checkpoint

hash2_derive/src/lib.rs

@@ -37,7 +37,7 @@ pub fn derive_hash2(input: TokenStream) -> TokenStream {
         Data::Enum(data) => {
             // Hash the discriminant first to ensure different variants hash differently
             let discriminant_hash = quote! {
-                core::mem::discriminant(self).hash(state);
+                core::hash::Hash::hash(&core::mem::discriminant(self), state);
             };
             
             let variants = data.variants.iter().map(|variant| {

src/lib.rs

@@ -11,7 +11,7 @@ pub trait Hash2 {
 #[cfg(feature = "uuid")]
 impl Hash2 for uuid::Uuid {
     fn hash<H: Hasher>(&self, state: &mut H) {
-        let (a,b) = self.as_u64_pair();
+        let (a, b) = self.as_u64_pair();
         state.write_u64(a);
         state.write_u64(b);
     }
@@ -118,6 +118,15 @@ impl Hash2 for String {
     }
 }
 
+impl<T: ?Sized> Hash2 for std::borrow::Cow<'_, T>
+where
+    T: Hash2 + ToOwned,
+{
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        Hash2::hash(&**self, state)
+    }
+}
+
 impl<T: Hash2 + ?Sized> Hash2 for &T {
     fn hash<H: Hasher>(&self, state: &mut H) {
         (*self).hash(state);
@@ -153,6 +162,12 @@ impl<T: Hash2> Hash2 for Vec<T> {
     }
 }
 
+impl<T: Hash2> Hash2 for Box<T> {
+    fn hash<H: Hasher>(&self, state: &mut H) {
+        T::hash(&**self, state)
+    }
+}
+
 impl<T: Hash2> Hash2 for Option<T> {
     fn hash<H: Hasher>(&self, state: &mut H) {
         match self {

tests/derive_test.rs

@@ -1,4 +1,3 @@
-use std::hash::{Hash, Hasher};
 use hash2::Hash2;
 
 #[derive(Hash2)]
@@ -185,3 +184,33 @@ fn test_generic_enum() {
     let _ = hash_value(&e2);
     let _ = hash_value(&e3);
 }
+
+#[test]
+fn test_cow_tuple_slice() {
+    use std::borrow::Cow;
+    
+    // Test Cow<[T]> where T is a tuple
+    let data = vec![("key1", 1u32), ("key2", 2u32)];
+    let cow_borrowed: Cow<[(&str, u32)]> = Cow::Borrowed(&data);
+    let cow_owned: Cow<[(&str, u32)]> = Cow::Owned(data.clone());
+    
+    let hash1 = hash_value(&cow_borrowed);
+    let hash2 = hash_value(&cow_owned);
+    assert_eq!(hash1, hash2, "Borrowed and owned Cow should hash the same");
+    
+    // Test with nested Option
+    let with_option: Option<Cow<[(&str, u32)]>> = Some(Cow::Borrowed(&data));
+    let _ = hash_value(&with_option);
+}
+
+#[test]
+fn test_cow_str() {
+    use std::borrow::Cow;
+    
+    let borrowed: Cow<str> = Cow::Borrowed("hello");
+    let owned: Cow<str> = Cow::Owned(String::from("hello"));
+    
+    let hash1 = hash_value(&borrowed);
+    let hash2 = hash_value(&owned);
+    assert_eq!(hash1, hash2, "Borrowed and owned str Cow should hash the same");
+}