fix and add test

src/capi/object.cpp

@@ -569,23 +569,28 @@ extern "C" PyObject** _PyObject_GetDictPtr(PyObject* obj) noexcept {
     Py_ssize_t dictoffset;
     PyTypeObject* tp = Py_TYPE(obj);
 
-    dictoffset = tp->tp_dictoffset;
-    if (dictoffset == 0)
-        return NULL;
-    if (dictoffset < 0) {
-        Py_ssize_t tsize;
-        size_t size;
-
-        tsize = ((PyVarObject*)obj)->ob_size;
-        if (tsize < 0)
-            tsize = -tsize;
-        size = _PyObject_VAR_SIZE(tp, tsize);
-
-        dictoffset += (long)size;
-        assert(dictoffset > 0);
-        assert(dictoffset % SIZEOF_VOID_P == 0);
+    if (!tp->instancesHaveHCAttrs()) {
+        dictoffset = tp->tp_dictoffset;
+        if (dictoffset == 0)
+            return NULL;
+        if (dictoffset < 0) {
+            Py_ssize_t tsize;
+            size_t size;
+
+            tsize = ((PyVarObject*)obj)->ob_size;
+            if (tsize < 0)
+                tsize = -tsize;
+            size = _PyObject_VAR_SIZE(tp, tsize);
+
+            dictoffset += (long)size;
+            assert(dictoffset > 0);
+            assert(dictoffset % SIZEOF_VOID_P == 0);
+        }
+        return (PyObject**)((char*)obj + dictoffset);
+    } else {
+        fatalOrError(PyExc_NotImplementedError, "unimplemented for hcattrs");
+        return nullptr;
     }
-    return (PyObject**)((char*)obj + dictoffset);
 }
 
 /* These methods are used to control infinite recursion in repr, str, print,

test/tests/datetime_test.py

@@ -2,6 +2,16 @@
 # Doesn't test much of the functionality, but even importing the module is tough:
 
 import datetime
+
+def typeErrorTest(val):
+    try:
+        x = datetime.timedelta(43)
+        x // val
+    except TypeError as e:
+        return True
+    return False
+
+
 print repr(datetime.time())
 print datetime.datetime.__base__
 print repr(datetime.datetime(1, 2, 3))
@@ -11,3 +21,8 @@ print str(datetime.timedelta(0))
 datetime.datetime.now().now()
 
 print datetime.datetime(1924, 2, 3).strftime("%B %d, %Y - %X")
+
+a = 3
+b = 3.4
+assert not typeErrorTest(a)
+assert typeErrorTest(b)