Issue #9930: Remove an unnecessary type check in wrap_binaryfunc_r;
this was causing reversed method calls like float.__radd__(3.0, 1) to
return NotImplemented instead of the expected numeric value.
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
index 0979880..47fecfe 100644
--- a/Lib/test/test_descr.py
+++ b/Lib/test/test_descr.py
@@ -285,6 +285,11 @@
         self.assertEqual(repr(a), "234.5")
         self.assertEqual(a.prec, 12)
 
+    def test_explicit_reverse_methods(self):
+        # see issue 9930
+        self.assertEqual(complex.__radd__(3j, 4.0), complex(4.0, 3.0))
+        self.assertEqual(float.__rsub__(3.0, 1), -2.0)
+
     @support.impl_detail("the module 'xxsubtype' is internal")
     def test_spam_lists(self):
         # Testing spamlist operations...
diff --git a/Misc/NEWS b/Misc/NEWS
index 9480cf4..c353810 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -10,6 +10,10 @@
 Core and Builtins
 -----------------
 
+- Issue #9930: Remove bogus subtype check that was causing (e.g.)
+  float.__rdiv__(2.0, 3) to return NotImplemented instead of the
+  expected 1.5.
+
 - Issue #9808: Implement os.getlogin for Windows. Patch by Jon Anglin.
 
 - Issue #9901: Destroying the GIL in Py_Finalize() can fail if some other
diff --git a/Objects/typeobject.c b/Objects/typeobject.c
index 897374d..7bdcb12 100644
--- a/Objects/typeobject.c
+++ b/Objects/typeobject.c
@@ -4063,10 +4063,6 @@
     if (!check_num_args(args, 1))
         return NULL;
     other = PyTuple_GET_ITEM(args, 0);
-    if (!PyType_IsSubtype(Py_TYPE(other), Py_TYPE(self))) {
-        Py_INCREF(Py_NotImplemented);
-        return Py_NotImplemented;
-    }
     return (*func)(other, self);
 }