From 5967e812a2a887f44fb49443f06e1fac5cf4e916 Mon Sep 17 00:00:00 2001
From: Jacob Lifshay <programmerjake@gmail.com>
Date: Tue, 8 Apr 2025 21:52:47 -0700
Subject: [PATCH] fix [SU]IntValue's PartialEq for interning

different widths must make values compare not equal otherwise interning
will e.g. substitute a 0x0_u8 for a 0x0_u2
---
 crates/fayalite/src/int.rs       | 31 +++++++++++++++----------------
 crates/fayalite/src/sim/value.rs |  8 ++++----
 2 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/crates/fayalite/src/int.rs b/crates/fayalite/src/int.rs
index 053bd1d..d8364b1 100644
--- a/crates/fayalite/src/int.rs
+++ b/crates/fayalite/src/int.rs
@@ -765,7 +765,7 @@ macro_rules! impl_int {
             }
         }
 
-        #[derive(Clone, Eq, Hash)]
+        #[derive(Clone, PartialEq, Eq, Hash)]
         pub struct $value<Width: Size = DynSize> {
             bits: Arc<BitVec>,
             _phantom: PhantomData<Width>,
@@ -811,24 +811,15 @@ macro_rules! impl_int {
             }
         }
 
-        impl<LhsWidth: Size, RhsWidth: Size> PartialEq<$value<RhsWidth>> for $value<LhsWidth> {
-            fn eq(&self, other: &$value<RhsWidth>) -> bool {
-                self.to_bigint() == other.to_bigint()
-            }
-        }
-
-        impl<LhsWidth: Size, RhsWidth: Size> PartialOrd<$value<RhsWidth>> for $value<LhsWidth> {
-            fn partial_cmp(&self, other: &$value<RhsWidth>) -> Option<std::cmp::Ordering> {
+        impl<Width: Size> PartialOrd for $value<Width> {
+            fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
+                if self.width() != other.width() {
+                    return None;
+                }
                 Some(self.to_bigint().cmp(&other.to_bigint()))
             }
         }
 
-        impl<Width: Size> Ord for $value<Width> {
-            fn cmp(&self, other: &Self) -> std::cmp::Ordering {
-                self.to_bigint().cmp(&other.to_bigint())
-            }
-        }
-
         impl<Width: Size> From<$value<Width>> for BigInt {
             fn from(v: $value<Width>) -> BigInt {
                 v.to_bigint()
@@ -1069,7 +1060,8 @@ pub trait BoolOrIntType: Type + sealed::BoolOrIntTypeSealed {
     type Width: Size;
     type Signed: GenericConstBool;
     type Value: Clone
-        + Ord
+        + PartialOrd
+        + Eq
         + std::hash::Hash
         + fmt::Debug
         + fmt::Display
@@ -1300,6 +1292,13 @@ impl ToLiteralBits for bool {
 mod tests {
     use super::*;
 
+    #[test]
+    fn test_different_value_widths_compare_ne() {
+        // interning relies on [SU]IntValue with different `width` comparing not equal
+        assert_ne!(UInt[3].from_int_wrapping(0), UInt[4].from_int_wrapping(0));
+        assert_ne!(SInt[3].from_int_wrapping(0), SInt[4].from_int_wrapping(0));
+    }
+
     #[test]
     fn test_uint_for_value() {
         assert_eq!(UInt::for_value(0u8).width, 0);
diff --git a/crates/fayalite/src/sim/value.rs b/crates/fayalite/src/sim/value.rs
index 737043a..8dace78 100644
--- a/crates/fayalite/src/sim/value.rs
+++ b/crates/fayalite/src/sim/value.rs
@@ -324,14 +324,14 @@ impl<T: SimValuePartialEq<U>, U: Type> PartialEq<SimValue<U>> for SimValue<T> {
     }
 }
 
-impl<LhsWidth: Size, RhsWidth: Size> SimValuePartialEq<UIntType<RhsWidth>> for UIntType<LhsWidth> {
-    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<UIntType<RhsWidth>>) -> bool {
+impl<Width: Size> SimValuePartialEq<Self> for UIntType<Width> {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<Self>) -> bool {
         **this == **other
     }
 }
 
-impl<LhsWidth: Size, RhsWidth: Size> SimValuePartialEq<SIntType<RhsWidth>> for SIntType<LhsWidth> {
-    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<SIntType<RhsWidth>>) -> bool {
+impl<Width: Size> SimValuePartialEq<Self> for SIntType<Width> {
+    fn sim_value_eq(this: &SimValue<Self>, other: &SimValue<Self>) -> bool {
         **this == **other
     }
 }