diff --git a/crates/objc2/src/runtime/nscopying.rs b/crates/objc2/src/runtime/nscopying.rs
index 5ea023f9c..94cb0f02e 100644
--- a/crates/objc2/src/runtime/nscopying.rs
+++ b/crates/objc2/src/runtime/nscopying.rs
@@ -9,10 +9,11 @@ pub trait Copyhelper<T: ?Sized> {
     type CopyOutput: ?Sized + Message;
     type MutableCopyOutput: ?Sized + Message;
 
+    // TODO: Use this to autogenerate `ToOwned` impls
     #[doc(hidden)]
     fn __do_copy(t: &T) -> Id<T>;
 }
-impl<T: ClassType + NSCopying + Message<Kind = Unknown>> Copyhelper<T> for Unknown {
+impl<T: NSCopying + Message<Kind = Unknown>> Copyhelper<T> for Unknown {
     type CopyOutput = T;
     type MutableCopyOutput = T;
 
@@ -21,7 +22,7 @@ impl<T: ClassType + NSCopying + Message<Kind = Unknown>> Copyhelper<T> for Unkno
         t.copy()
     }
 }
-impl<T: ClassType + NSCopying + Message<Kind = Immutable>> Copyhelper<T> for Immutable {
+impl<T: NSCopying + Message<Kind = Immutable>> Copyhelper<T> for Immutable {
     type CopyOutput = T;
     type MutableCopyOutput = T;
 
@@ -30,7 +31,7 @@ impl<T: ClassType + NSCopying + Message<Kind = Immutable>> Copyhelper<T> for Imm
         t.copy()
     }
 }
-impl<T: ClassType + NSCopying + Message<Kind = Mutable>> Copyhelper<T> for Mutable {
+impl<T: NSCopying + Message<Kind = Mutable>> Copyhelper<T> for Mutable {
     type CopyOutput = T;
     type MutableCopyOutput = T;
 
@@ -41,8 +42,8 @@ impl<T: ClassType + NSCopying + Message<Kind = Mutable>> Copyhelper<T> for Mutab
 }
 impl<T, S> Copyhelper<T> for ImmutableWithMutableSubclass<S>
 where
-    T: ClassType + NSCopying + Message<Kind = ImmutableWithMutableSubclass<S>>,
-    S: ClassType + Message<Kind = MutableWithImmutableSuperclass<T>>,
+    T: NSCopying + Message<Kind = ImmutableWithMutableSubclass<S>>,
+    S: Message<Kind = MutableWithImmutableSuperclass<T>>,
 {
     type CopyOutput = T;
     type MutableCopyOutput = S;
@@ -54,8 +55,8 @@ where
 }
 impl<T, S> Copyhelper<T> for MutableWithImmutableSuperclass<S>
 where
-    T: ClassType + NSMutableCopying + Message<Kind = MutableWithImmutableSuperclass<S>>,
-    S: ClassType + Message<Kind = ImmutableWithMutableSubclass<T>>,
+    T: NSMutableCopying + Message<Kind = MutableWithImmutableSuperclass<S>>,
+    S: Message<Kind = ImmutableWithMutableSubclass<T>>,
 {
     type CopyOutput = S;
     type MutableCopyOutput = T;
@@ -65,7 +66,7 @@ where
         t.mutableCopy()
     }
 }
-impl<T: ClassType + NSCopying + Message<Kind = InteriorMutable>> Copyhelper<T> for InteriorMutable {
+impl<T: NSCopying + Message<Kind = InteriorMutable>> Copyhelper<T> for InteriorMutable {
     type CopyOutput = T;
     type MutableCopyOutput = T;
 
@@ -74,7 +75,7 @@ impl<T: ClassType + NSCopying + Message<Kind = InteriorMutable>> Copyhelper<T> f
         t.copy()
     }
 }
-impl<T: ClassType + NSCopying + Message<Kind = MainThreadOnly>> Copyhelper<T> for MainThreadOnly {
+impl<T: NSCopying + Message<Kind = MainThreadOnly>> Copyhelper<T> for MainThreadOnly {
     type CopyOutput = T;
     type MutableCopyOutput = T;
 
@@ -100,7 +101,7 @@ pub unsafe trait NSCopying {
     /// `NSString`.
     fn copy(&self) -> Id<<Self::Kind as Copyhelper<Self>>::CopyOutput>
     where
-        Self: Sized + ClassType,
+        Self: Sized + Message,
         Self::Kind: Copyhelper<Self>,
     {
         unsafe { msg_send_id![self, copy] }
@@ -132,9 +133,10 @@ crate::__inner_extern_protocol!(
 /// - The `mutableCopy` selector must return an owned object.
 /// - TODO: More.
 pub unsafe trait NSMutableCopying {
+    #[allow(non_snake_case)]
     fn mutableCopy(&self) -> Id<<Self::Kind as Copyhelper<Self>>::MutableCopyOutput>
     where
-        Self: Sized + ClassType,
+        Self: Sized + Message,
         Self::Kind: Copyhelper<Self>,
     {
         unsafe { msg_send_id![self, mutableCopy] }