chore: checkpoint before Python removal

vendor/darling/tests/compile-fail/flatten_meta_conflicts.rs

@@ -0,0 +1,21 @@
+use darling::FromMeta;
+
+#[derive(FromMeta)]
+struct Inner {
+    left: String,
+    right: String,
+}
+
+#[derive(FromMeta)]
+struct Outer {
+    #[darling(flatten, multiple, with = demo, skip = true)]
+    field: Inner,
+}
+
+#[derive(FromMeta)]
+struct ThisIsFine {
+    #[darling(flatten, multiple = false)]
+    field: Inner,
+}
+
+fn main() {}