diff --git a/Misc/NEWS b/Misc/NEWS
index 34bdb9d..d94d655 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -40,7 +40,9 @@
 - Issue #1631171: Re-implement the 'warnings' module in C (the original Python
   code has been kept as backup). This will allow for using the 'warning's
   machinery in such places as the parser where use of pure Python code is not
-  possible.
+  possible.  Both the ``showarning()`` and ``formatwarning()`` gain an
+  optional 'line' argument which is not called by default for
+  backwards-compatibility reasons.
 
 Library
 -------
diff --git a/Python/_warnings.c b/Python/_warnings.c
index 88afade..8f575ca 100644
--- a/Python/_warnings.c
+++ b/Python/_warnings.c
@@ -382,9 +382,6 @@
             
             res = PyObject_CallFunctionObjArgs(show_fxn, message, category,
                                                     filename, lineno_obj,
-                                                    Py_None,
-                                                    sourceline ?
-                                                        sourceline: Py_None,
                                                     NULL);
             Py_DECREF(show_fxn);
             Py_XDECREF(res);