diff --git a/docs/common/object.ldoc b/docs/common/object.ldoc
index 19dfbd03b..24285299d 100644
--- a/docs/common/object.ldoc
+++ b/docs/common/object.ldoc
@@ -2,7 +2,6 @@
 --- Disonnect to a signal.
 -- @tparam string name The name of the signal
 -- @tparam function func The callback that should be disconnected
--- @see add_signal
 -- @function disconnect_signal
 
 --- Emit a signal.
@@ -13,15 +12,9 @@
 --   that are given to emit_signal()
 -- @function emit_signal
 
---- Add a signal to an object. All signals must be added before they can be used.
---
--- @tparam string name The name of the new signal.
--- @function add_signal
-
 --- Connect to a signal.
 -- @tparam string name The name of the signal
 -- @tparam function func The callback to call when the signal is emitted
--- @see add_signal 
 -- @function connect_signal
 
 --- Connect to a signal weakly. This allows the callback function to be garbage
diff --git a/lib/awful/client.lua b/lib/awful/client.lua
index e4fed3cd4..fcf17a4e8 100644
--- a/lib/awful/client.lua
+++ b/lib/awful/client.lua
@@ -1159,25 +1159,17 @@ end
 
 --- The last geometry when client was floating.
 -- @signal property::floating_geometry
-capi.client.add_signal("property::floating_geometry")
-
-capi.client.add_signal("property::floating")
-
-capi.client.add_signal("property::dockable")
 
 --- Emited when a client need to get a titlebar.
 -- @signal request::titlebars
 -- @tparam[opt=nil] string content The context (like "rules")
 -- @tparam[opt=nil] table hints Some hints.
-capi.client.add_signal("request::titlebars")
 
 --- The client marked signal (deprecated).
 -- @signal .marked
-capi.client.add_signal("marked")
 
 --- The client unmarked signal (deprecated).
 -- @signal unmarked
-capi.client.add_signal("unmarked")
 
 -- Add clients during startup to focus history.
 -- This used to happen through ewmh.activate, but that only handles visible
diff --git a/lib/awful/layout/init.lua b/lib/awful/layout/init.lua
index 114b12b3e..085702573 100644
--- a/lib/awful/layout/init.lua
+++ b/lib/awful/layout/init.lua
@@ -222,8 +222,6 @@ local function arrange_tag(t)
     layout.arrange(t.screen)
 end
 
-capi.screen.add_signal("arrange")
-
 capi.tag.connect_signal("property::master_width_factor", arrange_tag)
 capi.tag.connect_signal("property::master_count", arrange_tag)
 capi.tag.connect_signal("property::column_count", arrange_tag)
diff --git a/lib/awful/placement.lua b/lib/awful/placement.lua
index 5d2c59ae4..c003d3f1f 100644
--- a/lib/awful/placement.lua
+++ b/lib/awful/placement.lua
@@ -558,7 +558,6 @@ attach = function(d, position_f, args)
     end
 
     -- Create a way to detach a placement function
-    d:add_signal("property::detach_callback")
     function d.detach_callback()
         d:disconnect_signal("property::width"       , tracker)
         d:disconnect_signal("property::height"      , tracker)
diff --git a/lib/awful/screen.lua b/lib/awful/screen.lua
index cc384f91a..9073dd9f7 100644
--- a/lib/awful/screen.lua
+++ b/lib/awful/screen.lua
@@ -465,8 +465,6 @@ function screen.object.set_selected_tag() end
 --- When the tag history changed.
 -- @signal tag::history::update
 
-capi.screen.add_signal("padding")
-
 -- Extend the luaobject
 object.properties(capi.screen, {
     getter_class = screen.object,
diff --git a/lib/awful/spawn.lua b/lib/awful/spawn.lua
index e34998155..c9d203cb0 100644
--- a/lib/awful/spawn.lua
+++ b/lib/awful/spawn.lua
@@ -297,7 +297,5 @@ capi.awesome.connect_signal("spawn::canceled" , spawn.on_snid_cancel   )
 capi.awesome.connect_signal("spawn::timeout"  , spawn.on_snid_cancel   )
 capi.client.connect_signal ("manage"          , spawn.on_snid_callback )
 
-capi.client.add_signal    ("spawn::completed_with_payload"            )
-
 return setmetatable(spawn, { __call = function(_, ...) return spawn.spawn(...) end })
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80
diff --git a/lib/awful/tag.lua b/lib/awful/tag.lua
index 94edb3300..8ff168bd9 100644
--- a/lib/awful/tag.lua
+++ b/lib/awful/tag.lua
@@ -1323,22 +1323,6 @@ capi.client.connect_signal("untagged", client_untagged)
 capi.client.connect_signal("tagged", client_tagged)
 capi.tag.connect_signal("request::select", tag.object.view_only)
 
-capi.tag.add_signal("property::hide")
-capi.tag.add_signal("property::icon")
-capi.tag.add_signal("property::icon_only")
-capi.tag.add_signal("property::layout")
-capi.tag.add_signal("property::mwfact")
-capi.tag.add_signal("property::master_width_factor")
-capi.tag.add_signal("property::useless_gap")
-capi.tag.add_signal("property::master_fill_policy")
-capi.tag.add_signal("property::ncol")
-capi.tag.add_signal("property::column_count")
-capi.tag.add_signal("property::nmaster")
-capi.tag.add_signal("property::master_count")
-capi.tag.add_signal("property::windowfact")
-capi.tag.add_signal("property::screen")
-capi.tag.add_signal("property::index")
-
 --- True when a tagged client is urgent
 -- @signal property::urgent
 -- @see client.urgent
@@ -1347,15 +1331,6 @@ capi.tag.add_signal("property::index")
 -- @signal property::urgent_count
 -- @see client.urgent
 
-capi.tag.add_signal("property::urgent")
-
-capi.tag.add_signal("property::urgent_count")
-capi.tag.add_signal("property::volatile")
-capi.tag.add_signal("request::screen")
-capi.tag.add_signal("removal-pending")
-
-capi.screen.add_signal("tag::history::update")
-
 capi.screen.connect_signal("tag::history::update", tag.history.update)
 
 capi.screen.connect_signal("removed", function(s)
diff --git a/lib/awful/tooltip.lua b/lib/awful/tooltip.lua
index 2e1ba4df9..3a2fec5e2 100644
--- a/lib/awful/tooltip.lua
+++ b/lib/awful/tooltip.lua
@@ -196,7 +196,6 @@ end
 -- @see set_markup
 tooltip.new = function(args)
     local self = setmetatable(object(), instance_mt)
-    self:add_signal("property::visible")
     self.visible = false
 
     -- private data
diff --git a/lib/awful/wibar.lua b/lib/awful/wibar.lua
index af0950308..9c52a261b 100644
--- a/lib/awful/wibar.lua
+++ b/lib/awful/wibar.lua
@@ -341,11 +341,9 @@ function awfulwibar.new(arg)
     w._screen  = screen --HACK When a screen is removed, then getbycoords wont work
     w._stretch = arg.stretch == nil and has_to_stretch or arg.stretch
 
-    w:add_signal("property::position")
     w.get_position = get_position
     w.set_position = set_position
 
-    w:add_signal("property::stretch")
     w.get_stretch = get_stretch
     w.set_stretch = set_stretch
     w.remove      = remove
diff --git a/lib/gears/object.lua b/lib/gears/object.lua
index c65582ed8..25e4ae63c 100644
--- a/lib/gears/object.lua
+++ b/lib/gears/object.lua
@@ -21,45 +21,36 @@ local object = { properties = properties, mt = {} }
 --- Verify that obj is indeed a valid object as returned by new()
 local function check(obj)
     if type(obj) ~= "table" or type(obj._signals) ~= "table" then
-        error("add_signal() called on non-object")
+        error("called on non-object")
     end
 end
 
 --- Find a given signal
 -- @tparam table obj The object to search in
 -- @tparam string name The signal to find
--- @tparam string error_msg Error message for if the signal is not found
 -- @treturn table The signal table
-local function find_signal(obj, name, error_msg)
+local function find_signal(obj, name)
     check(obj)
     if not obj._signals[name] then
-        error("Trying to " .. error_msg .. " non-existent signal '" .. name .. "'")
-    end
-    return obj._signals[name]
-end
-
---- Add a signal to an object. All signals must be added before they can be used.
---
---@DOC_text_gears_object_signal_EXAMPLE@
--- @tparam string name The name of the new signal.
-function object:add_signal(name)
-    check(self)
-    assert(type(name) == "string", "name must be a string, got: " .. type(name))
-    if not self._signals[name] then
-        self._signals[name] = {
+        assert(type(name) == "string", "name must be a string, got: " .. type(name))
+        obj._signals[name] = {
             strong = {},
             weak = setmetatable({}, { __mode = "kv" })
         }
     end
+    return obj._signals[name]
+end
+
+function object.add_signal()
+    require("awful.util").deprecate("Use signals without explicitly adding them. This is now done implicitly.")
 end
 
 --- Connect to a signal.
 -- @tparam string name The name of the signal
 -- @tparam function func The callback to call when the signal is emitted
--- @see add_signal 
 function object:connect_signal(name, func)
     assert(type(func) == "function", "callback must be a function, got: " .. type(func))
-    local sig = find_signal(self, name, "connect to")
+    local sig = find_signal(self, name)
     assert(sig.weak[func] == nil, "Trying to connect a strong callback which is already connected weakly")
     sig.strong[func] = true
 end
@@ -100,7 +91,7 @@ end
 -- @tparam function func The callback to call when the signal is emitted
 function object:weak_connect_signal(name, func)
     assert(type(func) == "function", "callback must be a function, got: " .. type(func))
-    local sig = find_signal(self, name, "connect to")
+    local sig = find_signal(self, name)
     assert(sig.strong[func] == nil, "Trying to connect a weak callback which is already connected strongly")
     sig.weak[func] = make_the_gc_obey(func)
 end
@@ -108,9 +99,8 @@ end
 --- Disonnect to a signal.
 -- @tparam string name The name of the signal
 -- @tparam function func The callback that should be disconnected
--- @see add_signal
 function object:disconnect_signal(name, func)
-    local sig = find_signal(self, name, "disconnect from")
+    local sig = find_signal(self, name)
     sig.weak[func] = nil
     sig.strong[func] = nil
 end
@@ -122,7 +112,7 @@ end
 --   function receives the object as first argument and then any extra arguments
 --   that are given to emit_signal()
 function object:emit_signal(name, ...)
-    local sig = find_signal(self, name, "emit")
+    local sig = find_signal(self, name)
     for func in pairs(sig.strong) do
         func(self, ...)
     end
@@ -163,8 +153,8 @@ local function set_miss(self, key, value)
     end
 end
 
---- Returns a new object. You can call `:emit_signal()`, `:disconnect_signal()`,
--- `:connect_signal()` and `:add_signal()` on the resulting object.
+--- Returns a new object. You can call `:emit_signal()`, `:disconnect_signal()`
+--  and `:connect_signal()` on the resulting object.
 --
 -- Note that `args.enable_auto_signals` is only supported when
 -- `args.enable_properties` is true.
diff --git a/lib/gears/timer.lua b/lib/gears/timer.lua
index 7c320ef2f..fbd69bcf5 100644
--- a/lib/gears/timer.lua
+++ b/lib/gears/timer.lua
@@ -97,11 +97,6 @@ local timer_instance_mt = {
 timer.new = function(args)
     local ret = object()
 
-    ret:add_signal("property::timeout")
-    ret:add_signal("timeout")
-    ret:add_signal("start")
-    ret:add_signal("stop")
-
     ret.data = { timeout = 0 }
     setmetatable(ret, timer_instance_mt)
 
diff --git a/lib/wibox/drawable.lua b/lib/wibox/drawable.lua
index 1f2c038e3..75cce527d 100644
--- a/lib/wibox/drawable.lua
+++ b/lib/wibox/drawable.lua
@@ -298,7 +298,6 @@ local function setup_signals(_drawable)
     local d = _drawable.drawable
 
     local function clone_signal(name)
-        _drawable:add_signal(name)
         -- When "name" is emitted on wibox.drawin, also emit it on wibox
         d:connect_signal(name, function(_, ...)
             _drawable:emit_signal(name, ...)
diff --git a/lib/wibox/init.lua b/lib/wibox/init.lua
index e4f4fdf1f..23de6ee2d 100644
--- a/lib/wibox/init.lua
+++ b/lib/wibox/init.lua
@@ -89,7 +89,6 @@ end
 local function setup_signals(_wibox)
     local obj
     local function clone_signal(name)
-        _wibox:add_signal(name)
         -- When "name" is emitted on wibox.drawin, also emit it on wibox
         obj:connect_signal(name, function(_, ...)
             _wibox:emit_signal(name, ...)
@@ -225,8 +224,6 @@ local function new(args)
     return ret
 end
 
-capi.drawin.add_signal("property::get_wibox")
-
 --- Redraw a wibox. You should never have to call this explicitely because it is
 -- automatically called when needed.
 -- @param wibox
diff --git a/lib/wibox/widget/base.lua b/lib/wibox/widget/base.lua
index 54a04cb9d..e498875b7 100644
--- a/lib/wibox/widget/base.lua
+++ b/lib/wibox/widget/base.lua
@@ -556,18 +556,8 @@ function base.make_widget(proxy, widget_name, args)
         class             = args.class,
     }
 
-    -- This signal is used by layouts to find out when they have to update.
-    ret:add_signal("widget::layout_changed")
-    ret:add_signal("widget::redraw_needed")
-    -- Mouse input, oh noes!
-    ret:add_signal("button::press")
-    ret:add_signal("button::release")
-    ret:add_signal("mouse::enter")
-    ret:add_signal("mouse::leave")
-
     -- Backwards compatibility
     -- TODO: Remove this
-    ret:add_signal("widget::updated")
     ret:connect_signal("widget::updated", function()
         ret:emit_signal("widget::layout_changed")
         ret:emit_signal("widget::redraw_needed")
@@ -648,7 +638,7 @@ end
 function base.check_widget(widget)
     assert(type(widget) == "table", "Type should be table, but is " .. tostring(type(widget)))
     assert(widget.is_widget, "Argument is not a widget!")
-    for _, func in pairs({ "add_signal", "connect_signal", "disconnect_signal" }) do
+    for _, func in pairs({ "connect_signal", "disconnect_signal" }) do
         assert(type(widget[func]) == "function", func .. " is not a function")
     end
 end
diff --git a/spec/awful/screen_spec.lua b/spec/awful/screen_spec.lua
index 6c36daad6..7a9a31ee2 100644
--- a/spec/awful/screen_spec.lua
+++ b/spec/awful/screen_spec.lua
@@ -6,7 +6,6 @@
 local fake_screens = {}
 
 _G.screen = setmetatable({
-    add_signal = function() end,
     set_index_miss_handler = function() end,
     set_newindex_miss_handler = function() end,
 }, {
diff --git a/spec/gears/object_spec.lua b/spec/gears/object_spec.lua
index e73bc43ed..4bb0b7d84 100644
--- a/spec/gears/object_spec.lua
+++ b/spec/gears/object_spec.lua
@@ -9,31 +9,6 @@ describe("gears.object", function()
     local obj
     before_each(function()
         obj = object()
-        obj:add_signal("signal")
-    end)
-
-    it("strong connect non-existent signal", function()
-        assert.has.errors(function()
-            obj:connect_signal("foo", function() end)
-        end)
-    end)
-
-    it("weak connect non-existent signal", function()
-        assert.has.errors(function()
-            obj:weak_connect_signal("foo", function() end)
-        end)
-    end)
-
-    it("strong disconnect non-existent signal", function()
-        assert.has.errors(function()
-            obj:disconnect_signal("foo", function() end)
-        end)
-    end)
-
-    it("emitting non-existent signal", function()
-        assert.has.errors(function()
-            obj:emit_signal("foo")
-        end)
     end)
 
     it("strong connecting and emitting signal", function()
@@ -188,7 +163,6 @@ describe("gears.object", function()
 
     it("auto emit disabled", function()
         local got_it = false
-        obj:add_signal("property::foo")
         obj:connect_signal("property::foo", function() got_it=true end)
 
         obj.foo = 42
@@ -199,7 +173,6 @@ describe("gears.object", function()
     it("auto emit enabled", function()
         local got_it = false
         local obj2 = object{enable_auto_signals=true, enable_properties=true}
-        obj2:add_signal("property::foo")
         obj2:connect_signal("property::foo", function() got_it=true end)
 
         obj2.foo = 42
@@ -207,13 +180,6 @@ describe("gears.object", function()
         assert.is_true(got_it)
     end)
 
-    it("auto emit enabled", function()
-        assert.has.errors(function()
-            local obj2 = object{enable_auto_signals=true, enable_properties=true}
-            obj2.foo = "bar"
-        end)
-    end)
-
     it("auto emit without dynamic properties", function()
         assert.has.errors(function()
             object{enable_auto_signals=true, enable_properties=false}
diff --git a/spec/wibox/test_utils.lua b/spec/wibox/test_utils.lua
index dd895e747..756f2dc13 100644
--- a/spec/wibox/test_utils.lua
+++ b/spec/wibox/test_utils.lua
@@ -83,8 +83,6 @@ return {
     widget_stub = function(width, height)
         local w = object()
         w._private = {}
-        w:add_signal("widget::redraw_needed")
-        w:add_signal("widget::layout_changed")
         w.is_widget = true
         w._private.visible = true
         w._private.opacity = 1
diff --git a/tests/examples/shims/awesome.lua b/tests/examples/shims/awesome.lua
index 41c458a9f..7dd586c5b 100644
--- a/tests/examples/shims/awesome.lua
+++ b/tests/examples/shims/awesome.lua
@@ -17,12 +17,6 @@ local function _shim_fake_class()
         return obj._connect_signal(obj, name, func)
     end
 
-    obj._add_signal = obj.add_signal
-
-    function obj.add_signal(name)
-        return obj._add_signal(obj, name)
-    end
-
     function obj.set_index_miss_handler(handler)
         meta.__index = handler
     end
@@ -50,11 +44,6 @@ awesome.startup = true
 function awesome.register_xproperty()
 end
 
-awesome.add_signal("refresh")
-awesome.add_signal("wallpaper_changed")
-awesome.add_signal("spawn::canceled")
-awesome.add_signal("spawn::timeout")
-
 return awesome
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80
diff --git a/tests/examples/shims/client.lua b/tests/examples/shims/client.lua
index 5fcc64866..9b735e3d6 100644
--- a/tests/examples/shims/client.lua
+++ b/tests/examples/shims/client.lua
@@ -4,20 +4,6 @@ local clients = {}
 
 local client, meta = awesome._shim_fake_class()
 
-local function add_signals(c)
-    c:add_signal("property::width")
-    c:add_signal("property::height")
-    c:add_signal("property::x")
-    c:add_signal("property::y")
-    c:add_signal("property::screen")
-    c:add_signal("property::geometry")
-    c:add_signal("request::geometry")
-    c:add_signal("request::tag")
-    c:add_signal("swapped")
-    c:add_signal("raised")
-    c:add_signal("property::_label") --Used internally
-end
-
 -- Keep an history of the geometry for validation and images
 local function push_geometry(c)
     table.insert(c._old_geo, c:geometry())
@@ -46,9 +32,6 @@ function client.gen_fake(args)
         ret[v] = ret[v] or 1
     end
 
-
-    add_signals(ret)
-
     -- Emulate capi.client.geometry
     function ret:geometry(new)
         if new then
@@ -142,37 +125,6 @@ function client.get(s)
     return ret
 end
 
-client:_add_signal("manage")
-client:_add_signal("unmanage")
-client:_add_signal("property::urgent")
-client:_add_signal("untagged")
-client:_add_signal("tagged")
-client:_add_signal("property::shape_client_bounding")
-client:_add_signal("property::shape_client_clip")
-client:_add_signal("property::width")
-client:_add_signal("property::height")
-client:_add_signal("property::x")
-client:_add_signal("property::y")
-client:_add_signal("property::geometry")
-client:_add_signal("focus")
-client:_add_signal("new")
-client:_add_signal("property::size_hints_honor")
-client:_add_signal("property::struts")
-client:_add_signal("property::minimized")
-client:_add_signal("property::maximized_horizontal")
-client:_add_signal("property::maximized_vertical")
-client:_add_signal("property::sticky")
-client:_add_signal("property::fullscreen")
-client:_add_signal("property::border_width")
-client:_add_signal("property::hidden")
-client:_add_signal("property::screen")
-client:_add_signal("request::tag")
-client:_add_signal("request::geometry")
-client:_add_signal("request::activate")
-client:_add_signal("raised")
-client:_add_signal("lowered")
-client:_add_signal("list")
-
 return client
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80
diff --git a/tests/examples/shims/screen.lua b/tests/examples/shims/screen.lua
index ca36a0639..98de3e7ae 100644
--- a/tests/examples/shims/screen.lua
+++ b/tests/examples/shims/screen.lua
@@ -7,10 +7,6 @@ screen.count = 1
 local function create_screen(args)
     local s = gears_obj()
 
-    s:add_signal("property::workarea")
-    s:add_signal("property::index")
-    s:add_signal("padding")
-
     -- Copy the geo in case the args are mutated
     local geo = {
         x      = args.x     ,
@@ -99,10 +95,6 @@ end
 
 screen._add_screen {width=320, height=240}
 
-screen.add_signal("property::workarea")
-screen.add_signal("added")
-screen.add_signal("removed")
-
 return screen
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80
diff --git a/tests/examples/shims/tag.lua b/tests/examples/shims/tag.lua
index e8fd463e4..ff2ab4a7f 100644
--- a/tests/examples/shims/tag.lua
+++ b/tests/examples/shims/tag.lua
@@ -5,20 +5,6 @@ local tag, meta = awesome._shim_fake_class()
 local function new_tag(_, args)
     local ret = gears_obj()
 
-    ret:add_signal("property::layout")
-    ret:add_signal("property::name")
-    ret:add_signal("property::geometry")
-    ret:add_signal("property::screen")
-    ret:add_signal("property::master_width_factor")
-    ret:add_signal("property::mwfact")
-    ret:add_signal("property::ncol")
-    ret:add_signal("property::column_count")
-    ret:add_signal("property::master_count")
-    ret:add_signal("property::nmaster")
-    ret:add_signal("property::index")
-    ret:add_signal("property::useless_gap")
-    ret:add_signal("property::_wa_tracker")
-
     ret.name = args.name or "test"
     ret.activated = true
     ret.selected = true
@@ -42,12 +28,6 @@ local function new_tag(_, args)
     })
 end
 
-tag:_add_signal("request::select")
-tag:_add_signal("property::selected")
-tag:_add_signal("property::activated")
-tag:_add_signal("tagged")
-tag:_add_signal("untagged")
-
 return setmetatable(tag, {
     __call      = new_tag,
 })
diff --git a/tests/examples/text/gears/object/properties.lua b/tests/examples/text/gears/object/properties.lua
index 032ff9cce..5d69e1162 100644
--- a/tests/examples/text/gears/object/properties.lua
+++ b/tests/examples/text/gears/object/properties.lua
@@ -31,8 +31,6 @@ local o = gears.object {
     enable_auto_signals = true,
 }
 
-o:add_signal "property::foo"
-
 print(o.foo)
  
 o.foo = 42
@@ -42,7 +40,6 @@ print(o.foo)
 o:method(1, 2, 3)
 
  -- Random properties can also be added, the signal will be emited automatically.
-o:add_signal "property::something"
 
 o:connect_signal("property::something", function(obj, value)
     print("In the connection handler!", obj, value)
diff --git a/tests/examples/text/gears/object/signal.lua b/tests/examples/text/gears/object/signal.lua
index 50f9c1986..090aa2143 100644
--- a/tests/examples/text/gears/object/signal.lua
+++ b/tests/examples/text/gears/object/signal.lua
@@ -2,9 +2,6 @@ local gears = require("gears") --DOC_HIDE
 
 local o = gears.object{}
  
- -- Add a new signals to the object. This is used to catch typos
-o:add_signal "my_signal"
- 
  -- Function can be attached to signals
 local function slot(obj, a, b, c)
     print("In slot", obj, a, b, c)
diff --git a/tests/test-awful-client.lua b/tests/test-awful-client.lua
index ea72f031f..ca36318ca 100644
--- a/tests/test-awful-client.lua
+++ b/tests/test-awful-client.lua
@@ -18,7 +18,6 @@ client.focus = client.get()[1]
 local c  = client.focus
 -- local c2 = client.get()[2]
 
-client.add_signal("property::foo")
 c.foo = "bar"
 
 -- Check if the property system works