clarified whatsnew

jschendel · jschendel · commit 0852ecbbc5bf · 2017-11-23T16:53:34.000-07:00
diff --git a/doc/source/whatsnew/v0.22.0.txt b/doc/source/whatsnew/v0.22.0.txt
@@ -52,7 +52,7 @@ Backwards incompatible API changes
 
 - :func:`Series.fillna` now raises a ``TypeError`` instead of a ``ValueError`` when passed a list, tuple or DataFrame as a ``value`` (:issue:`18293`)
 - :func:`pandas.DataFrame.merge` no longer casts a ``float`` column to ``object`` when merging on ``int`` and ``float`` columns (:issue:`16572`)
-- The default NA value for :class:`UInt64Index` has changed from 0 to ``NaN`` (:issue:`18398`)
+- The default NA value for :class:`UInt64Index` has changed from 0 to ``NaN``, which impacts methods that mask with NA, such as ``UInt64Index.where()`` (:issue:`18398`)
 -
 
 

Original file line number	Diff line number	Diff line change
`@@ -52,7 +52,7 @@ Backwards incompatible API changes`
`52`	`52`
`53`	`53`	- :func:`Series.fillna` now raises a ``TypeError`` instead of a ``ValueError`` when passed a list, tuple or DataFrame as a ``value`` (:issue:`18293`)
`54`	`54`	- :func:`pandas.DataFrame.merge` no longer casts a ``float`` column to ``object`` when merging on ``int`` and ``float`` columns (:issue:`16572`)
`55`		-- The default NA value for :class:`UInt64Index` has changed from 0 to ``NaN`` (:issue:`18398`)
	`55`	+- The default NA value for :class:`UInt64Index` has changed from 0 to ``NaN``, which impacts methods that mask with NA, such as ``UInt64Index.where()`` (:issue:`18398`)
`56`	`56`	`-`
`57`	`57`
`58`	`58`