diff --git a/lib/awful/util.lua.in b/lib/awful/util.lua.in
index 8e0463630..e70ef62d6 100644
--- a/lib/awful/util.lua.in
+++ b/lib/awful/util.lua.in
@@ -237,9 +237,9 @@ end
 -- @return A new table containing all keys from the arguments.
 function table.join(...)
     local ret = {}
-    for i = 1, arg.n do
-        if arg[i] then
-            for k, v in pairs(arg[i]) do
+    for i, t in ipairs({...}) do
+        if t then
+            for k, v in pairs(t) do
                 if type(k) == "number" then
                     rtable.insert(ret, v)
                 else