@@ -1558,6 +1558,34 @@ class P(Protocol):
         with self.assertRaisesRegex(TypeError, "@runtime_checkable"):
             isinstance(1, P)
 
+    def test_protocol_init_method(self):  # see bpo-44806
+        class P(Protocol):
+            x: int
+
+        class D1(P):
+            pass
+
+        class D2(P):
+            def __init__(self, x):
+                self.x = x
+
+        class B:
+            def __init__(self, x):
+                self.x = x
+
+        class D3(P, B):
+            pass
+
+        with self.subTest(cls=D1):
+            with self.assertRaisesRegex(TypeError, r"D1\(\) takes no arguments"):
+                D1(x=1)
+
+        for cls in (D2, D3):
+            with self.subTest(cls=cls):
+                d = cls(x=1)
+
+                self.assertIsInstance(d, cls)
+                self.assertEqual(d.x, 1)
 
 class GenericTests(BaseTestCase):
 

@@ -1522,6 +1522,12 @@ def _proto_hook(other):
 
         # We have nothing more to do for non-protocols...
         if not cls._is_protocol:
+            if '__init__' not in cls.__dict__:
+                # bpo-44806: reset __init__ method to correct one
+                cls.__init__ = next(
+                    (b.__init__ for b in cls.__bases__ if b.__init__ is not _no_init),
+                    object.__init__,
+                )
             return
 
         # ... otherwise check consistency of bases, and prohibit instantiation.

diff --git a/Misc/NEWS.d/next/Library/2021-08-02-12-30-39.bpo-44806.q1ah2P.rst b/Misc/NEWS.d/next/Library/2021-08-02-12-30-39.bpo-44806.q1ah2P.rst
@@ -0,0 +1,3 @@
+Fix issue when ``typing.Protocol`` delivered class get ``__init__`` method
+that can accepts unlimited `*args` and `**kwargs`. Patch provided by Yurii
+Karabas.