[flake8-async] Fix in_async_context logic

crates/ruff_linter/resources/test/fixtures/flake8_async/ASYNC250.py

@@ -20,3 +20,10 @@ def foo():
 async def foo():
     builtins.input("testing")  # ASYNC250
     fake.input("whatever")  # Ok
+
+# Regression test for https://github.com/astral-sh/ruff/issues/23425
+import asyncio
+
+async def main() -> None:
+    input("sync") # should emit here
+    await asyncio.to_thread(lambda: input("async")) # but not here

crates/ruff_linter/src/checkers/ast/mod.rs

@@ -797,17 +797,7 @@ impl SemanticSyntaxContext for Checker<'_> {
     }
 
     fn in_async_context(&self) -> bool {
-        for scope in self.semantic.current_scopes() {
-            match scope.kind {
-                ScopeKind::Class(_) | ScopeKind::Lambda(_) => return false,
-                ScopeKind::Function(ast::StmtFunctionDef { is_async, .. }) => return *is_async,
-                ScopeKind::Generator { .. }
-                | ScopeKind::Module
-                | ScopeKind::Type
-                | ScopeKind::DunderClassCell => {}
-            }
-        }
-        false
+        self.semantic.in_async_context()
     }
 
     fn in_await_allowed_context(&self) -> bool {

crates/ruff_linter/src/rules/flake8_async/snapshots/ruff_linter__rules__flake8_async__tests__ASYNC250_ASYNC250.py.snap

@@ -27,3 +27,12 @@ ASYNC250 Blocking call to `input()` in async context
    |     ^^^^^^^^^^^^^^
 22 |     fake.input("whatever")  # Ok
    |
+
+ASYNC250 Blocking call to `input()` in async context
+  --> ASYNC250.py:28:5
+   |
+27 | async def main() -> None:
+28 |     input("sync") # should emit here
+   |     ^^^^^
+29 |     await asyncio.to_thread(lambda: input("async")) # but not here
+   |

crates/ruff_python_semantic/src/model.rs

@@ -1595,8 +1595,13 @@ impl<'a> SemanticModel<'a> {
     /// Return `true` if the model is in an async context.
     pub fn in_async_context(&self) -> bool {
         for scope in self.current_scopes() {
-            if let ScopeKind::Function(ast::StmtFunctionDef { is_async, .. }) = scope.kind {
-                return *is_async;
+            match scope.kind {
+                ScopeKind::Class(_) | ScopeKind::Lambda(_) => return false,
+                ScopeKind::Function(ast::StmtFunctionDef { is_async, .. }) => return *is_async,
+                ScopeKind::Generator { .. }
+                | ScopeKind::Module
+                | ScopeKind::Type
+                | ScopeKind::DunderClassCell => {}
             }
         }
         false