Update test_dictcomps from CPython 3.10.5

Lib/test/test_dictcomps.py

@@ -79,7 +79,7 @@ class DictComprehensionTest(unittest.TestCase):
             compile("{x: y for y, x in ((1, 2), (3, 4))} = 5", "<test>",
                     "exec")
 
-        with self.assertRaisesRegex(SyntaxError, "cannot assign"):
+        with self.assertRaisesRegex(SyntaxError, "illegal expression"):
             compile("{x: y for y, x in ((1, 2), (3, 4))} += 5", "<test>",
                     "exec")
 
@@ -113,5 +113,22 @@ class DictComprehensionTest(unittest.TestCase):
         self.assertEqual(actual, expected)
         self.assertEqual(actual_calls, expected_calls)
 
+    def test_assignment_idiom_in_comprehensions(self):
+        expected = {1: 1, 2: 4, 3: 9, 4: 16}
+        actual = {j: j*j for i in range(4) for j in [i+1]}
+        self.assertEqual(actual, expected)
+        expected = {3: 2, 5: 6, 7: 12, 9: 20}
+        actual = {j+k: j*k for i in range(4) for j in [i+1] for k in [j+1]}
+        self.assertEqual(actual, expected)
+        expected = {3: 2, 5: 6, 7: 12, 9: 20}
+        actual = {j+k: j*k for i in range(4)  for j, k in [(i+1, i+2)]}
+        self.assertEqual(actual, expected)
+
+    def test_star_expression(self):
+        expected = {0: 0, 1: 1, 2: 4, 3: 9}
+        self.assertEqual({i: i*i for i in [*range(4)]}, expected)
+        self.assertEqual({i: i*i for i in (*range(4),)}, expected)
+
+
 if __name__ == "__main__":
     unittest.main()