Issue #477863: Print a warning at shutdown if gc.garbage is not empty.
diff --git a/Doc/library/gc.rst b/Doc/library/gc.rst
index a5c9e7b..29afc96 100644
--- a/Doc/library/gc.rst
+++ b/Doc/library/gc.rst
@@ -177,6 +177,15 @@
    If :const:`DEBUG_SAVEALL` is set, then all unreachable objects will be added to
    this list rather than freed.
 
+   .. versionchanged:: 3.2
+      If this list is non-empty at interpreter shutdown, a warning message
+      gets printed:
+
+   ::
+
+      gc: 2 uncollectable objects at shutdown:
+          Use gc.set_debug(gc.DEBUG_UNCOLLECTABLE) to list them.
+
 The following constants are provided for use with :func:`set_debug`:
 
 
@@ -197,6 +206,9 @@
    reachable but cannot be freed by the collector).  These objects will be added to
    the ``garbage`` list.
 
+   .. versionchanged:: 3.2
+      Also print the contents of the :data:`garbage` list at interpreter
+      shutdown (rather than just its length), if it isn't empty.
 
 .. data:: DEBUG_SAVEALL