import secrets
+
+# fmt: off
+import sys
+# fmt: on
+
+import tempfile
+import zoneinfo

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_multiline_strings.py

@@ -156,24 +156,6 @@ Please use `--build-option` instead,
 `--global-option` is reserved to flags like `--verbose` or `--quiet`.
 """
 
-this_will_become_one_line = (
-    "a"
-    "b"
-    "c"
-)
-
-this_will_stay_on_three_lines = (
-    "a"  # comment
-    "b"
-    "c"
-)
-
-this_will_also_become_one_line = (  # comment
-    "a"
-    "b"
-    "c"
-)
-
 assert some_var == expected_result, """
 test
 """

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_multiline_strings.py.expect

@@ -198,16 +198,6 @@ Please use `--build-option` instead,
 `--global-option` is reserved to flags like `--verbose` or `--quiet`.
 """
 
-this_will_become_one_line = "abc"
-
-this_will_stay_on_three_lines = (
-    "a"  # comment
-    "b"
-    "c"
-)
-
-this_will_also_become_one_line = "abc"  # comment
-
 assert some_var == expected_result, """
 test
 """

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_standardize_type_comments.options.json

@@ -0,0 +1 @@
+{"preview": "enabled"}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_standardize_type_comments.py

@@ -0,0 +1,10 @@
+def foo(
+    a, #type:int
+    b, #type: str
+    c, # type: List[int]
+    d, #  type:  Dict[int, str]
+    e, #       type:     ignore
+    f, # type : ignore
+    g, #  type : ignore
+):
+    pass

crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_standardize_type_comments.py.expect

@@ -0,0 +1,10 @@
+def foo(
+    a,  # type: int
+    b,  # type: str
+    c,  # type: List[int]
+    d,  # type: Dict[int, str]
+    e,  # type: ignore
+    f,  # type : ignore
+    g,  #  type : ignore
+):
+    pass

crates/ruff_python_formatter/resources/test/fixtures/black/cases/remove_parens_from_lhs.options.json

@@ -0,0 +1 @@
+{"preview": "enabled"}

crates/ruff_python_formatter/resources/test/fixtures/black/cases/remove_parens_from_lhs.py

@@ -0,0 +1,16 @@
+# Remove unnecessary parentheses from LHS of assignments
+
+
+def a():
+    return [1, 2, 3]
+
+
+# Single variable with unnecessary parentheses
+(b) = a()[0]
+
+# Tuple unpacking with unnecessary parentheses
+(c, *_) = a()
+
+# These should not be changed - parentheses are necessary
+(d,) = a()  # single-element tuple
+e = (1 + 2) * 3  # RHS has precedence needs

crates/ruff_python_formatter/resources/test/fixtures/black/cases/remove_parens_from_lhs.py.expect

@@ -0,0 +1,16 @@
+# Remove unnecessary parentheses from LHS of assignments
+
+
+def a():
+    return [1, 2, 3]
+
+
+# Single variable with unnecessary parentheses
+b = a()[0]
+
+# Tuple unpacking with unnecessary parentheses
+c, *_ = a()
+
+# These should not be changed - parentheses are necessary
+(d,) = a()  # single-element tuple
+e = (1 + 2) * 3  # RHS has precedence needs

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtonoff.py.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff_python_formatter/tests/fixtures.rs
-input_file: crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtonoff.py
 ---
 ## Input
 
@@ -98,20 +97,22 @@ def example(session):
         .all()
     # fmt: on
 def off_and_on_without_data():
-    """All comments here are technically on the same prefix.
-
-    The comments between will be formatted. This is a known limitation.
-    """
+    """Test that comment-only fmt:off/on blocks preserve formatting."""
+    # fmt: off
+            #should not be formatted
+    # fmt: on
     # fmt: off
 
-
-        #hey, that won't work
-
+        #should not be formatted
 
     # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
+    # fmt: on
     pass
-def on_and_off_broken():
-    """Another known limitation."""
+def on_and_off_with_comment_only_blocks():
+    """Test that fmt:off/on works with multiple directives and comment-only blocks."""
     # fmt: on
     # fmt: off
     this=should.not_be.formatted()
@@ -120,7 +121,16 @@ def on_and_off_broken():
     now . considers . multiple . fmt . directives . within . one . prefix
     # fmt: on
     # fmt: off
-        # ...but comments still get reformatted even though they should not be
+            #should not be formatted
+    # fmt: on
+    # fmt: off
+
+        #should not be formatted
+
+    # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
     # fmt: on
 def long_lines():
     if True:
@@ -185,6 +195,50 @@ cfg.rule(
     # fmt: on
     xxxxxxxxxx_xxxxxxxxxxx_xxxxxxx_xxxxxxxxx=5
 )
+
+# Test comment-only blocks at file level with various spacing patterns
+# fmt: off
+ #nospace
+ # twospaces
+# fmt: on
+
+
+# fmt: off
+#nospaceatall
+  #extraspaces
+   #evenmorespaces
+# fmt: on
+
+
+# fmt: off
+# fmt: on
+
+
+# fmt: off
+#SBATCH --job-name=test
+#SBATCH --output=test.out
+# fmt: on
+
+
+# fmt: off
+ #first
+
+ #second
+# fmt: on
+
+
+# fmt: off
+  #!@#$%^&*()
+   #<=>+-*/
+# fmt: on
+
+
+# fmt: off
+ #x=1+2
+  #y  =  3
+   #z    =    4
+# fmt: on
+
 # fmt: off
 yield  'hello'
 # No formatting to the end of the file
@@ -225,28 +279,16 @@ d={'a':1,
          # fmt: on
          goes + here,
          andhere,
-@@ -118,8 +119,10 @@
-     """
-     # fmt: off
- 
--    # hey, that won't work
- 
-+        #hey, that won't work
-+
-+
-     # fmt: on
-     pass
- 
-@@ -134,7 +137,7 @@
+@@ -136,7 +137,7 @@
+     and_=indeed . it  is  not  formatted
+     because . the . handling . inside . generate_ignored_nodes()
      now . considers . multiple . fmt . directives . within . one . prefix
-     # fmt: on
+-
++    # fmt: on
      # fmt: off
--    # ...but comments still get reformatted even though they should not be
-+        # ...but comments still get reformatted even though they should not be
+             #should not be formatted
      # fmt: on
- 
- 
-@@ -174,14 +177,18 @@
+@@ -187,14 +188,18 @@
          $
          """,
          # fmt: off
@@ -387,22 +429,24 @@ def example(session):
 
 
 def off_and_on_without_data():
-    """All comments here are technically on the same prefix.
-
-    The comments between will be formatted. This is a known limitation.
-    """
+    """Test that comment-only fmt:off/on blocks preserve formatting."""
+    # fmt: off
+            #should not be formatted
+    # fmt: on
     # fmt: off
 
+        #should not be formatted
 
-        #hey, that won't work
-
-
+    # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
     # fmt: on
     pass
 
 
-def on_and_off_broken():
-    """Another known limitation."""
+def on_and_off_with_comment_only_blocks():
+    """Test that fmt:off/on works with multiple directives and comment-only blocks."""
     # fmt: on
     # fmt: off
     this=should.not_be.formatted()
@@ -411,7 +455,16 @@ def on_and_off_broken():
     now . considers . multiple . fmt . directives . within . one . prefix
     # fmt: on
     # fmt: off
-        # ...but comments still get reformatted even though they should not be
+            #should not be formatted
+    # fmt: on
+    # fmt: off
+
+        #should not be formatted
+
+    # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
     # fmt: on
 
 
@@ -492,6 +545,50 @@ cfg.rule(
     # fmt: on
     xxxxxxxxxx_xxxxxxxxxxx_xxxxxxx_xxxxxxxxx=5,
 )
+
+# Test comment-only blocks at file level with various spacing patterns
+# fmt: off
+ #nospace
+ # twospaces
+# fmt: on
+
+
+# fmt: off
+#nospaceatall
+  #extraspaces
+   #evenmorespaces
+# fmt: on
+
+
+# fmt: off
+# fmt: on
+
+
+# fmt: off
+#SBATCH --job-name=test
+#SBATCH --output=test.out
+# fmt: on
+
+
+# fmt: off
+ #first
+
+ #second
+# fmt: on
+
+
+# fmt: off
+  #!@#$%^&*()
+   #<=>+-*/
+# fmt: on
+
+
+# fmt: off
+ #x=1+2
+  #y  =  3
+   #z    =    4
+# fmt: on
+
 # fmt: off
 yield  'hello'
 # No formatting to the end of the file
@@ -617,29 +714,42 @@ def example(session):
 
 
 def off_and_on_without_data():
-    """All comments here are technically on the same prefix.
-
-    The comments between will be formatted. This is a known limitation.
-    """
+    """Test that comment-only fmt:off/on blocks preserve formatting."""
+    # fmt: off
+            #should not be formatted
+    # fmt: on
     # fmt: off
 
-    # hey, that won't work
+        #should not be formatted
 
     # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
+    # fmt: on
     pass
 
 
-def on_and_off_broken():
-    """Another known limitation."""
+def on_and_off_with_comment_only_blocks():
+    """Test that fmt:off/on works with multiple directives and comment-only blocks."""
     # fmt: on
     # fmt: off
     this=should.not_be.formatted()
     and_=indeed . it  is  not  formatted
     because . the . handling . inside . generate_ignored_nodes()
     now . considers . multiple . fmt . directives . within . one . prefix
+
+    # fmt: off
+            #should not be formatted
     # fmt: on
     # fmt: off
-    # ...but comments still get reformatted even though they should not be
+
+        #should not be formatted
+
+    # fmt: on
+    # fmt: off
+            #should not be formatted
+        #should not be formatted #also should not be formatted
     # fmt: on
 
 
@@ -716,6 +826,50 @@ cfg.rule(
     # fmt: on
     xxxxxxxxxx_xxxxxxxxxxx_xxxxxxx_xxxxxxxxx=5,
 )
+
+# Test comment-only blocks at file level with various spacing patterns
+# fmt: off
+ #nospace
+ # twospaces
+# fmt: on
+
+
+# fmt: off
+#nospaceatall
+  #extraspaces
+   #evenmorespaces
+# fmt: on
+
+
+# fmt: off
+# fmt: on
+
+
+# fmt: off
+#SBATCH --job-name=test
+#SBATCH --output=test.out
+# fmt: on
+
+
+# fmt: off
+ #first
+
+ #second
+# fmt: on
+
+
+# fmt: off
+  #!@#$%^&*()
+   #<=>+-*/
+# fmt: on
+
+
+# fmt: off
+ #x=1+2
+  #y  =  3
+   #z    =    4
+# fmt: on
+
 # fmt: off
 yield  'hello'
 # No formatting to the end of the file

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtskip10.py.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff_python_formatter/tests/fixtures.rs
-input_file: crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmtskip10.py
 ---
 ## Input
 
@@ -8,11 +7,24 @@ input_file: crates/ruff_python_formatter/resources/test/fixtures/black/cases/fmt
 def foo(): return "mock"  # fmt: skip
 if True: print("yay")  # fmt: skip
 for i in range(10): print(i)  # fmt: skip
+if True: print("this"); print("that")  # fmt: skip
+while True: print("loop"); break  # fmt: skip
+for x in [1, 2]: print(x); print("done")  # fmt: skip
+def f(x: int): return x # fmt: skip
 
 j =     1 # fmt: skip
 while j < 10: j += 1  # fmt: skip
 
 b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"] # fmt: skip
+
+v = (
+    foo_dict  # fmt: skip
+    .setdefault("a", {})
+    .setdefault("b", {})
+    .setdefault("c", {})
+    .setdefault("d", {})
+    .setdefault("e", {})
+)
 ```
 
 ## Black Differences
@@ -20,19 +32,30 @@ b = [c for c in "A very long string that would normally generate some kind of co
 ```diff
 --- Black
 +++ Ruff
-@@ -1,8 +1,10 @@
+@@ -1,15 +1,20 @@
  def foo(): return "mock"  # fmt: skip
 +
 +
  if True: print("yay")  # fmt: skip
  for i in range(10): print(i)  # fmt: skip
+ if True: print("this"); print("that")  # fmt: skip
+ while True: print("loop"); break  # fmt: skip
+ for x in [1, 2]: print(x); print("done")  # fmt: skip
+-def f(x: int): return x # fmt: skip
  
 -j =     1 # fmt: skip
++
++def f(x: int): return x  # fmt: skip
++
++
 +j =     1  # fmt: skip
  while j < 10: j += 1  # fmt: skip
  
 -b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"] # fmt: skip
 +b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"]  # fmt: skip
+ 
+ v = (
+     foo_dict  # fmt: skip
 ```
 
 ## Ruff Output
@@ -43,11 +66,27 @@ def foo(): return "mock"  # fmt: skip
 
 if True: print("yay")  # fmt: skip
 for i in range(10): print(i)  # fmt: skip
+if True: print("this"); print("that")  # fmt: skip
+while True: print("loop"); break  # fmt: skip
+for x in [1, 2]: print(x); print("done")  # fmt: skip
+
+
+def f(x: int): return x  # fmt: skip
+
 
 j =     1  # fmt: skip
 while j < 10: j += 1  # fmt: skip
 
 b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"]  # fmt: skip
+
+v = (
+    foo_dict  # fmt: skip
+    .setdefault("a", {})
+    .setdefault("b", {})
+    .setdefault("c", {})
+    .setdefault("d", {})
+    .setdefault("e", {})
+)
 ```
 
 ## Black Output
@@ -56,9 +95,22 @@ b = [c for c in "A very long string that would normally generate some kind of co
 def foo(): return "mock"  # fmt: skip
 if True: print("yay")  # fmt: skip
 for i in range(10): print(i)  # fmt: skip
+if True: print("this"); print("that")  # fmt: skip
+while True: print("loop"); break  # fmt: skip
+for x in [1, 2]: print(x); print("done")  # fmt: skip
+def f(x: int): return x # fmt: skip
 
 j =     1 # fmt: skip
 while j < 10: j += 1  # fmt: skip
 
 b = [c for c in "A very long string that would normally generate some kind of collapse, since it is this long"] # fmt: skip
+
+v = (
+    foo_dict  # fmt: skip
+    .setdefault("a", {})
+    .setdefault("b", {})
+    .setdefault("c", {})
+    .setdefault("d", {})
+    .setdefault("e", {})
+)
 ```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtskip11.py.snap

@@ -0,0 +1,321 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+def foo():
+    pass
+
+
+# comment 1  # fmt: skip
+# comment 2
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+if False:
+    # fmt: off # some other comment
+    pass
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -46,8 +46,7 @@
+ [
+     (1, 2),
+     # # fmt: off
+-    (3,
+-       4),
++    (3, 4),
+     # # fmt: on
+     (5, 6),
+ ]
+@@ -55,8 +54,7 @@
+ [
+     (1, 2),
+     # # fmt: off
+-    (3,
+-       4),
++    (3, 4),
+     # fmt: on
+     (5, 6),
+ ]
+@@ -65,8 +63,7 @@
+ [
+     (1, 2),
+     # fmt: off
+-    (3,
+-       4),
++    (3, 4),
+     # # fmt: on
+     (5, 6),
+ ]
+@@ -75,8 +72,7 @@
+ [
+     (1, 2),
+     # fmt: off
+-    (3,
+-       4),
++    (3, 4),
+     # fmt: on
+     (5, 6),
+ ]
+```
+
+## Ruff Output
+
+```python
+def foo():
+    pass
+
+
+# comment 1  # fmt: skip
+# comment 2
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3, 4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3, 4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3, 4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3, 4),
+    # fmt: on
+    (5, 6),
+]
+
+
+if False:
+    # fmt: off # some other comment
+    pass
+```
+
+## Black Output
+
+```python
+def foo():
+    pass
+
+
+# comment 1  # fmt: skip
+# comment 2
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    # (3,
+    #    4),
+    # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+[
+    (1, 2),
+    # # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # # fmt: on
+    (5, 6),
+]
+
+
+[
+    (1, 2),
+    # fmt: off
+    (3,
+       4),
+    # fmt: on
+    (5, 6),
+]
+
+
+if False:
+    # fmt: off # some other comment
+    pass
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtskip12.py.snap

@@ -0,0 +1,59 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+with open("file.txt") as f:    content = f.read() # fmt: skip
+
+# Ideally, only the last line would be ignored
+# But ignoring only part of the asexpr_test causes a parse error
+# Same with ignoring the asexpr_test without also ignoring the entire with_stmt
+with open   (
+    "file.txt"   ,
+) as f:    content = f.read() # fmt: skip
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -1,8 +1,8 @@
+-with open("file.txt") as f:    content = f.read() # fmt: skip
++with open("file.txt") as f:    content = f.read()  # fmt: skip
+ 
+ # Ideally, only the last line would be ignored
+ # But ignoring only part of the asexpr_test causes a parse error
+ # Same with ignoring the asexpr_test without also ignoring the entire with_stmt
+ with open   (
+     "file.txt"   ,
+-) as f:    content = f.read() # fmt: skip
++) as f:    content = f.read()  # fmt: skip
+```
+
+## Ruff Output
+
+```python
+with open("file.txt") as f:    content = f.read()  # fmt: skip
+
+# Ideally, only the last line would be ignored
+# But ignoring only part of the asexpr_test causes a parse error
+# Same with ignoring the asexpr_test without also ignoring the entire with_stmt
+with open   (
+    "file.txt"   ,
+) as f:    content = f.read()  # fmt: skip
+```
+
+## Black Output
+
+```python
+with open("file.txt") as f:    content = f.read() # fmt: skip
+
+# Ideally, only the last line would be ignored
+# But ignoring only part of the asexpr_test causes a parse error
+# Same with ignoring the asexpr_test without also ignoring the entire with_stmt
+with open   (
+    "file.txt"   ,
+) as f:    content = f.read() # fmt: skip
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtskip13.py.snap

@@ -0,0 +1,149 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {"foo": "bar"},
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar"},
+)
+
+
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {"foo": "bar",},
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar",},
+)
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -1,5 +1,9 @@
+ t = (
+-    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
++    {
++        "foo": "very long string",
++        "bar": "another very long string",
++        "baz": "we should run out of space by now",
++    },  # fmt: skip
+     {"foo": "bar"},
+ )
+ 
+@@ -14,8 +18,12 @@
+ 
+ 
+ t = (
+-    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+     {
++        "foo": "very long string",
++        "bar": "another very long string",
++        "baz": "we should run out of space by now",
++    },  # fmt: skip
++    {
+         "foo": "bar",
+     },
+ )
+```
+
+## Ruff Output
+
+```python
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar"},
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar"},
+)
+
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {
+        "foo": "bar",
+    },
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {
+        "foo": "bar",
+    },
+)
+```
+
+## Black Output
+
+```python
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {"foo": "bar"},
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {"foo": "bar"},
+)
+
+
+t = (
+    {"foo": "very long string", "bar": "another very long string", "baz": "we should run out of space by now"},  # fmt: skip
+    {
+        "foo": "bar",
+    },
+)
+
+t = (
+    {
+        "foo": "very long string",
+        "bar": "another very long string",
+        "baz": "we should run out of space by now",
+    },  # fmt: skip
+    {
+        "foo": "bar",
+    },
+)
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtskip7.py.snap

@@ -0,0 +1,43 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+a =     "this is some code"
+b =     5          # fmt:skip
+c = 9  #fmt: skip
+d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  #            fmt:skip
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -1,4 +1,4 @@
+ a = "this is some code"
+-b =     5          # fmt:skip
+-c = 9  #fmt: skip
++b =     5  # fmt:skip
++c = 9  # fmt: skip
+ d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  #            fmt:skip
+```
+
+## Ruff Output
+
+```python
+a = "this is some code"
+b =     5  # fmt:skip
+c = 9  # fmt: skip
+d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  #            fmt:skip
+```
+
+## Black Output
+
+```python
+a = "this is some code"
+b =     5          # fmt:skip
+c = 9  #fmt: skip
+d = "thisisasuperlongstringthisisasuperlongstringthisisasuperlongstringthisisasuperlongstring"  #            fmt:skip
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtskip_multiple_in_clause.py.snap

@@ -0,0 +1,98 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+# Multiple fmt: skip in multi-part if-clause
+class ClassWithALongName:
+    Constant1 = 1
+    Constant2 = 2
+    Constant3 = 3
+
+
+def test():
+    if (
+        "cond1" == "cond1"
+        and "cond2" == "cond2"
+        and 1 in (
+            ClassWithALongName.Constant1,
+            ClassWithALongName.Constant2,
+            ClassWithALongName.Constant3, # fmt: skip
+        ) # fmt: skip
+    ):
+        return True
+    return False
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -9,11 +9,12 @@
+     if (
+         "cond1" == "cond1"
+         and "cond2" == "cond2"
+-        and 1 in (
++        and 1
++        in (
+             ClassWithALongName.Constant1,
+             ClassWithALongName.Constant2,
+-            ClassWithALongName.Constant3, # fmt: skip
+-        ) # fmt: skip
++            ClassWithALongName.Constant3,  # fmt: skip
++        )  # fmt: skip
+     ):
+         return True
+     return False
+```
+
+## Ruff Output
+
+```python
+# Multiple fmt: skip in multi-part if-clause
+class ClassWithALongName:
+    Constant1 = 1
+    Constant2 = 2
+    Constant3 = 3
+
+
+def test():
+    if (
+        "cond1" == "cond1"
+        and "cond2" == "cond2"
+        and 1
+        in (
+            ClassWithALongName.Constant1,
+            ClassWithALongName.Constant2,
+            ClassWithALongName.Constant3,  # fmt: skip
+        )  # fmt: skip
+    ):
+        return True
+    return False
+```
+
+## Black Output
+
+```python
+# Multiple fmt: skip in multi-part if-clause
+class ClassWithALongName:
+    Constant1 = 1
+    Constant2 = 2
+    Constant3 = 3
+
+
+def test():
+    if (
+        "cond1" == "cond1"
+        and "cond2" == "cond2"
+        and 1 in (
+            ClassWithALongName.Constant1,
+            ClassWithALongName.Constant2,
+            ClassWithALongName.Constant3, # fmt: skip
+        ) # fmt: skip
+    ):
+        return True
+    return False
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__fmtskip_multiple_strings.py.snap

@@ -0,0 +1,148 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+# Multiple fmt: skip on string literals
+a = (
+    "this should "  # fmt: skip
+    "be fine"
+)
+
+b = (
+    "this is "  # fmt: skip
+    "not working"  # fmt: skip
+)
+
+c = (
+    "and neither "  # fmt: skip
+    "is this "  # fmt: skip
+    "working"
+)
+
+d = (
+    "nor "
+    "is this "  # fmt: skip
+    "working"  # fmt: skip
+)
+
+e = (
+    "and this "  # fmt: skip
+    "is definitely "
+    "not working"  # fmt: skip
+)
+
+# Dictionary entries with fmt: skip (covers issue with long lines)
+hotkeys = {
+    "editor:swap-line-down": [{"key": "ArrowDown", "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:swap-line-up":   [{"key": "ArrowUp",   "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:toggle-source":  [{"key": "S",         "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+}
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -29,7 +29,11 @@
+ 
+ # Dictionary entries with fmt: skip (covers issue with long lines)
+ hotkeys = {
+-    "editor:swap-line-down": [{"key": "ArrowDown", "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+-    "editor:swap-line-up":   [{"key": "ArrowUp",   "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+-    "editor:toggle-source":  [{"key": "S",         "modifiers": ["Alt", "Mod"]}],  # fmt: skip
++    "editor:swap-line-down": [
++        {"key": "ArrowDown", "modifiers": ["Alt", "Mod"]}
++    ],  # fmt: skip
++    "editor:swap-line-up": [
++        {"key": "ArrowUp", "modifiers": ["Alt", "Mod"]}
++    ],  # fmt: skip
++    "editor:toggle-source": [{"key": "S", "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+ }
+```
+
+## Ruff Output
+
+```python
+# Multiple fmt: skip on string literals
+a = (
+    "this should "  # fmt: skip
+    "be fine"
+)
+
+b = (
+    "this is "  # fmt: skip
+    "not working"  # fmt: skip
+)
+
+c = (
+    "and neither "  # fmt: skip
+    "is this "  # fmt: skip
+    "working"
+)
+
+d = (
+    "nor "
+    "is this "  # fmt: skip
+    "working"  # fmt: skip
+)
+
+e = (
+    "and this "  # fmt: skip
+    "is definitely "
+    "not working"  # fmt: skip
+)
+
+# Dictionary entries with fmt: skip (covers issue with long lines)
+hotkeys = {
+    "editor:swap-line-down": [
+        {"key": "ArrowDown", "modifiers": ["Alt", "Mod"]}
+    ],  # fmt: skip
+    "editor:swap-line-up": [
+        {"key": "ArrowUp", "modifiers": ["Alt", "Mod"]}
+    ],  # fmt: skip
+    "editor:toggle-source": [{"key": "S", "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+}
+```
+
+## Black Output
+
+```python
+# Multiple fmt: skip on string literals
+a = (
+    "this should "  # fmt: skip
+    "be fine"
+)
+
+b = (
+    "this is "  # fmt: skip
+    "not working"  # fmt: skip
+)
+
+c = (
+    "and neither "  # fmt: skip
+    "is this "  # fmt: skip
+    "working"
+)
+
+d = (
+    "nor "
+    "is this "  # fmt: skip
+    "working"  # fmt: skip
+)
+
+e = (
+    "and this "  # fmt: skip
+    "is definitely "
+    "not working"  # fmt: skip
+)
+
+# Dictionary entries with fmt: skip (covers issue with long lines)
+hotkeys = {
+    "editor:swap-line-down": [{"key": "ArrowDown", "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:swap-line-up":   [{"key": "ArrowUp",   "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+    "editor:toggle-source":  [{"key": "S",         "modifiers": ["Alt", "Mod"]}],  # fmt: skip
+}
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__pep_750.py.snap

@@ -0,0 +1,188 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+x = t"foo"
+x = t'foo {{ {2 + 2}bar {{ baz'
+
+x = t"foo {f'abc'} bar"
+
+x = t"""foo {{ a
+    foo {2 + 2}bar {{ baz
+
+    x = f"foo {{ {
+        2 + 2  # comment
+    }bar"
+
+    {{ baz
+
+    }} buzz
+
+    {print("abc" + "def"
+)}
+abc"""
+
+t'{(abc:=10)}'
+
+t'''This is a really long string, but just make sure that you reflow tstrings {
+    2+2:d
+}'''
+t'This is a really long string, but just make sure that you reflow tstrings correctly {2+2:d}'
+
+t"{     2      +     2    =    }"
+
+t'{
+X
+!r
+}'
+
+tr'\{{\}}'
+
+t'''
+    WITH {f'''
+    {1}_cte AS ()'''}
+'''
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -7,34 +7,32 @@
+     foo {2 + 2}bar {{ baz
+ 
+     x = f"foo {{ {
+-        2 + 2  # comment
+-    }bar"
++    2 + 2  # comment
++}bar"
+ 
+     {{ baz
+ 
+     }} buzz
+ 
+-    {print("abc" + "def"
+-)}
++    {print("abc" + "def")}
+ abc"""
+ 
+-t"{(abc:=10)}"
++t"{(abc := 10)}"
+ 
+ t"""This is a really long string, but just make sure that you reflow tstrings {
+-    2+2:d
++    2 + 2:d
+ }"""
+-t"This is a really long string, but just make sure that you reflow tstrings correctly {2+2:d}"
++t"This is a really long string, but just make sure that you reflow tstrings correctly {2 + 2:d}"
+ 
+ t"{     2      +     2    =    }"
+ 
+-t"{
+-X
+-!r
+-}"
++t"{X!r}"
+ 
+ rt"\{{\}}"
+ 
+ t"""
+-    WITH {f'''
+-    {1}_cte AS ()'''}
++    WITH {
++    f'''
++    {1}_cte AS ()'''
++}
+ """
+```
+
+## Ruff Output
+
+```python
+x = t"foo"
+x = t"foo {{ {2 + 2}bar {{ baz"
+
+x = t"foo {f'abc'} bar"
+
+x = t"""foo {{ a
+    foo {2 + 2}bar {{ baz
+
+    x = f"foo {{ {
+    2 + 2  # comment
+}bar"
+
+    {{ baz
+
+    }} buzz
+
+    {print("abc" + "def")}
+abc"""
+
+t"{(abc := 10)}"
+
+t"""This is a really long string, but just make sure that you reflow tstrings {
+    2 + 2:d
+}"""
+t"This is a really long string, but just make sure that you reflow tstrings correctly {2 + 2:d}"
+
+t"{     2      +     2    =    }"
+
+t"{X!r}"
+
+rt"\{{\}}"
+
+t"""
+    WITH {
+    f'''
+    {1}_cte AS ()'''
+}
+"""
+```
+
+## Black Output
+
+```python
+x = t"foo"
+x = t"foo {{ {2 + 2}bar {{ baz"
+
+x = t"foo {f'abc'} bar"
+
+x = t"""foo {{ a
+    foo {2 + 2}bar {{ baz
+
+    x = f"foo {{ {
+        2 + 2  # comment
+    }bar"
+
+    {{ baz
+
+    }} buzz
+
+    {print("abc" + "def"
+)}
+abc"""
+
+t"{(abc:=10)}"
+
+t"""This is a really long string, but just make sure that you reflow tstrings {
+    2+2:d
+}"""
+t"This is a really long string, but just make sure that you reflow tstrings correctly {2+2:d}"
+
+t"{     2      +     2    =    }"
+
+t"{
+X
+!r
+}"
+
+rt"\{{\}}"
+
+t"""
+    WITH {f'''
+    {1}_cte AS ()'''}
+"""
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__preview_fmtpass_imports.py.snap

@@ -0,0 +1,90 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+# Regression test for https://github.com/psf/black/issues/3438
+
+import ast
+import collections  # fmt: skip
+import dataclasses
+# fmt: off
+import os
+# fmt: on
+import pathlib
+
+import re  # fmt: skip
+import secrets
+
+# fmt: off
+import sys
+# fmt: on
+
+import tempfile
+import zoneinfo
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -3,6 +3,7 @@
+ import ast
+ import collections  # fmt: skip
+ import dataclasses
++
+ # fmt: off
+ import os
+ # fmt: on
+```
+
+## Ruff Output
+
+```python
+# Regression test for https://github.com/psf/black/issues/3438
+
+import ast
+import collections  # fmt: skip
+import dataclasses
+
+# fmt: off
+import os
+# fmt: on
+import pathlib
+
+import re  # fmt: skip
+import secrets
+
+# fmt: off
+import sys
+# fmt: on
+
+import tempfile
+import zoneinfo
+```
+
+## Black Output
+
+```python
+# Regression test for https://github.com/psf/black/issues/3438
+
+import ast
+import collections  # fmt: skip
+import dataclasses
+# fmt: off
+import os
+# fmt: on
+import pathlib
+
+import re  # fmt: skip
+import secrets
+
+# fmt: off
+import sys
+# fmt: on
+
+import tempfile
+import zoneinfo
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__preview_multiline_strings.py.snap

@@ -1,6 +1,5 @@
 ---
 source: crates/ruff_python_formatter/tests/fixtures.rs
-input_file: crates/ruff_python_formatter/resources/test/fixtures/black/cases/preview_multiline_strings.py
 ---
 ## Input
 
@@ -163,24 +162,6 @@ Please use `--build-option` instead,
 `--global-option` is reserved to flags like `--verbose` or `--quiet`.
 """
 
-this_will_become_one_line = (
-    "a"
-    "b"
-    "c"
-)
-
-this_will_stay_on_three_lines = (
-    "a"  # comment
-    "b"
-    "c"
-)
-
-this_will_also_become_one_line = (  # comment
-    "a"
-    "b"
-    "c"
-)
-
 assert some_var == expected_result, """
 test
 """
@@ -421,18 +402,7 @@ a = b if """
  [
      """cow
  moos""",
-@@ -206,7 +245,9 @@
-     "c"
- )
- 
--this_will_also_become_one_line = "abc"  # comment
-+this_will_also_become_one_line = (  # comment
-+    "abc"
-+)
- 
- assert some_var == expected_result, """
- test
-@@ -224,10 +265,8 @@
+@@ -214,10 +253,8 @@
                  """Sxxxxxxx xxxxxxxx, xxxxxxx xx xxxxxxxxx
                  xxxxxxxxxxxxx xxxxxxx xxxxxxxxx xxx-xxxxxxxxxx xxxxxx xx xxx-xxxxxx"""
              ),
@@ -445,7 +415,7 @@ a = b if """
          },
      }
  
-@@ -246,14 +285,12 @@
+@@ -236,14 +273,12 @@
  a
  a"""
      ),
@@ -706,18 +676,6 @@ Please use `--build-option` instead,
 `--global-option` is reserved to flags like `--verbose` or `--quiet`.
 """
 
-this_will_become_one_line = "abc"
-
-this_will_stay_on_three_lines = (
-    "a"  # comment
-    "b"
-    "c"
-)
-
-this_will_also_become_one_line = (  # comment
-    "abc"
-)
-
 assert some_var == expected_result, """
 test
 """
@@ -1028,16 +986,6 @@ Please use `--build-option` instead,
 `--global-option` is reserved to flags like `--verbose` or `--quiet`.
 """
 
-this_will_become_one_line = "abc"
-
-this_will_stay_on_three_lines = (
-    "a"  # comment
-    "b"
-    "c"
-)
-
-this_will_also_become_one_line = "abc"  # comment
-
 assert some_var == expected_result, """
 test
 """

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__preview_standardize_type_comments.py.snap

@@ -0,0 +1,67 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+def foo(
+    a, #type:int
+    b, #type: str
+    c, # type: List[int]
+    d, #  type:  Dict[int, str]
+    e, #       type:     ignore
+    f, # type : ignore
+    g, #  type : ignore
+):
+    pass
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -1,9 +1,9 @@
+ def foo(
+-    a,  # type: int
++    a,  # type:int
+     b,  # type: str
+     c,  # type: List[int]
+-    d,  # type: Dict[int, str]
+-    e,  # type: ignore
++    d,  #  type:  Dict[int, str]
++    e,  #       type:     ignore
+     f,  # type : ignore
+     g,  #  type : ignore
+ ):
+```
+
+## Ruff Output
+
+```python
+def foo(
+    a,  # type:int
+    b,  # type: str
+    c,  # type: List[int]
+    d,  #  type:  Dict[int, str]
+    e,  #       type:     ignore
+    f,  # type : ignore
+    g,  #  type : ignore
+):
+    pass
+```
+
+## Black Output
+
+```python
+def foo(
+    a,  # type: int
+    b,  # type: str
+    c,  # type: List[int]
+    d,  # type: Dict[int, str]
+    e,  # type: ignore
+    f,  # type : ignore
+    g,  #  type : ignore
+):
+    pass
+```

crates/ruff_python_formatter/tests/snapshots/black_compatibility@cases__remove_parens_from_lhs.py.snap

@@ -0,0 +1,85 @@
+---
+source: crates/ruff_python_formatter/tests/fixtures.rs
+---
+## Input
+
+```python
+# Remove unnecessary parentheses from LHS of assignments
+
+
+def a():
+    return [1, 2, 3]
+
+
+# Single variable with unnecessary parentheses
+(b) = a()[0]
+
+# Tuple unpacking with unnecessary parentheses
+(c, *_) = a()
+
+# These should not be changed - parentheses are necessary
+(d,) = a()  # single-element tuple
+e = (1 + 2) * 3  # RHS has precedence needs
+```
+
+## Black Differences
+
+```diff
+--- Black
++++ Ruff
+@@ -6,10 +6,10 @@
+ 
+ 
+ # Single variable with unnecessary parentheses
+-b = a()[0]
++(b) = a()[0]
+ 
+ # Tuple unpacking with unnecessary parentheses
+-c, *_ = a()
++(c, *_) = a()
+ 
+ # These should not be changed - parentheses are necessary
+ (d,) = a()  # single-element tuple
+```
+
+## Ruff Output
+
+```python
+# Remove unnecessary parentheses from LHS of assignments
+
+
+def a():
+    return [1, 2, 3]
+
+
+# Single variable with unnecessary parentheses
+(b) = a()[0]
+
+# Tuple unpacking with unnecessary parentheses
+(c, *_) = a()
+
+# These should not be changed - parentheses are necessary
+(d,) = a()  # single-element tuple
+e = (1 + 2) * 3  # RHS has precedence needs
+```
+
+## Black Output
+
+```python
+# Remove unnecessary parentheses from LHS of assignments
+
+
+def a():
+    return [1, 2, 3]
+
+
+# Single variable with unnecessary parentheses
+b = a()[0]
+
+# Tuple unpacking with unnecessary parentheses
+c, *_ = a()
+
+# These should not be changed - parentheses are necessary
+(d,) = a()  # single-element tuple
+e = (1 + 2) * 3  # RHS has precedence needs
+```

crates/ty/docs/cli.md

@@ -37,7 +37,8 @@ ty check [OPTIONS] [PATH]...
 
 <h3 class="cli-reference">Options</h3>
 
-<dl class="cli-reference"><dt id="ty-check--color"><a href="#ty-check--color"><code>--color</code></a> <i>when</i></dt><dd><p>Control when colored output is used</p>
+<dl class="cli-reference"><dt id="ty-check--add-ignore"><a href="#ty-check--add-ignore"><code>--add-ignore</code></a></dt><dd><p>Adds <code>ty: ignore</code> comments to suppress all rule diagnostics</p>
+</dd><dt id="ty-check--color"><a href="#ty-check--color"><code>--color</code></a> <i>when</i></dt><dd><p>Control when colored output is used</p>
 <p>Possible values:</p>
 <ul>
 <li><code>auto</code>:  Display colors if the output goes to an interactive terminal</li>

crates/ty/docs/rules.md

@@ -8,7 +8,7 @@
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.20">0.0.1-alpha.20</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20ambiguous-protocol-member" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L538" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L540" target="_blank">View source</a>
 </small>
 
 
@@ -80,7 +80,7 @@ def test(): -> "int":
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20call-non-callable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L137" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L139" target="_blank">View source</a>
 </small>
 
 
@@ -104,7 +104,7 @@ Calling a non-callable object will raise a `TypeError` at runtime.
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.7">0.0.7</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20call-top-callable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L155" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L157" target="_blank">View source</a>
 </small>
 
 
@@ -135,7 +135,7 @@ def f(x: object):
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-argument-forms" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L206" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L208" target="_blank">View source</a>
 </small>
 
 
@@ -167,7 +167,7 @@ f(int)  # error
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-declarations" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L232" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L234" target="_blank">View source</a>
 </small>
 
 
@@ -198,7 +198,7 @@ a = 1
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20conflicting-metaclass" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L257" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L259" target="_blank">View source</a>
 </small>
 
 
@@ -230,7 +230,7 @@ class C(A, B): ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20cyclic-class-definition" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L283" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L285" target="_blank">View source</a>
 </small>
 
 
@@ -262,7 +262,7 @@ class B(A): ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Preview (since <a href="https://github.com/astral-sh/ty/releases/tag/1.0.0">1.0.0</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20cyclic-type-alias-definition" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L309" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L311" target="_blank">View source</a>
 </small>
 
 
@@ -290,7 +290,7 @@ type B = A
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.16">0.0.1-alpha.16</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20deprecated" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L353" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L355" target="_blank">View source</a>
 </small>
 
 
@@ -317,7 +317,7 @@ old_func()  # emits [deprecated] diagnostic
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'ignore'."><code>ignore</code></a> ·
 Preview (since <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20division-by-zero" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L331" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L333" target="_blank">View source</a>
 </small>
 
 
@@ -346,7 +346,7 @@ false positives it can produce.
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20duplicate-base" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L374" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L376" target="_blank">View source</a>
 </small>
 
 
@@ -373,7 +373,7 @@ class B(A, A): ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.12">0.0.1-alpha.12</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20duplicate-kw-only" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L395" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L397" target="_blank">View source</a>
 </small>
 
 
@@ -529,7 +529,7 @@ def test(): -> "Literal[5]":
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20inconsistent-mro" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L621" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L623" target="_blank">View source</a>
 </small>
 
 
@@ -559,7 +559,7 @@ class C(A, B): ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20index-out-of-bounds" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L645" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L647" target="_blank">View source</a>
 </small>
 
 
@@ -585,7 +585,7 @@ t[3]  # IndexError: tuple index out of range
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.12">0.0.1-alpha.12</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20instance-layout-conflict" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L427" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L429" target="_blank">View source</a>
 </small>
 
 
@@ -674,7 +674,7 @@ an atypical memory layout.
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-argument-type" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L699" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L701" target="_blank">View source</a>
 </small>
 
 
@@ -701,7 +701,7 @@ func("foo")  # error: [invalid-argument-type]
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-assignment" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L739" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L741" target="_blank">View source</a>
 </small>
 
 
@@ -729,7 +729,7 @@ a: int = ''
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-attribute-access" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2042" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2044" target="_blank">View source</a>
 </small>
 
 
@@ -763,7 +763,7 @@ C.instance_var = 3  # error: Cannot assign to instance variable
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.19">0.0.1-alpha.19</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-await" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L761" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L763" target="_blank">View source</a>
 </small>
 
 
@@ -799,7 +799,7 @@ asyncio.run(main())
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-base" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L791" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L793" target="_blank">View source</a>
 </small>
 
 
@@ -823,7 +823,7 @@ class A(42): ...  # error: [invalid-base]
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-context-manager" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L842" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L844" target="_blank">View source</a>
 </small>
 
 
@@ -850,7 +850,7 @@ with 1:
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-declaration" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L863" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L865" target="_blank">View source</a>
 </small>
 
 
@@ -879,7 +879,7 @@ a: str
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-exception-caught" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L886" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L888" target="_blank">View source</a>
 </small>
 
 
@@ -923,7 +923,7 @@ except ZeroDivisionError:
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.28">0.0.1-alpha.28</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-explicit-override" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1712" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1714" target="_blank">View source</a>
 </small>
 
 
@@ -965,7 +965,7 @@ class D(A):
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.35">0.0.1-alpha.35</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-frozen-dataclass-subclass" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2268" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2295" target="_blank">View source</a>
 </small>
 
 
@@ -1009,7 +1009,7 @@ class NonFrozenChild(FrozenBase):  # Error raised here
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-generic-class" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L922" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L924" target="_blank">View source</a>
 </small>
 
 
@@ -1077,7 +1077,7 @@ a = 20 / 0  # type: ignore
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.17">0.0.1-alpha.17</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-key" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L666" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L668" target="_blank">View source</a>
 </small>
 
 
@@ -1116,7 +1116,7 @@ carol = Person(name="Carol", age=25)  # typo!
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-legacy-type-variable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L953" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L955" target="_blank">View source</a>
 </small>
 
 
@@ -1151,7 +1151,7 @@ def f(t: TypeVar("U")): ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-metaclass" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1050" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1052" target="_blank">View source</a>
 </small>
 
 
@@ -1185,7 +1185,7 @@ class B(metaclass=f): ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.20">0.0.1-alpha.20</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-method-override" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2170" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2197" target="_blank">View source</a>
 </small>
 
 
@@ -1292,7 +1292,7 @@ Correct use of `@override` is enforced by ty's `invalid-explicit-override` rule.
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.19">0.0.1-alpha.19</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-named-tuple" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L573" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L575" target="_blank">View source</a>
 </small>
 
 
@@ -1346,7 +1346,7 @@ AttributeError: Cannot overwrite NamedTuple attribute _asdict
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Preview (since <a href="https://github.com/astral-sh/ty/releases/tag/1.0.0">1.0.0</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-newtype" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1026" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1028" target="_blank">View source</a>
 </small>
 
 
@@ -1376,7 +1376,7 @@ Baz = NewType("Baz", int | str)  # error: invalid base for `typing.NewType`
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-overload" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1077" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1079" target="_blank">View source</a>
 </small>
 
 
@@ -1426,7 +1426,7 @@ def foo(x: int) -> int: ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-parameter-default" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1176" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1178" target="_blank">View source</a>
 </small>
 
 
@@ -1452,7 +1452,7 @@ def f(a: int = ''): ...
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-paramspec" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L981" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L983" target="_blank">View source</a>
 </small>
 
 
@@ -1483,7 +1483,7 @@ P2 = ParamSpec("S2")  # error: ParamSpec name must match the variable it's assig
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-protocol" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L509" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L511" target="_blank">View source</a>
 </small>
 
 
@@ -1517,7 +1517,7 @@ TypeError: Protocols can only inherit from other protocols, got <class 'int'>
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-raise" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1196" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1198" target="_blank">View source</a>
 </small>
 
 
@@ -1566,7 +1566,7 @@ def g():
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-return-type" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L720" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L722" target="_blank">View source</a>
 </small>
 
 
@@ -1591,7 +1591,7 @@ def func() -> int:
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-super-argument" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1239" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1241" target="_blank">View source</a>
 </small>
 
 
@@ -1681,13 +1681,59 @@ class C: ...
 - [Typing spec: The meaning of annotations](https://typing.python.org/en/latest/spec/annotations.html#the-meaning-of-annotations)
 - [Typing spec: String annotations](https://typing.python.org/en/latest/spec/annotations.html#string-annotations)
 
+## `invalid-total-ordering`
+
+<small>
+Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
+Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.10">0.0.10</a> ·
+<a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-total-ordering" target="_blank">Related issues</a> ·
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2333" target="_blank">View source</a>
+</small>
+
+
+**What it does**
+
+Checks for classes decorated with `@functools.total_ordering` that don't
+define any ordering method (`__lt__`, `__le__`, `__gt__`, or `__ge__`).
+
+**Why is this bad?**
+
+The `@total_ordering` decorator requires the class to define at least one
+ordering method. If none is defined, Python raises a `ValueError` at runtime.
+
+**Example**
+
+
+```python
+from functools import total_ordering
+
+@total_ordering
+class MyClass:  # Error: no ordering method defined
+    def __eq__(self, other: object) -> bool:
+        return True
+```
+
+Use instead:
+
+```python
+from functools import total_ordering
+
+@total_ordering
+class MyClass:
+    def __eq__(self, other: object) -> bool:
+        return True
+
+    def __lt__(self, other: "MyClass") -> bool:
+        return True
+```
+
 ## `invalid-type-alias-type`
 
 <small>
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.6">0.0.1-alpha.6</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-alias-type" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1005" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1007" target="_blank">View source</a>
 </small>
 
 
@@ -1714,7 +1760,7 @@ NewAlias = TypeAliasType(get_name(), int)        # error: TypeAliasType name mus
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.29">0.0.1-alpha.29</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-arguments" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1471" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1473" target="_blank">View source</a>
 </small>
 
 
@@ -1761,7 +1807,7 @@ Bar[int]  # error: too few arguments
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-checking-constant" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1278" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1280" target="_blank">View source</a>
 </small>
 
 
@@ -1791,7 +1837,7 @@ TYPE_CHECKING = ''
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-form" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1302" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1304" target="_blank">View source</a>
 </small>
 
 
@@ -1821,7 +1867,7 @@ b: Annotated[int]  # `Annotated` expects at least two arguments
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.11">0.0.1-alpha.11</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-guard-call" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1354" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1356" target="_blank">View source</a>
 </small>
 
 
@@ -1855,7 +1901,7 @@ f(10)  # Error
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.11">0.0.1-alpha.11</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-guard-definition" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1326" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1328" target="_blank">View source</a>
 </small>
 
 
@@ -1889,7 +1935,7 @@ class C:
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-type-variable-constraints" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1382" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1384" target="_blank">View source</a>
 </small>
 
 
@@ -1918,13 +1964,44 @@ T = TypeVar('T', bound=str)  # valid bound TypeVar
 
 [type variables]: https://docs.python.org/3/library/typing.html#typing.TypeVar
 
+## `invalid-typed-dict-statement`
+
+<small>
+Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
+Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.9">0.0.9</a> ·
+<a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20invalid-typed-dict-statement" target="_blank">Related issues</a> ·
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2172" target="_blank">View source</a>
+</small>
+
+
+**What it does**
+
+Detects statements other than annotated declarations in `TypedDict` class bodies.
+
+**Why is this bad?**
+
+`TypedDict` class bodies aren't allowed to contain any other types of statements. For
+example, method definitions and field values aren't allowed. None of these will be
+available on "instances of the `TypedDict`" at runtime (as `dict` is the runtime class of
+all "`TypedDict` instances").
+
+**Example**
+
+```python
+from typing import TypedDict
+
+class Foo(TypedDict):
+    def bar(self):  # error: [invalid-typed-dict-statement]
+        pass
+```
+
 ## `missing-argument`
 
 <small>
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20missing-argument" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1411" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1413" target="_blank">View source</a>
 </small>
 
 
@@ -1949,7 +2026,7 @@ func()  # TypeError: func() missing 1 required positional argument: 'x'
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.20">0.0.1-alpha.20</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20missing-typed-dict-key" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2143" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2145" target="_blank">View source</a>
 </small>
 
 
@@ -1982,7 +2059,7 @@ alice["age"]  # KeyError
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20no-matching-overload" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1430" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1432" target="_blank">View source</a>
 </small>
 
 
@@ -2011,7 +2088,7 @@ func("string")  # error: [no-matching-overload]
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20not-iterable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1512" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1514" target="_blank">View source</a>
 </small>
 
 
@@ -2037,7 +2114,7 @@ for i in 34:  # TypeError: 'int' object is not iterable
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20not-subscriptable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1453" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1455" target="_blank">View source</a>
 </small>
 
 
@@ -2061,7 +2138,7 @@ Subscripting an object that does not support it will raise a `TypeError` at runt
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.29">0.0.1-alpha.29</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20override-of-final-method" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1685" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1687" target="_blank">View source</a>
 </small>
 
 
@@ -2094,7 +2171,7 @@ class B(A):
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20parameter-already-assigned" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1563" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1565" target="_blank">View source</a>
 </small>
 
 
@@ -2121,7 +2198,7 @@ f(1, x=2)  # Error raised here
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20positional-only-parameter-as-kwarg" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1896" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1898" target="_blank">View source</a>
 </small>
 
 
@@ -2148,7 +2225,7 @@ f(x=1)  # Error raised here
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-missing-attribute" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1584" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1586" target="_blank">View source</a>
 </small>
 
 
@@ -2176,7 +2253,7 @@ A.c  # AttributeError: type object 'A' has no attribute 'c'
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-missing-implicit-call" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L180" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L182" target="_blank">View source</a>
 </small>
 
 
@@ -2208,7 +2285,7 @@ A()[0]  # TypeError: 'A' object is not subscriptable
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'ignore'."><code>ignore</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-missing-import" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1606" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1608" target="_blank">View source</a>
 </small>
 
 
@@ -2245,7 +2322,7 @@ from module import a  # ImportError: cannot import name 'a' from 'module'
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'ignore'."><code>ignore</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20possibly-unresolved-reference" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1636" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1638" target="_blank">View source</a>
 </small>
 
 
@@ -2309,7 +2386,7 @@ def test(): -> "int":
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20redundant-cast" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2070" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2072" target="_blank">View source</a>
 </small>
 
 
@@ -2336,7 +2413,7 @@ cast(int, f())  # Redundant
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20static-assert-error" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2018" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2020" target="_blank">View source</a>
 </small>
 
 
@@ -2366,7 +2443,7 @@ static_assert(int(2.0 * 3.0) == 6)  # error: does not have a statically known tr
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20subclass-of-final-class" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1662" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1664" target="_blank">View source</a>
 </small>
 
 
@@ -2395,7 +2472,7 @@ class B(A): ...  # Error raised here
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Preview (since <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.30">0.0.1-alpha.30</a>) ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20super-call-in-named-tuple-method" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1830" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1832" target="_blank">View source</a>
 </small>
 
 
@@ -2429,7 +2506,7 @@ class F(NamedTuple):
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20too-many-positional-arguments" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1770" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1772" target="_blank">View source</a>
 </small>
 
 
@@ -2456,7 +2533,7 @@ f("foo")  # Error raised here
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20type-assertion-failure" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1748" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1750" target="_blank">View source</a>
 </small>
 
 
@@ -2484,7 +2561,7 @@ def _(x: int):
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unavailable-implicit-super-arguments" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1791" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1793" target="_blank">View source</a>
 </small>
 
 
@@ -2530,7 +2607,7 @@ class A:
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20undefined-reveal" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1857" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1859" target="_blank">View source</a>
 </small>
 
 
@@ -2554,7 +2631,7 @@ reveal_type(1)  # NameError: name 'reveal_type' is not defined
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unknown-argument" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1875" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1877" target="_blank">View source</a>
 </small>
 
 
@@ -2581,7 +2658,7 @@ f(x=1, y=2)  # Error raised here
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-attribute" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1917" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1919" target="_blank">View source</a>
 </small>
 
 
@@ -2609,7 +2686,7 @@ A().foo  # AttributeError: 'A' object has no attribute 'foo'
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.15">0.0.1-alpha.15</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-global" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2091" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2093" target="_blank">View source</a>
 </small>
 
 
@@ -2667,7 +2744,7 @@ def g():
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-import" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1939" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1941" target="_blank">View source</a>
 </small>
 
 
@@ -2692,7 +2769,7 @@ import foo  # ModuleNotFoundError: No module named 'foo'
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unresolved-reference" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1958" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1960" target="_blank">View source</a>
 </small>
 
 
@@ -2717,7 +2794,7 @@ print(x)  # NameError: name 'x' is not defined
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.7">0.0.1-alpha.7</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-base" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L809" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L811" target="_blank">View source</a>
 </small>
 
 
@@ -2756,7 +2833,7 @@ class D(C): ...  # error: [unsupported-base]
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-bool-conversion" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1532" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1534" target="_blank">View source</a>
 </small>
 
 
@@ -2793,7 +2870,7 @@ b1 < b2 < b1  # exception raised here
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20unsupported-operator" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1977" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1979" target="_blank">View source</a>
 </small>
 
 
@@ -2852,7 +2929,7 @@ a = 20 / 2
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'warn'."><code>warn</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.22">0.0.1-alpha.22</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20useless-overload-body" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1120" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1122" target="_blank">View source</a>
 </small>
 
 
@@ -2915,7 +2992,7 @@ def foo(x: int | str) -> int | str:
 Default level: <a href="../../rules#rule-levels" title="This lint has a default level of 'error'."><code>error</code></a> ·
 Added in <a href="https://github.com/astral-sh/ty/releases/tag/0.0.1-alpha.1">0.0.1-alpha.1</a> ·
 <a href="https://github.com/astral-sh/ty/issues?q=sort%3Aupdated-desc%20is%3Aissue%20is%3Aopen%20zero-stepsize-in-slice" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1999" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2001" target="_blank">View source</a>
 </small>
 
 

crates/ty/src/args.rs

@@ -54,6 +54,10 @@ pub(crate) struct CheckCommand {
     )]
     pub paths: Vec<SystemPathBuf>,
 
+    /// Adds `ty: ignore` comments to suppress all rule diagnostics.
+    #[arg(long)]
+    pub(crate) add_ignore: bool,
+
     /// Run the command within the given project directory.
     ///
     /// All `pyproject.toml` files will be discovered by walking up the directory tree from the given project directory,

crates/ty/src/lib.rs

@@ -4,37 +4,36 @@ mod printer;
 mod python_version;
 mod version;
 
-pub use args::Cli;
-use ty_project::metadata::settings::TerminalSettings;
-use ty_static::EnvVars;
-
 use std::fmt::Write;
 use std::process::{ExitCode, Termination};
 use std::sync::Mutex;
 
 use anyhow::Result;
-
-use crate::args::{CheckCommand, Command, TerminalColor};
-use crate::logging::{VerbosityLevel, setup_tracing};
-use crate::printer::Printer;
 use anyhow::{Context, anyhow};
 use clap::{CommandFactory, Parser};
 use colored::Colorize;
 use crossbeam::channel as crossbeam_channel;
 use rayon::ThreadPoolBuilder;
-use ruff_db::cancellation::{CancellationToken, CancellationTokenSource};
+use ruff_db::cancellation::{Canceled, CancellationToken, CancellationTokenSource};
 use ruff_db::diagnostic::{
     Diagnostic, DiagnosticId, DisplayDiagnosticConfig, DisplayDiagnostics, Severity,
 };
 use ruff_db::files::File;
-use ruff_db::max_parallelism;
 use ruff_db::system::{OsSystem, SystemPath, SystemPathBuf};
+use ruff_db::{STACK_SIZE, max_parallelism};
 use salsa::Database;
 use ty_project::metadata::options::ProjectOptionsOverrides;
+use ty_project::metadata::settings::TerminalSettings;
 use ty_project::watch::ProjectWatcher;
-use ty_project::{CollectReporter, Db, watch};
+use ty_project::{CollectReporter, Db, suppress_all_diagnostics, watch};
 use ty_project::{ProjectDatabase, ProjectMetadata};
 use ty_server::run_server;
+use ty_static::EnvVars;
+
+use crate::args::{CheckCommand, Command, TerminalColor};
+use crate::logging::{VerbosityLevel, setup_tracing};
+use crate::printer::Printer;
+pub use args::Cli;
 
 pub fn run() -> anyhow::Result<ExitStatus> {
     setup_rayon();
@@ -112,6 +111,12 @@ fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
         .map(|path| SystemPath::absolute(path, &cwd))
         .collect();
 
+    let mode = if args.add_ignore {
+        MainLoopMode::AddIgnore
+    } else {
+        MainLoopMode::Check
+    };
+
     let system = OsSystem::new(&cwd);
     let watch = args.watch;
     let exit_zero = args.exit_zero;
@@ -144,7 +149,7 @@ fn run_check(args: CheckCommand) -> anyhow::Result<ExitStatus> {
     }
 
     let (main_loop, main_loop_cancellation_token) =
-        MainLoop::new(project_options_overrides, printer);
+        MainLoop::new(mode, project_options_overrides, printer);
 
     // Listen to Ctrl+C and abort the watch mode.
     let main_loop_cancellation_token = Mutex::new(Some(main_loop_cancellation_token));
@@ -215,6 +220,8 @@ impl Termination for ExitStatus {
 }
 
 struct MainLoop {
+    mode: MainLoopMode,
+
     /// Sender that can be used to send messages to the main loop.
     sender: crossbeam_channel::Sender<MainLoopMessage>,
 
@@ -237,6 +244,7 @@ struct MainLoop {
 
 impl MainLoop {
     fn new(
+        mode: MainLoopMode,
         project_options_overrides: ProjectOptionsOverrides,
         printer: Printer,
     ) -> (Self, MainLoopCancellationToken) {
@@ -247,6 +255,7 @@ impl MainLoop {
 
         (
             Self {
+                mode,
                 sender: sender.clone(),
                 receiver,
                 watcher: None,
@@ -325,80 +334,78 @@ impl MainLoop {
                     result,
                     revision: check_revision,
                 } => {
-                    let terminal_settings = db.project().settings(db).terminal();
-                    let display_config = DisplayDiagnosticConfig::default()
-                        .format(terminal_settings.output_format.into())
-                        .color(colored::control::SHOULD_COLORIZE.should_colorize())
-                        .with_cancellation_token(Some(self.cancellation_token.clone()))
-                        .show_fix_diff(true);
-
-                    if check_revision == revision {
-                        if db.project().files(db).is_empty() {
-                            tracing::warn!("No python files found under the given path(s)");
-                        }
-
-                        // TODO: We should have an official flag to silence workspace diagnostics.
-                        if std::env::var("TY_MEMORY_REPORT").as_deref() == Ok("mypy_primer") {
-                            return Ok(ExitStatus::Success);
-                        }
-
-                        let is_human_readable = terminal_settings.output_format.is_human_readable();
-
-                        if result.is_empty() {
-                            if is_human_readable {
-                                writeln!(
-                                    self.printer.stream_for_success_summary(),
-                                    "{}",
-                                    "All checks passed!".green().bold()
-                                )?;
-                            }
-
-                            if self.watcher.is_none() {
-                                return Ok(ExitStatus::Success);
-                            }
-                        } else {
-                            let diagnostics_count = result.len();
-
-                            let mut stdout = self.printer.stream_for_details().lock();
-                            let exit_status =
-                                exit_status_from_diagnostics(&result, terminal_settings);
-
-                            // Only render diagnostics if they're going to be displayed, since doing
-                            // so is expensive.
-                            if stdout.is_enabled() {
-                                write!(
-                                    stdout,
-                                    "{}",
-                                    DisplayDiagnostics::new(db, &display_config, &result)
-                                )?;
-                            }
-
-                            if !self.cancellation_token.is_cancelled() {
-                                if is_human_readable {
-                                    writeln!(
-                                        self.printer.stream_for_failure_summary(),
-                                        "Found {} diagnostic{}",
-                                        diagnostics_count,
-                                        if diagnostics_count > 1 { "s" } else { "" }
-                                    )?;
-                                }
-
-                                if exit_status.is_internal_error() {
-                                    tracing::warn!(
-                                        "A fatal error occurred while checking some files. Not all project files were analyzed. See the diagnostics list above for details."
-                                    );
-                                }
-                            }
-
-                            if self.watcher.is_none() {
-                                return Ok(exit_status);
-                            }
-                        }
-                    } else {
+                    if check_revision != revision {
                         tracing::debug!(
                             "Discarding check result for outdated revision: current: {revision}, result revision: {check_revision}"
                         );
+                        continue;
                     }
+
+                    if db.project().files(db).is_empty() {
+                        tracing::warn!("No python files found under the given path(s)");
+                    }
+
+                    let result = match self.mode {
+                        MainLoopMode::Check => {
+                            // TODO: We should have an official flag to silence workspace diagnostics.
+                            if std::env::var("TY_MEMORY_REPORT").as_deref() == Ok("mypy_primer") {
+                                return Ok(ExitStatus::Success);
+                            }
+
+                            self.write_diagnostics(db, &result)?;
+
+                            if self.cancellation_token.is_cancelled() {
+                                Err(Canceled)
+                            } else {
+                                Ok(result)
+                            }
+                        }
+                        MainLoopMode::AddIgnore => {
+                            if let Ok(result) =
+                                suppress_all_diagnostics(db, result, &self.cancellation_token)
+                            {
+                                self.write_diagnostics(db, &result.diagnostics)?;
+
+                                let terminal_settings = db.project().settings(db).terminal();
+                                let is_human_readable =
+                                    terminal_settings.output_format.is_human_readable();
+
+                                if is_human_readable {
+                                    writeln!(
+                                        self.printer.stream_for_failure_summary(),
+                                        "Added {} ignore comment{}",
+                                        result.count,
+                                        if result.count > 1 { "s" } else { "" }
+                                    )?;
+                                }
+
+                                Ok(result.diagnostics)
+                            } else {
+                                Err(Canceled)
+                            }
+                        }
+                    };
+
+                    let exit_status = match result.as_deref() {
+                        Ok([]) => ExitStatus::Success,
+                        Ok(diagnostics) => {
+                            let terminal_settings = db.project().settings(db).terminal();
+                            exit_status_from_diagnostics(diagnostics, terminal_settings)
+                        }
+                        Err(Canceled) => ExitStatus::Success,
+                    };
+
+                    if exit_status.is_internal_error() {
+                        tracing::warn!(
+                            "A fatal error occurred while checking some files. Not all project files were analyzed. See the diagnostics list above for details."
+                        );
+                    }
+
+                    if self.watcher.is_some() {
+                        continue;
+                    }
+
+                    return Ok(exit_status);
                 }
 
                 MainLoopMessage::ApplyChanges(changes) => {
@@ -425,6 +432,65 @@ impl MainLoop {
 
         Ok(ExitStatus::Success)
     }
+
+    fn write_diagnostics(
+        &self,
+        db: &ProjectDatabase,
+        diagnostics: &[Diagnostic],
+    ) -> anyhow::Result<()> {
+        let terminal_settings = db.project().settings(db).terminal();
+        let is_human_readable = terminal_settings.output_format.is_human_readable();
+
+        match diagnostics {
+            [] => {
+                if is_human_readable {
+                    writeln!(
+                        self.printer.stream_for_success_summary(),
+                        "{}",
+                        "All checks passed!".green().bold()
+                    )?;
+                }
+            }
+            diagnostics => {
+                let diagnostics_count = diagnostics.len();
+
+                let mut stdout = self.printer.stream_for_details().lock();
+
+                // Only render diagnostics if they're going to be displayed, since doing
+                // so is expensive.
+                if stdout.is_enabled() {
+                    let display_config = DisplayDiagnosticConfig::default()
+                        .format(terminal_settings.output_format.into())
+                        .color(colored::control::SHOULD_COLORIZE.should_colorize())
+                        .with_cancellation_token(Some(self.cancellation_token.clone()))
+                        .show_fix_diff(true);
+
+                    write!(
+                        stdout,
+                        "{}",
+                        DisplayDiagnostics::new(db, &display_config, diagnostics)
+                    )?;
+                }
+
+                if !self.cancellation_token.is_cancelled() && is_human_readable {
+                    writeln!(
+                        self.printer.stream_for_failure_summary(),
+                        "Found {} diagnostic{}",
+                        diagnostics_count,
+                        if diagnostics_count > 1 { "s" } else { "" }
+                    )?;
+                }
+            }
+        }
+
+        Ok(())
+    }
+}
+
+#[derive(Copy, Clone, Debug)]
+enum MainLoopMode {
+    Check,
+    AddIgnore,
 }
 
 fn exit_status_from_diagnostics(
@@ -559,12 +625,7 @@ fn set_colored_override(color: Option<TerminalColor>) {
 fn setup_rayon() {
     ThreadPoolBuilder::default()
         .num_threads(max_parallelism().get())
-        // Use a reasonably large stack size to avoid running into stack overflows too easily. The
-        // size was chosen in such a way as to still be able to handle large expressions involving
-        // binary operators (x + x + … + x) both during the AST walk in semantic index building as
-        // well as during type checking. Using this stack size, we can handle handle expressions
-        // that are several times larger than the corresponding limits in existing type checkers.
-        .stack_size(16 * 1024 * 1024)
+        .stack_size(STACK_SIZE)
         .build_global()
         .unwrap();
 }

crates/ty/tests/cli/file_selection.rs

@@ -160,6 +160,65 @@ fn configuration_include() -> anyhow::Result<()> {
     Ok(())
 }
 
+/// Files without extensions can be included by adding a literal glob to `include` that matches
+/// the path exactly. A literal glob is a glob without any meta characters.
+#[test]
+fn configuration_include_no_extension() -> anyhow::Result<()> {
+    let case = CliTest::with_files([(
+        "src/main",
+        r#"
+            print(undefined_var)  # error: unresolved-reference
+            "#,
+    )])?;
+
+    // By default, `src/main` is excluded because the file has no supported extension.
+    case.write_file(
+        "ty.toml",
+        r#"
+        [src]
+        include = ["src"]
+        "#,
+    )?;
+
+    assert_cmd_snapshot!(case.command(), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    All checks passed!
+
+    ----- stderr -----
+    WARN No python files found under the given path(s)
+    ");
+
+    // The file can be included by adding an exactly matching pattern
+    case.write_file(
+        "ty.toml",
+        r#"
+        [src]
+        include = ["src", "src/main"]
+        "#,
+    )?;
+
+    assert_cmd_snapshot!(case.command(), @r"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    error[unresolved-reference]: Name `undefined_var` used when not defined
+     --> src/main:2:7
+      |
+    2 | print(undefined_var)  # error: unresolved-reference
+      |       ^^^^^^^^^^^^^
+      |
+    info: rule `unresolved-reference` is enabled by default
+
+    Found 1 diagnostic
+
+    ----- stderr -----
+    ");
+
+    Ok(())
+}
+
 /// Test configuration file exclude functionality
 #[test]
 fn configuration_exclude() -> anyhow::Result<()> {

crates/ty/tests/cli/fixes.rs

@@ -0,0 +1,114 @@
+use insta_cmd::assert_cmd_snapshot;
+
+use crate::CliTest;
+
+#[test]
+fn add_ignore() -> anyhow::Result<()> {
+    let case = CliTest::with_file(
+        "different_violations.py",
+        r#"
+            import sys
+
+            x = 1 + a
+
+            if sys.does_not_exist:
+                ...
+
+            def test(a, b): ...
+
+            test(x = 10, b = 12)
+            "#,
+    )?;
+
+    assert_cmd_snapshot!(case.command().arg("--add-ignore"), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    All checks passed!
+    Added 4 ignore comments
+
+    ----- stderr -----
+    ");
+
+    // There should be no diagnostics when running ty again
+    assert_cmd_snapshot!(case.command(), @r"
+    success: true
+    exit_code: 0
+    ----- stdout -----
+    All checks passed!
+
+    ----- stderr -----
+    ");
+
+    Ok(())
+}
+
+#[test]
+fn add_ignore_unfixable() -> anyhow::Result<()> {
+    let case = CliTest::with_files([
+        ("has_syntax_error.py", r"print(x  # [unresolved-reference]"),
+        (
+            "different_violations.py",
+            r#"
+            import sys
+
+            x = 1 + a
+
+            reveal_type(x)
+
+            if sys.does_not_exist:
+                ...
+            "#,
+        ),
+        (
+            "repeated_violations.py",
+            r#"
+            x = (
+                1 +
+                a * b
+            )
+
+            y = y  # ty: ignore[unresolved-reference]
+            "#,
+        ),
+    ])?;
+
+    assert_cmd_snapshot!(case.command().arg("--add-ignore").env("RUST_BACKTRACE", "1"), @r"
+    success: false
+    exit_code: 1
+    ----- stdout -----
+    info[revealed-type]: Revealed type
+     --> different_violations.py:6:13
+      |
+    4 | x = 1 + a  # ty:ignore[unresolved-reference]
+    5 |
+    6 | reveal_type(x)  # ty:ignore[undefined-reveal]
+      |             ^ `Unknown`
+    7 |
+    8 | if sys.does_not_exist:  # ty:ignore[unresolved-attribute]
+      |
+
+    error[unresolved-reference]: Name `x` used when not defined
+     --> has_syntax_error.py:1:7
+      |
+    1 | print(x  # [unresolved-reference]
+      |       ^
+      |
+    info: rule `unresolved-reference` is enabled by default
+
+    error[invalid-syntax]: unexpected EOF while parsing
+     --> has_syntax_error.py:1:34
+      |
+    1 | print(x  # [unresolved-reference]
+      |                                  ^
+      |
+
+    Found 3 diagnostics
+    Added 5 ignore comments
+
+    ----- stderr -----
+    WARN Skipping file `<temp_dir>/has_syntax_error.py` with syntax errors
+    ");
+
+    Ok(())
+}

crates/ty/tests/cli/main.rs

@@ -2,6 +2,7 @@ mod analysis_options;
 mod config_option;
 mod exit_code;
 mod file_selection;
+mod fixes;
 mod python_environment;
 mod rule_selection;
 

crates/ty_completion_eval/completion-evaluation-tasks.csv

@@ -3,6 +3,7 @@ auto-import-includes-modules,main.py,0,1
 auto-import-includes-modules,main.py,1,7
 auto-import-includes-modules,main.py,2,1
 auto-import-skips-current-module,main.py,0,1
+class-arg-completion,main.py,0,1
 fstring-completions,main.py,0,1
 higher-level-symbols-preferred,main.py,0,
 higher-level-symbols-preferred,main.py,1,1

crates/ty_completion_eval/truth/class-arg-completion/completion.toml

@@ -0,0 +1,2 @@
+[settings]
+auto-import = false

crates/ty_completion_eval/truth/class-arg-completion/main.py

@@ -0,0 +1 @@
+class Foo(m<CURSOR: metaclass>)

crates/ty_completion_eval/truth/class-arg-completion/pyproject.toml

@@ -0,0 +1,5 @@
+[project]
+name = "test"
+version = "0.1.0"
+requires-python = ">=3.13"
+dependencies = []

crates/ty_completion_eval/truth/class-arg-completion/uv.lock

@@ -0,0 +1,8 @@
+version = 1
+revision = 3
+requires-python = ">=3.13"
+
+[[package]]
+name = "test"
+version = "0.1.0"
+source = { virtual = "." }

crates/ty_ide/src/code_action.rs

@@ -5,8 +5,8 @@ use ruff_diagnostics::Edit;
 use ruff_python_ast::find_node::covering_node;
 use ruff_text_size::TextRange;
 use ty_project::Db;
-use ty_python_semantic::create_suppression_fix;
 use ty_python_semantic::lint::LintId;
+use ty_python_semantic::suppress_single;
 use ty_python_semantic::types::{UNDEFINED_REVEAL, UNRESOLVED_REFERENCE};
 
 /// A `QuickFix` Code Action
@@ -42,7 +42,7 @@ pub fn code_actions(
     // Suggest just suppressing the lint (always a valid option, but never ideal)
     actions.push(QuickFix {
         title: format!("Ignore '{}' for this line", lint_id.name()),
-        edits: create_suppression_fix(db, file, lint_id, diagnostic_range).into_edits(),
+        edits: suppress_single(db, file, lint_id, diagnostic_range).into_edits(),
         preferred: false,
     });
 
@@ -437,6 +437,38 @@ mod tests {
         "#);
     }
 
+    #[test]
+    fn add_ignore_line_continuation_empty_lines() {
+        let test = CodeActionTest::with_source(
+            r#"b = bbbbb \
+    [  ccc # test
+
+        + <START>ddd<END>  \
+
+    ] # test
+        "#,
+        );
+
+        assert_snapshot!(test.code_actions(&UNRESOLVED_REFERENCE), @r"
+        info[code-action]: Ignore 'unresolved-reference' for this line
+         --> main.py:4:11
+          |
+        2 |     [  ccc # test
+        3 |
+        4 |         + ddd  \
+          |           ^^^
+        5 |
+        6 |     ] # test
+          |
+        2 |     [  ccc # test
+        3 | 
+        4 |         + ddd  \
+          - 
+        5 +   # ty:ignore[unresolved-reference]
+        6 |     ] # test
+        ");
+    }
+
     #[test]
     fn undefined_reveal_type() {
         let test = CodeActionTest::with_source(

crates/ty_ide/src/completion.rs

@@ -193,15 +193,16 @@ impl<'db> Completions<'db> {
     /// when the completion context determines that the given suggestion
     /// is never valid.
     fn add_skip_query(&mut self, mut completion: Completion<'db>) -> bool {
-        // Tags completions with whether they are known to be usable in
-        // a `raise` context.
+        // Tags completions with context-specific if they are
+        // known to be usable in a `raise` context and we have
+        // determined a raisable type `raisable_ty`.
         //
         // It's possible that some completions are usable in a `raise`
         // but aren't marked here. That is, false negatives are
         // possible but false positives are not.
         if let Some(raisable_ty) = self.context.raisable_ty {
             if let Some(ty) = completion.ty {
-                completion.is_definitively_raisable = ty.is_assignable_to(self.db, raisable_ty);
+                completion.is_context_specific |= ty.is_assignable_to(self.db, raisable_ty);
             }
         }
         if self.context.exclude(self.db, &completion) {
@@ -285,13 +286,13 @@ pub struct Completion<'db> {
     /// Whether this item only exists for type checking purposes and
     /// will be missing at runtime
     pub is_type_check_only: bool,
-    /// Whether this item can definitively be used in a `raise` context.
+    /// Whether this item can definitively be used in the current context.
     ///
-    /// Note that this may not always be computed. (i.e., Only computed
-    /// when we are in a `raise` context.) And also note that if this
-    /// is `true`, then it's definitively usable in `raise`, but if
-    /// it's `false`, it _may_ still be usable in `raise`.
-    pub is_definitively_raisable: bool,
+    /// Some completions are computed based on contextual information.
+    /// If that's the case, we know this is a very precise completion
+    /// that should always be valid and can be preferred when
+    /// ordering completions.
+    pub is_context_specific: bool,
     /// The documentation associated with this item, if
     /// available.
     pub documentation: Option<Docstring>,
@@ -315,7 +316,7 @@ impl<'db> Completion<'db> {
             import: None,
             builtin: semantic.builtin,
             is_type_check_only,
-            is_definitively_raisable: false,
+            is_context_specific: false,
             documentation,
         }
     }
@@ -398,7 +399,7 @@ impl<'db> Completion<'db> {
             import: None,
             builtin: false,
             is_type_check_only: false,
-            is_definitively_raisable: false,
+            is_context_specific: false,
             documentation: None,
         }
     }
@@ -414,7 +415,7 @@ impl<'db> Completion<'db> {
             import: None,
             builtin: true,
             is_type_check_only: false,
-            is_definitively_raisable: false,
+            is_context_specific: false,
             documentation: None,
         }
     }
@@ -433,7 +434,7 @@ impl<'db> Completion<'db> {
             import: None,
             builtin: false,
             is_type_check_only: false,
-            is_definitively_raisable: false,
+            is_context_specific: true,
             documentation,
         }
     }
@@ -994,7 +995,7 @@ impl<'db> CollectionContext<'db> {
     #[allow(clippy::unused_self)]
     fn rank<'c>(&self, c: &'c Completion<'_>) -> Rank<'c> {
         Rank {
-            definitively_usable: if c.is_definitively_raisable {
+            definitively_usable: if c.is_context_specific {
                 Sort::Higher
             } else {
                 Sort::Even
@@ -1183,7 +1184,6 @@ fn add_function_arg_completions<'db>(
             if p.is_positional_only || set_function_args.contains(&p.name.as_str()) {
                 continue;
             }
-
             completions.add(Completion::argument(
                 &p.name,
                 p.ty,
@@ -1374,7 +1374,7 @@ fn add_unimported_completions<'db>(
             builtin: false,
             // TODO: `is_type_check_only` requires inferring the type of the symbol
             is_type_check_only: false,
-            is_definitively_raisable: false,
+            is_context_specific: false,
             documentation: None,
         });
     }
@@ -3088,9 +3088,9 @@ class Foo(<CURSOR>):
         );
 
         assert_snapshot!(builder.skip_keywords().skip_builtins().build().snapshot(), @"
+        metaclass=
         Bar
         Foo
-        metaclass=
         ");
     }
 
@@ -3106,9 +3106,9 @@ class Bar: ...
         );
 
         assert_snapshot!(builder.skip_keywords().skip_builtins().build().snapshot(), @"
+        metaclass=
         Bar
         Foo
-        metaclass=
         ");
     }
 
@@ -3124,9 +3124,9 @@ class Bar: ...
         );
 
         assert_snapshot!(builder.skip_keywords().skip_builtins().build().snapshot(), @"
+        metaclass=
         Bar
         Foo
-        metaclass=
         ");
     }
 
@@ -3140,9 +3140,9 @@ class Foo(<CURSOR>",
         );
 
         assert_snapshot!(builder.skip_keywords().skip_builtins().build().snapshot(), @"
+        metaclass=
         Bar
         Foo
-        metaclass=
         ");
     }
 
@@ -3804,8 +3804,8 @@ bar(o<CURSOR>
         assert_snapshot!(
             builder.skip_keywords().skip_builtins().skip_auto_import().build().snapshot(),
             @"
-        foo
         okay=
+        foo
         "
         );
     }
@@ -3825,8 +3825,8 @@ bar(o<CURSOR>
         assert_snapshot!(
             builder.skip_keywords().skip_builtins().skip_auto_import().build().snapshot(),
             @"
-        foo
         okay=
+        foo
         "
         );
     }
@@ -3940,10 +3940,10 @@ bar(o<CURSOR>
         assert_snapshot!(
             builder.skip_keywords().skip_builtins().skip_auto_import().build().snapshot(),
             @"
-        foo
         okay=
         okay_abc=
         okay_okay=
+        foo
         "
         );
     }
@@ -3961,9 +3961,9 @@ bar(<CURSOR>
         );
 
         assert_snapshot!(builder.skip_keywords().skip_builtins().build().snapshot(), @"
+        okay=
         bar
         foo
-        okay=
         ");
     }
 

crates/ty_ide/src/docstring.rs

@@ -218,6 +218,7 @@ fn render_markdown(docstring: &str) -> String {
                 output.push('\n');
             }
         }
+        first_line = false;
 
         // If we're in a literal block and we find a non-empty dedented line, end the block
         // TODO: we should remove all the trailing blank lines
@@ -273,6 +274,22 @@ fn render_markdown(docstring: &str) -> String {
                 block_indent = line_indent;
                 in_any_code = true;
                 in_markdown_with_fence = Some(fence.to_owned());
+                // Render the line verbatim without its indent and move on.
+                //
+                // If there's any indent this is really just Bad Syntax but it "makes sense"
+                // to someone writing docs like this:
+                //
+                // Returns:
+                //     Some details...
+                //     ```
+                //     some_example()
+                //     ```
+                //     etc etc...
+                //
+                // We "make this work" by stripping the indent on the fences but preserving the
+                // full indent of the lines between the fences
+                output.push_str(line);
+                continue;
             }
         // If we're in a markdown code fence and this line seems to terminate it, end the block
         } else if let Some(fence) = &in_markdown_with_fence
@@ -281,6 +298,9 @@ fn render_markdown(docstring: &str) -> String {
             in_any_code = false;
             block_indent = 0;
             in_markdown_with_fence = None;
+            // Render the line without its indent and move on.
+            output.push_str(line);
+            continue;
         }
 
         // If we're not in a codeblock and we see something that signals a literal block, start one
@@ -446,8 +466,6 @@ fn render_markdown(docstring: &str) -> String {
             // Print the line verbatim, it's in code
             output.push_str(line);
         }
-
-        first_line = false;
     }
     // Flush codeblock
     if in_any_code {
@@ -1208,6 +1226,74 @@ mod tests {
         ");
     }
 
+    // If an explicit markdown codefence is indented, eat the indent so it renders
+    // "the way the user expects" (as written this is basically invalid markdown,
+    // but it's nice if we handle it anyway because it makes visual sense).
+    #[test]
+    fn explicit_markdown_block_with_indent_tick() {
+        let docstring = r#"
+        My cool func...
+        
+        Returns:
+            Some details
+            `````python
+            x_y = thing_do();
+            ``` # this should't close the fence!
+            a_b = other_thing();
+            `````
+            And so on.
+        "#;
+
+        let docstring = Docstring::new(docstring.to_owned());
+
+        assert_snapshot!(docstring.render_markdown(), @r"
+        My cool func...  
+          
+        Returns:  
+            Some details  
+        `````python
+            x_y = thing_do();
+            ``` # this should't close the fence!
+            a_b = other_thing();
+        `````  
+            And so on.
+        ");
+    }
+
+    // If an explicit markdown codefence is indented, eat the indent so it renders
+    // "the way the user expects" (as written this is basically invalid markdown,
+    // but it's nice if we handle it anyway because it makes visual sense).
+    #[test]
+    fn explicit_markdown_block_with_indent_tilde() {
+        let docstring = r#"
+        My cool func...
+        
+        Returns:
+            Some details
+            ~~~~~~python
+            x_y = thing_do();
+            ~~~ # this should't close the fence!
+            a_b = other_thing();
+            ~~~~~~
+            And so on.
+        "#;
+
+        let docstring = Docstring::new(docstring.to_owned());
+
+        assert_snapshot!(docstring.render_markdown(), @r"
+        My cool func...  
+          
+        Returns:  
+            Some details  
+        ~~~~~~python
+            x_y = thing_do();
+            ~~~ # this should't close the fence!
+            a_b = other_thing();
+        ~~~~~~  
+            And so on.
+        ");
+    }
+
     // What do we do when we hit the end of the docstring with an unclosed markdown block?
     #[test]
     fn explicit_markdown_block_with_unclosed_fence_tick() {
@@ -1267,7 +1353,7 @@ mod tests {
         assert_snapshot!(docstring.render_markdown(), @r"
         My cool func:  
           
-                ``````we still think this is a codefence```
+        ``````we still think this is a codefence```
             x_y = thing_do();
         ```````````` and are sloppy as heck with indentation and closing shrugggg
         ");
@@ -1290,7 +1376,7 @@ mod tests {
         assert_snapshot!(docstring.render_markdown(), @r"
         My cool func:  
           
-                ~~~~~~we still think this is a codefence~~~
+        ~~~~~~we still think this is a codefence~~~
             x_y = thing_do();
         ~~~~~~~~~~~~~ and are sloppy as heck with indentation and closing shrugggg
         ");

crates/ty_module_resolver/src/list.rs

@@ -619,7 +619,7 @@ mod tests {
             list_snapshot(&db),
             @r#"
         [
-            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, None),
+            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, Some(Functools)),
         ]
         "#,
         );
@@ -662,7 +662,7 @@ mod tests {
             @r#"
         [
             Module::File("asyncio", "std-custom", "/typeshed/stdlib/asyncio/__init__.pyi", Package, None),
-            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, None),
+            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, Some(Functools)),
             Module::File("random", "std-custom", "/typeshed/stdlib/random.pyi", Module, None),
         ]
         "#,
@@ -755,7 +755,7 @@ mod tests {
         [
             Module::File("asyncio", "std-custom", "/typeshed/stdlib/asyncio/__init__.pyi", Package, None),
             Module::File("collections", "std-custom", "/typeshed/stdlib/collections/__init__.pyi", Package, Some(Collections)),
-            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, None),
+            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, Some(Functools)),
         ]
         "#,
         );
@@ -1091,7 +1091,7 @@ mod tests {
             list_snapshot(&db),
             @r#"
         [
-            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, None),
+            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, Some(Functools)),
         ]
         "#,
         );
@@ -1107,7 +1107,7 @@ mod tests {
             list_snapshot(&db),
             @r#"
         [
-            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, None),
+            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, Some(Functools)),
         ]
         "#,
         );
@@ -1129,7 +1129,7 @@ mod tests {
             list_snapshot(&db),
             @r#"
         [
-            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, None),
+            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, Some(Functools)),
         ]
         "#,
         );
@@ -1191,7 +1191,7 @@ mod tests {
             list_snapshot(&db),
             @r#"
         [
-            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, None),
+            Module::File("functools", "std-custom", "/typeshed/stdlib/functools.pyi", Module, Some(Functools)),
         ]
         "#,
         );

crates/ty_module_resolver/src/module.rs

@@ -320,6 +320,7 @@ pub enum KnownModule {
     Abc,
     Contextlib,
     Dataclasses,
+    Functools,
     Collections,
     Inspect,
     #[strum(serialize = "string.templatelib")]
@@ -351,6 +352,7 @@ impl KnownModule {
             Self::Abc => "abc",
             Self::Contextlib => "contextlib",
             Self::Dataclasses => "dataclasses",
+            Self::Functools => "functools",
             Self::Collections => "collections",
             Self::Inspect => "inspect",
             Self::TypeCheckerInternals => "_typeshed._type_checker_internals",
@@ -395,6 +397,10 @@ impl KnownModule {
     pub const fn is_importlib(self) -> bool {
         matches!(self, Self::ImportLib)
     }
+
+    pub const fn is_functools(self) -> bool {
+        matches!(self, Self::Functools)
+    }
 }
 
 impl std::fmt::Display for KnownModule {

crates/ty_module_resolver/src/path.rs

@@ -325,6 +325,10 @@ impl ModulePath {
             relative_path: relative_path.with_extension("py"),
         })
     }
+
+    pub(crate) fn into_search_path(self) -> SearchPath {
+        self.search_path
+    }
 }
 
 impl PartialEq<SystemPathBuf> for ModulePath {

crates/ty_module_resolver/src/resolve.rs

@@ -32,11 +32,8 @@ specifies ty's implementation of Python's import resolution algorithm.
 */
 
 use std::borrow::Cow;
-use std::fmt;
 use std::iter::FusedIterator;
-use std::str::Split;
 
-use compact_str::format_compact;
 use rustc_hash::{FxBuildHasher, FxHashSet};
 
 use ruff_db::files::{File, FilePath, FileRootKind};
@@ -1102,6 +1099,79 @@ fn desperately_resolve_name(
     resolve_name_impl(db, name, mode, search_paths.iter().flatten())
 }
 
+#[derive(Debug, Clone, Copy)]
+enum ResolvedModule {
+    NamespacePackage,
+    LegacyNamespacePackage(File),
+    RegularPackage(File),
+    Module(File),
+}
+
+#[derive(Debug, Clone)]
+struct ModuleResolutionCandidate {
+    path: ModulePath,
+    module: ResolvedModule,
+    py_typed: PyTyped,
+}
+
+impl ModuleResolutionCandidate {
+    // Is this some kind of namespace package?
+    fn is_any_namespace_package(&self) -> bool {
+        match self.module {
+            ResolvedModule::NamespacePackage => true,
+            ResolvedModule::LegacyNamespacePackage(_) => true,
+            ResolvedModule::RegularPackage(_) => false,
+            ResolvedModule::Module(_) => false,
+        }
+    }
+
+    // This is the module we were actually interested in resolving, complete the resolution
+    fn into_resolved_name(self) -> ResolvedName {
+        match self.module {
+            ResolvedModule::NamespacePackage => ResolvedName::NamespacePackage,
+            // legacy namespace packages behave like regular packages when they're the target of the resolution
+            ResolvedModule::LegacyNamespacePackage(file) => {
+                ResolvedName::FileModule(ResolvedFileModule {
+                    kind: ModuleKind::Package,
+                    search_path: self.path.into_search_path(),
+                    file,
+                })
+            }
+            ResolvedModule::RegularPackage(file) => ResolvedName::FileModule(ResolvedFileModule {
+                kind: ModuleKind::Package,
+                search_path: self.path.into_search_path(),
+                file,
+            }),
+            ResolvedModule::Module(file) => ResolvedName::FileModule(ResolvedFileModule {
+                kind: ModuleKind::Module,
+                search_path: self.path.into_search_path(),
+                file,
+            }),
+        }
+    }
+
+    fn missing_submodule_is_terminal(&self) -> bool {
+        if matches!(self.py_typed, PyTyped::Partial) {
+            return false;
+        }
+
+        // Only regular packages are truly terminal, as a later `foo/__init__.py`
+        // can shadow `foo.py`. Both shadow namespace packages.
+        matches!(self.module, ResolvedModule::RegularPackage(_))
+    }
+
+    fn to_str<'a>(&self, db: &'a dyn Db) -> Cow<'a, str> {
+        match self.module {
+            ResolvedModule::NamespacePackage => {
+                Cow::Owned(self.path.to_system_path().unwrap_or_default().to_string())
+            }
+            ResolvedModule::LegacyNamespacePackage(file) => Cow::Borrowed(file.path(db).as_str()),
+            ResolvedModule::RegularPackage(file) => Cow::Borrowed(file.path(db).as_str()),
+            ResolvedModule::Module(file) => Cow::Borrowed(file.path(db).as_str()),
+        }
+    }
+}
+
 fn resolve_name_impl<'a>(
     db: &dyn Db,
     name: &ModuleName,
@@ -1109,109 +1179,250 @@ fn resolve_name_impl<'a>(
     search_paths: impl Iterator<Item = &'a SearchPath>,
 ) -> Option<ResolvedName> {
     let python_version = db.python_version();
-    let resolver_state = ResolverContext::new(db, python_version, mode);
+    let context = ResolverContext::new(db, python_version, mode);
     let is_non_shadowable = mode.is_non_shadowable(python_version.minor, name.as_str());
+    let mut stub_name = None;
 
-    let name = RelaxedModuleName::new(name);
-    let stub_name = name.to_stub_package();
-    let mut is_namespace_package = false;
+    let mut cur_candidates = search_paths
+        .filter_map(|search_path| {
+            // When a builtin module is imported, standard module resolution is bypassed:
+            // the module name always resolves to the stdlib module,
+            // even if there's a module of the same name in the first-party root
+            // (which would normally result in the stdlib module being overridden).
+            // TODO: offer a diagnostic if there is a first-party module of the same name
+            if is_non_shadowable && !search_path.is_standard_library() {
+                return None;
+            }
 
-    for search_path in search_paths {
-        // When a builtin module is imported, standard module resolution is bypassed:
-        // the module name always resolves to the stdlib module,
-        // even if there's a module of the same name in the first-party root
-        // (which would normally result in the stdlib module being overridden).
-        // TODO: offer a diagnostic if there is a first-party module of the same name
-        if is_non_shadowable && !search_path.is_standard_library() {
-            continue;
-        }
+            Some(ModuleResolutionCandidate {
+                path: search_path.to_module_path(),
+                module: ResolvedModule::NamespacePackage,
+                py_typed: PyTyped::Untyped,
+            })
+        })
+        .collect::<Vec<_>>();
+    let mut next_candidates = vec![];
 
-        if !search_path.is_standard_library() && resolver_state.mode.stubs_allowed() {
-            match resolve_name_in_search_path(&resolver_state, &stub_name, search_path) {
-                Ok((package_kind, _, ResolvedName::FileModule(module))) => {
-                    if package_kind.is_root() && module.kind.is_module() {
+    // FIXME?: because we have to search every candidate on each step of this loop,
+    // in theory we can search them all in parallel. However we need to join the parallelism
+    // at the end of each iteration, and after the first iteration in 99% of cases we will have
+    // reduced down to a single candidate, so maybe meh?
+    let mut is_root = true;
+    for component in name.components() {
+        // Search for the next component in every search-path
+        for mut candidate in cur_candidates.drain(..) {
+            // On the first iteration, look for `mypackage-stubs` as well
+            // Optimization: stdlib never has these `-stubs`
+            if is_root
+                && context.mode.stubs_allowed()
+                && !candidate.path.search_path().is_standard_library()
+            {
+                let stub_name = stub_name.get_or_insert_with(|| format!("{component}-stubs"));
+                let mut stub_candidate = candidate.clone();
+                if resolve_name_in_search_path(&context, &mut stub_candidate, stub_name).is_ok() {
+                    // `mypackage-stubs.py(i)` is not a valid result
+                    if matches!(stub_candidate.module, ResolvedModule::Module(_)) {
                         tracing::trace!(
-                            "Search path `{search_path}` contains a module \
-                             named `{stub_name}` but a standalone module isn't a valid stub."
+                            "Search path `{}` contains a module \
+                            named `{stub_name}` but a standalone module isn't a valid stub.",
+                            candidate.path.search_path()
                         );
                     } else {
-                        return Some(ResolvedName::FileModule(module));
+                        let shadows_all = stub_candidate.missing_submodule_is_terminal();
+                        next_candidates.push(stub_candidate);
+                        if shadows_all {
+                            break;
+                        }
                     }
                 }
-                Ok((_, _, ResolvedName::NamespacePackage)) => {
-                    is_namespace_package = true;
-                }
-                Err((PackageKind::Root, _)) => {
-                    tracing::trace!(
-                        "Search path `{search_path}` contains no stub package named `{stub_name}`."
-                    );
-                }
-                Err((PackageKind::Regular, PyTyped::Partial)) => {
-                    tracing::trace!(
-                        "Stub-package in `{search_path}` doesn't contain module: \
-                         `{name}` but it is a partial package, keep going."
-                    );
-                    // stub exists, but the module doesn't. But this is a partial package,
-                    // fall through to looking for a non-stub package
-                }
-                Err((PackageKind::Regular, _)) => {
-                    tracing::trace!(
-                        "Stub-package in `{search_path}` doesn't contain module: `{name}`"
-                    );
-                    // stub exists, but the module doesn't.
-                    return None;
-                }
-                Err((PackageKind::Namespace, _)) => {
-                    tracing::trace!(
-                        "Stub-package in `{search_path}` doesn't contain module: \
-                         `{name}` but it is a namespace package, keep going."
-                    );
-                    // stub exists, but the module doesn't. But this is a namespace package,
-                    // fall through to looking for a non-stub package
+            }
+
+            if resolve_name_in_search_path(&context, &mut candidate, component).is_err() {
+                if candidate.missing_submodule_is_terminal() {
+                    // Everything after this package should be shadowed out by this failure
+                    // But the previous results are still in play because they would have
+                    // shadowed this one out anyway.
+                    break;
                 }
+                continue;
+            }
+            let shadows_all = candidate.missing_submodule_is_terminal();
+            next_candidates.push(candidate);
+            if shadows_all {
+                break;
             }
         }
 
-        match resolve_name_in_search_path(&resolver_state, &name, search_path) {
-            Ok((_, _, ResolvedName::FileModule(module))) => {
-                return Some(ResolvedName::FileModule(module));
+        // Now that we have several candidates, we need to reject candidates that are shadowed.
+        // There are only two valid situations where we should proceed into the next iteration
+        // with multiple candidates:
+        //
+        // * All the candidates are namespace packages
+        // * `mypackage-stubs` is a candidate with `PyTyped::Partial`
+        //
+        // The existence of a single non-namespace package will shadow
+        // all namespace packages *regardless of search-path order*.
+        //
+        // Similarly, the existence of a single regular package will shadow
+        // all modules (mymod.py) *regardless of search-path order*.
+        //
+        // This is implemented with the `retain` that follows.
+        //
+        // We can't do this "delete all namespace packages" eagerly because we want a
+        // `PyTyped::Partial` regular package to shadow namespace packages after it.
+        // (FIXME: I guess we could just set a flag not to add them...)
+
+        // First record what kinds of things we found
+        let mut found_regular_package = None;
+        let mut found_module = None;
+        let mut found_legacy_namespace_package = None;
+        for candidate in &next_candidates {
+            match (candidate.module, candidate.py_typed) {
+                (ResolvedModule::LegacyNamespacePackage(file), _) => {
+                    found_legacy_namespace_package = Some(file);
+                }
+                (ResolvedModule::RegularPackage(file), PyTyped::Untyped | PyTyped::Full) => {
+                    found_regular_package = Some(file);
+                }
+                (ResolvedModule::Module(file), PyTyped::Untyped | PyTyped::Full) => {
+                    found_module = Some(file);
+                }
+                _ => {}
             }
-            Ok((_, _, ResolvedName::NamespacePackage)) => {
-                is_namespace_package = true;
+        }
+
+        next_candidates.retain(|candidate| {
+            if let Some(_legacy) = found_legacy_namespace_package && !matches!(candidate.module, ResolvedModule::LegacyNamespacePackage(_)) {
+                // TODO: it would be nice to emit a warning about this but we just assume it's fine
+            }
+
+            // Regular packages shadow anything that isn't a regular package independent of order
+            if let Some(package) = found_regular_package && !matches!(candidate.module, ResolvedModule::RegularPackage(_)) {
+                tracing::trace!("Discarding namespace package `{}` because a regular package of the same name was found: {}", 
+                    candidate.to_str(db),
+                    package.path(db).as_str(),
+                );
+                return false;
+            }
+            // Modules shadow namespace packages independent of order
+            if let Some(module) = found_module && candidate.is_any_namespace_package() {
+                tracing::trace!("Discarding namespace package `{}` because a module of the same name was found: {}", 
+                    candidate.to_str(db),
+                    module.path(db).as_str(),
+                );
+                return false;
+            }
+            true
+        });
+
+        if next_candidates.is_empty() {
+            return None;
+        }
+
+        // Advance to the next level of candidates while reusing allocations
+        // (we used `drain` so cur_candidates is empty)
+        std::mem::swap(&mut cur_candidates, &mut next_candidates);
+        is_root = false;
+    }
+
+    // We now have a list of candidates that are all correct answers, and we just need to take the
+    // Best one. Because of the filtering we've done in the loop, and sorting stub-packages to come
+    // first, this is in fact just "the first one".
+    cur_candidates
+        .into_iter()
+        .next()
+        .map(ModuleResolutionCandidate::into_resolved_name)
+}
+
+/// Attempts to resolve a module name in a particular search path.
+///
+/// `search_path` should be the directory to start looking for the module.
+///
+/// `name` should be a complete non-empty module name, e.g, `foo` or
+/// `foo.bar.baz`.
+///
+/// Upon success, this returns the kind of the parent package (root, regular
+/// package or namespace package) along with the resolved details of the
+/// module: its kind (single-file module or package), the search path in
+/// which it was found (guaranteed to be equal to the one given) and the
+/// corresponding `File`.
+///
+/// Upon error, the kind of the parent package is returned.
+fn resolve_name_in_search_path(
+    context: &ResolverContext,
+    candidate: &mut ModuleResolutionCandidate,
+    module_name: &str,
+) -> Result<(), ()> {
+    if matches!(candidate.module, ResolvedModule::Module(_)) {
+        tracing::trace!(
+            "The non-package {} cannot have child",
+            candidate.to_str(context.db)
+        );
+        return Err(());
+    }
+    let package_path = &mut candidate.path;
+    package_path.push(module_name);
+
+    // Check for a regular package first (highest priority)
+    package_path.push("__init__");
+    if let Some(init) = resolve_file_module(package_path, context) {
+        // Remove the `__init__` component for any potential next step
+        package_path.pop();
+        candidate.py_typed = package_path
+            .py_typed(context)
+            .inherit_parent(candidate.py_typed);
+        if is_legacy_namespace_package(package_path, context, init) {
+            candidate.module = ResolvedModule::LegacyNamespacePackage(init);
+        } else {
+            candidate.module = ResolvedModule::RegularPackage(init);
+        }
+        return Ok(());
+    }
+
+    // Check for a file module next
+    package_path.pop();
+
+    if let Some(file_module) = resolve_file_module(package_path, context) {
+        candidate.module = ResolvedModule::Module(file_module);
+        return Ok(());
+    }
+
+    // Last resort, check if a folder with the given name exists. If so,
+    // then this is a namespace package. We need to skip this check for
+    // typeshed because the `resolve_file_module` can also return `None` if the
+    // `__init__.py` exists but isn't available for the current Python version.
+    // Let's assume that the `xml` module is only available on Python 3.11+ and
+    // we're resolving for Python 3.10:
+    //
+    // * `resolve_file_module("xml/__init__.pyi")` returns `None` even though
+    //   the file exists but the module isn't available for the current Python
+    //   version.
+    // * The check here would now return `true` because the `xml` directory
+    //   exists, resulting in a false positive for a namespace package.
+    //
+    // Since typeshed doesn't use any namespace packages today (May 2025),
+    // simply skip this check which also helps performance. If typeshed
+    // ever uses namespace packages, ensure that this check also takes the
+    // `VERSIONS` file into consideration.
+    if !package_path.search_path().is_standard_library() && package_path.is_directory(context) {
+        if let Some(path) = package_path.to_system_path() {
+            let system = context.db.system();
+            if system.case_sensitivity().is_case_sensitive()
+                || system.path_exists_case_sensitive(
+                    &path,
+                    package_path.search_path().as_system_path().unwrap(),
+                )
+            {
+                candidate.py_typed = package_path
+                    .py_typed(context)
+                    .inherit_parent(candidate.py_typed);
+                candidate.module = ResolvedModule::NamespacePackage;
+                return Ok(());
             }
-            Err(kind) => match kind {
-                (PackageKind::Root, _) => {
-                    tracing::trace!(
-                        "Search path `{search_path}` contains no package named `{name}`."
-                    );
-                }
-                (PackageKind::Regular, PyTyped::Partial) => {
-                    tracing::trace!(
-                        "Package in `{search_path}` doesn't contain module: \
-                         `{name}` but it is a partial package, keep going."
-                    );
-                }
-                (PackageKind::Regular, _) => {
-                    // For regular packages, don't search the next search path. All files of that
-                    // package must be in the same location
-                    tracing::trace!("Package in `{search_path}` doesn't contain module: `{name}`");
-                    return None;
-                }
-                (PackageKind::Namespace, _) => {
-                    tracing::trace!(
-                        "Package in `{search_path}` doesn't contain module: \
-                         `{name}` but it is a namespace package, keep going."
-                    );
-                }
-            },
         }
     }
 
-    if is_namespace_package {
-        return Some(ResolvedName::NamespacePackage);
-    }
-
-    None
+    Err(())
 }
 
 #[derive(Debug)]
@@ -1234,101 +1445,6 @@ struct ResolvedFileModule {
     file: File,
 }
 
-/// Attempts to resolve a module name in a particular search path.
-///
-/// `search_path` should be the directory to start looking for the module.
-///
-/// `name` should be a complete non-empty module name, e.g, `foo` or
-/// `foo.bar.baz`.
-///
-/// Upon success, this returns the kind of the parent package (root, regular
-/// package or namespace package) along with the resolved details of the
-/// module: its kind (single-file module or package), the search path in
-/// which it was found (guaranteed to be equal to the one given) and the
-/// corresponding `File`.
-///
-/// Upon error, the kind of the parent package is returned.
-fn resolve_name_in_search_path(
-    context: &ResolverContext,
-    name: &RelaxedModuleName,
-    search_path: &SearchPath,
-) -> Result<(PackageKind, PyTyped, ResolvedName), (PackageKind, PyTyped)> {
-    let mut components = name.components();
-    let module_name = components.next_back().unwrap();
-
-    let resolved_package = resolve_package(search_path, components, context)?;
-
-    let mut package_path = resolved_package.path;
-
-    package_path.push(module_name);
-
-    // Check for a regular package first (highest priority)
-    package_path.push("__init__");
-    if let Some(regular_package) = resolve_file_module(&package_path, context) {
-        return Ok((
-            resolved_package.kind,
-            resolved_package.typed,
-            ResolvedName::FileModule(ResolvedFileModule {
-                search_path: search_path.clone(),
-                kind: ModuleKind::Package,
-                file: regular_package,
-            }),
-        ));
-    }
-
-    // Check for a file module next
-    package_path.pop();
-
-    if let Some(file_module) = resolve_file_module(&package_path, context) {
-        return Ok((
-            resolved_package.kind,
-            resolved_package.typed,
-            ResolvedName::FileModule(ResolvedFileModule {
-                file: file_module,
-                kind: ModuleKind::Module,
-                search_path: search_path.clone(),
-            }),
-        ));
-    }
-
-    // Last resort, check if a folder with the given name exists. If so,
-    // then this is a namespace package. We need to skip this check for
-    // typeshed because the `resolve_file_module` can also return `None` if the
-    // `__init__.py` exists but isn't available for the current Python version.
-    // Let's assume that the `xml` module is only available on Python 3.11+ and
-    // we're resolving for Python 3.10:
-    //
-    // * `resolve_file_module("xml/__init__.pyi")` returns `None` even though
-    //   the file exists but the module isn't available for the current Python
-    //   version.
-    // * The check here would now return `true` because the `xml` directory
-    //   exists, resulting in a false positive for a namespace package.
-    //
-    // Since typeshed doesn't use any namespace packages today (May 2025),
-    // simply skip this check which also helps performance. If typeshed
-    // ever uses namespace packages, ensure that this check also takes the
-    // `VERSIONS` file into consideration.
-    if !search_path.is_standard_library() && package_path.is_directory(context) {
-        if let Some(path) = package_path.to_system_path() {
-            let system = context.db.system();
-            if system.case_sensitivity().is_case_sensitive()
-                || system.path_exists_case_sensitive(
-                    &path,
-                    package_path.search_path().as_system_path().unwrap(),
-                )
-            {
-                return Ok((
-                    resolved_package.kind,
-                    resolved_package.typed,
-                    ResolvedName::NamespacePackage,
-                ));
-            }
-        }
-    }
-
-    Err((resolved_package.kind, resolved_package.typed))
-}
-
 /// If `module` exists on disk with either a `.pyi` or `.py` extension,
 /// return the [`File`] corresponding to that path.
 ///
@@ -1366,90 +1482,6 @@ pub(super) fn resolve_file_module(
     Some(file)
 }
 
-/// Attempt to resolve the parent package of a module.
-///
-/// `module_search_path` should be the directory to start looking for the
-/// parent package.
-///
-/// `components` should be the full module name of the parent package. This
-/// specifically should not include the basename of the module. So e.g.,
-/// for `foo.bar.baz`, `components` should be `[foo, bar]`. It follows that
-/// `components` may be empty (in which case, the parent package is the root).
-///
-/// Upon success, the path to the package and its "kind" (root, regular or
-/// namespace) is returned. Upon error, the kind of the package is still
-/// returned based on how many components were found and whether `__init__.py`
-/// is present.
-fn resolve_package<'a, 'db, I>(
-    module_search_path: &SearchPath,
-    components: I,
-    resolver_state: &ResolverContext<'db>,
-) -> Result<ResolvedPackage, (PackageKind, PyTyped)>
-where
-    I: Iterator<Item = &'a str>,
-{
-    let mut package_path = module_search_path.to_module_path();
-
-    // `true` if inside a folder that is a namespace package (has no `__init__.py`).
-    // Namespace packages are special because they can be spread across multiple search paths.
-    // https://peps.python.org/pep-0420/
-    let mut in_namespace_package = false;
-
-    // `true` if resolving a sub-package. For example, `true` when resolving `bar` of `foo.bar`.
-    let mut in_sub_package = false;
-
-    let mut typed = package_path.py_typed(resolver_state);
-
-    // For `foo.bar.baz`, test that `foo` and `bar` both contain a `__init__.py`.
-    for folder in components {
-        package_path.push(folder);
-        typed = package_path.py_typed(resolver_state).inherit_parent(typed);
-
-        let is_regular_package = package_path.is_regular_package(resolver_state);
-
-        if is_regular_package {
-            // This is the only place where we need to consider the existence of legacy namespace
-            // packages, as we are explicitly searching for the *parent* package of the module
-            // we actually want. Here, such a package should be treated as a PEP-420 ("modern")
-            // namespace package. In all other contexts it acts like a normal package and needs
-            // no special handling.
-            in_namespace_package = is_legacy_namespace_package(&package_path, resolver_state);
-        } else if package_path.is_directory(resolver_state)
-            // Pure modules hide namespace packages with the same name
-            && resolve_file_module(&package_path, resolver_state).is_none()
-        {
-            // A directory without an `__init__.py(i)` is a namespace package,
-            // continue with the next folder.
-            in_namespace_package = true;
-        } else if in_namespace_package {
-            // Package not found but it is part of a namespace package.
-            return Err((PackageKind::Namespace, typed));
-        } else if in_sub_package {
-            // A regular sub package wasn't found.
-            return Err((PackageKind::Regular, typed));
-        } else {
-            // We couldn't find `foo` for `foo.bar.baz`, search the next search path.
-            return Err((PackageKind::Root, typed));
-        }
-
-        in_sub_package = true;
-    }
-
-    let kind = if in_namespace_package {
-        PackageKind::Namespace
-    } else if in_sub_package {
-        PackageKind::Regular
-    } else {
-        PackageKind::Root
-    };
-
-    Ok(ResolvedPackage {
-        kind,
-        path: package_path,
-        typed,
-    })
-}
-
 /// Determines whether a package is a legacy namespace package.
 ///
 /// Before PEP 420 introduced implicit namespace packages, the ecosystem developed
@@ -1479,19 +1511,14 @@ where
 /// we will just get confused if you mess it up).
 fn is_legacy_namespace_package(
     package_path: &ModulePath,
-    resolver_state: &ResolverContext,
+    context: &ResolverContext,
+    init: File,
 ) -> bool {
     // Just an optimization, the stdlib and typeshed are never legacy namespace packages
     if package_path.search_path().is_standard_library() {
         return false;
     }
 
-    let mut package_path = package_path.clone();
-    package_path.push("__init__");
-    let Some(init) = resolve_file_module(&package_path, resolver_state) else {
-        return false;
-    };
-
     // This is all syntax-only analysis so it *could* be fooled but it's really unlikely.
     //
     // The benefit of being syntax-only is speed and avoiding circular dependencies
@@ -1499,44 +1526,13 @@ fn is_legacy_namespace_package(
     //
     // The downside is if you write slightly different syntax we will fail to detect the idiom,
     // but hey, this is better than nothing!
-    let parsed = ruff_db::parsed::parsed_module(resolver_state.db, init);
+    let parsed = ruff_db::parsed::parsed_module(context.db, init);
     let mut visitor = LegacyNamespacePackageVisitor::default();
-    visitor.visit_body(parsed.load(resolver_state.db).suite());
+    visitor.visit_body(parsed.load(context.db).suite());
 
     visitor.is_legacy_namespace_package
 }
 
-#[derive(Debug)]
-struct ResolvedPackage {
-    path: ModulePath,
-    kind: PackageKind,
-    typed: PyTyped,
-}
-
-#[derive(Copy, Clone, Eq, PartialEq, Debug)]
-enum PackageKind {
-    /// A root package or module. E.g. `foo` in `foo.bar.baz` or just `foo`.
-    Root,
-
-    /// A regular sub-package where the parent contains an `__init__.py`.
-    ///
-    /// For example, `bar` in `foo.bar` when the `foo` directory contains an `__init__.py`.
-    Regular,
-
-    /// A sub-package in a namespace package. A namespace package is a package
-    /// without an `__init__.py`.
-    ///
-    /// For example, `bar` in `foo.bar` if the `foo` directory contains no
-    /// `__init__.py`.
-    Namespace,
-}
-
-impl PackageKind {
-    pub(crate) const fn is_root(self) -> bool {
-        matches!(self, PackageKind::Root)
-    }
-}
-
 /// Info about the `py.typed` file for this package
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]
 pub(crate) enum PyTyped {
@@ -1587,34 +1583,6 @@ impl<'db> ResolverContext<'db> {
     }
 }
 
-/// A [`ModuleName`] but with relaxed semantics to allow `<package>-stubs.path`
-#[derive(Debug)]
-struct RelaxedModuleName(compact_str::CompactString);
-
-impl RelaxedModuleName {
-    fn new(name: &ModuleName) -> Self {
-        Self(name.as_str().into())
-    }
-
-    fn components(&self) -> Split<'_, char> {
-        self.0.split('.')
-    }
-
-    fn to_stub_package(&self) -> Self {
-        if let Some((package, rest)) = self.0.split_once('.') {
-            Self(format_compact!("{package}-stubs.{rest}"))
-        } else {
-            Self(format_compact!("{package}-stubs", package = self.0))
-        }
-    }
-}
-
-impl fmt::Display for RelaxedModuleName {
-    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        self.0.fmt(f)
-    }
-}
-
 /// Detects if a module contains a statement of the form:
 /// ```python
 /// __path__ = pkgutil.extend_path(__path__, __name__)
@@ -1926,14 +1894,12 @@ mod tests {
             asyncio: 3.8-               # 'Regular' package on py38+
             asyncio.tasks: 3.9-3.11     # Submodule on py39+ only
             functools: 3.8-             # Top-level single-file module
-            xml: 3.8-3.8                # Namespace package on py38 only
         ";
 
         const STDLIB: &[FileSpec] = &[
             ("asyncio/__init__.pyi", ""),
             ("asyncio/tasks.pyi", ""),
             ("functools.pyi", ""),
-            ("xml/etree.pyi", ""),
         ];
 
         const TYPESHED: MockedTypeshed = MockedTypeshed {
@@ -1946,7 +1912,7 @@ mod tests {
             .with_python_version(PythonVersion::PY38)
             .build();
 
-        let existing_modules = create_module_names(&["asyncio", "functools", "xml.etree"]);
+        let existing_modules = create_module_names(&["asyncio", "functools"]);
         for module_name in existing_modules {
             let resolved_module =
                 resolve_module_confident(&db, &module_name).unwrap_or_else(|| {
@@ -1970,16 +1936,12 @@ mod tests {
             asyncio: 3.8-               # 'Regular' package on py38+
             asyncio.tasks: 3.9-3.11     # Submodule on py39+ only
             collections: 3.9-           # 'Regular' package on py39+
-            importlib: 3.9-             # Namespace package on py39+
-            xml: 3.8-3.8                # Namespace package on 3.8 only
         ";
 
         const STDLIB: &[FileSpec] = &[
             ("collections/__init__.pyi", ""),
             ("asyncio/__init__.pyi", ""),
             ("asyncio/tasks.pyi", ""),
-            ("importlib/abc.pyi", ""),
-            ("xml/etree.pyi", ""),
         ];
 
         const TYPESHED: MockedTypeshed = MockedTypeshed {
@@ -1992,13 +1954,7 @@ mod tests {
             .with_python_version(PythonVersion::PY38)
             .build();
 
-        let nonexisting_modules = create_module_names(&[
-            "collections",
-            "importlib",
-            "importlib.abc",
-            "xml",
-            "asyncio.tasks",
-        ]);
+        let nonexisting_modules = create_module_names(&["collections", "asyncio.tasks"]);
 
         for module_name in nonexisting_modules {
             assert!(
@@ -2015,7 +1971,6 @@ mod tests {
             asyncio.tasks: 3.9-3.11     # Submodule on py39+ only
             collections: 3.9-           # 'Regular' package on py39+
             functools: 3.8-             # Top-level single-file module
-            importlib: 3.9-             # Namespace package on py39+
         ";
 
         const STDLIB: &[FileSpec] = &[
@@ -2023,7 +1978,6 @@ mod tests {
             ("asyncio/tasks.pyi", ""),
             ("collections/__init__.pyi", ""),
             ("functools.pyi", ""),
-            ("importlib/abc.pyi", ""),
         ];
 
         const TYPESHED: MockedTypeshed = MockedTypeshed {
@@ -2036,13 +1990,8 @@ mod tests {
             .with_python_version(PythonVersion::PY39)
             .build();
 
-        let existing_modules = create_module_names(&[
-            "asyncio",
-            "functools",
-            "importlib.abc",
-            "collections",
-            "asyncio.tasks",
-        ]);
+        let existing_modules =
+            create_module_names(&["asyncio", "functools", "collections", "asyncio.tasks"]);
 
         for module_name in existing_modules {
             let resolved_module =
@@ -2444,7 +2393,7 @@ mod tests {
     fn adding_file_to_search_path_with_lower_priority_does_not_invalidate_query() {
         const TYPESHED: MockedTypeshed = MockedTypeshed {
             versions: "functools: 3.8-",
-            stdlib_files: &[("functools.pyi", "def update_wrapper(): ...")],
+            stdlib_files: &[("functools/__init__.pyi", "def update_wrapper(): ...")],
         };
 
         let TestCase {
@@ -2458,7 +2407,7 @@ mod tests {
             .build();
 
         let functools_module_name = ModuleName::new_static("functools").unwrap();
-        let stdlib_functools_path = stdlib.join("functools.pyi");
+        let stdlib_functools_path = stdlib.join("functools/__init__.pyi");
 
         let functools_module = resolve_module_confident(&db, &functools_module_name).unwrap();
         assert_eq!(functools_module.search_path(&db).unwrap(), &stdlib);
@@ -2470,7 +2419,7 @@ mod tests {
         // Adding a file to site-packages does not invalidate the query,
         // since site-packages takes lower priority in the module resolution
         db.clear_salsa_events();
-        let site_packages_functools_path = site_packages.join("functools.py");
+        let site_packages_functools_path = site_packages.join("functools/__init__.py");
         db.write_file(&site_packages_functools_path, "f: int")
             .unwrap();
         let functools_module = resolve_module_confident(&db, &functools_module_name).unwrap();

crates/ty_project/Cargo.toml

@@ -14,6 +14,7 @@ license.workspace = true
 [dependencies]
 ruff_cache = { workspace = true }
 ruff_db = { workspace = true, features = ["cache", "serde"] }
+ruff_diagnostics = { workspace = true }
 ruff_macros = { workspace = true }
 ruff_memory_usage = { workspace = true }
 ruff_options_metadata = { workspace = true }
@@ -30,7 +31,7 @@ anyhow = { workspace = true }
 camino = { workspace = true }
 colored = { workspace = true }
 crossbeam = { workspace = true }
-get-size2 = { workspace = true }
+get-size2 = { workspace = true, features = ["ordermap"] }
 globset = { workspace = true }
 notify = { workspace = true }
 ordermap = { workspace = true, features = ["serde"] }
@@ -48,8 +49,10 @@ toml = { workspace = true }
 tracing = { workspace = true }
 
 [dev-dependencies]
-insta = { workspace = true, features = ["redactions", "ron"] }
 ruff_db = { workspace = true, features = ["testing"] }
+ruff_python_trivia = { workspace = true }
+
+insta = { workspace = true, features = ["redactions", "ron"] }
 
 [features]
 default = ["zstd"]

crates/ty_project/src/fixes.rs

@@ -0,0 +1,794 @@
+use ruff_db::cancellation::{Canceled, CancellationToken};
+use ruff_db::diagnostic::{DisplayDiagnosticConfig, DisplayDiagnostics};
+use ruff_db::parsed::parsed_module;
+use ruff_db::source::SourceText;
+use ruff_db::system::{SystemPath, WritableSystem};
+use ruff_db::{
+    diagnostic::{Annotation, Diagnostic, DiagnosticId, Severity, Span},
+    files::File,
+    source::source_text,
+};
+use ruff_diagnostics::{Fix, IsolationLevel, SourceMap};
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
+use rustc_hash::FxHashSet;
+use salsa::Setter as _;
+use std::collections::BTreeMap;
+use thiserror::Error;
+use ty_python_semantic::{UNUSED_IGNORE_COMMENT, suppress_all};
+
+use crate::Db;
+
+pub struct SuppressAllResult {
+    /// The non-lint diagnostics that can't be suppressed or the diagnostics of files
+    /// that couldn't be suppressed (because ty failed to write the result back to disk,
+    /// or the file contains syntax errors).
+    pub diagnostics: Vec<Diagnostic>,
+
+    /// The number of diagnostics that were suppressed.
+    pub count: usize,
+}
+
+/// Adds suppressions to all lint diagnostics and writes the changed files back to disk.
+///
+/// Returns how many diagnostics were suppressed along the remaining, non-suppressed diagnostics.
+///
+/// ## Panics
+/// If the `db`'s system isn't [writable](WritableSystem).
+pub fn suppress_all_diagnostics(
+    db: &mut dyn Db,
+    mut diagnostics: Vec<Diagnostic>,
+    cancellation_token: &CancellationToken,
+) -> Result<SuppressAllResult, Canceled> {
+    let system = WritableSystem::dyn_clone(
+        db.system()
+            .as_writable()
+            .expect("System should be writable"),
+    );
+
+    let has_fixable = diagnostics.iter().any(|diagnostic| {
+        diagnostic
+            .primary_span()
+            .and_then(|span| span.range())
+            .is_some()
+            && diagnostic.id().is_lint()
+            && diagnostic.id() != DiagnosticId::Lint(UNUSED_IGNORE_COMMENT.name())
+    });
+
+    // Early return if there are no diagnostics that can be suppressed to avoid all the heavy work below.
+    if !has_fixable {
+        return Ok(SuppressAllResult {
+            diagnostics,
+            count: 0,
+        });
+    }
+
+    let mut by_file: BTreeMap<File, Vec<_>> = BTreeMap::new();
+
+    // Group the diagnostics by file, leave the file-agnostic diagnostics in `diagnostics`.
+    for diagnostic in diagnostics.extract_if(.., |diagnostic| diagnostic.primary_span().is_some()) {
+        let span = diagnostic
+            .primary_span()
+            .expect("should be set because `extract_if` only yields elements with a primary_span");
+
+        by_file
+            .entry(span.expect_ty_file())
+            .or_default()
+            .push(diagnostic);
+    }
+
+    let mut fixed_count = 0usize;
+    let project = db.project();
+
+    // Try to suppress all lint-diagnostics in the given file.
+    for (&file, file_diagnostics) in &mut by_file {
+        if cancellation_token.is_cancelled() {
+            return Err(Canceled);
+        }
+
+        let Some(path) = file.path(db).as_system_path() else {
+            tracing::debug!(
+                "Skipping file `{}` with non-system path because vendored and system virtual file paths are read-only",
+                file.path(db)
+            );
+
+            continue;
+        };
+
+        let parsed = parsed_module(db, file);
+        if parsed.load(db).has_syntax_errors() {
+            tracing::warn!("Skipping file `{path}` with syntax errors",);
+            continue;
+        }
+
+        let fixable_diagnostics: Vec<_> = file_diagnostics
+            .iter()
+            .filter_map(|diagnostic| {
+                let lint_id = diagnostic.id().as_lint()?;
+
+                // Don't suppress unused ignore comments.
+                if lint_id == UNUSED_IGNORE_COMMENT.name() {
+                    return None;
+                }
+
+                // We can't suppress diagnostics without a corresponding file or range.
+                let span = diagnostic.primary_span()?;
+                let range = span.range()?;
+
+                Some((lint_id, range))
+            })
+            .collect();
+
+        if fixable_diagnostics.is_empty() {
+            tracing::debug!(
+                "Skipping file `{path}` because it contains no suppressable diagnostics"
+            );
+            continue;
+        }
+
+        tracing::debug!(
+            "Suppressing {} diagnostics in `{path}`.",
+            fixable_diagnostics.len()
+        );
+
+        // Required to work around borrow checker issues.
+        let path = path.to_path_buf();
+        let fixes = suppress_all(db, file, &fixable_diagnostics);
+        let source = source_text(db, file);
+
+        // TODO: Handle overlapping fixes when adding support for `--fix` by iterating until all fixes
+        // were successfully applied. We don't need to do that for suppressions because suppression fixes
+        // should never overlap (and, if they were, the worst outcome is that some suppressions are missing).
+        let FixedCode {
+            source: new_source,
+            source_map,
+        } = apply_fixes(&source, fixes).unwrap_or_else(|fixed| fixed);
+
+        let new_source = source.with_text(new_source, &source_map);
+
+        // Verify that the fix didn't introduce any syntax errors by overriding
+        // the source text for `file`.
+        let mut source_guard = WithUpdatedSourceGuard::new(db, file, &source, new_source.clone());
+        let db = source_guard.db();
+        let new_parsed = parsed_module(db, file);
+        let new_parsed = new_parsed.load(db);
+
+        if new_parsed.has_syntax_errors() {
+            let mut diag = Diagnostic::new(
+                DiagnosticId::InternalError,
+                Severity::Fatal,
+                format_args!(
+                    "Adding suppressions introduced a syntax error. Reverting all changes."
+                ),
+            );
+
+            let mut file_annotation = Annotation::primary(Span::from(file));
+            file_annotation.hide_snippet(true);
+            diag.annotate(file_annotation);
+
+            let parse_diagnostics: Vec<_> = new_parsed
+                .errors()
+                .iter()
+                .map(|error| {
+                    Diagnostic::invalid_syntax(Span::from(file), &error.error, error.location)
+                })
+                .collect();
+
+            diag.add_bug_sub_diagnostics("%5BFix%20error%5D");
+
+            let file_db: &dyn ruff_db::Db = db;
+
+            diag.info(format_args!(
+                "Introduced syntax errors:\n\n{}",
+                DisplayDiagnostics::new(
+                    &file_db,
+                    &DisplayDiagnosticConfig::default(),
+                    &parse_diagnostics
+                )
+            ));
+
+            file_diagnostics.push(diag);
+
+            continue;
+        }
+
+        // Write the changes back to disk.
+        if let Err(err) = write_changes(db, &*system, file, &path, &new_source) {
+            let mut diag = Diagnostic::new(
+                DiagnosticId::Io,
+                Severity::Error,
+                format_args!("Failed to write fixes to file: {err}"),
+            );
+
+            diag.annotate(Annotation::primary(Span::from(file)));
+            diagnostics.push(diag);
+
+            continue;
+        }
+
+        // If we got here then we've been successful. Re-check to get the diagnostics with the
+        // update source, update the fix count.
+
+        if fixable_diagnostics.len() == file_diagnostics.len() {
+            file_diagnostics.clear();
+        } else {
+            // If there are any other file level diagnostics, call `check_file` to re-compute them
+            // with updated ranges.
+            let diagnostics = project.check_file(db, file);
+            *file_diagnostics = diagnostics;
+        }
+
+        fixed_count += fixable_diagnostics.len();
+        // Don't restore the source text or we risk a panic when rendering the diagnostics
+        // if reading any of the fixed files fails (for whatever reason).
+        // The override will get removed on the next `File::sync_path` call.
+        source_guard.defuse();
+    }
+
+    // Stitch the remaining diagnostics back together.
+    diagnostics.extend(by_file.into_values().flatten());
+    diagnostics.sort_by(|left, right| {
+        left.rendering_sort_key(db)
+            .cmp(&right.rendering_sort_key(db))
+    });
+
+    Ok(SuppressAllResult {
+        diagnostics,
+        count: fixed_count,
+    })
+}
+
+fn write_changes(
+    db: &dyn Db,
+    system: &dyn WritableSystem,
+    file: File,
+    path: &SystemPath,
+    new_source: &SourceText,
+) -> Result<(), WriteChangesError> {
+    let metadata = system.path_metadata(path)?;
+
+    if metadata.revision() != file.revision(db) {
+        return Err(WriteChangesError::FileWasModified);
+    }
+
+    system.write_file_bytes(path, &new_source.to_bytes())?;
+
+    Ok(())
+}
+
+#[derive(Debug, Error)]
+enum WriteChangesError {
+    #[error("failed to write changes to disk: {0}")]
+    Io(#[from] std::io::Error),
+
+    #[error("the file has been modified")]
+    FileWasModified,
+}
+
+/// Apply a series of fixes to `File` and returns the updated source code along with the source map.
+///
+/// Returns an error if not all fixes were applied because some fixes are overlapping.
+fn apply_fixes(source: &str, mut fixes: Vec<Fix>) -> Result<FixedCode, FixedCode> {
+    let mut output = String::with_capacity(source.len());
+    let mut last_pos: Option<TextSize> = None;
+    let mut has_overlapping_fixes = false;
+    let mut isolated: FxHashSet<u32> = FxHashSet::default();
+
+    let mut source_map = SourceMap::default();
+
+    fixes.sort_unstable_by_key(Fix::min_start);
+
+    for fix in fixes {
+        let mut edits = fix.edits().iter().peekable();
+
+        // If the fix contains at least one new edit, enforce isolation and positional requirements.
+        if let Some(first) = edits.peek() {
+            // If this fix requires isolation, and we've already applied another fix in the
+            // same isolation group, skip it.
+            if let IsolationLevel::Group(id) = fix.isolation() {
+                if !isolated.insert(id) {
+                    has_overlapping_fixes = true;
+                    continue;
+                }
+            }
+
+            // If this fix overlaps with a fix we've already applied, skip it.
+            if last_pos.is_some_and(|last_pos| last_pos >= first.start()) {
+                has_overlapping_fixes = true;
+                continue;
+            }
+        }
+
+        let mut applied_edits = Vec::with_capacity(fix.edits().len());
+        for edit in edits {
+            // Add all contents from `last_pos` to `fix.location`.
+            let slice = &source[TextRange::new(last_pos.unwrap_or_default(), edit.start())];
+            output.push_str(slice);
+
+            // Add the start source marker for the patch.
+            source_map.push_start_marker(edit, output.text_len());
+
+            // Add the patch itself.
+            output.push_str(edit.content().unwrap_or_default());
+
+            // Add the end source marker for the added patch.
+            source_map.push_end_marker(edit, output.text_len());
+
+            // Track that the edit was applied.
+            last_pos = Some(edit.end());
+            applied_edits.push(edit);
+        }
+    }
+
+    // Add the remaining content.
+    let slice = &source[last_pos.unwrap_or_default().to_usize()..];
+    output.push_str(slice);
+
+    let fixed = FixedCode {
+        source: output,
+        source_map,
+    };
+
+    if has_overlapping_fixes {
+        Err(fixed)
+    } else {
+        Ok(fixed)
+    }
+}
+
+struct FixedCode {
+    /// Source map that allows mapping positions in the fixed code back to positions in the original
+    /// source code (useful for mapping fixed lines back to their original notebook cells).
+    source_map: SourceMap,
+
+    /// The fixed source code
+    source: String,
+}
+
+/// Guard that sets [`File::set_source_text_override`] and guarantees to restore the original source
+/// text unless the guard is explicitly defused.
+struct WithUpdatedSourceGuard<'db> {
+    db: &'db mut dyn Db,
+    file: File,
+    old_source: Option<SourceText>,
+}
+
+impl<'db> WithUpdatedSourceGuard<'db> {
+    fn new(
+        db: &'db mut dyn Db,
+        file: File,
+        old_source: &SourceText,
+        new_source: SourceText,
+    ) -> Self {
+        file.set_source_text_override(db).to(Some(new_source));
+        Self {
+            db,
+            file,
+            old_source: Some(old_source.clone()),
+        }
+    }
+
+    fn defuse(&mut self) {
+        self.old_source = None;
+    }
+
+    fn db(&mut self) -> &mut dyn Db {
+        self.db
+    }
+}
+
+impl Drop for WithUpdatedSourceGuard<'_> {
+    fn drop(&mut self) {
+        if let Some(old_source) = self.old_source.take() {
+            // We don't set `source_text_override` to `None` here because setting the value
+            // invalidates the `source_text` query and there's the chance that reading the file's content
+            // will fail this time (e.g. because the file was deleted), resulting in ty panicking
+            // when trying to render any diagnostic for that file (because all offsets now point nowhere).
+            // The override will be cleared by `File::sync_path`, the next time the revision changes.
+            self.file
+                .set_source_text_override(self.db)
+                .to(Some(old_source));
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use std::collections::hash_map::Entry;
+    use std::hash::{DefaultHasher, Hash, Hasher};
+
+    use insta::assert_snapshot;
+    use ruff_db::cancellation::CancellationTokenSource;
+    use ruff_db::diagnostic::{Diagnostic, DisplayDiagnosticConfig, DisplayDiagnostics};
+    use ruff_db::files::{File, system_path_to_file};
+    use ruff_db::parsed::parsed_module;
+    use ruff_db::source::source_text;
+    use ruff_db::system::{DbWithWritableSystem, SystemPath, SystemPathBuf};
+    use ruff_python_ast::name::Name;
+    use rustc_hash::FxHashMap;
+    use ty_python_semantic::UNUSED_IGNORE_COMMENT;
+    use ty_python_semantic::lint::Level;
+
+    use crate::db::tests::TestDb;
+    use crate::metadata::options::Rules;
+    use crate::metadata::value::RangedValue;
+    use crate::{Db, ProjectMetadata, suppress_all_diagnostics};
+
+    #[test]
+    fn simple_suppression() {
+        assert_snapshot!(
+            suppress_all_in(r#"
+                a = b + 10"#
+        ),
+         @r"
+        Added 1 suppressions
+
+        ## Fixed source
+
+        ```py
+        a = b + 10  # ty:ignore[unresolved-reference]
+        ```
+        ");
+    }
+
+    #[test]
+    fn multiple_suppressions_same_code() {
+        assert_snapshot!(
+            suppress_all_in(r#"
+                a = b + 10 + c"#
+        ),
+         @r"
+        Added 2 suppressions
+
+        ## Fixed source
+
+        ```py
+        a = b + 10 + c  # ty:ignore[unresolved-reference]
+        ```
+        ");
+    }
+
+    #[test]
+    fn multiple_suppressions_different_codes() {
+        assert_snapshot!(
+            suppress_all_in(r#"
+                import sys
+                a = b + 10 + sys.veeersion"#
+        ),
+         @r"
+        Added 2 suppressions
+
+        ## Fixed source
+
+        ```py
+        import sys
+        a = b + 10 + sys.veeersion  # ty:ignore[unresolved-attribute, unresolved-reference]
+        ```
+        ");
+    }
+
+    #[test]
+    fn dont_fix_unused_ignore() {
+        assert_snapshot!(
+            suppress_all_in(r#"
+                import sys
+                a = 5 + 10  # ty: ignore[unresolved-reference]"#
+        ),
+         @r"
+        Added 0 suppressions
+
+        ## Fixed source
+
+        ```py
+        import sys
+        a = 5 + 10  # ty: ignore[unresolved-reference]
+        ```
+
+        ## Diagnostics after applying fixes
+
+        warning[unused-ignore-comment]: Unused `ty: ignore` directive
+         --> test.py:2:13
+          |
+        1 | import sys
+        2 | a = 5 + 10  # ty: ignore[unresolved-reference]
+          |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+          |
+        help: Remove the unused suppression comment
+        ");
+    }
+
+    #[test]
+    fn dont_fix_files_containing_syntax_errors() {
+        assert_snapshot!(
+            suppress_all_in(r#"
+                import sys
+                a = x +
+                "#
+        ),
+         @r"
+        Added 0 suppressions
+
+        ## Fixed source
+
+        ```py
+        import sys
+        a = x +
+        ```
+
+        ## Diagnostics after applying fixes
+
+        error[unresolved-reference]: Name `x` used when not defined
+         --> test.py:2:5
+          |
+        1 | import sys
+        2 | a = x +
+          |     ^
+          |
+        info: rule `unresolved-reference` is enabled by default
+
+        error[invalid-syntax]: Expected an expression
+         --> test.py:2:8
+          |
+        1 | import sys
+        2 | a = x +
+          |        ^
+          |
+        ");
+    }
+
+    #[test]
+    fn arguments() {
+        assert_snapshot!(
+            suppress_all_in(r#"
+                def test(a, b):
+                    pass
+
+
+                test(
+                    a = 10,
+                    c = "unknown"
+                )
+                "#
+        ),
+         @r#"
+        Added 2 suppressions
+
+        ## Fixed source
+
+        ```py
+        def test(a, b):
+            pass
+
+
+        test(
+            a = 10,
+            c = "unknown"  # ty:ignore[unknown-argument]
+        )  # ty:ignore[missing-argument]
+        ```
+        "#);
+    }
+
+    #[test]
+    fn return_type() {
+        assert_snapshot!(
+            suppress_all_in(r#"class A:
+    def test(self, b: int) -> str:
+        return "test"
+
+
+class B(A):
+    def test(
+        self,
+        b: str
+    ) -> A.b:
+        pass"#
+        ),
+         @r#"
+        Added 2 suppressions
+
+        ## Fixed source
+
+        ```py
+        class A:
+            def test(self, b: int) -> str:
+                return "test"
+
+
+        class B(A):
+            def test(
+                self,
+                b: str
+            ) -> A.b:  # ty:ignore[invalid-method-override, unresolved-attribute]
+                pass
+        ```
+        "#);
+    }
+
+    #[test]
+    fn existing_ty_ignore() {
+        assert_snapshot!(
+            suppress_all_in(r#"class A:
+    def test(self, b: int) -> str:
+        return "test"
+
+
+class B(A):
+    def test(  # ty:ignore[unresolved-reference]
+        self,
+        b: str
+    ) -> A.b:
+        pass"#
+        ),
+         @r#"
+        Added 2 suppressions
+
+        ## Fixed source
+
+        ```py
+        class A:
+            def test(self, b: int) -> str:
+                return "test"
+
+
+        class B(A):
+            def test(  # ty:ignore[unresolved-reference, invalid-method-override]
+                self,
+                b: str
+            ) -> A.b:  # ty:ignore[unresolved-attribute]
+                pass
+        ```
+
+        ## Diagnostics after applying fixes
+
+        warning[unused-ignore-comment]: Unused `ty: ignore` directive: 'unresolved-reference'
+         --> test.py:7:28
+          |
+        6 | class B(A):
+        7 |     def test(  # ty:ignore[unresolved-reference, invalid-method-override]
+          |                            ^^^^^^^^^^^^^^^^^^^^
+        8 |         self,
+        9 |         b: str
+          |
+        help: Remove the unused suppression code
+        "#);
+    }
+
+    #[track_caller]
+    fn suppress_all_in(source: &str) -> String {
+        use std::fmt::Write as _;
+
+        let mut metadata = ProjectMetadata::new(Name::new_static("test"), SystemPathBuf::from("."));
+        metadata.options.rules = Some(Rules::from_iter([(
+            RangedValue::cli(UNUSED_IGNORE_COMMENT.name.to_string()),
+            RangedValue::cli(Level::Warn),
+        )]));
+
+        let mut db = TestDb::new(metadata);
+        db.init_program().unwrap();
+
+        db.write_file(
+            "test.py",
+            ruff_python_trivia::textwrap::dedent(source).trim(),
+        )
+        .unwrap();
+
+        let file = system_path_to_file(&db, "test.py").unwrap();
+
+        let parsed_before = parsed_module(&db, file);
+        let had_syntax_errors = parsed_before.load(&db).has_syntax_errors();
+
+        let diagnostics = db.project().check_file(&db, file);
+        let total_diagnostics = diagnostics.len();
+        let cancellation_token_source = CancellationTokenSource::new();
+        let fixes =
+            suppress_all_diagnostics(&mut db, diagnostics, &cancellation_token_source.token())
+                .expect("operation never gets cancelled");
+
+        assert_eq!(fixes.count, total_diagnostics - fixes.diagnostics.len());
+
+        File::sync_path(&mut db, SystemPath::new("test.py"));
+
+        let fixed = source_text(&db, file);
+
+        let parsed = parsed_module(&db, file);
+        let parsed = parsed.load(&db);
+
+        let diagnostics_after_applying_fixes = db.project().check_file(&db, file);
+
+        let mut output = String::new();
+
+        writeln!(
+            output,
+            "Added {} suppressions\n\n## Fixed source\n\n```py\n{}\n```\n",
+            fixes.count,
+            fixed.as_str()
+        )
+        .unwrap();
+
+        if !fixes.diagnostics.is_empty() {
+            writeln!(
+                output,
+                "## Diagnostics after applying fixes\n\n{diagnostics}\n",
+                diagnostics = DisplayDiagnostics::new(
+                    &db,
+                    &DisplayDiagnosticConfig::default(),
+                    &fixes.diagnostics
+                )
+            )
+            .unwrap();
+        }
+
+        assert!(
+            !parsed.has_syntax_errors() || had_syntax_errors,
+            "Fixed introduced syntax errors\n\n{output}"
+        );
+
+        let new_diagnostics =
+            diff_diagnostics(&fixes.diagnostics, &diagnostics_after_applying_fixes);
+
+        if !new_diagnostics.is_empty() {
+            writeln!(
+                &mut output,
+                "## New diagnostics after re-checking file\n\n{diagnostics}\n",
+                diagnostics = DisplayDiagnostics::new(
+                    &db,
+                    &DisplayDiagnosticConfig::default(),
+                    &new_diagnostics
+                )
+            )
+            .unwrap();
+        }
+
+        output
+    }
+
+    fn diff_diagnostics<'a>(before: &'a [Diagnostic], after: &'a [Diagnostic]) -> Vec<Diagnostic> {
+        let before = DiagnosticFingerprint::group_diagnostics(before);
+        let after = DiagnosticFingerprint::group_diagnostics(after);
+
+        after
+            .into_iter()
+            .filter(|(key, _)| !before.contains_key(key))
+            .map(|(_, diagnostic)| diagnostic.clone())
+            .collect()
+    }
+
+    #[derive(Copy, Clone, Eq, PartialEq, Hash)]
+    struct DiagnosticFingerprint(u64);
+
+    impl DiagnosticFingerprint {
+        fn group_diagnostics(diagnostics: &[Diagnostic]) -> FxHashMap<Self, &Diagnostic> {
+            let mut result = FxHashMap::default();
+
+            for diagnostic in diagnostics {
+                Self::from_diagnostic(diagnostic, &mut result);
+            }
+
+            result
+        }
+
+        fn from_diagnostic<'a>(
+            diagnostic: &'a Diagnostic,
+            seen: &mut FxHashMap<DiagnosticFingerprint, &'a Diagnostic>,
+        ) -> DiagnosticFingerprint {
+            let mut disambiguator = 0u64;
+
+            loop {
+                let mut h = DefaultHasher::default();
+                disambiguator.hash(&mut h);
+
+                diagnostic.id().hash(&mut h);
+
+                let key = DiagnosticFingerprint(h.finish());
+                match seen.entry(key) {
+                    Entry::Occupied(_) => {
+                        disambiguator += 1;
+                    }
+                    Entry::Vacant(entry) => {
+                        entry.insert(diagnostic);
+                        return key;
+                    }
+                }
+            }
+        }
+    }
+}

crates/ty_project/src/glob.rs

@@ -1,5 +1,6 @@
 use ruff_db::system::SystemPath;
 
+use crate::glob::include::MatchFile;
 pub(crate) use exclude::{ExcludeFilter, ExcludeFilterBuilder};
 pub(crate) use include::{IncludeFilter, IncludeFilterBuilder};
 pub(crate) use portable::{
@@ -39,7 +40,9 @@ impl IncludeExcludeFilter {
         if self.exclude.match_directory(path, mode) {
             IncludeResult::Excluded
         } else if self.include.match_directory(path) {
-            IncludeResult::Included
+            IncludeResult::Included {
+                literal_match: None,
+            }
         } else {
             IncludeResult::NotIncluded
         }
@@ -52,10 +55,16 @@ impl IncludeExcludeFilter {
     ) -> IncludeResult {
         if self.exclude.match_file(path, mode) {
             IncludeResult::Excluded
-        } else if self.include.match_file(path) {
-            IncludeResult::Included
         } else {
-            IncludeResult::NotIncluded
+            match self.include.match_file(path) {
+                MatchFile::Literal => IncludeResult::Included {
+                    literal_match: Some(true),
+                },
+                MatchFile::Pattern => IncludeResult::Included {
+                    literal_match: Some(false),
+                },
+                MatchFile::No => IncludeResult::NotIncluded,
+            }
         }
     }
 }
@@ -86,7 +95,7 @@ pub(crate) enum IncludeResult {
     ///
     /// For directories: This isn't a guarantee that any file in this directory gets included
     /// but we need to traverse it to make this decision.
-    Included,
+    Included { literal_match: Option<bool> },
 
     /// The path matches an exclude pattern.
     Excluded,

crates/ty_project/src/glob/include.rs

@@ -33,7 +33,8 @@ const DFA_SIZE_LIMIT: usize = 1_000_000;
 pub(crate) struct IncludeFilter {
     #[get_size(ignore)]
     glob_set: GlobSet,
-    original_patterns: Box<[String]>,
+    original_patterns: Box<[Box<str>]>,
+    literal_pattern_indices: Box<[usize]>,
     #[get_size(size_fn = dfa_memory_usage)]
     dfa: Option<dfa::dense::DFA<Vec<u32>>>,
 }
@@ -45,10 +46,29 @@ fn dfa_memory_usage(dfa: &Option<dfa::dense::DFA<Vec<u32>>>) -> usize {
 
 impl IncludeFilter {
     /// Whether the file matches any of the globs.
-    pub(crate) fn match_file(&self, path: impl AsRef<SystemPath>) -> bool {
+    pub(crate) fn match_file(&self, path: impl AsRef<SystemPath>) -> MatchFile {
         let path = path.as_ref();
 
-        self.glob_set.is_match(path)
+        if self.literal_pattern_indices.is_empty() {
+            return if self.glob_set.is_match(path) {
+                MatchFile::Pattern
+            } else {
+                MatchFile::No
+            };
+        }
+
+        let matches = self.glob_set.matches(path);
+
+        if matches.is_empty() {
+            MatchFile::No
+        } else {
+            for match_index in matches {
+                if self.literal_pattern_indices.contains(&match_index) {
+                    return MatchFile::Literal;
+                }
+            }
+            MatchFile::Pattern
+        }
     }
 
     /// Check whether a directory or any of its children can be matched by any of the globs.
@@ -120,18 +140,36 @@ impl PartialEq for IncludeFilter {
 
 impl Eq for IncludeFilter {}
 
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+pub(crate) enum MatchFile {
+    No,
+    /// The file path matches the glob literally exactly. This is only the case for globs
+    /// that don't use any wildcards.
+    Literal,
+
+    /// The file path matches the glob pattern.
+    Pattern,
+}
+
+impl MatchFile {}
+
 #[derive(Debug)]
 pub(crate) struct IncludeFilterBuilder {
     set: GlobSetBuilder,
-    original_pattern: Vec<String>,
+    set_len: usize,
+    original_patterns: Vec<Box<str>>,
     regexes: Vec<String>,
+    /// Indices of literal patterns (contain no meta characters).
+    literal_pattern_indices: Vec<usize>,
 }
 
 impl IncludeFilterBuilder {
     pub(crate) fn new() -> Self {
         Self {
+            literal_pattern_indices: Vec::new(),
             set: GlobSetBuilder::new(),
-            original_pattern: Vec::new(),
+            set_len: 0,
+            original_patterns: Vec::new(),
             regexes: Vec::new(),
         }
     }
@@ -161,13 +199,16 @@ impl IncludeFilterBuilder {
             // No need to support Windows-style paths, so the backslash can be used a escape.
             .backslash_escape(true)
             .build()?;
-        self.original_pattern.push(input.relative().to_string());
+
+        let is_literal_pattern = globset::escape(glob_pattern) == glob_pattern;
+
+        self.original_patterns.push(input.relative().into());
 
         // `lib` is the same as `lib/**`
         // Add a glob that matches `lib` exactly, change the glob to `lib/**`.
         if glob_pattern.ends_with("**") {
             self.push_prefix_regex(&glob);
-            self.set.add(glob);
+            self.add_glob(glob);
         } else {
             let prefix_glob = GlobBuilder::new(&format!("{glob_pattern}/**"))
                 .literal_separator(true)
@@ -176,19 +217,28 @@ impl IncludeFilterBuilder {
                 .build()?;
 
             self.push_prefix_regex(&prefix_glob);
-            self.set.add(prefix_glob);
+            self.add_glob(prefix_glob);
 
             // The reason we add the exact glob, e.g. `src` when the original pattern was `src/` is
             // so that `match_file` returns true when matching against a file. However, we don't
             // need to do this if this is a pattern that should only match a directory (specifically, its contents).
             if !only_directory {
-                self.set.add(glob);
+                if is_literal_pattern {
+                    self.literal_pattern_indices.push(self.set_len);
+                }
+
+                self.add_glob(glob);
             }
         }
 
         Ok(self)
     }
 
+    fn add_glob(&mut self, glob: Glob) {
+        self.set.add(glob);
+        self.set_len += 1;
+    }
+
     fn push_prefix_regex(&mut self, glob: &Glob) {
         let main_separator = regex::escape(MAIN_SEPARATOR_STR);
 
@@ -239,7 +289,8 @@ impl IncludeFilterBuilder {
         Ok(IncludeFilter {
             glob_set,
             dfa,
-            original_patterns: self.original_pattern.into(),
+            literal_pattern_indices: self.literal_pattern_indices.into(),
+            original_patterns: self.original_patterns.into(),
         })
     }
 }
@@ -248,7 +299,7 @@ impl IncludeFilterBuilder {
 mod tests {
     use std::path::{MAIN_SEPARATOR, MAIN_SEPARATOR_STR};
 
-    use crate::glob::include::{IncludeFilter, IncludeFilterBuilder};
+    use crate::glob::include::{IncludeFilter, IncludeFilterBuilder, MatchFile};
     use crate::glob::{PortableGlobKind, PortableGlobPattern};
     use ruff_db::system::{MemoryFileSystem, walk_directory::WalkState};
 
@@ -326,33 +377,33 @@ mod tests {
             "files/*.py",
         ]);
 
-        assert!(filter.match_file("lib"));
-        assert!(filter.match_file("lib/more/test"));
+        assert_eq!(filter.match_file("lib"), MatchFile::Literal);
+        assert_eq!(filter.match_file("lib/more/test"), MatchFile::Pattern);
 
         // Unlike `directory`, `directory/` only includes a directory with the given name and its contents
-        assert!(!filter.match_file("directory"));
-        assert!(filter.match_file("directory/more/test"));
+        assert_eq!(filter.match_file("directory"), MatchFile::No);
+        assert_eq!(filter.match_file("directory/more/test"), MatchFile::Pattern);
 
         // Unlike `src`, `src/*` only includes a directory with the given name.
-        assert!(!filter.match_file("src"));
-        assert!(filter.match_file("src/more/test"));
+        assert_eq!(filter.match_file("src"), MatchFile::No);
+        assert_eq!(filter.match_file("src/more/test"), MatchFile::Pattern);
 
         // Unlike `tests`, `tests/**` only includes files under `tests`, but not a file named tests
-        assert!(!filter.match_file("tests"));
-        assert!(filter.match_file("tests/more/test"));
+        assert_eq!(filter.match_file("tests"), MatchFile::No);
+        assert_eq!(filter.match_file("tests/more/test"), MatchFile::Pattern);
 
         // Unlike `match_directory`, prefixes should not be included.
-        assert!(!filter.match_file("a"));
-        assert!(!filter.match_file("a/test-b"));
+        assert_eq!(filter.match_file("a"), MatchFile::No);
+        assert_eq!(filter.match_file("a/test-b"), MatchFile::No);
 
-        assert!(!filter.match_file("a/test-b/x"));
-        assert!(!filter.match_file("a/test"));
+        assert_eq!(filter.match_file("a/test-b/x"), MatchFile::No);
+        assert_eq!(filter.match_file("a/test"), MatchFile::No);
 
-        assert!(filter.match_file("files/a.py"));
-        assert!(filter.match_file("files/a.py/bcd"));
+        assert_eq!(filter.match_file("files/a.py"), MatchFile::Pattern);
+        assert_eq!(filter.match_file("files/a.py/bcd"), MatchFile::Pattern);
 
-        assert!(!filter.match_file("not_included"));
-        assert!(!filter.match_file("files/a.pi"));
+        assert_eq!(filter.match_file("not_included"), MatchFile::No);
+        assert_eq!(filter.match_file("files/a.pi"), MatchFile::No);
     }
 
     /// Check that we skip directories that can never match.

crates/ty_project/src/lib.rs

@@ -9,6 +9,7 @@ use crate::walk::{ProjectFilesFilter, ProjectFilesWalker};
 pub use db::tests::TestDb;
 pub use db::{ChangeResult, CheckMode, Db, ProjectDatabase, SalsaMemoryDump};
 use files::{Index, Indexed, IndexedFiles};
+pub use fixes::suppress_all_diagnostics;
 use metadata::settings::Settings;
 pub use metadata::{ProjectMetadata, ProjectMetadataError};
 use ruff_db::diagnostic::{
@@ -33,6 +34,7 @@ use ty_python_semantic::types::check_types;
 
 mod db;
 mod files;
+mod fixes;
 mod glob;
 pub mod metadata;
 mod walk;
@@ -214,15 +216,19 @@ impl Project {
     /// This means, that this method is an over-approximation of `Self::files` and may return `true` for paths
     /// that won't be included when checking the project because they're ignored in a `.gitignore` file.
     pub fn is_file_included(self, db: &dyn Db, path: &SystemPath) -> bool {
-        ProjectFilesFilter::from_project(db, self)
-            .is_file_included(path, GlobFilterCheckMode::Adhoc)
-            == IncludeResult::Included
+        matches!(
+            ProjectFilesFilter::from_project(db, self)
+                .is_file_included(path, GlobFilterCheckMode::Adhoc),
+            IncludeResult::Included { .. }
+        )
     }
 
     pub fn is_directory_included(self, db: &dyn Db, path: &SystemPath) -> bool {
-        ProjectFilesFilter::from_project(db, self)
-            .is_directory_included(path, GlobFilterCheckMode::Adhoc)
-            == IncludeResult::Included
+        matches!(
+            ProjectFilesFilter::from_project(db, self)
+                .is_directory_included(path, GlobFilterCheckMode::Adhoc),
+            IncludeResult::Included { .. }
+        )
     }
 
     pub fn reload(self, db: &mut dyn Db, metadata: ProjectMetadata) {
@@ -694,38 +700,7 @@ where
         Err(error) => {
             let message = error.to_diagnostic_message(Some(file.path(db)));
             let mut diagnostic = Diagnostic::new(DiagnosticId::Panic, Severity::Fatal, message);
-            diagnostic.sub(SubDiagnostic::new(
-                SubDiagnosticSeverity::Info,
-                "This indicates a bug in ty.",
-            ));
-
-            let report_message = "If you could open an issue at https://github.com/astral-sh/ty/issues/new?title=%5Bpanic%5D, we'd be very appreciative!";
-            diagnostic.sub(SubDiagnostic::new(
-                SubDiagnosticSeverity::Info,
-                report_message,
-            ));
-            diagnostic.sub(SubDiagnostic::new(
-                SubDiagnosticSeverity::Info,
-                format!(
-                    "Platform: {os} {arch}",
-                    os = std::env::consts::OS,
-                    arch = std::env::consts::ARCH
-                ),
-            ));
-            if let Some(version) = ruff_db::program_version() {
-                diagnostic.sub(SubDiagnostic::new(
-                    SubDiagnosticSeverity::Info,
-                    format!("Version: {version}"),
-                ));
-            }
-
-            diagnostic.sub(SubDiagnostic::new(
-                SubDiagnosticSeverity::Info,
-                format!(
-                    "Args: {args:?}",
-                    args = std::env::args().collect::<Vec<_>>()
-                ),
-            ));
+            diagnostic.add_bug_sub_diagnostics("%5Bpanic%5D");
 
             if let Some(backtrace) = error.backtrace {
                 match backtrace.status() {

crates/ty_project/src/metadata/options.rs

@@ -850,7 +850,6 @@ impl SrcOptions {
 )]
 #[serde(rename_all = "kebab-case", transparent)]
 pub struct Rules {
-    #[get_size(ignore)] // TODO: Add `GetSize` support for `OrderMap`.
     inner: OrderMap<RangedValue<String>, RangedValue<Level>, BuildHasherDefault<FxHasher>>,
 }
 

crates/ty_project/src/metadata/settings.rs

@@ -97,7 +97,7 @@ impl Override {
         matches!(
             self.files
                 .is_file_included(path, GlobFilterCheckMode::Adhoc),
-            IncludeResult::Included
+            IncludeResult::Included { .. }
         )
     }
 }

crates/ty_project/src/walk.rs

@@ -79,7 +79,9 @@ impl<'a> ProjectFilesFilter<'a> {
         match self.match_included_paths(path, mode) {
             None => IncludeResult::NotIncluded,
             Some(CheckPathMatch::Partial) => self.src_filter.is_file_included(path, mode),
-            Some(CheckPathMatch::Full) => IncludeResult::Included,
+            Some(CheckPathMatch::Full) => IncludeResult::Included {
+                literal_match: Some(true),
+            },
         }
     }
 
@@ -93,7 +95,9 @@ impl<'a> ProjectFilesFilter<'a> {
             Some(CheckPathMatch::Partial) => {
                 self.src_filter.is_directory_maybe_included(path, mode)
             }
-            Some(CheckPathMatch::Full) => IncludeResult::Included,
+            Some(CheckPathMatch::Full) => IncludeResult::Included {
+                literal_match: Some(true),
+            },
         }
     }
 }
@@ -189,60 +193,59 @@ impl<'a> ProjectFilesWalker<'a> {
                                 let directory_included = filter
                                     .is_directory_included(entry.path(), GlobFilterCheckMode::TopDown);
                                 return match directory_included {
-                                    IncludeResult::Included => WalkState::Continue,
+                                    IncludeResult::Included { .. } => WalkState::Continue,
                                     IncludeResult::Excluded => {
                                         tracing::debug!(
                                             "Skipping directory '{path}' because it is excluded by a default or `src.exclude` pattern",
                                             path=entry.path()
                                         );
                                         WalkState::Skip
-                                    },
+                                    }
                                     IncludeResult::NotIncluded => {
                                         tracing::debug!(
                                             "Skipping directory `{path}` because it doesn't match any `src.include` pattern or path specified on the CLI",
                                             path=entry.path()
                                         );
                                         WalkState::Skip
-                                    },
+                                    }
                                 };
                             }
                         } else {
-                            // Ignore any non python files to avoid creating too many entries in `Files`.
-                            // Unless the file is explicitly passed, we then always assume it's a python file.
-                            let source_type = entry.path().extension().and_then(PySourceType::try_from_extension).or_else(|| {
-                                if entry.depth() == 0 {
-                                    Some(PySourceType::Python)
-                                } else {
-                                    db.system().source_type(entry.path())
-                                }
-                            });
-
-                            if source_type.is_none()
-                            {
-                                return WalkState::Continue;
-                            }
-
                             // For all files, except the ones that were explicitly passed to the walker (CLI),
                             // check if they're included in the project.
                             if entry.depth() > 0 || self.force_exclude {
                                 match filter
                                     .is_file_included(entry.path(), GlobFilterCheckMode::TopDown)
                                 {
-                                    IncludeResult::Included => {},
+                                    IncludeResult::Included { literal_match } => {
+                                        // Ignore any non python files to avoid creating too many entries in `Files`.
+                                        // Unless the file is explicitly passed on the CLI or a literal match in the `include`, we then always assume it's a file ty can analyze
+                                        let source_type = if literal_match == Some(true) || entry.depth() == 0 {
+                                            Some(PySourceType::Python)
+                                        } else {
+                                            entry.path().extension().and_then(PySourceType::try_from_extension).or_else(|| db.system().source_type(entry.path()))
+                                        };
+
+
+                                        if source_type.is_none()
+                                        {
+                                            return WalkState::Continue;
+                                        }
+                                    }
                                     IncludeResult::Excluded => {
                                         tracing::debug!(
                                             "Ignoring file `{path}` because it is excluded by a default or `src.exclude` pattern.",
                                             path=entry.path()
                                         );
                                         return WalkState::Continue;
-                                    },
+                                    }
                                     IncludeResult::NotIncluded => {
                                         tracing::debug!(
                                             "Ignoring file `{path}` because it doesn't match any `src.include` pattern or path specified on the CLI.",
                                             path=entry.path()
                                         );
                                         return WalkState::Continue;
-                                    },
+                                    }
                                 }
                             }
 

crates/ty_python_semantic/resources/mdtest/annotations/new_types.md

@@ -168,6 +168,56 @@ on top of that:
 Foo = NewType("Foo", 42)
 ```
 
+## `NewType`s in arithmetic and comparison expressions might or might not act as their base
+
+These expressions are valid because `Foo` acts as its base type, `int`:
+
+```py
+from typing import NewType
+
+Foo = NewType("Foo", int)
+
+reveal_type(Foo(42) + 1)  # revealed: int
+reveal_type(1 + Foo(42))  # revealed: int
+reveal_type(Foo(42) + Foo(42))  # revealed: int
+reveal_type(Foo(42) == 42)  # revealed: bool
+reveal_type(42 == Foo(42))  # revealed: bool
+reveal_type(Foo(42) == Foo(42))  # revealed: bool
+```
+
+However, we can't always substitute `int` for `Foo` to evaluate expressions like these. In the
+following cases, only `Foo` itself is valid:
+
+```py
+class Bar:
+    def __add__(self, other: Foo) -> Foo:
+        return other
+
+    def __radd__(self, other: Foo) -> Foo:
+        return other
+
+    def __lt__(self, other: Foo) -> bool:
+        return True
+
+    def __gt__(self, other: Foo) -> bool:
+        return True
+
+    def __contains__(self, key: Foo) -> bool:
+        return True
+
+reveal_type(Foo(42) + Bar())  # revealed: Foo
+reveal_type(Bar() + Foo(42))  # revealed: Foo
+reveal_type(Foo(42) < Bar())  # revealed: bool
+reveal_type(Bar() < Foo(42))  # revealed: bool
+reveal_type(Foo(42) in Bar())  # revealed: bool
+
+42 + Bar()  # error: [unsupported-operator]
+Bar() + 42  # error: [unsupported-operator]
+42 < Bar()  # error: [unsupported-operator]
+Bar() < 42  # error: [unsupported-operator]
+42 in Bar()  # error: [unsupported-operator]
+```
+
 ## `float` and `complex` special cases
 
 `float` and `complex` are subject to a special case in the typing spec, which we currently interpret
@@ -178,6 +228,7 @@ and we accept the unions they expand into.
 
 ```py
 from typing import NewType
+from ty_extensions import static_assert, is_assignable_to
 
 Foo = NewType("Foo", float)
 Foo(3.14)
@@ -186,6 +237,15 @@ Foo("hello")  # error: [invalid-argument-type] "Argument is incorrect: Expected
 
 reveal_type(Foo(3.14).__class__)  # revealed: type[int] | type[float]
 reveal_type(Foo(42).__class__)  # revealed: type[int] | type[float]
+static_assert(is_assignable_to(Foo, float))
+static_assert(is_assignable_to(Foo, int | float))
+static_assert(is_assignable_to(Foo, int | float | None))
+# The assignments above require treating `Foo` as its underlying union type. Each of its members is
+# assignable to the union on the right, so `Foo` is assignable to the union, even though `Foo` as a
+# whole isn't assignable to any one member. However, as in the previous section, we need to be sure
+# that this treatment doesn't break cases like the assignment below, where `Foo` *is* assignable to
+# the union on the right, even though its members *aren't*.
+static_assert(is_assignable_to(Foo, Foo | None))
 
 Bar = NewType("Bar", complex)
 Bar(1 + 2j)
@@ -196,6 +256,11 @@ Bar("goodbye")  # error: [invalid-argument-type]
 reveal_type(Bar(1 + 2j).__class__)  # revealed: type[int] | type[float] | type[complex]
 reveal_type(Bar(3.14).__class__)  # revealed: type[int] | type[float] | type[complex]
 reveal_type(Bar(42).__class__)  # revealed: type[int] | type[float] | type[complex]
+static_assert(is_assignable_to(Bar, complex))
+static_assert(is_assignable_to(Bar, int | float | complex))
+static_assert(is_assignable_to(Bar, int | float | complex | None))
+# See the `Foo | None` case above.
+static_assert(is_assignable_to(Bar, Bar | None))
 ```
 
 We don't currently try to distinguish between an implicit union (e.g. `float`) and the equivalent
@@ -223,6 +288,52 @@ def g(_: Callable[[int | float | complex], Bar]): ...
 g(Bar)
 ```
 
+The arithmetic and comparison test cases in the previous section used a `NewType` of `int`, but
+`NewType`s of `float` and `complex` are more complicated, because their base type is a union, and
+that union needs special handling in binary expressions. In these examples, we we need to lower
+`Foo` to `int | float` and then check each member of that union _individually_, as we would with an
+explicit `Union` on the left side:
+
+```py
+reveal_type(Foo(3.14) < Foo(42))  # revealed: bool
+reveal_type(Foo(3.14) == Foo(42))  # revealed: bool
+reveal_type(Foo(3.14) + Foo(42))  # revealed: int | float
+reveal_type(Foo(3.14) / Foo(42))  # revealed: int | float
+```
+
+But again as above, we can't _always_ lower `Foo` to `int | float`, because there are also binary
+expressions where only `Foo` itself is valid:
+
+```py
+class Bing:
+    def __add__(self, other: Foo) -> Foo:
+        return other
+
+    def __radd__(self, other: Foo) -> Foo:
+        return other
+
+    def __lt__(self, other: Foo) -> bool:
+        return True
+
+    def __gt__(self, other: Foo) -> bool:
+        return True
+
+    def __contains__(self, key: Foo) -> bool:
+        return True
+
+reveal_type(Foo(3.14) + Bing())  # revealed: Foo
+reveal_type(Bing() + Foo(42))  # revealed: Foo
+reveal_type(Foo(3.14) < Bing())  # revealed: bool
+reveal_type(Bing() < Foo(42))  # revealed: bool
+reveal_type(Foo(3.14) in Bing())  # revealed: bool
+
+3.14 + Bing()  # error: [unsupported-operator]
+Bing() + 3.14  # error: [unsupported-operator]
+3.14 < Bing()  # error: [unsupported-operator]
+Bing() < 3.14  # error: [unsupported-operator]
+3.14 in Bing()  # error: [unsupported-operator]
+```
+
 ## A `NewType` definition must be a simple variable assignment
 
 ```py

crates/ty_python_semantic/resources/mdtest/comparison/tuples.md

@@ -338,7 +338,111 @@ reveal_type(a is not c)  # revealed: Literal[True]
 
 For tuples like `tuple[int, ...]`, `tuple[Any, ...]`
 
-// TODO
+### Unsupported Comparisons
+
+<!-- snapshot-diagnostics -->
+
+Comparisons between homogeneous tuples with incompatible element types should emit diagnostics for
+ordering operators (`<`, `<=`, `>`, `>=`), but not for equality operators (`==`, `!=`).
+
+```py
+def f(
+    a: tuple[int, ...],
+    b: tuple[str, ...],
+    c: tuple[str],
+):
+    # Equality comparisons are always valid
+    reveal_type(a == b)  # revealed: bool
+    reveal_type(a != b)  # revealed: bool
+
+    # Ordering comparisons between incompatible types should emit errors
+    # error: [unsupported-operator] "Operator `<` is not supported between objects of type `tuple[int, ...]` and `tuple[str, ...]`"
+    a < b
+    # error: [unsupported-operator] "Operator `<` is not supported between objects of type `tuple[str, ...]` and `tuple[int, ...]`"
+    b < a
+    # error: [unsupported-operator] "Operator `<` is not supported between objects of type `tuple[int, ...]` and `tuple[str]`"
+    a < c
+    # error: [unsupported-operator] "Operator `<` is not supported between objects of type `tuple[str]` and `tuple[int, ...]`"
+    c < a
+```
+
+When comparing fixed-length tuples with variable-length tuples, all element types that could
+potentially be compared must be compatible.
+
+```py
+def _(
+    var_int: tuple[int, ...],
+    var_str: tuple[str, ...],
+    fixed_int_str: tuple[int, str],
+):
+    # Fixed `tuple[int, str]` vs. variable `tuple[int, ...]`:
+    # Position 0: `int` vs. `int` are comparable.
+    # Position 1 (if `var_int` has 2+ elements): `str` vs. `int` are not comparable.
+    # error: [unsupported-operator]
+    fixed_int_str < var_int
+
+    # Variable `tuple[int, ...]` vs. fixed `tuple[int, str]`:
+    # Position 0: `int` vs. `int` are comparable.
+    # Position 1 (if `var_int` has 2+ elements): `int` vs. `str` are not comparable.
+    # error: [unsupported-operator]
+    var_int < fixed_int_str
+
+    # Variable `tuple[str, ...]` vs. fixed `tuple[int, str]`:
+    # Position 0: `str` vs. `int` are not comparable.
+    # error: [unsupported-operator]
+    var_str < fixed_int_str
+```
+
+### Supported Comparisons
+
+Comparisons between homogeneous tuples with compatible element types should work.
+
+```py
+def _(a: tuple[int, ...], b: tuple[int, ...], c: tuple[bool, ...]):
+    # Same element types - always valid
+    reveal_type(a == b)  # revealed: bool
+    reveal_type(a != b)  # revealed: bool
+    reveal_type(a < b)  # revealed: bool
+    reveal_type(a <= b)  # revealed: bool
+    reveal_type(a > b)  # revealed: bool
+    reveal_type(a >= b)  # revealed: bool
+
+    # int and bool are compatible for comparison
+    reveal_type(a < c)  # revealed: bool
+    reveal_type(c < a)  # revealed: bool
+```
+
+### Tuples with Prefixes and Suffixes
+
+<!-- snapshot-diagnostics -->
+
+Variable-length tuples with prefixes and suffixes are also checked.
+
+```toml
+[environment]
+python-version = "3.11"
+```
+
+```py
+def _(
+    prefix_int_var_str: tuple[int, *tuple[str, ...]],
+    prefix_str_var_int: tuple[str, *tuple[int, ...]],
+):
+    # Prefix `int` vs. prefix `str` are not comparable.
+    # error: [unsupported-operator]
+    prefix_int_var_str < prefix_str_var_int
+```
+
+Tuples with compatible prefixes/suffixes are allowed.
+
+```py
+def _(
+    prefix_int_var_int: tuple[int, *tuple[int, ...]],
+    prefix_int_var_bool: tuple[int, *tuple[bool, ...]],
+):
+    # Prefix `int` vs. prefix `int`, variable `int` vs. variable `bool` are all comparable.
+    reveal_type(prefix_int_var_int < prefix_int_var_bool)  # revealed: bool
+```
 
 ## Chained comparisons with elements that incorrectly implement `__bool__`
 

crates/ty_python_semantic/resources/mdtest/dataclasses/dataclasses.md

@@ -583,7 +583,7 @@ from module import NotFrozenBase
 
 @final
 @dataclass(frozen=True)
-@total_ordering
+@total_ordering  # error: [invalid-total-ordering]
 class FrozenChild(NotFrozenBase):  # error: [invalid-frozen-dataclass-subclass]
     y: str
 ```