chore: checkpoint before Python removal

vendor/pin-project/tests/run-pass/private_in_public-enum.rs

@@ -0,0 +1,25 @@
+// SPDX-License-Identifier: Apache-2.0 OR MIT
+
+// Even if allows private_in_public, these are errors.
+
+#![allow(private_interfaces, dead_code)]
+
+pub enum PublicEnum {
+    V(PrivateEnum), //~ ERROR E0446
+}
+
+enum PrivateEnum {
+    V(u8),
+}
+
+mod foo {
+    pub(crate) enum CrateEnum {
+        V(PrivateEnum), //~ ERROR E0446
+    }
+
+    enum PrivateEnum {
+        V(u8),
+    }
+}
+
+fn main() {}