Fix named tuples to work with vars().

Doc/library/collections.rst

@@ -622,6 +622,8 @@ they add the ability to access fields by name instead of position index.
            def _asdict(self):
                'Return a new OrderedDict which maps field names to their values'
                return OrderedDict(zip(self._fields, self))
+   <BLANKLINE>
+           __dict__ = property(_asdict)
    <BLANKLINE>
            def _replace(_self, **kwds):
                'Return a new Point object replacing specified fields with new values'

Lib/collections.py

@@ -268,6 +268,8 @@ class {typename}(tuple):
         'Return a new OrderedDict which maps field names to their values'
         return OrderedDict(zip(self._fields, self))
 
+    __dict__ = property(_asdict)
+
     def _replace(_self, **kwds):
         'Return a new {typename} object replacing specified fields with new values'
         result = _self._make(map(kwds.pop, {field_names!r}, _self))

Lib/test/test_collections.py

@@ -180,12 +180,12 @@ class TestNamedTuple(unittest.TestCase):
         self.assertRaises(TypeError, eval, 'Point(XXX=1, y=2)', locals())   # wrong keyword argument
         self.assertRaises(TypeError, eval, 'Point(x=1)', locals())          # missing keyword argument
         self.assertEqual(repr(p), 'Point(x=11, y=22)')
-        self.assertNotIn('__dict__', dir(p))                              # verify instance has no dict
         self.assertNotIn('__weakref__', dir(p))
         self.assertEqual(p, Point._make([11, 22]))                          # test _make classmethod
         self.assertEqual(p._fields, ('x', 'y'))                             # test _fields attribute
         self.assertEqual(p._replace(x=1), (1, 22))                          # test _replace method
         self.assertEqual(p._asdict(), dict(x=11, y=22))                     # test _asdict method
+        self.assertEqual(vars(p), p._asdict())                              # verify that vars() works
 
         try:
             p._replace(x=1, error=2)

Misc/NEWS

@@ -22,6 +22,8 @@ Core and Builtins
 Library
 -------
 
+- Named tuples now work correctly with vars().
+
 - Issue #12085: Fix an attribute error in subprocess.Popen destructor if the
   constructor has failed, e.g. because of an undeclared keyword argument. Patch
   written by Oleg Oshmyan.