diff --git a/client/deps/liblua/lbitlib.c b/client/deps/liblua/lbitlib.c
index 090e52b8b..f36ec0265 100644
--- a/client/deps/liblua/lbitlib.c
+++ b/client/deps/liblua/lbitlib.c
@@ -128,7 +128,9 @@ static int b_rot(lua_State *L, int i) {
     b_uint r = luaL_checkunsigned(L, 1);
     i &= (LUA_NBITS - 1);  /* i = i % NBITS */
     r = trim(r);
-    r = (r << i) | (r >> (LUA_NBITS - i));
+    if (i != 0)  /* avoid undefined shift of LUA_NBITS when i == 0 */
+        r = (r << i) | (r >> (LUA_NBITS - i));
+
     lua_pushunsigned(L, trim(r));
     return 1;
 }