From d99f1511ebded582dd440dcbbf2c19b8d7236f1d Mon Sep 17 00:00:00 2001
From: Intege-rs <me@jessiep.me>
Date: Tue, 3 Feb 2026 03:39:43 -0500
Subject: [PATCH] fix enum discriminants not being included in the hash

---
 hash2_derive/src/lib.rs |  8 +++++++-
 tests/derive_test.rs    | 23 +++++++++++++++++++++++
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/hash2_derive/src/lib.rs b/hash2_derive/src/lib.rs
index e1a6d8d..c5f1e52 100644
--- a/hash2_derive/src/lib.rs
+++ b/hash2_derive/src/lib.rs
@@ -35,6 +35,11 @@ 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);
+            };
+            
             let variants = data.variants.iter().map(|variant| {
                 let variant_name = &variant.ident;
                 match &variant.fields {
@@ -69,8 +74,9 @@ pub fn derive_hash2(input: TokenStream) -> TokenStream {
                     }
                 }
             });
-            
+           
             quote! {
+                #discriminant_hash
                 match self {
                     #(#variants)*
                 }
diff --git a/tests/derive_test.rs b/tests/derive_test.rs
index 2675d4c..f7017ea 100644
--- a/tests/derive_test.rs
+++ b/tests/derive_test.rs
@@ -1,3 +1,4 @@
+use std::hash::{Hash, Hasher};
 use hash2::Hash2;
 
 #[derive(Hash2)]
@@ -49,6 +50,13 @@ where
     ref2: &'b str,
 }
 
+#[derive(Hash2)]
+enum ScalerEnum {
+    A,
+    B,
+    C,
+}
+
 #[derive(Hash2)]
 enum SimpleEnum {
     A,
@@ -141,6 +149,21 @@ fn test_complex() {
     let _ = hash_value(&s);
 }
 
+#[test]
+fn test_scaler_enum() {
+    let e1 = ScalerEnum::A;
+    let e2 = ScalerEnum::B;
+    let e3 = ScalerEnum::C;
+
+    let a = hash_value(&e1);
+    let b = hash_value(&e2);
+    let c = hash_value(&e3);
+    assert_ne!(a, b);
+    assert_ne!(a, c);
+    assert_ne!(b, c);
+}
+
+
 #[test]
 fn test_simple_enum() {
     let e1 = SimpleEnum::A;