From e56d54e447694c6ced2093d2273c3e3d60b36b6f Mon Sep 17 00:00:00 2001
From: Mark Shannon <mark@hotpy.org>
Date: Fri, 15 Jan 2021 13:52:00 +0000
Subject: Mark instructions at end of class scope as artificial. (GH-24222)

---
 Lib/test/test_sys_settrace.py | 18 ++++++++++++++++++
 Python/compile.c              |  2 ++
 2 files changed, 20 insertions(+)

diff --git a/Lib/test/test_sys_settrace.py b/Lib/test/test_sys_settrace.py
index 4298986..49e8928 100644
--- a/Lib/test/test_sys_settrace.py
+++ b/Lib/test/test_sys_settrace.py
@@ -956,6 +956,24 @@ class TraceTestCase(unittest.TestCase):
              (2, 'line'),
              (2, 'return')])
 
+    def test_implicit_return_in_class(self):
+
+        def func():
+            class A:
+                if 3 < 9:
+                    a = 1
+                else:
+                    a = 2
+
+        self.run_and_compare(func,
+            [(0, 'call'),
+             (1, 'line'),
+             (1, 'call'),
+             (1, 'line'),
+             (2, 'line'),
+             (3, 'line'),
+             (3, 'return'),
+             (1, 'return')])
 
 class SkipLineEventsTraceTestCase(TraceTestCase):
     """Repeat the trace tests, but with per-line events skipped"""
diff --git a/Python/compile.c b/Python/compile.c
index d373d8a..6aa74cc 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -2371,6 +2371,8 @@ compiler_class(struct compiler *c, stmt_ty s)
             compiler_exit_scope(c);
             return 0;
         }
+        /* The following code is artificial */
+        c->u->u_lineno = -1;
         /* Return __classcell__ if it is referenced, otherwise return None */
         if (c->u->u_ste->ste_needs_class_closure) {
             /* Store __classcell__ into class namespace & return it */
-- 
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