(Merge 3.3) Parser/asdl_c.py: use Py_CLEAR()

diff --cc Parser/asdl_c.py
Simple merge

diff --cc Python/Python-ast.c
index 776055fa3442c64b58903071400ee752f3bc8783,d78657ce0755b2f89fd37565e3906e6371c50bb9..49d19dacd6ec542c9d348a943c4baccaf8734ac9
--- 1/Python/Python-ast.c
--- 2/Python/Python-ast.c
+++ b/Python/Python-ast.c
@@@ -5738,29 -5584,6 +5647,28 @@@ obj2ast_expr(PyObject* obj, expr_ty* ou
          if (*out == NULL) goto failed;
          return 0;
      }
-             Py_XDECREF(tmp);
-             tmp = NULL;
 +    isinstance = PyObject_IsInstance(obj, (PyObject*)NameConstant_type);
 +    if (isinstance == -1) {
 +        return 1;
 +    }
 +    if (isinstance) {
 +        singleton value;
 +
 +        if (_PyObject_HasAttrId(obj, &PyId_value)) {
 +            int res;
 +            tmp = _PyObject_GetAttrId(obj, &PyId_value);
 +            if (tmp == NULL) goto failed;
 +            res = obj2ast_singleton(tmp, &value, arena);
 +            if (res != 0) goto failed;
++            Py_CLEAR(tmp);
 +        } else {
 +            PyErr_SetString(PyExc_TypeError, "required field \"value\" missing from NameConstant");
 +            return 1;
 +        }
 +        *out = NameConstant(value, lineno, col_offset, arena);
 +        if (*out == NULL) goto failed;
 +        return 0;
 +    }
      isinstance = PyObject_IsInstance(obj, (PyObject*)Ellipsis_type);
      if (isinstance == -1) {
          return 1;
@@@ -6699,10 -6496,9 +6579,9 @@@ obj2ast_arguments(PyObject* obj, argume
          int res;
          tmp = _PyObject_GetAttrId(obj, &PyId_vararg);
          if (tmp == NULL) goto failed;
 -        res = obj2ast_identifier(tmp, &vararg, arena);
 +        res = obj2ast_arg(tmp, &vararg, arena);
          if (res != 0) goto failed;
-         Py_XDECREF(tmp);
-         tmp = NULL;
+         Py_CLEAR(tmp);
      } else {
          vararg = NULL;
      }
@@@ -6731,41 -6536,25 +6609,39 @@@
          PyErr_SetString(PyExc_TypeError, "required field \"kwonlyargs\" missing from arguments");
          return 1;
      }
 -    if (_PyObject_HasAttrId(obj, &PyId_kwarg)) {
 +    if (_PyObject_HasAttrId(obj, &PyId_kw_defaults)) {
          int res;
 -        tmp = _PyObject_GetAttrId(obj, &PyId_kwarg);
 +        Py_ssize_t len;
 +        Py_ssize_t i;
 +        tmp = _PyObject_GetAttrId(obj, &PyId_kw_defaults);
          if (tmp == NULL) goto failed;
 -        res = obj2ast_identifier(tmp, &kwarg, arena);
 -        if (res != 0) goto failed;
 +        if (!PyList_Check(tmp)) {
 +            PyErr_Format(PyExc_TypeError, "arguments field \"kw_defaults\" must be a list, not a %.200s", tmp->ob_type->tp_name);
 +            goto failed;
 +        }
 +        len = PyList_GET_SIZE(tmp);
 +        kw_defaults = asdl_seq_new(len, arena);
 +        if (kw_defaults == NULL) goto failed;
 +        for (i = 0; i < len; i++) {
 +            expr_ty value;
 +            res = obj2ast_expr(PyList_GET_ITEM(tmp, i), &value, arena);
 +            if (res != 0) goto failed;
 +            asdl_seq_SET(kw_defaults, i, value);
 +        }
-         Py_XDECREF(tmp);
-         tmp = NULL;
+         Py_CLEAR(tmp);
      } else {
 -        kwarg = NULL;
 +        PyErr_SetString(PyExc_TypeError, "required field \"kw_defaults\" missing from arguments");
 +        return 1;
      }
 -    if (_PyObject_HasAttrId(obj, &PyId_kwargannotation)) {
 +    if (exists_not_none(obj, &PyId_kwarg)) {
          int res;
 -        tmp = _PyObject_GetAttrId(obj, &PyId_kwargannotation);
 +        tmp = _PyObject_GetAttrId(obj, &PyId_kwarg);
          if (tmp == NULL) goto failed;
 -        res = obj2ast_expr(tmp, &kwargannotation, arena);
 +        res = obj2ast_arg(tmp, &kwarg, arena);
          if (res != 0) goto failed;
-         Py_XDECREF(tmp);
-         tmp = NULL;
+         Py_CLEAR(tmp);
      } else {
 -        kwargannotation = NULL;
 +        kwarg = NULL;
      }
      if (_PyObject_HasAttrId(obj, &PyId_defaults)) {
          int res;