cpython-tracerefs % ../../cpython/configure -C --with-trace-refs --with-pydebug
[...]
cpython-tracerefs % make
[...]
cpython-tracerefs % ./python -m test test_int
0:00:00 load avg: 2.79 Run tests sequentially
0:00:00 load avg: 2.79 [1/1] test_int

== Tests result: SUCCESS ==

1 test OK.

Total duration: 477 ms
Tests result: SUCCESS
../../cpython/Objects/object.c:2234: _Py_ForgetReference: Assertion failed: invalid object chain
Enable tracemalloc to get the memory block allocation traceback

object address  : 0x7ff86d998050
object refcount : 0
object type     : 0x55fbc49aba60
object type name: dict
object repr     : <refcnt 0 at 0x7ff86d998050>

Fatal Python error: _PyObject_AssertFailed: _PyObject_AssertFailed
Python runtime state: finalizing (tstate=0x000055fbc4b27e88)

Current thread 0x00007ff86daec740 (most recent call first):
  <no Python frame>
Aborted