diff --git a/Lib/modulefinder.py b/Lib/modulefinder.py
--- a/Lib/modulefinder.py
+++ b/Lib/modulefinder.py
@@ -563,21 +563,23 @@ class ModuleFinder:
                                     % (original_filename,))
             self.processed_paths.append(original_filename)
 
         consts = list(co.co_consts)
         for i in range(len(consts)):
             if isinstance(consts[i], type(co)):
                 consts[i] = self.replace_paths_in_code(consts[i])
 
-        return types.CodeType(co.co_argcount, co.co_nlocals, co.co_stacksize,
-                         co.co_flags, co.co_code, tuple(consts), co.co_names,
-                         co.co_varnames, new_filename, co.co_name,
-                         co.co_firstlineno, co.co_lnotab,
-                         co.co_freevars, co.co_cellvars)
+        return types.CodeType(co.co_argcount, co.co_kwonlyargcount,
+                              co.co_nlocals, co.co_stacksize,
+                              co.co_flags, co.co_code, tuple(consts),
+                              co.co_names, co.co_varnames,
+                              new_filename, co.co_name,
+                              co.co_firstlineno, co.co_lnotab,
+                              co.co_freevars, co.co_cellvars)
 
 
 def test():
     # Parse command line
     import getopt
     try:
         opts, args = getopt.getopt(sys.argv[1:], "dmp:qx:")
     except getopt.error as msg:
diff --git a/Lib/test/test_modulefinder.py b/Lib/test/test_modulefinder.py
--- a/Lib/test/test_modulefinder.py
+++ b/Lib/test/test_modulefinder.py
@@ -240,21 +240,22 @@ def create_package(source):
                     ofi.close()
                 ofi = open_file(os.path.join(TEST_DIR, line.strip()))
     finally:
         if ofi:
             ofi.close()
 
 
 class ModuleFinderTest(unittest.TestCase):
-    def _do_test(self, info, report=False):
+    def _do_test(self, info, report=False, debug=0, replace_paths=[]):
         import_this, modules, missing, maybe_missing, source = info
         create_package(source)
         try:
-            mf = modulefinder.ModuleFinder(path=TEST_PATH)
+            mf = modulefinder.ModuleFinder(path=TEST_PATH, debug=debug,
+                                           replace_paths=replace_paths)
             mf.import_hook(import_this)
             if report:
                 mf.report()
 ##                # This wouldn't work in general when executed several times:
 ##                opath = sys.path[:]
 ##                sys.path = TEST_PATH
 ##                try:
 ##                    __import__(import_this)
@@ -303,14 +304,24 @@ class ModuleFinderTest(unittest.TestCase
         source_path = base_path + importlib.machinery.SOURCE_SUFFIXES[0]
         bytecode_path = base_path + importlib.machinery.BYTECODE_SUFFIXES[0]
         with open_file(source_path) as file:
             file.write('testing_modulefinder = True\n')
         py_compile.compile(source_path, cfile=bytecode_path)
         os.remove(source_path)
         self._do_test(bytecode_test)
 
+    def test_replace_paths(self):
+        old_path = os.path.join(TEST_DIR, 'a', 'module.py')
+        new_path = os.path.join(TEST_DIR, 'a', 'spam.py')
+        with support.captured_stdout() as output:
+            self._do_test(maybe_test, debug=2,
+                          replace_paths=[(old_path, new_path)])
+        output = output.getvalue()
+        expected = "co_filename '%s' changed to '%s'" % (old_path, new_path)
+        self.assertIn(expected, output)
+
 
 def test_main():
     support.run_unittest(ModuleFinderTest)
 
 if __name__ == "__main__":
     unittest.main()