From 9aa49139392f2db134adc9cfe15852f55c30b38c Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 10:50:04 -0500
Subject: [PATCH 01/13] add test case from #13824

---
 crates/ruff_linter/src/rules/pyflakes/mod.rs | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/crates/ruff_linter/src/rules/pyflakes/mod.rs b/crates/ruff_linter/src/rules/pyflakes/mod.rs
index c01397206f2be..519ef04036d69 100644
--- a/crates/ruff_linter/src/rules/pyflakes/mod.rs
+++ b/crates/ruff_linter/src/rules/pyflakes/mod.rs
@@ -4221,4 +4221,22 @@ lambda: fu
             &[],
         );
     }
+
+    #[test]
+    fn no_type_check_function() {
+        flakes(
+            r#"
+            from typing import no_type_check
+
+            @no_type_check
+            def f821(arg: "A") -> "R":
+                pass
+
+            @no_type_check
+            def f722(arg: "this isn't python") -> "this isn't python either":
+                pass
+        "#,
+            &[],
+        );
+    }
 }

From 3c5ceab687196acbaf4b1c08bd3ede1ba5a186db Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 10:41:11 -0500
Subject: [PATCH 02/13] skip visit_type_definition in a @no_type_check context

---
 crates/ruff_linter/src/checkers/ast/mod.rs | 10 ++++++++++
 crates/ruff_python_semantic/src/model.rs   |  2 ++
 2 files changed, 12 insertions(+)

diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index 1f02f66f3dccb..773ee3de3381b 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -723,6 +723,13 @@ impl<'a> Visitor<'a> for Checker<'a> {
                 // Visit the decorators and arguments, but avoid the body, which will be
                 // deferred.
                 for decorator in decorator_list {
+                    if decorator
+                        .expression
+                        .as_name_expr()
+                        .is_some_and(|name| name.id.as_str() == "no_type_check")
+                    {
+                        self.semantic.flags |= SemanticModelFlags::NO_TYPE_CHECK;
+                    }
                     self.visit_decorator(decorator);
                 }
 
@@ -1851,6 +1858,9 @@ impl<'a> Checker<'a> {
 
     /// Visit an [`Expr`], and treat it as a type definition.
     fn visit_type_definition(&mut self, expr: &'a Expr) {
+        if !(self.semantic.flags & SemanticModelFlags::NO_TYPE_CHECK).is_empty() {
+            return;
+        }
         let snapshot = self.semantic.flags;
         self.semantic.flags |= SemanticModelFlags::TYPE_DEFINITION;
         self.visit_expr(expr);
diff --git a/crates/ruff_python_semantic/src/model.rs b/crates/ruff_python_semantic/src/model.rs
index 8f3235d7b0715..fe04f10e8b49a 100644
--- a/crates/ruff_python_semantic/src/model.rs
+++ b/crates/ruff_python_semantic/src/model.rs
@@ -2222,6 +2222,8 @@ bitflags! {
         /// [PEP 257]: https://peps.python.org/pep-0257/#what-is-a-docstring
         const ATTRIBUTE_DOCSTRING = 1 << 25;
 
+        const NO_TYPE_CHECK = 1 << 26;
+
         /// The context is in any type annotation.
         const ANNOTATION = Self::TYPING_ONLY_ANNOTATION.bits() | Self::RUNTIME_EVALUATED_ANNOTATION.bits() | Self::RUNTIME_REQUIRED_ANNOTATION.bits();
 

From 1b3ae3628983fe7258a7fb5c5f2eae021a1e3448 Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 11:31:49 -0500
Subject: [PATCH 03/13] add docs to new flag

---
 crates/ruff_python_semantic/src/model.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/crates/ruff_python_semantic/src/model.rs b/crates/ruff_python_semantic/src/model.rs
index fe04f10e8b49a..0eabf141d562d 100644
--- a/crates/ruff_python_semantic/src/model.rs
+++ b/crates/ruff_python_semantic/src/model.rs
@@ -2222,6 +2222,21 @@ bitflags! {
         /// [PEP 257]: https://peps.python.org/pep-0257/#what-is-a-docstring
         const ATTRIBUTE_DOCSTRING = 1 << 25;
 
+        /// The model is in a [no_type_check] context.
+        ///
+        /// This is used to skip type checking when the `@no_type_check` decorator is found.
+        ///
+        /// For example (adapted from [#13824]):
+        /// ```python
+        /// from typing import no_type_check
+        ///
+        /// @no_type_check
+        /// def fn(arg: "A") -> "R":
+        ///     pass
+        /// ```
+        ///
+        /// [no_type_check]: https://docs.python.org/3/library/typing.html#typing.no_type_check
+        /// [#13824]: https://github.com/astral-sh/ruff/issues/13824
         const NO_TYPE_CHECK = 1 << 26;
 
         /// The context is in any type annotation.

From 530ddd2c10a6c3487f46d4b79d6338fdfb01dfca Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 11:32:04 -0500
Subject: [PATCH 04/13] use contains instead of manual check

---
 crates/ruff_linter/src/checkers/ast/mod.rs | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index 773ee3de3381b..f927cbc7fc691 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -1858,7 +1858,11 @@ impl<'a> Checker<'a> {
 
     /// Visit an [`Expr`], and treat it as a type definition.
     fn visit_type_definition(&mut self, expr: &'a Expr) {
-        if !(self.semantic.flags & SemanticModelFlags::NO_TYPE_CHECK).is_empty() {
+        if self
+            .semantic
+            .flags
+            .contains(SemanticModelFlags::NO_TYPE_CHECK)
+        {
             return;
         }
         let snapshot = self.semantic.flags;

From 10b2cacecdd22dc9c714dc6922fb28032ea0ec17 Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 11:45:53 -0500
Subject: [PATCH 05/13] switch to snapshot test

---
 .../test/fixtures/pyflakes/{F722.py => F722_0.py}    |  0
 .../resources/test/fixtures/pyflakes/F722_1.py       | 12 ++++++++++++
 .../resources/test/fixtures/pyflakes/F821_30.py      | 12 ++++++++++++
 crates/ruff_linter/src/rules/pyflakes/mod.rs         |  4 +++-
 ...ter__rules__pyflakes__tests__F722_F722_0.py.snap} |  4 ++--
 ...nter__rules__pyflakes__tests__F722_F722_1.py.snap |  5 +++++
 ...ter__rules__pyflakes__tests__F821_F821_30.py.snap |  5 +++++
 7 files changed, 39 insertions(+), 3 deletions(-)
 rename crates/ruff_linter/resources/test/fixtures/pyflakes/{F722.py => F722_0.py} (100%)
 create mode 100644 crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
 create mode 100644 crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
 rename crates/ruff_linter/src/rules/pyflakes/snapshots/{ruff_linter__rules__pyflakes__tests__F722_F722.py.snap => ruff_linter__rules__pyflakes__tests__F722_F722_0.py.snap} (63%)
 create mode 100644 crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap
 create mode 100644 crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap

diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_0.py
similarity index 100%
rename from crates/ruff_linter/resources/test/fixtures/pyflakes/F722.py
rename to crates/ruff_linter/resources/test/fixtures/pyflakes/F722_0.py
diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
new file mode 100644
index 0000000000000..88e2f8a585eaa
--- /dev/null
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
@@ -0,0 +1,12 @@
+"""Regression test for #13824.
+
+Don't report an error when the function being annotated has the
+`@no_type_check` decorator.
+"""
+
+from typing import no_type_check
+
+
+@no_type_check
+def f(arg: "this isn't python") -> "this isn't python either":
+    pass
diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
new file mode 100644
index 0000000000000..260181fccbe17
--- /dev/null
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
@@ -0,0 +1,12 @@
+"""Regression test for #13824.
+
+Don't report an error when the function being annotated has the
+`@no_type_check` decorator.
+"""
+
+from typing import no_type_check
+
+
+@no_type_check
+def f(arg: "A") -> "R":
+    pass
diff --git a/crates/ruff_linter/src/rules/pyflakes/mod.rs b/crates/ruff_linter/src/rules/pyflakes/mod.rs
index 519ef04036d69..e7de2c43a7b97 100644
--- a/crates/ruff_linter/src/rules/pyflakes/mod.rs
+++ b/crates/ruff_linter/src/rules/pyflakes/mod.rs
@@ -94,7 +94,8 @@ mod tests {
     #[test_case(Rule::YieldOutsideFunction, Path::new("F704.py"))]
     #[test_case(Rule::ReturnOutsideFunction, Path::new("F706.py"))]
     #[test_case(Rule::DefaultExceptNotLast, Path::new("F707.py"))]
-    #[test_case(Rule::ForwardAnnotationSyntaxError, Path::new("F722.py"))]
+    #[test_case(Rule::ForwardAnnotationSyntaxError, Path::new("F722_0.py"))]
+    #[test_case(Rule::ForwardAnnotationSyntaxError, Path::new("F722_1.py"))]
     #[test_case(Rule::RedefinedWhileUnused, Path::new("F811_0.py"))]
     #[test_case(Rule::RedefinedWhileUnused, Path::new("F811_1.py"))]
     #[test_case(Rule::RedefinedWhileUnused, Path::new("F811_2.py"))]
@@ -159,6 +160,7 @@ mod tests {
     #[test_case(Rule::UndefinedName, Path::new("F821_26.pyi"))]
     #[test_case(Rule::UndefinedName, Path::new("F821_27.py"))]
     #[test_case(Rule::UndefinedName, Path::new("F821_28.py"))]
+    #[test_case(Rule::UndefinedName, Path::new("F821_30.py"))]
     #[test_case(Rule::UndefinedExport, Path::new("F822_0.py"))]
     #[test_case(Rule::UndefinedExport, Path::new("F822_0.pyi"))]
     #[test_case(Rule::UndefinedExport, Path::new("F822_1.py"))]
diff --git a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722.py.snap b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_0.py.snap
similarity index 63%
rename from crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722.py.snap
rename to crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_0.py.snap
index 3a41c4a06203c..0e45ac706c607 100644
--- a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722.py.snap
+++ b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_0.py.snap
@@ -2,14 +2,14 @@
 source: crates/ruff_linter/src/rules/pyflakes/mod.rs
 snapshot_kind: text
 ---
-F722.py:9:12: F722 Syntax error in forward annotation: `///`
+F722_0.py:9:12: F722 Syntax error in forward annotation: `///`
    |
  9 | def g() -> "///":
    |            ^^^^^ F722
 10 |     pass
    |
 
-F722.py:13:4: F722 Syntax error in forward annotation: `List[int]☃`
+F722_0.py:13:4: F722 Syntax error in forward annotation: `List[int]☃`
    |
 13 | X: """List[int]"""'☃' = []
    |    ^^^^^^^^^^^^^^^^^^ F722
diff --git a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap
new file mode 100644
index 0000000000000..a487e4ddb80cf
--- /dev/null
+++ b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap
@@ -0,0 +1,5 @@
+---
+source: crates/ruff_linter/src/rules/pyflakes/mod.rs
+snapshot_kind: text
+---
+
diff --git a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap
new file mode 100644
index 0000000000000..a487e4ddb80cf
--- /dev/null
+++ b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap
@@ -0,0 +1,5 @@
+---
+source: crates/ruff_linter/src/rules/pyflakes/mod.rs
+snapshot_kind: text
+---
+

From 3fac5c5442378f01e79208bae079f09ed1b6065f Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 11:50:12 -0500
Subject: [PATCH 06/13] Revert "add test case from #13824"

This reverts commit 9aa49139392f2db134adc9cfe15852f55c30b38c.
---
 crates/ruff_linter/src/rules/pyflakes/mod.rs | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/crates/ruff_linter/src/rules/pyflakes/mod.rs b/crates/ruff_linter/src/rules/pyflakes/mod.rs
index e7de2c43a7b97..7fb0f32673a8d 100644
--- a/crates/ruff_linter/src/rules/pyflakes/mod.rs
+++ b/crates/ruff_linter/src/rules/pyflakes/mod.rs
@@ -4223,22 +4223,4 @@ lambda: fu
             &[],
         );
     }
-
-    #[test]
-    fn no_type_check_function() {
-        flakes(
-            r#"
-            from typing import no_type_check
-
-            @no_type_check
-            def f821(arg: "A") -> "R":
-                pass
-
-            @no_type_check
-            def f722(arg: "this isn't python") -> "this isn't python either":
-                pass
-        "#,
-            &[],
-        );
-    }
 }

From 01f29a7054cb3a4f53c24ffae617d824b6ac7854 Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 12:04:29 -0500
Subject: [PATCH 07/13] add failing tests for classes where no_type_check is
 also valid

---
 .../ruff_linter/resources/test/fixtures/pyflakes/F722_1.py  | 6 ++++++
 .../ruff_linter/resources/test/fixtures/pyflakes/F821_30.py | 6 ++++++
 2 files changed, 12 insertions(+)

diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
index 88e2f8a585eaa..c093290e5d328 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
@@ -10,3 +10,9 @@
 @no_type_check
 def f(arg: "this isn't python") -> "this isn't python either":
     pass
+
+
+@no_type_check
+class C:
+    def f(arg: "this isn't python") -> "this isn't python either":
+        pass
diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
index 260181fccbe17..7315b043c3da3 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
@@ -10,3 +10,9 @@
 @no_type_check
 def f(arg: "A") -> "R":
     pass
+
+
+@no_type_check
+class C:
+    def f(self, arg: "B") -> "S":
+        pass

From 06c1655c8f7ff9eab3895f65d92b6f39389918de Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 12:07:35 -0500
Subject: [PATCH 08/13] move no_type_check check into visit_decorator

---
 crates/ruff_linter/src/checkers/ast/mod.rs | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index f927cbc7fc691..01b2440d7d4b1 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -723,13 +723,6 @@ impl<'a> Visitor<'a> for Checker<'a> {
                 // Visit the decorators and arguments, but avoid the body, which will be
                 // deferred.
                 for decorator in decorator_list {
-                    if decorator
-                        .expression
-                        .as_name_expr()
-                        .is_some_and(|name| name.id.as_str() == "no_type_check")
-                    {
-                        self.semantic.flags |= SemanticModelFlags::NO_TYPE_CHECK;
-                    }
                     self.visit_decorator(decorator);
                 }
 
@@ -1067,6 +1060,17 @@ impl<'a> Visitor<'a> for Checker<'a> {
         self.semantic.flags = flags_snapshot;
     }
 
+    fn visit_decorator(&mut self, decorator: &'a ruff_python_ast::Decorator) {
+        if decorator
+            .expression
+            .as_name_expr()
+            .is_some_and(|name| name.id.as_str() == "no_type_check")
+        {
+            self.semantic.flags |= SemanticModelFlags::NO_TYPE_CHECK;
+        }
+        visitor::walk_decorator(self, decorator);
+    }
+
     fn visit_expr(&mut self, expr: &'a Expr) {
         // Step 0: Pre-processing
         if self.source_type.is_stub()

From b367082642fb881515042b62d3de316830c3fa0b Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 12:16:34 -0500
Subject: [PATCH 09/13] add and use SemanticModel::in_no_type_check

---
 crates/ruff_linter/src/checkers/ast/mod.rs | 6 +-----
 crates/ruff_python_semantic/src/model.rs   | 5 +++++
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index 01b2440d7d4b1..077261d203b88 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -1862,11 +1862,7 @@ impl<'a> Checker<'a> {
 
     /// Visit an [`Expr`], and treat it as a type definition.
     fn visit_type_definition(&mut self, expr: &'a Expr) {
-        if self
-            .semantic
-            .flags
-            .contains(SemanticModelFlags::NO_TYPE_CHECK)
-        {
+        if self.semantic.in_no_type_check() {
             return;
         }
         let snapshot = self.semantic.flags;
diff --git a/crates/ruff_python_semantic/src/model.rs b/crates/ruff_python_semantic/src/model.rs
index 0eabf141d562d..d2d4907881d81 100644
--- a/crates/ruff_python_semantic/src/model.rs
+++ b/crates/ruff_python_semantic/src/model.rs
@@ -1584,6 +1584,11 @@ impl<'a> SemanticModel<'a> {
         self.flags.intersects(SemanticModelFlags::ANNOTATION)
     }
 
+    /// Return `true` if the model is in a `@no_type_check` context.
+    pub const fn in_no_type_check(&self) -> bool {
+        self.flags.intersects(SemanticModelFlags::NO_TYPE_CHECK)
+    }
+
     /// Return `true` if the model is in a typing-only type annotation.
     pub const fn in_typing_only_annotation(&self) -> bool {
         self.flags

From 615b4b8732db8aaf89452e374b1cb6db165875ec Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 12:42:13 -0500
Subject: [PATCH 10/13] ensure no_type_check propagates into function bodies

---
 crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py | 4 ++--
 .../ruff_linter/resources/test/fixtures/pyflakes/F821_30.py   | 4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
index c093290e5d328..5d0ca18cbc634 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
@@ -9,10 +9,10 @@
 
 @no_type_check
 def f(arg: "this isn't python") -> "this isn't python either":
-    pass
+    x: "this also isn't python" = 0
 
 
 @no_type_check
 class C:
     def f(arg: "this isn't python") -> "this isn't python either":
-        pass
+        x: "this also isn't python" = 1
diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
index 7315b043c3da3..fffb87b6a33cb 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
@@ -9,10 +9,10 @@
 
 @no_type_check
 def f(arg: "A") -> "R":
-    pass
+    x: "A" = 1
 
 
 @no_type_check
 class C:
     def f(self, arg: "B") -> "S":
-        pass
+        x: "B" = 1

From a60b747c76b325784ac1fac29598fe5c01e97300 Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 12:58:33 -0500
Subject: [PATCH 11/13] make sure typing.no_type_check works too

---
 .../ruff_linter/resources/test/fixtures/pyflakes/F821_30.py | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
index fffb87b6a33cb..d0e19594f8330 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
@@ -4,15 +4,15 @@
 `@no_type_check` decorator.
 """
 
-from typing import no_type_check
+import typing
 
 
-@no_type_check
+@typing.no_type_check
 def f(arg: "A") -> "R":
     x: "A" = 1
 
 
-@no_type_check
+@typing.no_type_check
 class C:
     def f(self, arg: "B") -> "S":
         x: "B" = 1

From 350f6e3121ccea05b1396a8434b35025eb995327 Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 12:55:18 -0500
Subject: [PATCH 12/13] use `match_typing_expr`

---
 crates/ruff_linter/src/checkers/ast/mod.rs | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index 077261d203b88..b33e0fcfaf55b 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -1061,10 +1061,9 @@ impl<'a> Visitor<'a> for Checker<'a> {
     }
 
     fn visit_decorator(&mut self, decorator: &'a ruff_python_ast::Decorator) {
-        if decorator
-            .expression
-            .as_name_expr()
-            .is_some_and(|name| name.id.as_str() == "no_type_check")
+        if self
+            .semantic
+            .match_typing_expr(&decorator.expression, "no_type_check")
         {
             self.semantic.flags |= SemanticModelFlags::NO_TYPE_CHECK;
         }

From 1d5ee646f6ad0aaf352c0518f870f7504e12b5df Mon Sep 17 00:00:00 2001
From: Brent Westbrook <brentrwestbrook@gmail.com>
Date: Tue, 26 Nov 2024 13:45:30 -0500
Subject: [PATCH 13/13] ignore `@no_type_check` for classes

---
 .../test/fixtures/pyflakes/F722_1.py          |  3 +++
 .../test/fixtures/pyflakes/F821_30.py         |  3 +++
 crates/ruff_linter/src/checkers/ast/mod.rs    | 16 +++++--------
 ...ules__pyflakes__tests__F722_F722_1.py.snap | 24 +++++++++++++++++++
 ...les__pyflakes__tests__F821_F821_30.py.snap | 24 +++++++++++++++++++
 5 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
index 5d0ca18cbc634..203aa2b3ef269 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F722_1.py
@@ -2,6 +2,9 @@
 
 Don't report an error when the function being annotated has the
 `@no_type_check` decorator.
+
+However, we still want to ignore this annotation on classes. See
+https://github.com/python/typing/pull/1615/files and the discussion on #14615.
 """
 
 from typing import no_type_check
diff --git a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
index d0e19594f8330..d0c1b812b460e 100644
--- a/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
+++ b/crates/ruff_linter/resources/test/fixtures/pyflakes/F821_30.py
@@ -2,6 +2,9 @@
 
 Don't report an error when the function being annotated has the
 `@no_type_check` decorator.
+
+However, we still want to ignore this annotation on classes. See
+https://github.com/python/typing/pull/1615/files and the discussion on #14615.
 """
 
 import typing
diff --git a/crates/ruff_linter/src/checkers/ast/mod.rs b/crates/ruff_linter/src/checkers/ast/mod.rs
index b33e0fcfaf55b..97154f4fccee5 100644
--- a/crates/ruff_linter/src/checkers/ast/mod.rs
+++ b/crates/ruff_linter/src/checkers/ast/mod.rs
@@ -723,6 +723,12 @@ impl<'a> Visitor<'a> for Checker<'a> {
                 // Visit the decorators and arguments, but avoid the body, which will be
                 // deferred.
                 for decorator in decorator_list {
+                    if self
+                        .semantic
+                        .match_typing_expr(&decorator.expression, "no_type_check")
+                    {
+                        self.semantic.flags |= SemanticModelFlags::NO_TYPE_CHECK;
+                    }
                     self.visit_decorator(decorator);
                 }
 
@@ -1060,16 +1066,6 @@ impl<'a> Visitor<'a> for Checker<'a> {
         self.semantic.flags = flags_snapshot;
     }
 
-    fn visit_decorator(&mut self, decorator: &'a ruff_python_ast::Decorator) {
-        if self
-            .semantic
-            .match_typing_expr(&decorator.expression, "no_type_check")
-        {
-            self.semantic.flags |= SemanticModelFlags::NO_TYPE_CHECK;
-        }
-        visitor::walk_decorator(self, decorator);
-    }
-
     fn visit_expr(&mut self, expr: &'a Expr) {
         // Step 0: Pre-processing
         if self.source_type.is_stub()
diff --git a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap
index a487e4ddb80cf..f79147a188710 100644
--- a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap
+++ b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F722_F722_1.py.snap
@@ -2,4 +2,28 @@
 source: crates/ruff_linter/src/rules/pyflakes/mod.rs
 snapshot_kind: text
 ---
+F722_1.py:20:16: F722 Syntax error in forward annotation: `this isn't python`
+   |
+18 | @no_type_check
+19 | class C:
+20 |     def f(arg: "this isn't python") -> "this isn't python either":
+   |                ^^^^^^^^^^^^^^^^^^^ F722
+21 |         x: "this also isn't python" = 1
+   |
 
+F722_1.py:20:40: F722 Syntax error in forward annotation: `this isn't python either`
+   |
+18 | @no_type_check
+19 | class C:
+20 |     def f(arg: "this isn't python") -> "this isn't python either":
+   |                                        ^^^^^^^^^^^^^^^^^^^^^^^^^^ F722
+21 |         x: "this also isn't python" = 1
+   |
+
+F722_1.py:21:12: F722 Syntax error in forward annotation: `this also isn't python`
+   |
+19 | class C:
+20 |     def f(arg: "this isn't python") -> "this isn't python either":
+21 |         x: "this also isn't python" = 1
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^ F722
+   |
diff --git a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap
index a487e4ddb80cf..65b4a6cb293c7 100644
--- a/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap
+++ b/crates/ruff_linter/src/rules/pyflakes/snapshots/ruff_linter__rules__pyflakes__tests__F821_F821_30.py.snap
@@ -2,4 +2,28 @@
 source: crates/ruff_linter/src/rules/pyflakes/mod.rs
 snapshot_kind: text
 ---
+F821_30.py:20:23: F821 Undefined name `B`
+   |
+18 | @typing.no_type_check
+19 | class C:
+20 |     def f(self, arg: "B") -> "S":
+   |                       ^ F821
+21 |         x: "B" = 1
+   |
 
+F821_30.py:20:31: F821 Undefined name `S`
+   |
+18 | @typing.no_type_check
+19 | class C:
+20 |     def f(self, arg: "B") -> "S":
+   |                               ^ F821
+21 |         x: "B" = 1
+   |
+
+F821_30.py:21:13: F821 Undefined name `B`
+   |
+19 | class C:
+20 |     def f(self, arg: "B") -> "S":
+21 |         x: "B" = 1
+   |             ^ F821
+   |