1 files changed, 7 insertions, 3 deletions
diff --git a/sphinx/pycode/nodes.py b/sphinx/pycode/nodes.py
index e3a1bc9f6..b4b681d78 100644
--- a/sphinx/pycode/nodes.py
+++ b/sphinx/pycode/nodes.py
@@ -9,12 +9,16 @@
     :license: BSD, see LICENSE for details.
 """
 
+if False:
+    # For type annotation
+    from typing import Callable  # NOQA
+
 
 class BaseNode(object):
     """
     Node superclass for both terminal and nonterminal nodes.
     """
-    parent = None
+    parent = None  # type: BaseNode
 
     def _eq(self, other):
         raise NotImplementedError
@@ -29,7 +33,7 @@ class BaseNode(object):
             return NotImplemented
         return not self._eq(other)
 
-    __hash__ = None
+    __hash__ = None  # type: Callable[[object], int]
 
     def get_prev_sibling(self):
         """Return previous child in parent's children, or None."""
@@ -204,5 +208,5 @@ class NodeVisitor(object):
     def generic_visit(self, node):
         """Called if no explicit visitor function exists for a node."""
         if isinstance(node, Node):
-            for child in node:
+            for child in node:  # type: ignore
                 self.visit(child)