gh-96151: Use a private name for passing builtins to dataclass. This now allows for a field named BUILTIN (gh-98143)

Lib/test/test_dataclasses.py

@@ -257,6 +257,14 @@ class TestCase(unittest.TestCase):
         c = C('foo')
         self.assertEqual(c.object, 'foo')
 
+    def test_field_named_BUILTINS_frozen(self):
+        # gh-96151
+        @dataclass(frozen=True)
+        class C:
+            BUILTINS: int
+        c = C(5)
+        self.assertEqual(c.BUILTINS, 5)
+
     def test_field_named_like_builtin(self):
         # Attribute names can shadow built-in names
         # since code generation is used.