diff --git a/mypy/stubgen.py b/mypy/stubgen.py
--- a/mypy/stubgen.py
+++ b/mypy/stubgen.py
@@ -95,6 +95,7 @@
     MemberExpr,
     MypyFile,
     NameExpr,
+    OpExpr,
     OverloadedFuncDef,
     Statement,
     StrExpr,
@@ -402,6 +403,9 @@ def visit_list_expr(self, node: ListExpr) -> str:
     def visit_ellipsis(self, node: EllipsisExpr) -> str:
         return "..."
 
+    def visit_op_expr(self, o: OpExpr) -> str:
+        return f"{o.left.accept(self)} {o.op} {o.right.accept(self)}"
+
 
 class ImportTracker:
     """Record necessary imports during stub generation."""

diff --git a/test-data/unit/stubgen.test b/test-data/unit/stubgen.test
--- a/test-data/unit/stubgen.test
+++ b/test-data/unit/stubgen.test
@@ -2734,3 +2734,12 @@ class Some:
     def __int__(self) -> int: ...
     def __float__(self) -> float: ...
     def __index__(self) -> int: ...
+
+
+[case testTypeVarPEP604Bound]
+from typing import TypeVar
+T = TypeVar("T", bound=str | None)
+[out]
+from typing import TypeVar
+
+T = TypeVar('T', bound=str | None)

Stubgen crashes on new Python 3.10 union syntax
<!--
  Use this form only if mypy reports an "INTERNAL ERROR" and/or gives a traceback.
  Please include the traceback and all other messages below (use `mypy --show-traceback`).
-->

**Crash Report**

It works in some cases e.g. with `cast()` function but here with `TypeVar` it crashes.

Mypy accepts this file with no errors.

**Traceback**

```
  File "mypy/stubgen.py", line 1858, in main
  File "mypy/stubgen.py", line 1701, in generate_stubs
  File "mypy/stubgen.py", line 1643, in generate_stub_from_ast
  File "mypy/nodes.py", line 373, in accept
  File "mypy/stubgen.py", line 643, in visit_mypy_file
  File "mypy/traverser.py", line 114, in visit_mypy_file
  File "mypy/nodes.py", line 1301, in accept
  File "mypy/stubgen.py", line 1006, in visit_assignment_stmt
  File "mypy/stubgen.py", line 1117, in process_typealias
  File "mypy/nodes.py", line 1841, in accept
  File "mypy/stubgen.py", line 362, in visit_call_expr
TypeError: str object expected; got None
```

**To Reproduce**

```python3
from __future__ import annotations

from typing import TypeVar

T = TypeVar("T", bound=str | None)
```

**Your Environment**

<!-- Include as many relevant details about the environment you experienced the bug in -->

- Mypy version used: 0.991
- Mypy command-line flags: `stubgen test.py`
- Mypy configuration options from `mypy.ini` (and other config files):
- Python version used: 3.10.9
- Operating system and version: macOS

<!--
You can freely edit this text, please remove all the lines
you believe are unnecessary.
-->


mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSpecialInternalVar mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testMultipleVariable mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testPreserveVarAnnotation mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testEmptyFile mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testClassVariable mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testPreserveVarAnnotationWithoutQuotes mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testBaseClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSingleFunction mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testInitTypeAnnotationPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testVarArgs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDecoratedFunction mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTwoFunctions mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSelfAssignment mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testKwVarArgs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testMultipleAssignment mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDefaultArgInt mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSelfAndClassBodyAssignment mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDefaultArgNone mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testMultipleAssignmentAnnotated mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testVarArgsWithKwVarArgs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testEmptyClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDefaultArgBool mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testMultipleAssignment2 mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSkipPrivateFunction mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDefaultArgStr mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testKeywordOnlyArg mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludePrivateFunction mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testVariable mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDefaultArgBytes mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testProperty mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSkipPrivateMethod mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDefaultArgFloat mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotatedVariable mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludePrivateMethod mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testStaticMethod mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDefaultArgOther mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotatedVariableGeneric mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSkipPrivateVar mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testClassMethod mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotatedVariableOldSyntax mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludePrivateVar mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testPreserveFunctionAnnotation mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIfMainCheck mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotatedVariableNone mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNoSpacesBetweenEmptyClasses mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImportStar mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testPreserveFunctionAnnotationWithArgs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotatedVariableNoneOldSyntax mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExceptionBaseClasses mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSkipPrivateStaticAndClassMethod mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedtupleAltSyntaxFieldsTuples mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludePrivateStaticAndClassMethod mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testOmitSomeSpecialMethods mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDynamicNamedTuple mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedtuple mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testArbitraryBaseClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testEmptyNamedtuple mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportModule_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testArbitraryBaseClass2 mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedtupleAltSyntax mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testOmitDefsNotInAll_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testUnqualifiedArbitraryBaseClassWithNoDef mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedtupleAltSyntaxUsingComma mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testUnqualifiedArbitraryBaseClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportModule2_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedtupleAltSyntaxUsingMultipleCommas mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testUnqualifiedArbitraryBaseClassWithImportAs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedtupleWithUnderscore mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testGenericClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedtupleBaseClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testObjectBaseClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportModuleAs_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testEmptyLines mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testInferOptionalOnlyFunc mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNestedClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotationImportsFrom mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportViaRelativeImport mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportModuleInPackage_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotationImports mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportViaRelativePackageImport mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNoExportViaRelativeImport mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotationImports2 mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testRelativeImportAndBase mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAnnotationFwRefs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportPackageOfAModule_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDuplicateDef mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTypeVarPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testRelativeImportAll mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAsyncAwait_fast_parser mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTypeVarArgsPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTypeAliasPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTypeVarNamedArgsPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDeepTypeAliasPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAliasExceptions mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCommentForUndefinedName_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFunctionNoReturnInfersReturnNone mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDeepGenericTypeAliasPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIgnoreSlots mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFunctionReturnNoReturnType mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testEllipsisAliasPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFunctionEllipsisInfersReturnNone mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSkipPrivateProperty mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCallableAliasPreserved mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFunctionYields mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludePrivateProperty mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAliasPullsImport mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFunctionYieldsNone mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testGeneratorAlreadyDefined mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCallable mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAliasOnlyToplevel mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportAsyncioAsA mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAwaitDef mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineFromAsyncioImportCoroutine mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportAsyncioCoroutinesAsC mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineFromAsyncioCoroutinesImportCoroutine mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportAsyncio mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportAsyncioCoroutinesSubAsA mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineFromTypesImportCoroutine mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportAsyncioCoroutines mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportTypesAsT mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineFromAsyncioImportCoroutineAsC mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportAsyncioCoroutinesSub mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineFromAsyncioCoroutinesImportCoroutineAsC mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineImportTypes mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCoroutineFromTypesImportCoroutineAsC mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAbstractMethodMemberExpr mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAbstractMethodMemberExpr2 mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testOmitDefsNotInAll_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testVarDefsNotInAll_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludeClassNotInAll_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAllAndClass_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testSkipMultiplePrivateDefs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludeMultiplePrivateDefs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testIncludeFromImportIfInAll_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExplicitAnyArg mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExplicitReturnedAny mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testPlacementOfDecorators mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testMisplacedTypeComment mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNestedClass_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testModuleAlias_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testABCMeta_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testInvalidNumberOfArgsInAnnotation mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFunctionPartiallyAnnotated mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAbstractProperty2_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testBadAliasNested_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testConditionalImportAll_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFunctionAlias_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAbstractProperty3_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testClassWithNameIncompleteOrOptional mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportedNameImported mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testVendoredSix mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testVendoredPackage mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTestFiles mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCrossModuleClass_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTestFiles_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testVerboseFlag mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImportedModuleExits_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImportedModuleHardExits_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImportedModuleHardExits2_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImportedModuleHardExits3_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImportedModuleHardExits4_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportInternalImportsByDefault mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNoExportOfInternalImportsIfAll_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportInternalImportsByDefaultFromUnderscorePackage mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testDisableExportOfInternalImports mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportInternalImportsByDefaultUsingRelativeImport mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportInternalImportsByDefaultSkipPrivate mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testExportInternalImportsByDefaultIncludePrivate mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testHideDunderModuleAttributes mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testHideDunderModuleAttributesWithAll_import mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCannotCalculateMRO_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testPrivateAliasesIncluded_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testCrossModuleFunction_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testUnreachableCode_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAttrsClass_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNamedTupleInClass mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImport_overwrites_directWithAlias_from mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImport_overwrites_directWithAlias_fromWithAlias mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImports_overwrites_direct_from mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImports_overwrites_direct_fromWithAlias mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImports_overwrites_from_directWithAlias mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImports_overwrites_fromWithAlias_direct mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImports_direct mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testOverload_fromTypingImport mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testOverload_fromTypingExtensionsImport mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testOverload_importTyping mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testOverload_importTypingAs mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFinalWrapped_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAbstractProperty1_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImports_directImportsMixed mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNonDefaultKeywordOnlyArgAfterAsterisk mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNestedGenerator mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testKnownMagicMethodsReturnTypes mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testPrivateAliasesExcluded_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testImports_directImportsWithAlias mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testProtocol_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testFinalInvalid_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testProtocolAbstractMethod_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testNoFunctionNested_semanal mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testAbstractMethodNameExpr
mypy/test/teststubgen.py::StubgenPythonSuite::stubgen.test::testTypeVarPEP604Bound