diff --git a/pyo3-derive-backend/src/defs.rs b/pyo3-derive-backend/src/defs.rs
index 43b4f06f..02a5ca74 100644
--- a/pyo3-derive-backend/src/defs.rs
+++ b/pyo3-derive-backend/src/defs.rs
@@ -602,10 +602,9 @@ pub const NUM: Proto = Proto {
             pyres: false,
             proto: "pyo3::class::number::PyNumberIModProtocol",
         },
-        MethodProto::Ternary {
+        MethodProto::Binary {
             name: "__ipow__",
-            arg1: "Other",
-            arg2: "Modulo",
+            arg: "Other",
             pyres: false,
             proto: "pyo3::class::number::PyNumberIPowProtocol",
         },
diff --git a/src/class/macros.rs b/src/class/macros.rs
index e2735939..a7de4c9b 100644
--- a/src/class/macros.rs
+++ b/src/class/macros.rs
@@ -302,14 +302,16 @@ macro_rules! py_ternary_reverse_num_func {
     }};
 }
 
+// NOTE(kngwyu): Somehow __ipow__ causes SIGSEGV in Python < 3.8 when we extract arg2,
+// so we ignore it. It's the same as what CPython does.
 #[macro_export]
 #[doc(hidden)]
-macro_rules! py_ternary_self_func {
+macro_rules! py_dummy_ternary_self_func {
     ($trait:ident, $class:ident :: $f:ident) => {{
         unsafe extern "C" fn wrap<T>(
             slf: *mut $crate::ffi::PyObject,
             arg1: *mut $crate::ffi::PyObject,
-            arg2: *mut $crate::ffi::PyObject,
+            _arg2: *mut $crate::ffi::PyObject,
         ) -> *mut $crate::ffi::PyObject
         where
             T: for<'p> $trait<'p>,
@@ -318,20 +320,18 @@ macro_rules! py_ternary_self_func {
 
             let py = $crate::Python::assume_gil_acquired();
             let _pool = $crate::GILPool::new(py);
-            let slf_cell = py.from_borrowed_ptr::<$crate::PyCell<T>>(slf);
-            let arg1 = py.from_borrowed_ptr::<$crate::PyAny>(arg1);
-            let arg2 = py.from_borrowed_ptr::<$crate::PyAny>(arg2);
-            let result = call_mut!(slf_cell, $f, arg1, arg2);
+            let slf_ = py.from_borrowed_ptr::<$crate::PyCell<T>>(slf);
+            let arg = py.from_borrowed_ptr::<$crate::PyAny>(arg1);
+            let result = call_mut!(slf_, $f, arg);
             match result {
                 Ok(_) => {
-                    // Without this INCREF, SIGSEGV happens...
                     ffi::Py_INCREF(slf);
                     slf
                 }
                 Err(e) => e.restore_and_null(py),
             }
         }
-        Some(wrap::<T>)
+        Some(wrap::<$class>)
     }};
 }
 
diff --git a/src/class/number.rs b/src/class/number.rs
index 68079489..b845d2e0 100644
--- a/src/class/number.rs
+++ b/src/class/number.rs
@@ -224,7 +224,7 @@ pub trait PyNumberProtocol<'p>: PyClass {
     {
         unimplemented!()
     }
-    fn __ipow__(&'p mut self, other: Self::Other, modulo: Option<Self::Modulo>) -> Self::Result
+    fn __ipow__(&'p mut self, other: Self::Other) -> Self::Result
     where
         Self: PyNumberIPowProtocol<'p>,
     {
@@ -544,7 +544,6 @@ pub trait PyNumberIDivmodProtocol<'p>: PyNumberProtocol<'p> {
 
 pub trait PyNumberIPowProtocol<'p>: PyNumberProtocol<'p> {
     type Other: FromPyObject<'p>;
-    type Modulo: FromPyObject<'p>;
     type Result: Into<PyResult<()>>;
 }
 
@@ -1280,7 +1279,7 @@ where
     T: for<'p> PyNumberIPowProtocol<'p>,
 {
     fn nb_inplace_power() -> Option<ffi::ternaryfunc> {
-        py_ternary_self_func!(PyNumberIPowProtocol, T::__ipow__)
+        py_dummy_ternary_self_func!(PyNumberIPowProtocol, T::__ipow__)
     }
 }
 
diff --git a/tests/test_arithmetics.rs b/tests/test_arithmetics.rs
index c5de341e..2072ae04 100755
--- a/tests/test_arithmetics.rs
+++ b/tests/test_arithmetics.rs
@@ -121,7 +121,7 @@ impl PyNumberProtocol for InPlaceOperations {
         Ok(())
     }
 
-    fn __ipow__(&mut self, other: u32, _mod: Option<u32>) -> PyResult<()> {
+    fn __ipow__(&mut self, other: u32) -> PyResult<()> {
         self.value = self.value.pow(other);
         Ok(())
     }