diff --git a/AsyncDisplayKit/ASCollectionView.h b/AsyncDisplayKit/ASCollectionView.h
index ea812839..ca86cf3a 100644
--- a/AsyncDisplayKit/ASCollectionView.h
+++ b/AsyncDisplayKit/ASCollectionView.h
@@ -301,8 +301,13 @@ NS_ASSUME_NONNULL_BEGIN
  * @param cellNode a cellNode part of the collection view
  *
  * @return an indexPath for this cellNode
+ *
+ * @discussion This method will return @c nil for a node that is still being
+ *   displayed in the collection view, if the data source has deleted the item.
+ *   That is, the node is visible but it no longer corresponds
+ *   to any item in the data source and will be removed soon.
  */
-- (NSIndexPath *)indexPathForNode:(ASCellNode *)cellNode;
+- (nullable NSIndexPath *)indexPathForNode:(ASCellNode *)cellNode;
 
 /**
  * Similar to -visibleCells.
diff --git a/AsyncDisplayKit/ASTableView.h b/AsyncDisplayKit/ASTableView.h
index 74f99e85..f9f41fb5 100644
--- a/AsyncDisplayKit/ASTableView.h
+++ b/AsyncDisplayKit/ASTableView.h
@@ -278,7 +278,7 @@ NS_ASSUME_NONNULL_BEGIN
  *
  * @return a node for display at this indexpath.
  */
-- (ASCellNode *)nodeForRowAtIndexPath:(NSIndexPath *)indexPath;
+- (nullable ASCellNode *)nodeForRowAtIndexPath:(NSIndexPath *)indexPath;
 
 /**
  * Similar to -indexPathForCell:.
@@ -286,6 +286,11 @@ NS_ASSUME_NONNULL_BEGIN
  * @param cellNode a cellNode part of the table view
  *
  * @return an indexPath for this cellNode
+ *
+ * @discussion This method will return @c nil for a node that is still being
+ *   displayed in the table view, if the data source has deleted the row.
+ *   That is, the node is visible but it no longer corresponds
+ *   to any item in the data source and will be removed soon.
  */
 - (nullable NSIndexPath *)indexPathForNode:(ASCellNode *)cellNode;