Add serialization for empty tuples

CHANGELOG.md

@@ -1,4 +1,3 @@
-
 ## Pending
 
 The main features of this release are:
@@ -59,6 +58,7 @@ The main features of this release are:
 - #144 (ark-poly) Add serialization for polynomials and evaluations
 - #149 (ark-serialize) Add an impl of `CanonicalSerialize/Deserialize` for `String`.
 - #153 (ark-serialize) Add an impl of `CanonicalSerialize/Deserialize` for `Rc<T>`.
+- #158 (ark-serialize) Add an impl of `CanonicalSerialize/Deserialize` for `()`.
 
 ### Bug fixes
 - #36 (ark-ec) In Short-Weierstrass curves, include an infinity bit in `ToConstraintField`.

serialize/src/lib.rs

@@ -352,13 +352,13 @@ pub const fn buffer_byte_size(modulus_bits: usize) -> usize {
 
 // Implement Serialization for tuples
 macro_rules! impl_tuple {
-    ($( $ty: ident : $no: tt, )+) => {
-        impl<$($ty, )+> CanonicalSerialize for ($($ty,)+) where
-            $($ty: CanonicalSerialize,)+
+    ($( $ty: ident : $no: tt, )*) => {
+        impl<$($ty, )*> CanonicalSerialize for ($($ty,)*) where
+            $($ty: CanonicalSerialize,)*
         {
             #[inline]
-            fn serialize<W: Write>(&self, mut writer: W) -> Result<(), SerializationError> {
-                $(self.$no.serialize(&mut writer)?;)*
+            fn serialize<W: Write>(&self, mut _writer: W) -> Result<(), SerializationError> {
+                $(self.$no.serialize(&mut _writer)?;)*
                 Ok(())
             }
 
@@ -370,14 +370,14 @@ macro_rules! impl_tuple {
             }
 
             #[inline]
-            fn serialize_uncompressed<W: Write>(&self, mut writer: W) -> Result<(), SerializationError> {
-                $(self.$no.serialize_uncompressed(&mut writer)?;)*
+            fn serialize_uncompressed<W: Write>(&self, mut _writer: W) -> Result<(), SerializationError> {
+                $(self.$no.serialize_uncompressed(&mut _writer)?;)*
                 Ok(())
             }
 
             #[inline]
-            fn serialize_unchecked<W: Write>(&self, mut writer: W) -> Result<(), SerializationError> {
-                $(self.$no.serialize_unchecked(&mut writer)?;)*
+            fn serialize_unchecked<W: Write>(&self, mut _writer: W) -> Result<(), SerializationError> {
+                $(self.$no.serialize_unchecked(&mut _writer)?;)*
                 Ok(())
             }
 
@@ -389,33 +389,34 @@ macro_rules! impl_tuple {
             }
         }
 
-        impl<$($ty, )+> CanonicalDeserialize for ($($ty,)+) where
-            $($ty: CanonicalDeserialize,)+
+        impl<$($ty, )*> CanonicalDeserialize for ($($ty,)*) where
+            $($ty: CanonicalDeserialize,)*
         {
             #[inline]
-            fn deserialize<R: Read>(mut reader: R) -> Result<Self, SerializationError> {
+            fn deserialize<R: Read>(mut _reader: R) -> Result<Self, SerializationError> {
                 Ok(($(
-                    $ty::deserialize(&mut reader)?,
-                )+))
+                    $ty::deserialize(&mut _reader)?,
+                )*))
             }
 
             #[inline]
-            fn deserialize_uncompressed<R: Read>(mut reader: R) -> Result<Self, SerializationError> {
+            fn deserialize_uncompressed<R: Read>(mut _reader: R) -> Result<Self, SerializationError> {
                 Ok(($(
-                    $ty::deserialize_uncompressed(&mut reader)?,
-                )+))
+                    $ty::deserialize_uncompressed(&mut _reader)?,
+                )*))
             }
 
             #[inline]
-            fn deserialize_unchecked<R: Read>(mut reader: R) -> Result<Self, SerializationError> {
+            fn deserialize_unchecked<R: Read>(mut _reader: R) -> Result<Self, SerializationError> {
                 Ok(($(
-                    $ty::deserialize_unchecked(&mut reader)?,
-                )+))
+                    $ty::deserialize_unchecked(&mut _reader)?,
+                )*))
             }
         }
     }
 }
 
+impl_tuple!();
 impl_tuple!(A:0, B:1,);
 impl_tuple!(A:0, B:1, C:2,);
 impl_tuple!(A:0, B:1, C:2, D:3,);
@@ -967,6 +968,8 @@ mod test {
 
     #[test]
     fn test_tuple() {
+        test_serialize(());
+        test_serialize((123u64, Dummy));
         test_serialize((123u64, 234u32, Dummy));
     }