diff --git a/psycopg/adapter_asis.c b/psycopg/adapter_asis.c
index 7f5d3850..a2a8f4dc 100644
--- a/psycopg/adapter_asis.c
+++ b/psycopg/adapter_asis.c
@@ -117,13 +117,6 @@ asis_setup(asisObject *self, PyObject *obj)
     return 0;
 }
 
-static int
-asis_traverse(asisObject *self, visitproc visit, void *arg)
-{
-    Py_VISIT(self->wrapped);
-    return 0;
-}
-
 static void
 asis_dealloc(PyObject* obj)
 {
@@ -187,9 +180,9 @@ PyTypeObject asisType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     asisType_doc, /*tp_doc*/
-    (traverseproc)asis_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_binary.c b/psycopg/adapter_binary.c
index 08f41b84..54f0f656 100644
--- a/psycopg/adapter_binary.c
+++ b/psycopg/adapter_binary.c
@@ -221,17 +221,6 @@ binary_setup(binaryObject *self, PyObject *str)
     return 0;
 }
 
-static int
-binary_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    binaryObject *self = (binaryObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    Py_VISIT(self->buffer);
-    Py_VISIT(self->conn);
-    return 0;
-}
-
 static void
 binary_dealloc(PyObject* obj)
 {
@@ -296,9 +285,9 @@ PyTypeObject binaryType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     binaryType_doc, /*tp_doc*/
-    binary_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_datetime.c b/psycopg/adapter_datetime.c
index 9713a5a5..67697fba 100644
--- a/psycopg/adapter_datetime.c
+++ b/psycopg/adapter_datetime.c
@@ -183,15 +183,6 @@ pydatetime_setup(pydatetimeObject *self, PyObject *obj, int type)
     return 0;
 }
 
-static int
-pydatetime_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    pydatetimeObject *self = (pydatetimeObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    return 0;
-}
-
 static void
 pydatetime_dealloc(PyObject* obj)
 {
@@ -254,9 +245,9 @@ PyTypeObject pydatetimeType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     pydatetimeType_doc, /*tp_doc*/
-    pydatetime_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_mxdatetime.c b/psycopg/adapter_mxdatetime.c
index 470f12fc..4696a9d0 100644
--- a/psycopg/adapter_mxdatetime.c
+++ b/psycopg/adapter_mxdatetime.c
@@ -172,15 +172,6 @@ mxdatetime_setup(mxdatetimeObject *self, PyObject *obj, int type)
     return 0;
 }
 
-static int
-mxdatetime_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    mxdatetimeObject *self = (mxdatetimeObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    return 0;
-}
-
 static void
 mxdatetime_dealloc(PyObject* obj)
 {
@@ -245,9 +236,9 @@ PyTypeObject mxdatetimeType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     mxdatetimeType_doc, /*tp_doc*/
-    mxdatetime_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_pboolean.c b/psycopg/adapter_pboolean.c
index 879e233d..f8cd9959 100644
--- a/psycopg/adapter_pboolean.c
+++ b/psycopg/adapter_pboolean.c
@@ -114,15 +114,6 @@ pboolean_setup(pbooleanObject *self, PyObject *obj)
     return 0;
 }
 
-static int
-pboolean_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    pbooleanObject *self = (pbooleanObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    return 0;
-}
-
 static void
 pboolean_dealloc(PyObject* obj)
 {
@@ -187,9 +178,9 @@ PyTypeObject pbooleanType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     pbooleanType_doc, /*tp_doc*/
-    pboolean_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_pdecimal.c b/psycopg/adapter_pdecimal.c
index 09748514..35721417 100644
--- a/psycopg/adapter_pdecimal.c
+++ b/psycopg/adapter_pdecimal.c
@@ -170,15 +170,6 @@ pdecimal_setup(pdecimalObject *self, PyObject *obj)
     return 0;
 }
 
-static int
-pdecimal_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    pdecimalObject *self = (pdecimalObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    return 0;
-}
-
 static void
 pdecimal_dealloc(PyObject* obj)
 {
@@ -243,9 +234,9 @@ PyTypeObject pdecimalType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     pdecimalType_doc, /*tp_doc*/
-    pdecimal_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_pfloat.c b/psycopg/adapter_pfloat.c
index abdc8a4c..7bb7a467 100644
--- a/psycopg/adapter_pfloat.c
+++ b/psycopg/adapter_pfloat.c
@@ -143,15 +143,6 @@ pfloat_setup(pfloatObject *self, PyObject *obj)
     return 0;
 }
 
-static int
-pfloat_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    pfloatObject *self = (pfloatObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    return 0;
-}
-
 static void
 pfloat_dealloc(PyObject* obj)
 {
@@ -216,9 +207,9 @@ PyTypeObject pfloatType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     pfloatType_doc, /*tp_doc*/
-    pfloat_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_pint.c b/psycopg/adapter_pint.c
index ece7a9ca..6465acec 100644
--- a/psycopg/adapter_pint.c
+++ b/psycopg/adapter_pint.c
@@ -129,15 +129,6 @@ pint_setup(pintObject *self, PyObject *obj)
     return 0;
 }
 
-static int
-pint_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    pintObject *self = (pintObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    return 0;
-}
-
 static void
 pint_dealloc(PyObject* obj)
 {
@@ -202,9 +193,9 @@ PyTypeObject pintType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     pintType_doc, /*tp_doc*/
-    pint_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/adapter_qstring.c b/psycopg/adapter_qstring.c
index 0d7fd6fe..6728017e 100644
--- a/psycopg/adapter_qstring.c
+++ b/psycopg/adapter_qstring.c
@@ -209,17 +209,6 @@ qstring_setup(qstringObject *self, PyObject *str)
     return 0;
 }
 
-static int
-qstring_traverse(PyObject *obj, visitproc visit, void *arg)
-{
-    qstringObject *self = (qstringObject *)obj;
-
-    Py_VISIT(self->wrapped);
-    Py_VISIT(self->buffer);
-    Py_VISIT(self->conn);
-    return 0;
-}
-
 static void
 qstring_dealloc(PyObject* obj)
 {
@@ -285,9 +274,9 @@ PyTypeObject qstringType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     qstringType_doc, /*tp_doc*/
-    qstring_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/
diff --git a/psycopg/diagnostics_type.c b/psycopg/diagnostics_type.c
index 77019bfb..c9f8a57a 100644
--- a/psycopg/diagnostics_type.c
+++ b/psycopg/diagnostics_type.c
@@ -133,13 +133,6 @@ diagnostics_init(diagnosticsObject *self, PyObject *args, PyObject *kwds)
     return 0;
 }
 
-static int
-diagnostics_traverse(diagnosticsObject *self, visitproc visit, void *arg)
-{
-    Py_VISIT(self->err);
-    return 0;
-}
-
 static void
 diagnostics_dealloc(diagnosticsObject* self)
 {
@@ -183,9 +176,9 @@ PyTypeObject diagnosticsType = {
     0,          /*tp_getattro*/
     0,          /*tp_setattro*/
     0,          /*tp_as_buffer*/
-    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE|Py_TPFLAGS_HAVE_GC, /*tp_flags*/
+    Py_TPFLAGS_DEFAULT|Py_TPFLAGS_BASETYPE, /*tp_flags*/
     diagnosticsType_doc, /*tp_doc*/
-    (traverseproc)diagnostics_traverse, /*tp_traverse*/
+    0,          /*tp_traverse*/
     0,          /*tp_clear*/
     0,          /*tp_richcompare*/
     0,          /*tp_weaklistoffset*/