error: constant of non-structural type `NoDerive` in a pattern --> $DIR/cant-hide-behind-indirect-struct-param.rs:22:9 | LL | struct NoDerive(#[allow(dead_code)] i32); | --------------- `NoDerive` must be annotated with `#[derive(PartialEq)]` to be usable in patterns ... LL | const WRAP_INDIRECT_PARAM: & &WrapParam = & &WrapParam(NoDerive(0)); | ------------------------------------------------- constant defined here ... LL | WRAP_INDIRECT_PARAM => { panic!("WRAP_INDIRECT_PARAM matched itself"); } | ^^^^^^^^^^^^^^^^^^^ constant of non-structural type | note: the `PartialEq` trait must be derived, manual `impl`s are not sufficient; see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details --> $DIR/cant-hide-behind-indirect-struct-param.rs:11:1 | LL | impl PartialEq for NoDerive { fn eq(&self, _: &Self) -> bool { false } } | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ error: aborting due to 1 previous error