gh-151955: Allow more ParamSpec and TypeVarTuple bounds (#151956)

JelleZijlstra · web-flow · commit 0fb82b46df7b · 2026-06-24T09:10:10.000-07:00
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
@@ -1316,6 +1316,11 @@ def test_infer_variance(self):
     def test_bound(self):
         Ts_bound = TypeVarTuple('Ts_bound', bound=int)
         self.assertIs(Ts_bound.__bound__, int)
+        Ts_tuple_bound = TypeVarTuple('Ts_tuple_bound', bound=(int, str))
+        self.assertEqual(Ts_tuple_bound.__bound__, (int, str))
+        obj = object()
+        Ts_object = TypeVarTuple('Ts_object', bound=obj)
+        self.assertIs(Ts_object.__bound__, obj)
         Ts_no_bound = TypeVarTuple('Ts_no_bound')
         self.assertIsNone(Ts_no_bound.__bound__)
 
@@ -10534,6 +10539,17 @@ def test_paramspec_in_nested_generics(self):
         self.assertEqual(G2[[int, str], float], list[C])
         self.assertEqual(G3[[int, str], float], list[C] | int)
 
+    def test_paramspec_bound(self):
+        P = ParamSpec('P', bound=[int, str])
+        self.assertEqual(P.__bound__, [int, str])
+        P2 = ParamSpec('P2', bound=(int, str))
+        self.assertEqual(P2.__bound__, (int, str))
+        obj = object()
+        P3 = ParamSpec('P3', bound=obj)
+        self.assertIs(P3.__bound__, obj)
+        P4 = ParamSpec('P4')
+        self.assertIs(P4.__bound__, None)
+
     def test_paramspec_gets_copied(self):
         # bpo-46581
         P = ParamSpec('P')
diff --git a/Misc/NEWS.d/next/Library/2026-06-22-18-01-00.gh-issue-151955.6u5iwm.rst b/Misc/NEWS.d/next/Library/2026-06-22-18-01-00.gh-issue-151955.6u5iwm.rst
@@ -0,0 +1,2 @@
+Allow more types to be used in the ``bound`` argument to
+:class:`typing.ParamSpec` and :class:`typing.TypeVarTuple`.
diff --git a/Objects/typevarobject.c b/Objects/typevarobject.c
@@ -1340,20 +1340,12 @@ paramspec_new_impl(PyTypeObject *type, PyObject *name, PyObject *bound,
         PyErr_SetString(PyExc_ValueError, "Variance cannot be specified with infer_variance.");
         return NULL;
     }
-    if (bound != NULL) {
-        bound = type_check(bound, "Bound must be a type.");
-        if (bound == NULL) {
-            return NULL;
-        }
-    }
     PyObject *module = caller();
     if (module == NULL) {
-        Py_XDECREF(bound);
         return NULL;
     }
     PyObject *ps = (PyObject *)paramspec_alloc(
         name, bound, default_value, covariant, contravariant, infer_variance, module);
-    Py_XDECREF(bound);
     Py_DECREF(module);
     return ps;
 }
@@ -1634,23 +1626,12 @@ typevartuple_impl(PyTypeObject *type, PyObject *name, PyObject *bound,
         PyErr_SetString(PyExc_ValueError, "Variance cannot be specified with infer_variance.");
         return NULL;
     }
-    if (Py_IsNone(bound)) {
-        bound = NULL;
-    }
-    if (bound != NULL) {
-        bound = type_check(bound, "Bound must be a type.");
-        if (bound == NULL) {
-            return NULL;
-        }
-    }
     PyObject *module = caller();
     if (module == NULL) {
-        Py_XDECREF(bound);
         return NULL;
     }
     PyObject *result = (PyObject *)typevartuple_alloc(
         name, bound, default_value, covariant, contravariant, infer_variance, module);
-    Py_XDECREF(bound);
     Py_DECREF(module);
     return result;
 }

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Allow more types to be used in the ``bound`` argument to
	`2`	+:class:`typing.ParamSpec` and :class:`typing.TypeVarTuple`.