From 79101edb03b7381b514126c68acabfcbbba2f842 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Wed, 13 Sep 2023 09:00:15 -0700
Subject: gh-109351: Fix crash when compiling AST with invalid NamedExpr
 (#109352)

---
 Lib/test/test_compile.py                           | 27 ++++++++++++++++++++++
 .../2023-09-12-16-00-42.gh-issue-109351.kznGeR.rst |  2 ++
 Python/ast.c                                       |  5 ++++
 3 files changed, 34 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Core and Builtins/2023-09-12-16-00-42.gh-issue-109351.kznGeR.rst

diff --git a/Lib/test/test_compile.py b/Lib/test/test_compile.py
index a8a519f..fa74455 100644
--- a/Lib/test/test_compile.py
+++ b/Lib/test/test_compile.py
@@ -443,6 +443,33 @@ class TestSpecifics(unittest.TestCase):
         self.assertIn("_A__mangled_mod", A.f.__code__.co_varnames)
         self.assertIn("__package__", A.f.__code__.co_varnames)
 
+    def test_compile_invalid_namedexpr(self):
+        # gh-109351
+        m = ast.Module(
+            body=[
+                ast.Expr(
+                    value=ast.ListComp(
+                        elt=ast.NamedExpr(
+                            target=ast.Constant(value=1),
+                            value=ast.Constant(value=3),
+                        ),
+                        generators=[
+                            ast.comprehension(
+                                target=ast.Name(id="x", ctx=ast.Store()),
+                                iter=ast.Name(id="y", ctx=ast.Load()),
+                                ifs=[],
+                                is_async=0,
+                            )
+                        ],
+                    )
+                )
+            ],
+            type_ignores=[],
+        )
+
+        with self.assertRaisesRegex(TypeError, "NamedExpr target must be a Name"):
+            compile(ast.fix_missing_locations(m), "<file>", "exec")
+
     def test_compile_ast(self):
         fname = __file__
         if fname.lower().endswith('pyc'):
diff --git a/Misc/NEWS.d/next/Core and Builtins/2023-09-12-16-00-42.gh-issue-109351.kznGeR.rst b/Misc/NEWS.d/next/Core and Builtins/2023-09-12-16-00-42.gh-issue-109351.kznGeR.rst
new file mode 100644
index 0000000..23b81c1
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2023-09-12-16-00-42.gh-issue-109351.kznGeR.rst	
@@ -0,0 +1,2 @@
+Fix crash when compiling an invalid AST involving a named (walrus)
+expression.
diff --git a/Python/ast.c b/Python/ast.c
index 21cb38f..a230c7e 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -381,6 +381,11 @@ validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
         ret = validate_exprs(state, exp->v.Tuple.elts, ctx, 0);
         break;
     case NamedExpr_kind:
+        if (exp->v.NamedExpr.target->kind != Name_kind) {
+            PyErr_SetString(PyExc_TypeError,
+                            "NamedExpr target must be a Name");
+            return 0;
+        }
         ret = validate_expr(state, exp->v.NamedExpr.value, Load);
         break;
     /* This last case doesn't have any checking. */
-- 
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