From 4b1035f7ba94a1d247e4be3c4636f0b6fcab210c Mon Sep 17 00:00:00 2001
From: Mike <45243121+tankf33der@users.noreply.github.com>
Date: Mon, 20 Oct 2025 11:43:02 +0300
Subject: [PATCH] arrays: fix rotate_left() and rotate_right(), add test
 (#25539)

---
 vlib/arrays/arrays.v      |  2 +-
 vlib/arrays/arrays_test.v | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/vlib/arrays/arrays.v b/vlib/arrays/arrays.v
index b45c815e4..bea985957 100644
--- a/vlib/arrays/arrays.v
+++ b/vlib/arrays/arrays.v
@@ -633,7 +633,7 @@ fn memswap(x voidptr, y voidptr, len usize) {
 		unsafe {
 			vmemcpy(t, voidptr(xi), block_size)
 			vmemcpy(voidptr(xi), voidptr(yi), block_size)
-			vmemcpy(t, voidptr(yi), block_size)
+			vmemcpy(voidptr(yi), t, block_size)
 		}
 		i += usize(block_size)
 	}
diff --git a/vlib/arrays/arrays_test.v b/vlib/arrays/arrays_test.v
index 690e100e1..d0969901f 100644
--- a/vlib/arrays/arrays_test.v
+++ b/vlib/arrays/arrays_test.v
@@ -325,6 +325,24 @@ fn test_rotate_right() {
 	assert x == [5, 6, 1, 2, 3, 4]
 }
 
+fn test_rotate_right_long() {
+	mut x := []u64{len: 128, init: 255}
+	x[0] = 0
+	x[1] = 0
+	x[2] = 0
+	rotate_right(mut x, 64)
+	assert x.len == 128
+	idx := index_of_first(x, fn (idx int, x u64) bool {
+		return x == 0
+	})
+	assert idx == 64
+	assert x[idx - 1] == 255
+	assert x[idx] == 0
+	assert x[idx + 1] == 0
+	assert x[idx + 2] == 0
+	assert x[idx + 3] == 255
+}
+
 fn test_rotate_left() {
 	mut x := [1, 2, 3, 4, 5, 6]
 	rotate_left(mut x, 2)
-- 
2.39.5