1 files changed, 18 insertions, 0 deletions
diff --git a/Lib/test/test_scope.py b/Lib/test/test_scope.py
index cd2d98c..3914ed0 100644
--- a/Lib/test/test_scope.py
+++ b/Lib/test/test_scope.py
@@ -519,6 +519,24 @@ self.assert_(X.passed)
         self.assert_("x" not in varnames)
         self.assert_("y" in varnames)
 
+    def testLocalsClass_WithTrace(self):
+        # Issue23728: after the trace function returns, the locals()
+        # dictionary is used to update all variables, this used to
+        # include free variables. But in class statements, free
+        # variables are not inserted...
+        import sys
+        sys.settrace(lambda a,b,c:None)
+        try:
+            x = 12
+
+            class C:
+                def f(self):
+                    return x
+
+            assert x == 12 # Used to raise UnboundLocalError
+        finally:
+            sys.settrace(None)
+
     def testBoundAndFree(self):
         # var is bound and free in class