From 2026002c216c52b0be849320046013ea98a55c76 Mon Sep 17 00:00:00 2001
From: AlexKnauth <alexander@knauth.org>
Date: Tue, 7 Feb 2023 11:22:17 -0500
Subject: [PATCH] Use hash_code_combine and type-tag in hash_code

---
 rhombus/data/equality.rhm   | 9 +++------
 rhombus/tests/equatable.rhm | 8 ++++++++
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/rhombus/data/equality.rhm b/rhombus/data/equality.rhm
index e44635883..e429c41aa 100644
--- a/rhombus/data/equality.rhm
+++ b/rhombus/data/equality.rhm
@@ -9,8 +9,7 @@ import:
   lib("racket/base.rkt"):
     meta
     expose: #{generate-temporaries}
-  lib("racket/unsafe/ops.rkt").#{unsafe-fx+/wraparound}
-  lib("racket/unsafe/ops.rkt").#{unsafe-fx*/wraparound}
+  lib("racket/base.rkt").#{eq-hash-code}
 
 
 class_clause.macro 'equality: $key_expr; ...':
@@ -26,10 +25,8 @@ class_clause.macro 'equality: $key_expr; ...':
        $('&& (recur(this . $key_id(), (other :~ PrivateForEquals) . $key_id()))') ...
 
    private override method hash_code(recur):
-     let code = 1000003
-     let code:
-       #{unsafe-fx+/wraparound}(
-         #{unsafe-fx*/wraparound}(code, 31), recur(this . $key_id()))
+     let code = #{eq-hash-code}(PrivateForEquals)
+     let code: Equatable.hash_code_combine(code, recur(this . $key_id()))
      ...
      code'
 
diff --git a/rhombus/tests/equatable.rhm b/rhombus/tests/equatable.rhm
index 094ce0036..7b84ef6c1 100644
--- a/rhombus/tests/equatable.rhm
+++ b/rhombus/tests/equatable.rhm
@@ -24,6 +24,9 @@ class Fail():
 class OrderedTriple(fst, snd, thd):
   equality: fst; snd; thd
 
+class OrderedTriple2(fst, snd, thd):
+  equality: fst; snd; thd
+
 check AnythingGoes() == AnythingGoes() ~is #true
 check:
   use_dynamic
@@ -83,6 +86,11 @@ check:
   OrderedTriple("A", "B", "C").hash_code(fun (_): 0)
   ~raises "hash_code: no such field or method"
 
+check: OrderedTriple("A", "B", "C") == OrderedTriple2("A", "B", "C") ~is #false
+check: hc(OrderedTriple("A", "B", "C")) == hc(OrderedTriple2("A", "B", "C"))
+       ~is #false
+check: {OrderedTriple("A", "B", "C"), OrderedTriple2("A", "B", "C")}.length() ~is 2
+
 class Foo(a, b, c):
   equality:
     a