Raise TypeError when _asdict() is callable but does not return a dict

1 files changed, 5 insertions, 0 deletions

diff --git a/simplejson/_speedups.c b/simplejson/_speedups.c
index ef0dc6b..6fefa99 100644
--- a/simplejson/_speedups.c
+++ b/simplejson/_speedups.c
@@ -2856,6 +2856,11 @@ encoder_listencode_obj(PyEncoderObject *s, JSON_Accu *rval, PyObject *obj, Py_ss
             newobj = PyObject_CallMethod(obj, "_asdict", NULL);
             if (newobj != NULL) {
                 if (!PyDict_Check(newobj)) {
+                    PyErr_Format(
+                        PyExc_TypeError,
+                        "_asdict() must return a dict, not %.80s",
+                        Py_TYPE(newobj)->tp_name
+                    );
                     Py_DECREF(newobj);
                     return -1;
                 }