Merge pull request #839 from asottile/typevar-bounds-563

support PEP 563 rewrites for 3.12+ TypeVar bounds

pyupgrade/_plugins/typing_pep563.py

@@ -176,3 +176,16 @@ def visit_AnnAssign(
     if not _supported_version(state):
         return
     yield from _replace_string_literal(node.annotation)
+
+
+if sys.version_info >= (3, 12):  # pragma: >=3.12 cover
+    @register(ast.TypeVar)
+    def visit_TypeVar(
+            state: State,
+            node: ast.TypeVar,
+            parent: ast.AST,
+    ) -> Iterable[tuple[Offset, TokenFunc]]:
+        if not _supported_version(state):
+            return
+        if node.bound is not None:
+            yield from _replace_string_literal(node.bound)

tests/features/typing_pep563_test.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import sys
+
 import pytest
 
 from pyupgrade._data import Settings
@@ -54,6 +56,15 @@
             'x: Annotated[1:2] = ...\n',
             id='Annotated with invalid slice',
         ),
+        pytest.param(
+            'def f[X: "int"](x: X) -> X: return x\n',
+            id='TypeVar quoted bound but no __future__ annotations',
+        ),
+        pytest.param(
+            'from __future__ import annotations\n'
+            'def f[X](x: X) -> X: return x\n',
+            id='TypeVar without bound',
+        ),
     ),
 )
 def test_fix_typing_pep563_noop(s):
@@ -363,3 +374,19 @@ def test_fix_typing_pep563_noop(s):
 def test_fix_typing_pep563(s, expected):
     ret = _fix_plugins(s, settings=Settings(min_version=(3, 7)))
     assert ret == expected
+
+
+@pytest.mark.xfail(sys.version_info < (3, 12), reason='3.12+ syntax')
+def test_typevar_bound():
+    src = '''\
+from __future__ import annotations
+def f[T: "int"](t: T) -> T:
+    return t
+'''
+    expected = '''\
+from __future__ import annotations
+def f[T: int](t: T) -> T:
+    return t
+'''
+    ret = _fix_plugins(src, settings=Settings())
+    assert ret == expected