gh-111874: Call __set_name__ on objects that define the method inside a typing.NamedTuple class dictionary as part of the creation of that class (#111876)

Co-authored-by: Jelle Zijlstra <jelle.zijlstra@gmail.com>

Lib/typing.py

@@ -2743,11 +2743,26 @@ class NamedTupleMeta(type):
             class_getitem = _generic_class_getitem
             nm_tpl.__class_getitem__ = classmethod(class_getitem)
         # update from user namespace without overriding special namedtuple attributes
-        for key in ns:
+        for key, val in ns.items():
             if key in _prohibited:
                 raise AttributeError("Cannot overwrite NamedTuple attribute " + key)
-            elif key not in _special and key not in nm_tpl._fields:
-                setattr(nm_tpl, key, ns[key])
+            elif key not in _special:
+                if key not in nm_tpl._fields:
+                    setattr(nm_tpl, key, val)
+                try:
+                    set_name = type(val).__set_name__
+                except AttributeError:
+                    pass
+                else:
+                    try:
+                        set_name(val, nm_tpl, key)
+                    except BaseException as e:
+                        e.add_note(
+                            f"Error calling __set_name__ on {type(val).__name__!r} "
+                            f"instance {key!r} in {typename!r}"
+                        )
+                        raise
+
         if Generic in bases:
             nm_tpl.__init_subclass__()
         return nm_tpl