From 45ecd6a99689dbb200342bb576f75a1930455e02 Mon Sep 17 00:00:00 2001
From: Matthew Lugg <mlugg@mlugg.co.uk>
Date: Wed, 6 May 2026 10:04:54 +0100
Subject: [PATCH] std.hash_map: fix `removeByPtr` with array key type

Resolves: https://codeberg.org/ziglang/zig/issues/32086
---
 lib/std/hash_map.zig | 21 ++++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/lib/std/hash_map.zig b/lib/std/hash_map.zig
index cb74cbc08b..1b43531845 100644
--- a/lib/std/hash_map.zig
+++ b/lib/std/hash_map.zig
@@ -1271,7 +1271,7 @@ pub fn HashMapUnmanaged(
             // map, which is assumed to exist as key_ptr must be valid.  This
             // item must be at index 0.
             const idx = if (@sizeOf(K) > 0)
-                (key_ptr - self.keys())
+                @as([*]K, @ptrCast(key_ptr)) - self.keys()
             else
                 0;
 
@@ -2175,3 +2175,22 @@ test "rehash" {
         }
     }
 }
+
+test "removeByPtr, key is array" {
+    const gpa = testing.allocator;
+
+    var map: AutoHashMapUnmanaged([2]u32, u32) = .empty;
+    defer map.deinit(gpa);
+
+    const key: [2]u32 = .{ 1, 2 };
+    try map.put(gpa, key, 3);
+
+    try expectEqual(1, map.count());
+    try expectEqual(3, map.get(key));
+
+    const key_ptr = map.getKeyPtr(key).?;
+    map.removeByPtr(key_ptr);
+
+    try expectEqual(0, map.count());
+    try expectEqual(null, map.get(key));
+}