error: constant of non-structural type `CustomEq` in a pattern
  --> $DIR/cross-crate-fail.rs:11:9
   |
LL |         consts::SOME => panic!(),
   |         ^^^^^^^^^^^^ constant of non-structural type
   |
  ::: $DIR/auxiliary/consts.rs:1:1
   |
LL | pub struct CustomEq;
   | ------------------- `CustomEq` must be annotated with `#[derive(PartialEq)]` to be usable in patterns
...
LL | pub const SOME: Option<CustomEq> = Some(CustomEq);
   | -------------------------------- constant defined here
   |
   = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details

error: constant of non-structural type `CustomEq` in a pattern
  --> $DIR/cross-crate-fail.rs:17:9
   |
LL |         <Defaulted as consts::AssocConst>::SOME  => panic!(),
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ constant of non-structural type
   |
  ::: $DIR/auxiliary/consts.rs:1:1
   |
LL | pub struct CustomEq;
   | ------------------- `CustomEq` must be annotated with `#[derive(PartialEq)]` to be usable in patterns
...
LL |     const SOME: Option<CustomEq> = Some(CustomEq);
   |     ---------------------------- constant defined here
   |
   = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralPartialEq.html for details

error: aborting due to 2 previous errors