Use hash-code-combine and type-tag in hash_code

racket · Feb 6, 2023 · 06ef3ec · 06ef3ec
1 parent f8020a0
commit 06ef3ec
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Showing 2 changed files with 12 additions and 4 deletions.
diff --git a/rhombus/data/equality.rhm b/rhombus/data/equality.rhm
@@ -9,6 +9,8 @@ import:
   lib("racket/base.rkt"):
     meta
     expose: #{generate-temporaries}
+  lib("racket/base.rkt").#{eq-hash-code}
+  lib("racket/hash-code.rkt").#{hash-code-combine}
   lib("racket/unsafe/ops.rkt").#{unsafe-fx+/wraparound}
   lib("racket/unsafe/ops.rkt").#{unsafe-fx*/wraparound}
 
@@ -26,10 +28,8 @@ 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: #{hash-code-combine}(code, recur(this . $key_id()))
      ...
      code'
 

diff --git 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
@@ -82,3 +85,8 @@ check:
   use_dynamic
   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