fix: Fixes handling of recursive type aliases

.github/workflows/testing.yml

@@ -38,7 +38,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        python-version: ["3.9", "3.10", "3.11", "3.12", "3.13", "3.14"]
+        python-version: ["3.10", "3.11", "3.12", "3.13", "3.14"]
     steps:
       - uses: actions/checkout@v6
       - uses: actions/setup-python@v6

README.md

@@ -1,6 +1,6 @@
 [![Package version](https://img.shields.io/pypi/v/flake8-type-checking.svg)](https://pypi.org/project/flake8-type-checking/)
 [![Test status](https://github.com/snok/flake8-type-checking/actions/workflows/testing.yml/badge.svg)](https://github.com/snok/flake8-type-checking/actions/workflows/testing.yml)
-[![Supported Python versions](https://img.shields.io/badge/python-3.9%2B-blue)](https://pypi.org/project/flake8-type-checking/)
+[![Supported Python versions](https://img.shields.io/badge/python-3.10%2B-blue)](https://pypi.org/project/flake8-type-checking/)
 [![Checked with mypy](http://www.mypy-lang.org/static/mypy_badge.svg)](http://mypy-lang.org/)
 [![codecov](https://codecov.io/gh/snok/flake8-type-checking/graph/badge.svg?token=c0hqbAteWi)](https://codecov.io/gh/snok/flake8-type-checking)
 

flake8_type_checking/checker.py

@@ -1542,8 +1542,11 @@ def visit_AnnAssign(self, node: ast.AnnAssign) -> None:
             self.current_scope.symbols[node.target.id].append(
                 Symbol(
                     node.target.id,
-                    node.target.lineno,
-                    node.target.col_offset,
+                    # We use the end of the statement for the position of the symbol so
+                    # lexicographical lookups correctly only see the symbol after the end
+                    # of the statement.
+                    node.lineno if node.end_lineno is None else node.end_lineno,
+                    node.col_offset if node.end_col_offset is None else node.end_col_offset,
                     (
                         # AnnAssign can omit the RHS, in which case it's just a declaration
                         # and doesn't result in a variable that's available at runtime

pyproject.toml

@@ -17,7 +17,6 @@ classifiers = [
     'License :: OSI Approved :: BSD License',
     'Topic :: Software Development :: Quality Assurance',
     'Programming Language :: Python',
-    'Programming Language :: Python :: 3.9',
     'Programming Language :: Python :: 3.10',
     'Programming Language :: Python :: 3.11',
     'Programming Language :: Python :: 3.12',
@@ -30,21 +29,19 @@ classifiers = [
 "Releases" = "https://github.com/snok/flake8-type-checking/releases"
 
 [tool.poetry.dependencies]
-python = '>=3.9'
+python = '>=3.10'
 flake8 = '*'
 classify-imports = '*'
 
-[tool.poetry.dev-dependencies]
+[tool.poetry.plugins.'flake8.extension']
+TC = 'flake8_type_checking.plugin:Plugin'
+
+[tool.poetry.group.dev.dependencies]
 pytest = '*'
 ipython = '*'
 coverage = '*'
 pre-commit = '*'
 pytest-flake8-path = '*'
-
-[tool.poetry.plugins.'flake8.extension']
-TC = 'flake8_type_checking.plugin:Plugin'
-
-[tool.poetry.group.dev.dependencies]
 flake8-bugbear = "^24.10.31"
 
 [build-system]

tests/test_tc007.py

@@ -20,6 +20,8 @@
     ("if TYPE_CHECKING:\n\tfrom typing import Dict\nx: TypeAlias = 'Dict'", set()),
     ("if TYPE_CHECKING:\n\tfrom typing import Dict as d\nx: TypeAlias = 'd[int]'", set()),
     ('if TYPE_CHECKING:\n\tfrom typing import Dict\nx: TypeAlias = Dict[int]', {'3:15 ' + TC007.format(alias='Dict')}),
+    # recursive type aliases should trigger TC007
+    ('X: TypeAlias = Union[str, dict[str, X]]', {'1:36 ' + TC007.format(alias='X')}),
     # Regression test for issue #163
     (
         textwrap.dedent('''

tests/test_tc008.py

@@ -32,6 +32,8 @@
         "from __future__ import annotations\nif TYPE_CHECKING:\n\tfrom typing import Dict\nx: TypeAlias = Dict['int']",
         {'4:20 ' + TC008.format(alias='int')},
     ),
+    # recursive type aliases should not trigger TC008
+    ("X: TypeAlias = Union[str, dict[str, 'X']]", set()),
     (
         textwrap.dedent('''
         from __future__ import annotations
@@ -88,6 +90,24 @@ class X(Protocol):
         '''),
         set(),
     ),
+    (
+        # Regression test for issue #209
+        textwrap.dedent('''
+        from __future__ import annotations
+
+        from collections.abc import Mapping
+        from typing import TYPE_CHECKING, Union, TypeAlias
+
+        MyTypeAlias: TypeAlias = Union[
+            bool,
+            str,
+            int,
+            float,
+            Mapping[str, "MyTypeAlias"],
+        ]
+        '''),
+        set(),
+    ),
 ]
 
 if sys.version_info >= (3, 12):