[7.1.x] fix comparison of dataclasses with InitVar

testing/example_scripts/dataclasses/test_compare_initvar.py

@@ -0,0 +1,12 @@
+from dataclasses import dataclass
+from dataclasses import InitVar
+
+
+@dataclass
+class Foo:
+    init_only: InitVar[int]
+    real_attr: int
+
+
+def test_demonstrate():
+    assert Foo(1, 2) == Foo(1, 3)