Allow creation of UniquePtrs to trivial aliased types.
diff --git a/tests/ffi/lib.rs b/tests/ffi/lib.rs
index 7cffded..f80cda7 100644
--- a/tests/ffi/lib.rs
+++ b/tests/ffi/lib.rs
@@ -14,15 +14,23 @@
     use cxx::kind::{Opaque, Trivial};
     use cxx::{type_id, CxxString, ExternType};
 
+    // Trivial.
     #[repr(C)]
     pub struct D {
-        d: u64,
+        pub d: u64,
     }
 
+    // Opaque, and has realistic complexity.
     #[repr(C)]
     pub struct E {
-        e: u64,
         e_str: CxxString,
+        e: u64,
+    }
+
+    // Opaque, but simple enough that bad code can try to create it.
+    #[repr(C)]
+    pub struct F {
+        pub f: u64,
     }
 
     unsafe impl ExternType for D {
@@ -34,6 +42,11 @@
         type Id = type_id!("tests::E");
         type Kind = Opaque;
     }
+
+    unsafe impl ExternType for F {
+        type Id = type_id!("tests::F");
+        type Kind = Opaque;
+    }
 }
 
 #[cxx::bridge(namespace = tests)]