3 files changed, 29 insertions, 6 deletions
diff --git a/compiler/rustc_builtin_macros/src/deriving/bounds.rs b/compiler/rustc_builtin_macros/src/deriving/bounds.rs
index 0481a1189..2c8e6f99c 100644
--- a/compiler/rustc_builtin_macros/src/deriving/bounds.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/bounds.rs
@@ -27,3 +27,26 @@ pub fn expand_deriving_copy(
 
     trait_def.expand(cx, mitem, item, push);
 }
+
+pub fn expand_deriving_const_param_ty(
+    cx: &mut ExtCtxt<'_>,
+    span: Span,
+    mitem: &MetaItem,
+    item: &Annotatable,
+    push: &mut dyn FnMut(Annotatable),
+    is_const: bool,
+) {
+    let trait_def = TraitDef {
+        span,
+        path: path_std!(marker::ConstParamTy),
+        skip_path_as_bound: false,
+        needs_copy_as_bound_if_packed: false,
+        additional_bounds: Vec::new(),
+        supports_unions: false,
+        methods: Vec::new(),
+        associated_types: Vec::new(),
+        is_const,
+    };
+
+    trait_def.expand(cx, mitem, item, push);
+}
diff --git a/compiler/rustc_builtin_macros/src/deriving/clone.rs b/compiler/rustc_builtin_macros/src/deriving/clone.rs
index dfee2d3ce..988356374 100644
--- a/compiler/rustc_builtin_macros/src/deriving/clone.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/clone.rs
@@ -145,7 +145,7 @@ fn cs_clone_simple(
             }
             _ => cx.span_bug(
                 trait_span,
-                &format!("unexpected substructure in simple `derive({})`", name),
+                format!("unexpected substructure in simple `derive({})`", name),
             ),
         }
     }
@@ -179,10 +179,10 @@ fn cs_clone(
             vdata = &variant.data;
         }
         EnumTag(..) | AllFieldlessEnum(..) => {
-            cx.span_bug(trait_span, &format!("enum tags in `derive({})`", name,))
+            cx.span_bug(trait_span, format!("enum tags in `derive({})`", name,))
         }
         StaticEnum(..) | StaticStruct(..) => {
-            cx.span_bug(trait_span, &format!("associated function in `derive({})`", name))
+            cx.span_bug(trait_span, format!("associated function in `derive({})`", name))
         }
     }
 
@@ -194,7 +194,7 @@ fn cs_clone(
                     let Some(ident) = field.name else {
                         cx.span_bug(
                             trait_span,
-                            &format!("unnamed field in normal struct in `derive({})`", name,),
+                            format!("unnamed field in normal struct in `derive({})`", name,),
                         );
                     };
                     let call = subcall(cx, field);
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
index e5a003315..4ba09335c 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
@@ -1038,7 +1038,7 @@ impl<'a> MethodDef<'a> {
     /// `&self.x` because that might cause an unaligned ref. So for any trait
     /// method that takes a reference, we use a local block to force a copy.
     /// This requires that the field impl `Copy`.
-    /// ```
+    /// ```rust,ignore (example)
     /// # struct A { x: u8, y: u8 }
     /// impl PartialEq for A {
     ///     fn eq(&self, other: &A) -> bool {
@@ -1591,7 +1591,7 @@ impl<'a> TraitDef<'a> {
                                 BYTE_SLICE_IN_PACKED_STRUCT_WITH_DERIVE,
                                 sp,
                                 ast::CRATE_NODE_ID,
-                                &format!(
+                                format!(
                                     "{} slice in a packed struct that derives a built-in trait",
                                     ty
                                 ),