It generates: ```rust #[repr(transparent)] #[derive(Clone)] pub struct Foo(pub id); #[repr(C)] #[derive(Debug, Copy, Clone)] pub struct FooStruct { pub foo: Foo, } ``` So either the interface pointer should derive Copy, Debug and co, or we should prevent structs like that from deriving them. This particular case is a regression from 840b738ec I think, cc @simlay. I'm commenting out the struct in #1953 to have macos CI again.