diff --git a/Modules/_io/_iomodule.c b/Modules/_io/_iomodule.c
index 99b8a8e09ecf0a..ce9fcca971f99d 100644
--- a/Modules/_io/_iomodule.c
+++ b/Modules/_io/_iomodule.c
@@ -660,7 +660,6 @@ struct PyModuleDef _PyIO_Module = {
 static PyTypeObject* static_types[] = {
     // Base classes
     &PyIOBase_Type,
-    &PyIncrementalNewlineDecoder_Type,
 
     // PyIOBase_Type subclasses
     &PyBufferedIOBase_Type,
@@ -757,7 +756,7 @@ PyInit__io(void)
     }
 
     // Base classes
-    state->PyIncrementalNewlineDecoder_Type = (PyTypeObject *)Py_NewRef(&PyIncrementalNewlineDecoder_Type);
+    ADD_TYPE(m, state->PyIncrementalNewlineDecoder_Type, &nldecoder_spec, NULL);
 
     // PyIOBase_Type subclasses
     state->PyRawIOBase_Type = (PyTypeObject *)Py_NewRef(&PyRawIOBase_Type);
diff --git a/Modules/_io/_iomodule.h b/Modules/_io/_iomodule.h
index c971c987cf5fee..f191cea7fcc47b 100644
--- a/Modules/_io/_iomodule.h
+++ b/Modules/_io/_iomodule.h
@@ -14,9 +14,6 @@ extern PyTypeObject PyRawIOBase_Type;
 extern PyTypeObject PyBufferedIOBase_Type;
 extern PyTypeObject PyTextIOBase_Type;
 
-/* Concrete classes */
-extern PyTypeObject PyIncrementalNewlineDecoder_Type;
-
 /* Type specs */
 extern PyType_Spec bufferedrandom_spec;
 extern PyType_Spec bufferedreader_spec;
@@ -24,6 +21,7 @@ extern PyType_Spec bufferedrwpair_spec;
 extern PyType_Spec bufferedwriter_spec;
 extern PyType_Spec bytesio_spec;
 extern PyType_Spec fileio_spec;
+extern PyType_Spec nldecoder_spec;
 extern PyType_Spec stringio_spec;
 extern PyType_Spec textiowrapper_spec;
 
diff --git a/Modules/_io/textio.c b/Modules/_io/textio.c
index 2dba382f4f8fb0..070687a83d1bc2 100644
--- a/Modules/_io/textio.c
+++ b/Modules/_io/textio.c
@@ -248,12 +248,32 @@ _io_IncrementalNewlineDecoder___init___impl(nldecoder_object *self,
     return 0;
 }
 
-static void
-incrementalnewlinedecoder_dealloc(nldecoder_object *self)
+static int
+incrementalnewlinedecoder_traverse(nldecoder_object *self, visitproc visit,
+                                   void *arg)
+{
+    Py_VISIT(Py_TYPE(self));
+    Py_VISIT(self->decoder);
+    Py_VISIT(self->errors);
+    return 0;
+}
+
+static int
+incrementalnewlinedecoder_clear(nldecoder_object *self)
 {
     Py_CLEAR(self->decoder);
     Py_CLEAR(self->errors);
-    Py_TYPE(self)->tp_free((PyObject *)self);
+    return 0;
+}
+
+static void
+incrementalnewlinedecoder_dealloc(nldecoder_object *self)
+{
+    PyTypeObject *tp = Py_TYPE(self);
+    _PyObject_GC_UNTRACK(self);
+    (void)incrementalnewlinedecoder_clear(self);
+    tp->tp_free((PyObject *)self);
+    Py_DECREF(tp);
 }
 
 static int
@@ -3176,45 +3196,23 @@ static PyGetSetDef incrementalnewlinedecoder_getset[] = {
     {NULL}
 };
 
-PyTypeObject PyIncrementalNewlineDecoder_Type = {
-    PyVarObject_HEAD_INIT(NULL, 0)
-    "_io.IncrementalNewlineDecoder", /*tp_name*/
-    sizeof(nldecoder_object), /*tp_basicsize*/
-    0,                          /*tp_itemsize*/
-    (destructor)incrementalnewlinedecoder_dealloc, /*tp_dealloc*/
-    0,                          /*tp_vectorcall_offset*/
-    0,                          /*tp_getattr*/
-    0,                          /*tp_setattr*/
-    0,                          /*tp_as_async*/
-    0,                          /*tp_repr*/
-    0,                          /*tp_as_number*/
-    0,                          /*tp_as_sequence*/
-    0,                          /*tp_as_mapping*/
-    0,                          /*tp_hash */
-    0,                          /*tp_call*/
-    0,                          /*tp_str*/
-    0,                          /*tp_getattro*/
-    0,                          /*tp_setattro*/
-    0,                          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE,  /*tp_flags*/
-    _io_IncrementalNewlineDecoder___init____doc__, /* tp_doc */
-    0,                          /* tp_traverse */
-    0,                          /* tp_clear */
-    0,                          /* tp_richcompare */
-    0,                          /*tp_weaklistoffset*/
-    0,                          /* tp_iter */
-    0,                          /* tp_iternext */
-    incrementalnewlinedecoder_methods, /* tp_methods */
-    0,                          /* tp_members */
-    incrementalnewlinedecoder_getset, /* tp_getset */
-    0,                          /* tp_base */
-    0,                          /* tp_dict */
-    0,                          /* tp_descr_get */
-    0,                          /* tp_descr_set */
-    0,                          /* tp_dictoffset */
-    _io_IncrementalNewlineDecoder___init__, /* tp_init */
-    0,                          /* tp_alloc */
-    PyType_GenericNew,          /* tp_new */
+static PyType_Slot nldecoder_slots[] = {
+    {Py_tp_dealloc, incrementalnewlinedecoder_dealloc},
+    {Py_tp_doc, (void *)_io_IncrementalNewlineDecoder___init____doc__},
+    {Py_tp_methods, incrementalnewlinedecoder_methods},
+    {Py_tp_getset, incrementalnewlinedecoder_getset},
+    {Py_tp_traverse, incrementalnewlinedecoder_traverse},
+    {Py_tp_clear, incrementalnewlinedecoder_clear},
+    {Py_tp_init, _io_IncrementalNewlineDecoder___init__},
+    {0, NULL},
+};
+
+PyType_Spec nldecoder_spec = {
+    .name = "_io.IncrementalNewlineDecoder",
+    .basicsize = sizeof(nldecoder_object),
+    .flags = (Py_TPFLAGS_DEFAULT | Py_TPFLAGS_BASETYPE | Py_TPFLAGS_HAVE_GC |
+              Py_TPFLAGS_IMMUTABLETYPE),
+    .slots = nldecoder_slots,
 };
 
 
diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 165bd74587d7c7..b195dab9ccc83c 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -321,7 +321,6 @@ Modules/_io/bufferedio.c	-	PyBufferedIOBase_Type	-
 Modules/_io/bytesio.c	-	_PyBytesIOBuffer_Type	-
 Modules/_io/iobase.c	-	PyIOBase_Type	-
 Modules/_io/iobase.c	-	PyRawIOBase_Type	-
-Modules/_io/textio.c	-	PyIncrementalNewlineDecoder_Type	-
 Modules/_io/textio.c	-	PyTextIOBase_Type	-
 Modules/_io/winconsoleio.c	-	PyWindowsConsoleIO_Type	-
 Modules/_testcapi/vectorcall.c	-	MethodDescriptorBase_Type	-