[ty] Always infer the submodule literal for submodule attribute-access, even when we emit a diagnostic

## Summary

Derived from #17371

Fixes astral-sh/ty#256
Fixes https://github.com/astral-sh/ty/issues/1415
Fixes https://github.com/astral-sh/ty/issues/1433
Fixes https://github.com/astral-sh/ty/issues/1524

Properly handles any kind of recursive inference and prevents panics.

---

Let me explain techniques for converging fixed-point iterations during
recursive type inference.
There are two types of type inference that naively don't converge
(causing salsa to panic): divergent type inference and oscillating type
inference.

### Divergent type inference

Divergent type inference occurs when eagerly expanding a recursive type.
A typical example is this:

```python
class C:
    def f(self, other: "C"):
        self.x = (other.x, 1)

reveal_type(C().x) # revealed: Unknown | tuple[Unknown | tuple[Unknown | tuple[..., Literal[1]], Literal[1]], Literal[1]]
```

To solve this problem, we have already introduced `Divergent` types
(https://github.com/astral-sh/ruff/pull/20312). `Divergent` types are
treated as a kind of dynamic type [^1].

```python
Unknown | tuple[Unknown | tuple[Unknown | tuple[..., Literal[1]], Literal[1]], Literal[1]]
=> Unknown | tuple[Divergent, Literal[1]]
```

When a query function that returns a type enters a cycle, it sets
`Divergent` as the cycle initial value (instead of `Never`). Then, in
the cycle recovery function, it reduces the nesting of types containing
`Divergent` to converge.

```python
0th: Divergent
1st: Unknown | tuple[Divergent, Literal[1]]
2nd: Unknown | tuple[Unknown | tuple[Divergent, Literal[1]], Literal[1]]
=> Unknown | tuple[Divergent, Literal[1]]
```

Each cycle recovery function for each query should operate only on the
`Divergent` type originating from that query.
For this reason, while `Divergent` appears the same as `Any` to the
user, it internally carries some information: the location where the
cycle occurred. Previously, we roughly identified this by having the
scope where the cycle occurred, but with the update to salsa, functions
that create cycle initial values ​​can now receive a `salsa::Id`
(https://github.com/salsa-rs/salsa/pull/1012). This is an opaque ID that
uniquely identifies the cycle head (the query that is the starting point
for the fixed-point iteration). `Divergent` now has this `salsa::Id`.

### Oscillating type inference

Now, another thing to consider is oscillating type inference.
Oscillating type inference arises from the fact that monotonicity is
broken. Monotonicity here means that for a query function, if it enters
a cycle, the calculation must start from a "bottom value" and progress
towards the final result with each cycle. Monotonicity breaks down in
type systems that have features like overloading and overriding.

```python
class Base:
    def flip(self) -> "Sub":
        return Sub()

class Sub(Base):
    def flip(self) -> "Base":
        return Base()

class C:
    def __init__(self, x: Sub):
        self.x = x

    def replace_with(self, other: "C"):
        self.x = other.x.flip()

reveal_type(C(Sub()).x)
```

Naive fixed-point iteration results in `Divergent -> Sub -> Base -> Sub
-> ...`, which oscillates forever without diverging or converging. To
address this, the salsa API has been modified so that the cycle recovery
function receives the value of the previous cycle
(https://github.com/salsa-rs/salsa/pull/1012).
The cycle recovery function returns the union type of the current cycle
and the previous cycle. In the above example, the result type for each
cycle is `Divergent -> Sub -> Base (= Sub | Base) -> Base`, which
converges.

The final result of oscillating type inference does not contain
`Divergent` because `Divergent` that appears in a union type can be
removed, as is clear from the expansion. This simplification is
performed at the same time as nesting reduction.

```
T | Divergent = T | (T | (T | ...)) = T
```

[^1]: In theory, it may be possible to strictly treat types containing
`Divergent` types as recursive types, but we probably shouldn't go that
deep yet. (AFAIK, there are no PEPs that specify how to handle
implicitly recursive types that aren't named by type aliases)

## Performance analysis

A happy side effect of this PR is that we've observed widespread
performance improvements!
This is likely due to the removal of the `ITERATIONS_BEFORE_FALLBACK`
and max-specialization depth trick
(https://github.com/astral-sh/ty/issues/1433,
https://github.com/astral-sh/ty/issues/1415), which means we reach a
fixed point much sooner.

## Ecosystem analysis

The changes look good overall.
You may notice changes in the converged values ​​for recursive types,
this is because the way recursive types are normalized has been changed.
Previously, types containing `Divergent` types were normalized by
replacing them with the `Divergent` type itself, but in this PR, types
with a nesting level of 2 or more that contain `Divergent` types are
normalized by replacing them with a type with a nesting level of 1. This
means that information about the non-divergent parts of recursive types
is no longer lost.

```python
# previous
tuple[tuple[Divergent, int], int] => Divergent
# now
tuple[tuple[Divergent, int], int] => tuple[Divergent, int]
```

The false positive error introduced in this PR occurs in class
definitions with self-referential base classes, such as the one below.

```python
from typing_extensions import Generic, TypeVar

T = TypeVar("T")
U = TypeVar("U")

class Base2(Generic[T, U]): ...

# TODO: no error
# error: [unsupported-base] "Unsupported class base with type `<class 'Base2[Sub2, U@Sub2]'> | <class 'Base2[Sub2[Unknown], U@Sub2]'>`"
class Sub2(Base2["Sub2", U]): ...
```

This is due to the lack of support for unions of MROs, or because cyclic
legacy generic types are not inferred as generic types early in the
query cycle.

## Test Plan

All samples listed in astral-sh/ty#256 are tested and passed without any
panic!

## Acknowledgments

Thanks to @MichaReiser for working on bug fixes and improvements to
salsa for this PR. @carljm also contributed early on to the discussion
of the query convergence mechanism proposed in this PR.

---------

Co-authored-by: Carl Meyer <carl@astral.sh>

.github/workflows/ci.yaml

@@ -284,6 +284,10 @@ jobs:
         run: cargo insta test --all-features --unreferenced reject --test-runner nextest
       - name: Dogfood ty on py-fuzzer
         run: uv run --project=./python/py-fuzzer cargo run -p ty check --project=./python/py-fuzzer
+      - name: Dogfood ty on the scripts directory
+        run: uv run --project=./scripts cargo run -p ty check --project=./scripts
+      - name: Dogfood ty on ty_benchmark
+        run: uv run --project=./scripts/ty_benchmark cargo run -p ty check --project=./scripts/ty_benchmark
       # Check for broken links in the documentation.
       - run: cargo doc --all --no-deps
         env:

.vscode/settings.json

@@ -5,5 +5,6 @@
     "rust-analyzer.check.command": "clippy",
     "search.exclude": {
         "**/*.snap": true
-    }
+    },
+    "ty.diagnosticMode": "openFilesOnly"
 }

Cargo.lock

@@ -4474,6 +4474,7 @@ dependencies = [
  "quickcheck_macros",
  "ruff_annotate_snippets",
  "ruff_db",
+ "ruff_diagnostics",
  "ruff_index",
  "ruff_macros",
  "ruff_memory_usage",
@@ -4519,6 +4520,7 @@ dependencies = [
  "lsp-types",
  "regex",
  "ruff_db",
+ "ruff_diagnostics",
  "ruff_macros",
  "ruff_notebook",
  "ruff_python_ast",

crates/ruff_linter/resources/test/fixtures/flake8_bandit/S310.py

@@ -45,3 +45,22 @@ urllib.request.urlopen(urllib.request.Request(url))
 # https://github.com/astral-sh/ruff/issues/15522
 map(urllib.request.urlopen, [])
 foo = urllib.request.urlopen
+
+# https://github.com/astral-sh/ruff/issues/21462
+path = "https://example.com/data.csv"
+urllib.request.urlretrieve(path, "data.csv")
+url = "https://example.com/api"
+urllib.request.Request(url)
+
+# Test resolved f-strings and concatenated string literals
+fstring_url = f"https://example.com/data.csv"
+urllib.request.urlopen(fstring_url)
+urllib.request.Request(fstring_url)
+
+concatenated_url = "https://" + "example.com/data.csv"
+urllib.request.urlopen(concatenated_url)
+urllib.request.Request(concatenated_url)
+
+nested_concatenated = "http://" + "example.com" + "/data.csv"
+urllib.request.urlopen(nested_concatenated)
+urllib.request.Request(nested_concatenated)

crates/ruff_linter/resources/test/fixtures/ruff/RUF066.py

@@ -0,0 +1,70 @@
+import abc
+import typing
+
+
+class User:  # Test normal class properties
+    @property
+    def name(self):  # ERROR: No return
+        f"{self.first_name} {self.last_name}"
+
+    @property
+    def age(self):  # OK: Returning something
+        return 100
+
+    def method(self):  # OK: Not a property
+        x = 1
+
+    @property
+    def nested(self):  # ERROR: Property itself doesn't return
+        def inner():
+            return 0
+
+    @property
+    def stub(self): ...  # OK: A stub; doesn't return anything
+
+
+class UserMeta(metaclass=abc.ABCMeta):  # Test properies inside of an ABC class
+    @property
+    @abc.abstractmethod
+    def abstr_prop1(self): ...  # OK: Abstract methods doesn't need to return anything
+
+    @property
+    @abc.abstractmethod
+    def abstr_prop2(self):  # OK: Abstract methods doesn't need to return anything
+        """
+        A cool docstring
+        """
+
+    @property
+    def prop1(self):  # OK: Returning a value
+        return 1
+
+    @property
+    def prop2(self):  # ERROR: Not returning something (even when we are inside an ABC)
+        50
+
+    def method(self):  # OK: Not a property
+        x = 1
+
+
+def func():  # OK: Not a property
+    x = 1
+
+
+class Proto(typing.Protocol):  # Tests for a Protocol class
+    @property
+    def prop1(self) -> int: ...  # OK: A stub property
+
+
+class File:  # Extra tests for things like yield/yield from/raise
+    @property
+    def stream1(self):  # OK: Yields something
+        yield
+
+    @property
+    def stream2(self):  # OK: Yields from something
+        yield from self.stream1
+
+    @property
+    def children(self):  # OK: Raises
+        raise ValueError("File does not have children")

crates/ruff_linter/src/checkers/ast/analyze/statement.rs

@@ -347,6 +347,9 @@ pub(crate) fn statement(stmt: &Stmt, checker: &mut Checker) {
             if checker.is_rule_enabled(Rule::InvalidArgumentName) {
                 pep8_naming::rules::invalid_argument_name_function(checker, function_def);
             }
+            if checker.is_rule_enabled(Rule::PropertyWithoutReturn) {
+                ruff::rules::property_without_return(checker, function_def);
+            }
         }
         Stmt::Return(_) => {
             if checker.is_rule_enabled(Rule::ReturnInInit) {

crates/ruff_linter/src/codes.rs

@@ -1058,6 +1058,7 @@ pub fn code_to_rule(linter: Linter, code: &str) -> Option<(RuleGroup, Rule)> {
         (Ruff, "063") => rules::ruff::rules::AccessAnnotationsFromClassDict,
         (Ruff, "064") => rules::ruff::rules::NonOctalPermissions,
         (Ruff, "065") => rules::ruff::rules::LoggingEagerConversion,
+        (Ruff, "066") => rules::ruff::rules::PropertyWithoutReturn,
 
         (Ruff, "100") => rules::ruff::rules::UnusedNOQA,
         (Ruff, "101") => rules::ruff::rules::RedirectedNOQA,

crates/ruff_linter/src/preview.rs

@@ -279,3 +279,10 @@ pub(crate) const fn is_extended_snmp_api_path_detection_enabled(settings: &Linte
 pub(crate) const fn is_enumerate_for_loop_int_index_enabled(settings: &LinterSettings) -> bool {
     settings.preview.is_enabled()
 }
+
+// https://github.com/astral-sh/ruff/pull/21469
+pub(crate) const fn is_s310_resolve_string_literal_bindings_enabled(
+    settings: &LinterSettings,
+) -> bool {
+    settings.preview.is_enabled()
+}

crates/ruff_linter/src/rules/flake8_bandit/mod.rs

@@ -10,11 +10,11 @@ mod tests {
     use anyhow::Result;
     use test_case::test_case;
 
-    use crate::assert_diagnostics;
     use crate::registry::Rule;
     use crate::settings::LinterSettings;
     use crate::settings::types::PreviewMode;
     use crate::test::test_path;
+    use crate::{assert_diagnostics, assert_diagnostics_diff};
 
     #[test_case(Rule::Assert, Path::new("S101.py"))]
     #[test_case(Rule::BadFilePermissions, Path::new("S103.py"))]
@@ -112,14 +112,19 @@ mod tests {
             rule_code.noqa_code(),
             path.to_string_lossy()
         );
-        let diagnostics = test_path(
+
+        assert_diagnostics_diff!(
+            snapshot,
             Path::new("flake8_bandit").join(path).as_path(),
+            &LinterSettings {
+                preview: PreviewMode::Disabled,
+                ..LinterSettings::for_rule(rule_code)
+            },
             &LinterSettings {
                 preview: PreviewMode::Enabled,
                 ..LinterSettings::for_rule(rule_code)
-            },
-        )?;
-        assert_diagnostics!(snapshot, diagnostics);
+            }
+        );
         Ok(())
     }
 

crates/ruff_linter/src/rules/flake8_bandit/rules/suspicious_function_call.rs

@@ -4,11 +4,16 @@
 use itertools::Either;
 use ruff_macros::{ViolationMetadata, derive_message_formats};
 use ruff_python_ast::{self as ast, Arguments, Decorator, Expr, ExprCall, Operator};
+use ruff_python_semantic::SemanticModel;
+use ruff_python_semantic::analyze::typing::find_binding_value;
 use ruff_text_size::{Ranged, TextRange};
 
 use crate::Violation;
 use crate::checkers::ast::Checker;
-use crate::preview::is_suspicious_function_reference_enabled;
+use crate::preview::{
+    is_s310_resolve_string_literal_bindings_enabled, is_suspicious_function_reference_enabled,
+};
+use crate::settings::LinterSettings;
 
 /// ## What it does
 /// Checks for calls to `pickle` functions or modules that wrap them.
@@ -1016,6 +1021,25 @@ fn suspicious_function(
             || has_prefix(chars.skip_while(|c| c.is_whitespace()), "https://")
     }
 
+    /// Resolves `expr` to its binding and checks if the resolved expression starts with an HTTP or HTTPS prefix.
+    fn expression_starts_with_http_prefix(
+        expr: &Expr,
+        semantic: &SemanticModel,
+        settings: &LinterSettings,
+    ) -> bool {
+        let resolved_expression = if is_s310_resolve_string_literal_bindings_enabled(settings)
+            && let Some(name_expr) = expr.as_name_expr()
+            && let Some(binding_id) = semantic.only_binding(name_expr)
+            && let Some(value) = find_binding_value(semantic.binding(binding_id), semantic)
+        {
+            value
+        } else {
+            expr
+        };
+
+        leading_chars(resolved_expression).is_some_and(has_http_prefix)
+    }
+
     /// Return the leading characters for an expression, if it's a string literal, f-string, or
     /// string concatenation.
     fn leading_chars(expr: &Expr) -> Option<impl Iterator<Item = char> + Clone + '_> {
@@ -1139,17 +1163,19 @@ fn suspicious_function(
         // URLOpen (`Request`)
         ["urllib", "request", "Request"] | ["six", "moves", "urllib", "request", "Request"] => {
             if let Some(arguments) = arguments {
-                // If the `url` argument is a string literal or an f-string, allow `http` and `https` schemes.
+                // If the `url` argument is a string literal (including resolved bindings), allow `http` and `https` schemes.
                 if arguments.args.iter().all(|arg| !arg.is_starred_expr())
                     && arguments
                         .keywords
                         .iter()
                         .all(|keyword| keyword.arg.is_some())
                 {
-                    if arguments
-                        .find_argument_value("url", 0)
-                        .and_then(leading_chars)
-                        .is_some_and(has_http_prefix)
+                    if let Some(url_expr) = arguments.find_argument_value("url", 0)
+                        && expression_starts_with_http_prefix(
+                            url_expr,
+                            checker.semantic(),
+                            checker.settings(),
+                        )
                     {
                         return;
                     }
@@ -1186,19 +1212,25 @@ fn suspicious_function(
                                     name.segments() == ["urllib", "request", "Request"]
                                 })
                             {
-                                if arguments
-                                    .find_argument_value("url", 0)
-                                    .and_then(leading_chars)
-                                    .is_some_and(has_http_prefix)
+                                if let Some(url_expr) = arguments.find_argument_value("url", 0)
+                                    && expression_starts_with_http_prefix(
+                                        url_expr,
+                                        checker.semantic(),
+                                        checker.settings(),
+                                    )
                                 {
                                     return;
                                 }
                             }
                         }
 
-                        // If the `url` argument is a string literal, allow `http` and `https` schemes.
+                        // If the `url` argument is a string literal (including resolved bindings), allow `http` and `https` schemes.
                         Some(expr) => {
-                            if leading_chars(expr).is_some_and(has_http_prefix) {
+                            if expression_starts_with_http_prefix(
+                                expr,
+                                checker.semantic(),
+                                checker.settings(),
+                            ) {
                                 return;
                             }
                         }

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__S310_S310.py.snap

@@ -254,3 +254,84 @@ S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom sch
 42 | urllib.request.urlopen(urllib.request.Request(url))
    |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:51:1
+   |
+49 | # https://github.com/astral-sh/ruff/issues/21462
+50 | path = "https://example.com/data.csv"
+51 | urllib.request.urlretrieve(path, "data.csv")
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+52 | url = "https://example.com/api"
+53 | urllib.request.Request(url)
+   |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:53:1
+   |
+51 | urllib.request.urlretrieve(path, "data.csv")
+52 | url = "https://example.com/api"
+53 | urllib.request.Request(url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+54 |
+55 | # Test resolved f-strings and concatenated string literals
+   |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:57:1
+   |
+55 | # Test resolved f-strings and concatenated string literals
+56 | fstring_url = f"https://example.com/data.csv"
+57 | urllib.request.urlopen(fstring_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+58 | urllib.request.Request(fstring_url)
+   |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:58:1
+   |
+56 | fstring_url = f"https://example.com/data.csv"
+57 | urllib.request.urlopen(fstring_url)
+58 | urllib.request.Request(fstring_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+59 |
+60 | concatenated_url = "https://" + "example.com/data.csv"
+   |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:61:1
+   |
+60 | concatenated_url = "https://" + "example.com/data.csv"
+61 | urllib.request.urlopen(concatenated_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+62 | urllib.request.Request(concatenated_url)
+   |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:62:1
+   |
+60 | concatenated_url = "https://" + "example.com/data.csv"
+61 | urllib.request.urlopen(concatenated_url)
+62 | urllib.request.Request(concatenated_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+63 |
+64 | nested_concatenated = "http://" + "example.com" + "/data.csv"
+   |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:65:1
+   |
+64 | nested_concatenated = "http://" + "example.com" + "/data.csv"
+65 | urllib.request.urlopen(nested_concatenated)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+66 | urllib.request.Request(nested_concatenated)
+   |
+
+S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
+  --> S310.py:66:1
+   |
+64 | nested_concatenated = "http://" + "example.com" + "/data.csv"
+65 | urllib.request.urlopen(nested_concatenated)
+66 | urllib.request.Request(nested_concatenated)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S301_S301.py.snap

@@ -1,15 +1,15 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S301 `pickle` and modules that wrap it can be unsafe when used to deserialize untrusted data, possible security issue
- --> S301.py:3:1
-  |
-1 | import pickle
-2 |
-3 | pickle.loads()
-  | ^^^^^^^^^^^^^^
-  |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
+--- Summary ---
+Removed: 0
+Added: 2
+
+--- Added ---
 S301 `pickle` and modules that wrap it can be unsafe when used to deserialize untrusted data, possible security issue
  --> S301.py:7:5
   |
@@ -19,6 +19,7 @@ S301 `pickle` and modules that wrap it can be unsafe when used to deserialize un
 8 | foo = pickle.load
   |
 
+
 S301 `pickle` and modules that wrap it can be unsafe when used to deserialize untrusted data, possible security issue
  --> S301.py:8:7
   |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S307_S307.py.snap

@@ -1,24 +1,15 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S307 Use of possibly insecure function; consider using `ast.literal_eval`
- --> S307.py:3:7
-  |
-1 | import os
-2 |
-3 | print(eval("1+1"))  # S307
-  |       ^^^^^^^^^^^
-4 | print(eval("os.getcwd()"))  # S307
-  |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
-S307 Use of possibly insecure function; consider using `ast.literal_eval`
- --> S307.py:4:7
-  |
-3 | print(eval("1+1"))  # S307
-4 | print(eval("os.getcwd()"))  # S307
-  |       ^^^^^^^^^^^^^^^^^^^
-  |
+--- Summary ---
+Removed: 0
+Added: 2
 
+--- Added ---
 S307 Use of possibly insecure function; consider using `ast.literal_eval`
   --> S307.py:16:5
    |
@@ -28,6 +19,7 @@ S307 Use of possibly insecure function; consider using `ast.literal_eval`
 17 | foo = eval
    |
 
+
 S307 Use of possibly insecure function; consider using `ast.literal_eval`
   --> S307.py:17:7
    |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S308_S308.py.snap

@@ -1,60 +1,37 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
- --> S308.py:6:5
-  |
-4 | def bad_func():
-5 |     inject = "harmful_input"
-6 |     mark_safe(inject)
-  |     ^^^^^^^^^^^^^^^^^
-7 |     mark_safe("I will add" + inject + "to my string")
-8 |     mark_safe("I will add %s to my string" % inject)
-  |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
- --> S308.py:7:5
-  |
-5 |     inject = "harmful_input"
-6 |     mark_safe(inject)
-7 |     mark_safe("I will add" + inject + "to my string")
-  |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-8 |     mark_safe("I will add %s to my string" % inject)
-9 |     mark_safe("I will add {} to my string".format(inject))
-  |
+--- Summary ---
+Removed: 2
+Added: 4
 
+--- Removed ---
 S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:8:5
+  --> S308.py:16:1
    |
- 6 |     mark_safe(inject)
- 7 |     mark_safe("I will add" + inject + "to my string")
- 8 |     mark_safe("I will add %s to my string" % inject)
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
- 9 |     mark_safe("I will add {} to my string".format(inject))
-10 |     mark_safe(f"I will add {inject} to my string")
+16 | @mark_safe
+   | ^^^^^^^^^^
+17 | def some_func():
+18 |     return '<script>alert("evil!")</script>'
    |
 
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:9:5
-   |
- 7 |     mark_safe("I will add" + inject + "to my string")
- 8 |     mark_safe("I will add %s to my string" % inject)
- 9 |     mark_safe("I will add {} to my string".format(inject))
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-10 |     mark_safe(f"I will add {inject} to my string")
-   |
 
 S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:10:5
+  --> S308.py:36:1
    |
- 8 |     mark_safe("I will add %s to my string" % inject)
- 9 |     mark_safe("I will add {} to my string".format(inject))
-10 |     mark_safe(f"I will add {inject} to my string")
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-11 |
-12 | def good_func():
+36 | @mark_safe
+   | ^^^^^^^^^^
+37 | def some_func():
+38 |     return '<script>alert("evil!")</script>'
    |
 
+
+
+--- Added ---
 S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
   --> S308.py:16:2
    |
@@ -64,59 +41,6 @@ S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
 18 |     return '<script>alert("evil!")</script>'
    |
 
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:26:5
-   |
-24 | def bad_func():
-25 |     inject = "harmful_input"
-26 |     mark_safe(inject)
-   |     ^^^^^^^^^^^^^^^^^
-27 |     mark_safe("I will add" + inject + "to my string")
-28 |     mark_safe("I will add %s to my string" % inject)
-   |
-
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:27:5
-   |
-25 |     inject = "harmful_input"
-26 |     mark_safe(inject)
-27 |     mark_safe("I will add" + inject + "to my string")
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-28 |     mark_safe("I will add %s to my string" % inject)
-29 |     mark_safe("I will add {} to my string".format(inject))
-   |
-
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:28:5
-   |
-26 |     mark_safe(inject)
-27 |     mark_safe("I will add" + inject + "to my string")
-28 |     mark_safe("I will add %s to my string" % inject)
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-29 |     mark_safe("I will add {} to my string".format(inject))
-30 |     mark_safe(f"I will add {inject} to my string")
-   |
-
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:29:5
-   |
-27 |     mark_safe("I will add" + inject + "to my string")
-28 |     mark_safe("I will add %s to my string" % inject)
-29 |     mark_safe("I will add {} to my string".format(inject))
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-30 |     mark_safe(f"I will add {inject} to my string")
-   |
-
-S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
-  --> S308.py:30:5
-   |
-28 |     mark_safe("I will add %s to my string" % inject)
-29 |     mark_safe("I will add {} to my string".format(inject))
-30 |     mark_safe(f"I will add {inject} to my string")
-   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-31 |
-32 | def good_func():
-   |
 
 S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
   --> S308.py:36:2
@@ -127,6 +51,7 @@ S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
 38 |     return '<script>alert("evil!")</script>'
    |
 
+
 S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
   --> S308.py:42:5
    |
@@ -136,6 +61,7 @@ S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
 43 | foo = mark_safe
    |
 
+
 S308 Use of `mark_safe` may expose cross-site scripting vulnerabilities
   --> S308.py:43:7
    |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S310_S310.py.snap

@@ -1,260 +1,106 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
- --> S310.py:6:1
-  |
-4 | urllib.request.urlopen(url=f'http://www.google.com')
-5 | urllib.request.urlopen(url='http://' + 'www' + '.google.com')
-6 | urllib.request.urlopen(url='http://www.google.com', **kwargs)
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-7 | urllib.request.urlopen(url=f'http://www.google.com', **kwargs)
-8 | urllib.request.urlopen('http://www.google.com')
-  |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
- --> S310.py:7:1
-  |
-5 | urllib.request.urlopen(url='http://' + 'www' + '.google.com')
-6 | urllib.request.urlopen(url='http://www.google.com', **kwargs)
-7 | urllib.request.urlopen(url=f'http://www.google.com', **kwargs)
-  | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-8 | urllib.request.urlopen('http://www.google.com')
-9 | urllib.request.urlopen(f'http://www.google.com')
-  |
+--- Summary ---
+Removed: 8
+Added: 2
 
+--- Removed ---
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:10:1
+  --> S310.py:51:1
    |
- 8 | urllib.request.urlopen('http://www.google.com')
- 9 | urllib.request.urlopen(f'http://www.google.com')
-10 | urllib.request.urlopen('file:///foo/bar/baz')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-11 | urllib.request.urlopen(url)
+49 | # https://github.com/astral-sh/ruff/issues/21462
+50 | path = "https://example.com/data.csv"
+51 | urllib.request.urlretrieve(path, "data.csv")
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+52 | url = "https://example.com/api"
+53 | urllib.request.Request(url)
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:11:1
+  --> S310.py:53:1
    |
- 9 | urllib.request.urlopen(f'http://www.google.com')
-10 | urllib.request.urlopen('file:///foo/bar/baz')
-11 | urllib.request.urlopen(url)
+51 | urllib.request.urlretrieve(path, "data.csv")
+52 | url = "https://example.com/api"
+53 | urllib.request.Request(url)
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-12 |
-13 | urllib.request.Request(url='http://www.google.com')
+54 |
+55 | # Test resolved f-strings and concatenated string literals
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:16:1
+  --> S310.py:57:1
    |
-14 | urllib.request.Request(url=f'http://www.google.com')
-15 | urllib.request.Request(url='http://' + 'www' + '.google.com')
-16 | urllib.request.Request(url='http://www.google.com', **kwargs)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-17 | urllib.request.Request(url=f'http://www.google.com', **kwargs)
-18 | urllib.request.Request('http://www.google.com')
+55 | # Test resolved f-strings and concatenated string literals
+56 | fstring_url = f"https://example.com/data.csv"
+57 | urllib.request.urlopen(fstring_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+58 | urllib.request.Request(fstring_url)
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:17:1
+  --> S310.py:58:1
    |
-15 | urllib.request.Request(url='http://' + 'www' + '.google.com')
-16 | urllib.request.Request(url='http://www.google.com', **kwargs)
-17 | urllib.request.Request(url=f'http://www.google.com', **kwargs)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-18 | urllib.request.Request('http://www.google.com')
-19 | urllib.request.Request(f'http://www.google.com')
+56 | fstring_url = f"https://example.com/data.csv"
+57 | urllib.request.urlopen(fstring_url)
+58 | urllib.request.Request(fstring_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+59 |
+60 | concatenated_url = "https://" + "example.com/data.csv"
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:20:1
+  --> S310.py:61:1
    |
-18 | urllib.request.Request('http://www.google.com')
-19 | urllib.request.Request(f'http://www.google.com')
-20 | urllib.request.Request('file:///foo/bar/baz')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-21 | urllib.request.Request(url)
+60 | concatenated_url = "https://" + "example.com/data.csv"
+61 | urllib.request.urlopen(concatenated_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+62 | urllib.request.Request(concatenated_url)
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:21:1
+  --> S310.py:62:1
    |
-19 | urllib.request.Request(f'http://www.google.com')
-20 | urllib.request.Request('file:///foo/bar/baz')
-21 | urllib.request.Request(url)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-22 |
-23 | urllib.request.URLopener().open(fullurl='http://www.google.com')
+60 | concatenated_url = "https://" + "example.com/data.csv"
+61 | urllib.request.urlopen(concatenated_url)
+62 | urllib.request.Request(concatenated_url)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+63 |
+64 | nested_concatenated = "http://" + "example.com" + "/data.csv"
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:23:1
+  --> S310.py:65:1
    |
-21 | urllib.request.Request(url)
-22 |
-23 | urllib.request.URLopener().open(fullurl='http://www.google.com')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-24 | urllib.request.URLopener().open(fullurl=f'http://www.google.com')
-25 | urllib.request.URLopener().open(fullurl='http://' + 'www' + '.google.com')
+64 | nested_concatenated = "http://" + "example.com" + "/data.csv"
+65 | urllib.request.urlopen(nested_concatenated)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+66 | urllib.request.Request(nested_concatenated)
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:24:1
+  --> S310.py:66:1
    |
-23 | urllib.request.URLopener().open(fullurl='http://www.google.com')
-24 | urllib.request.URLopener().open(fullurl=f'http://www.google.com')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-25 | urllib.request.URLopener().open(fullurl='http://' + 'www' + '.google.com')
-26 | urllib.request.URLopener().open(fullurl='http://www.google.com', **kwargs)
+64 | nested_concatenated = "http://" + "example.com" + "/data.csv"
+65 | urllib.request.urlopen(nested_concatenated)
+66 | urllib.request.Request(nested_concatenated)
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
 
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:25:1
-   |
-23 | urllib.request.URLopener().open(fullurl='http://www.google.com')
-24 | urllib.request.URLopener().open(fullurl=f'http://www.google.com')
-25 | urllib.request.URLopener().open(fullurl='http://' + 'www' + '.google.com')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-26 | urllib.request.URLopener().open(fullurl='http://www.google.com', **kwargs)
-27 | urllib.request.URLopener().open(fullurl=f'http://www.google.com', **kwargs)
-   |
 
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:26:1
-   |
-24 | urllib.request.URLopener().open(fullurl=f'http://www.google.com')
-25 | urllib.request.URLopener().open(fullurl='http://' + 'www' + '.google.com')
-26 | urllib.request.URLopener().open(fullurl='http://www.google.com', **kwargs)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-27 | urllib.request.URLopener().open(fullurl=f'http://www.google.com', **kwargs)
-28 | urllib.request.URLopener().open('http://www.google.com')
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:27:1
-   |
-25 | urllib.request.URLopener().open(fullurl='http://' + 'www' + '.google.com')
-26 | urllib.request.URLopener().open(fullurl='http://www.google.com', **kwargs)
-27 | urllib.request.URLopener().open(fullurl=f'http://www.google.com', **kwargs)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-28 | urllib.request.URLopener().open('http://www.google.com')
-29 | urllib.request.URLopener().open(f'http://www.google.com')
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:28:1
-   |
-26 | urllib.request.URLopener().open(fullurl='http://www.google.com', **kwargs)
-27 | urllib.request.URLopener().open(fullurl=f'http://www.google.com', **kwargs)
-28 | urllib.request.URLopener().open('http://www.google.com')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-29 | urllib.request.URLopener().open(f'http://www.google.com')
-30 | urllib.request.URLopener().open('http://' + 'www' + '.google.com')
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:29:1
-   |
-27 | urllib.request.URLopener().open(fullurl=f'http://www.google.com', **kwargs)
-28 | urllib.request.URLopener().open('http://www.google.com')
-29 | urllib.request.URLopener().open(f'http://www.google.com')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-30 | urllib.request.URLopener().open('http://' + 'www' + '.google.com')
-31 | urllib.request.URLopener().open('file:///foo/bar/baz')
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:30:1
-   |
-28 | urllib.request.URLopener().open('http://www.google.com')
-29 | urllib.request.URLopener().open(f'http://www.google.com')
-30 | urllib.request.URLopener().open('http://' + 'www' + '.google.com')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-31 | urllib.request.URLopener().open('file:///foo/bar/baz')
-32 | urllib.request.URLopener().open(url)
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:31:1
-   |
-29 | urllib.request.URLopener().open(f'http://www.google.com')
-30 | urllib.request.URLopener().open('http://' + 'www' + '.google.com')
-31 | urllib.request.URLopener().open('file:///foo/bar/baz')
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-32 | urllib.request.URLopener().open(url)
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:32:1
-   |
-30 | urllib.request.URLopener().open('http://' + 'www' + '.google.com')
-31 | urllib.request.URLopener().open('file:///foo/bar/baz')
-32 | urllib.request.URLopener().open(url)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^
-33 |
-34 | urllib.request.urlopen(url=urllib.request.Request('http://www.google.com'))
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:37:1
-   |
-35 | urllib.request.urlopen(url=urllib.request.Request(f'http://www.google.com'))
-36 | urllib.request.urlopen(url=urllib.request.Request('http://' + 'www' + '.google.com'))
-37 | urllib.request.urlopen(url=urllib.request.Request('http://www.google.com'), **kwargs)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-38 | urllib.request.urlopen(url=urllib.request.Request(f'http://www.google.com'), **kwargs)
-39 | urllib.request.urlopen(urllib.request.Request('http://www.google.com'))
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:38:1
-   |
-36 | urllib.request.urlopen(url=urllib.request.Request('http://' + 'www' + '.google.com'))
-37 | urllib.request.urlopen(url=urllib.request.Request('http://www.google.com'), **kwargs)
-38 | urllib.request.urlopen(url=urllib.request.Request(f'http://www.google.com'), **kwargs)
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-39 | urllib.request.urlopen(urllib.request.Request('http://www.google.com'))
-40 | urllib.request.urlopen(urllib.request.Request(f'http://www.google.com'))
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:41:1
-   |
-39 | urllib.request.urlopen(urllib.request.Request('http://www.google.com'))
-40 | urllib.request.urlopen(urllib.request.Request(f'http://www.google.com'))
-41 | urllib.request.urlopen(urllib.request.Request('file:///foo/bar/baz'))
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-42 | urllib.request.urlopen(urllib.request.Request(url))
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:41:24
-   |
-39 | urllib.request.urlopen(urllib.request.Request('http://www.google.com'))
-40 | urllib.request.urlopen(urllib.request.Request(f'http://www.google.com'))
-41 | urllib.request.urlopen(urllib.request.Request('file:///foo/bar/baz'))
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-42 | urllib.request.urlopen(urllib.request.Request(url))
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:42:1
-   |
-40 | urllib.request.urlopen(urllib.request.Request(f'http://www.google.com'))
-41 | urllib.request.urlopen(urllib.request.Request('file:///foo/bar/baz'))
-42 | urllib.request.urlopen(urllib.request.Request(url))
-   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-
-S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
-  --> S310.py:42:24
-   |
-40 | urllib.request.urlopen(urllib.request.Request(f'http://www.google.com'))
-41 | urllib.request.urlopen(urllib.request.Request('file:///foo/bar/baz'))
-42 | urllib.request.urlopen(urllib.request.Request(url))
-   |                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
 
+--- Added ---
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
   --> S310.py:46:5
    |
@@ -264,6 +110,7 @@ S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom sch
 47 | foo = urllib.request.urlopen
    |
 
+
 S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom schemes is often unexpected.
   --> S310.py:47:7
    |
@@ -271,4 +118,6 @@ S310 Audit URL open for permitted schemes. Allowing use of `file:` or custom sch
 46 | map(urllib.request.urlopen, [])
 47 | foo = urllib.request.urlopen
    |       ^^^^^^^^^^^^^^^^^^^^^^
+48 |
+49 | # https://github.com/astral-sh/ruff/issues/21462
    |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S311_S311.py.snap

@@ -1,103 +1,15 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:10:1
-   |
- 9 | # Errors
-10 | random.Random()
-   | ^^^^^^^^^^^^^^^
-11 | random.random()
-12 | random.randrange()
-   |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:11:1
-   |
- 9 | # Errors
-10 | random.Random()
-11 | random.random()
-   | ^^^^^^^^^^^^^^^
-12 | random.randrange()
-13 | random.randint()
-   |
-
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:12:1
-   |
-10 | random.Random()
-11 | random.random()
-12 | random.randrange()
-   | ^^^^^^^^^^^^^^^^^^
-13 | random.randint()
-14 | random.choice()
-   |
-
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:13:1
-   |
-11 | random.random()
-12 | random.randrange()
-13 | random.randint()
-   | ^^^^^^^^^^^^^^^^
-14 | random.choice()
-15 | random.choices()
-   |
-
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:14:1
-   |
-12 | random.randrange()
-13 | random.randint()
-14 | random.choice()
-   | ^^^^^^^^^^^^^^^
-15 | random.choices()
-16 | random.uniform()
-   |
-
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:15:1
-   |
-13 | random.randint()
-14 | random.choice()
-15 | random.choices()
-   | ^^^^^^^^^^^^^^^^
-16 | random.uniform()
-17 | random.triangular()
-   |
-
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:16:1
-   |
-14 | random.choice()
-15 | random.choices()
-16 | random.uniform()
-   | ^^^^^^^^^^^^^^^^
-17 | random.triangular()
-18 | random.randbytes()
-   |
-
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:17:1
-   |
-15 | random.choices()
-16 | random.uniform()
-17 | random.triangular()
-   | ^^^^^^^^^^^^^^^^^^^
-18 | random.randbytes()
-   |
-
-S311 Standard pseudo-random generators are not suitable for cryptographic purposes
-  --> S311.py:18:1
-   |
-16 | random.uniform()
-17 | random.triangular()
-18 | random.randbytes()
-   | ^^^^^^^^^^^^^^^^^^
-19 |
-20 | # Unrelated
-   |
+--- Summary ---
+Removed: 0
+Added: 2
 
+--- Added ---
 S311 Standard pseudo-random generators are not suitable for cryptographic purposes
   --> S311.py:26:5
    |
@@ -107,6 +19,7 @@ S311 Standard pseudo-random generators are not suitable for cryptographic purpos
 27 | foo = random.randrange
    |
 
+
 S311 Standard pseudo-random generators are not suitable for cryptographic purposes
   --> S311.py:27:7
    |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S312_S312.py.snap

@@ -1,15 +1,15 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
- --> S312.py:3:1
-  |
-1 | from telnetlib import Telnet
-2 |
-3 | Telnet("localhost", 23)
-  | ^^^^^^^^^^^^^^^^^^^^^^^
-  |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
+--- Summary ---
+Removed: 0
+Added: 3
+
+--- Added ---
 S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
  --> S312.py:7:5
   |
@@ -19,6 +19,7 @@ S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
 8 | foo = Telnet
   |
 
+
 S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
   --> S312.py:8:7
    |
@@ -30,6 +31,7 @@ S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
 10 | import telnetlib
    |
 
+
 S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
   --> S312.py:11:5
    |
@@ -39,13 +41,3 @@ S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
 12 |
 13 | from typing import Annotated
    |
-
-S312 Telnet is considered insecure. Use SSH or some other encrypted protocol.
-  --> S312.py:14:24
-   |
-13 | from typing import Annotated
-14 | foo: Annotated[Telnet, telnetlib.Telnet()]
-   |                        ^^^^^^^^^^^^^^^^^^
-15 |
-16 | def _() -> Telnet: ...
-   |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S508_S508.py.snap

@@ -1,26 +1,15 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
- --> S508.py:3:25
-  |
-1 | from pysnmp.hlapi import CommunityData
-2 |
-3 | CommunityData("public", mpModel=0)  # S508
-  |                         ^^^^^^^^^
-4 | CommunityData("public", mpModel=1)  # S508
-  |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
-S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
- --> S508.py:4:25
-  |
-3 | CommunityData("public", mpModel=0)  # S508
-4 | CommunityData("public", mpModel=1)  # S508
-  |                         ^^^^^^^^^
-5 |
-6 | CommunityData("public", mpModel=2)  # OK
-  |
+--- Summary ---
+Removed: 0
+Added: 8
 
+--- Added ---
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:18:46
    |
@@ -32,6 +21,7 @@ S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
 20 | pysnmp.hlapi.v1arch.asyncio.CommunityData("public", mpModel=0)  # S508
    |
 
+
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:19:58
    |
@@ -42,6 +32,7 @@ S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
 21 | pysnmp.hlapi.v1arch.CommunityData("public", mpModel=0)  # S508
    |
 
+
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:20:53
    |
@@ -53,6 +44,7 @@ S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
 22 | pysnmp.hlapi.v3arch.asyncio.auth.CommunityData("public", mpModel=0)  # S508
    |
 
+
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:21:45
    |
@@ -64,6 +56,7 @@ S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
 23 | pysnmp.hlapi.v3arch.asyncio.CommunityData("public", mpModel=0)  # S508
    |
 
+
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:22:58
    |
@@ -75,6 +68,7 @@ S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
 24 | pysnmp.hlapi.v3arch.CommunityData("public", mpModel=0)  # S508
    |
 
+
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:23:53
    |
@@ -86,6 +80,7 @@ S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
 25 | pysnmp.hlapi.auth.CommunityData("public", mpModel=0)  # S508
    |
 
+
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:24:45
    |
@@ -96,6 +91,7 @@ S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
 25 | pysnmp.hlapi.auth.CommunityData("public", mpModel=0)  # S508
    |
 
+
 S508 The use of SNMPv1 and SNMPv2 is insecure. Use SNMPv3 if able.
   --> S508.py:25:43
    |

crates/ruff_linter/src/rules/flake8_bandit/snapshots/ruff_linter__rules__flake8_bandit__tests__preview__S509_S509.py.snap

@@ -1,24 +1,15 @@
 ---
 source: crates/ruff_linter/src/rules/flake8_bandit/mod.rs
 ---
-S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure.
- --> S509.py:4:12
-  |
-4 | insecure = UsmUserData("securityName")  # S509
-  |            ^^^^^^^^^^^
-5 | auth_no_priv = UsmUserData("securityName", "authName")  # S509
-  |
+--- Linter settings ---
+-linter.preview = disabled
++linter.preview = enabled
 
-S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure.
- --> S509.py:5:16
-  |
-4 | insecure = UsmUserData("securityName")  # S509
-5 | auth_no_priv = UsmUserData("securityName", "authName")  # S509
-  |                ^^^^^^^^^^^
-6 |
-7 | less_insecure = UsmUserData("securityName", "authName", "privName")  # OK
-  |
+--- Summary ---
+Removed: 0
+Added: 4
 
+--- Added ---
 S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure.
   --> S509.py:15:1
    |
@@ -30,6 +21,7 @@ S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv`
 17 | pysnmp.hlapi.v3arch.asyncio.auth.UsmUserData("user")  # S509
    |
 
+
 S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure.
   --> S509.py:16:1
    |
@@ -40,6 +32,7 @@ S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv`
 18 | pysnmp.hlapi.auth.UsmUserData("user")  # S509
    |
 
+
 S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure.
   --> S509.py:17:1
    |
@@ -50,6 +43,7 @@ S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv`
 18 | pysnmp.hlapi.auth.UsmUserData("user")  # S509
    |
 
+
 S509 You should not use SNMPv3 without encryption. `noAuthNoPriv` & `authNoPriv` is insecure.
   --> S509.py:18:1
    |

crates/ruff_linter/src/rules/flake8_pie/rules/unnecessary_placeholder.rs

@@ -1,8 +1,6 @@
 use ruff_macros::{ViolationMetadata, derive_message_formats};
-use ruff_python_ast::helpers::map_subscript;
 use ruff_python_ast::whitespace::trailing_comment_start_offset;
 use ruff_python_ast::{Expr, ExprStringLiteral, Stmt, StmtExpr};
-use ruff_python_semantic::{ScopeKind, SemanticModel};
 use ruff_text_size::Ranged;
 
 use crate::checkers::ast::Checker;
@@ -101,7 +99,7 @@ pub(crate) fn unnecessary_placeholder(checker: &Checker, body: &[Stmt]) {
                 // Ellipses are significant in protocol methods and abstract methods.
                 // Specifically, Pyright uses the presence of an ellipsis to indicate that
                 // a method is a stub, rather than a default implementation.
-                if in_protocol_or_abstract_method(checker.semantic()) {
+                if checker.semantic().in_protocol_or_abstract_method() {
                     return;
                 }
                 Placeholder::Ellipsis
@@ -163,21 +161,3 @@ impl std::fmt::Display for Placeholder {
         }
     }
 }
-
-/// Return `true` if the [`SemanticModel`] is in a `typing.Protocol` subclass or an abstract
-/// method.
-fn in_protocol_or_abstract_method(semantic: &SemanticModel) -> bool {
-    semantic.current_scopes().any(|scope| match scope.kind {
-        ScopeKind::Class(class_def) => class_def
-            .bases()
-            .iter()
-            .any(|base| semantic.match_typing_expr(map_subscript(base), "Protocol")),
-        ScopeKind::Function(function_def) => {
-            ruff_python_semantic::analyze::visibility::is_abstract(
-                &function_def.decorator_list,
-                semantic,
-            )
-        }
-        _ => false,
-    })
-}

crates/ruff_linter/src/rules/ruff/mod.rs

@@ -115,6 +115,7 @@ mod tests {
     #[test_case(Rule::NonOctalPermissions, Path::new("RUF064.py"))]
     #[test_case(Rule::LoggingEagerConversion, Path::new("RUF065_0.py"))]
     #[test_case(Rule::LoggingEagerConversion, Path::new("RUF065_1.py"))]
+    #[test_case(Rule::PropertyWithoutReturn, Path::new("RUF066.py"))]
     #[test_case(Rule::RedirectedNOQA, Path::new("RUF101_0.py"))]
     #[test_case(Rule::RedirectedNOQA, Path::new("RUF101_1.py"))]
     #[test_case(Rule::InvalidRuleCode, Path::new("RUF102.py"))]

crates/ruff_linter/src/rules/ruff/rules/mod.rs

@@ -35,6 +35,7 @@ pub(crate) use non_octal_permissions::*;
 pub(crate) use none_not_at_end_of_union::*;
 pub(crate) use parenthesize_chained_operators::*;
 pub(crate) use post_init_default::*;
+pub(crate) use property_without_return::*;
 pub(crate) use pytest_raises_ambiguous_pattern::*;
 pub(crate) use quadratic_list_summation::*;
 pub(crate) use redirected_noqa::*;
@@ -99,6 +100,7 @@ mod non_octal_permissions;
 mod none_not_at_end_of_union;
 mod parenthesize_chained_operators;
 mod post_init_default;
+mod property_without_return;
 mod pytest_raises_ambiguous_pattern;
 mod quadratic_list_summation;
 mod redirected_noqa;

crates/ruff_linter/src/rules/ruff/rules/property_without_return.rs

@@ -0,0 +1,119 @@
+use ruff_macros::{ViolationMetadata, derive_message_formats};
+use ruff_python_ast::identifier::Identifier;
+use ruff_python_ast::visitor::{Visitor, walk_expr, walk_stmt};
+use ruff_python_ast::{Expr, Stmt, StmtFunctionDef};
+use ruff_python_semantic::analyze::{function_type, visibility};
+
+use crate::checkers::ast::Checker;
+use crate::{FixAvailability, Violation};
+
+/// ## What it does
+/// Detects class `@property` methods that does not have a `return` statement.
+///
+/// ## Why is this bad?
+/// Property methods are expected to return a computed value, a missing return in a property usually indicates an implementation mistake.
+///
+/// ## Example
+/// ```python
+/// class User:
+///     @property
+///     def full_name(self):
+///         f"{self.first_name} {self.last_name}"
+/// ```
+///
+/// Use instead:
+/// ```python
+/// class User:
+///     @property
+///     def full_name(self):
+///         return f"{self.first_name} {self.last_name}"
+/// ```
+///
+/// ## References
+/// - [Python documentation: The property class](https://docs.python.org/3/library/functions.html#property)
+#[derive(ViolationMetadata)]
+#[violation_metadata(preview_since = "0.14.7")]
+pub(crate) struct PropertyWithoutReturn {
+    name: String,
+}
+
+impl Violation for PropertyWithoutReturn {
+    const FIX_AVAILABILITY: FixAvailability = FixAvailability::None;
+
+    #[derive_message_formats]
+    fn message(&self) -> String {
+        let Self { name } = self;
+        format!("`{name}` is a property without a `return` statement")
+    }
+}
+
+/// RUF066
+pub(crate) fn property_without_return(checker: &Checker, function_def: &StmtFunctionDef) {
+    let semantic = checker.semantic();
+
+    if checker.source_type.is_stub() || semantic.in_protocol_or_abstract_method() {
+        return;
+    }
+
+    let StmtFunctionDef {
+        decorator_list,
+        body,
+        name,
+        ..
+    } = function_def;
+
+    if !visibility::is_property(decorator_list, [], semantic)
+        || visibility::is_overload(decorator_list, semantic)
+        || function_type::is_stub(function_def, semantic)
+    {
+        return;
+    }
+
+    let mut visitor = PropertyVisitor::default();
+    visitor.visit_body(body);
+    if visitor.found {
+        return;
+    }
+
+    checker.report_diagnostic(
+        PropertyWithoutReturn {
+            name: name.to_string(),
+        },
+        function_def.identifier(),
+    );
+}
+
+#[derive(Default)]
+struct PropertyVisitor {
+    found: bool,
+}
+
+// NOTE: We are actually searching for the presence of
+// `yield`/`yield from`/`raise`/`return` statement/expression,
+// as having one of those indicates that there's likely no implementation mistake
+impl Visitor<'_> for PropertyVisitor {
+    fn visit_expr(&mut self, expr: &Expr) {
+        if self.found {
+            return;
+        }
+
+        match expr {
+            Expr::Yield(_) | Expr::YieldFrom(_) => self.found = true,
+            _ => walk_expr(self, expr),
+        }
+    }
+
+    fn visit_stmt(&mut self, stmt: &Stmt) {
+        if self.found {
+            return;
+        }
+
+        match stmt {
+            Stmt::Return(_) | Stmt::Raise(_) => self.found = true,
+            Stmt::FunctionDef(_) => {
+                // Do not recurse into nested functions; they're evaluated separately.
+            }
+            _ => walk_stmt(self, stmt),
+        }
+    }
+}

crates/ruff_linter/src/rules/ruff/snapshots/ruff_linter__rules__ruff__tests__RUF066_RUF066.py.snap

@@ -0,0 +1,31 @@
+---
+source: crates/ruff_linter/src/rules/ruff/mod.rs
+---
+RUF066 `name` is a property without a `return` statement
+ --> RUF066.py:7:9
+  |
+5 | class User:  # Test normal class properties
+6 |     @property
+7 |     def name(self):  # ERROR: No return
+  |         ^^^^
+8 |         f"{self.first_name} {self.last_name}"
+  |
+
+RUF066 `nested` is a property without a `return` statement
+  --> RUF066.py:18:9
+   |
+17 |     @property
+18 |     def nested(self):  # ERROR: Property itself doesn't return
+   |         ^^^^^^
+19 |         def inner():
+20 |             return 0
+   |
+
+RUF066 `prop2` is a property without a `return` statement
+  --> RUF066.py:43:9
+   |
+42 |     @property
+43 |     def prop2(self):  # ERROR: Not returning something (even when we are inside an ABC)
+   |         ^^^^^
+44 |         50
+   |

crates/ruff_python_semantic/src/model.rs

@@ -3,12 +3,13 @@ use std::path::Path;
 use bitflags::bitflags;
 use rustc_hash::FxHashMap;
 
-use ruff_python_ast::helpers::from_relative_import;
+use ruff_python_ast::helpers::{from_relative_import, map_subscript};
 use ruff_python_ast::name::{QualifiedName, UnqualifiedName};
 use ruff_python_ast::{self as ast, Expr, ExprContext, PySourceType, Stmt};
 use ruff_text_size::{Ranged, TextRange, TextSize};
 
 use crate::Imported;
+use crate::analyze::visibility;
 use crate::binding::{
     Binding, BindingFlags, BindingId, BindingKind, Bindings, Exceptions, FromImport, Import,
     SubmoduleImport,
@@ -2153,6 +2154,21 @@ impl<'a> SemanticModel<'a> {
             function.range() == function_def.range()
         })
     }
+
+    /// Return `true` if the model is in a `typing.Protocol` subclass or an abstract
+    /// method.
+    pub fn in_protocol_or_abstract_method(&self) -> bool {
+        self.current_scopes().any(|scope| match scope.kind {
+            ScopeKind::Class(class_def) => class_def
+                .bases()
+                .iter()
+                .any(|base| self.match_typing_expr(map_subscript(base), "Protocol")),
+            ScopeKind::Function(function_def) => {
+                visibility::is_abstract(&function_def.decorator_list, self)
+            }
+            _ => false,
+        })
+    }
 }
 
 pub struct ShadowedBinding {

crates/ty/docs/rules.md

@@ -39,7 +39,7 @@ def test(): -> "int":
 Default level: <a href="../rules.md#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#L126" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L131" target="_blank">View source</a>
 </small>
 
 
@@ -63,7 +63,7 @@ Calling a non-callable object will raise a `TypeError` at runtime.
 Default level: <a href="../rules.md#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#L170" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L175" target="_blank">View source</a>
 </small>
 
 
@@ -95,7 +95,7 @@ f(int)  # error
 Default level: <a href="../rules.md#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#L196" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L201" target="_blank">View source</a>
 </small>
 
 
@@ -126,7 +126,7 @@ a = 1
 Default level: <a href="../rules.md#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#L221" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L226" target="_blank">View source</a>
 </small>
 
 
@@ -158,7 +158,7 @@ class C(A, B): ...
 Default level: <a href="../rules.md#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#L247" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L252" target="_blank">View source</a>
 </small>
 
 
@@ -184,13 +184,41 @@ class B(A): ...
 
 [method resolution order]: https://docs.python.org/3/glossary.html#term-method-resolution-order
 
+## `cyclic-type-alias-definition`
+
+<small>
+Default level: <a href="../rules.md#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#L278" target="_blank">View source</a>
+</small>
+
+
+**What it does**
+
+Checks for type alias definitions that (directly or mutually) refer to themselves.
+
+**Why is it bad?**
+
+Although it is permitted to define a recursive type alias, it is not meaningful
+to have a type alias whose expansion can only result in itself, and is therefore not allowed.
+
+**Examples**
+
+```python
+type Itself = Itself
+
+type A = B
+type B = A
+```
+
 ## `duplicate-base`
 
 <small>
 Default level: <a href="../rules.md#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#L312" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L339" target="_blank">View source</a>
 </small>
 
 
@@ -217,7 +245,7 @@ class B(A, A): ...
 Default level: <a href="../rules.md#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#L333" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L360" target="_blank">View source</a>
 </small>
 
 
@@ -329,7 +357,7 @@ def test(): -> "Literal[5]":
 Default level: <a href="../rules.md#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#L537" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L564" target="_blank">View source</a>
 </small>
 
 
@@ -359,7 +387,7 @@ class C(A, B): ...
 Default level: <a href="../rules.md#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#L561" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L588" target="_blank">View source</a>
 </small>
 
 
@@ -385,7 +413,7 @@ t[3]  # IndexError: tuple index out of range
 Default level: <a href="../rules.md#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#L365" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L392" target="_blank">View source</a>
 </small>
 
 
@@ -474,7 +502,7 @@ an atypical memory layout.
 Default level: <a href="../rules.md#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#L615" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L642" target="_blank">View source</a>
 </small>
 
 
@@ -501,7 +529,7 @@ func("foo")  # error: [invalid-argument-type]
 Default level: <a href="../rules.md#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#L655" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L682" target="_blank">View source</a>
 </small>
 
 
@@ -529,7 +557,7 @@ a: int = ''
 Default level: <a href="../rules.md#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#L1814" 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>
 
 
@@ -563,7 +591,7 @@ C.instance_var = 3  # error: Cannot assign to instance variable
 Default level: <a href="../rules.md#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#L677" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L704" target="_blank">View source</a>
 </small>
 
 
@@ -599,7 +627,7 @@ asyncio.run(main())
 Default level: <a href="../rules.md#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#L707" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L734" target="_blank">View source</a>
 </small>
 
 
@@ -623,7 +651,7 @@ class A(42): ...  # error: [invalid-base]
 Default level: <a href="../rules.md#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#L758" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L785" target="_blank">View source</a>
 </small>
 
 
@@ -650,7 +678,7 @@ with 1:
 Default level: <a href="../rules.md#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#L779" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L806" target="_blank">View source</a>
 </small>
 
 
@@ -679,7 +707,7 @@ a: str
 Default level: <a href="../rules.md#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#L802" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L829" target="_blank">View source</a>
 </small>
 
 
@@ -717,13 +745,55 @@ except ZeroDivisionError:
 
  This rule corresponds to Ruff's [`except-with-non-exception-classes` (`B030`)](https://docs.astral.sh/ruff/rules/except-with-non-exception-classes)
 
+## `invalid-explicit-override`
+
+<small>
+Default level: <a href="../rules.md#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#L1574" target="_blank">View source</a>
+</small>
+
+
+**What it does**
+
+Checks for methods that are decorated with `@override` but do not override any method in a superclass.
+
+**Why is this bad?**
+
+Decorating a method with `@override` declares to the type checker that the intention is that it should
+override a method from a superclass.
+
+**Example**
+
+
+```python
+from typing import override
+
+class A:
+    @override
+    def foo(self): ...  # Error raised here
+
+class B(A):
+    @override
+    def ffooo(self): ...  # Error raised here
+
+class C:
+    @override
+    def __repr__(self): ...  # fine: overrides `object.__repr__`
+
+class D(A):
+    @override
+    def foo(self): ...  # fine: overrides `A.foo`
+```
+
 ## `invalid-generic-class`
 
 <small>
 Default level: <a href="../rules.md#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#L838" 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>
 
 
@@ -756,7 +826,7 @@ class C[U](Generic[T]): ...
 Default level: <a href="../rules.md#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#L582" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L609" target="_blank">View source</a>
 </small>
 
 
@@ -795,7 +865,7 @@ carol = Person(name="Carol", age=25)  # typo!
 Default level: <a href="../rules.md#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#L864" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L891" target="_blank">View source</a>
 </small>
 
 
@@ -830,7 +900,7 @@ def f(t: TypeVar("U")): ...
 Default level: <a href="../rules.md#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#L961" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L988" target="_blank">View source</a>
 </small>
 
 
@@ -864,7 +934,7 @@ class B(metaclass=f): ...
 Default level: <a href="../rules.md#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#L1942" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L2005" target="_blank">View source</a>
 </small>
 
 
@@ -950,7 +1020,7 @@ and `__ne__` methods accept `object` as their second argument.
 Default level: <a href="../rules.md#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#L511" target="_blank">View source</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>
 </small>
 
 
@@ -982,7 +1052,7 @@ TypeError: can only inherit from a NamedTuple type and Generic
 Default level: <a href="../rules.md#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#L937" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L964" target="_blank">View source</a>
 </small>
 
 
@@ -1012,7 +1082,7 @@ Baz = NewType("Baz", int | str)  # error: invalid base for `typing.NewType`
 Default level: <a href="../rules.md#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#L988" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1015" target="_blank">View source</a>
 </small>
 
 
@@ -1062,7 +1132,7 @@ def foo(x: int) -> int: ...
 Default level: <a href="../rules.md#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#L1087" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1114" target="_blank">View source</a>
 </small>
 
 
@@ -1088,7 +1158,7 @@ def f(a: int = ''): ...
 Default level: <a href="../rules.md#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#L892" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L919" target="_blank">View source</a>
 </small>
 
 
@@ -1119,7 +1189,7 @@ P2 = ParamSpec("S2")  # error: ParamSpec name must match the variable it's assig
 Default level: <a href="../rules.md#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#L447" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L474" target="_blank">View source</a>
 </small>
 
 
@@ -1153,7 +1223,7 @@ TypeError: Protocols can only inherit from other protocols, got <class 'int'>
 Default level: <a href="../rules.md#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#L1107" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1134" target="_blank">View source</a>
 </small>
 
 
@@ -1202,7 +1272,7 @@ def g():
 Default level: <a href="../rules.md#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#L636" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L663" target="_blank">View source</a>
 </small>
 
 
@@ -1227,7 +1297,7 @@ def func() -> int:
 Default level: <a href="../rules.md#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#L1150" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1177" target="_blank">View source</a>
 </small>
 
 
@@ -1285,7 +1355,7 @@ TODO #14889
 Default level: <a href="../rules.md#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#L916" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L943" target="_blank">View source</a>
 </small>
 
 
@@ -1312,7 +1382,7 @@ NewAlias = TypeAliasType(get_name(), int)        # error: TypeAliasType name mus
 Default level: <a href="../rules.md#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#L1189" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1216" target="_blank">View source</a>
 </small>
 
 
@@ -1342,7 +1412,7 @@ TYPE_CHECKING = ''
 Default level: <a href="../rules.md#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#L1213" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1240" target="_blank">View source</a>
 </small>
 
 
@@ -1372,7 +1442,7 @@ b: Annotated[int]  # `Annotated` expects at least two arguments
 Default level: <a href="../rules.md#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#L1265" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1292" target="_blank">View source</a>
 </small>
 
 
@@ -1406,7 +1476,7 @@ f(10)  # Error
 Default level: <a href="../rules.md#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#L1237" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1264" target="_blank">View source</a>
 </small>
 
 
@@ -1440,7 +1510,7 @@ class C:
 Default level: <a href="../rules.md#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#L1293" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1320" target="_blank">View source</a>
 </small>
 
 
@@ -1475,7 +1545,7 @@ T = TypeVar('T', bound=str)  # valid bound TypeVar
 Default level: <a href="../rules.md#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#L1322" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1349" target="_blank">View source</a>
 </small>
 
 
@@ -1500,7 +1570,7 @@ func()  # TypeError: func() missing 1 required positional argument: 'x'
 Default level: <a href="../rules.md#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#L1915" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1978" target="_blank">View source</a>
 </small>
 
 
@@ -1533,7 +1603,7 @@ alice["age"]  # KeyError
 Default level: <a href="../rules.md#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#L1341" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1368" target="_blank">View source</a>
 </small>
 
 
@@ -1562,7 +1632,7 @@ func("string")  # error: [no-matching-overload]
 Default level: <a href="../rules.md#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%20non-subscriptable" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1364" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1391" target="_blank">View source</a>
 </small>
 
 
@@ -1586,7 +1656,7 @@ Subscripting an object that does not support it will raise a `TypeError` at runt
 Default level: <a href="../rules.md#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#L1382" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1409" target="_blank">View source</a>
 </small>
 
 
@@ -1612,7 +1682,7 @@ for i in 34:  # TypeError: 'int' object is not iterable
 Default level: <a href="../rules.md#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#L1433" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1460" target="_blank">View source</a>
 </small>
 
 
@@ -1639,7 +1709,7 @@ f(1, x=2)  # Error raised here
 Default level: <a href="../rules.md#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#L1668" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1731" target="_blank">View source</a>
 </small>
 
 
@@ -1697,7 +1767,7 @@ def test(): -> "int":
 Default level: <a href="../rules.md#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#L1790" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1853" target="_blank">View source</a>
 </small>
 
 
@@ -1727,7 +1797,7 @@ static_assert(int(2.0 * 3.0) == 6)  # error: does not have a statically known tr
 Default level: <a href="../rules.md#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#L1524" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1551" target="_blank">View source</a>
 </small>
 
 
@@ -1756,7 +1826,7 @@ class B(A): ...  # Error raised here
 Default level: <a href="../rules.md#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#L1569" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1632" target="_blank">View source</a>
 </small>
 
 
@@ -1783,7 +1853,7 @@ f("foo")  # Error raised here
 Default level: <a href="../rules.md#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#L1547" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1610" target="_blank">View source</a>
 </small>
 
 
@@ -1811,7 +1881,7 @@ def _(x: int):
 Default level: <a href="../rules.md#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#L1590" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1653" target="_blank">View source</a>
 </small>
 
 
@@ -1857,7 +1927,7 @@ class A:
 Default level: <a href="../rules.md#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#L1647" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1710" target="_blank">View source</a>
 </small>
 
 
@@ -1884,7 +1954,7 @@ f(x=1, y=2)  # Error raised here
 Default level: <a href="../rules.md#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#L1689" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1752" target="_blank">View source</a>
 </small>
 
 
@@ -1912,7 +1982,7 @@ A().foo  # AttributeError: 'A' object has no attribute 'foo'
 Default level: <a href="../rules.md#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#L1711" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1774" target="_blank">View source</a>
 </small>
 
 
@@ -1937,7 +2007,7 @@ import foo  # ModuleNotFoundError: No module named 'foo'
 Default level: <a href="../rules.md#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#L1730" 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>
 
 
@@ -1962,7 +2032,7 @@ print(x)  # NameError: name 'x' is not defined
 Default level: <a href="../rules.md#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#L1402" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1429" target="_blank">View source</a>
 </small>
 
 
@@ -1999,7 +2069,7 @@ b1 < b2 < b1  # exception raised here
 Default level: <a href="../rules.md#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#L1749" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1812" target="_blank">View source</a>
 </small>
 
 
@@ -2027,7 +2097,7 @@ A() + A()  # TypeError: unsupported operand type(s) for +: 'A' and 'A'
 Default level: <a href="../rules.md#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#L1771" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1834" target="_blank">View source</a>
 </small>
 
 
@@ -2052,7 +2122,7 @@ l[1:10:0]  # ValueError: slice step cannot be zero
 Default level: <a href="../rules.md#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#L476" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L503" target="_blank">View source</a>
 </small>
 
 
@@ -2093,7 +2163,7 @@ class SubProto(BaseProto, Protocol):
 Default level: <a href="../rules.md#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#L291" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L318" target="_blank">View source</a>
 </small>
 
 
@@ -2120,7 +2190,7 @@ old_func()  # emits [deprecated] diagnostic
 Default level: <a href="../rules.md#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%20ignore-comment-unknown-rule" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Fsuppression.rs#L40" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Fsuppression.rs#L47" target="_blank">View source</a>
 </small>
 
 
@@ -2151,7 +2221,7 @@ a = 20 / 0  # ty: ignore[division-by-zero]
 Default level: <a href="../rules.md#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%20invalid-ignore-comment" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Fsuppression.rs#L65" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Fsuppression.rs#L72" target="_blank">View source</a>
 </small>
 
 
@@ -2181,7 +2251,7 @@ a = 20 / 0  # type: ignore
 Default level: <a href="../rules.md#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#L1454" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1481" target="_blank">View source</a>
 </small>
 
 
@@ -2209,7 +2279,7 @@ A.c  # AttributeError: type object 'A' has no attribute 'c'
 Default level: <a href="../rules.md#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#L144" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L149" target="_blank">View source</a>
 </small>
 
 
@@ -2241,7 +2311,7 @@ A()[0]  # TypeError: 'A' object is not subscriptable
 Default level: <a href="../rules.md#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-import" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1476" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1503" target="_blank">View source</a>
 </small>
 
 
@@ -2273,7 +2343,7 @@ from module import a  # ImportError: cannot import name 'a' from 'module'
 Default level: <a href="../rules.md#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#L1842" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1905" target="_blank">View source</a>
 </small>
 
 
@@ -2300,7 +2370,7 @@ cast(int, f())  # Redundant
 Default level: <a href="../rules.md#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#L1629" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1692" target="_blank">View source</a>
 </small>
 
 
@@ -2324,7 +2394,7 @@ reveal_type(1)  # NameError: name 'reveal_type' is not defined
 Default level: <a href="../rules.md#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#L1863" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1926" target="_blank">View source</a>
 </small>
 
 
@@ -2382,7 +2452,7 @@ def g():
 Default level: <a href="../rules.md#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#L725" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L752" target="_blank">View source</a>
 </small>
 
 
@@ -2421,7 +2491,7 @@ class D(C): ...  # error: [unsupported-base]
 Default level: <a href="../rules.md#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#L1031" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1058" target="_blank">View source</a>
 </small>
 
 
@@ -2484,7 +2554,7 @@ def foo(x: int | str) -> int | str:
 Default level: <a href="../rules.md#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#L273" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L300" target="_blank">View source</a>
 </small>
 
 
@@ -2508,7 +2578,7 @@ Dividing by zero raises a `ZeroDivisionError` at runtime.
 Default level: <a href="../rules.md#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#L1502" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Ftypes%2Fdiagnostic.rs#L1529" target="_blank">View source</a>
 </small>
 
 
@@ -2536,7 +2606,7 @@ print(x)  # NameError: name 'x' is not defined
 Default level: <a href="../rules.md#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%20unused-ignore-comment" target="_blank">Related issues</a> ·
-<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Fsuppression.rs#L15" target="_blank">View source</a>
+<a href="https://github.com/astral-sh/ruff/blob/main/crates%2Fty_python_semantic%2Fsrc%2Fsuppression.rs#L22" target="_blank">View source</a>
 </small>
 
 

crates/ty/src/lib.rs

@@ -313,7 +313,8 @@ impl MainLoop {
                     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());
+                        .color(colored::control::SHOULD_COLORIZE.should_colorize())
+                        .show_fix_diff(true);
 
                     if check_revision == revision {
                         if db.project().files(db).is_empty() {

crates/ty/tests/cli/python_environment.rs

@@ -37,7 +37,8 @@ fn config_override_python_version() -> anyhow::Result<()> {
     5 | print(sys.last_exc)
       |       ^^^^^^^^^^^^
       |
-    info: Python 3.11 was assumed when accessing `last_exc`
+    info: The member may be available on other Python versions or platforms
+    info: Python 3.11 was assumed when resolving the `last_exc` attribute
      --> pyproject.toml:3:18
       |
     2 | [tool.ty.environment]
@@ -1179,6 +1180,8 @@ fn defaults_to_a_new_python_version() -> anyhow::Result<()> {
             import os
 
             os.grantpt(1) # only available on unix, Python 3.13 or newer
+
+            from typing import LiteralString  # added in Python 3.11
             "#,
         ),
     ])?;
@@ -1194,8 +1197,11 @@ fn defaults_to_a_new_python_version() -> anyhow::Result<()> {
     3 |
     4 | os.grantpt(1) # only available on unix, Python 3.13 or newer
       | ^^^^^^^^^^
+    5 |
+    6 | from typing import LiteralString  # added in Python 3.11
       |
-    info: Python 3.10 was assumed when accessing `grantpt`
+    info: The member may be available on other Python versions or platforms
+    info: Python 3.10 was assumed when resolving the `grantpt` attribute
      --> ty.toml:3:18
       |
     2 | [environment]
@@ -1205,7 +1211,26 @@ fn defaults_to_a_new_python_version() -> anyhow::Result<()> {
       |
     info: rule `unresolved-attribute` is enabled by default
 
-    Found 1 diagnostic
+    error[unresolved-import]: Module `typing` has no member `LiteralString`
+     --> main.py:6:20
+      |
+    4 | os.grantpt(1) # only available on unix, Python 3.13 or newer
+    5 |
+    6 | from typing import LiteralString  # added in Python 3.11
+      |                    ^^^^^^^^^^^^^
+      |
+    info: The member may be available on other Python versions or platforms
+    info: Python 3.10 was assumed when resolving imports
+     --> ty.toml:3:18
+      |
+    2 | [environment]
+    3 | python-version = "3.10"
+      |                  ^^^^^^ Python 3.10 assumed due to this configuration setting
+    4 | python-platform = "linux"
+      |
+    info: rule `unresolved-import` is enabled by default
+
+    Found 2 diagnostics
 
     ----- stderr -----
     "#);
@@ -1225,6 +1250,8 @@ fn defaults_to_a_new_python_version() -> anyhow::Result<()> {
             import os
 
             os.grantpt(1) # only available on unix, Python 3.13 or newer
+
+            from typing import LiteralString  # added in Python 3.11
             "#,
         ),
     ])?;

crates/ty_completion_eval/completion-evaluation-tasks.csv

@@ -18,11 +18,11 @@ numpy-array,main.py,1,1
 object-attr-instance-methods,main.py,0,1
 object-attr-instance-methods,main.py,1,1
 pass-keyword-completion,main.py,0,1
-raise-uses-base-exception,main.py,0,2
+raise-uses-base-exception,main.py,0,1
 scope-existing-over-new-import,main.py,0,1
 scope-prioritize-closer,main.py,0,2
 scope-simple-long-identifier,main.py,0,1
 tstring-completions,main.py,0,1
 ty-extensions-lower-stdlib,main.py,0,8
 type-var-typing-over-ast,main.py,0,3
-type-var-typing-over-ast,main.py,1,279
+type-var-typing-over-ast,main.py,1,278

crates/ty_ide/src/completion.rs

@@ -9,9 +9,10 @@ use ruff_python_ast::name::Name;
 use ruff_python_codegen::Stylist;
 use ruff_python_parser::{Token, TokenAt, TokenKind, Tokens};
 use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
+use ty_python_semantic::types::UnionType;
 use ty_python_semantic::{
-    Completion as SemanticCompletion, ModuleName, NameKind, SemanticModel,
-    types::{CycleDetector, Type},
+    Completion as SemanticCompletion, KnownModule, ModuleName, NameKind, SemanticModel,
+    types::{CycleDetector, KnownClass, Type},
 };
 
 use crate::docstring::Docstring;
@@ -82,6 +83,31 @@ impl<'db> Completions<'db> {
     fn force_add(&mut self, completion: Completion<'db>) {
         self.items.push(completion);
     }
+
+    /// Tags completions with whether they are known to be usable in
+    /// a `raise` context.
+    ///
+    /// It's possible that some completions are usable in a `raise`
+    /// but aren't marked by this method. That is, false negatives are
+    /// possible but false positives are not.
+    fn tag_raisable(&mut self) {
+        let raisable_type = UnionType::from_elements(
+            self.db,
+            [
+                KnownClass::BaseException.to_subclass_of(self.db),
+                KnownClass::BaseException.to_instance(self.db),
+            ],
+        );
+        for item in &mut self.items {
+            let Some(ty) = item.ty else { continue };
+            item.is_definitively_raisable = ty.is_assignable_to(self.db, raisable_type);
+        }
+    }
+
+    /// Removes any completion that doesn't satisfy the given predicate.
+    fn retain(&mut self, predicate: impl FnMut(&Completion<'_>) -> bool) {
+        self.items.retain(predicate);
+    }
 }
 
 impl<'db> Extend<SemanticCompletion<'db>> for Completions<'db> {
@@ -153,6 +179,13 @@ 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.
+    ///
+    /// 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,
     /// The documentation associated with this item, if
     /// available.
     pub documentation: Option<Docstring>,
@@ -177,6 +210,7 @@ impl<'db> Completion<'db> {
             import: None,
             builtin: semantic.builtin,
             is_type_check_only,
+            is_definitively_raisable: false,
             documentation,
         }
     }
@@ -257,6 +291,7 @@ impl<'db> Completion<'db> {
             import: None,
             builtin: false,
             is_type_check_only: false,
+            is_definitively_raisable: false,
             documentation: None,
         }
     }
@@ -271,6 +306,7 @@ impl<'db> Completion<'db> {
             import: None,
             builtin: true,
             is_type_check_only: false,
+            is_definitively_raisable: false,
             documentation: None,
         }
     }
@@ -364,6 +400,20 @@ pub fn completion<'db>(
         }
     }
 
+    if is_raising_exception(tokens) {
+        completions.tag_raisable();
+
+        // As a special case, and because it's a common footgun, we
+        // specifically disallow `NotImplemented` in this context.
+        // `NotImplementedError` should be used instead. So if we can
+        // definitively detect `NotImplemented`, then we can safely
+        // omit it from suggestions.
+        completions.retain(|item| {
+            let Some(ty) = item.ty else { return true };
+            !ty.is_notimplemented(db)
+        });
+    }
+
     completions.into_completions()
 }
 
@@ -427,7 +477,8 @@ fn add_unimported_completions<'db>(
     let members = importer.members_in_scope_at(scoped.node, scoped.node.start());
 
     for symbol in all_symbols(db, &completions.query) {
-        if symbol.module.file(db) == Some(file) {
+        if symbol.module.file(db) == Some(file) || symbol.module.is_known(db, KnownModule::Builtins)
+        {
             continue;
         }
 
@@ -450,6 +501,7 @@ 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,
             documentation: None,
         });
     }
@@ -1263,7 +1315,8 @@ fn find_typed_text(
     if last.end() < offset || last.range().is_empty() {
         return None;
     }
-    Some(source[last.range()].to_string())
+    let range = TextRange::new(last.start(), offset);
+    Some(source[range].to_string())
 }
 
 /// Whether the last token is in a place where we should not provide completions.
@@ -1354,10 +1407,52 @@ fn is_in_variable_binding(parsed: &ParsedModuleRef, offset: TextSize, typed: Opt
             type_param.name.range.contains_range(range)
         }
         ast::AnyNodeRef::StmtFor(stmt_for) => stmt_for.target.range().contains_range(range),
+        // The AST does not produce `ast::AnyNodeRef::Parameter` nodes for keywords
+        // or otherwise invalid syntax. Rather they are captured in a
+        // `ast::AnyNodeRef::Parameters` node as "empty space". To ensure
+        // we still suppress suggestions even when the syntax is technically
+        // invalid we extract the token under the cursor and check if it makes
+        // up that "empty space" inside the Parameters Node. If it does, we know
+        // that we are still binding variables, just that the current state is
+        // syntatically invalid. Hence we suppress autocomplete suggestons
+        // also in those cases.
+        ast::AnyNodeRef::Parameters(params) => {
+            if !params.range.contains_range(range) {
+                return false;
+            }
+            params
+                .iter()
+                .map(|param| param.range())
+                .all(|r| !r.contains_range(range))
+        }
         _ => false,
     })
 }
 
+/// Returns true when the cursor is after a `raise` keyword.
+fn is_raising_exception(tokens: &[Token]) -> bool {
+    /// The maximum number of tokens we're willing to
+    /// look-behind to find a `raise` keyword.
+    const LIMIT: usize = 10;
+
+    // This only looks for things like `raise foo.bar.baz.qu<CURSOR>`.
+    // Technically, any kind of expression is allowed after `raise`.
+    // But we may not always want to treat it specially. So we're
+    // rather conservative about what we consider "raising an
+    // exception" to be for the purposes of completions. The failure
+    // mode here is that we may wind up suggesting things that
+    // shouldn't be raised. The benefit is that when this heuristic
+    // does work, we won't suggest things that shouldn't be raised.
+    for token in tokens.iter().rev().take(LIMIT) {
+        match token.kind() {
+            TokenKind::Name | TokenKind::Dot => continue,
+            TokenKind::Raise => return true,
+            _ => return false,
+        }
+    }
+    false
+}
+
 /// Order completions according to the following rules:
 ///
 /// 1) Names with no underscore prefix
@@ -1370,8 +1465,16 @@ fn is_in_variable_binding(parsed: &ParsedModuleRef, offset: TextSize, typed: Opt
 /// This has the effect of putting all dunder attributes after "normal"
 /// attributes, and all single-underscore attributes after dunder attributes.
 fn compare_suggestions(c1: &Completion, c2: &Completion) -> Ordering {
-    fn key<'a>(completion: &'a Completion) -> (bool, bool, bool, NameKind, bool, &'a Name) {
+    fn key<'a>(completion: &'a Completion) -> (bool, bool, bool, bool, NameKind, bool, &'a Name) {
         (
+            // This is only true when we are both in a `raise` context
+            // *and* we know this suggestion is definitively usable
+            // in a `raise` context. So we should sort these before
+            // anything else.
+            !completion.is_definitively_raisable,
+            // When `None`, a completion is for something in the
+            // current module, which we should generally prefer over
+            // something from outside the module.
             completion.module_name.is_some(),
             // At time of writing (2025-11-11), keyword completions
             // are classified as builtins, which makes them sort after
@@ -1549,6 +1652,21 @@ mod tests {
         );
     }
 
+    #[test]
+    fn inside_token() {
+        let test = completion_test_builder(
+            "\
+foo_bar_baz = 1
+x = foo<CURSOR>bad
+",
+        );
+
+        assert_snapshot!(
+            test.skip_builtins().build().snapshot(),
+            @"foo_bar_baz",
+        );
+    }
+
     #[test]
     fn type_keyword_dedup() {
         let test = completion_test_builder(
@@ -5263,6 +5381,45 @@ def foo(p<CURSOR>
         );
     }
 
+    #[test]
+    fn no_completions_in_function_param_keyword() {
+        let builder = completion_test_builder(
+            "\
+def foo(in<CURSOR>
+",
+        );
+        assert_snapshot!(
+            builder.build().snapshot(),
+            @"<No completions found>",
+        );
+    }
+
+    #[test]
+    fn no_completions_in_function_param_multi_keyword() {
+        let builder = completion_test_builder(
+            "\
+def foo(param, in<CURSOR>
+",
+        );
+        assert_snapshot!(
+            builder.build().snapshot(),
+            @"<No completions found>",
+        );
+    }
+
+    #[test]
+    fn no_completions_in_function_param_multi_keyword_middle() {
+        let builder = completion_test_builder(
+            "\
+def foo(param, in<CURSOR>, param_two
+",
+        );
+        assert_snapshot!(
+            builder.build().snapshot(),
+            @"<No completions found>",
+        );
+    }
+
     #[test]
     fn no_completions_in_function_type_param() {
         let builder = completion_test_builder(

crates/ty_ide/src/doc_highlights.rs

@@ -3,6 +3,7 @@ use crate::references::{ReferencesMode, references};
 use crate::{Db, ReferenceTarget};
 use ruff_db::files::File;
 use ruff_text_size::TextSize;
+use ty_python_semantic::SemanticModel;
 
 /// Find all document highlights for a symbol at the given position.
 /// Document highlights are limited to the current file only.
@@ -13,9 +14,10 @@ pub fn document_highlights(
 ) -> Option<Vec<ReferenceTarget>> {
     let parsed = ruff_db::parsed::parsed_module(db, file);
     let module = parsed.load(db);
+    let model = SemanticModel::new(db, file);
 
     // Get the definitions for the symbol at the cursor position
-    let goto_target = find_goto_target(&module, offset)?;
+    let goto_target = find_goto_target(&model, &module, offset)?;
 
     // Use DocumentHighlights mode which limits search to current file only
     references(db, file, &goto_target, ReferencesMode::DocumentHighlights)

crates/ty_ide/src/goto.rs

@@ -190,6 +190,24 @@ pub(crate) enum GotoTarget<'a> {
         /// The call of the callable
         call: &'a ast::ExprCall,
     },
+
+    /// Go to on a sub-expression of a string annotation's sub-AST
+    ///
+    /// ```py
+    /// x: "int | None"
+    ///           ^^^^
+    /// ```
+    ///
+    /// This is equivalent to `GotoTarget::Expression` but the expression
+    /// isn't actually in the AST.
+    StringAnnotationSubexpr {
+        /// The string literal that is a string annotation.
+        string_expr: &'a ast::ExprStringLiteral,
+        /// The range to query in the sub-AST for the sub-expression.
+        subrange: TextRange,
+        /// If the expression is a Name of some kind this is the name (just a cached result).
+        name: Option<String>,
+    },
 }
 
 /// The resolved definitions for a `GotoTarget`
@@ -227,7 +245,7 @@ impl<'db> DefinitionsOrTargets<'db> {
     /// In this case it basically returns exactly what was found.
     pub(crate) fn declaration_targets(
         self,
-        db: &'db dyn crate::Db,
+        db: &'db dyn ty_python_semantic::Db,
     ) -> Option<crate::NavigationTargets> {
         match self {
             DefinitionsOrTargets::Definitions(definitions) => {
@@ -243,7 +261,7 @@ impl<'db> DefinitionsOrTargets<'db> {
     /// if the definition we have is found in a stub file.
     pub(crate) fn definition_targets(
         self,
-        db: &'db dyn crate::Db,
+        db: &'db dyn ty_python_semantic::Db,
     ) -> Option<crate::NavigationTargets> {
         match self {
             DefinitionsOrTargets::Definitions(definitions) => {
@@ -313,6 +331,32 @@ impl GotoTarget<'_> {
                 let module = import_name(module_name, *component_index);
                 model.resolve_module_type(Some(module), *level)?
             }
+            GotoTarget::StringAnnotationSubexpr {
+                string_expr,
+                subrange,
+                ..
+            } => {
+                let (subast, _submodel) = model.enter_string_annotation(string_expr)?;
+                let submod = subast.syntax();
+                let subnode = covering_node(submod.into(), *subrange).node();
+
+                // The type checker knows the type of the full annotation but nothing else
+                if AnyNodeRef::from(&*submod.body) == subnode {
+                    string_expr.inferred_type(model)
+                } else {
+                    // TODO: force the typechecker to tell us its secrets
+                    // (it computes but then immediately discards these types)
+                    return None;
+                }
+            }
+            GotoTarget::BinOp { expression, .. } => {
+                let (_, ty) = ty_python_semantic::definitions_for_bin_op(model, expression)?;
+                ty
+            }
+            GotoTarget::UnaryOp { expression, .. } => {
+                let (_, ty) = ty_python_semantic::definitions_for_unary_op(model, expression)?;
+                ty
+            }
             // TODO: Support identifier targets
             GotoTarget::PatternMatchRest(_)
             | GotoTarget::PatternKeywordArgument(_)
@@ -322,16 +366,6 @@ impl GotoTarget<'_> {
             | GotoTarget::TypeParamTypeVarTupleName(_)
             | GotoTarget::NonLocal { .. }
             | GotoTarget::Globals { .. } => return None,
-            GotoTarget::BinOp { expression, .. } => {
-                let (_, ty) =
-                    ty_python_semantic::definitions_for_bin_op(model.db(), model, expression)?;
-                ty
-            }
-            GotoTarget::UnaryOp { expression, .. } => {
-                let (_, ty) =
-                    ty_python_semantic::definitions_for_unary_op(model.db(), model, expression)?;
-                ty
-            }
         };
 
         Some(ty)
@@ -343,7 +377,7 @@ impl GotoTarget<'_> {
         model: &SemanticModel,
     ) -> Option<String> {
         if let GotoTarget::Call { call, .. } = self {
-            call_type_simplified_by_overloads(model.db(), model, call)
+            call_type_simplified_by_overloads(model, call)
         } else {
             None
         }
@@ -367,14 +401,9 @@ impl GotoTarget<'_> {
         alias_resolution: ImportAliasResolution,
     ) -> Option<DefinitionsOrTargets<'db>> {
         use crate::NavigationTarget;
-        let db = model.db();
-        let file = model.file();
-
         match self {
-            GotoTarget::Expression(expression) => {
-                definitions_for_expression(model, expression).map(DefinitionsOrTargets::Definitions)
-            }
-
+            GotoTarget::Expression(expression) => definitions_for_expression(model, *expression)
+                .map(DefinitionsOrTargets::Definitions),
             // For already-defined symbols, they are their own definitions
             GotoTarget::FunctionDef(function) => Some(DefinitionsOrTargets::Definitions(vec![
                 ResolvedDefinition::Definition(function.definition(model)),
@@ -395,8 +424,7 @@ impl GotoTarget<'_> {
                 let symbol_name = alias.name.as_str();
                 Some(DefinitionsOrTargets::Definitions(
                     definitions_for_imported_symbol(
-                        db,
-                        file,
+                        model,
                         import_from,
                         symbol_name,
                         alias_resolution,
@@ -423,7 +451,7 @@ impl GotoTarget<'_> {
                     let alias_range = alias.asname.as_ref().unwrap().range;
                     Some(DefinitionsOrTargets::Targets(
                         crate::NavigationTargets::single(NavigationTarget {
-                            file,
+                            file: model.file(),
                             focus_range: alias_range,
                             full_range: alias.range(),
                         }),
@@ -436,7 +464,7 @@ impl GotoTarget<'_> {
                 keyword,
                 call_expression,
             } => Some(DefinitionsOrTargets::Definitions(
-                definitions_for_keyword_argument(db, file, keyword, call_expression),
+                definitions_for_keyword_argument(model, keyword, call_expression),
             )),
 
             // For exception variables, they are their own definitions (like parameters)
@@ -451,7 +479,10 @@ impl GotoTarget<'_> {
                 if let Some(rest_name) = &pattern_mapping.rest {
                     let range = rest_name.range;
                     Some(DefinitionsOrTargets::Targets(
-                        crate::NavigationTargets::single(NavigationTarget::new(file, range)),
+                        crate::NavigationTargets::single(NavigationTarget::new(
+                            model.file(),
+                            range,
+                        )),
                     ))
                 } else {
                     None
@@ -463,7 +494,10 @@ impl GotoTarget<'_> {
                 if let Some(name) = &pattern_as.name {
                     let range = name.range;
                     Some(DefinitionsOrTargets::Targets(
-                        crate::NavigationTargets::single(NavigationTarget::new(file, range)),
+                        crate::NavigationTargets::single(NavigationTarget::new(
+                            model.file(),
+                            range,
+                        )),
                     ))
                 } else {
                     None
@@ -476,7 +510,7 @@ impl GotoTarget<'_> {
             GotoTarget::Call { callable, call } => {
                 let mut definitions = definitions_for_callable(model, call);
                 let expr_definitions =
-                    definitions_for_expression(model, callable).unwrap_or_default();
+                    definitions_for_expression(model, *callable).unwrap_or_default();
                 definitions.extend(expr_definitions);
 
                 if definitions.is_empty() {
@@ -488,19 +522,45 @@ impl GotoTarget<'_> {
 
             GotoTarget::BinOp { expression, .. } => {
                 let (definitions, _) =
-                    ty_python_semantic::definitions_for_bin_op(db, model, expression)?;
+                    ty_python_semantic::definitions_for_bin_op(model, expression)?;
 
                 Some(DefinitionsOrTargets::Definitions(definitions))
             }
 
             GotoTarget::UnaryOp { expression, .. } => {
                 let (definitions, _) =
-                    ty_python_semantic::definitions_for_unary_op(db, model, expression)?;
+                    ty_python_semantic::definitions_for_unary_op(model, expression)?;
 
                 Some(DefinitionsOrTargets::Definitions(definitions))
             }
 
-            _ => None,
+            // String annotations sub-expressions require us to recurse into the sub-AST
+            GotoTarget::StringAnnotationSubexpr {
+                string_expr,
+                subrange,
+                ..
+            } => {
+                let (subast, submodel) = model.enter_string_annotation(string_expr)?;
+                let subexpr = covering_node(subast.syntax().into(), *subrange)
+                    .node()
+                    .as_expr_ref()?;
+                definitions_for_expression(&submodel, subexpr)
+                    .map(DefinitionsOrTargets::Definitions)
+            }
+            GotoTarget::NonLocal { identifier } | GotoTarget::Globals { identifier } => {
+                Some(DefinitionsOrTargets::Definitions(definitions_for_name(
+                    model,
+                    identifier.as_str(),
+                    AnyNodeRef::Identifier(identifier),
+                )))
+            }
+
+            // TODO: implement these
+            GotoTarget::PatternKeywordArgument(..)
+            | GotoTarget::PatternMatchStarName(..)
+            | GotoTarget::TypeParamTypeVarName(..)
+            | GotoTarget::TypeParamParamSpecName(..)
+            | GotoTarget::TypeParamTypeVarTupleName(..) => None,
         }
     }
 
@@ -519,6 +579,7 @@ impl GotoTarget<'_> {
                 ast::ExprRef::Attribute(attr) => Some(Cow::Borrowed(attr.attr.as_str())),
                 _ => None,
             },
+            GotoTarget::StringAnnotationSubexpr { name, .. } => name.as_deref().map(Cow::Borrowed),
             GotoTarget::FunctionDef(function) => Some(Cow::Borrowed(function.name.as_str())),
             GotoTarget::ClassDef(class) => Some(Cow::Borrowed(class.name.as_str())),
             GotoTarget::Parameter(parameter) => Some(Cow::Borrowed(parameter.name.as_str())),
@@ -579,6 +640,7 @@ impl GotoTarget<'_> {
 
     /// Creates a `GotoTarget` from a `CoveringNode` and an offset within the node
     pub(crate) fn from_covering_node<'a>(
+        model: &SemanticModel,
         covering_node: &crate::find_node::CoveringNode<'a>,
         offset: TextSize,
         tokens: &Tokens,
@@ -778,6 +840,31 @@ impl GotoTarget<'_> {
                 Some(GotoTarget::Expression(unary.into()))
             }
 
+            node @ AnyNodeRef::ExprStringLiteral(string_expr) => {
+                // Check if we've clicked on a sub-GotoTarget inside a string annotation's sub-AST
+                if let Some((subast, submodel)) = model.enter_string_annotation(string_expr)
+                    && let Some(GotoTarget::Expression(subexpr)) = find_goto_target_impl(
+                        &submodel,
+                        subast.tokens(),
+                        subast.syntax().into(),
+                        offset,
+                    )
+                {
+                    let name = match subexpr {
+                        ast::ExprRef::Name(name) => Some(name.id.to_string()),
+                        ast::ExprRef::Attribute(attr) => Some(attr.attr.to_string()),
+                        _ => None,
+                    };
+                    Some(GotoTarget::StringAnnotationSubexpr {
+                        string_expr,
+                        subrange: subexpr.range(),
+                        name,
+                    })
+                } else {
+                    node.as_expr_ref().map(GotoTarget::Expression)
+                }
+            }
+
             node => {
                 // Check if this is seemingly a callable being invoked (the `x` in `x(...)`)
                 let parent = covering_node.parent();
@@ -813,6 +900,7 @@ impl Ranged for GotoTarget<'_> {
             GotoTarget::ImportModuleComponent {
                 component_range, ..
             } => *component_range,
+            GotoTarget::StringAnnotationSubexpr { subrange, .. } => *subrange,
             GotoTarget::ImportModuleAlias { alias } => alias.asname.as_ref().unwrap().range,
             GotoTarget::ExceptVariable(except) => except.name.as_ref().unwrap().range,
             GotoTarget::KeywordArgument { keyword, .. } => keyword.arg.as_ref().unwrap().range,
@@ -832,9 +920,9 @@ impl Ranged for GotoTarget<'_> {
 }
 
 /// Converts a collection of `ResolvedDefinition` items into `NavigationTarget` items.
-fn convert_resolved_definitions_to_targets(
-    db: &dyn crate::Db,
-    definitions: Vec<ty_python_semantic::ResolvedDefinition<'_>>,
+fn convert_resolved_definitions_to_targets<'db>(
+    db: &'db dyn ty_python_semantic::Db,
+    definitions: Vec<ty_python_semantic::ResolvedDefinition<'db>>,
 ) -> Vec<crate::NavigationTarget> {
     definitions
         .into_iter()
@@ -869,14 +957,16 @@ fn convert_resolved_definitions_to_targets(
 /// Shared helper to get definitions for an expr (that is presumably a name/attr)
 fn definitions_for_expression<'db>(
     model: &SemanticModel<'db>,
-    expression: &ruff_python_ast::ExprRef<'_>,
+    expression: ruff_python_ast::ExprRef<'_>,
 ) -> Option<Vec<ResolvedDefinition<'db>>> {
     match expression {
-        ast::ExprRef::Name(name) => Some(definitions_for_name(model.db(), model.file(), name)),
+        ast::ExprRef::Name(name) => Some(definitions_for_name(
+            model,
+            name.id.as_str(),
+            expression.into(),
+        )),
         ast::ExprRef::Attribute(attribute) => Some(ty_python_semantic::definitions_for_attribute(
-            model.db(),
-            model.file(),
-            attribute,
+            model, attribute,
         )),
         _ => None,
     }
@@ -887,7 +977,7 @@ fn definitions_for_callable<'db>(
     call: &ast::ExprCall,
 ) -> Vec<ResolvedDefinition<'db>> {
     // Attempt to refine to a specific call
-    let signature_info = call_signature_details(model.db(), model, call);
+    let signature_info = call_signature_details(model, call);
     signature_info
         .into_iter()
         .filter_map(|signature| signature.definition.map(ResolvedDefinition::Definition))
@@ -896,7 +986,7 @@ fn definitions_for_callable<'db>(
 
 /// Shared helper to map and convert resolved definitions into navigation targets.
 fn definitions_to_navigation_targets<'db>(
-    db: &dyn crate::Db,
+    db: &dyn ty_python_semantic::Db,
     stub_mapper: Option<&StubMapper<'db>>,
     mut definitions: Vec<ty_python_semantic::ResolvedDefinition<'db>>,
 ) -> Option<crate::NavigationTargets> {
@@ -911,12 +1001,21 @@ fn definitions_to_navigation_targets<'db>(
     }
 }
 
-pub(crate) fn find_goto_target(
-    parsed: &ParsedModuleRef,
+pub(crate) fn find_goto_target<'a>(
+    model: &'a SemanticModel,
+    parsed: &'a ParsedModuleRef,
     offset: TextSize,
-) -> Option<GotoTarget<'_>> {
-    let token = parsed
-        .tokens()
+) -> Option<GotoTarget<'a>> {
+    find_goto_target_impl(model, parsed.tokens(), parsed.syntax().into(), offset)
+}
+
+pub(crate) fn find_goto_target_impl<'a>(
+    model: &'a SemanticModel,
+    tokens: &'a Tokens,
+    syntax: AnyNodeRef<'a>,
+    offset: TextSize,
+) -> Option<GotoTarget<'a>> {
+    let token = tokens
         .at_offset(offset)
         .max_by_key(|token| match token.kind() {
             TokenKind::Name
@@ -937,18 +1036,18 @@ pub(crate) fn find_goto_target(
         return None;
     }
 
-    let covering_node = covering_node(parsed.syntax().into(), token.range())
+    let covering_node = covering_node(syntax, token.range())
         .find_first(|node| {
             node.is_identifier() || node.is_expression() || node.is_stmt_import_from()
         })
         .ok()?;
 
-    GotoTarget::from_covering_node(&covering_node, offset, parsed.tokens())
+    GotoTarget::from_covering_node(model, &covering_node, offset, tokens)
 }
 
 /// Helper function to resolve a module name and create a navigation target.
 fn definitions_for_module<'db>(
-    model: &SemanticModel,
+    model: &SemanticModel<'db>,
     module: Option<&str>,
     level: u32,
 ) -> Option<DefinitionsOrTargets<'db>> {

crates/ty_ide/src/goto_declaration.rs

@@ -16,9 +16,9 @@ pub fn goto_declaration(
     offset: TextSize,
 ) -> Option<RangedValue<NavigationTargets>> {
     let module = parsed_module(db, file).load(db);
-    let goto_target = find_goto_target(&module, offset)?;
-
     let model = SemanticModel::new(db, file);
+    let goto_target = find_goto_target(&model, &module, offset)?;
+
     let declaration_targets = goto_target
         .get_definition_targets(&model, ImportAliasResolution::ResolveAliases)?
         .declaration_targets(db)?;
@@ -889,6 +889,190 @@ def another_helper(path):
         ");
     }
 
+    #[test]
+    fn goto_declaration_string_annotation1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCla<CURSOR>ss" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> main.py:4:7
+          |
+        2 | a: "MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        info: Source
+         --> main.py:2:5
+          |
+        2 | a: "MyClass" = 1
+          |     ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_declaration_string_annotation2() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyCl<CURSOR>ass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> main.py:4:7
+          |
+        2 | a: "None | MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        info: Source
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_declaration_string_annotation3() {
+        let test = cursor_test(
+            r#"
+        a: "None |<CURSOR> MyClass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_declaration_string_annotation4() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass<CURSOR>" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> main.py:4:7
+          |
+        2 | a: "None | MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        info: Source
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_declaration_string_annotation5() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass"<CURSOR> = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_declaration_string_annotation_dangling1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass |" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_declaration_string_annotation_dangling2() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass | No" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> main.py:4:7
+          |
+        2 | a: "MyClass | No" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        info: Source
+         --> main.py:2:5
+          |
+        2 | a: "MyClass | No" = 1
+          |     ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_declaration_string_annotation_dangling3() {
+        let test = cursor_test(
+            r#"
+        a: "MyClass | N<CURSOR>o" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_declaration(), @"No goto target found");
+    }
+
     #[test]
     fn goto_declaration_nested_instance_attribute() {
         let test = cursor_test(
@@ -1070,6 +1254,45 @@ def outer():
         "#);
     }
 
+    #[test]
+    fn goto_declaration_nonlocal_stmt() {
+        let test = cursor_test(
+            r#"
+def outer():
+    xy = "outer_value"
+    
+    def inner():
+        nonlocal x<CURSOR>y
+        xy = "modified"
+        return x  # Should find the nonlocal x declaration in outer scope
+    
+    return inner
+"#,
+        );
+
+        // Should find the variable declaration in the outer scope, not the nonlocal statement
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> main.py:3:5
+          |
+        2 | def outer():
+        3 |     xy = "outer_value"
+          |     ^^
+        4 |
+        5 |     def inner():
+          |
+        info: Source
+         --> main.py:6:18
+          |
+        5 |     def inner():
+        6 |         nonlocal xy
+          |                  ^^
+        7 |         xy = "modified"
+        8 |         return x  # Should find the nonlocal x declaration in outer scope
+          |
+        "#);
+    }
+
     #[test]
     fn goto_declaration_global_binding() {
         let test = cursor_test(
@@ -1104,6 +1327,41 @@ def function():
         "#);
     }
 
+    #[test]
+    fn goto_declaration_global_stmt() {
+        let test = cursor_test(
+            r#"
+global_var = "global_value"
+
+def function():
+    global global_<CURSOR>var
+    global_var = "modified"
+    return global_var  # Should find the global variable declaration
+"#,
+        );
+
+        // Should find the global variable declaration, not the global statement
+        assert_snapshot!(test.goto_declaration(), @r#"
+        info[goto-declaration]: Declaration
+         --> main.py:2:1
+          |
+        2 | global_var = "global_value"
+          | ^^^^^^^^^^
+        3 |
+        4 | def function():
+          |
+        info: Source
+         --> main.py:5:12
+          |
+        4 | def function():
+        5 |     global global_var
+          |            ^^^^^^^^^^
+        6 |     global_var = "modified"
+        7 |     return global_var  # Should find the global variable declaration
+          |
+        "#);
+    }
+
     #[test]
     fn goto_declaration_inherited_attribute() {
         let test = cursor_test(

crates/ty_ide/src/goto_definition.rs

@@ -17,8 +17,8 @@ pub fn goto_definition(
     offset: TextSize,
 ) -> Option<RangedValue<NavigationTargets>> {
     let module = parsed_module(db, file).load(db);
-    let goto_target = find_goto_target(&module, offset)?;
     let model = SemanticModel::new(db, file);
+    let goto_target = find_goto_target(&model, &module, offset)?;
     let definition_targets = goto_target
         .get_definition_targets(&model, ImportAliasResolution::ResolveAliases)?
         .definition_targets(db)?;

crates/ty_ide/src/goto_references.rs

@@ -3,6 +3,7 @@ use crate::references::{ReferencesMode, references};
 use crate::{Db, ReferenceTarget};
 use ruff_db::files::File;
 use ruff_text_size::TextSize;
+use ty_python_semantic::SemanticModel;
 
 /// Find all references to a symbol at the given position.
 /// Search for references across all files in the project.
@@ -14,9 +15,10 @@ pub fn goto_references(
 ) -> Option<Vec<ReferenceTarget>> {
     let parsed = ruff_db::parsed::parsed_module(db, file);
     let module = parsed.load(db);
+    let model = SemanticModel::new(db, file);
 
     // Get the definitions for the symbol at the cursor position
-    let goto_target = find_goto_target(&module, offset)?;
+    let goto_target = find_goto_target(&model, &module, offset)?;
 
     let mode = if include_declaration {
         ReferencesMode::References
@@ -147,7 +149,6 @@ result = calculate_sum(value=42)
     }
 
     #[test]
-    #[ignore] // TODO: Enable when nonlocal support is fully implemented in goto.rs
     fn test_nonlocal_variable_references() {
         let test = cursor_test(
             "
@@ -181,7 +182,7 @@ def outer_function():
         2 | def outer_function():
         3 |     counter = 0
           |     ^^^^^^^
-        4 |     
+        4 |
         5 |     def increment():
           |
 
@@ -212,7 +213,7 @@ def outer_function():
          7 |         counter += 1
          8 |         return counter
            |                ^^^^^^^
-         9 |     
+         9 |
         10 |     def decrement():
            |
 
@@ -243,7 +244,7 @@ def outer_function():
         12 |         counter -= 1
         13 |         return counter
            |                ^^^^^^^
-        14 |     
+        14 |
         15 |     # Use counter in outer scope
            |
 
@@ -264,14 +265,13 @@ def outer_function():
         18 |     decrement()
         19 |     final = counter
            |             ^^^^^^^
-        20 |     
+        20 |
         21 |     return increment, decrement
            |
         ");
     }
 
     #[test]
-    #[ignore] // TODO: Enable when global support is fully implemented in goto.rs
     fn test_global_variable_references() {
         let test = cursor_test(
             "
@@ -710,6 +710,194 @@ cls = MyClass
         ");
     }
 
+    #[test]
+    fn references_string_annotation1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCla<CURSOR>ss" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @r#"
+        info[references]: Reference 1
+         --> main.py:2:5
+          |
+        2 | a: "MyClass" = 1
+          |     ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+
+        info[references]: Reference 2
+         --> main.py:4:7
+          |
+        2 | a: "MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn references_string_annotation2() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyCl<CURSOR>ass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @r#"
+        info[references]: Reference 1
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+
+        info[references]: Reference 2
+         --> main.py:4:7
+          |
+        2 | a: "None | MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn references_string_annotation3() {
+        let test = cursor_test(
+            r#"
+        a: "None |<CURSOR> MyClass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
+    #[test]
+    fn references_string_annotation4() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass<CURSOR>" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @r#"
+        info[references]: Reference 1
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+
+        info[references]: Reference 2
+         --> main.py:4:7
+          |
+        2 | a: "None | MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn references_string_annotation5() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass"<CURSOR> = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
+    #[test]
+    fn references_string_annotation_dangling1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass |" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
+    #[test]
+    fn references_string_annotation_dangling2() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass | No" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @r#"
+        info[references]: Reference 1
+         --> main.py:2:5
+          |
+        2 | a: "MyClass | No" = 1
+          |     ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+
+        info[references]: Reference 2
+         --> main.py:4:7
+          |
+        2 | a: "MyClass | No" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn references_string_annotation_dangling3() {
+        let test = cursor_test(
+            r#"
+        a: "MyClass | N<CURSOR>o" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.references(), @"No references found");
+    }
+
     #[test]
     fn test_multi_file_function_references() {
         let test = CursorTest::builder()

crates/ty_ide/src/goto_type_definition.rs

@@ -11,9 +11,9 @@ pub fn goto_type_definition(
     offset: TextSize,
 ) -> Option<RangedValue<NavigationTargets>> {
     let module = parsed_module(db, file).load(db);
-    let goto_target = find_goto_target(&module, offset)?;
-
     let model = SemanticModel::new(db, file);
+    let goto_target = find_goto_target(&model, &module, offset)?;
+
     let ty = goto_target.inferred_type(&model)?;
 
     tracing::debug!("Inferred type of covering node is {}", ty.display(db));
@@ -744,6 +744,226 @@ mod tests {
         assert_snapshot!(test.goto_type_definition(), @"No type definitions found");
     }
 
+    #[test]
+    fn goto_type_string_annotation1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCla<CURSOR>ss" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+         --> main.py:4:7
+          |
+        2 | a: "MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        info: Source
+         --> main.py:2:5
+          |
+        2 | a: "MyClass" = 1
+          |     ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_type_string_annotation2() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyCl<CURSOR>ass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_type_string_annotation3() {
+        let test = cursor_test(
+            r#"
+        a: "None |<CURSOR> MyClass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+         --> main.py:4:7
+          |
+        2 | a: "None | MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        info: Source
+         --> main.py:2:4
+          |
+        2 | a: "None | MyClass" = 1
+          |    ^^^^^^^^^^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+
+        info[goto-type-definition]: Type definition
+           --> stdlib/types.pyi:950:11
+            |
+        948 | if sys.version_info >= (3, 10):
+        949 |     @final
+        950 |     class NoneType:
+            |           ^^^^^^^^
+        951 |         """The type of the None singleton."""
+            |
+        info: Source
+         --> main.py:2:4
+          |
+        2 | a: "None | MyClass" = 1
+          |    ^^^^^^^^^^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_type_string_annotation4() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass<CURSOR>" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_type_string_annotation5() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass"<CURSOR> = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+         --> main.py:4:7
+          |
+        2 | a: "None | MyClass" = 1
+        3 |
+        4 | class MyClass:
+          |       ^^^^^^^
+        5 |     """some docs"""
+          |
+        info: Source
+         --> main.py:2:4
+          |
+        2 | a: "None | MyClass" = 1
+          |    ^^^^^^^^^^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+
+        info[goto-type-definition]: Type definition
+           --> stdlib/types.pyi:950:11
+            |
+        948 | if sys.version_info >= (3, 10):
+        949 |     @final
+        950 |     class NoneType:
+            |           ^^^^^^^^
+        951 |         """The type of the None singleton."""
+            |
+        info: Source
+         --> main.py:2:4
+          |
+        2 | a: "None | MyClass" = 1
+          |    ^^^^^^^^^^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_type_string_annotation_dangling1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass |" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+          --> stdlib/ty_extensions.pyi:20:1
+           |
+        19 | # Types
+        20 | Unknown = object()
+           | ^^^^^^^
+        21 | AlwaysTruthy = object()
+        22 | AlwaysFalsy = object()
+           |
+        info: Source
+         --> main.py:2:4
+          |
+        2 | a: "MyClass |" = 1
+          |    ^^^^^^^^^^^
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_type_string_annotation_dangling2() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass | No" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_type_string_annotation_dangling3() {
+        let test = cursor_test(
+            r#"
+        a: "MyClass | N<CURSOR>o" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.goto_type_definition(), @"No goto target found");
+    }
+
     #[test]
     fn goto_type_on_keyword_argument() {
         let test = cursor_test(
@@ -842,6 +1062,118 @@ f(**kwargs<CURSOR>)
         "#);
     }
 
+    #[test]
+    fn goto_type_nonlocal_binding() {
+        let test = cursor_test(
+            r#"
+def outer():
+    x = "outer_value"
+    
+    def inner():
+        nonlocal x
+        x = "modified"
+        return x<CURSOR>  # Should find the nonlocal x declaration in outer scope
+    
+    return inner
+"#,
+        );
+
+        // Should find the variable declaration in the outer scope, not the nonlocal statement
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+           --> stdlib/builtins.pyi:915:7
+            |
+        914 | @disjoint_base
+        915 | class str(Sequence[str]):
+            |       ^^^
+        916 |     """str(object='') -> str
+        917 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+            |
+        info: Source
+          --> main.py:8:16
+           |
+         6 |         nonlocal x
+         7 |         x = "modified"
+         8 |         return x  # Should find the nonlocal x declaration in outer scope
+           |                ^
+         9 |
+        10 |     return inner
+           |
+        "#);
+    }
+
+    #[test]
+    fn goto_type_nonlocal_stmt() {
+        let test = cursor_test(
+            r#"
+def outer():
+    xy = "outer_value"
+    
+    def inner():
+        nonlocal x<CURSOR>y
+        xy = "modified"
+        return x  # Should find the nonlocal x declaration in outer scope
+    
+    return inner
+"#,
+        );
+
+        // Should find the variable declaration in the outer scope, not the nonlocal statement
+        assert_snapshot!(test.goto_type_definition(), @"No goto target found");
+    }
+
+    #[test]
+    fn goto_type_global_binding() {
+        let test = cursor_test(
+            r#"
+global_var = "global_value"
+
+def function():
+    global global_var
+    global_var = "modified"
+    return global_<CURSOR>var  # Should find the global variable declaration
+"#,
+        );
+
+        // Should find the global variable declaration, not the global statement
+        assert_snapshot!(test.goto_type_definition(), @r#"
+        info[goto-type-definition]: Type definition
+           --> stdlib/builtins.pyi:915:7
+            |
+        914 | @disjoint_base
+        915 | class str(Sequence[str]):
+            |       ^^^
+        916 |     """str(object='') -> str
+        917 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+            |
+        info: Source
+         --> main.py:7:12
+          |
+        5 |     global global_var
+        6 |     global_var = "modified"
+        7 |     return global_var  # Should find the global variable declaration
+          |            ^^^^^^^^^^
+          |
+        "#);
+    }
+
+    #[test]
+    fn goto_type_global_stmt() {
+        let test = cursor_test(
+            r#"
+global_var = "global_value"
+
+def function():
+    global global_<CURSOR>var
+    global_var = "modified"
+    return global_var  # Should find the global variable declaration
+"#,
+        );
+
+        // Should find the global variable declaration, not the global statement
+        assert_snapshot!(test.goto_type_definition(), @"No goto target found");
+    }
+
     #[test]
     fn goto_type_of_expression_with_builtin() {
         let test = cursor_test(

crates/ty_ide/src/hover.rs

@@ -11,7 +11,8 @@ use ty_python_semantic::{DisplaySettings, SemanticModel};
 
 pub fn hover(db: &dyn Db, file: File, offset: TextSize) -> Option<RangedValue<Hover<'_>>> {
     let parsed = parsed_module(db, file).load(db);
-    let goto_target = find_goto_target(&parsed, offset)?;
+    let model = SemanticModel::new(db, file);
+    let goto_target = find_goto_target(&model, &parsed, offset)?;
 
     if let GotoTarget::Expression(expr) = goto_target {
         if expr.is_literal_expr() {
@@ -19,7 +20,6 @@ pub fn hover(db: &dyn Db, file: File, offset: TextSize) -> Option<RangedValue<Ho
         }
     }
 
-    let model = SemanticModel::new(db, file);
     let docs = goto_target
         .get_definition_targets(
             &model,
@@ -904,6 +904,191 @@ mod tests {
         ");
     }
 
+    #[test]
+    fn hover_string_annotation1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCla<CURSOR>ss" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @r#"
+        MyClass
+        ---------------------------------------------
+        some docs
+
+        ---------------------------------------------
+        ```python
+        MyClass
+        ```
+        ---
+        some docs
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> main.py:2:5
+          |
+        2 | a: "MyClass" = 1
+          |     ^^^^^-^
+          |     |    |
+          |     |    Cursor offset
+          |     source
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn hover_string_annotation2() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyCl<CURSOR>ass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @r#"
+        some docs
+
+        ---------------------------------------------
+        some docs
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^-^^
+          |            |   |
+          |            |   Cursor offset
+          |            source
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn hover_string_annotation3() {
+        let test = cursor_test(
+            r#"
+        a: "None |<CURSOR> MyClass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @"Hover provided no content");
+    }
+
+    #[test]
+    fn hover_string_annotation4() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass<CURSOR>" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @r#"
+        some docs
+
+        ---------------------------------------------
+        some docs
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^^^^- Cursor offset
+          |            |
+          |            source
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn hover_string_annotation5() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass"<CURSOR> = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @"Hover provided no content");
+    }
+
+    #[test]
+    fn hover_string_annotation_dangling1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass |" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @"Hover provided no content");
+    }
+
+    #[test]
+    fn hover_string_annotation_dangling2() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass | No" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @r#"
+        some docs
+
+        ---------------------------------------------
+        some docs
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> main.py:2:5
+          |
+        2 | a: "MyClass | No" = 1
+          |     ^^^^-^^
+          |     |   |
+          |     |   Cursor offset
+          |     source
+        3 |
+        4 | class MyClass:
+          |
+        "#);
+    }
+
+    #[test]
+    fn hover_string_annotation_dangling3() {
+        let test = cursor_test(
+            r#"
+        a: "MyClass | N<CURSOR>o" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.hover(), @"Hover provided no content");
+    }
+
     #[test]
     fn hover_overload_type_disambiguated1() {
         let test = CursorTest::builder()
@@ -1463,6 +1648,117 @@ def ab(a: int, *, c: int):
         ");
     }
 
+    #[test]
+    fn hover_nonlocal_binding() {
+        let test = cursor_test(
+            r#"
+def outer():
+    x = "outer_value"
+    
+    def inner():
+        nonlocal x
+        x = "modified"
+        return x<CURSOR>  # Should find the nonlocal x declaration in outer scope
+    
+    return inner
+"#,
+        );
+
+        // Should find the variable declaration in the outer scope, not the nonlocal statement
+        assert_snapshot!(test.hover(), @r#"
+        Literal["modified"]
+        ---------------------------------------------
+        ```python
+        Literal["modified"]
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+          --> main.py:8:16
+           |
+         6 |         nonlocal x
+         7 |         x = "modified"
+         8 |         return x  # Should find the nonlocal x declaration in outer scope
+           |                ^- Cursor offset
+           |                |
+           |                source
+         9 |
+        10 |     return inner
+           |
+        "#);
+    }
+
+    #[test]
+    fn hover_nonlocal_stmt() {
+        let test = cursor_test(
+            r#"
+def outer():
+    xy = "outer_value"
+    
+    def inner():
+        nonlocal x<CURSOR>y
+        xy = "modified"
+        return x  # Should find the nonlocal x declaration in outer scope
+    
+    return inner
+"#,
+        );
+
+        // Should find the variable declaration in the outer scope, not the nonlocal statement
+        assert_snapshot!(test.hover(), @"Hover provided no content");
+    }
+
+    #[test]
+    fn hover_global_binding() {
+        let test = cursor_test(
+            r#"
+global_var = "global_value"
+
+def function():
+    global global_var
+    global_var = "modified"
+    return global_<CURSOR>var  # Should find the global variable declaration
+"#,
+        );
+
+        // Should find the global variable declaration, not the global statement
+        assert_snapshot!(test.hover(), @r#"
+        Literal["modified"]
+        ---------------------------------------------
+        ```python
+        Literal["modified"]
+        ```
+        ---------------------------------------------
+        info[hover]: Hovered content is
+         --> main.py:7:12
+          |
+        5 |     global global_var
+        6 |     global_var = "modified"
+        7 |     return global_var  # Should find the global variable declaration
+          |            ^^^^^^^-^^
+          |            |      |
+          |            |      Cursor offset
+          |            source
+          |
+        "#);
+    }
+
+    #[test]
+    fn hover_global_stmt() {
+        let test = cursor_test(
+            r#"
+global_var = "global_value"
+
+def function():
+    global global_<CURSOR>var
+    global_var = "modified"
+    return global_var  # Should find the global variable declaration
+"#,
+        );
+
+        // Should find the global variable declaration, not the global statement
+        assert_snapshot!(test.hover(), @"Hover provided no content");
+    }
+
     #[test]
     fn hover_module_import() {
         let mut test = cursor_test(

crates/ty_ide/src/inlay_hints.rs

@@ -6,8 +6,8 @@ use ruff_db::parsed::parsed_module;
 use ruff_python_ast::visitor::source_order::{self, SourceOrderVisitor, TraversalSignal};
 use ruff_python_ast::{AnyNodeRef, ArgOrKeyword, Expr, ExprUnaryOp, Stmt, UnaryOp};
 use ruff_text_size::{Ranged, TextRange, TextSize};
-use ty_python_semantic::types::Type;
 use ty_python_semantic::types::ide_support::inlay_hint_call_argument_details;
+use ty_python_semantic::types::{Type, TypeDetail};
 use ty_python_semantic::{HasType, SemanticModel};
 
 #[derive(Debug, Clone)]
@@ -15,10 +15,12 @@ pub struct InlayHint {
     pub position: TextSize,
     pub kind: InlayHintKind,
     pub label: InlayHintLabel,
+    pub text_edits: Vec<InlayHintTextEdit>,
 }
 
 impl InlayHint {
-    fn variable_type(position: TextSize, ty: Type, db: &dyn Db) -> Self {
+    fn variable_type(expr: &Expr, ty: Type, db: &dyn Db, allow_edits: bool) -> Self {
+        let position = expr.range().end();
         // Render the type to a string, and get subspans for all the types that make it up
         let details = ty.display(db).to_string_parts();
 
@@ -34,7 +36,7 @@ impl InlayHint {
         let mut label_parts = vec![": ".into()];
         for (target, detail) in details.targets.iter().zip(&details.details) {
             match detail {
-                ty_python_semantic::types::TypeDetail::Type(ty) => {
+                TypeDetail::Type(ty) => {
                     let start = target.start().to_usize();
                     let end = target.end().to_usize();
                     // If we skipped over some bytes, push them with no target
@@ -50,9 +52,9 @@ impl InlayHint {
                         offset = end;
                     }
                 }
-                ty_python_semantic::types::TypeDetail::SignatureStart
-                | ty_python_semantic::types::TypeDetail::SignatureEnd
-                | ty_python_semantic::types::TypeDetail::Parameter(_) => {
+                TypeDetail::SignatureStart
+                | TypeDetail::SignatureEnd
+                | TypeDetail::Parameter(_) => {
                     // Don't care about these
                 }
             }
@@ -62,10 +64,20 @@ impl InlayHint {
             label_parts.push(details.label[offset..details.label.len()].into());
         }
 
+        let text_edits = if details.is_valid_syntax && allow_edits {
+            vec![InlayHintTextEdit {
+                range: TextRange::new(position, position),
+                new_text: format!(": {}", details.label),
+            }]
+        } else {
+            vec![]
+        };
+
         Self {
             position,
             kind: InlayHintKind::Type,
             label: InlayHintLabel { parts: label_parts },
+            text_edits,
         }
     }
 
@@ -83,6 +95,7 @@ impl InlayHint {
             position,
             kind: InlayHintKind::CallArgumentName,
             label: InlayHintLabel { parts: label_parts },
+            text_edits: vec![],
         }
     }
 
@@ -175,6 +188,12 @@ impl From<&str> for InlayHintLabelPart {
     }
 }
 
+#[derive(Debug, Clone)]
+pub struct InlayHintTextEdit {
+    pub range: TextRange,
+    pub new_text: String,
+}
+
 pub fn inlay_hints(
     db: &dyn Db,
     file: File,
@@ -234,6 +253,7 @@ struct InlayHintVisitor<'a, 'db> {
     in_assignment: bool,
     range: TextRange,
     settings: &'a InlayHintSettings,
+    in_no_edits_allowed: bool,
 }
 
 impl<'a, 'db> InlayHintVisitor<'a, 'db> {
@@ -245,15 +265,16 @@ impl<'a, 'db> InlayHintVisitor<'a, 'db> {
             in_assignment: false,
             range,
             settings,
+            in_no_edits_allowed: false,
         }
     }
 
-    fn add_type_hint(&mut self, position: TextSize, ty: Type<'db>) {
+    fn add_type_hint(&mut self, expr: &Expr, ty: Type<'db>, allow_edits: bool) {
         if !self.settings.variable_types {
             return;
         }
 
-        let inlay_hint = InlayHint::variable_type(position, ty, self.db);
+        let inlay_hint = InlayHint::variable_type(expr, ty, self.db, allow_edits);
 
         self.hints.push(inlay_hint);
     }
@@ -297,9 +318,13 @@ impl SourceOrderVisitor<'_> for InlayHintVisitor<'_, '_> {
         match stmt {
             Stmt::Assign(assign) => {
                 self.in_assignment = !type_hint_is_excessive_for_expr(&assign.value);
+                if !annotations_are_valid_syntax(assign) {
+                    self.in_no_edits_allowed = true;
+                }
                 for target in &assign.targets {
                     self.visit_expr(target);
                 }
+                self.in_no_edits_allowed = false;
                 self.in_assignment = false;
 
                 self.visit_expr(&assign.value);
@@ -325,7 +350,7 @@ impl SourceOrderVisitor<'_> for InlayHintVisitor<'_, '_> {
                 if self.in_assignment {
                     if name.ctx.is_store() {
                         let ty = expr.inferred_type(&self.model);
-                        self.add_type_hint(expr.range().end(), ty);
+                        self.add_type_hint(expr, ty, !self.in_no_edits_allowed);
                     }
                 }
                 source_order::walk_expr(self, expr);
@@ -334,7 +359,7 @@ impl SourceOrderVisitor<'_> for InlayHintVisitor<'_, '_> {
                 if self.in_assignment {
                     if attribute.ctx.is_store() {
                         let ty = expr.inferred_type(&self.model);
-                        self.add_type_hint(expr.range().end(), ty);
+                        self.add_type_hint(expr, ty, !self.in_no_edits_allowed);
                     }
                 }
                 source_order::walk_expr(self, expr);
@@ -420,6 +445,22 @@ fn type_hint_is_excessive_for_expr(expr: &Expr) -> bool {
     }
 }
 
+fn annotations_are_valid_syntax(stmt_assign: &ruff_python_ast::StmtAssign) -> bool {
+    if stmt_assign.targets.len() > 1 {
+        return false;
+    }
+
+    if stmt_assign
+        .targets
+        .iter()
+        .any(|target| matches!(target, Expr::Tuple(_)))
+    {
+        return false;
+    }
+
+    true
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -427,6 +468,7 @@ mod tests {
     use crate::NavigationTarget;
     use crate::tests::IntoDiagnostic;
     use insta::{assert_snapshot, internals::SettingsBindDropGuard};
+    use itertools::Itertools;
     use ruff_db::{
         diagnostic::{
             Annotation, Diagnostic, DiagnosticFormat, DiagnosticId, DisplayDiagnosticConfig,
@@ -517,12 +559,15 @@ mod tests {
         fn inlay_hints_with_settings(&mut self, settings: &InlayHintSettings) -> String {
             let hints = inlay_hints(&self.db, self.file, self.range, settings);
 
-            let mut buf = source_text(&self.db, self.file).as_str().to_string();
+            let mut inlay_hint_buf = source_text(&self.db, self.file).as_str().to_string();
+            let mut text_edit_buf = inlay_hint_buf.clone();
 
             let mut tbd_diagnostics = Vec::new();
 
             let mut offset = 0;
 
+            let mut edit_offset = 0;
+
             for hint in hints {
                 let end_position = hint.position.to_usize() + offset;
                 let mut hint_str = "[".to_string();
@@ -538,36 +583,65 @@ mod tests {
                     hint_str.push_str(part.text());
                 }
 
+                for edit in hint.text_edits {
+                    let start = edit.range.start().to_usize() + edit_offset;
+                    let end = edit.range.end().to_usize() + edit_offset;
+
+                    text_edit_buf.replace_range(start..end, &edit.new_text);
+
+                    if start == end {
+                        edit_offset += edit.new_text.len();
+                    } else {
+                        edit_offset += edit.new_text.len() - edit.range.len().to_usize();
+                    }
+                }
+
                 hint_str.push(']');
                 offset += hint_str.len();
 
-                buf.insert_str(end_position, &hint_str);
+                inlay_hint_buf.insert_str(end_position, &hint_str);
             }
 
-            self.db.write_file("main2.py", &buf).unwrap();
+            self.db.write_file("main2.py", &inlay_hint_buf).unwrap();
             let inlayed_file =
                 system_path_to_file(&self.db, "main2.py").expect("newly written file to existing");
 
-            let diagnostics = tbd_diagnostics.into_iter().map(|(label_range, target)| {
+            let location_diagnostics = tbd_diagnostics.into_iter().map(|(label_range, target)| {
                 InlayHintLocationDiagnostic::new(FileRange::new(inlayed_file, label_range), &target)
             });
 
-            let mut rendered_diagnostics = self.render_diagnostics(diagnostics);
+            let mut rendered_diagnostics = location_diagnostics
+                .map(|diagnostic| self.render_diagnostic(diagnostic))
+                .join("");
 
             if !rendered_diagnostics.is_empty() {
                 rendered_diagnostics = format!(
                     "{}{}",
                     crate::MarkupKind::PlainText.horizontal_line(),
                     rendered_diagnostics
+                        .strip_suffix("\n")
+                        .unwrap_or(&rendered_diagnostics)
                 );
             }
 
-            format!("{buf}{rendered_diagnostics}",)
+            let rendered_edit_diagnostic = if edit_offset != 0 {
+                let edit_diagnostic = InlayHintEditDiagnostic::new(text_edit_buf);
+                let text_edit_buf = self.render_diagnostic(edit_diagnostic);
+
+                format!(
+                    "{}{}",
+                    crate::MarkupKind::PlainText.horizontal_line(),
+                    text_edit_buf
+                )
+            } else {
+                String::new()
+            };
+
+            format!("{inlay_hint_buf}{rendered_diagnostics}{rendered_edit_diagnostic}",)
         }
 
-        fn render_diagnostics<I, D>(&self, diagnostics: I) -> String
+        fn render_diagnostic<D>(&self, diagnostic: D) -> String
         where
-            I: IntoIterator<Item = D>,
             D: IntoDiagnostic,
         {
             use std::fmt::Write;
@@ -578,10 +652,8 @@ mod tests {
                 .color(false)
                 .format(DiagnosticFormat::Full);
 
-            for diagnostic in diagnostics {
-                let diag = diagnostic.into_diagnostic();
-                write!(buf, "{}", diag.display(&self.db, &config)).unwrap();
-            }
+            let diag = diagnostic.into_diagnostic();
+            write!(buf, "{}", diag.display(&self.db, &config)).unwrap();
 
             buf
         }
@@ -728,6 +800,20 @@ mod tests {
         10 | bb[: Literal[b"foo"]] = aa
            |              ^^^^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+
+        x = 1
+        y: Literal[1] = x
+        z: int = i(1)
+        w: int = z
+        aa = b'foo'
+        bb: Literal[b"foo"] = aa
         "#);
     }
 
@@ -1321,6 +1407,20 @@ mod tests {
         10 | w[: tuple[int, str]] = z
            |                ^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+        def s(x: str, /) -> str:
+            return x
+
+        x = (1, 'abc')
+        y: tuple[Literal[1], Literal["abc"]] = x
+        z: tuple[int, str] = (i(1), s('abc'))
+        w: tuple[int, str] = z
         "#);
     }
 
@@ -1654,6 +1754,18 @@ mod tests {
         8 | w[: int] = z
           |     ^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+
+        x: int = 1
+        y: Literal[1] = x
+        z: int = i(1)
+        w: int = z
         "#);
     }
 
@@ -1691,6 +1803,15 @@ mod tests {
           |     ^^^
         5 | z = x
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def i(x: int, /) -> int:
+            return x
+        x: int = i(1)
+        z = x
         "#);
     }
 
@@ -1810,6 +1931,18 @@ mod tests {
         8 | a.y[: int] = int(3)
           |       ^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class A:
+            def __init__(self, y):
+                self.x: int = int(1)
+                self.y: Unknown = y
+
+        a: A = A(2)
+        a.y: int = int(3)
         "#);
     }
 
@@ -2640,6 +2773,22 @@ mod tests {
         12 | k[: list[Unknown | int | float]] = [-1, -2.0]
            |                          ^^^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        a: list[Unknown | int] = [1, 2]
+        b: list[Unknown | float] = [1.0, 2.0]
+        c: list[Unknown | bool] = [True, False]
+        d: list[Unknown | None] = [None, None]
+        e: list[Unknown | str] = ["hel", "lo"]
+        f: list[Unknown | str] = ['the', 're']
+        g: list[Unknown | str] = [f"{ft}", f"{ft}"]
+        h: list[Unknown | Template] = [t"wow %d", t"wow %d"]
+        i: list[Unknown | bytes] = [b'/x01', b'/x02']
+        j: list[Unknown | int | float] = [+1, +2.0]
+        k: list[Unknown | int | float] = [-1, -2.0]
         "#);
     }
 
@@ -2811,6 +2960,19 @@ mod tests {
         9 | c[: MyClass], d[: MyClass] = (MyClass(), MyClass())
           |                   ^^^^^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class MyClass:
+            def __init__(self):
+                self.x: int = 1
+
+        x: MyClass = MyClass()
+        y: tuple[MyClass, MyClass] = (MyClass(), MyClass())
+        a, b = MyClass(), MyClass()
+        c, d = (MyClass(), MyClass())
         "#);
     }
 
@@ -3681,6 +3843,20 @@ mod tests {
         10 | c[: MyClass[Unknown | int, str]], d[: MyClass[Unknown | int, str]] = (MyClass([x=][42], [y=]("a", "b")), MyClass([x=][42], [y=]("a", "…
            |                                                                                                                             ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class MyClass[T, U]:
+            def __init__(self, x: list[T], y: tuple[U, U]):
+                self.x = x
+                self.y = y
+
+        x: MyClass[Unknown | int, str] = MyClass([42], ("a", "b"))
+        y: tuple[MyClass[Unknown | int, str], MyClass[Unknown | int, str]] = (MyClass([42], ("a", "b")), MyClass([42], ("a", "b")))
+        a, b = MyClass([42], ("a", "b")), MyClass([42], ("a", "b"))
+        c, d = (MyClass([42], ("a", "b")), MyClass([42], ("a", "b")))
         "#);
     }
 
@@ -3836,6 +4012,20 @@ mod tests {
         10 | foo([x=]val.y)
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+                self.x: int = 1
+                self.y: int = 2
+        val: MyClass = MyClass()
+
+        foo(val.x)
+        foo(val.y)
         ");
     }
 
@@ -3901,6 +4091,20 @@ mod tests {
         10 | foo([x=]x.y)
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+                self.x: int = 1
+                self.y: int = 2
+        x: MyClass = MyClass()
+
+        foo(x.x)
+        foo(x.y)
         ");
     }
 
@@ -3969,6 +4173,22 @@ mod tests {
         12 | foo([x=]val.y())
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+            def x() -> int:
+                return 1
+            def y() -> int:
+                return 2
+        val: MyClass = MyClass()
+
+        foo(val.x())
+        foo(val.y())
         ");
     }
 
@@ -4043,6 +4263,24 @@ mod tests {
         14 | foo([x=]val.y()[1])
            |      ^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        from typing import List
+
+        def foo(x: int): pass
+        class MyClass:
+            def __init__(self):
+            def x() -> List[int]:
+                return 1
+            def y() -> List[int]:
+                return 2
+        val: MyClass = MyClass()
+
+        foo(val.x()[0])
+        foo(val.y()[1])
         ");
     }
 
@@ -4193,6 +4431,17 @@ mod tests {
         7 | foo([x=]y[0])
           |      ^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def foo(x: int): pass
+        x: list[Unknown | int] = [1]
+        y: list[Unknown | int] = [2]
+
+        foo(x[0])
+        foo(y[0])
         "#);
     }
 
@@ -4378,6 +4627,15 @@ mod tests {
         5 | f[: Foo] = Foo([x=]1)
           |                 ^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class Foo:
+            def __init__(self, x: int): pass
+        Foo(1)
+        f: Foo = Foo(1)
         ");
     }
 
@@ -4450,6 +4708,15 @@ mod tests {
         5 | f[: Foo] = Foo([x=]1)
           |                 ^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class Foo:
+            def __new__(cls, x: int): pass
+        Foo(1)
+        f: Foo = Foo(1)
         ");
     }
 
@@ -5197,6 +5464,15 @@ mod tests {
           |         ^^^^^^^^^^^^^
         5 | my_func(x="hello")
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        from typing import LiteralString
+        def my_func(x: LiteralString):
+            y: LiteralString = x
+        my_func(x="hello")
         "#);
     }
 
@@ -5339,6 +5615,23 @@ mod tests {
         13 |     y[: Literal[1, 2, 3, "hello"] | None] = x
            |                                     ^^^^
            |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def branch(cond: int):
+            if cond < 10:
+                x = 1
+            elif cond < 20:
+                x = 2
+            elif cond < 30:
+                x = 3
+            elif cond < 40:
+                x = "hello"
+            else:
+                x = None
+            y: Literal[1, 2, 3, "hello"] | None = x
         "#);
     }
 
@@ -5454,6 +5747,13 @@ mod tests {
         3 |     y[: type[list[str]]] = type(x)
           |                   ^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        def f(x: list[str]):
+            y: type[list[str]] = type(x)
         "#);
     }
 
@@ -5493,6 +5793,16 @@ mod tests {
         6 | ab[: property] = F.whatever
           |      ^^^^^^^^
           |
+
+        ---------------------------------------------
+        info[inlay-hint-edit]: File after edits
+        info: Source
+
+        class F:
+            @property
+            def whatever(self): ...
+
+        ab: property = F.whatever
         ");
     }
 
@@ -5810,6 +6120,196 @@ mod tests {
         ");
     }
 
+    #[test]
+    fn test_function_signature_inlay_hint() {
+        let mut test = inlay_hint_test(
+            "
+                  def foo(x: int, *y: bool, z: str | int | list[str]): ...
+
+                  a = foo",
+        );
+
+        assert_snapshot!(test.inlay_hints(), @r#"
+        def foo(x: int, *y: bool, z: str | int | list[str]): ...
+
+        a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+        ---------------------------------------------
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:348:7
+            |
+        347 | @disjoint_base
+        348 | class int:
+            |       ^^^
+        349 |     """int([x]) -> integer
+        350 |     int(x, base=10) -> integer
+            |
+        info: Source
+         --> main2.py:4:16
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+            --> stdlib/builtins.pyi:2591:7
+             |
+        2590 | @final
+        2591 | class bool(int):
+             |       ^^^^
+        2592 |     """Returns True when the argument is true, False otherwise.
+        2593 |     The builtins True and False are the only two instances of the class bool.
+             |
+        info: Source
+         --> main2.py:4:25
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                         ^^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:915:7
+            |
+        914 | @disjoint_base
+        915 | class str(Sequence[str]):
+            |       ^^^
+        916 |     """str(object='') -> str
+        917 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+            |
+        info: Source
+         --> main2.py:4:37
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                     ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:348:7
+            |
+        347 | @disjoint_base
+        348 | class int:
+            |       ^^^
+        349 |     """int([x]) -> integer
+        350 |     int(x, base=10) -> integer
+            |
+        info: Source
+         --> main2.py:4:43
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                           ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+            --> stdlib/builtins.pyi:2802:7
+             |
+        2801 | @disjoint_base
+        2802 | class list(MutableSequence[_T]):
+             |       ^^^^
+        2803 |     """Built-in mutable sequence.
+             |
+        info: Source
+         --> main2.py:4:49
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                                 ^^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+           --> stdlib/builtins.pyi:915:7
+            |
+        914 | @disjoint_base
+        915 | class str(Sequence[str]):
+            |       ^^^
+        916 |     """str(object='') -> str
+        917 |     str(bytes_or_buffer[, encoding[, errors]]) -> str
+            |
+        info: Source
+         --> main2.py:4:54
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                                      ^^^
+          |
+
+        info[inlay-hint-location]: Inlay Hint Target
+          --> stdlib/ty_extensions.pyi:20:1
+           |
+        19 | # Types
+        20 | Unknown = object()
+           | ^^^^^^^
+        21 | AlwaysTruthy = object()
+        22 | AlwaysFalsy = object()
+           |
+        info: Source
+         --> main2.py:4:63
+          |
+        2 | def foo(x: int, *y: bool, z: str | int | list[str]): ...
+        3 |
+        4 | a[: def foo(x: int, *y: bool, *, z: str | int | list[str]) -> Unknown] = foo
+          |                                                               ^^^^^^^
+          |
+        "#);
+    }
+
+    #[test]
+    fn test_module_inlay_hint() {
+        let mut test = inlay_hint_test(
+            "
+                      import foo
+
+                      a = foo",
+        );
+
+        test.with_extra_file("foo.py", "'''Foo module'''");
+
+        assert_snapshot!(test.inlay_hints(), @r"
+        import foo
+
+        a[: <module 'foo'>] = foo
+        ---------------------------------------------
+        info[inlay-hint-location]: Inlay Hint Target
+         --> foo.py:1:1
+          |
+        1 | '''Foo module'''
+          | ^^^^^^^^^^^^^^^^
+          |
+        info: Source
+         --> main2.py:4:5
+          |
+        2 | import foo
+        3 |
+        4 | a[: <module 'foo'>] = foo
+          |     ^^^^^^^^^^^^^^
+          |
+        ");
+    }
+
+    #[test]
+    fn test_literal_type_alias_inlay_hint() {
+        let mut test = inlay_hint_test(
+            "
+                        from typing import Literal
+
+                        a = Literal['a', 'b', 'c']",
+        );
+
+        assert_snapshot!(test.inlay_hints(), @r"
+        from typing import Literal
+
+        a[: <typing.Literal special form>] = Literal['a', 'b', 'c']
+        ");
+    }
+
     struct InlayHintLocationDiagnostic {
         source: FileRange,
         target: FileRange,
@@ -5847,4 +6347,31 @@ mod tests {
             main
         }
     }
+
+    struct InlayHintEditDiagnostic {
+        file_content: String,
+    }
+
+    impl InlayHintEditDiagnostic {
+        fn new(file_content: String) -> Self {
+            Self { file_content }
+        }
+    }
+
+    impl IntoDiagnostic for InlayHintEditDiagnostic {
+        fn into_diagnostic(self) -> Diagnostic {
+            let mut main = Diagnostic::new(
+                DiagnosticId::Lint(LintName::of("inlay-hint-edit")),
+                Severity::Info,
+                "File after edits".to_string(),
+            );
+
+            main.sub(SubDiagnostic::new(
+                SubDiagnosticSeverity::Info,
+                format!("{}\n{}", "Source", self.file_content),
+            ));
+
+            main
+        }
+    }
 }

crates/ty_ide/src/lib.rs

@@ -33,7 +33,9 @@ pub use document_symbols::document_symbols;
 pub use goto::{goto_declaration, goto_definition, goto_type_definition};
 pub use goto_references::goto_references;
 pub use hover::hover;
-pub use inlay_hints::{InlayHintKind, InlayHintLabel, InlayHintSettings, inlay_hints};
+pub use inlay_hints::{
+    InlayHintKind, InlayHintLabel, InlayHintSettings, InlayHintTextEdit, inlay_hints,
+};
 pub use markup::MarkupKind;
 pub use references::ReferencesMode;
 pub use rename::{can_rename, rename};

crates/ty_ide/src/references.rs

@@ -122,10 +122,10 @@ fn references_for_file(
 ) {
     let parsed = ruff_db::parsed::parsed_module(db, file);
     let module = parsed.load(db);
+    let model = SemanticModel::new(db, file);
 
     let mut finder = LocalReferencesFinder {
-        db,
-        file,
+        model: &model,
         target_definitions,
         references,
         mode,
@@ -157,8 +157,7 @@ fn is_symbol_externally_visible(goto_target: &GotoTarget<'_>) -> bool {
 
 /// AST visitor to find all references to a specific symbol by comparing semantic definitions
 struct LocalReferencesFinder<'a> {
-    db: &'a dyn Db,
-    file: File,
+    model: &'a SemanticModel<'a>,
     tokens: &'a Tokens,
     target_definitions: &'a [NavigationTarget],
     references: &'a mut Vec<ReferenceTarget>,
@@ -227,6 +226,22 @@ impl<'a> SourceOrderVisitor<'a> for LocalReferencesFinder<'a> {
                     self.check_identifier_reference(rest_name);
                 }
             }
+            AnyNodeRef::ExprStringLiteral(string_expr) if self.should_include_declaration() => {
+                // Highlight the sub-AST of a string annotation
+                if let Some((sub_ast, sub_model)) = self.model.enter_string_annotation(string_expr)
+                {
+                    let mut sub_finder = LocalReferencesFinder {
+                        model: &sub_model,
+                        target_definitions: self.target_definitions,
+                        references: self.references,
+                        mode: self.mode,
+                        tokens: sub_ast.tokens(),
+                        target_text: self.target_text,
+                        ancestors: Vec::new(),
+                    };
+                    sub_finder.visit_expr(sub_ast.expr());
+                }
+            }
             AnyNodeRef::Alias(alias) if self.should_include_declaration() => {
                 // Handle import alias declarations
                 if let Some(asname) = &alias.asname {
@@ -285,15 +300,13 @@ impl LocalReferencesFinder<'_> {
         // the node is fine here. Offsets matter only for import statements
         // where the identifier might be a multi-part module name.
         let offset = covering_node.node().start();
-
         if let Some(goto_target) =
-            GotoTarget::from_covering_node(covering_node, offset, self.tokens)
+            GotoTarget::from_covering_node(self.model, covering_node, offset, self.tokens)
         {
             // Get the definitions for this goto target
-            let model = SemanticModel::new(self.db, self.file);
             if let Some(current_definitions_nav) = goto_target
-                .get_definition_targets(&model, ImportAliasResolution::PreserveAliases)
-                .and_then(|definitions| definitions.declaration_targets(self.db))
+                .get_definition_targets(self.model, ImportAliasResolution::PreserveAliases)
+                .and_then(|definitions| definitions.declaration_targets(self.model.db()))
             {
                 let current_definitions: Vec<NavigationTarget> =
                     current_definitions_nav.into_iter().collect();
@@ -302,7 +315,7 @@ impl LocalReferencesFinder<'_> {
                     // Determine if this is a read or write reference
                     let kind = self.determine_reference_kind(covering_node);
                     let target =
-                        ReferenceTarget::new(self.file, covering_node.node().range(), kind);
+                        ReferenceTarget::new(self.model.file(), covering_node.node().range(), kind);
                     self.references.push(target);
                 }
             }

crates/ty_ide/src/rename.rs

@@ -12,7 +12,7 @@ pub fn can_rename(db: &dyn Db, file: File, offset: TextSize) -> Option<ruff_text
     let model = SemanticModel::new(db, file);
 
     // Get the definitions for the symbol at the offset
-    let goto_target = find_goto_target(&module, offset)?;
+    let goto_target = find_goto_target(&model, &module, offset)?;
 
     // Don't allow renaming of import module components
     if matches!(
@@ -59,9 +59,10 @@ pub fn rename(
 ) -> Option<Vec<ReferenceTarget>> {
     let parsed = ruff_db::parsed::parsed_module(db, file);
     let module = parsed.load(db);
+    let model = SemanticModel::new(db, file);
 
     // Get the definitions for the symbol at the offset
-    let goto_target = find_goto_target(&module, offset)?;
+    let goto_target = find_goto_target(&model, &module, offset)?;
 
     // Clients shouldn't call us with an empty new name, but just in case...
     if new_name.is_empty() {
@@ -338,6 +339,162 @@ class DataProcessor:
         ");
     }
 
+    #[test]
+    fn rename_string_annotation1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCla<CURSOR>ss" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @r#"
+        info[rename]: Rename symbol (found 2 locations)
+         --> main.py:2:5
+          |
+        2 | a: "MyClass" = 1
+          |     ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |       -------
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn rename_string_annotation2() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyCl<CURSOR>ass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @r#"
+        info[rename]: Rename symbol (found 2 locations)
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |       -------
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn rename_string_annotation3() {
+        let test = cursor_test(
+            r#"
+        a: "None |<CURSOR> MyClass" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @"Cannot rename");
+    }
+
+    #[test]
+    fn rename_string_annotation4() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass<CURSOR>" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @r#"
+        info[rename]: Rename symbol (found 2 locations)
+         --> main.py:2:12
+          |
+        2 | a: "None | MyClass" = 1
+          |            ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |       -------
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn rename_string_annotation5() {
+        let test = cursor_test(
+            r#"
+        a: "None | MyClass"<CURSOR> = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @"Cannot rename");
+    }
+
+    #[test]
+    fn rename_string_annotation_dangling1() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass |" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @"Cannot rename");
+    }
+
+    #[test]
+    fn rename_string_annotation_dangling2() {
+        let test = cursor_test(
+            r#"
+        a: "MyCl<CURSOR>ass | No" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @r#"
+        info[rename]: Rename symbol (found 2 locations)
+         --> main.py:2:5
+          |
+        2 | a: "MyClass | No" = 1
+          |     ^^^^^^^
+        3 |
+        4 | class MyClass:
+          |       -------
+        5 |     """some docs"""
+          |
+        "#);
+    }
+
+    #[test]
+    fn rename_string_annotation_dangling3() {
+        let test = cursor_test(
+            r#"
+        a: "MyClass | N<CURSOR>o" = 1
+
+        class MyClass:
+            """some docs"""
+        "#,
+        );
+
+        assert_snapshot!(test.rename("MyNewClass"), @"Cannot rename");
+    }
+
     #[test]
     fn test_cannot_rename_import_module_component() {
         // Test that we cannot rename parts of module names in import statements

crates/ty_ide/src/semantic_tokens.rs

@@ -187,9 +187,9 @@ impl Deref for SemanticTokens {
 /// Pass None to get tokens for the entire file.
 pub fn semantic_tokens(db: &dyn Db, file: File, range: Option<TextRange>) -> SemanticTokens {
     let parsed = parsed_module(db, file).load(db);
-    let semantic_model = SemanticModel::new(db, file);
+    let model = SemanticModel::new(db, file);
 
-    let mut visitor = SemanticTokenVisitor::new(&semantic_model, file, range);
+    let mut visitor = SemanticTokenVisitor::new(&model, range);
     visitor.visit_body(parsed.suite());
 
     SemanticTokens::new(visitor.tokens)
@@ -197,8 +197,7 @@ pub fn semantic_tokens(db: &dyn Db, file: File, range: Option<TextRange>) -> Sem
 
 /// AST visitor that collects semantic tokens.
 struct SemanticTokenVisitor<'db> {
-    semantic_model: &'db SemanticModel<'db>,
-    file: File,
+    model: &'db SemanticModel<'db>,
     tokens: Vec<SemanticToken>,
     in_class_scope: bool,
     in_type_annotation: bool,
@@ -207,14 +206,9 @@ struct SemanticTokenVisitor<'db> {
 }
 
 impl<'db> SemanticTokenVisitor<'db> {
-    fn new(
-        semantic_model: &'db SemanticModel<'db>,
-        file: File,
-        range_filter: Option<TextRange>,
-    ) -> Self {
+    fn new(model: &'db SemanticModel<'db>, range_filter: Option<TextRange>) -> Self {
         Self {
-            semantic_model,
-            file,
+            model,
             tokens: Vec::new(),
             in_class_scope: false,
             in_target_creating_definition: false,
@@ -265,7 +259,7 @@ impl<'db> SemanticTokenVisitor<'db> {
 
     fn classify_name(&self, name: &ast::ExprName) -> (SemanticTokenType, SemanticTokenModifier) {
         // First try to classify the token based on its definition kind.
-        let definition = definition_for_name(self.semantic_model.db(), self.file, name);
+        let definition = definition_for_name(self.model, name);
 
         if let Some(definition) = definition {
             let name_str = name.id.as_str();
@@ -275,7 +269,7 @@ impl<'db> SemanticTokenVisitor<'db> {
         }
 
         // Fall back to type-based classification.
-        let ty = name.inferred_type(self.semantic_model);
+        let ty = name.inferred_type(self.model);
         let name_str = name.id.as_str();
         self.classify_from_type_and_name_str(ty, name_str)
     }
@@ -286,7 +280,7 @@ impl<'db> SemanticTokenVisitor<'db> {
         name_str: &str,
     ) -> Option<(SemanticTokenType, SemanticTokenModifier)> {
         let mut modifiers = SemanticTokenModifier::empty();
-        let db = self.semantic_model.db();
+        let db = self.model.db();
         let model = SemanticModel::new(db, definition.file(db));
 
         match definition.kind(db) {
@@ -712,12 +706,12 @@ impl SourceOrderVisitor<'_> for SemanticTokenVisitor<'_> {
                 for alias in &import.names {
                     if let Some(asname) = &alias.asname {
                         // For aliased imports (from X import Y as Z), classify Z based on what Y is
-                        let ty = alias.inferred_type(self.semantic_model);
+                        let ty = alias.inferred_type(self.model);
                         let (token_type, modifiers) = self.classify_from_alias_type(ty, asname);
                         self.add_token(asname, token_type, modifiers);
                     } else {
                         // For direct imports (from X import Y), use semantic classification
-                        let ty = alias.inferred_type(self.semantic_model);
+                        let ty = alias.inferred_type(self.model);
                         let (token_type, modifiers) =
                             self.classify_from_alias_type(ty, &alias.name);
                         self.add_token(&alias.name, token_type, modifiers);
@@ -837,7 +831,7 @@ impl SourceOrderVisitor<'_> for SemanticTokenVisitor<'_> {
                 self.visit_expr(&attr.value);
 
                 // Then add token for the attribute name (e.g., 'path' in 'os.path')
-                let ty = expr.inferred_type(self.semantic_model);
+                let ty = expr.inferred_type(self.model);
                 let (token_type, modifiers) =
                     Self::classify_from_type_for_attribute(ty, &attr.attr);
                 self.add_token(&attr.attr, token_type, modifiers);
@@ -881,6 +875,17 @@ impl SourceOrderVisitor<'_> for SemanticTokenVisitor<'_> {
 
                 self.visit_expr(&named.value);
             }
+            ast::Expr::StringLiteral(string_expr) => {
+                // Highlight the sub-AST of a string annotation
+                if let Some((sub_ast, sub_model)) = self.model.enter_string_annotation(string_expr)
+                {
+                    let mut sub_visitor = SemanticTokenVisitor::new(&sub_model, None);
+                    sub_visitor.visit_expr(sub_ast.expr());
+                    self.tokens.extend(sub_visitor.tokens);
+                } else {
+                    walk_expr(self, expr);
+                }
+            }
             _ => {
                 // For all other expression types, let the default visitor handle them
                 walk_expr(self, expr);
@@ -1061,6 +1066,17 @@ impl SourceOrderVisitor<'_> for SemanticTokenVisitor<'_> {
             }
         }
     }
+
+    fn visit_comprehension(&mut self, comp: &ast::Comprehension) {
+        self.in_target_creating_definition = true;
+        self.visit_expr(&comp.target);
+        self.in_target_creating_definition = false;
+
+        self.visit_expr(&comp.iter);
+        for if_clause in &comp.ifs {
+            self.visit_expr(if_clause);
+        }
+    }
 }
 
 #[cfg(test)]
@@ -1564,6 +1580,50 @@ from mymodule import CONSTANT, my_function, MyClass
         "#);
     }
 
+    #[test]
+    fn test_str_annotation() {
+        let test = SemanticTokenTest::new(
+            r#"
+x: int = 1
+y: "int" = 1
+z = "int"
+w1: "int | str" = "hello"
+w2: "int | sr" = "hello"
+w3: "int | " = "hello"
+w4: "float"
+w5: "float
+"#,
+        );
+
+        let tokens = test.highlight_file();
+
+        assert_snapshot!(test.to_snapshot(&tokens), @r#"
+        "x" @ 1..2: Variable [definition]
+        "int" @ 4..7: Class
+        "1" @ 10..11: Number
+        "y" @ 12..13: Variable [definition]
+        "int" @ 16..19: Class
+        "1" @ 23..24: Number
+        "z" @ 25..26: Variable [definition]
+        "\"int\"" @ 29..34: String
+        "w1" @ 35..37: Variable [definition]
+        "int" @ 40..43: Class
+        "str" @ 46..49: Class
+        "\"hello\"" @ 53..60: String
+        "w2" @ 61..63: Variable [definition]
+        "int" @ 66..69: Class
+        "sr" @ 72..74: Variable
+        "\"hello\"" @ 78..85: String
+        "w3" @ 86..88: Variable [definition]
+        "\"int | \"" @ 90..98: String
+        "\"hello\"" @ 101..108: String
+        "w4" @ 109..111: Variable [definition]
+        "float" @ 114..119: Class
+        "w5" @ 121..123: Variable [definition]
+        "float" @ 126..131: Class
+        "#);
+    }
+
     #[test]
     fn test_attribute_classification() {
         let test = SemanticTokenTest::new(
@@ -2595,6 +2655,50 @@ with open("file.txt") as f:
         "#);
     }
 
+    #[test]
+    fn test_comprehensions() {
+        let test = SemanticTokenTest::new(
+            r#"
+list_comp = [x for x in range(10) if x % 2 == 0]
+set_comp = {x for x in range(10)}
+dict_comp = {k: v for k, v in zip(["a", "b"], [1, 2])}
+generator = (x for x in range(10))
+"#,
+        );
+
+        let tokens = test.highlight_file();
+        assert_snapshot!(test.to_snapshot(&tokens), @r#"
+        "list_comp" @ 1..10: Variable [definition]
+        "x" @ 14..15: Variable
+        "x" @ 20..21: Variable [definition]
+        "range" @ 25..30: Class
+        "10" @ 31..33: Number
+        "x" @ 38..39: Variable
+        "2" @ 42..43: Number
+        "0" @ 47..48: Number
+        "set_comp" @ 50..58: Variable [definition]
+        "x" @ 62..63: Variable
+        "x" @ 68..69: Variable [definition]
+        "range" @ 73..78: Class
+        "10" @ 79..81: Number
+        "dict_comp" @ 84..93: Variable [definition]
+        "k" @ 97..98: Variable
+        "v" @ 100..101: Variable
+        "k" @ 106..107: Variable [definition]
+        "v" @ 109..110: Variable [definition]
+        "zip" @ 114..117: Class
+        "\"a\"" @ 119..122: String
+        "\"b\"" @ 124..127: String
+        "1" @ 131..132: Number
+        "2" @ 134..135: Number
+        "generator" @ 139..148: Variable [definition]
+        "x" @ 152..153: Variable
+        "x" @ 158..159: Variable [definition]
+        "range" @ 163..168: Class
+        "10" @ 169..171: Number
+        "#);
+    }
+
     /// Regression test for <https://github.com/astral-sh/ty/issues/1406>
     #[test]
     fn test_invalid_kwargs() {

crates/ty_ide/src/signature_help.rs

@@ -74,7 +74,7 @@ pub fn signature_help(db: &dyn Db, file: File, offset: TextSize) -> Option<Signa
 
     // Get signature details from the semantic analyzer.
     let signature_details: Vec<CallSignatureDetails<'_>> =
-        call_signature_details(db, &model, call_expr);
+        call_signature_details(&model, call_expr);
 
     if signature_details.is_empty() {
         return None;

crates/ty_ide/src/stub_mapping.rs

@@ -11,12 +11,12 @@ use crate::cached_vendored_root;
 /// other language server providers (like hover, completion, and signature help) to find
 /// docstrings for functions that resolve to stubs.
 pub(crate) struct StubMapper<'db> {
-    db: &'db dyn crate::Db,
+    db: &'db dyn ty_python_semantic::Db,
     cached_vendored_root: Option<SystemPathBuf>,
 }
 
 impl<'db> StubMapper<'db> {
-    pub(crate) fn new(db: &'db dyn crate::Db) -> Self {
+    pub(crate) fn new(db: &'db dyn ty_python_semantic::Db) -> Self {
         let cached_vendored_root = cached_vendored_root(db);
         Self {
             db,

crates/ty_python_semantic/Cargo.toml

@@ -13,6 +13,7 @@ license = { workspace = true }
 [dependencies]
 ruff_db = { workspace = true }
 ruff_annotate_snippets = { workspace = true }
+ruff_diagnostics = { workspace = true }
 ruff_index = { workspace = true, features = ["salsa"] }
 ruff_macros = { workspace = true }
 ruff_memory_usage = { workspace = true }

crates/ty_python_semantic/resources/corpus/classliteral_decorators_cycle.py

@@ -0,0 +1,26 @@
+try:
+    type name_4 = name_1
+finally:
+    from .. import name_3
+
+try:
+    pass
+except* 0:
+    pass
+else:
+    def name_1() -> name_4:
+        pass
+
+    @name_1
+    def name_3():
+        pass
+finally:
+    try:
+        pass
+    except* 0:
+        assert name_3
+    finally:
+
+        @name_3
+        class name_1:
+            pass

crates/ty_python_semantic/resources/corpus/cyclic_reassignment.py

@@ -0,0 +1,5 @@
+class foo[_: foo](object): ...
+
+[_] = (foo,) = foo
+
+def foo(): ...

crates/ty_python_semantic/resources/corpus/cyclic_type_alias.py

@@ -0,0 +1,20 @@
+name_3: Foo = 0
+name_4 = 0
+
+if _0:
+    type name_3 = name_5
+    type name_4 = name_3
+
+_1: name_3
+
+def name_1(_2: name_4):
+    pass
+
+match 0:
+    case name_1._3:
+        pass
+    case 1:
+        type name_5 = name_4
+    case name_5:
+        pass
+name_3 = name_5

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

@@ -35,6 +35,8 @@ bad_nesting: Literal[LiteralString]  # error: [invalid-type-form]
 
 `LiteralString` cannot be parameterized.
 
+<!-- snapshot-diagnostics -->
+
 ```py
 from typing_extensions import LiteralString
 
@@ -42,7 +44,6 @@ from typing_extensions import LiteralString
 a: LiteralString[str]
 
 # error: [invalid-type-form]
-# error: [unresolved-reference] "Name `foo` used when not defined"
 b: LiteralString["foo"]
 ```
 

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

@@ -222,10 +222,10 @@ reveal_type(r)  # revealed: dict[int | str, int | str]
 ## Incorrect collection literal assignments are complained about
 
 ```py
-# error: [invalid-assignment] "Object of type `list[Unknown | int]` is not assignable to `list[str]`"
+# error: [invalid-assignment] "Object of type `list[str | int]` is not assignable to `list[str]`"
 a: list[str] = [1, 2, 3]
 
-# error: [invalid-assignment] "Object of type `set[Unknown | int | str]` is not assignable to `set[int]`"
+# error: [invalid-assignment] "Object of type `set[int | str]` is not assignable to `set[int]`"
 b: set[int] = {1, 2, "3"}
 ```
 
@@ -422,7 +422,7 @@ reveal_type(d)  # revealed: list[int | tuple[int, int]]
 e: list[int] = f(True)
 reveal_type(e)  # revealed: list[int]
 
-# error: [invalid-assignment] "Object of type `list[str]` is not assignable to `list[int]`"
+# error: [invalid-assignment] "Object of type `list[int | str]` is not assignable to `list[int]`"
 g: list[int] = f("a")
 
 # error: [invalid-assignment] "Object of type `list[str]` is not assignable to `tuple[int]`"
@@ -459,12 +459,12 @@ reveal_type(b)  # revealed: TD
 
 # error: [missing-typed-dict-key] "Missing required key 'x' in TypedDict `TD` constructor"
 # error: [invalid-key] "Unknown key "y" for TypedDict `TD`"
-# error: [invalid-assignment] "Object of type `Unknown | dict[Unknown | str, Unknown | int]` is not assignable to `TD`"
+# error: [invalid-assignment] "Object of type `TD | dict[Unknown | str, Unknown | int]` is not assignable to `TD`"
 c: TD = f([{"y": 0}, {"x": 1}])
 
 # error: [missing-typed-dict-key] "Missing required key 'x' in TypedDict `TD` constructor"
 # error: [invalid-key] "Unknown key "y" for TypedDict `TD`"
-# error: [invalid-assignment] "Object of type `Unknown | dict[Unknown | str, Unknown | int]` is not assignable to `TD | None`"
+# error: [invalid-assignment] "Object of type `TD | None | dict[Unknown | str, Unknown | int]` is not assignable to `TD | None`"
 c: TD | None = f([{"y": 0}, {"x": 1}])
 ```
 

crates/ty_python_semantic/resources/mdtest/attributes.md

@@ -2383,6 +2383,34 @@ class B:
 
 reveal_type(B().x)  # revealed: Unknown | Literal[1]
 reveal_type(A().x)  # revealed: Unknown | Literal[1]
+
+class Base:
+    def flip(self) -> "Sub":
+        return Sub()
+
+class Sub(Base):
+    # error: [invalid-method-override]
+    def flip(self) -> "Base":
+        return Base()
+
+class C2:
+    def __init__(self, x: Sub):
+        self.x = x
+
+    def replace_with(self, other: "C2"):
+        self.x = other.x.flip()
+
+reveal_type(C2(Sub()).x)  # revealed: Unknown | Base
+
+class C3:
+    def __init__(self, x: Sub):
+        self.x = [x]
+
+    def replace_with(self, other: "C3"):
+        self.x = [self.x[0].flip()]
+
+# TODO: should be `Unknown | list[Unknown | Sub] | list[Unknown | Base]`
+reveal_type(C3(Sub()).x)  # revealed: Unknown | list[Unknown | Sub] | list[Divergent]
 ```
 
 And cycles between many attributes:
@@ -2432,6 +2460,30 @@ class ManyCycles:
         reveal_type(self.x5)  # revealed: Unknown | int
         reveal_type(self.x6)  # revealed: Unknown | int
         reveal_type(self.x7)  # revealed: Unknown | int
+
+class ManyCycles2:
+    def __init__(self: "ManyCycles2"):
+        self.x1 = [0]
+        self.x2 = [1]
+        self.x3 = [1]
+
+    def f1(self: "ManyCycles2"):
+        # TODO: should be Unknown | list[Unknown | int] | list[Divergent]
+        reveal_type(self.x3)  # revealed: Unknown | list[Unknown | int] | list[Divergent] | list[Divergent]
+
+        self.x1 = [self.x2] + [self.x3]
+        self.x2 = [self.x1] + [self.x3]
+        self.x3 = [self.x1] + [self.x2]
+
+    def f2(self: "ManyCycles2"):
+        self.x1 = self.x2 + self.x3
+        self.x2 = self.x1 + self.x3
+        self.x3 = self.x1 + self.x2
+
+    def f3(self: "ManyCycles2"):
+        self.x1 = self.x2 + self.x3
+        self.x2 = self.x1 + self.x3
+        self.x3 = self.x1 + self.x2
 ```
 
 This case additionally tests our union/intersection simplification logic:
@@ -2611,12 +2663,18 @@ reveal_type(Answer.__members__)  # revealed: MappingProxyType[str, Unknown]
 
 ## Divergent inferred implicit instance attribute types
 
+If an implicit attribute is defined recursively and type inference diverges, the divergent part is
+filled in with the dynamic type `Divergent`. Types containing `Divergent` can be seen as "cheap"
+recursive types: they are not true recursive types based on recursive type theory, so no unfolding
+is performed when you use them.
+
 ```py
 class C:
     def f(self, other: "C"):
         self.x = (other.x, 1)
 
 reveal_type(C().x)  # revealed: Unknown | tuple[Divergent, Literal[1]]
+reveal_type(C().x[0])  # revealed: Unknown | Divergent
 ```
 
 This also works if the tuple is not constructed directly:
@@ -2655,11 +2713,11 @@ And it also works for homogeneous tuples:
 def make_homogeneous_tuple(x: T) -> tuple[T, ...]:
     return (x, x)
 
-class E:
-    def f(self, other: "E"):
+class F:
+    def f(self, other: "F"):
         self.x = make_homogeneous_tuple(other.x)
 
-reveal_type(E().x)  # revealed: Unknown | tuple[Divergent, ...]
+reveal_type(F().x)  # revealed: Unknown | tuple[Divergent, ...]
 ```
 
 ## Attributes of standard library modules that aren't yet defined
@@ -2711,10 +2769,10 @@ We give special diagnostics for this common case too:
 import foo
 import baz
 
-# error: [unresolved-attribute]
-reveal_type(foo.bar)  # revealed: Unknown
-# error: [unresolved-attribute]
-reveal_type(baz.bar)  # revealed: Unknown
+# error: [possibly-missing-attribute]
+reveal_type(foo.bar)  # revealed: <module 'foo.bar'>
+# error: [possibly-missing-attribute]
+reveal_type(baz.bar)  # revealed: <module 'baz.bar'>
 ```
 
 ## References

crates/ty_python_semantic/resources/mdtest/bidirectional.md

@@ -268,8 +268,8 @@ class A:
 
 A(f(1))
 
-# error: [invalid-argument-type] "Argument to function `__new__` is incorrect: Expected `list[int | str]`, found `list[list[Unknown]]`"
-# error: [invalid-argument-type] "Argument to bound method `__init__` is incorrect: Expected `list[int | None]`, found `list[list[Unknown]]`"
+# error: [invalid-argument-type] "Argument to function `__new__` is incorrect: Expected `list[int | str]`, found `list[int | None | list[Unknown]] & list[int | str | list[Unknown]] & list[list[Unknown]]`"
+# error: [invalid-argument-type] "Argument to bound method `__init__` is incorrect: Expected `list[int | None]`, found `list[int | None | list[Unknown]] & list[int | str | list[Unknown]] & list[list[Unknown]]`"
 A(f([]))
 ```
 

crates/ty_python_semantic/resources/mdtest/call/builtins.md

@@ -57,7 +57,7 @@ type("Foo", Base, {})
 # error: [invalid-argument-type] "Argument to class `type` is incorrect: Expected `tuple[type, ...]`, found `tuple[Literal[1], Literal[2]]`"
 type("Foo", (1, 2), {})
 
-# error: [invalid-argument-type] "Argument to class `type` is incorrect: Expected `dict[str, Any]`, found `dict[Unknown | bytes, Unknown | int]`"
+# error: [invalid-argument-type] "Argument to class `type` is incorrect: Expected `dict[str, Any]`, found `dict[str | bytes, Any]`"
 type("Foo", (Base,), {b"attr": 1})
 ```
 

crates/ty_python_semantic/resources/mdtest/call/callables_as_descriptors.md

@@ -237,4 +237,26 @@ class Matrix:
 Matrix() < Matrix()
 ```
 
+## `self`-binding behaviour of function-like `Callable`s
+
+Binding the `self` parameter of a function-like `Callable` creates a new `Callable` that is also
+function-like:
+
+`main.py`:
+
+```py
+from typing import Callable
+
+def my_lossy_decorator(fn: Callable[..., int]) -> Callable[..., int]:
+    return fn
+
+class MyClass:
+    @my_lossy_decorator
+    def method(self) -> int:
+        return 42
+
+reveal_type(MyClass().method)  # revealed: (...) -> int
+reveal_type(MyClass().method.__name__)  # revealed: str
+```
+
 [`tensorbase`]: https://github.com/pytorch/pytorch/blob/f3913ea641d871f04fa2b6588a77f63efeeb9f10/torch/_tensor.py#L1084-L1092

crates/ty_python_semantic/resources/mdtest/call/union.md

@@ -277,6 +277,6 @@ def _(flag: bool):
     x = f({"x": 1})
     reveal_type(x)  # revealed: int
 
-    # error: [invalid-argument-type] "Argument to function `f` is incorrect: Expected `T`, found `dict[Unknown | str, Unknown | int]`"
+    # error: [invalid-argument-type] "Argument to function `f` is incorrect: Expected `T`, found `dict[str, int] & dict[Unknown | str, Unknown | int]`"
     f({"y": 1})
 ```

crates/ty_python_semantic/resources/mdtest/cycle.md

@@ -32,6 +32,55 @@ reveal_type(p.x)  # revealed: Unknown | int
 reveal_type(p.y)  # revealed: Unknown | int
 ```
 
+## Self-referential bare type alias
+
+```toml
+[environment]
+python-version = "3.12"  # typing.TypeAliasType
+```
+
+```py
+from typing import Union, TypeAliasType, Sequence, Mapping
+
+A = list["A" | None]
+
+def f(x: A):
+    # TODO: should be `list[A | None]`?
+    reveal_type(x)  # revealed: list[Divergent]
+    # TODO: should be `A | None`?
+    reveal_type(x[0])  # revealed: Divergent
+
+JSONPrimitive = Union[str, int, float, bool, None]
+JSONValue = TypeAliasType("JSONValue", 'Union[JSONPrimitive, Sequence["JSONValue"], Mapping[str, "JSONValue"]]')
+```
+
+## Self-referential legacy type variables
+
+```py
+from typing import Generic, TypeVar
+
+B = TypeVar("B", bound="Base")
+
+class Base(Generic[B]):
+    pass
+
+T = TypeVar("T", bound="Foo[int]")
+
+class Foo(Generic[T]): ...
+```
+
+## Self-referential PEP-695 type variables
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+```py
+class Node[T: "Node[int]"]:
+    pass
+```
+
 ## Parameter default values
 
 This is a regression test for <https://github.com/astral-sh/ty/issues/1402>. When a parameter has a

crates/ty_python_semantic/resources/mdtest/diagnostics/same_names.md

@@ -171,7 +171,7 @@ class Config:
 import generic_a
 import generic_b
 
-# TODO should be error: [invalid-assignment] "Object of type `<class 'generic_b.Container[int]'>` is not assignable to `type[generic_a.Container[int]]`"
+# error: [invalid-assignment] "Object of type `<class 'generic_b.Container[int]'>` is not assignable to `type[generic_a.Container[int]]`"
 container: type[generic_a.Container[int]] = generic_b.Container[int]
 ```
 

crates/ty_python_semantic/resources/mdtest/directives/assert_never.md

@@ -124,6 +124,10 @@ def match_singletons_error(obj: Literal[1, "a"] | None):
         case None:
             pass
         case _ as obj:
-            # TODO: We should emit an error here: `Literal["a"]` is not `Never`.
+            # TODO: We should emit an error here, but the message should
+            # show the type `Literal["a"]` instead of `@Todo(…)`. We only
+            # assert on the first part of the message because the `@Todo`
+            # message is not available in release mode builds.
+            # error: [type-assertion-failure] "Type `@Todo"
             assert_never(obj)
 ```

crates/ty_python_semantic/resources/mdtest/generics/legacy/classes.md

@@ -273,7 +273,7 @@ class C(Generic[T]):
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 ```
 
@@ -289,7 +289,7 @@ class C(Generic[T]):
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 ```
 
@@ -308,7 +308,7 @@ class C(Generic[T]):
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 ```
 
@@ -327,7 +327,7 @@ class C(Generic[T]):
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 
 class D(Generic[T]):
@@ -338,7 +338,7 @@ class D(Generic[T]):
 
 reveal_type(D(1))  # revealed: D[int]
 
-# error: [invalid-assignment] "Object of type `D[str]` is not assignable to `D[int]`"
+# error: [invalid-assignment] "Object of type `D[int | str]` is not assignable to `D[int]`"
 wrong_innards: D[int] = D("five")
 ```
 
@@ -454,7 +454,7 @@ reveal_type(C(1, 1))  # revealed: C[int]
 reveal_type(C(1, "string"))  # revealed: C[int]
 reveal_type(C(1, True))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five", 1)
 ```
 
@@ -732,6 +732,14 @@ class Base(Generic[T]): ...
 class Sub(Base["Sub"]): ...
 
 reveal_type(Sub)  # revealed: <class 'Sub'>
+
+U = TypeVar("U")
+
+class Base2(Generic[T, U]): ...
+
+# TODO: no error
+# error: [unsupported-base] "Unsupported class base with type `<class 'Base2[Sub2, U@Sub2]'> | <class 'Base2[Sub2[Unknown], U@Sub2]'>`"
+class Sub2(Base2["Sub2", U]): ...
 ```
 
 #### Without string forward references
@@ -756,6 +764,8 @@ from typing_extensions import Generic, TypeVar
 
 T = TypeVar("T")
 
+# TODO: no error "Unsupported class base with type `<class 'list[Derived[T@Derived]]'> | <class 'list[@Todo]'>`"
+# error: [unsupported-base]
 class Derived(list[Derived[T]], Generic[T]): ...
 ```
 

crates/ty_python_semantic/resources/mdtest/generics/pep695/classes.md

@@ -249,7 +249,7 @@ class C[T]:
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 ```
 
@@ -263,7 +263,7 @@ class C[T]:
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 ```
 
@@ -280,7 +280,7 @@ class C[T]:
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 ```
 
@@ -297,7 +297,7 @@ class C[T]:
 
 reveal_type(C(1))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five")
 
 class D[T]:
@@ -310,7 +310,7 @@ class D[T]:
 
 reveal_type(D(1))  # revealed: D[int]
 
-# error: [invalid-assignment] "Object of type `D[str]` is not assignable to `D[int]`"
+# error: [invalid-assignment] "Object of type `D[int | str]` is not assignable to `D[int]`"
 wrong_innards: D[int] = D("five")
 ```
 
@@ -395,7 +395,7 @@ reveal_type(C(1, 1))  # revealed: C[int]
 reveal_type(C(1, "string"))  # revealed: C[int]
 reveal_type(C(1, True))  # revealed: C[int]
 
-# error: [invalid-assignment] "Object of type `C[str]` is not assignable to `C[int]`"
+# error: [invalid-assignment] "Object of type `C[int | str]` is not assignable to `C[int]`"
 wrong_innards: C[int] = C("five", 1)
 ```
 

crates/ty_python_semantic/resources/mdtest/generics/specialize_constrained.md

@@ -22,8 +22,10 @@ from ty_extensions import ConstraintSet, generic_context
 # fmt: off
 
 def unbounded[T]():
-    # revealed: ty_extensions.Specialization[T@unbounded = object]
+    # revealed: ty_extensions.Specialization[T@unbounded = Unknown]
     reveal_type(generic_context(unbounded).specialize_constrained(ConstraintSet.always()))
+    # revealed: ty_extensions.Specialization[T@unbounded = object]
+    reveal_type(generic_context(unbounded).specialize_constrained(ConstraintSet.range(Never, T, object)))
     # revealed: None
     reveal_type(generic_context(unbounded).specialize_constrained(ConstraintSet.never()))
 
@@ -88,6 +90,7 @@ that makes the test succeed.
 from typing import Any
 
 def bounded_by_gradual[T: Any]():
+    # TODO: revealed: ty_extensions.Specialization[T@bounded_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@bounded_by_gradual = object]
     reveal_type(generic_context(bounded_by_gradual).specialize_constrained(ConstraintSet.always()))
     # revealed: None
@@ -168,12 +171,16 @@ from typing import Any
 # fmt: off
 
 def constrained_by_gradual[T: (Base, Any)]():
+    # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Unknown]
+    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
+    reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.always()))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = object]
-    reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.always()))
+    reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, object)))
     # revealed: None
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.never()))
 
+    # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, Base)))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
@@ -181,14 +188,14 @@ def constrained_by_gradual[T: (Base, Any)]():
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, Unrelated)))
 
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
-    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Super]
+    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Never, T, Super)))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Super]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Super, T, Super)))
 
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
-    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = object]
+    # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Base]
     reveal_type(generic_context(constrained_by_gradual).specialize_constrained(ConstraintSet.range(Sub, T, object)))
     # TODO: revealed: ty_extensions.Specialization[T@constrained_by_gradual = Any]
     # revealed: ty_extensions.Specialization[T@constrained_by_gradual = Sub]
@@ -288,7 +295,7 @@ class Unrelated: ...
 # fmt: off
 
 def mutually_bound[T: Base, U]():
-    # revealed: ty_extensions.Specialization[T@mutually_bound = Base, U@mutually_bound = object]
+    # revealed: ty_extensions.Specialization[T@mutually_bound = Base, U@mutually_bound = Unknown]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.always()))
     # revealed: None
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.never()))
@@ -296,7 +303,7 @@ def mutually_bound[T: Base, U]():
     # revealed: ty_extensions.Specialization[T@mutually_bound = Base, U@mutually_bound = Base]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.range(Never, U, T)))
 
-    # revealed: ty_extensions.Specialization[T@mutually_bound = Sub, U@mutually_bound = object]
+    # revealed: ty_extensions.Specialization[T@mutually_bound = Sub, U@mutually_bound = Unknown]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.range(Never, T, Sub)))
     # revealed: ty_extensions.Specialization[T@mutually_bound = Sub, U@mutually_bound = Sub]
     reveal_type(generic_context(mutually_bound).specialize_constrained(ConstraintSet.range(Never, T, Sub) & ConstraintSet.range(Never, U, T)))

crates/ty_python_semantic/resources/mdtest/import/cyclic.md

@@ -38,7 +38,7 @@ See: <https://github.com/astral-sh/ty/issues/113>
 from pkg.sub import A
 
 # TODO: This should be `<class 'A'>`
-reveal_type(A)  # revealed: Never
+reveal_type(A)  # revealed: Divergent
 ```
 
 `pkg/outer.py`:

crates/ty_python_semantic/resources/mdtest/import/nonstandard_conventions.md

@@ -60,8 +60,8 @@ Y: int = 47
 import mypackage
 
 reveal_type(mypackage.imported.X)  # revealed: int
-# error: [unresolved-attribute] "Submodule `fails` may not be available"
-reveal_type(mypackage.fails.Y)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `fails` may not be available"
+reveal_type(mypackage.fails.Y)  # revealed: int
 ```
 
 ### In Non-Stub
@@ -90,8 +90,8 @@ Y: int = 47
 import mypackage
 
 reveal_type(mypackage.imported.X)  # revealed: int
-# error: [unresolved-attribute] "Submodule `fails` may not be available"
-reveal_type(mypackage.fails.Y)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `fails` may not be available"
+reveal_type(mypackage.fails.Y)  # revealed: int
 ```
 
 ## Absolute `from` Import of Direct Submodule in `__init__`
@@ -125,8 +125,8 @@ Y: int = 47
 import mypackage
 
 reveal_type(mypackage.imported.X)  # revealed: int
-# error: [unresolved-attribute] "Submodule `fails` may not be available"
-reveal_type(mypackage.fails.Y)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `fails` may not be available"
+reveal_type(mypackage.fails.Y)  # revealed: int
 ```
 
 ### In Non-Stub
@@ -155,8 +155,8 @@ Y: int = 47
 import mypackage
 
 reveal_type(mypackage.imported.X)  # revealed: int
-# error: [unresolved-attribute] "Submodule `fails` may not be available"
-reveal_type(mypackage.fails.Y)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `fails` may not be available"
+reveal_type(mypackage.fails.Y)  # revealed: int
 ```
 
 ## Import of Direct Submodule in `__init__`
@@ -184,8 +184,8 @@ X: int = 42
 import mypackage
 
 # TODO: this could work and would be nice to have?
-# error: [unresolved-attribute] "Submodule `imported` may not be available"
-reveal_type(mypackage.imported.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `imported` may not be available"
+reveal_type(mypackage.imported.X)  # revealed: int
 ```
 
 ### In Non-Stub
@@ -208,8 +208,8 @@ X: int = 42
 import mypackage
 
 # TODO: this could work and would be nice to have
-# error: [unresolved-attribute] "Submodule `imported` may not be available"
-reveal_type(mypackage.imported.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `imported` may not be available"
+reveal_type(mypackage.imported.X)  # revealed: int
 ```
 
 ## Relative `from` Import of Nested Submodule in `__init__`
@@ -242,10 +242,10 @@ X: int = 42
 import mypackage
 
 reveal_type(mypackage.submodule)  # revealed: <module 'mypackage.submodule'>
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested)  # revealed: <module 'mypackage.submodule.nested'>
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested.X)  # revealed: int
 # error: [unresolved-attribute] "has no member `nested`"
 reveal_type(mypackage.nested)  # revealed: Unknown
 # error: [unresolved-attribute] "has no member `nested`"
@@ -280,10 +280,10 @@ import mypackage
 
 reveal_type(mypackage.submodule)  # revealed: <module 'mypackage.submodule'>
 # TODO: this would be nice to support
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested)  # revealed: <module 'mypackage.submodule.nested'>
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested.X)  # revealed: int
 reveal_type(mypackage.nested)  # revealed: <module 'mypackage.submodule.nested'>
 reveal_type(mypackage.nested.X)  # revealed: int
 ```
@@ -318,10 +318,10 @@ X: int = 42
 import mypackage
 
 reveal_type(mypackage.submodule)  # revealed: <module 'mypackage.submodule'>
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested)  # revealed: <module 'mypackage.submodule.nested'>
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested.X)  # revealed: int
 # error: [unresolved-attribute] "has no member `nested`"
 reveal_type(mypackage.nested)  # revealed: Unknown
 # error: [unresolved-attribute] "has no member `nested`"
@@ -356,10 +356,10 @@ import mypackage
 
 reveal_type(mypackage.submodule)  # revealed: <module 'mypackage.submodule'>
 # TODO: this would be nice to support
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `nested` may not be available"
-reveal_type(mypackage.submodule.nested.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested)  # revealed: <module 'mypackage.submodule.nested'>
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested.X)  # revealed: int
 reveal_type(mypackage.nested)  # revealed: <module 'mypackage.submodule.nested'>
 reveal_type(mypackage.nested.X)  # revealed: int
 ```
@@ -393,12 +393,14 @@ X: int = 42
 ```py
 import mypackage
 
-# error: [unresolved-attribute] "Submodule `submodule` may not be available"
-reveal_type(mypackage.submodule)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `submodule` may not be available"
-reveal_type(mypackage.submodule.nested)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `submodule` may not be available"
-reveal_type(mypackage.submodule.nested.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `submodule` may not be available"
+reveal_type(mypackage.submodule)  # revealed: <module 'mypackage.submodule'>
+# error: [possibly-missing-attribute] "Submodule `submodule` may not be available"
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested)  # revealed: <module 'mypackage.submodule.nested'>
+# error: [possibly-missing-attribute] "Submodule `submodule` may not be available"
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested.X)  # revealed: int
 ```
 
 ### In Non-Stub
@@ -429,12 +431,14 @@ X: int = 42
 import mypackage
 
 # TODO: this would be nice to support
-# error: [unresolved-attribute] "Submodule `submodule` may not be available"
-reveal_type(mypackage.submodule)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `submodule` may not be available"
-reveal_type(mypackage.submodule.nested)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `submodule` may not be available"
-reveal_type(mypackage.submodule.nested.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `submodule` may not be available"
+reveal_type(mypackage.submodule)  # revealed: <module 'mypackage.submodule'>
+# error: [possibly-missing-attribute] "Submodule `submodule` may not be available"
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested)  # revealed: <module 'mypackage.submodule.nested'>
+# error: [possibly-missing-attribute] "Submodule `submodule` may not be available"
+# error: [possibly-missing-attribute] "Submodule `nested` may not be available"
+reveal_type(mypackage.submodule.nested.X)  # revealed: int
 ```
 
 ## Relative `from` Import of Direct Submodule in `__init__`, Mismatched Alias
@@ -460,8 +464,8 @@ X: int = 42
 ```py
 import mypackage
 
-# error: [unresolved-attribute] "Submodule `imported` may not be available"
-reveal_type(mypackage.imported.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `imported` may not be available"
+reveal_type(mypackage.imported.X)  # revealed: int
 # error: [unresolved-attribute] "has no member `imported_m`"
 reveal_type(mypackage.imported_m.X)  # revealed: Unknown
 ```
@@ -486,8 +490,8 @@ X: int = 42
 import mypackage
 
 # TODO: this would be nice to support, as it works at runtime
-# error: [unresolved-attribute] "Submodule `imported` may not be available"
-reveal_type(mypackage.imported.X)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `imported` may not be available"
+reveal_type(mypackage.imported.X)  # revealed: int
 reveal_type(mypackage.imported_m.X)  # revealed: int
 ```
 
@@ -647,8 +651,8 @@ reveal_type(mypackage.imported.X)  # revealed: int
 
 ## `from` Import of Other Package's Submodule
 
-`from mypackage import submodule` from outside the package is not modeled as a side-effect on
-`mypackage`, even in the importing file (this could be changed!).
+`from mypackage import submodule` and `from mypackage.submodule import not_a_submodule` from outside
+the package are both modeled as a side-effects on `mypackage`.
 
 ### In Stub
 
@@ -663,18 +667,28 @@ reveal_type(mypackage.imported.X)  # revealed: int
 X: int = 42
 ```
 
+`package2/__init__.pyi`:
+
+```pyi
+```
+
+`package2/submodule.pyi`:
+
+```pyi
+not_a_submodule: int
+```
+
 `main.py`:
 
 ```py
 import mypackage
+import package2
 from mypackage import imported
+from package2.submodule import not_a_submodule
 
 reveal_type(imported.X)  # revealed: int
-
-# TODO: this would be nice to support, but it's dangerous with available_submodule_attributes
-# for details, see: https://github.com/astral-sh/ty/issues/1488
-# error: [unresolved-attribute] "Submodule `imported` may not be available"
-reveal_type(mypackage.imported.X)  # revealed: Unknown
+reveal_type(mypackage.imported.X)  # revealed: int
+reveal_type(package2.submodule.not_a_submodule)  # revealed: int
 ```
 
 ### In Non-Stub
@@ -690,17 +704,28 @@ reveal_type(mypackage.imported.X)  # revealed: Unknown
 X: int = 42
 ```
 
+`package2/__init__.py`:
+
+```py
+```
+
+`package2/submodule.py`:
+
+```py
+not_a_submodule: int
+```
+
 `main.py`:
 
 ```py
 import mypackage
+import package2
 from mypackage import imported
+from package2.submodule import not_a_submodule
 
 reveal_type(imported.X)  # revealed: int
-
-# TODO: this would be nice to support, as it works at runtime
-# error: [unresolved-attribute] "Submodule `imported` may not be available"
-reveal_type(mypackage.imported.X)  # revealed: Unknown
+reveal_type(mypackage.imported.X)  # revealed: int
+reveal_type(package2.submodule.not_a_submodule)  # revealed: int
 ```
 
 ## `from` Import of Sibling Module
@@ -737,8 +762,8 @@ from mypackage import imported
 reveal_type(imported.X)  # revealed: int
 # error: [unresolved-attribute] "has no member `fails`"
 reveal_type(imported.fails.Y)  # revealed: Unknown
-# error: [unresolved-attribute] "Submodule `fails` may not be available"
-reveal_type(mypackage.fails.Y)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `fails` may not be available"
+reveal_type(mypackage.fails.Y)  # revealed: int
 ```
 
 ### In Non-Stub
@@ -770,8 +795,8 @@ from mypackage import imported
 
 reveal_type(imported.X)  # revealed: int
 reveal_type(imported.fails.Y)  # revealed: int
-# error: [unresolved-attribute] "Submodule `fails`"
-reveal_type(mypackage.fails.Y)  # revealed: Unknown
+# error: [possibly-missing-attribute] "Submodule `fails`"
+reveal_type(mypackage.fails.Y)  # revealed: int
 ```
 
 ## Fractal Re-export Nameclash Problems
@@ -859,6 +884,48 @@ from mypackage import funcmod
 x = funcmod(1)
 ```
 
+## A Tale of Two Modules
+
+`from typing import TYPE_CHECKING` has side-effects???
+
+### In Stub
+
+`mypackage/__init__.py`:
+
+```py
+from .conflicted.b import x
+```
+
+`mypackage/conflicted/__init__.py`:
+
+`mypackage/conflicted/other1/__init__.py`:
+
+```py
+x: int = 1
+```
+
+`mypackage/conflicted/b/__init__.py`:
+
+```py
+x: int = 1
+```
+
+`mypackage/conflicted/b/c/__init__.py`:
+
+```py
+y: int = 2
+```
+
+`main.py`:
+
+```py
+from typing import TYPE_CHECKING
+from mypackage.conflicted.other1 import x as x1
+import mypackage.conflicted.b.c
+
+reveal_type(mypackage.conflicted.b.c.y)  # revealed: int
+```
+
 ## Re-export Nameclash Problems In Functions
 
 `from` imports in an `__init__.py` at file scope should be visible to functions defined in the file:

crates/ty_python_semantic/resources/mdtest/import/relative.md

@@ -247,8 +247,8 @@ X: int = 42
 from . import foo
 import package
 
-# error: [unresolved-attribute]
-reveal_type(package.foo.X)  # revealed: Unknown
+# error: [possibly-missing-attribute]
+reveal_type(package.foo.X)  # revealed: int
 ```
 
 ## Relative imports at the top of a search path

crates/ty_python_semantic/resources/mdtest/import/tracking.md

@@ -116,3 +116,43 @@ b = 1
 
 ```py
 ```
+
+## Submodule is loaded in a non-global scope
+
+We recognise submodules as being available as attributes even if they are loaded in a function
+scope. The function might never be executed, which means that the submodule might never be loaded;
+however, we prefer to prioritise avoiding false positives over catching all possible errors here.
+
+`a/b.py`:
+
+```py
+```
+
+`a/c.py`:
+
+```py
+d = 42
+```
+
+`a/e/f.py`:
+
+```py
+```
+
+`main.py`:
+
+```py
+import a
+
+def f():
+    import a.b
+    from a.c import d
+    from a.e import f
+
+f()
+
+reveal_type(a.b)  # revealed: <module 'a.b'>
+reveal_type(a.c)  # revealed: <module 'a.c'>
+reveal_type(a.e)  # revealed: <module 'a.e'>
+reveal_type(a.e.f)  # revealed: <module 'a.e.f'>
+```

crates/ty_python_semantic/resources/mdtest/liskov.md

@@ -523,3 +523,63 @@ class Baz(NamedTuple):
 class Spam(Baz):
     def _asdict(self) -> tuple[int, ...]: ...  # error: [invalid-method-override]
 ```
+
+## Staticmethods and classmethods
+
+Methods decorated with `@staticmethod` or `@classmethod` are checked in much the same way as other
+methods.
+
+<!-- snapshot-diagnostics -->
+
+```pyi
+class Parent:
+    def instance_method(self, x: int) -> int: ...
+    @classmethod
+    def class_method(cls, x: int) -> int: ...
+    @staticmethod
+    def static_method(x: int) -> int: ...
+
+class BadChild1(Parent):
+    @staticmethod
+    def instance_method(self, x: int) -> int: ...  # error: [invalid-method-override]
+    # TODO: we should emit `invalid-method-override` here.
+    # Although the method has the same signature as `Parent.class_method`
+    # when accessed on instances, it does not have the same signature as
+    # `Parent.class_method` when accessed on the class object itself
+    def class_method(cls, x: int) -> int: ...
+    def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+
+class BadChild2(Parent):
+    # TODO: we should emit `invalid-method-override` here.
+    # Although the method has the same signature as `Parent.class_method`
+    # when accessed on instances, it does not have the same signature as
+    # `Parent.class_method` when accessed on the class object itself.
+    #
+    # Note that whereas `BadChild1.class_method` is reported as a Liskov violation by
+    # mypy, pyright and pyrefly, pyright is the only one of those three to report a
+    # Liskov violation on this method as of 2025-11-23.
+    @classmethod
+    def instance_method(self, x: int) -> int: ...
+    @staticmethod
+    def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+    @classmethod
+    def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+
+class BadChild3(Parent):
+    @classmethod
+    def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+    @staticmethod
+    def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+
+class GoodChild1(Parent):
+    @classmethod
+    def class_method(cls, x: int) -> int: ...
+    @staticmethod
+    def static_method(x: int) -> int: ...
+
+class GoodChild2(Parent):
+    @classmethod
+    def class_method(cls, x: object) -> bool: ...
+    @staticmethod
+    def static_method(x: object) -> bool: ...
+```

crates/ty_python_semantic/resources/mdtest/override.md

@@ -0,0 +1,314 @@
+# `typing.override`
+
+## Basics
+
+Decorating a method with `typing.override` decorator is an explicit indication to a type checker
+that the method is intended to override a method on a superclass. If the decorated method does not
+in fact override anything, a type checker should report a diagnostic on that method.
+
+<!-- snapshot-diagnostics -->
+
+```pyi
+from typing_extensions import override, Callable, TypeVar
+
+def lossy_decorator(fn: Callable) -> Callable: ...
+
+class A:
+    @override
+    def __repr__(self): ...  # fine: overrides `object.__repr__`
+
+class Parent:
+    def foo(self): ...
+    @property
+    def my_property1(self) -> int: ...
+    @property
+    def my_property2(self) -> int: ...
+    baz = None
+    @classmethod
+    def class_method1(cls) -> int: ...
+    @staticmethod
+    def static_method1() -> int: ...
+    @classmethod
+    def class_method2(cls) -> int: ...
+    @staticmethod
+    def static_method2() -> int: ...
+    @lossy_decorator
+    def decorated_1(self): ...
+    @lossy_decorator
+    def decorated_2(self): ...
+    @lossy_decorator
+    def decorated_3(self): ...
+
+class Child(Parent):
+    @override
+    def foo(self): ...  # fine: overrides `Parent.foo`
+    @property
+    @override
+    def my_property1(self) -> int: ...  # fine: overrides `Parent.my_property1`
+    @override
+    @property
+    def my_property2(self) -> int: ...  # fine: overrides `Parent.my_property2`
+    @override
+    def baz(self): ...  # fine: overrides `Parent.baz`
+    @classmethod
+    @override
+    def class_method1(cls) -> int: ...  # fine: overrides `Parent.class_method1`
+    @staticmethod
+    @override
+    def static_method1() -> int: ...  # fine: overrides `Parent.static_method1`
+    @override
+    @classmethod
+    def class_method2(cls) -> int: ...  # fine: overrides `Parent.class_method2`
+    @override
+    @staticmethod
+    def static_method2() -> int: ...  # fine: overrides `Parent.static_method2`
+    @override
+    def decorated_1(self): ...  # fine: overrides `Parent.decorated_1`
+    @override
+    @lossy_decorator
+    def decorated_2(self): ...  # fine: overrides `Parent.decorated_2`
+    @lossy_decorator
+    @override
+    def decorated_3(self): ...  # fine: overrides `Parent.decorated_3`
+
+class OtherChild(Parent): ...
+
+class Grandchild(OtherChild):
+    @override
+    def foo(self): ...  # fine: overrides `Parent.foo`
+    @override
+    @property
+    def bar(self) -> int: ...  # fine: overrides `Parent.bar`
+    @override
+    def baz(self): ...  # fine: overrides `Parent.baz`
+    @classmethod
+    @override
+    def class_method1(cls) -> int: ...  # fine: overrides `Parent.class_method1`
+    @staticmethod
+    @override
+    def static_method1() -> int: ...  # fine: overrides `Parent.static_method1`
+    @override
+    @classmethod
+    def class_method2(cls) -> int: ...  # fine: overrides `Parent.class_method2`
+    @override
+    @staticmethod
+    def static_method2() -> int: ...  # fine: overrides `Parent.static_method2`
+    @override
+    def decorated_1(self): ...  # fine: overrides `Parent.decorated_1`
+    @override
+    @lossy_decorator
+    def decorated_2(self): ...  # fine: overrides `Parent.decorated_2`
+    @lossy_decorator
+    @override
+    def decorated_3(self): ...  # fine: overrides `Parent.decorated_3`
+
+class Invalid:
+    @override
+    def ___reprrr__(self): ...  # error: [invalid-explicit-override]
+    @override
+    @classmethod
+    def foo(self): ...  # error: [invalid-explicit-override]
+    @classmethod
+    @override
+    def bar(self): ...  # error: [invalid-explicit-override]
+    @staticmethod
+    @override
+    def baz(): ...  # error: [invalid-explicit-override]
+    @override
+    @staticmethod
+    def eggs(): ...  # error: [invalid-explicit-override]
+    @property
+    @override
+    def bad_property1(self) -> int: ...  # TODO: should emit `invalid-explicit-override` here
+    @override
+    @property
+    def bad_property2(self) -> int: ...  # TODO: should emit `invalid-explicit-override` here
+    @lossy_decorator
+    @override
+    def lossy(self): ...  # TODO: should emit `invalid-explicit-override` here
+    @override
+    @lossy_decorator
+    def lossy2(self): ...  # TODO: should emit `invalid-explicit-override` here
+
+# TODO: all overrides in this class should cause us to emit *Liskov* violations,
+# but not `@override` violations
+class LiskovViolatingButNotOverrideViolating(Parent):
+    @override
+    @property
+    def foo(self) -> int: ...
+    @override
+    def my_property1(self) -> int: ...
+    @staticmethod
+    @override
+    def class_method1() -> int: ...
+    @classmethod
+    @override
+    def static_method1(cls) -> int: ...
+
+# Diagnostic edge case: `override` is very far away from the method definition in the source code:
+
+T = TypeVar("T")
+
+def identity(x: T) -> T: ...
+
+class Foo:
+    @override
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    @identity
+    def bar(self): ...  # error: [invalid-explicit-override]
+```
+
+## Overloads
+
+The typing spec states that for an overloaded method, `@override` should only be applied to the
+implementation function. However, we nonetheless respect the decorator in this situation, even
+though we also emit `invalid-overload` on these methods.
+
+```py
+from typing_extensions import override, overload
+
+class Spam:
+    @overload
+    def foo(self, x: str) -> str: ...
+    @overload
+    def foo(self, x: int) -> int: ...
+    @override
+    def foo(self, x: str | int) -> str | int:  # error: [invalid-explicit-override]
+        return x
+
+    @overload
+    @override
+    def bar(self, x: str) -> str: ...
+    @overload
+    @override
+    def bar(self, x: int) -> int: ...
+    @override
+    # error: [invalid-overload] "`@override` decorator should be applied only to the overload implementation"
+    # error: [invalid-overload] "`@override` decorator should be applied only to the overload implementation"
+    # error: [invalid-explicit-override]
+    def bar(self, x: str | int) -> str | int:
+        return x
+
+    @overload
+    @override
+    def baz(self, x: str) -> str: ...
+    @overload
+    def baz(self, x: int) -> int: ...
+    # error: [invalid-overload] "`@override` decorator should be applied only to the overload implementation"
+    # error: [invalid-explicit-override]
+    def baz(self, x: str | int) -> str | int:
+        return x
+```
+
+In a stub file, `@override` should always be applied to the first overload. Even if it isn't, we
+always emit `invalid-explicit-override` diagnostics on the first overload.
+
+`module.pyi`:
+
+```pyi
+from typing_extensions import override, overload
+
+class Spam:
+    @overload
+    def foo(self, x: str) -> str: ...  # error: [invalid-explicit-override]
+    @overload
+    @override
+    # error: [invalid-overload]  "`@override` decorator should be applied only to the first overload"
+    def foo(self, x: int) -> int: ...
+
+    @overload
+    @override
+    def bar(self, x: str) -> str: ...  # error: [invalid-explicit-override]
+    @overload
+    @override
+    # error: [invalid-overload]  "`@override` decorator should be applied only to the first overload"
+    def bar(self, x: int) -> int: ...
+
+    @overload
+    @override
+    def baz(self, x: str) -> str: ...  # error: [invalid-explicit-override]
+    @overload
+    def baz(self, x: int) -> int: ...
+```
+
+## Classes inheriting from `Any`
+
+```py
+from typing_extensions import Any, override
+from does_not_exist import SomethingUnknown  # error: [unresolved-import]
+
+class Parent1(Any): ...
+class Parent2(SomethingUnknown): ...
+
+class Child1(Parent1):
+    @override
+    def bar(self): ...  # fine
+
+class Child2(Parent2):
+    @override
+    def bar(self): ...  # fine
+```
+
+## Override of a synthesized method
+
+```pyi
+from typing_extensions import NamedTuple, TypedDict, override, Any, Self
+from dataclasses import dataclass
+
+@dataclass(order=True)
+class ParentDataclass:
+    x: int
+
+class Child(ParentDataclass):
+    @override
+    def __lt__(self, other: ParentDataclass) -> bool: ...  # fine
+
+class MyNamedTuple(NamedTuple):
+    x: int
+
+    @override
+    # TODO: this raises an exception at runtime (which we should emit a diagnostic for).
+    # It shouldn't be an `invalid-explicit-override` diagnostic, however.
+    def _asdict(self, /) -> dict[str, Any]: ...
+
+class MyNamedTupleParent(NamedTuple):
+    x: int
+
+class MyNamedTupleChild(MyNamedTupleParent):
+    @override
+    def _asdict(self, /) -> dict[str, Any]: ...  # fine
+
+class MyTypedDict(TypedDict):
+    x: int
+
+    @override
+    # TODO: it's invalid to define a method on a `TypedDict` class,
+    # so we should emit a diagnostic here.
+    # It shouldn't be an `invalid-explicit-override` diagnostic, however.
+    def copy(self) -> Self: ...
+
+class Grandparent(Any): ...
+
+class Parent(Grandparent, NamedTuple):  # error: [invalid-named-tuple]
+    x: int
+
+class Child(Parent):
+    @override
+    def foo(self): ...  # fine because `Any` is in the MRO
+```

crates/ty_python_semantic/resources/mdtest/pep613_type_aliases.md

@@ -144,17 +144,46 @@ def _(x: IntOrStr):
 ## Cyclic
 
 ```py
-from typing import TypeAlias
+from typing import TypeAlias, TypeVar, Union
+from types import UnionType
 
 RecursiveTuple: TypeAlias = tuple[int | "RecursiveTuple", str]
 
 def _(rec: RecursiveTuple):
+    # TODO should be `tuple[int | RecursiveTuple, str]`
     reveal_type(rec)  # revealed: tuple[Divergent, str]
 
 RecursiveHomogeneousTuple: TypeAlias = tuple[int | "RecursiveHomogeneousTuple", ...]
 
 def _(rec: RecursiveHomogeneousTuple):
+    # TODO should be `tuple[int | RecursiveHomogeneousTuple, ...]`
     reveal_type(rec)  # revealed: tuple[Divergent, ...]
+
+ClassInfo: TypeAlias = type | UnionType | tuple["ClassInfo", ...]
+reveal_type(ClassInfo)  # revealed: types.UnionType
+
+def my_isinstance(obj: object, classinfo: ClassInfo) -> bool:
+    # TODO should be `type | UnionType | tuple[ClassInfo, ...]`
+    reveal_type(classinfo)  # revealed: type | UnionType | tuple[Divergent, ...]
+    return isinstance(obj, classinfo)
+
+K = TypeVar("K")
+V = TypeVar("V")
+NestedDict: TypeAlias = dict[K, Union[V, "NestedDict[K, V]"]]
+
+def _(nested: NestedDict[str, int]):
+    # TODO should be `dict[str, int | NestedDict[str, int]]`
+    reveal_type(nested)  # revealed: @Todo(specialized generic alias in type expression)
+
+my_isinstance(1, int)
+my_isinstance(1, int | str)
+my_isinstance(1, (int, str))
+my_isinstance(1, (int, (str, float)))
+my_isinstance(1, (int, (str | float)))
+# error: [invalid-argument-type]
+my_isinstance(1, 1)
+# TODO should be an invalid-argument-type error
+my_isinstance(1, (int, (str, 1)))
 ```
 
 ## Conditionally imported on Python < 3.10

crates/ty_python_semantic/resources/mdtest/pep695_type_aliases.md

@@ -106,6 +106,29 @@ def _(flag: bool):
 ```py
 type ListOrSet[T] = list[T] | set[T]
 reveal_type(ListOrSet.__type_params__)  # revealed: tuple[TypeVar | ParamSpec | TypeVarTuple, ...]
+type Tuple1[T] = tuple[T]
+
+def _(cond: bool):
+    Generic = ListOrSet if cond else Tuple1
+
+    def _(x: Generic[int]):
+        reveal_type(x)  # revealed: list[int] | set[int] | tuple[int]
+
+try:
+    class Foo[T]:
+        x: T
+        def foo(self) -> T:
+            return self.x
+
+    ...
+except Exception:
+    class Foo[T]:
+        x: T
+        def foo(self) -> T:
+            return self.x
+
+def f(x: Foo[int]):
+    reveal_type(x.foo())  # revealed: int
 ```
 
 ## In unions and intersections
@@ -244,6 +267,47 @@ def f(x: IntOr, y: OrInt):
         reveal_type(x)  # revealed: Never
     if not isinstance(y, int):
         reveal_type(y)  # revealed: Never
+
+# error: [cyclic-type-alias-definition] "Cyclic definition of `Itself`"
+type Itself = Itself
+
+def foo(
+    # this is a very strange thing to do, but this is a regression test to ensure it doesn't panic
+    Itself: Itself,
+):
+    x: Itself
+    reveal_type(Itself)  # revealed: Divergent
+
+# A type alias defined with invalid recursion behaves as a dynamic type.
+foo(42)
+foo("hello")
+
+# error: [cyclic-type-alias-definition] "Cyclic definition of `A`"
+type A = B
+# error: [cyclic-type-alias-definition] "Cyclic definition of `B`"
+type B = A
+
+def bar(B: B):
+    x: B
+    reveal_type(B)  # revealed: Divergent
+
+# error: [cyclic-type-alias-definition] "Cyclic definition of `G`"
+type G[T] = G[T]
+# error: [cyclic-type-alias-definition] "Cyclic definition of `H`"
+type H[T] = I[T]
+# error: [cyclic-type-alias-definition] "Cyclic definition of `I`"
+type I[T] = H[T]
+
+# It's not possible to create an element of this type, but it's not an error for now
+type DirectRecursiveList[T] = list[DirectRecursiveList[T]]
+
+# TODO: this should probably be a cyclic-type-alias-definition error
+type Foo[T] = list[T] | Bar[T]
+type Bar[T] = int | Foo[T]
+
+def _(x: Bar[int]):
+    # TODO: should be `int | list[int]`
+    reveal_type(x)  # revealed: int | list[int] | Any
 ```
 
 ### With legacy generic
@@ -327,7 +391,7 @@ class C(P[T]):
     pass
 
 reveal_type(C[int]())  # revealed: C[int]
-reveal_type(C())  # revealed: C[Divergent]
+reveal_type(C())  # revealed: C[C[Divergent]]
 ```
 
 ### Union inside generic

crates/ty_python_semantic/resources/mdtest/protocols.md

@@ -2003,6 +2003,7 @@ python-version = "3.12"
 ```
 
 ```py
+from typing import final
 from typing_extensions import TypeVar, Self, Protocol
 from ty_extensions import is_equivalent_to, static_assert, is_assignable_to, is_subtype_of
 
@@ -2094,6 +2095,13 @@ class NominalReturningSelfNotGeneric:
     def g(self) -> "NominalReturningSelfNotGeneric":
         return self
 
+@final
+class Other: ...
+
+class NominalReturningOtherClass:
+    def g(self) -> Other:
+        raise NotImplementedError
+
 # TODO: should pass
 static_assert(is_equivalent_to(LegacyFunctionScoped, NewStyleFunctionScoped))  # error: [static-assert-error]
 
@@ -2112,8 +2120,7 @@ static_assert(not is_assignable_to(NominalLegacy, UsesSelf))
 static_assert(not is_assignable_to(NominalWithSelf, NewStyleFunctionScoped))
 static_assert(not is_assignable_to(NominalWithSelf, LegacyFunctionScoped))
 static_assert(is_assignable_to(NominalWithSelf, UsesSelf))
-# TODO: should pass
-static_assert(is_subtype_of(NominalWithSelf, UsesSelf))  # error: [static-assert-error]
+static_assert(is_subtype_of(NominalWithSelf, UsesSelf))
 
 # TODO: these should pass
 static_assert(not is_assignable_to(NominalNotGeneric, NewStyleFunctionScoped))  # error: [static-assert-error]
@@ -2126,6 +2133,8 @@ static_assert(not is_assignable_to(NominalReturningSelfNotGeneric, LegacyFunctio
 # TODO: should pass
 static_assert(not is_assignable_to(NominalReturningSelfNotGeneric, UsesSelf))  # error: [static-assert-error]
 
+static_assert(not is_assignable_to(NominalReturningOtherClass, UsesSelf))
+
 # These test cases are taken from the typing conformance suite:
 class ShapeProtocolImplicitSelf(Protocol):
     def set_scale(self, scale: float) -> Self: ...

crates/ty_python_semantic/resources/mdtest/regression/1377_iteration_count_mismatch.md

@@ -2,10 +2,7 @@
 
 Regression test for <https://github.com/astral-sh/ty/issues/1377>.
 
-The code is an excerpt from <https://github.com/Gobot1234/steam.py> that is minimal enough to
-trigger the iteration count mismatch bug in Salsa.
-
-<!-- expect-panic: execute: too many cycle iterations -->
+The code is an excerpt from <https://github.com/Gobot1234/steam.py>.
 
 ```toml
 [environment]

crates/ty_python_semantic/resources/mdtest/snapshots/attributes.md_-_Attributes_-_Attributes_of_standa…_(49ba2c9016d64653).snap

@@ -32,7 +32,8 @@ error[unresolved-attribute]: Module `datetime` has no member `UTC`
 5 | # error: [unresolved-attribute]
 6 | reveal_type(datetime.fakenotreal)  # revealed: Unknown
   |
-info: Python 3.10 was assumed when accessing `UTC` because it was specified on the command line
+info: The member may be available on other Python versions or platforms
+info: Python 3.10 was assumed when resolving the `UTC` attribute because it was specified on the command line
 info: rule `unresolved-attribute` is enabled by default
 
 ```

crates/ty_python_semantic/resources/mdtest/snapshots/attributes.md_-_Attributes_-_Unimported_submodule…_(2b6da09ed380b2).snap

@@ -30,39 +30,39 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/attributes.md
 1 | import foo
 2 | import baz
 3 | 
-4 | # error: [unresolved-attribute]
-5 | reveal_type(foo.bar)  # revealed: Unknown
-6 | # error: [unresolved-attribute]
-7 | reveal_type(baz.bar)  # revealed: Unknown
+4 | # error: [possibly-missing-attribute]
+5 | reveal_type(foo.bar)  # revealed: <module 'foo.bar'>
+6 | # error: [possibly-missing-attribute]
+7 | reveal_type(baz.bar)  # revealed: <module 'baz.bar'>
 ```
 
 # Diagnostics
 
 ```
-error[unresolved-attribute]: Submodule `bar` may not be available as an attribute on module `foo`
+warning[possibly-missing-attribute]: Submodule `bar` may not be available as an attribute on module `foo`
  --> src/main.py:5:13
   |
-4 | # error: [unresolved-attribute]
-5 | reveal_type(foo.bar)  # revealed: Unknown
+4 | # error: [possibly-missing-attribute]
+5 | reveal_type(foo.bar)  # revealed: <module 'foo.bar'>
   |             ^^^^^^^
-6 | # error: [unresolved-attribute]
-7 | reveal_type(baz.bar)  # revealed: Unknown
+6 | # error: [possibly-missing-attribute]
+7 | reveal_type(baz.bar)  # revealed: <module 'baz.bar'>
   |
 help: Consider explicitly importing `foo.bar`
-info: rule `unresolved-attribute` is enabled by default
+info: rule `possibly-missing-attribute` is enabled by default
 
 ```
 
 ```
-error[unresolved-attribute]: Submodule `bar` may not be available as an attribute on module `baz`
+warning[possibly-missing-attribute]: Submodule `bar` may not be available as an attribute on module `baz`
  --> src/main.py:7:13
   |
-5 | reveal_type(foo.bar)  # revealed: Unknown
-6 | # error: [unresolved-attribute]
-7 | reveal_type(baz.bar)  # revealed: Unknown
+5 | reveal_type(foo.bar)  # revealed: <module 'foo.bar'>
+6 | # error: [possibly-missing-attribute]
+7 | reveal_type(baz.bar)  # revealed: <module 'baz.bar'>
   |             ^^^^^^^
   |
 help: Consider explicitly importing `baz.bar`
-info: rule `unresolved-attribute` is enabled by default
+info: rule `possibly-missing-attribute` is enabled by default
 
 ```

crates/ty_python_semantic/resources/mdtest/snapshots/invalid.md_-_Tests_for_invalid_ty…_-_Diagnostics_for_comm…_-_Module-literal_used_…_(652fec4fd4a6c63a).snap

@@ -34,29 +34,27 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/annotations/invalid.md
 # Diagnostics
 
 ```
-error[invalid-type-form]: Variable of type `<module 'datetime'>` is not allowed in a type expression
+error[invalid-type-form]: Module `datetime` is not valid in a type expression
  --> src/foo.py:3:10
   |
 1 | import datetime
 2 |
 3 | def f(x: datetime): ...  # error: [invalid-type-form]
-  |          ^^^^^^^^
+  |          ^^^^^^^^ Did you mean to use the module's member `datetime.datetime`?
   |
-info: Did you mean to use the module's member `datetime.datetime` instead?
 info: rule `invalid-type-form` is enabled by default
 
 ```
 
 ```
-error[invalid-type-form]: Variable of type `<module 'PIL.Image'>` is not allowed in a type expression
+error[invalid-type-form]: Module `PIL.Image` is not valid in a type expression
  --> src/bar.py:3:10
   |
 1 | from PIL import Image
 2 |
 3 | def g(x: Image): ...  # error: [invalid-type-form]
-  |          ^^^^^
+  |          ^^^^^ Did you mean to use the module's member `Image.Image`?
   |
-info: Did you mean to use the module's member `Image.Image` instead?
 info: rule `invalid-type-form` is enabled by default
 
 ```

crates/ty_python_semantic/resources/mdtest/snapshots/invalid_assignment.m…_-_Invalid_assignment_d…_-_Multiple_targets_(e20ddfd7a91affb0).snap

@@ -23,13 +23,13 @@ mdtest path: crates/ty_python_semantic/resources/mdtest/diagnostics/invalid_assi
 # Diagnostics
 
 ```
-error[invalid-assignment]: Object of type `tuple[Literal["a"], Literal["b"]]` is not assignable to `int`
+error[invalid-assignment]: Object of type `Literal["a"]` is not assignable to `int`
  --> src/mdtest_snippet.py:4:1
   |
 2 | y: str
 3 |
 4 | x, y = ("a", "b")  # error: [invalid-assignment]
-  | -      ^^^^^^^^^^ Incompatible value of type `tuple[Literal["a"], Literal["b"]]`
+  | -      ^^^^^^^^^^ Incompatible value of type `Literal["a"]`
   | |
   | Declared type `int`
 5 |
@@ -40,13 +40,13 @@ info: rule `invalid-assignment` is enabled by default
 ```
 
 ```
-error[invalid-assignment]: Object of type `tuple[Literal[0], Literal[0]]` is not assignable to `str`
+error[invalid-assignment]: Object of type `Literal[0]` is not assignable to `str`
  --> src/mdtest_snippet.py:6:4
   |
 4 | x, y = ("a", "b")  # error: [invalid-assignment]
 5 |
 6 | x, y = (0, 0)  # error: [invalid-assignment]
-  |    -   ^^^^^^ Incompatible value of type `tuple[Literal[0], Literal[0]]`
+  |    -   ^^^^^^ Incompatible value of type `Literal[0]`
   |    |
   |    Declared type `str`
   |

crates/ty_python_semantic/resources/mdtest/snapshots/liskov.md_-_The_Liskov_Substitut…_-_Staticmethods_and_cl…_(49e28aae6fdd1291).snap

@@ -0,0 +1,220 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: liskov.md - The Liskov Substitution Principle - Staticmethods and classmethods
+mdtest path: crates/ty_python_semantic/resources/mdtest/liskov.md
+---
+
+# Python source files
+
+## mdtest_snippet.pyi
+
+```
+ 1 | class Parent:
+ 2 |     def instance_method(self, x: int) -> int: ...
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+ 7 | 
+ 8 | class BadChild1(Parent):
+ 9 |     @staticmethod
+10 |     def instance_method(self, x: int) -> int: ...  # error: [invalid-method-override]
+11 |     # TODO: we should emit `invalid-method-override` here.
+12 |     # Although the method has the same signature as `Parent.class_method`
+13 |     # when accessed on instances, it does not have the same signature as
+14 |     # `Parent.class_method` when accessed on the class object itself
+15 |     def class_method(cls, x: int) -> int: ...
+16 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+17 | 
+18 | class BadChild2(Parent):
+19 |     # TODO: we should emit `invalid-method-override` here.
+20 |     # Although the method has the same signature as `Parent.class_method`
+21 |     # when accessed on instances, it does not have the same signature as
+22 |     # `Parent.class_method` when accessed on the class object itself.
+23 |     #
+24 |     # Note that whereas `BadChild1.class_method` is reported as a Liskov violation by
+25 |     # mypy, pyright and pyrefly, pyright is the only one of those three to report a
+26 |     # Liskov violation on this method as of 2025-11-23.
+27 |     @classmethod
+28 |     def instance_method(self, x: int) -> int: ...
+29 |     @staticmethod
+30 |     def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+31 |     @classmethod
+32 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+33 | 
+34 | class BadChild3(Parent):
+35 |     @classmethod
+36 |     def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+37 |     @staticmethod
+38 |     def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+39 | 
+40 | class GoodChild1(Parent):
+41 |     @classmethod
+42 |     def class_method(cls, x: int) -> int: ...
+43 |     @staticmethod
+44 |     def static_method(x: int) -> int: ...
+45 | 
+46 | class GoodChild2(Parent):
+47 |     @classmethod
+48 |     def class_method(cls, x: object) -> bool: ...
+49 |     @staticmethod
+50 |     def static_method(x: object) -> bool: ...
+```
+
+# Diagnostics
+
+```
+error[invalid-method-override]: Invalid override of method `instance_method`
+  --> src/mdtest_snippet.pyi:10:9
+   |
+ 8 | class BadChild1(Parent):
+ 9 |     @staticmethod
+10 |     def instance_method(self, x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.instance_method`
+11 |     # TODO: we should emit `invalid-method-override` here.
+12 |     # Although the method has the same signature as `Parent.class_method`
+   |
+  ::: src/mdtest_snippet.pyi:2:9
+   |
+ 1 | class Parent:
+ 2 |     def instance_method(self, x: int) -> int: ...
+   |         ------------------------------------ `Parent.instance_method` defined here
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+   |
+info: `BadChild1.instance_method` is a staticmethod but `Parent.instance_method` is an instance method
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `static_method`
+  --> src/mdtest_snippet.pyi:16:9
+   |
+14 |     # `Parent.class_method` when accessed on the class object itself
+15 |     def class_method(cls, x: int) -> int: ...
+16 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.static_method`
+17 |
+18 | class BadChild2(Parent):
+   |
+  ::: src/mdtest_snippet.pyi:6:9
+   |
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |         ---------------------------- `Parent.static_method` defined here
+ 7 |
+ 8 | class BadChild1(Parent):
+   |
+info: `BadChild1.static_method` is an instance method but `Parent.static_method` is a staticmethod
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `class_method`
+  --> src/mdtest_snippet.pyi:30:9
+   |
+28 |     def instance_method(self, x: int) -> int: ...
+29 |     @staticmethod
+30 |     def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.class_method`
+31 |     @classmethod
+32 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+   |
+  ::: src/mdtest_snippet.pyi:4:9
+   |
+ 2 |     def instance_method(self, x: int) -> int: ...
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+   |         -------------------------------- `Parent.class_method` defined here
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |
+info: `BadChild2.class_method` is a staticmethod but `Parent.class_method` is a classmethod
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `static_method`
+  --> src/mdtest_snippet.pyi:32:9
+   |
+30 |     def class_method(cls, x: int) -> int: ...  # error: [invalid-method-override]
+31 |     @classmethod
+32 |     def static_method(x: int) -> int: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.static_method`
+33 |
+34 | class BadChild3(Parent):
+   |
+  ::: src/mdtest_snippet.pyi:6:9
+   |
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |         ---------------------------- `Parent.static_method` defined here
+ 7 |
+ 8 | class BadChild1(Parent):
+   |
+info: `BadChild2.static_method` is a classmethod but `Parent.static_method` is a staticmethod
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `class_method`
+  --> src/mdtest_snippet.pyi:36:9
+   |
+34 | class BadChild3(Parent):
+35 |     @classmethod
+36 |     def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.class_method`
+37 |     @staticmethod
+38 |     def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+   |
+  ::: src/mdtest_snippet.pyi:4:9
+   |
+ 2 |     def instance_method(self, x: int) -> int: ...
+ 3 |     @classmethod
+ 4 |     def class_method(cls, x: int) -> int: ...
+   |         -------------------------------- `Parent.class_method` defined here
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```
+
+```
+error[invalid-method-override]: Invalid override of method `static_method`
+  --> src/mdtest_snippet.pyi:38:9
+   |
+36 |     def class_method(cls, x: bool) -> object: ...  # error: [invalid-method-override]
+37 |     @staticmethod
+38 |     def static_method(x: bool) -> object: ...  # error: [invalid-method-override]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Definition is incompatible with `Parent.static_method`
+39 |
+40 | class GoodChild1(Parent):
+   |
+  ::: src/mdtest_snippet.pyi:6:9
+   |
+ 4 |     def class_method(cls, x: int) -> int: ...
+ 5 |     @staticmethod
+ 6 |     def static_method(x: int) -> int: ...
+   |         ---------------------------- `Parent.static_method` defined here
+ 7 |
+ 8 | class BadChild1(Parent):
+   |
+info: This violates the Liskov Substitution Principle
+info: rule `invalid-method-override` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/literal_string.md_-_`LiteralString`_-_Usages_-_Parameterized_(ec84ce49ea235791).snap

@@ -0,0 +1,52 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: literal_string.md - `LiteralString` - Usages - Parameterized
+mdtest path: crates/ty_python_semantic/resources/mdtest/annotations/literal_string.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from typing_extensions import LiteralString
+2 | 
+3 | # error: [invalid-type-form]
+4 | a: LiteralString[str]
+5 | 
+6 | # error: [invalid-type-form]
+7 | b: LiteralString["foo"]
+```
+
+# Diagnostics
+
+```
+error[invalid-type-form]: `LiteralString` expects no type parameter
+ --> src/mdtest_snippet.py:4:4
+  |
+3 | # error: [invalid-type-form]
+4 | a: LiteralString[str]
+  |    ^^^^^^^^^^^^^^^^^^
+5 |
+6 | # error: [invalid-type-form]
+  |
+info: rule `invalid-type-form` is enabled by default
+
+```
+
+```
+error[invalid-type-form]: `LiteralString` expects no type parameter
+ --> src/mdtest_snippet.py:7:4
+  |
+6 | # error: [invalid-type-form]
+7 | b: LiteralString["foo"]
+  |    -------------^^^^^^^
+  |    |
+  |    Did you mean `Literal`?
+  |
+info: rule `invalid-type-form` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/mro.md_-_Method_Resolution_Or…_-_`__bases__`_lists_wi…_(ea7ebc83ec359b54).snap

@@ -312,6 +312,15 @@ info[unused-ignore-comment]: Unused blanket `type: ignore` directive
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 73 | ): ...
    |
+help: Remove the unused suppression comment
+69 | class D(
+70 |     A,
+71 |     # error: [unused-ignore-comment]
+   -     A,  # type: ignore[duplicate-base]
+72 +     A,
+73 | ): ...
+74 | 
+75 | # error: [duplicate-base]
 
 ```
 
@@ -356,5 +365,13 @@ info[unused-ignore-comment]: Unused blanket `type: ignore` directive
 82 |
 83 | # fmt: on
    |
+help: Remove the unused suppression comment
+78 |     A
+79 | ):
+80 |     # error: [unused-ignore-comment]
+   -     x: int  # type: ignore[duplicate-base]
+81 +     x: int
+82 | 
+83 | # fmt: on
 
 ```

crates/ty_python_semantic/resources/mdtest/snapshots/override.md_-_`typing.override`_-_Basics_(b7c220f8171f11f0).snap

@@ -0,0 +1,293 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: override.md - `typing.override` - Basics
+mdtest path: crates/ty_python_semantic/resources/mdtest/override.md
+---
+
+# Python source files
+
+## mdtest_snippet.pyi
+
+```
+  1 | from typing_extensions import override, Callable, TypeVar
+  2 | 
+  3 | def lossy_decorator(fn: Callable) -> Callable: ...
+  4 | 
+  5 | class A:
+  6 |     @override
+  7 |     def __repr__(self): ...  # fine: overrides `object.__repr__`
+  8 | 
+  9 | class Parent:
+ 10 |     def foo(self): ...
+ 11 |     @property
+ 12 |     def my_property1(self) -> int: ...
+ 13 |     @property
+ 14 |     def my_property2(self) -> int: ...
+ 15 |     baz = None
+ 16 |     @classmethod
+ 17 |     def class_method1(cls) -> int: ...
+ 18 |     @staticmethod
+ 19 |     def static_method1() -> int: ...
+ 20 |     @classmethod
+ 21 |     def class_method2(cls) -> int: ...
+ 22 |     @staticmethod
+ 23 |     def static_method2() -> int: ...
+ 24 |     @lossy_decorator
+ 25 |     def decorated_1(self): ...
+ 26 |     @lossy_decorator
+ 27 |     def decorated_2(self): ...
+ 28 |     @lossy_decorator
+ 29 |     def decorated_3(self): ...
+ 30 | 
+ 31 | class Child(Parent):
+ 32 |     @override
+ 33 |     def foo(self): ...  # fine: overrides `Parent.foo`
+ 34 |     @property
+ 35 |     @override
+ 36 |     def my_property1(self) -> int: ...  # fine: overrides `Parent.my_property1`
+ 37 |     @override
+ 38 |     @property
+ 39 |     def my_property2(self) -> int: ...  # fine: overrides `Parent.my_property2`
+ 40 |     @override
+ 41 |     def baz(self): ...  # fine: overrides `Parent.baz`
+ 42 |     @classmethod
+ 43 |     @override
+ 44 |     def class_method1(cls) -> int: ...  # fine: overrides `Parent.class_method1`
+ 45 |     @staticmethod
+ 46 |     @override
+ 47 |     def static_method1() -> int: ...  # fine: overrides `Parent.static_method1`
+ 48 |     @override
+ 49 |     @classmethod
+ 50 |     def class_method2(cls) -> int: ...  # fine: overrides `Parent.class_method2`
+ 51 |     @override
+ 52 |     @staticmethod
+ 53 |     def static_method2() -> int: ...  # fine: overrides `Parent.static_method2`
+ 54 |     @override
+ 55 |     def decorated_1(self): ...  # fine: overrides `Parent.decorated_1`
+ 56 |     @override
+ 57 |     @lossy_decorator
+ 58 |     def decorated_2(self): ...  # fine: overrides `Parent.decorated_2`
+ 59 |     @lossy_decorator
+ 60 |     @override
+ 61 |     def decorated_3(self): ...  # fine: overrides `Parent.decorated_3`
+ 62 | 
+ 63 | class OtherChild(Parent): ...
+ 64 | 
+ 65 | class Grandchild(OtherChild):
+ 66 |     @override
+ 67 |     def foo(self): ...  # fine: overrides `Parent.foo`
+ 68 |     @override
+ 69 |     @property
+ 70 |     def bar(self) -> int: ...  # fine: overrides `Parent.bar`
+ 71 |     @override
+ 72 |     def baz(self): ...  # fine: overrides `Parent.baz`
+ 73 |     @classmethod
+ 74 |     @override
+ 75 |     def class_method1(cls) -> int: ...  # fine: overrides `Parent.class_method1`
+ 76 |     @staticmethod
+ 77 |     @override
+ 78 |     def static_method1() -> int: ...  # fine: overrides `Parent.static_method1`
+ 79 |     @override
+ 80 |     @classmethod
+ 81 |     def class_method2(cls) -> int: ...  # fine: overrides `Parent.class_method2`
+ 82 |     @override
+ 83 |     @staticmethod
+ 84 |     def static_method2() -> int: ...  # fine: overrides `Parent.static_method2`
+ 85 |     @override
+ 86 |     def decorated_1(self): ...  # fine: overrides `Parent.decorated_1`
+ 87 |     @override
+ 88 |     @lossy_decorator
+ 89 |     def decorated_2(self): ...  # fine: overrides `Parent.decorated_2`
+ 90 |     @lossy_decorator
+ 91 |     @override
+ 92 |     def decorated_3(self): ...  # fine: overrides `Parent.decorated_3`
+ 93 | 
+ 94 | class Invalid:
+ 95 |     @override
+ 96 |     def ___reprrr__(self): ...  # error: [invalid-explicit-override]
+ 97 |     @override
+ 98 |     @classmethod
+ 99 |     def foo(self): ...  # error: [invalid-explicit-override]
+100 |     @classmethod
+101 |     @override
+102 |     def bar(self): ...  # error: [invalid-explicit-override]
+103 |     @staticmethod
+104 |     @override
+105 |     def baz(): ...  # error: [invalid-explicit-override]
+106 |     @override
+107 |     @staticmethod
+108 |     def eggs(): ...  # error: [invalid-explicit-override]
+109 |     @property
+110 |     @override
+111 |     def bad_property1(self) -> int: ...  # TODO: should emit `invalid-explicit-override` here
+112 |     @override
+113 |     @property
+114 |     def bad_property2(self) -> int: ...  # TODO: should emit `invalid-explicit-override` here
+115 |     @lossy_decorator
+116 |     @override
+117 |     def lossy(self): ...  # TODO: should emit `invalid-explicit-override` here
+118 |     @override
+119 |     @lossy_decorator
+120 |     def lossy2(self): ...  # TODO: should emit `invalid-explicit-override` here
+121 | 
+122 | # TODO: all overrides in this class should cause us to emit *Liskov* violations,
+123 | # but not `@override` violations
+124 | class LiskovViolatingButNotOverrideViolating(Parent):
+125 |     @override
+126 |     @property
+127 |     def foo(self) -> int: ...
+128 |     @override
+129 |     def my_property1(self) -> int: ...
+130 |     @staticmethod
+131 |     @override
+132 |     def class_method1() -> int: ...
+133 |     @classmethod
+134 |     @override
+135 |     def static_method1(cls) -> int: ...
+136 | 
+137 | # Diagnostic edge case: `override` is very far away from the method definition in the source code:
+138 | 
+139 | T = TypeVar("T")
+140 | 
+141 | def identity(x: T) -> T: ...
+142 | 
+143 | class Foo:
+144 |     @override
+145 |     @identity
+146 |     @identity
+147 |     @identity
+148 |     @identity
+149 |     @identity
+150 |     @identity
+151 |     @identity
+152 |     @identity
+153 |     @identity
+154 |     @identity
+155 |     @identity
+156 |     @identity
+157 |     @identity
+158 |     @identity
+159 |     @identity
+160 |     @identity
+161 |     @identity
+162 |     @identity
+163 |     def bar(self): ...  # error: [invalid-explicit-override]
+```
+
+# Diagnostics
+
+```
+error[invalid-explicit-override]: Method `___reprrr__` is decorated with `@override` but does not override anything
+  --> src/mdtest_snippet.pyi:95:5
+   |
+94 | class Invalid:
+95 |     @override
+   |     ---------
+96 |     def ___reprrr__(self): ...  # error: [invalid-explicit-override]
+   |         ^^^^^^^^^^^
+97 |     @override
+98 |     @classmethod
+   |
+info: No `___reprrr__` definitions were found on any superclasses of `Invalid`
+info: rule `invalid-explicit-override` is enabled by default
+
+```
+
+```
+error[invalid-explicit-override]: Method `foo` is decorated with `@override` but does not override anything
+   --> src/mdtest_snippet.pyi:97:5
+    |
+ 95 |     @override
+ 96 |     def ___reprrr__(self): ...  # error: [invalid-explicit-override]
+ 97 |     @override
+    |     ---------
+ 98 |     @classmethod
+ 99 |     def foo(self): ...  # error: [invalid-explicit-override]
+    |         ^^^
+100 |     @classmethod
+101 |     @override
+    |
+info: No `foo` definitions were found on any superclasses of `Invalid`
+info: rule `invalid-explicit-override` is enabled by default
+
+```
+
+```
+error[invalid-explicit-override]: Method `bar` is decorated with `@override` but does not override anything
+   --> src/mdtest_snippet.pyi:101:5
+    |
+ 99 |     def foo(self): ...  # error: [invalid-explicit-override]
+100 |     @classmethod
+101 |     @override
+    |     ---------
+102 |     def bar(self): ...  # error: [invalid-explicit-override]
+    |         ^^^
+103 |     @staticmethod
+104 |     @override
+    |
+info: No `bar` definitions were found on any superclasses of `Invalid`
+info: rule `invalid-explicit-override` is enabled by default
+
+```
+
+```
+error[invalid-explicit-override]: Method `baz` is decorated with `@override` but does not override anything
+   --> src/mdtest_snippet.pyi:104:5
+    |
+102 |     def bar(self): ...  # error: [invalid-explicit-override]
+103 |     @staticmethod
+104 |     @override
+    |     ---------
+105 |     def baz(): ...  # error: [invalid-explicit-override]
+    |         ^^^
+106 |     @override
+107 |     @staticmethod
+    |
+info: No `baz` definitions were found on any superclasses of `Invalid`
+info: rule `invalid-explicit-override` is enabled by default
+
+```
+
+```
+error[invalid-explicit-override]: Method `eggs` is decorated with `@override` but does not override anything
+   --> src/mdtest_snippet.pyi:106:5
+    |
+104 |     @override
+105 |     def baz(): ...  # error: [invalid-explicit-override]
+106 |     @override
+    |     ---------
+107 |     @staticmethod
+108 |     def eggs(): ...  # error: [invalid-explicit-override]
+    |         ^^^^
+109 |     @property
+110 |     @override
+    |
+info: No `eggs` definitions were found on any superclasses of `Invalid`
+info: rule `invalid-explicit-override` is enabled by default
+
+```
+
+```
+error[invalid-explicit-override]: Method `bar` is decorated with `@override` but does not override anything
+   --> src/mdtest_snippet.pyi:163:9
+    |
+161 |     @identity
+162 |     @identity
+163 |     def bar(self): ...  # error: [invalid-explicit-override]
+    |         ^^^
+    |
+   ::: src/mdtest_snippet.pyi:144:5
+    |
+143 | class Foo:
+144 |     @override
+    |     ---------
+145 |     @identity
+146 |     @identity
+    |
+info: No `bar` definitions were found on any superclasses of `Foo`
+info: rule `invalid-explicit-override` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/ty_ignore.md_-_Suppressing_errors_w…_-_Multiple_unused_comm…_(7cbe4a1d9893a05).snap

@@ -0,0 +1,109 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: ty_ignore.md - Suppressing errors with `ty: ignore` - Multiple unused comments
+mdtest path: crates/ty_python_semantic/resources/mdtest/suppressions/ty_ignore.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive"
+2 | a = 10 / 2  # ty: ignore[division-by-zero, unresolved-reference]
+3 | 
+4 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
+5 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+6 | a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero, unresolved-reference]
+7 | 
+8 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+9 | a = 10 / 0  # ty: ignore[invalid-assignment, unresolved-reference, division-by-zero]
+```
+
+# Diagnostics
+
+```
+info[unused-ignore-comment]: Unused `ty: ignore` directive
+ --> src/mdtest_snippet.py:2:13
+  |
+1 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive"
+2 | a = 10 / 2  # ty: ignore[division-by-zero, unresolved-reference]
+  |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+3 |
+4 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
+  |
+help: Remove the unused suppression comment
+1 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive"
+  - a = 10 / 2  # ty: ignore[division-by-zero, unresolved-reference]
+2 + a = 10 / 2
+3 | 
+4 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
+5 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+
+```
+
+```
+info[unused-ignore-comment]: Unused `ty: ignore` directive: 'invalid-assignment'
+ --> src/mdtest_snippet.py:6:26
+  |
+4 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
+5 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+6 | a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero, unresolved-reference]
+  |                          ^^^^^^^^^^^^^^^^^^
+7 |
+8 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+  |
+help: Remove the unused suppression code
+3 | 
+4 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
+5 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+  - a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero, unresolved-reference]
+6 + a = 10 / 0  # ty: ignore[division-by-zero, unresolved-reference]
+7 | 
+8 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+9 | a = 10 / 0  # ty: ignore[invalid-assignment, unresolved-reference, division-by-zero]
+
+```
+
+```
+info[unused-ignore-comment]: Unused `ty: ignore` directive: 'unresolved-reference'
+ --> src/mdtest_snippet.py:6:64
+  |
+4 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
+5 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+6 | a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero, unresolved-reference]
+  |                                                                ^^^^^^^^^^^^^^^^^^^^
+7 |
+8 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+  |
+help: Remove the unused suppression code
+3 | 
+4 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
+5 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+  - a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero, unresolved-reference]
+6 + a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero]
+7 | 
+8 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+9 | a = 10 / 0  # ty: ignore[invalid-assignment, unresolved-reference, division-by-zero]
+
+```
+
+```
+info[unused-ignore-comment]: Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'
+ --> src/mdtest_snippet.py:9:26
+  |
+8 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+9 | a = 10 / 0  # ty: ignore[invalid-assignment, unresolved-reference, division-by-zero]
+  |                          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+  |
+help: Remove the unused suppression codes
+6 | a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero, unresolved-reference]
+7 | 
+8 | # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+  - a = 10 / 0  # ty: ignore[invalid-assignment, unresolved-reference, division-by-zero]
+9 + a = 10 / 0  # ty: ignore[division-by-zero]
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/type_ignore.md_-_Suppressing_errors_w…_-_Nested_comments_(6e4dc67270e388d2).snap

@@ -0,0 +1,72 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: type_ignore.md - Suppressing errors with `type: ignore` - Nested comments
+mdtest path: crates/ty_python_semantic/resources/mdtest/suppressions/type_ignore.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+ 1 | # fmt: off
+ 2 | a = test /
+ 3 |   + 2  # fmt: skip # type: ignore
+ 4 | 
+ 5 | a = test /
+ 6 |   + 2  # type: ignore # fmt: skip
+ 7 | 
+ 8 | a = (3
+ 9 |   # error: [unused-ignore-comment]
+10 |   + 2)  # ty:ignore[division-by-zero] # fmt: skip
+11 | 
+12 | a = (3
+13 |   # error: [unused-ignore-comment]
+14 |   + 2)  # fmt: skip # ty:ignore[division-by-zero]
+```
+
+# Diagnostics
+
+```
+info[unused-ignore-comment]: Unused `ty: ignore` directive
+  --> src/mdtest_snippet.py:10:9
+   |
+ 8 | a = (3
+ 9 |   # error: [unused-ignore-comment]
+10 |   + 2)  # ty:ignore[division-by-zero] # fmt: skip
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+11 |
+12 | a = (3
+   |
+help: Remove the unused suppression comment
+7  | 
+8  | a = (3
+9  |   # error: [unused-ignore-comment]
+   -   + 2)  # ty:ignore[division-by-zero] # fmt: skip
+10 +   + 2)  # fmt: skip
+11 | 
+12 | a = (3
+13 |   # error: [unused-ignore-comment]
+
+```
+
+```
+info[unused-ignore-comment]: Unused `ty: ignore` directive
+  --> src/mdtest_snippet.py:14:21
+   |
+12 | a = (3
+13 |   # error: [unused-ignore-comment]
+14 |   + 2)  # fmt: skip # ty:ignore[division-by-zero]
+   |                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   |
+help: Remove the unused suppression comment
+11 | 
+12 | a = (3
+13 |   # error: [unused-ignore-comment]
+   -   + 2)  # fmt: skip # ty:ignore[division-by-zero]
+14 +   + 2)  # fmt: skip 
+
+```

crates/ty_python_semantic/resources/mdtest/snapshots/typed_dict.md_-_`TypedDict`_-_Error_cases_-_`typing.TypedDict`_i…_(9df67eb93e3df341).snap

@@ -0,0 +1,34 @@
+---
+source: crates/ty_test/src/lib.rs
+expression: snapshot
+---
+---
+mdtest name: typed_dict.md - `TypedDict` - Error cases - `typing.TypedDict` is not allowed in type expressions
+mdtest path: crates/ty_python_semantic/resources/mdtest/typed_dict.md
+---
+
+# Python source files
+
+## mdtest_snippet.py
+
+```
+1 | from typing import TypedDict
+2 | 
+3 | # error: [invalid-type-form] "The special form `typing.TypedDict` is not allowed in type expressions"
+4 | x: TypedDict = {"name": "Alice"}
+```
+
+# Diagnostics
+
+```
+error[invalid-type-form]: The special form `typing.TypedDict` is not allowed in type expressions
+ --> src/mdtest_snippet.py:4:4
+  |
+3 | # error: [invalid-type-form] "The special form `typing.TypedDict` is not allowed in type expressions"
+4 | x: TypedDict = {"name": "Alice"}
+  |    ^^^^^^^^^
+  |
+help: You might have meant to use a concrete TypedDict or `collections.abc.Mapping[str, object]`
+info: rule `invalid-type-form` is enabled by default
+
+```

crates/ty_python_semantic/resources/mdtest/suppressions/no_type_check.md

@@ -117,6 +117,6 @@ from typing import no_type_check
 
 @no_type_check
 def test():
-    # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+    # error: [unused-ignore-comment] "Unused `ty: ignore` directive"
     return x + 5  # ty: ignore[unresolved-reference]
 ```

crates/ty_python_semantic/resources/mdtest/suppressions/ty_ignore.md

@@ -18,7 +18,7 @@ a = 4 + test  # ty: ignore[unresolved-reference]
 
 ```py
 test = 10
-# error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'possibly-unresolved-reference'"
+# error: [unused-ignore-comment] "Unused `ty: ignore` directive"
 a = test + 3  # ty: ignore[possibly-unresolved-reference]
 ```
 
@@ -26,7 +26,7 @@ a = test + 3  # ty: ignore[possibly-unresolved-reference]
 
 ```py
 # error: [unresolved-reference]
-# error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'possibly-unresolved-reference'"
+# error: [unused-ignore-comment] "Unused `ty: ignore` directive"
 a = test + 3  # ty: ignore[possibly-unresolved-reference]
 ```
 
@@ -50,17 +50,20 @@ a = 10 / 0  # ty: ignore[division-by-zero, unused-ignore-comment]
 
 ## Multiple unused comments
 
-Today, ty emits a diagnostic for every unused code. We might want to group the codes by comment at
-some point in the future.
+ty groups unused codes that are next to each other.
+
+<!-- snapshot-diagnostics -->
 
 ```py
-# error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'division-by-zero'"
-# error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
+# error: [unused-ignore-comment] "Unused `ty: ignore` directive"
 a = 10 / 2  # ty: ignore[division-by-zero, unresolved-reference]
 
 # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment'"
 # error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'unresolved-reference'"
 a = 10 / 0  # ty: ignore[invalid-assignment, division-by-zero, unresolved-reference]
+
+# error: [unused-ignore-comment] "Unused `ty: ignore` directive: 'invalid-assignment', 'unresolved-reference'"
+a = 10 / 0  # ty: ignore[invalid-assignment, unresolved-reference, division-by-zero]
 ```
 
 ## Multiple suppressions

crates/ty_python_semantic/resources/mdtest/suppressions/type_ignore.md

@@ -96,6 +96,8 @@ a = test  # type: ignore[name-defined]
 
 ## Nested comments
 
+<!-- snapshot-diagnostics -->
+
 ```py
 # fmt: off
 a = test \
@@ -103,6 +105,14 @@ a = test \
 
 a = test \
   + 2  # type: ignore # fmt: skip
+
+a = (3
+  # error: [unused-ignore-comment]
+  + 2)  # ty:ignore[division-by-zero] # fmt: skip
+
+a = (3
+  # error: [unused-ignore-comment]
+  + 2)  # fmt: skip # ty:ignore[division-by-zero]
 ```
 
 ## Misspelled `type: ignore`

crates/ty_python_semantic/resources/mdtest/type_of/basic.md

@@ -174,6 +174,39 @@ def _(x: Foo[int], y: Bar[str], z: list[bytes]):
     reveal_type(type(z))  # revealed: type[list[bytes]]
 ```
 
+## Checking generic `type[]` types
+
+```toml
+[environment]
+python-version = "3.12"
+```
+
+```py
+class C[T]:
+    pass
+
+class D[T]:
+    pass
+
+var: type[C[int]] = C[int]
+var: type[C[int]] = D[int]  # error: [invalid-assignment] "Object of type `<class 'D[int]'>` is not assignable to `type[C[int]]`"
+```
+
+However, generic `Protocol` classes are still TODO:
+
+```py
+from typing import Protocol
+
+class Proto[U](Protocol):
+    def some_method(self): ...
+
+# TODO: should be error: [invalid-assignment]
+var: type[Proto[int]] = C[int]
+
+def _(p: type[Proto[int]]):
+    reveal_type(p)  # revealed: type[@Todo(type[T] for protocols)]
+```
+
 ## `@final` classes
 
 `type[]` types are eagerly converted to class-literal types if a class decorated with `@final` is

crates/ty_python_semantic/resources/mdtest/type_properties/constraints.md

@@ -66,12 +66,15 @@ def _[T]() -> None:
     reveal_type(ConstraintSet.range(Base, T, object))
 ```
 
-And a range constraint with _both_ a lower bound of `Never` and an upper bound of `object` does not
-constrain the typevar at all.
+And a range constraint with a lower bound of `Never` and an upper bound of `object` allows the
+typevar to take on any type. We treat this differently than the `always` constraint set. During
+specialization inference, that allows us to distinguish between not constraining a typevar (and
+therefore falling back on its default specialization) and explicitly constraining it to any subtype
+of `object`.
 
 ```py
 def _[T]() -> None:
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@_ = *)]
     reveal_type(ConstraintSet.range(Never, T, object))
 ```
 
@@ -156,7 +159,7 @@ cannot be satisfied at all.
 
 ```py
 def _[T]() -> None:
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@_ ≠ *)]
     reveal_type(~ConstraintSet.range(Never, T, object))
 ```
 
@@ -654,7 +657,7 @@ def _[T]() -> None:
     reveal_type(~ConstraintSet.range(Never, T, Base))
     # revealed: ty_extensions.ConstraintSet[¬(Sub ≤ T@_)]
     reveal_type(~ConstraintSet.range(Sub, T, object))
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@_ ≠ *)]
     reveal_type(~ConstraintSet.range(Never, T, object))
 ```
 
@@ -811,7 +814,7 @@ def f[T]():
     # "domain", which maps valid inputs to `true` and invalid inputs to `false`. This means that two
     # constraint sets that are both always satisfied will not be identical if they have different
     # domains!
-    always = ConstraintSet.range(Never, T, object)
+    always = ConstraintSet.always()
     # revealed: ty_extensions.ConstraintSet[always]
     reveal_type(always)
     static_assert(always)
@@ -846,11 +849,11 @@ from typing import Never
 from ty_extensions import ConstraintSet
 
 def same_typevar[T]():
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Never, T, T))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(T, T, object))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(T, T, T))
 ```
 
@@ -862,11 +865,11 @@ as shown above.)
 from ty_extensions import Intersection
 
 def same_typevar[T]():
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Never, T, T | None))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Intersection[T, None], T, object))
-    # revealed: ty_extensions.ConstraintSet[always]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar = *)]
     reveal_type(ConstraintSet.range(Intersection[T, None], T, T | None))
 ```
 
@@ -877,8 +880,8 @@ constraint set can never be satisfied, since every type is disjoint with its neg
 from ty_extensions import Not
 
 def same_typevar[T]():
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar ≠ *)]
     reveal_type(ConstraintSet.range(Intersection[Not[T], None], T, object))
-    # revealed: ty_extensions.ConstraintSet[never]
+    # revealed: ty_extensions.ConstraintSet[(T@same_typevar ≠ *)]
     reveal_type(ConstraintSet.range(Not[T], T, object))
 ```

crates/ty_python_semantic/resources/mdtest/type_properties/is_assignable_to.md

@@ -243,13 +243,13 @@ static_assert(is_assignable_to(TypeOf[Bar[int]], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar[bool]], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar[Any]], type[Foo[int]]))
+static_assert(is_assignable_to(TypeOf[Bar[Unknown]], type[Foo[int]]))
 static_assert(is_assignable_to(TypeOf[Bar], type[Foo]))
 static_assert(is_assignable_to(TypeOf[Bar[Any]], type[Foo[Any]]))
 static_assert(is_assignable_to(TypeOf[Bar[Any]], type[Foo[int]]))
 
-# TODO: these should pass (all subscripts inside `type[]` type expressions are currently TODO types)
-static_assert(not is_assignable_to(TypeOf[Bar[int]], type[Foo[bool]]))  # error: [static-assert-error]
-static_assert(not is_assignable_to(TypeOf[Foo[bool]], type[Bar[int]]))  # error: [static-assert-error]
+static_assert(not is_assignable_to(TypeOf[Bar[int]], type[Foo[bool]]))
+static_assert(not is_assignable_to(TypeOf[Foo[bool]], type[Bar[int]]))
 ```
 
 ## `type[]` is not assignable to types disjoint from `builtins.type`

crates/ty_python_semantic/resources/mdtest/type_properties/is_equivalent_to.md

@@ -628,8 +628,8 @@ import imported
 from module2 import imported as other_imported
 from ty_extensions import TypeOf, static_assert, is_equivalent_to
 
-# error: [unresolved-attribute]
-reveal_type(imported.abc)  # revealed: Unknown
+# error: [possibly-missing-attribute]
+reveal_type(imported.abc)  # revealed: <module 'imported.abc'>
 
 reveal_type(other_imported.abc)  # revealed: <module 'imported.abc'>
 

crates/ty_python_semantic/resources/mdtest/typed_dict.md

@@ -1407,10 +1407,12 @@ msg.content
 
 ### `typing.TypedDict` is not allowed in type expressions
 
+<!-- snapshot-diagnostics -->
+
 ```py
 from typing import TypedDict
 
-# error: [invalid-type-form] "The special form `typing.TypedDict` is not allowed in type expressions."
+# error: [invalid-type-form] "The special form `typing.TypedDict` is not allowed in type expressions"
 x: TypedDict = {"name": "Alice"}
 ```
 

crates/ty_python_semantic/src/diagnostic.rs

@@ -1,5 +1,11 @@
-use crate::{Db, Program, PythonVersionWithSource};
-use ruff_db::diagnostic::{Annotation, Diagnostic, SubDiagnostic, SubDiagnosticSeverity};
+use crate::{
+    Db, Program, PythonVersionWithSource, lint::lint_documentation_url, types::TypeCheckDiagnostics,
+};
+use ruff_db::{
+    diagnostic::{Annotation, Diagnostic, DiagnosticId, SubDiagnostic, SubDiagnosticSeverity},
+    files::File,
+};
+use std::cell::RefCell;
 use std::fmt::Write;
 
 /// Suggest a name from `existing_names` that is similar to `wrong_name`.
@@ -144,3 +150,129 @@ where
 
     buffer
 }
+
+/// An abstraction for mutating a diagnostic.
+///
+/// Callers likely should use `LintDiagnosticGuard` via
+/// `InferContext::report_lint` instead. This guard is only intended for use
+/// with non-lint diagnostics or non-type checking diagnostics. It is fundamentally lower level and easier to
+/// get things wrong by using it.
+///
+/// Unlike `LintDiagnosticGuard`, this API does not guarantee that the
+/// constructed `Diagnostic` not only has a primary annotation, but its
+/// associated file is equivalent to the file being type checked. As a result,
+/// if either is violated, then the `Drop` impl on `DiagnosticGuard` will
+/// panic.
+pub(super) struct DiagnosticGuard<'sink> {
+    /// The file of the primary span (to which file does this diagnostic belong).
+    file: File,
+
+    /// The target where to emit the diagnostic to.
+    ///
+    /// We use a [`RefCell`] here over a `&mut TypeCheckDiagnostics` to ensure the fact that
+    /// `InferContext` (and other contexts with diagnostics) use a [`RefCell`] internally
+    /// remains abstracted away. Specifically, we want to ensure that calling `report_lint` on
+    /// `InferContext` twice doesn't result in a panic:
+    ///
+    /// ```ignore
+    /// let diag1 = context.report_lint(...);
+    ///
+    /// // would panic if using a `&mut TypeCheckDiagnostics`
+    /// // because of a second mutable borrow.
+    /// let diag2 = context.report_lint(...);
+    /// ```
+    sink: &'sink RefCell<TypeCheckDiagnostics>,
+
+    /// The diagnostic that we want to report.
+    ///
+    /// This is always `Some` until the `Drop` impl.
+    diag: Option<Diagnostic>,
+}
+
+impl<'sink> DiagnosticGuard<'sink> {
+    pub(crate) fn new(
+        file: File,
+        sink: &'sink std::cell::RefCell<TypeCheckDiagnostics>,
+        diag: Diagnostic,
+    ) -> Self {
+        Self {
+            file,
+            sink,
+            diag: Some(diag),
+        }
+    }
+}
+
+impl std::ops::Deref for DiagnosticGuard<'_> {
+    type Target = Diagnostic;
+
+    fn deref(&self) -> &Diagnostic {
+        // OK because `self.diag` is only `None` within `Drop`.
+        self.diag.as_ref().unwrap()
+    }
+}
+
+/// Return a mutable borrow of the diagnostic in this guard.
+///
+/// Callers may mutate the diagnostic to add new sub-diagnostics
+/// or annotations.
+///
+/// The diagnostic is added to the typing context, if appropriate,
+/// when this guard is dropped.
+impl std::ops::DerefMut for DiagnosticGuard<'_> {
+    fn deref_mut(&mut self) -> &mut Diagnostic {
+        // OK because `self.diag` is only `None` within `Drop`.
+        self.diag.as_mut().unwrap()
+    }
+}
+
+/// Finishes use of this guard.
+///
+/// This will add the diagnostic to the typing context if appropriate.
+///
+/// # Panics
+///
+/// This panics when the underlying diagnostic lacks a primary
+/// annotation, or if it has one and its file doesn't match the file
+/// being type checked.
+impl Drop for DiagnosticGuard<'_> {
+    fn drop(&mut self) {
+        if std::thread::panicking() {
+            // Don't submit diagnostics when panicking because they might be incomplete.
+            return;
+        }
+
+        // OK because the only way `self.diag` is `None`
+        // is via this impl, which can only run at most
+        // once.
+        let mut diag = self.diag.take().unwrap();
+
+        let Some(ann) = diag.primary_annotation() else {
+            panic!(
+                "All diagnostics reported by `InferContext` must have a \
+                 primary annotation, but diagnostic {id} does not",
+                id = diag.id(),
+            );
+        };
+
+        let expected_file = self.file;
+        let got_file = ann.get_span().expect_ty_file();
+        assert_eq!(
+            expected_file,
+            got_file,
+            "All diagnostics reported by `InferContext` must have a \
+             primary annotation whose file matches the file of the \
+             current typing context, but diagnostic {id} has file \
+             {got_file:?} and we expected {expected_file:?}",
+            id = diag.id(),
+        );
+
+        if let DiagnosticId::Lint(lint_name) = diag.id()
+            && diag.documentation_url().is_none()
+        {
+            diag.set_documentation_url(Some(lint_documentation_url(lint_name)));
+        }
+
+        self.sink.borrow_mut().push(diag);
+    }
+}

crates/ty_python_semantic/src/lib.rs

@@ -12,8 +12,8 @@ pub use db::Db;
 pub use diagnostic::add_inferred_python_version_hint_to_diagnostic;
 pub use module_name::{ModuleName, ModuleNameResolutionError};
 pub use module_resolver::{
-    Module, SearchPath, SearchPathValidationError, SearchPaths, all_modules, list_modules,
-    resolve_module, resolve_real_module, system_module_search_paths,
+    KnownModule, Module, SearchPath, SearchPathValidationError, SearchPaths, all_modules,
+    list_modules, resolve_module, resolve_real_module, system_module_search_paths,
 };
 pub use program::{
     Program, ProgramSettings, PythonVersionFileSource, PythonVersionSource,

crates/ty_python_semantic/src/module_resolver/mod.rs

@@ -1,7 +1,7 @@
 use std::iter::FusedIterator;
 
 pub use list::{all_modules, list_modules};
-pub(crate) use module::KnownModule;
+pub use module::KnownModule;
 pub use module::Module;
 pub use path::{SearchPath, SearchPathValidationError};
 pub use resolver::SearchPaths;

crates/ty_python_semantic/src/module_resolver/module.rs

@@ -67,7 +67,7 @@ impl<'db> Module<'db> {
     }
 
     /// Does this module represent the given known module?
-    pub(crate) fn is_known(self, db: &'db dyn Database, known_module: KnownModule) -> bool {
+    pub fn is_known(self, db: &'db dyn Database, known_module: KnownModule) -> bool {
         self.known(db) == Some(known_module)
     }
 

crates/ty_python_semantic/src/place.rs

@@ -87,7 +87,7 @@ impl TypeOrigin {
 /// bound_or_declared:   Place::Defined(Literal[1], TypeOrigin::Inferred, Definedness::PossiblyUndefined),
 /// non_existent:        Place::Undefined,
 /// ```
-#[derive(Debug, Clone, PartialEq, Eq, salsa::Update, get_size2::GetSize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, salsa::Update, get_size2::GetSize)]
 pub(crate) enum Place<'db> {
     Defined(Type<'db>, TypeOrigin, Definedness),
     Undefined,
@@ -532,7 +532,7 @@ impl<'db> PlaceFromDeclarationsResult<'db> {
 /// that this comes with a [`CLASS_VAR`] type qualifier.
 ///
 /// [`CLASS_VAR`]: crate::types::TypeQualifiers::CLASS_VAR
-#[derive(Debug, Clone, PartialEq, Eq, salsa::Update, get_size2::GetSize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, salsa::Update, get_size2::GetSize)]
 pub(crate) struct PlaceAndQualifiers<'db> {
     pub(crate) place: Place<'db>,
     pub(crate) qualifiers: TypeQualifiers,
@@ -689,6 +689,51 @@ impl<'db> PlaceAndQualifiers<'db> {
             .or_else(|lookup_error| lookup_error.or_fall_back_to(db, fallback_fn()))
             .into()
     }
+
+    pub(crate) fn cycle_normalized(
+        self,
+        db: &'db dyn Db,
+        previous_place: Self,
+        cycle: &salsa::Cycle,
+    ) -> Self {
+        let place = match (previous_place.place, self.place) {
+            // In fixed-point iteration of type inference, the member type must be monotonically widened and not "oscillate".
+            // Here, monotonicity is guaranteed by pre-unioning the type of the previous iteration into the current result.
+            (Place::Defined(prev_ty, _, _), Place::Defined(ty, origin, definedness)) => {
+                Place::Defined(ty.cycle_normalized(db, prev_ty, cycle), origin, definedness)
+            }
+            // If a `Place` in the current cycle is `Defined` but `Undefined` in the previous cycle,
+            // that means that its definedness depends on the truthiness of the previous cycle value.
+            // In this case, the definedness of the current cycle `Place` is set to `PossiblyUndefined`.
+            // Actually, this branch is unreachable. We evaluate the truthiness of non-definitely-bound places as Ambiguous (see #19579),
+            // so convergence is guaranteed without resorting to this handling.
+            // However, the handling described above may reduce the exactness of reachability analysis,
+            // so it may be better to remove it. In that case, this branch is necessary.
+            (Place::Undefined, Place::Defined(ty, origin, _definedness)) => Place::Defined(
+                ty.recursive_type_normalized(db, cycle),
+                origin,
+                Definedness::PossiblyUndefined,
+            ),
+            // If a `Place` that was `Defined(Divergent)` in the previous cycle is actually found to be unreachable in the current cycle,
+            // it is set to `Undefined` (because the cycle initial value does not include meaningful reachability information).
+            (Place::Defined(ty, origin, _definedness), Place::Undefined) => {
+                if cycle.head_ids().any(|id| ty == Type::divergent(id)) {
+                    Place::Undefined
+                } else {
+                    Place::Defined(
+                        ty.recursive_type_normalized(db, cycle),
+                        origin,
+                        Definedness::PossiblyUndefined,
+                    )
+                }
+            }
+            (Place::Undefined, Place::Undefined) => Place::Undefined,
+        };
+        PlaceAndQualifiers {
+            place,
+            qualifiers: self.qualifiers,
+        }
+    }
 }
 
 impl<'db> From<Place<'db>> for PlaceAndQualifiers<'db> {
@@ -699,16 +744,30 @@ impl<'db> From<Place<'db>> for PlaceAndQualifiers<'db> {
 
 fn place_cycle_initial<'db>(
     _db: &'db dyn Db,
-    _id: salsa::Id,
+    id: salsa::Id,
     _scope: ScopeId<'db>,
     _place_id: ScopedPlaceId,
     _requires_explicit_reexport: RequiresExplicitReExport,
     _considered_definitions: ConsideredDefinitions,
 ) -> PlaceAndQualifiers<'db> {
-    Place::bound(Type::Never).into()
+    Place::bound(Type::divergent(id)).into()
 }
 
-#[salsa::tracked(cycle_initial=place_cycle_initial, heap_size=ruff_memory_usage::heap_size)]
+#[allow(clippy::too_many_arguments)]
+fn place_cycle_recover<'db>(
+    db: &'db dyn Db,
+    cycle: &salsa::Cycle,
+    previous_place: &PlaceAndQualifiers<'db>,
+    place: PlaceAndQualifiers<'db>,
+    _scope: ScopeId<'db>,
+    _place_id: ScopedPlaceId,
+    _requires_explicit_reexport: RequiresExplicitReExport,
+    _considered_definitions: ConsideredDefinitions,
+) -> PlaceAndQualifiers<'db> {
+    place.cycle_normalized(db, *previous_place, cycle)
+}
+
+#[salsa::tracked(cycle_fn=place_cycle_recover, cycle_initial=place_cycle_initial, heap_size=ruff_memory_usage::heap_size)]
 pub(crate) fn place_by_id<'db>(
     db: &'db dyn Db,
     scope: ScopeId<'db>,
@@ -1376,9 +1435,7 @@ mod implicit_globals {
     use crate::place::{Definedness, PlaceAndQualifiers, TypeOrigin};
     use crate::semantic_index::symbol::Symbol;
     use crate::semantic_index::{place_table, use_def_map};
-    use crate::types::{
-        CallableType, KnownClass, MemberLookupPolicy, Parameter, Parameters, Signature, Type,
-    };
+    use crate::types::{KnownClass, MemberLookupPolicy, Parameter, Parameters, Signature, Type};
     use ruff_python_ast::PythonVersion;
 
     use super::{Place, place_from_declarations};
@@ -1461,7 +1518,7 @@ mod implicit_globals {
                     )),
                 );
                 Place::Defined(
-                    CallableType::function_like(db, signature),
+                    Type::function_like_callable(db, signature),
                     TypeOrigin::Inferred,
                     Definedness::PossiblyUndefined,
                 )

crates/ty_python_semantic/src/semantic_index.rs

@@ -79,7 +79,10 @@ pub(crate) fn place_table<'db>(db: &'db dyn Db, scope: ScopeId<'db>) -> Arc<Plac
 /// See [`ModuleLiteralType::available_submodule_attributes`] for discussion
 /// of why this analysis is intentionally limited.
 #[salsa::tracked(returns(deref), heap_size=ruff_memory_usage::heap_size)]
-pub(crate) fn imported_modules<'db>(db: &'db dyn Db, file: File) -> Arc<FxHashSet<ModuleName>> {
+pub(crate) fn imported_modules<'db>(
+    db: &'db dyn Db,
+    file: File,
+) -> Arc<FxHashMap<ModuleName, ImportKind>> {
     semantic_index(db, file).imported_modules.clone()
 }
 
@@ -249,7 +252,7 @@ pub(crate) struct SemanticIndex<'db> {
     ast_ids: IndexVec<FileScopeId, AstIds>,
 
     /// The set of modules that are imported anywhere within this file.
-    imported_modules: Arc<FxHashSet<ModuleName>>,
+    imported_modules: Arc<FxHashMap<ModuleName, ImportKind>>,
 
     /// Flags about the global scope (code usage impacting inference)
     has_future_annotations: bool,
@@ -586,6 +589,12 @@ impl<'db> SemanticIndex<'db> {
     }
 }
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, get_size2::GetSize)]
+pub(crate) enum ImportKind {
+    Import,
+    ImportFrom,
+}
+
 pub(crate) struct AncestorsIter<'a> {
     scopes: &'a IndexSlice<FileScopeId, Scope>,
     next_id: Option<FileScopeId>,

crates/ty_python_semantic/src/semantic_index/builder.rs

@@ -47,7 +47,7 @@ use crate::semantic_index::symbol::{ScopedSymbolId, Symbol};
 use crate::semantic_index::use_def::{
     EnclosingSnapshotKey, FlowSnapshot, ScopedEnclosingSnapshotId, UseDefMapBuilder,
 };
-use crate::semantic_index::{ExpressionsScopeMap, SemanticIndex, VisibleAncestorsIter};
+use crate::semantic_index::{ExpressionsScopeMap, ImportKind, SemanticIndex, VisibleAncestorsIter};
 use crate::semantic_model::HasTrackedScope;
 use crate::unpack::{EvaluationMode, Unpack, UnpackKind, UnpackPosition, UnpackValue};
 use crate::{Db, Program};
@@ -110,7 +110,7 @@ pub(super) struct SemanticIndexBuilder<'db, 'ast> {
     scopes_by_expression: ExpressionsScopeMapBuilder,
     definitions_by_node: FxHashMap<DefinitionNodeKey, Definitions<'db>>,
     expressions_by_node: FxHashMap<ExpressionNodeKey, Expression<'db>>,
-    imported_modules: FxHashSet<ModuleName>,
+    imported_modules: FxHashMap<ModuleName, ImportKind>,
     seen_submodule_imports: FxHashSet<String>,
     /// Hashset of all [`FileScopeId`]s that correspond to [generator functions].
     ///
@@ -150,7 +150,7 @@ impl<'db, 'ast> SemanticIndexBuilder<'db, 'ast> {
             expressions_by_node: FxHashMap::default(),
 
             seen_submodule_imports: FxHashSet::default(),
-            imported_modules: FxHashSet::default(),
+            imported_modules: FxHashMap::default(),
             generator_functions: FxHashSet::default(),
 
             enclosing_snapshots: FxHashMap::default(),
@@ -1472,7 +1472,11 @@ impl<'ast> Visitor<'ast> for SemanticIndexBuilder<'_, 'ast> {
                     // Mark the imported module, and all of its parents, as being imported in this
                     // file.
                     if let Some(module_name) = ModuleName::new(&alias.name) {
-                        self.imported_modules.extend(module_name.ancestors());
+                        self.imported_modules.extend(
+                            module_name
+                                .ancestors()
+                                .zip(std::iter::repeat(ImportKind::Import)),
+                        );
                     }
 
                     let (symbol_name, is_reexported) = if let Some(asname) = &alias.asname {
@@ -1513,33 +1517,54 @@ impl<'ast> Visitor<'ast> for SemanticIndexBuilder<'_, 'ast> {
                 // that `x` can be freely overwritten, and that we don't assume that an import
                 // in one function is visible in another function.
                 let mut is_self_import = false;
-                if self.file.is_package(self.db)
-                    && let Ok(module_name) = ModuleName::from_identifier_parts(
-                        self.db,
-                        self.file,
-                        node.module.as_deref(),
-                        node.level,
-                    )
-                    && let Ok(thispackage) = ModuleName::package_for_file(self.db, self.file)
-                {
+                let is_package = self.file.is_package(self.db);
+                let this_package = ModuleName::package_for_file(self.db, self.file);
+
+                if let Ok(module_name) = ModuleName::from_identifier_parts(
+                    self.db,
+                    self.file,
+                    node.module.as_deref(),
+                    node.level,
+                ) {
                     // Record whether this is equivalent to `from . import ...`
-                    is_self_import = module_name == thispackage;
+                    if is_package && let Ok(thispackage) = this_package.as_ref() {
+                        is_self_import = &module_name == thispackage;
+                    }
 
-                    if node.module.is_some()
-                        && let Some(relative_submodule) = module_name.relative_to(&thispackage)
-                        && let Some(direct_submodule) = relative_submodule.components().next()
-                        && !self.seen_submodule_imports.contains(direct_submodule)
-                        && self.current_scope().is_global()
-                    {
-                        self.seen_submodule_imports
-                            .insert(direct_submodule.to_owned());
+                    if node.module.is_some() {
+                        if is_package
+                            && let Ok(thispackage) = this_package
+                            && self.current_scope().is_global()
+                            && let Some(relative_submodule) = module_name.relative_to(&thispackage)
+                            && let Some(direct_submodule) = relative_submodule.components().next()
+                            && !self.seen_submodule_imports.contains(direct_submodule)
+                        {
+                            self.seen_submodule_imports
+                                .insert(direct_submodule.to_owned());
 
-                        let direct_submodule_name = Name::new(direct_submodule);
-                        let symbol = self.add_symbol(direct_submodule_name);
-                        self.add_definition(
-                            symbol.into(),
-                            ImportFromSubmoduleDefinitionNodeRef { node },
-                        );
+                            let direct_submodule_name = Name::new(direct_submodule);
+                            let symbol = self.add_symbol(direct_submodule_name);
+                            self.add_definition(
+                                symbol.into(),
+                                ImportFromSubmoduleDefinitionNodeRef { node },
+                            );
+                        } else {
+                            for name in module_name.ancestors() {
+                                self.imported_modules
+                                    .entry(name)
+                                    .or_insert(ImportKind::ImportFrom);
+                            }
+                            for name in &node.names {
+                                let Some(relative_name) = ModuleName::new(&name.name) else {
+                                    continue;
+                                };
+                                let mut full_name = module_name.clone();
+                                full_name.extend(&relative_name);
+                                self.imported_modules
+                                    .entry(full_name)
+                                    .or_insert(ImportKind::ImportFrom);
+                            }
+                        }
                     }
                 }
 
@@ -2255,6 +2280,8 @@ impl<'ast> Visitor<'ast> for SemanticIndexBuilder<'_, 'ast> {
                 names,
             }) => {
                 for name in names {
+                    self.scopes_by_expression
+                        .record_expression(name, self.current_scope());
                     let symbol_id = self.add_symbol(name.id.clone());
                     let symbol = self.current_place_table().symbol(symbol_id);
                     // Check whether the variable has already been accessed in this scope.
@@ -2290,6 +2317,8 @@ impl<'ast> Visitor<'ast> for SemanticIndexBuilder<'_, 'ast> {
                 names,
             }) => {
                 for name in names {
+                    self.scopes_by_expression
+                        .record_expression(name, self.current_scope());
                     let symbol_id = self.add_symbol(name.id.clone());
                     let symbol = self.current_place_table().symbol(symbol_id);
                     // Check whether the variable has already been accessed in this scope.

crates/ty_python_semantic/src/semantic_index/reachability_constraints.rs

@@ -208,7 +208,7 @@ use crate::semantic_index::predicate::{
     Predicates, ScopedPredicateId,
 };
 use crate::types::{
-    IntersectionBuilder, Truthiness, Type, TypeContext, UnionBuilder, UnionType,
+    CallableTypes, IntersectionBuilder, Truthiness, Type, TypeContext, UnionBuilder, UnionType,
     infer_expression_type, static_expression_truthiness,
 };
 
@@ -871,12 +871,14 @@ impl ReachabilityConstraints {
                     return Truthiness::AlwaysFalse.negate_if(!predicate.is_positive);
                 }
 
-                let overloads_iterator =
-                    if let Some(Type::Callable(callable)) = ty.try_upcast_to_callable(db) {
-                        callable.signatures(db).overloads.iter()
-                    } else {
-                        return Truthiness::AlwaysFalse.negate_if(!predicate.is_positive);
-                    };
+                let overloads_iterator = if let Some(callable) = ty
+                    .try_upcast_to_callable(db)
+                    .and_then(CallableTypes::exactly_one)
+                {
+                    callable.signatures(db).overloads.iter()
+                } else {
+                    return Truthiness::AlwaysFalse.negate_if(!predicate.is_positive);
+                };
 
                 let (no_overloads_return_never, all_overloads_return_never) = overloads_iterator
                     .fold((true, true), |(none, all), overload| {

crates/ty_python_semantic/src/semantic_model.rs

@@ -1,7 +1,8 @@
 use ruff_db::files::{File, FilePath};
-use ruff_db::source::line_index;
-use ruff_python_ast as ast;
+use ruff_db::source::{line_index, source_text};
+use ruff_python_ast::{self as ast, ExprStringLiteral, ModExpression};
 use ruff_python_ast::{Expr, ExprRef, HasNodeIndex, name::Name};
+use ruff_python_parser::Parsed;
 use ruff_source_file::LineIndex;
 use rustc_hash::FxHashMap;
 
@@ -11,22 +12,37 @@ use crate::module_resolver::{KnownModule, Module, list_modules, resolve_module};
 use crate::semantic_index::definition::Definition;
 use crate::semantic_index::scope::FileScopeId;
 use crate::semantic_index::semantic_index;
-use crate::types::ide_support::all_declarations_and_bindings;
-use crate::types::ide_support::{Member, all_members};
+use crate::types::ide_support::{Member, all_declarations_and_bindings, all_members};
 use crate::types::{Type, binding_type, infer_scope_types};
 
+/// The primary interface the LSP should use for querying semantic information about a [`File`].
+///
+/// Although you can in principle freely construct this type given a `db` and `file`, you should
+/// try to construct this at the start of your analysis and thread the same instance through
+/// the full analysis.
+///
+/// The primary reason for this is that it manages traversing into the sub-ASTs of string
+/// annotations (see [`Self::enter_string_annotation`]). When you do this you will be handling
+/// AST nodes that don't belong to the file's AST (or *any* file's AST). These kinds of nodes
+/// will result in panics and confusing results if handed to the wrong subsystem. `SemanticModel`
+/// methods will automatically handle using the string literal's AST node when necessary.
 pub struct SemanticModel<'db> {
     db: &'db dyn Db,
     file: File,
+    /// If `Some` then this `SemanticModel` is for analyzing the sub-AST of a string annotation.
+    /// This expression will be used as a witness to the scope/location we're analyzing.
+    in_string_annotation_expr: Option<Box<Expr>>,
 }
 
 impl<'db> SemanticModel<'db> {
     pub fn new(db: &'db dyn Db, file: File) -> Self {
-        Self { db, file }
+        Self {
+            db,
+            file,
+            in_string_annotation_expr: None,
+        }
     }
 
-    // TODO we don't actually want to expose the Db directly to lint rules, but we need to find a
-    // solution for exposing information from types
     pub fn db(&self) -> &'db dyn Db {
         self.db
     }
@@ -213,10 +229,10 @@ impl<'db> SemanticModel<'db> {
         completions
     }
 
-    fn scope(&self, node: ast::AnyNodeRef<'_>) -> Option<FileScopeId> {
+    /// Get the scope of the given node (handles string annotations)
+    pub fn scope(&self, node: ast::AnyNodeRef<'_>) -> Option<FileScopeId> {
         let index = semantic_index(self.db, self.file);
-
-        match node {
+        match self.node_in_ast(node) {
             ast::AnyNodeRef::Identifier(identifier) => index.try_expression_scope_id(identifier),
             node => match node.as_expr_ref() {
                 // If we couldn't identify a specific
@@ -227,6 +243,82 @@ impl<'db> SemanticModel<'db> {
             },
         }
     }
+
+    /// Get a "safe" [`ast::AnyNodeRef`] to use for referring to the given (sub-)AST node.
+    ///
+    /// If we're analyzing a string annotation, it will return the string literal's node.
+    /// Otherwise it will return the input.
+    pub fn node_in_ast<'a>(&'a self, node: ast::AnyNodeRef<'a>) -> ast::AnyNodeRef<'a> {
+        if let Some(string_annotation) = &self.in_string_annotation_expr {
+            (&**string_annotation).into()
+        } else {
+            node
+        }
+    }
+
+    /// Get a "safe" [`Expr`] to use for referring to the given (sub-)expression.
+    ///
+    /// If we're analyzing a string annotation, it will return the string literal's expression.
+    /// Otherwise it will return the input.
+    pub fn expr_in_ast<'a>(&'a self, expr: &'a Expr) -> &'a Expr {
+        if let Some(string_annotation) = &self.in_string_annotation_expr {
+            string_annotation
+        } else {
+            expr
+        }
+    }
+
+    /// Get a "safe" [`ExprRef`] to use for referring to the given (sub-)expression.
+    ///
+    /// If we're analyzing a string annotation, it will return the string literal's expression.
+    /// Otherwise it will return the input.
+    pub fn expr_ref_in_ast<'a>(&'a self, expr: ExprRef<'a>) -> ExprRef<'a> {
+        if let Some(string_annotation) = &self.in_string_annotation_expr {
+            ExprRef::from(string_annotation)
+        } else {
+            expr
+        }
+    }
+
+    /// Given a string expression, determine if it's a string annotation, and if it is,
+    /// yield the parsed sub-AST and a sub-model that knows it's analyzing a sub-AST.
+    ///
+    /// Analysis of the sub-AST should only be done with the sub-model, or else things
+    /// may return nonsense results or even panic!
+    pub fn enter_string_annotation(
+        &self,
+        string_expr: &ExprStringLiteral,
+    ) -> Option<(Parsed<ModExpression>, Self)> {
+        // String annotations can't contain string annotations
+        if self.in_string_annotation_expr.is_some() {
+            return None;
+        }
+
+        // Ask the inference engine whether this is actually a string annotation
+        let expr = ExprRef::StringLiteral(string_expr);
+        let index = semantic_index(self.db, self.file);
+        let file_scope = index.expression_scope_id(&expr);
+        let scope = file_scope.to_scope_id(self.db, self.file);
+        if !infer_scope_types(self.db, scope).is_string_annotation(expr) {
+            return None;
+        }
+
+        // Parse the sub-AST and create a semantic model that knows it's in a sub-AST
+        //
+        // The string_annotation will be used as the expr/node for any query that needs
+        // to look up a node in the AST to prevent panics, because these sub-AST nodes
+        // are not in the File's AST!
+        let source = source_text(self.db, self.file);
+        let string_literal = string_expr.as_single_part_string()?;
+        let ast =
+            ruff_python_parser::parse_string_annotation(source.as_str(), string_literal).ok()?;
+        let model = Self {
+            db: self.db,
+            file: self.file,
+            in_string_annotation_expr: Some(Box::new(Expr::StringLiteral(string_expr.clone()))),
+        };
+        Some((ast, model))
+    }
 }
 
 /// The type and definition (if available) of a symbol.
@@ -315,7 +407,13 @@ pub trait HasDefinition {
 impl HasType for ast::ExprRef<'_> {
     fn inferred_type<'db>(&self, model: &SemanticModel<'db>) -> Type<'db> {
         let index = semantic_index(model.db, model.file);
-        let file_scope = index.expression_scope_id(self);
+        // TODO(#1637): semantic tokens is making this crash even with
+        // `try_expr_ref_in_ast` guarding this, for now just use `try_expression_scope_id`.
+        // The problematic input is `x: "float` (with a dangling quote). I imagine the issue
+        // is we're too eagerly setting `is_string_annotation` in inference.
+        let Some(file_scope) = index.try_expression_scope_id(&model.expr_ref_in_ast(*self)) else {
+            return Type::unknown();
+        };
         let scope = file_scope.to_scope_id(model.db, model.file);
 
         infer_scope_types(model.db, scope).expression_type(*self)

crates/ty_python_semantic/src/suppression.rs

@@ -1,17 +1,24 @@
-use crate::lint::{GetLintError, Level, LintMetadata, LintRegistry, LintStatus};
-use crate::types::TypeCheckDiagnostics;
-use crate::{Db, declare_lint, lint::LintId};
-use ruff_db::diagnostic::{Annotation, Diagnostic, DiagnosticId, IntoDiagnosticMessage, Span};
-use ruff_db::{files::File, parsed::parsed_module, source::source_text};
-use ruff_python_parser::TokenKind;
-use ruff_python_trivia::Cursor;
-use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
 use smallvec::{SmallVec, smallvec};
 use std::error::Error;
 use std::fmt;
 use std::fmt::Formatter;
+use std::fmt::Write as _;
 use thiserror::Error;
 
+use crate::diagnostic::DiagnosticGuard;
+use crate::lint::{GetLintError, Level, LintMetadata, LintRegistry, LintStatus};
+use crate::types::TypeCheckDiagnostics;
+use crate::{Db, declare_lint, lint::LintId};
+
+use ruff_db::diagnostic::{
+    Annotation, Diagnostic, DiagnosticId, IntoDiagnosticMessage, Severity, Span,
+};
+use ruff_db::{files::File, parsed::parsed_module, source::source_text};
+use ruff_diagnostics::{Edit, Fix};
+use ruff_python_parser::TokenKind;
+use ruff_python_trivia::Cursor;
+use ruff_text_size::{Ranged, TextLen, TextRange, TextSize};
+
 declare_lint! {
     /// ## What it does
     /// Checks for `type: ignore` or `ty: ignore` directives that are no longer applicable.
@@ -106,7 +113,7 @@ pub(crate) fn suppressions(db: &dyn Db, file: File) -> Suppressions {
                 for comment in parser {
                     match comment {
                         Ok(comment) => {
-                            builder.add_comment(&comment, TextRange::new(line_start, token.end()));
+                            builder.add_comment(comment, TextRange::new(line_start, token.end()));
                         }
                         Err(error) => match error.kind {
                             ParseErrorKind::NotASuppression
@@ -133,12 +140,18 @@ pub(crate) fn suppressions(db: &dyn Db, file: File) -> Suppressions {
     builder.finish()
 }
 
-pub(crate) fn check_suppressions(db: &dyn Db, file: File, diagnostics: &mut TypeCheckDiagnostics) {
+pub(crate) fn check_suppressions(
+    db: &dyn Db,
+    file: File,
+    diagnostics: TypeCheckDiagnostics,
+) -> Vec<Diagnostic> {
     let mut context = CheckSuppressionsContext::new(db, file, diagnostics);
 
     check_unknown_rule(&mut context);
     check_invalid_suppression(&mut context);
     check_unused_suppressions(&mut context);
+
+    context.diagnostics.into_inner().into_diagnostics()
 }
 
 /// Checks for `ty: ignore` comments that reference unknown rules.
@@ -148,7 +161,9 @@ fn check_unknown_rule(context: &mut CheckSuppressionsContext) {
     }
 
     for unknown in &context.suppressions.unknown {
-        context.report_lint(&IGNORE_COMMENT_UNKNOWN_RULE, unknown.range, &unknown.reason);
+        if let Some(diag) = context.report_lint(&IGNORE_COMMENT_UNKNOWN_RULE, unknown.range) {
+            diag.into_diagnostic(&unknown.reason);
+        }
     }
 }
 
@@ -158,15 +173,13 @@ fn check_invalid_suppression(context: &mut CheckSuppressionsContext) {
     }
 
     for invalid in &context.suppressions.invalid {
-        context.report_lint(
-            &INVALID_IGNORE_COMMENT,
-            invalid.error.range,
-            format_args!(
+        if let Some(diag) = context.report_lint(&INVALID_IGNORE_COMMENT, invalid.error.range) {
+            diag.into_diagnostic(format_args!(
                 "Invalid `{kind}` comment: {reason}",
                 kind = invalid.kind,
                 reason = &invalid.error
-            ),
-        );
+            ));
+        }
     }
 }
 
@@ -179,17 +192,19 @@ fn check_unused_suppressions(context: &mut CheckSuppressionsContext) {
         return;
     }
 
+    let diagnostics = context.diagnostics.get_mut();
+
     let all = context.suppressions;
     let mut unused = Vec::with_capacity(
         all.file
             .len()
             .saturating_add(all.line.len())
-            .saturating_sub(context.diagnostics.used_len()),
+            .saturating_sub(diagnostics.used_len()),
     );
 
     // Collect all suppressions that are unused after type-checking.
     for suppression in all {
-        if context.diagnostics.is_used(suppression.id()) {
+        if diagnostics.is_used(suppression.id()) {
             continue;
         }
 
@@ -203,7 +218,7 @@ fn check_unused_suppressions(context: &mut CheckSuppressionsContext) {
             // A `unused-ignore-comment` suppression can't ignore itself.
             // It can only ignore other suppressions.
             if unused_suppression.id() != suppression.id() {
-                context.diagnostics.mark_used(unused_suppression.id());
+                diagnostics.mark_used(unused_suppression.id());
                 continue;
             }
         }
@@ -211,37 +226,152 @@ fn check_unused_suppressions(context: &mut CheckSuppressionsContext) {
         unused.push(suppression);
     }
 
-    for suppression in unused {
-        // This looks silly but it's necessary to check again if a `unused-ignore-comment` is indeed unused
-        // in case the "unused" directive comes after it:
-        // ```py
-        // a = 10 / 2  # ty: ignore[unused-ignore-comment, division-by-zero]
-        // ```
-        if context.diagnostics.is_used(suppression.id()) {
-            continue;
-        }
+    let mut unused_iter = unused
+        .iter()
+        .filter(|suppression| {
+            // This looks silly but it's necessary to check again if a `unused-ignore-comment` is indeed unused
+            // in case the "unused" directive comes after it:
+            // ```py
+            // a = 10 / 2  # ty: ignore[unused-ignore-comment, division-by-zero]
+            // ```
+            !context.is_suppression_used(suppression.id())
+        })
+        .peekable();
 
-        match suppression.target {
-            SuppressionTarget::All => context.report_unchecked(
-                &UNUSED_IGNORE_COMMENT,
-                suppression.range,
-                format_args!("Unused blanket `{}` directive", suppression.kind),
-            ),
-            SuppressionTarget::Lint(lint) => context.report_unchecked(
-                &UNUSED_IGNORE_COMMENT,
-                suppression.range,
-                format_args!(
-                    "Unused `{kind}` directive: '{code}'",
-                    kind = suppression.kind,
-                    code = lint.name()
-                ),
-            ),
-            SuppressionTarget::Empty => context.report_unchecked(
-                &UNUSED_IGNORE_COMMENT,
-                suppression.range,
-                format_args!("Unused `{kind}` without a code", kind = suppression.kind),
-            ),
-        }
+    let source = source_text(context.db, context.file);
+
+    while let Some(suppression) = unused_iter.next() {
+        let mut diag = match suppression.target {
+            SuppressionTarget::All => {
+                let Some(diag) =
+                    context.report_unchecked(&UNUSED_IGNORE_COMMENT, suppression.range)
+                else {
+                    continue;
+                };
+
+                diag.into_diagnostic(format_args!(
+                    "Unused blanket `{}` directive",
+                    suppression.kind
+                ))
+            }
+            SuppressionTarget::Lint(lint) => {
+                // A single code in a `ty: ignore[<code1>, <code2>, ...]` directive
+
+                // Is this the first code directly after the `[`?
+                let includes_first_code = source[..suppression.range.start().to_usize()]
+                    .trim_end()
+                    .ends_with('[');
+
+                let mut current = suppression;
+                let mut unused_codes = Vec::new();
+
+                // Group successive codes together into a single diagnostic,
+                // or report the entire directive if all codes are unused.
+                while let Some(next) = unused_iter.peek() {
+                    if let SuppressionTarget::Lint(next_lint) = next.target
+                        && next.comment_range == current.comment_range
+                        && source[TextRange::new(current.range.end(), next.range.start())]
+                            .chars()
+                            .all(|c| c.is_whitespace() || c == ',')
+                    {
+                        unused_codes.push(next_lint);
+                        current = *next;
+                        unused_iter.next();
+                    } else {
+                        break;
+                    }
+                }
+
+                // Is the last suppression code the last code before the closing `]`.
+                let includes_last_code = source[current.range.end().to_usize()..]
+                    .trim_start()
+                    .starts_with(']');
+
+                // If only some codes are unused
+                if !includes_first_code || !includes_last_code {
+                    let mut codes = format!("'{}'", lint.name());
+                    for code in &unused_codes {
+                        let _ = write!(&mut codes, ", '{code}'", code = code.name());
+                    }
+
+                    if let Some(diag) = context.report_unchecked(
+                        &UNUSED_IGNORE_COMMENT,
+                        TextRange::new(suppression.range.start(), current.range.end()),
+                    ) {
+                        let mut diag = diag.into_diagnostic(format_args!(
+                            "Unused `{kind}` directive: {codes}",
+                            kind = suppression.kind
+                        ));
+
+                        diag.primary_annotation_mut()
+                            .unwrap()
+                            .push_tag(ruff_db::diagnostic::DiagnosticTag::Unnecessary);
+
+                        // Delete everything up to the start of the next code.
+                        let trailing_len: TextSize = source[current.range.end().to_usize()..]
+                            .chars()
+                            .take_while(|c: &char| c.is_whitespace() || *c == ',')
+                            .map(TextLen::text_len)
+                            .sum();
+
+                        // If we delete the last codes before `]`, ensure we delete any trailing comma
+                        let leading_len: TextSize = if includes_last_code {
+                            source[..suppression.range.start().to_usize()]
+                                .chars()
+                                .rev()
+                                .take_while(|c: &char| c.is_whitespace() || *c == ',')
+                                .map(TextLen::text_len)
+                                .sum()
+                        } else {
+                            TextSize::default()
+                        };
+
+                        let fix_range = TextRange::new(
+                            suppression.range.start() - leading_len,
+                            current.range.end() + trailing_len,
+                        );
+                        diag.set_fix(Fix::safe_edit(Edit::range_deletion(fix_range)));
+
+                        if unused_codes.is_empty() {
+                            diag.help("Remove the unused suppression code");
+                        } else {
+                            diag.help("Remove the unused suppression codes");
+                        }
+                    }
+
+                    continue;
+                }
+
+                // All codes are unused
+                let Some(diag) =
+                    context.report_unchecked(&UNUSED_IGNORE_COMMENT, suppression.comment_range)
+                else {
+                    continue;
+                };
+
+                diag.into_diagnostic(format_args!(
+                    "Unused `{kind}` directive",
+                    kind = suppression.kind
+                ))
+            }
+            SuppressionTarget::Empty => {
+                let Some(diag) =
+                    context.report_unchecked(&UNUSED_IGNORE_COMMENT, suppression.range)
+                else {
+                    continue;
+                };
+                diag.into_diagnostic(format_args!(
+                    "Unused `{kind}` without a code",
+                    kind = suppression.kind
+                ))
+            }
+        };
+
+        diag.primary_annotation_mut()
+            .unwrap()
+            .push_tag(ruff_db::diagnostic::DiagnosticTag::Unnecessary);
+        diag.set_fix(remove_comment_fix(suppression, &source));
+        diag.help("Remove the unused suppression comment");
     }
 }
 
@@ -249,17 +379,17 @@ struct CheckSuppressionsContext<'a> {
     db: &'a dyn Db,
     file: File,
     suppressions: &'a Suppressions,
-    diagnostics: &'a mut TypeCheckDiagnostics,
+    diagnostics: std::cell::RefCell<TypeCheckDiagnostics>,
 }
 
 impl<'a> CheckSuppressionsContext<'a> {
-    fn new(db: &'a dyn Db, file: File, diagnostics: &'a mut TypeCheckDiagnostics) -> Self {
+    fn new(db: &'a dyn Db, file: File, diagnostics: TypeCheckDiagnostics) -> Self {
         let suppressions = suppressions(db, file);
         Self {
             db,
             file,
             suppressions,
-            diagnostics,
+            diagnostics: diagnostics.into(),
         }
     }
 
@@ -270,38 +400,77 @@ impl<'a> CheckSuppressionsContext<'a> {
             .is_enabled(LintId::of(lint))
     }
 
-    fn report_lint(
-        &mut self,
+    fn is_suppression_used(&self, id: FileSuppressionId) -> bool {
+        self.diagnostics.borrow().is_used(id)
+    }
+
+    fn report_lint<'ctx>(
+        &'ctx self,
         lint: &'static LintMetadata,
         range: TextRange,
-        message: impl IntoDiagnosticMessage,
-    ) {
+    ) -> Option<SuppressionDiagnosticGuardBuilder<'ctx, 'a>> {
         if let Some(suppression) = self.suppressions.find_suppression(range, LintId::of(lint)) {
-            self.diagnostics.mark_used(suppression.id());
-            return;
+            self.diagnostics.borrow_mut().mark_used(suppression.id());
+            return None;
         }
 
-        self.report_unchecked(lint, range, message);
+        self.report_unchecked(lint, range)
     }
 
     /// Reports a diagnostic without checking if the lint at the given range is suppressed or marking
     /// the suppression as used.
-    fn report_unchecked(
-        &mut self,
+    fn report_unchecked<'ctx>(
+        &'ctx self,
         lint: &'static LintMetadata,
         range: TextRange,
-        message: impl IntoDiagnosticMessage,
-    ) {
-        let Some(severity) = self.db.rule_selection(self.file).severity(LintId::of(lint)) else {
-            return;
-        };
+    ) -> Option<SuppressionDiagnosticGuardBuilder<'ctx, 'a>> {
+        SuppressionDiagnosticGuardBuilder::new(self, lint, range)
+    }
+}
 
-        let id = DiagnosticId::Lint(lint.name());
-        let mut diag = Diagnostic::new(id, severity, message);
-        diag.set_documentation_url(Some(lint.documentation_url()));
-        let span = Span::from(self.file).with_range(range);
-        diag.annotate(Annotation::primary(span));
-        self.diagnostics.push(diag);
+/// A builder for constructing a diagnostic guard.
+///
+/// This type exists to separate the phases of "check if a diagnostic should
+/// be reported" and "build the actual diagnostic."
+pub(crate) struct SuppressionDiagnosticGuardBuilder<'ctx, 'db> {
+    ctx: &'ctx CheckSuppressionsContext<'db>,
+    id: DiagnosticId,
+    range: TextRange,
+    severity: Severity,
+}
+
+impl<'ctx, 'db> SuppressionDiagnosticGuardBuilder<'ctx, 'db> {
+    fn new(
+        ctx: &'ctx CheckSuppressionsContext<'db>,
+        lint: &'static LintMetadata,
+        range: TextRange,
+    ) -> Option<Self> {
+        let severity = ctx.db.rule_selection(ctx.file).severity(LintId::of(lint))?;
+
+        Some(Self {
+            ctx,
+            id: DiagnosticId::Lint(lint.name()),
+            severity,
+            range,
+        })
+    }
+
+    /// Create a new guard.
+    ///
+    /// This initializes a new diagnostic using the given message along with
+    /// the ID and severity used to create this builder.
+    ///
+    /// The diagnostic can be further mutated on the guard via its `DerefMut`
+    /// impl to `Diagnostic`.
+    pub(crate) fn into_diagnostic(
+        self,
+        message: impl IntoDiagnosticMessage,
+    ) -> DiagnosticGuard<'ctx> {
+        let mut diag = Diagnostic::new(self.id, self.severity, message);
+
+        let primary_span = Span::from(self.ctx.file).with_range(self.range);
+        diag.annotate(Annotation::primary(primary_span));
+        DiagnosticGuard::new(self.ctx.file, &self.ctx.diagnostics, diag)
     }
 }
 
@@ -404,12 +573,22 @@ pub(crate) struct Suppression {
     target: SuppressionTarget,
     kind: SuppressionKind,
 
-    /// The range of this specific suppression.
-    /// This is the same as `comment_range` except for suppression comments that suppress multiple
-    /// codes. For those, the range is limited to the specific code.
+    /// The range of the code in this suppression.
+    ///
+    /// This is the same as the `comment_range` for the
+    /// targets [`SuppressionTarget::All`] and [`SuppressionTarget::Empty`].
     range: TextRange,
 
     /// The range of the suppression comment.
+    ///
+    /// This isn't the range of the entire comment if this is a nested comment:
+    ///
+    /// ```py
+    /// a # ty: ignore # fmt: off
+    ///   ^^^^^^^^^^^^^
+    /// ```
+    ///
+    /// It doesn't include the range of the nested `# fmt: off` comment.
     comment_range: TextRange,
 
     /// The range for which this suppression applies.
@@ -507,7 +686,7 @@ impl<'a> SuppressionsBuilder<'a> {
         }
     }
 
-    fn add_comment(&mut self, comment: &SuppressionComment, line_range: TextRange) {
+    fn add_comment(&mut self, comment: SuppressionComment, line_range: TextRange) {
         // `type: ignore` comments at the start of the file apply to the entire range.
         // > A # type: ignore comment on a line by itself at the top of a file, before any docstrings,
         // > imports, or other executable code, silences all errors in the file.
@@ -530,7 +709,7 @@ impl<'a> SuppressionsBuilder<'a> {
             }
         };
 
-        match comment.codes.as_deref() {
+        match comment.codes {
             // `type: ignore`
             None => {
                 push_type_ignore_suppression(Suppression {
@@ -556,7 +735,7 @@ impl<'a> SuppressionsBuilder<'a> {
             }
 
             // `ty: ignore[]`
-            Some([]) => {
+            Some(codes) if codes.is_empty() => {
                 self.line.push(Suppression {
                     target: SuppressionTarget::Empty,
                     kind: comment.kind,
@@ -569,25 +748,20 @@ impl<'a> SuppressionsBuilder<'a> {
             // `ty: ignore[a, b]`
             Some(codes) => {
                 for code_range in codes {
-                    let code = &self.source[*code_range];
-                    let range = if codes.len() == 1 {
-                        comment.range
-                    } else {
-                        *code_range
-                    };
+                    let code = &self.source[code_range];
 
                     match self.lint_registry.get(code) {
                         Ok(lint) => {
                             self.line.push(Suppression {
                                 target: SuppressionTarget::Lint(lint),
                                 kind: comment.kind,
-                                range,
+                                range: code_range,
                                 comment_range: comment.range,
                                 suppressed_range,
                             });
                         }
                         Err(error) => self.unknown.push(UnknownSuppression {
-                            range,
+                            range: code_range,
                             comment_range: comment.range,
                             reason: error,
                         }),
@@ -730,8 +904,6 @@ impl<'src> SuppressionParser<'src> {
             self.eat_whitespace();
 
             if !self.cursor.eat_char(',') {
-                self.eat_whitespace();
-
                 if self.cursor.eat_char(']') {
                     break Ok(Some(codes));
                 }
@@ -898,6 +1070,37 @@ enum ParseErrorKind {
     CodesMissingClosingBracket(SuppressionKind),
 }
 
+fn remove_comment_fix(suppression: &Suppression, source: &str) -> Fix {
+    let comment_end = suppression.comment_range.end();
+    let comment_start = suppression.comment_range.start();
+    let after_comment = &source[comment_end.to_usize()..];
+
+    if !after_comment.starts_with(['\n', '\r']) {
+        // For example: `# ty: ignore # fmt: off`
+        // Don't remove the trailing whitespace up to the `ty: ignore` comment
+        return Fix::safe_edit(Edit::range_deletion(suppression.comment_range));
+    }
+
+    // Remove any leading whitespace before the comment
+    // to avoid unnecessary trailing whitespace once the comment is removed
+    let before_comment = &source[..comment_start.to_usize()];
+
+    let mut leading_len = TextSize::default();
+
+    for c in before_comment.chars().rev() {
+        match c {
+            '\n' | '\r' => break,
+            c if c.is_whitespace() => leading_len += c.text_len(),
+            _ => break,
+        }
+    }
+
+    Fix::safe_edit(Edit::range_deletion(TextRange::new(
+        comment_start - leading_len,
+        comment_end,
+    )))
+}
+
 #[cfg(test)]
 mod tests {
     use crate::suppression::{SuppressionComment, SuppressionParser};