diff --git a/Python/ast.c b/Python/ast.c
index 1cf100e..df94850 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1321,13 +1321,14 @@
             if (PyErr_ExceptionMatches(PyExc_UnicodeError)) {
                 PyObject *type, *value, *tback, *errstr;
                 PyErr_Fetch(&type, &value, &tback);
-                errstr = ((PyUnicodeErrorObject *)value)->reason;
+                errstr = PyObject_Str(value);
                 if (errstr) {
                     char *s = "";
                     char buf[128];
                     s = _PyUnicode_AsString(errstr);
                     PyOS_snprintf(buf, sizeof(buf), "(unicode error) %s", s);
                     ast_error(n, buf);
+                    Py_DECREF(errstr);
                 } else {
                     ast_error(n, "(unicode error) unknown error");
                 }