From d7ea122cf7ff93588f8571fae84ad4091704bf08 Mon Sep 17 00:00:00 2001
From: Calvin Rose <calsrose@gmail.com>
Date: Fri, 4 Mar 2022 19:49:39 -0600
Subject: [PATCH] Fix #928 - Fix hashing of negative 0.

---
 src/core/value.c     | 1 +
 test/suite0011.janet | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/src/core/value.c b/src/core/value.c
index a29c48d0..e742e364 100644
--- a/src/core/value.c
+++ b/src/core/value.c
@@ -322,6 +322,7 @@ int32_t janet_hash(Janet x) {
                 uint64_t u;
             } as;
             as.d = janet_unwrap_number(x);
+            as.d = as.d == 0 ? 0 : as.d; /* normalize negative 0 */
             uint32_t lo = (uint32_t)(as.u & 0xFFFFFFFF);
             uint32_t hi = (uint32_t)(as.u >> 32);
             uint32_t hilo = (hi ^ lo) * 2654435769u;
diff --git a/test/suite0011.janet b/test/suite0011.janet
index 3f23aed0..a4d40495 100644
--- a/test/suite0011.janet
+++ b/test/suite0011.janet
@@ -48,5 +48,7 @@
 
 (assert (= (test) '(1 ())) "issue #919")
 
+(assert (= (hash 0) (hash (* -1 0))) "hash -0 same as hash 0")
+
 (end-suite)