Rollup merge of #111649 - Nilstrieb:derive-const-param-ty, r=BoxyUwU

Add derive for `core::marker::ConstParamTy`

This makes it easier to implement it for a type, just like `Copy`.

`@BoxyUwU` half asked me to add it

1 files changed, 11 insertions, 1 deletions

diff --git a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr
index ca5abf5e254..52701d55914 100644
--- a/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr
+++ b/tests/ui/const-generics/adt_const_params/const_param_ty_impl_no_structural_eq.stderr
@@ -7,6 +7,16 @@ LL | impl std::marker::ConstParamTy for CantParam {}
 note: required by a bound in `ConstParamTy`
   --> $SRC_DIR/core/src/marker.rs:LL:COL
 
-error: aborting due to previous error
+error[E0277]: the type `CantParamDerive` does not `#[derive(Eq)]`
+  --> $DIR/const_param_ty_impl_no_structural_eq.rs:13:10
+   |
+LL | #[derive(std::marker::ConstParamTy)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `StructuralEq` is not implemented for `CantParamDerive`
+   |
+note: required by a bound in `ConstParamTy`
+  --> $SRC_DIR/core/src/marker.rs:LL:COL
+   = note: this error originates in the derive macro `std::marker::ConstParamTy` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0277`.