3 files changed, 22 insertions, 2 deletions
diff --git a/Lib/test/libregrtest/refleak.py b/Lib/test/libregrtest/refleak.py
index 7da16cf..71a70af 100644
--- a/Lib/test/libregrtest/refleak.py
+++ b/Lib/test/libregrtest/refleak.py
@@ -201,8 +201,8 @@ def dash_R_cleanup(fs, ps, pic, zdc, abcs):
     # Clear caches
     clear_caches()
 
-    # Clear type cache at the end: previous function calls can modify types
-    sys._clear_type_cache()
+    # Clear other caches last (previous function calls can re-populate them):
+    sys._clear_internal_caches()
 
 
 def warm_caches():
diff --git a/Lib/test/test_capi/test_opt.py b/Lib/test/test_capi/test_opt.py
index 5c8c059..e6b1b55 100644
--- a/Lib/test/test_capi/test_opt.py
+++ b/Lib/test/test_capi/test_opt.py
@@ -1,5 +1,6 @@
 import contextlib
 import opcode
+import sys
 import textwrap
 import unittest
 
@@ -181,6 +182,21 @@ class TestExecutorInvalidation(unittest.TestCase):
         _testinternalcapi.invalidate_executors(f.__code__)
         self.assertFalse(exe.is_valid())
 
+    def test_sys__clear_internal_caches(self):
+        def f():
+            for _ in range(1000):
+                pass
+        opt = _testinternalcapi.get_uop_optimizer()
+        with temporary_optimizer(opt):
+            f()
+        exe = get_first_executor(f)
+        self.assertIsNotNone(exe)
+        self.assertTrue(exe.is_valid())
+        sys._clear_internal_caches()
+        self.assertFalse(exe.is_valid())
+        exe = get_first_executor(f)
+        self.assertIsNone(exe)
+
 class TestUops(unittest.TestCase):
 
     def test_basic_loop(self):
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
index c52c014..d4628f9 100644
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -10,6 +10,7 @@ import io
 import tempfile
 from test import support
 from test.support import os_helper
+from test.support import refleak_helper
 from test.support import socket_helper
 import unittest
 import textwrap
@@ -2443,6 +2444,9 @@ class MiscTestCase(unittest.TestCase):
 
 def tearDownModule():
     support.reap_children()
+    # reap_children may have re-populated caches:
+    if refleak_helper.hunting_for_refleaks():
+        sys._clear_internal_caches()
 
 
 if __name__ == '__main__':