Merge 3.5 (Issue #19235)

Modules/_pickle.c

@@ -3622,7 +3622,7 @@ save_reduce(PicklerObject *self, PyObject *args, PyObject *obj)
              >>> pickle.dumps(1+2j)
              Traceback (most recent call last):
                ...
-             RuntimeError: maximum recursion depth exceeded
+             RecursionError: maximum recursion depth exceeded
 
            Removing the complex class from copyreg.dispatch_table made the
            __reduce_ex__() method emit another complex object:

Modules/_sre.c

@@ -497,8 +497,9 @@ pattern_error(Py_ssize_t status)
 {
     switch (status) {
     case SRE_ERROR_RECURSION_LIMIT:
+        /* This error code seems to be unused. */
         PyErr_SetString(
-            PyExc_RuntimeError,
+            PyExc_RecursionError,
             "maximum recursion limit exceeded"
             );
         break;