More bug 460020. When I is a subclass of int, disable the +I(whatever),

I(0) << whatever, I(0) >> whatever, I(whatever) << 0 and I(whatever) >> 0
optimizations.

Lib/test/test_descr.py

@@ -1366,6 +1366,11 @@ def inherits():
     a = hexint(12345)
     verify(int(a) == 12345)
     verify(int(a).__class__ is int)
+    verify((+a).__class__ is int)
+    verify((a >> 0).__class__ is int)
+    verify((a << 0).__class__ is int)
+    verify((hexint(0) << 12).__class__ is int)
+    verify((hexint(0) >> 12).__class__ is int)
 
     class octlong(long):
         __slots__ = []

Objects/intobject.c

@@ -681,8 +681,12 @@ int_neg(PyIntObject *v)
 static PyObject *
 int_pos(PyIntObject *v)
 {
-	Py_INCREF(v);
-	return (PyObject *)v;
+	if (PyInt_CheckExact(v)) {
+		Py_INCREF(v);
+		return (PyObject *)v;
+	}
+	else
+		return PyInt_FromLong(v->ob_ival);
 }
 
 static PyObject *
@@ -716,10 +720,8 @@ int_lshift(PyIntObject *v, PyIntObject *w)
 		PyErr_SetString(PyExc_ValueError, "negative shift count");
 		return NULL;
 	}
-	if (a == 0 || b == 0) {
-		Py_INCREF(v);
-		return (PyObject *) v;
-	}
+	if (a == 0 || b == 0)
+		return int_pos(v);
 	if (b >= LONG_BIT) {
 		return PyInt_FromLong(0L);
 	}
@@ -737,10 +739,8 @@ int_rshift(PyIntObject *v, PyIntObject *w)
 		PyErr_SetString(PyExc_ValueError, "negative shift count");
 		return NULL;
 	}
-	if (a == 0 || b == 0) {
-		Py_INCREF(v);
-		return (PyObject *) v;
-	}
+	if (a == 0 || b == 0)
+		return int_pos(v);
 	if (b >= LONG_BIT) {
 		if (a < 0)
 			a = -1;