diff --git a/tests/check_new_syntax.py b/tests/check_new_syntax.py
index 427db4ebd..7e1387c45 100755
--- a/tests/check_new_syntax.py
+++ b/tests/check_new_syntax.py
@@ -44,6 +44,8 @@ def check_new_syntax(tree: ast.AST, path: Path, stub: str) -> list[str]:
     class OldSyntaxFinder(ast.NodeVisitor):
         def visit_AnnAssign(self, node: ast.AnnAssign) -> None:
             AnnotationUnionFinder().visit(node.annotation)
+            if node.value is not None:
+                NonAnnotationUnionFinder().visit(node.value)
             self.generic_visit(node)
 
         def visit_arg(self, node: ast.arg) -> None: