secp256k1: Derive Copy and Clone

Now that we derive a bunch of traits for the `secp256k1` types that use
`impl_array_newtype` it makes sense to derive `Copy` and `Clone` as
well. This makes the code less surprising because all the impls come
from the same place (the derive attribute).

Note, in `secp256k1-sys` we leave the `Copy` and `Clone` impls in the
macro because there is enough clutter already on the struct definitions
with the fuzzing `cfg_attr`.

src/key.rs

@@ -59,7 +59,7 @@ use crate::Scalar;
 /// ```
 /// [`bincode`]: https://docs.rs/bincode
 /// [`cbor`]: https://docs.rs/cbor
-#[derive(PartialOrd, Ord, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Hash)]
 pub struct SecretKey([u8; constants::SECRET_KEY_SIZE]);
 impl_array_newtype!(SecretKey, u8, constants::SECRET_KEY_SIZE);
 impl_display_secret!(SecretKey);

src/lib.rs

@@ -241,7 +241,7 @@ impl<T: hashes::sha256t::Tag> ThirtyTwoByteHash for hashes::sha256t::Hash<T> {
 }
 
 /// A (hashed) message input to an ECDSA signature.
-#[derive(PartialOrd, Ord, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Hash)]
 pub struct Message([u8; constants::MESSAGE_SIZE]);
 impl_array_newtype!(Message, u8, constants::MESSAGE_SIZE);
 impl_pretty_debug!(Message);

src/macros.rs

@@ -17,8 +17,6 @@
 #[macro_export]
 macro_rules! impl_array_newtype {
     ($thing:ident, $ty:ty, $len:expr) => {
-        impl Copy for $thing {}
-
         impl AsRef<[$ty; $len]> for $thing {
             #[inline]
             /// Gets a reference to the underlying array
@@ -28,14 +26,6 @@ macro_rules! impl_array_newtype {
             }
         }
 
-        impl Clone for $thing {
-            #[inline]
-            fn clone(&self) -> $thing {
-                let &$thing(ref dat) = self;
-                $thing(dat.clone())
-            }
-        }
-
         impl<I> core::ops::Index<I> for $thing
         where
             [$ty]: core::ops::Index<I>,

src/schnorr.rs

@@ -15,7 +15,7 @@ use crate::ffi::{self, CPtr};
 use crate::SECP256K1;
 
 /// Represents a Schnorr signature.
-#[derive(PartialOrd, Ord, PartialEq, Eq, Hash)]
+#[derive(Copy, Clone, PartialOrd, Ord, PartialEq, Eq, Hash)]
 pub struct Signature([u8; constants::SCHNORR_SIGNATURE_SIZE]);
 impl_array_newtype!(Signature, u8, constants::SCHNORR_SIGNATURE_SIZE);
 impl_pretty_debug!(Signature);