Document vars behavior when __dict__ is missing (#21466)

diff --git a/Doc/library/functions.rst b/Doc/library/functions.rst
index 43c47c1da9434c3af1b7347de690ca72e6f186dc..d381d43d8e99c35a8637be4a88340171a4470de8 100644 (file)
--- a/Doc/library/functions.rst
+++ b/Doc/library/functions.rst
@@ -1734,6 +1734,9 @@ are always available.  They are listed here in alphabetical order.
    locals dictionary is only useful for reads since updates to the locals
    dictionary are ignored.
 
+   A :exc:`TypeError` exception is raised if an object is specified but
+   it doesn't have a :attr:`~object.__dict__` attribute (for example, if
+   its class defines the :attr:`~object.__slots__` attribute).
 
 .. function:: zip(*iterables, strict=False)