diff --git a/Modules/_collectionsmodule.c b/Modules/_collectionsmodule.c
index 64f8fa9ab4041fb..f62972ac8e4901f 100644
--- a/Modules/_collectionsmodule.c
+++ b/Modules/_collectionsmodule.c
@@ -674,8 +674,18 @@ deque___copy___impl(dequeobject *deque)
     return deque_copy_impl(deque);
 }
 
+/*[clinic input]
+@critical_section
+_collections.deque.__add__ as deque_concat
+
+    deque: dequeobject
+    other: object
+    /
+[clinic start generated code]*/
+
 static PyObject *
-deque_concat_lock_held(dequeobject *deque, PyObject *other)
+deque_concat_impl(dequeobject *deque, PyObject *other)
+/*[clinic end generated code: output=fa6c28f7752f0b28 input=1816c51a4c6c4f05]*/
 {
     PyObject *new_deque, *result;
     int rv;
@@ -706,17 +716,6 @@ deque_concat_lock_held(dequeobject *deque, PyObject *other)
     return new_deque;
 }
 
-static PyObject *
-deque_concat(PyObject *self, PyObject *other)
-{
-    dequeobject *deque = dequeobject_CAST(self);
-    PyObject *result;
-    Py_BEGIN_CRITICAL_SECTION(deque);
-    result = deque_concat_lock_held(deque, other);
-    Py_END_CRITICAL_SECTION();
-    return result;
-}
-
 static int
 deque_clear(PyObject *self)
 {
diff --git a/Modules/clinic/_collectionsmodule.c.h b/Modules/clinic/_collectionsmodule.c.h
index cef17347078fe4e..7545d22b21e655c 100644
--- a/Modules/clinic/_collectionsmodule.c.h
+++ b/Modules/clinic/_collectionsmodule.c.h
@@ -202,6 +202,21 @@ deque___copy__(PyObject *deque, PyObject *Py_UNUSED(ignored))
     return return_value;
 }
 
+static PyObject *
+deque_concat_impl(dequeobject *deque, PyObject *other);
+
+static PyObject *
+deque_concat(PyObject *deque, PyObject *other)
+{
+    PyObject *return_value = NULL;
+
+    Py_BEGIN_CRITICAL_SECTION(deque);
+    return_value = deque_concat_impl((dequeobject *)deque, other);
+    Py_END_CRITICAL_SECTION();
+
+    return return_value;
+}
+
 PyDoc_STRVAR(deque_clearmethod__doc__,
 "clear($self, /)\n"
 "--\n"
@@ -662,4 +677,4 @@ tuplegetter_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 exit:
     return return_value;
 }
-/*[clinic end generated code: output=fe575846d0131efd input=a9049054013a1b77]*/
+/*[clinic end generated code: output=761d85edf8291792 input=a9049054013a1b77]*/
diff --git a/Objects/bytearrayobject.c b/Objects/bytearrayobject.c
index 5abd0fd235f030e..9c0127ee4751b60 100644
--- a/Objects/bytearrayobject.c
+++ b/Objects/bytearrayobject.c
@@ -403,11 +403,19 @@ bytearray_length(PyObject *op)
     return PyByteArray_GET_SIZE(op);
 }
 
+/*[clinic input]
+@critical_section
+bytearray.__iadd__ as bytearray_iconcat
+
+    other: object
+    /
+[clinic start generated code]*/
+
 static PyObject *
-bytearray_iconcat_lock_held(PyObject *op, PyObject *other)
+bytearray_iconcat_impl(PyByteArrayObject *self, PyObject *other)
+/*[clinic end generated code: output=ba172f2db8f7a8dd input=5b6fb07ab387084d]*/
 {
-    _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(op);
-    PyByteArrayObject *self = _PyByteArray_CAST(op);
+    _Py_CRITICAL_SECTION_ASSERT_OBJECT_LOCKED(self);
 
     Py_buffer vo;
     if (PyObject_GetBuffer(other, &vo, PyBUF_SIMPLE) != 0) {
@@ -432,16 +440,6 @@ bytearray_iconcat_lock_held(PyObject *op, PyObject *other)
     return Py_NewRef(self);
 }
 
-static PyObject *
-bytearray_iconcat(PyObject *op, PyObject *other)
-{
-    PyObject *ret;
-    Py_BEGIN_CRITICAL_SECTION(op);
-    ret = bytearray_iconcat_lock_held(op, other);
-    Py_END_CRITICAL_SECTION();
-    return ret;
-}
-
 /*[clinic input]
 @critical_section
 bytearray.__mul__ as bytearray_repeat
diff --git a/Objects/clinic/bytearrayobject.c.h b/Objects/clinic/bytearrayobject.c.h
index a41866b40f80555..e130ced76a93fe6 100644
--- a/Objects/clinic/bytearrayobject.c.h
+++ b/Objects/clinic/bytearrayobject.c.h
@@ -11,6 +11,21 @@ preserve
 #include "pycore_runtime.h"       // _Py_SINGLETON()
 #include "pycore_unicodeobject.h" // _PyUnicode_AsUTF8NoNUL()
 
+static PyObject *
+bytearray_iconcat_impl(PyByteArrayObject *self, PyObject *other);
+
+static PyObject *
+bytearray_iconcat(PyObject *self, PyObject *other)
+{
+    PyObject *return_value = NULL;
+
+    Py_BEGIN_CRITICAL_SECTION(self);
+    return_value = bytearray_iconcat_impl((PyByteArrayObject *)self, other);
+    Py_END_CRITICAL_SECTION();
+
+    return return_value;
+}
+
 static PyObject *
 bytearray_repeat_impl(PyByteArrayObject *self, Py_ssize_t count);
 
@@ -2007,4 +2022,4 @@ bytearray_sizeof(PyObject *self, PyObject *Py_UNUSED(ignored))
 {
     return bytearray_sizeof_impl((PyByteArrayObject *)self);
 }
-/*[clinic end generated code: output=a1a91ef777ab985f input=a9049054013a1b77]*/
+/*[clinic end generated code: output=f57debf4b0a990ca input=a9049054013a1b77]*/
diff --git a/Tools/clinic/libclinic/dsl_parser.py b/Tools/clinic/libclinic/dsl_parser.py
index f40b17408ba1eb1..a3512b9522322ab 100644
--- a/Tools/clinic/libclinic/dsl_parser.py
+++ b/Tools/clinic/libclinic/dsl_parser.py
@@ -40,7 +40,6 @@
 unsupported_special_methods: set[str] = set("""
 
 __abs__
-__add__
 __and__
 __call__
 __delitem__
@@ -54,7 +53,6 @@
 __getitem__
 __gt__
 __hash__
-__iadd__
 __iand__
 __ifloordiv__
 __ilshift__
diff --git a/Tools/clinic/libclinic/slots.py b/Tools/clinic/libclinic/slots.py
index 4c14959d3598f0e..c5158cc57fc9407 100644
--- a/Tools/clinic/libclinic/slots.py
+++ b/Tools/clinic/libclinic/slots.py
@@ -40,6 +40,8 @@ def make_return_converter(self) -> CReturnConverter:
 SLOTS: Final[dict[str, SlotSpec]] = {
     '__next__': SlotSpec(return_converter='object'),
     '__len__': SlotSpec(return_converter='Py_ssize_t'),
+    '__add__': SlotSpec(return_converter='object'),
+    '__iadd__': SlotSpec(return_converter='object'),
     '__mul__': SlotSpec(return_converter='object'),
     '__imul__': SlotSpec(return_converter='object'),
     '__repr__': SlotSpec(return_converter='object'),