error: to use a constant of type `MyType` in a pattern, `MyType` must be annotated with `#[derive(PartialEq, Eq)]`
  --> $DIR/const-partial_eq-fallback-ice.rs:14:12
   |
LL |     if let CONSTANT = &&MyType {
   |            ^^^^^^^^
   |
   = note: the traits must be derived, manual `impl`s are not sufficient
   = note: see https://doc.rust-lang.org/stable/std/marker/trait.StructuralEq.html for details

error: aborting due to previous error