From 0da72df5e92d43d3e1c12097cee350847b5311a9 Mon Sep 17 00:00:00 2001
From: Ayaz Hafiz <ayaz@rwx.com>
Date: Fri, 14 Oct 2022 14:00:01 -0500
Subject: [PATCH] Add ability slice to eq obligation checker

---
 crates/compiler/solve/src/ability.rs | 1 +
 crates/compiler/types/src/subs.rs    | 3 +++
 2 files changed, 4 insertions(+)

diff --git a/crates/compiler/solve/src/ability.rs b/crates/compiler/solve/src/ability.rs
index 8aa9b3a780..95e39a04f8 100644
--- a/crates/compiler/solve/src/ability.rs
+++ b/crates/compiler/solve/src/ability.rs
@@ -1030,6 +1030,7 @@ impl DerivableVisitor for DeriveHash {
 struct DeriveEq;
 impl DerivableVisitor for DeriveEq {
     const ABILITY: Symbol = Symbol::BOOL_EQ;
+    const ABILITY_SLICE: SubsSlice<Symbol> = Subs::AB_EQ;
 
     #[inline(always)]
     fn is_derivable_builtin_opaque(symbol: Symbol) -> bool {
diff --git a/crates/compiler/types/src/subs.rs b/crates/compiler/types/src/subs.rs
index a72d27c4eb..aacc77273c 100644
--- a/crates/compiler/types/src/subs.rs
+++ b/crates/compiler/types/src/subs.rs
@@ -1685,6 +1685,8 @@ impl Subs {
     pub const AB_HASHER: SubsSlice<Symbol>   = SubsSlice::new(2, 1);
     #[rustfmt::skip]
     pub const AB_HASH: SubsSlice<Symbol>     = SubsSlice::new(3, 1);
+    #[rustfmt::skip]
+    pub const AB_EQ: SubsSlice<Symbol>       = SubsSlice::new(4, 1);
 
     pub fn new() -> Self {
         Self::with_capacity(0)
@@ -1708,6 +1710,7 @@ impl Subs {
         symbol_names.push(Symbol::DECODE_DECODING);
         symbol_names.push(Symbol::HASH_HASHER);
         symbol_names.push(Symbol::HASH_HASH_ABILITY);
+        symbol_names.push(Symbol::BOOL_EQ);
 
         let mut subs = Subs {
             utable: UnificationTable::default(),