diff --git a/lib/awful/button.lua b/lib/awful/button.lua
index 4fbe98d6a..cf3bf1c7d 100644
--- a/lib/awful/button.lua
+++ b/lib/awful/button.lua
@@ -258,14 +258,14 @@ local obj_mt = {
 -- @tparam function args.on_release Callback for when the button is released.
 -- @treturn table An `awful.button` object.
 
-local function new_common(mod, _button, press, release)
+local function new_common(mod, btn, press, release)
     local ret = {}
     local subsets = gmath.subsets(ignore_modifiers)
 
     for _, set in ipairs(subsets) do
         local sub_button = capi.button {
             modifiers = gtable.join(mod, set),
-            button    = _button
+            button    = btn
         }
 
         sub_button._private._legacy_convert_to = ret
@@ -294,9 +294,9 @@ local function new_common(mod, _button, press, release)
     return setmetatable(ret, obj_mt)
 end
 
-function button.new(args, _button, press, release)
+function button.new(args, btn, press, release)
     -- Assume this is the new constructor.
-    if not _button then
+    if not btn then
         assert(not (press or release), "Calling awful.button() requires a button name")
         return new_common(
             args.modifiers,
@@ -305,7 +305,7 @@ function button.new(args, _button, press, release)
             args.on_release
         )
     else
-        return new_common(args, _button, press, release)
+        return new_common(args, btn, press, release)
     end
 end
 
diff --git a/lib/awful/key.lua b/lib/awful/key.lua
index 8ff15d162..ec111ce52 100644
--- a/lib/awful/key.lua
+++ b/lib/awful/key.lua
@@ -271,7 +271,7 @@ end
 -- @treturn table A table with one or several key objects.
 -- @constructorfct awful.key
 
-local function new_common(mod, _keys, press, release, data)
+local function new_common(mod, keys, press, release, data)
     if type(release)=='table' then
         data=release
         release=nil
@@ -279,7 +279,7 @@ local function new_common(mod, _keys, press, release, data)
 
     local ret = {}
     local subsets = gmath.subsets(key.ignore_modifiers)
-    for _, key_pair in ipairs(_keys) do
+    for _, key_pair in ipairs(keys) do
         for _, set in ipairs(subsets) do
             local sub_key = capi.key {
                 modifiers = gtable.join(mod, set),
@@ -315,15 +315,15 @@ local function new_common(mod, _keys, press, release, data)
     -- append custom userdata (like description) to a hotkey
     data = data and gtable.clone(data) or {}
     data.mod = mod
-    data.keys = _keys
+    data.keys = keys
     data.on_press = press
     data.on_release = release
     data._is_capi_key = false
     assert((not data.key) or type(data.key) == "string")
     table.insert(key.hotkeys, data)
     data.execute = function(_)
-        assert(#_keys == 1, "key:execute() makes no sense for groups")
-        key.execute(mod, _keys[1])
+        assert(#keys == 1, "key:execute() makes no sense for groups")
+        key.execute(mod, keys[1])
     end
 
     -- Store the private data
@@ -412,9 +412,9 @@ local function get_keys(args)
     return key.keygroups[args.keygroup]
 end
 
-function key.new(args, _key, press, release, data)
+function key.new(args, keycode, press, release, data)
     -- Assume this is the new constructor.
-    if not _key then
+    if not keycode then
         assert(not (press or release or data), "Calling awful.key() requires a key name")
 
         local keys = get_keys(args)
@@ -427,7 +427,7 @@ function key.new(args, _key, press, release, data)
             args
         )
     else
-        return new_common(args, {{_key}}, press, release, data)
+        return new_common(args, {{keycode}}, press, release, data)
     end
 end
 
@@ -436,11 +436,11 @@ end
 -- @param pressed_mod The modifiers to compare with.
 -- @param pressed_key The key to compare with.
 -- @staticfct awful.key.match
-function key.match(_key, pressed_mod, pressed_key)
+function key.match(self, pressed_mod, pressed_key)
     -- First, compare key.
-    if pressed_key ~= _key.key then return false end
+    if pressed_key ~= self.key then return false end
     -- Then, compare mod
-    local mod = _key.modifiers
+    local mod = self.modifiers
     -- For each modifier of the key object, check that the modifier has been
     -- pressed.
     for _, m in ipairs(mod) do
diff --git a/lib/awful/keygrabber.lua b/lib/awful/keygrabber.lua
index df597e4c0..84599702a 100644
--- a/lib/awful/keygrabber.lua
+++ b/lib/awful/keygrabber.lua
@@ -480,7 +480,7 @@ end
 -- @method stop
 -- @emits stopped
 -- @emits property::current_instance
-function keygrabber:stop(_stop_key, _stop_mods) -- (at)function disables ldoc params
+function keygrabber:stop(_stop_key, _stop_mods) --luacheck: ignore 214
     keygrab.stop(self.grabber)
 
     local timer = self._private.timer
@@ -508,7 +508,7 @@ end
 -- @tparam awful.key key The key.
 -- @tparam string description.group The keybinding group
 
-function keygrabber:add_keybinding(key, _keycode, _callback, _description)
+function keygrabber:add_keybinding(key, _keycode, _callback, _description) --luacheck: ignore 214
     local mods = not key._is_awful_key and key or nil
 
     if mods then
diff --git a/lib/awful/layout/init.lua b/lib/awful/layout/init.lua
index d820fa8d4..fc8af8ec9 100644
--- a/lib/awful/layout/init.lua
+++ b/lib/awful/layout/init.lua
@@ -145,12 +145,12 @@ function layout.inc(i, s, layouts)
 end
 
 --- Set the layout function of the current tag.
--- @param _layout Layout name.
+-- @tparam layout|function l Layout object or function.
 -- @tparam[opt=mouse.screen.selected_tag] tag t The tag to modify.
 -- @staticfct awful.layout.set
-function layout.set(_layout, t)
+function layout.set(l, t)
     t = t or capi.mouse.screen.selected_tag
-    t.layout = _layout
+    t.layout = l
 end
 
 --- Get the layout parameters used for the screen
diff --git a/lib/awful/layout/suit/floating.lua b/lib/awful/layout/suit/floating.lua
index 9c2e6ea42..f3a9a9b7e 100644
--- a/lib/awful/layout/suit/floating.lua
+++ b/lib/awful/layout/suit/floating.lua
@@ -33,71 +33,80 @@ function floating.mouse_resize_handler(c, corner, x, y)
     local fixed_y = c.maximized_vertical
 
     local prev_coords = {}
-    local coordinates_delta = {x=0,y=0}
+    local coordinates_delta = {x=0, y=0}
+
     if floating.resize_jump_to_corner then
       -- Warp mouse pointer
       capi.mouse.coords({ x = x, y = y })
     else
       local corner_x, corner_y = x, y
       local mouse_coords = capi.mouse.coords()
+
       x = mouse_coords.x
       y = mouse_coords.y
-      coordinates_delta = {x=corner_x-x,y=corner_y-y}
+      coordinates_delta = {x = corner_x-x,y = corner_y-y}
     end
 
-    capi.mousegrabber.run(function (_mouse)
-                              if not c.valid then return false end
+    capi.mousegrabber.run(function (state)
+        if not c.valid then return false end
 
-                              _mouse.x = _mouse.x + coordinates_delta.x
-                              _mouse.y = _mouse.y + coordinates_delta.y
-                              for _, v in ipairs(_mouse.buttons) do
-                                  if v then
-                                      local ng
-                                      prev_coords = { x =_mouse.x, y = _mouse.y }
-                                      if corner == "bottom_right" then
-                                          ng = { width = _mouse.x - g.x,
-                                                 height = _mouse.y - g.y }
-                                      elseif corner == "bottom_left" then
-                                          ng = { x = _mouse.x,
-                                                 width = (g.x + g.width) - _mouse.x,
-                                                 height = _mouse.y - g.y }
-                                      elseif corner == "top_left" then
-                                          ng = { x = _mouse.x,
-                                                 width = (g.x + g.width) - _mouse.x,
-                                                 y = _mouse.y,
-                                                 height = (g.y + g.height) - _mouse.y }
-                                      else
-                                          ng = { width = _mouse.x - g.x,
-                                                 y = _mouse.y,
-                                                 height = (g.y + g.height) - _mouse.y }
-                                      end
-                                      if ng.width <= 0 then ng.width = nil end
-                                      if ng.height <= 0 then ng.height = nil end
-                                      if fixed_x then ng.width = g.width ng.x = g.x end
-                                      if fixed_y then ng.height = g.height ng.y = g.y end
-                                      c:geometry(ng)
-                                      -- Get real geometry that has been applied
-                                      -- in case we honor size hints
-                                      -- XXX: This should be rewritten when size
-                                      -- hints are available from Lua.
-                                      local rg = c:geometry()
+        state.x = state.x + coordinates_delta.x
+        state.y = state.y + coordinates_delta.y
 
-                                      if corner == "bottom_right" then
-                                          ng = {}
-                                      elseif corner == "bottom_left" then
-                                          ng = { x = (g.x + g.width) - rg.width  }
-                                      elseif corner == "top_left" then
-                                          ng = { x = (g.x + g.width) - rg.width,
-                                                 y = (g.y + g.height) - rg.height }
-                                      else
-                                          ng = { y = (g.y + g.height) - rg.height }
-                                      end
-                                      c:geometry({ x = ng.x, y = ng.y })
-                                      return true
-                                  end
-                              end
-                              return prev_coords.x == _mouse.x and prev_coords.y == _mouse.y
-                          end, corner .. "_corner")
+        for _, v in ipairs(state.buttons) do
+            if v then
+                local ng
+
+                prev_coords = { x = state.x, y = state.y }
+
+                if corner == "bottom_right" then
+                    ng = { width = state.x - g.x,
+                            height = state.y - g.y }
+                elseif corner == "bottom_left" then
+                    ng = { x = state.x,
+                            width = (g.x + g.width) - state.x,
+                            height = state.y - g.y }
+                elseif corner == "top_left" then
+                    ng = { x = state.x,
+                            width = (g.x + g.width) - state.x,
+                            y = state.y,
+                            height = (g.y + g.height) - state.y }
+                else
+                    ng = { width = state.x - g.x,
+                            y = state.y,
+                            height = (g.y + g.height) - state.y }
+                end
+
+                if ng.width <= 0 then ng.width = nil end
+                if ng.height <= 0 then ng.height = nil end
+                if fixed_x then ng.width = g.width ng.x = g.x end
+                if fixed_y then ng.height = g.height ng.y = g.y end
+
+                c:geometry(ng)
+                -- Get real geometry that has been applied
+                -- in case we honor size hints
+                -- XXX: This should be rewritten when size
+                -- hints are available from Lua.
+                local rg = c:geometry()
+
+                if corner == "bottom_right" then
+                    ng = {}
+                elseif corner == "bottom_left" then
+                    ng = { x = (g.x + g.width) - rg.width  }
+                elseif corner == "top_left" then
+                    ng = { x = (g.x + g.width) - rg.width,
+                            y = (g.y + g.height) - rg.height }
+                else
+                    ng = { y = (g.y + g.height) - rg.height }
+                end
+
+                c:geometry({ x = ng.x, y = ng.y })
+                return true
+            end
+        end
+
+        return prev_coords.x == state.x and prev_coords.y == state.y
+    end, corner .. "_corner")
 end
 
 function floating.arrange()
diff --git a/lib/awful/layout/suit/magnifier.lua b/lib/awful/layout/suit/magnifier.lua
index 9faffdcd7..c2c56883d 100644
--- a/lib/awful/layout/suit/magnifier.lua
+++ b/lib/awful/layout/suit/magnifier.lua
@@ -33,14 +33,14 @@ function magnifier.mouse_resize_handler(c, corner, x, y)
     local maxdist_pow = (wa.width^2 + wa.height^2) / 4
 
     local prev_coords = {}
-    capi.mousegrabber.run(function (_mouse)
+    capi.mousegrabber.run(function (position)
                               if not c.valid then return false end
 
-                              for _, v in ipairs(_mouse.buttons) do
+                              for _, v in ipairs(position.buttons) do
                                   if v then
-                                      prev_coords = { x =_mouse.x, y = _mouse.y }
-                                      local dx = center_x - _mouse.x
-                                      local dy = center_y - _mouse.y
+                                      prev_coords = { x =position.x, y = position.y }
+                                      local dx = center_x - position.x
+                                      local dy = center_y - position.y
                                       local dist = dx^2 + dy^2
 
                                       -- New master width factor
@@ -50,7 +50,7 @@ function magnifier.mouse_resize_handler(c, corner, x, y)
                                       return true
                                   end
                               end
-                              return prev_coords.x == _mouse.x and prev_coords.y == _mouse.y
+                              return prev_coords.x == position.x and prev_coords.y == position.y
                           end, corner .. "_corner")
 end
 
diff --git a/lib/awful/layout/suit/spiral.lua b/lib/awful/layout/suit/spiral.lua
index 0a7eb9b0b..629d9828a 100644
--- a/lib/awful/layout/suit/spiral.lua
+++ b/lib/awful/layout/suit/spiral.lua
@@ -24,7 +24,7 @@ local math = math
 
 local spiral = {}
 
-local function do_spiral(p, _spiral)
+local function do_spiral(p, is_spiral)
     local wa = p.workarea
     local cls = p.clients
     local n = #cls
@@ -43,19 +43,19 @@ local function do_spiral(p, _spiral)
             end
         end
 
-        if k % 4 == 0 and _spiral then
+        if k % 4 == 0 and is_spiral then
             wa.x = wa.x - wa.width
         elseif k % 2 == 0 then
             wa.x = wa.x + old_width
-        elseif k % 4 == 3 and k < n and _spiral then
+        elseif k % 4 == 3 and k < n and is_spiral then
             wa.x = wa.x + math.ceil(old_width / 2)
         end
 
-        if k % 4 == 1 and k ~= 1 and _spiral then
+        if k % 4 == 1 and k ~= 1 and is_spiral then
             wa.y = wa.y - wa.height
         elseif k % 2 == 1 and k ~= 1 then
             wa.y = wa.y + old_height
-        elseif k % 4 == 0 and k < n and _spiral then
+        elseif k % 4 == 0 and k < n and is_spiral then
             wa.y = wa.y + math.ceil(old_height / 2)
         end
 
diff --git a/lib/awful/layout/suit/tile.lua b/lib/awful/layout/suit/tile.lua
index 335398fb7..4609a0579 100644
--- a/lib/awful/layout/suit/tile.lua
+++ b/lib/awful/layout/suit/tile.lua
@@ -61,7 +61,7 @@ local function mouse_resize_handler(c, _, _, _, orientation)
         if g.height+15 > wa.height then
             offset = g.height * .5
             cursor = "sb_h_double_arrow"
-        elseif not (g.y+g.height+15 > wa.y+wa.height) then
+        elseif g.y+g.height+15 <= wa.y+wa.height then
             offset = g.height
         end
         corner_coords = { x = wa.x + wa.width * mwfact, y = g.y + offset }
@@ -70,7 +70,7 @@ local function mouse_resize_handler(c, _, _, _, orientation)
         if g.height+15 >= wa.height then
             offset = g.height * .5
             cursor = "sb_h_double_arrow"
-        elseif not (g.y+g.height+15 > wa.y+wa.height) then
+        elseif g.y+g.height+15 <= wa.y+wa.height then
             offset = g.height
         end
         corner_coords = { x = wa.x + wa.width * (1 - mwfact), y = g.y + offset }
@@ -79,7 +79,7 @@ local function mouse_resize_handler(c, _, _, _, orientation)
         if g.width+15 >= wa.width then
             offset = g.width * .5
             cursor = "sb_v_double_arrow"
-        elseif not (g.x+g.width+15 > wa.x+wa.width) then
+        elseif g.x+g.width+15 <= wa.x+wa.width then
             offset = g.width
         end
         corner_coords = { y = wa.y + wa.height * mwfact, x = g.x + offset}
@@ -88,7 +88,7 @@ local function mouse_resize_handler(c, _, _, _, orientation)
         if g.width+15 >= wa.width then
             offset = g.width * .5
             cursor = "sb_v_double_arrow"
-        elseif not (g.x+g.width+15 > wa.x+wa.width) then
+        elseif g.x+g.width+15 <= wa.x+wa.width then
             offset = g.width
         end
         corner_coords = { y = wa.y + wa.height * (1 - mwfact), x= g.x + offset }
@@ -104,16 +104,16 @@ local function mouse_resize_handler(c, _, _, _, orientation)
     end
 
     local prev_coords = {}
-    capi.mousegrabber.run(function (_mouse)
+    capi.mousegrabber.run(function (coords)
                               if not c.valid then return false end
 
-                              _mouse.x = _mouse.x + coordinates_delta.x
-                              _mouse.y = _mouse.y + coordinates_delta.y
-                              for _, v in ipairs(_mouse.buttons) do
+                              coords.x = coords.x + coordinates_delta.x
+                              coords.y = coords.y + coordinates_delta.y
+                              for _, v in ipairs(coords.buttons) do
                                   if v then
-                                      prev_coords = { x =_mouse.x, y = _mouse.y }
-                                      local fact_x = (_mouse.x - wa.x) / wa.width
-                                      local fact_y = (_mouse.y - wa.y) / wa.height
+                                      prev_coords = { x =coords.x, y = coords.y }
+                                      local fact_x = (coords.x - wa.x) / wa.width
+                                      local fact_y = (coords.y - wa.y) / wa.height
                                       local new_mwfact
 
                                       local geom = c:geometry()
@@ -123,15 +123,15 @@ local function mouse_resize_handler(c, _, _, _, orientation)
                                       local wfact
                                       local wfact_x, wfact_y
                                       if (geom.y+geom.height+15) > (wa.y+wa.height) then
-                                          wfact_y = (geom.y + geom.height - _mouse.y) / wa.height
+                                          wfact_y = (geom.y + geom.height - coords.y) / wa.height
                                       else
-                                          wfact_y = (_mouse.y - geom.y) / wa.height
+                                          wfact_y = (coords.y - geom.y) / wa.height
                                       end
 
                                       if (geom.x+geom.width+15) > (wa.x+wa.width) then
-                                          wfact_x = (geom.x + geom.width - _mouse.x) / wa.width
+                                          wfact_x = (geom.x + geom.width - coords.x) / wa.width
                                       else
-                                          wfact_x = (_mouse.x - geom.x) / wa.width
+                                          wfact_x = (coords.x - geom.x) / wa.width
                                       end
 
 
@@ -155,7 +155,7 @@ local function mouse_resize_handler(c, _, _, _, orientation)
                                       return true
                                   end
                               end
-                              return prev_coords.x == _mouse.x and prev_coords.y == _mouse.y
+                              return prev_coords.x == coords.x and prev_coords.y == coords.y
                           end, cursor)
 end
 
diff --git a/lib/awful/menu.lua b/lib/awful/menu.lua
index 9b4667f0b..4e87ee232 100644
--- a/lib/awful/menu.lua
+++ b/lib/awful/menu.lua
@@ -147,16 +147,16 @@ local function load_theme(a, b)
 end
 
 
-local function item_position(_menu, child)
+local function item_position(self, child)
     local a, b = "height", "width"
-    local dir = _menu.layout.dir or "y"
+    local dir = self.layout.dir or "y"
     if dir == "x" then  a, b = b, a  end
 
-    local in_dir, other = 0, _menu[b]
-    local num = gtable.hasitem(_menu.child, child)
+    local in_dir, other = 0, self[b]
+    local num = gtable.hasitem(self.child, child)
     if num then
         for i = 0, num - 1 do
-            local item = _menu.items[i]
+            local item = self.items[i]
             if item then
                 other = math.max(other, item[b])
                 in_dir = in_dir + item[a]
@@ -169,97 +169,97 @@ local function item_position(_menu, child)
 end
 
 
-local function set_coords(_menu, s, m_coords)
+local function set_coords(self, s, m_coords)
     local s_geometry = s.workarea
     local screen_w = s_geometry.x + s_geometry.width
     local screen_h = s_geometry.y + s_geometry.height
 
-    _menu.width = _menu.wibox.width
-    _menu.height = _menu.wibox.height
+    self.width = self.wibox.width
+    self.height = self.wibox.height
 
-    _menu.x = _menu.wibox.x
-    _menu.y = _menu.wibox.y
+    self.x = self.wibox.x
+    self.y = self.wibox.y
 
-    if _menu.parent then
-        local w, h = item_position(_menu.parent, _menu)
-        w = w + _menu.parent.theme.border_width
+    if self.parent then
+        local w, h = item_position(self.parent, self)
+        w = w + self.parent.theme.border_width
 
-        _menu.y = _menu.parent.y + h + _menu.height > screen_h and
-                 screen_h - _menu.height or _menu.parent.y + h
-        _menu.x = _menu.parent.x + w + _menu.width > screen_w and
-                 _menu.parent.x - _menu.width or _menu.parent.x + w
+        self.y = self.parent.y + h + self.height > screen_h and
+                 screen_h - self.height or self.parent.y + h
+        self.x = self.parent.x + w + self.width > screen_w and
+                 self.parent.x - self.width or self.parent.x + w
     else
         if m_coords == nil then
             m_coords = capi.mouse.coords()
             m_coords.x = m_coords.x + 1
             m_coords.y = m_coords.y + 1
         end
-        _menu.y = m_coords.y < s_geometry.y and s_geometry.y or m_coords.y
-        _menu.x = m_coords.x < s_geometry.x and s_geometry.x or m_coords.x
+        self.y = m_coords.y < s_geometry.y and s_geometry.y or m_coords.y
+        self.x = m_coords.x < s_geometry.x and s_geometry.x or m_coords.x
 
-        _menu.y = _menu.y + _menu.height > screen_h and
-                 screen_h - _menu.height or _menu.y
-        _menu.x = _menu.x + _menu.width  > screen_w and
-                 screen_w - _menu.width  or _menu.x
+        self.y = self.y + self.height > screen_h and
+                 screen_h - self.height or self.y
+        self.x = self.x + self.width  > screen_w and
+                 screen_w - self.width  or self.x
     end
 
-    _menu.wibox.x = _menu.x
-    _menu.wibox.y = _menu.y
+    self.wibox.x = self.x
+    self.wibox.y = self.y
 end
 
 
-local function set_size(_menu)
+local function set_size(self)
     local in_dir, other, a, b = 0, 0, "height", "width"
-    local dir = _menu.layout.dir or "y"
+    local dir = self.layout.dir or "y"
     if dir == "x" then  a, b = b, a  end
-    for _, item in ipairs(_menu.items) do
+    for _, item in ipairs(self.items) do
         other = math.max(other, item[b])
         in_dir = in_dir + item[a]
     end
-    _menu[a], _menu[b] = in_dir, other
+    self[a], self[b] = in_dir, other
     if in_dir > 0 and other > 0 then
-        _menu.wibox[a] = in_dir
-        _menu.wibox[b] = other
+        self.wibox[a] = in_dir
+        self.wibox[b] = other
         return true
     end
     return false
 end
 
 
-local function check_access_key(_menu, key)
-   for i, item in ipairs(_menu.items) do
+local function check_access_key(self, key)
+   for i, item in ipairs(self.items) do
       if item.akey == key then
-            _menu:item_enter(i)
-            _menu:exec(i, { exec = true })
+            self:item_enter(i)
+            self:exec(i, { exec = true })
             return
       end
    end
-   if _menu.parent then
-      check_access_key(_menu.parent, key)
+   if self.parent then
+      check_access_key(self.parent, key)
    end
 end
 
 
-local function grabber(_menu, _, key, event)
+local function grabber(self, _, key, event)
     if event ~= "press" then return end
 
-    local sel = _menu.sel or 0
+    local sel = self.sel or 0
     if gtable.hasitem(menu.menu_keys.up, key) then
-        local sel_new = sel-1 < 1 and #_menu.items or sel-1
-        _menu:item_enter(sel_new)
+        local sel_new = sel-1 < 1 and #self.items or sel-1
+        self:item_enter(sel_new)
     elseif gtable.hasitem(menu.menu_keys.down, key) then
-        local sel_new = sel+1 > #_menu.items and 1 or sel+1
-        _menu:item_enter(sel_new)
+        local sel_new = sel+1 > #self.items and 1 or sel+1
+        self:item_enter(sel_new)
     elseif sel > 0 and gtable.hasitem(menu.menu_keys.enter, key) then
-        _menu:exec(sel)
+        self:exec(sel)
     elseif sel > 0 and gtable.hasitem(menu.menu_keys.exec, key) then
-        _menu:exec(sel, { exec = true })
+        self:exec(sel, { exec = true })
     elseif gtable.hasitem(menu.menu_keys.back, key) then
-        _menu:hide()
+        self:hide()
     elseif gtable.hasitem(menu.menu_keys.close, key) then
-        menu.get_root(_menu):hide()
+        menu.get_root(self):hide()
     else
-        check_access_key(_menu, key)
+        check_access_key(self, key)
     end
 end
 
diff --git a/lib/awful/mouse/resize.lua b/lib/awful/mouse/resize.lua
index ceb883506..7d6b7e349 100644
--- a/lib/awful/mouse/resize.lua
+++ b/lib/awful/mouse/resize.lua
@@ -154,7 +154,7 @@ local function handler(_, client, context, args) --luacheck: no unused_args
         or "fleur"
 
     -- Execute the placement function and use request::geometry
-    capi.mousegrabber.run(function (_mouse)
+    capi.mousegrabber.run(function (coords)
         if not client.valid then return end
 
         -- Resize everytime the mouse moves (default behavior) in live mode,
@@ -194,7 +194,7 @@ local function handler(_, client, context, args) --luacheck: no unused_args
         end
 
         -- Quit when the button is released
-        for _,v in pairs(_mouse.buttons) do
+        for _,v in pairs(coords.buttons) do
             if v then return true end
         end
 
diff --git a/lib/awful/placement.lua b/lib/awful/placement.lua
index 3a6c4b605..7802bcf8b 100644
--- a/lib/awful/placement.lua
+++ b/lib/awful/placement.lua
@@ -858,8 +858,8 @@ function placement.closest_corner(d, args)
     local corner_i, corner_j, n
 
     -- Use the product of 3 to get the closest point in a NxN matrix
-    local function f(_n, mat)
-        n        = _n
+    local function f(dim, mat)
+        n        = dim
         -- The +1 is required to avoid a rounding error when
         --    pos.x == sgeo.x+sgeo.width
         corner_i = -math.ceil( ( (sgeo.x - pos.x) * n) / (sgeo.width  + 1))
diff --git a/lib/awful/screen.lua b/lib/awful/screen.lua
index 8e444e521..a73675828 100644
--- a/lib/awful/screen.lua
+++ b/lib/awful/screen.lua
@@ -155,10 +155,10 @@ end
 -- This moves the mouse pointer to the last known position on the new screen,
 -- or keeps its position relative to the current focused screen.
 -- @staticfct awful.screen.focus_bydirection
--- @param dir The direction, can be either "up", "down", "left" or "right".
--- @param _screen Screen.
-function screen.focus_bydirection(dir, _screen)
-    local sel = get_screen(_screen or screen.focused())
+-- @tparam string dir The direction, can be either "up", "down", "left" or "right".
+-- @tparam screen s Screen.
+function screen.focus_bydirection(dir, s)
+    local sel = get_screen(s or screen.focused())
     local target = sel:get_next_in_direction(dir)
 
     if target then
@@ -228,18 +228,18 @@ end
 --- Get or set the screen padding.
 --
 -- @deprecated awful.screen.padding
--- @param _screen The screen object to change the padding on
+-- @param s The screen object to change the padding on
 -- @param[opt=nil] padding The padding, a table with 'top', 'left', 'right' and/or
 -- 'bottom' or a number value to apply set the same padding on all sides. Can be
 --  nil if you only want to retrieve padding
 -- @treturn table A table with left, right, top and bottom number values.
 -- @see padding
-function screen.padding(_screen, padding)
+function screen.padding(s, padding)
     gdebug.deprecate("Use _screen.padding = value instead of awful.screen.padding", {deprecated_in=4})
     if padding then
-        screen.object.set_padding(_screen, padding)
+        screen.object.set_padding(s, padding)
     end
-    return screen.object.get_padding(_screen)
+    return screen.object.get_padding(s)
 end
 
 --- The screen padding.
diff --git a/lib/awful/tag.lua b/lib/awful/tag.lua
index fcd8f1b4f..7bd7a008b 100644
--- a/lib/awful/tag.lua
+++ b/lib/awful/tag.lua
@@ -1650,10 +1650,10 @@ end
 -- Do not use.
 --
 -- @deprecated awful.tag.getdata
--- @tparam tag _tag The tag.
+-- @tparam tag t The tag.
 -- @return The data table.
-function tag.getdata(_tag)
-    return _tag._private.awful_tag_properties
+function tag.getdata(t)
+    return t._private.awful_tag_properties
 end
 
 --- Get a tag property.
@@ -1661,14 +1661,14 @@ end
 -- Use `_tag.prop` directly.
 --
 -- @deprecated awful.tag.getproperty
--- @tparam tag _tag The tag.
+-- @tparam tag t The tag.
 -- @tparam string prop The property name.
 -- @return The property.
-function tag.getproperty(_tag, prop)
-    if not _tag then return end -- FIXME: Turn this into an error?
+function tag.getproperty(t, prop)
+    if not t then return end -- FIXME: Turn this into an error?
 
-    if _tag._private.awful_tag_properties then
-       return _tag._private.awful_tag_properties[prop]
+    if t._private.awful_tag_properties then
+       return t._private.awful_tag_properties[prop]
     end
 end
 
@@ -1676,20 +1676,20 @@ end
 -- This properties are internal to awful. Some are used to draw taglist, or to
 -- handle layout, etc.
 --
--- Use `_tag.prop = value`
+-- Use `t.prop = value`
 --
 -- @deprecated awful.tag.setproperty
--- @param _tag The tag.
+-- @param t The tag.
 -- @param prop The property name.
 -- @param value The value.
-function tag.setproperty(_tag, prop, value)
-    if not _tag._private.awful_tag_properties then
-        _tag._private.awful_tag_properties = {}
+function tag.setproperty(t, prop, value)
+    if not t._private.awful_tag_properties then
+        t._private.awful_tag_properties = {}
     end
 
-    if _tag._private.awful_tag_properties[prop] ~= value then
-        _tag._private.awful_tag_properties[prop] = value
-        _tag:emit_signal("property::" .. prop)
+    if t._private.awful_tag_properties[prop] ~= value then
+        t._private.awful_tag_properties[prop] = value
+        t:emit_signal("property::" .. prop)
     end
 end
 
@@ -1721,9 +1721,9 @@ end
 
 local function attached_connect_signal_screen(screen, sig, func)
     screen = get_screen(screen)
-    capi.tag.connect_signal(sig, function(_tag)
-        if get_screen(tag.getproperty(_tag, "screen")) == screen then
-            func(_tag)
+    capi.tag.connect_signal(sig, function(t)
+        if get_screen(tag.getproperty(t, "screen")) == screen then
+            func(t)
         end
     end)
 end
diff --git a/lib/gears/geometry.lua b/lib/gears/geometry.lua
index d9a203039..a65360b8b 100644
--- a/lib/gears/geometry.lua
+++ b/lib/gears/geometry.lua
@@ -117,23 +117,23 @@ end
 -- * right
 --
 -- @tparam string dir The direction.
--- @tparam table _gA The first rectangle.
--- @tparam table _gB The second rectangle.
+-- @tparam table gA The first rectangle.
+-- @tparam table gB The second rectangle.
 -- @return The distance between the screens.
-local function calculate_distance(dir, _gA, _gB)
-    local gAx = _gA.x
-    local gAy = _gA.y
-    local gBx = _gB.x
-    local gBy = _gB.y
+local function calculate_distance(dir, gA, gB)
+    local gAx = gA.x
+    local gAy = gA.y
+    local gBx = gB.x
+    local gBy = gB.y
 
     if dir == "up" then
-        gBy = _gB.y + _gB.height
+        gBy = gB.y + gB.height
     elseif dir == "down" then
-        gAy = _gA.y + _gA.height
+        gAy = gA.y + gA.height
     elseif dir == "left" then
-        gBx = _gB.x + _gB.width
+        gBx = gB.x + gB.width
     elseif dir == "right" then
-        gAx = _gA.x + _gA.width
+        gAx = gA.x + gA.width
     end
 
     return math.sqrt((gBx - gAx) ^ 2 + (gBy - gAy) ^ 2)
diff --git a/lib/gears/matcher.lua b/lib/gears/matcher.lua
index d024a2134..869147c9d 100644
--- a/lib/gears/matcher.lua
+++ b/lib/gears/matcher.lua
@@ -358,8 +358,8 @@ end
 -- @treturn boolean Returns false if a dependency conflict was found.
 -- @method add_matching_rules
 function matcher:add_matching_rules(name, rules, depends_on, precede)
-    local function matching_fct(_self, c, props, callbacks)
-        default_rules_callback(_self, c, props, callbacks, rules)
+    local function matching_fct(_, c, props, callbacks)
+        default_rules_callback(self, c, props, callbacks, rules)
     end
 
     self._matching_rules[name] = rules
diff --git a/lib/gears/surface.lua b/lib/gears/surface.lua
index b85c7de19..55d22116b 100644
--- a/lib/gears/surface.lua
+++ b/lib/gears/surface.lua
@@ -31,7 +31,7 @@ end
 
 --- Try to convert the argument into an lgi cairo surface.
 -- This is usually needed for loading images by file name.
--- @param _surface The surface to load or nil
+-- @param surface The surface to load or nil
 -- @param default The default value to return on error; when nil, then a surface
 -- in an error state is returned.
 -- @return The loaded surface, or the replacement default
@@ -67,60 +67,60 @@ end
 --- Try to convert the argument into an lgi cairo surface.
 -- This is usually needed for loading images by file name and uses a cache.
 -- In contrast to `load()`, errors are returned to the caller.
--- @param _surface The surface to load or nil
+-- @param surface The surface to load or nil
 -- @param default The default value to return on error; when nil, then a surface
 -- in an error state is returned.
 -- @return The loaded surface, or the replacement default, or nil if called with
 -- nil.
 -- @return An error message, or nil on success.
 -- @staticfct load_silently
-function surface.load_silently(_surface, default)
-    if type(_surface) == "string" then
-        local cache = surface_cache[_surface]
+function surface.load_silently(self, default)
+    if type(self) == "string" then
+        local cache = surface_cache[self]
         if cache then
             return cache
         end
-        local result, err = surface.load_uncached_silently(_surface, default)
+        local result, err = surface.load_uncached_silently(self, default)
         if not err then
             -- Cache the file
-            surface_cache[_surface] = result
+            surface_cache[self] = result
         end
         return result, err
     end
-    return surface.load_uncached_silently(_surface, default)
+    return surface.load_uncached_silently(self, default)
 end
 
-local function do_load_and_handle_errors(_surface, func)
-    if type(_surface) == 'nil' then
+local function do_load_and_handle_errors(self, func)
+    if type(self) == 'nil' then
         return get_default()
     end
-    local result, err = func(_surface, false)
+    local result, err = func(self, false)
     if result then
         return result
     end
     gdebug.print_error(debug.traceback(
-        "Failed to load '" .. tostring(_surface) .. "': " .. tostring(err)))
+        "Failed to load '" .. tostring(self) .. "': " .. tostring(err)))
     return get_default()
 end
 
 --- Try to convert the argument into an lgi cairo surface.
 -- This is usually needed for loading images by file name. Errors are handled
 -- via `gears.debug.print_error`.
--- @param _surface The surface to load or nil
+-- @param surface The surface to load or nil
 -- @return The loaded surface, or nil
 -- @staticfct load_uncached
-function surface.load_uncached(_surface)
-    return do_load_and_handle_errors(_surface, surface.load_uncached_silently)
+function surface.load_uncached(self)
+    return do_load_and_handle_errors(self, surface.load_uncached_silently)
 end
 
 --- Try to convert the argument into an lgi cairo surface.
 -- This is usually needed for loading images by file name. Errors are handled
 -- via `gears.debug.print_error`.
--- @param _surface The surface to load or nil
+-- @param surface The surface to load or nil
 -- @return The loaded surface, or nil.
 -- @staticfct gears.surface
-function surface.load(_surface)
-    return do_load_and_handle_errors(_surface, surface.load_silently)
+function surface.load(self)
+    return do_load_and_handle_errors(self, surface.load_silently)
 end
 
 function surface.mt.__call(_, ...)
diff --git a/lib/ruled/client.lua b/lib/ruled/client.lua
index bd4f318a1..54af13a3d 100644
--- a/lib/ruled/client.lua
+++ b/lib/ruled/client.lua
@@ -152,22 +152,22 @@ end
 
 --- Get list of matching rules for a client.
 -- @tparam client c The client.
--- @tparam table _rules The rules to check. List with "rule", "rule_any", "except" and
+-- @tparam table rules The rules to check. List with "rule", "rule_any", "except" and
 --   "except_any" keys.
 -- @treturn table The list of matched rules.
 -- @staticfct ruled.client.matching_rules
-function module.matching_rules(c, _rules)
-    return crules:matching_rules(c, _rules)
+function module.matchingrules(c, rules)
+    return crules:matching_rules(c, rules)
 end
 
 --- Check if a client matches a given set of rules.
 -- @tparam client c The client.
--- @tparam table _rules The rules to check. List of tables with `rule`, `rule_any`,
+-- @tparam table rules The rules to check. List of tables with `rule`, `rule_any`,
 --   `except` and `except_any` keys.
 -- @treturn bool True if at least one rule is matched, false otherwise.
 -- @staticfct ruled.client.matches_list
-function module.matches_list(c, _rules)
-    return crules:matches_rules(c, _rules)
+function module.matches_list(c, rules)
+    return crules:matchesrules(c, rules)
 end
 
 --- Remove a source.
diff --git a/lib/wibox/drawable.lua b/lib/wibox/drawable.lua
index f24832f3c..b8748df77 100644
--- a/lib/wibox/drawable.lua
+++ b/lib/wibox/drawable.lua
@@ -21,7 +21,7 @@ local surface = require("gears.surface")
 local timer = require("gears.timer")
 local grect =  require("gears.geometry").rectangle
 local matrix = require("gears.matrix")
-local hierarchy = require("wibox.hierarchy")
+local whierarchy = require("wibox.hierarchy")
 local unpack = unpack or table.unpack -- luacheck: globals unpack (compatibility with Lua 5.1)
 
 local visible_drawables = {}
@@ -92,7 +92,7 @@ local function do_redraw(self)
             self._need_complete_repaint = true
             if self._widget then
                 self._widget_hierarchy_callback_arg = {}
-                self._widget_hierarchy = hierarchy.new(context, self._widget, width, height,
+                self._widget_hierarchy = whierarchy.new(context, self._widget, width, height,
                         self._redraw_callback, self._layout_callback, self._widget_hierarchy_callback_arg)
             else
                 self._widget_hierarchy = nil
@@ -166,12 +166,12 @@ local function do_redraw(self)
     assert(cr.status == "SUCCESS", "Cairo context entered error state: " .. cr.status)
 end
 
-local function find_widgets(_drawable, result, _hierarchy, x, y)
-    local m = _hierarchy:get_matrix_from_device()
+local function find_widgets(self, result, hierarchy, x, y)
+    local m = hierarchy:get_matrix_from_device()
 
     -- Is (x,y) inside of this hierarchy or any child (aka the draw extents)
     local x1, y1 = m:transform_point(x, y)
-    local x2, y2, w2, h2 = _hierarchy:get_draw_extents()
+    local x2, y2, w2, h2 = hierarchy:get_draw_extents()
     if x1 < x2 or x1 >= x2 + w2 then
         return
     end
@@ -180,22 +180,22 @@ local function find_widgets(_drawable, result, _hierarchy, x, y)
     end
 
     -- Is (x,y) inside of this widget?
-    local width, height = _hierarchy:get_size()
+    local width, height = hierarchy:get_size()
     if x1 >= 0 and y1 >= 0 and x1 <= width and y1 <= height then
         -- Get the extents of this widget in the device space
-        local x3, y3, w3, h3 = matrix.transform_rectangle(_hierarchy:get_matrix_to_device(),
+        local x3, y3, w3, h3 = matrix.transform_rectangle(hierarchy:get_matrix_to_device(),
             0, 0, width, height)
         table.insert(result, {
             x = x3, y = y3, width = w3, height = h3,
             widget_width = width,
             widget_height = height,
-            drawable = _drawable,
-            widget = _hierarchy:get_widget(),
-            hierarchy = _hierarchy
+            drawable = self,
+            widget = hierarchy:get_widget(),
+            hierarchy = hierarchy
         })
     end
-    for _, child in ipairs(_hierarchy:get_children()) do
-        find_widgets(_drawable, result, child, x, y)
+    for _, child in ipairs(hierarchy:get_children()) do
+        find_widgets(self, result, child, x, y)
     end
 end
 
@@ -221,7 +221,7 @@ end
 
 -- Private API. Not documented on purpose.
 function drawable._set_systray_widget(widget)
-    hierarchy.count_widget(widget)
+    whierarchy.count_widget(widget)
     systray_widget = widget
 end
 
@@ -331,34 +331,36 @@ local function emit_difference(name, list, skip)
     end
 end
 
-local function handle_leave(_drawable)
-    emit_difference("mouse::leave", _drawable._widgets_under_mouse, {})
-    _drawable._widgets_under_mouse = {}
+local function handle_leave(self)
+    emit_difference("mouse::leave", self._widgets_under_mouse, {})
+    self._widgets_under_mouse = {}
 end
 
-local function handle_motion(_drawable, x, y)
-    if x < 0 or y < 0 or x > _drawable.drawable:geometry().width or y > _drawable.drawable:geometry().height then
-        return handle_leave(_drawable)
+local function handle_motion(self, x, y)
+    local dgeo = self.drawable:geometry()
+
+    if x < 0 or y < 0 or x > dgeo.width or y > dgeo.height then
+        return handle_leave(self)
     end
 
     -- Build a plain list of all widgets on that point
-    local widgets_list = _drawable:find_widgets(x, y)
+    local widgets_list = self:find_widgets(x, y)
 
     -- First, "leave" all widgets that were left
-    emit_difference("mouse::leave", _drawable._widgets_under_mouse, widgets_list)
+    emit_difference("mouse::leave", self._widgets_under_mouse, widgets_list)
     -- Then enter some widgets
-    emit_difference("mouse::enter", widgets_list, _drawable._widgets_under_mouse)
+    emit_difference("mouse::enter", widgets_list, self._widgets_under_mouse)
 
-    _drawable._widgets_under_mouse = widgets_list
+    self._widgets_under_mouse = widgets_list
 end
 
-local function setup_signals(_drawable)
-    local d = _drawable.drawable
+local function setup_signals(self)
+    local d = self.drawable
 
     local function clone_signal(name)
         -- When "name" is emitted on wibox.drawin, also emit it on wibox
         d:connect_signal(name, function(_, ...)
-            _drawable:emit_signal(name, ...)
+            self:emit_signal(name, ...)
         end)
     end
     clone_signal("button::press")
diff --git a/lib/wibox/init.lua b/lib/wibox/init.lua
index ccbfe36a9..e606864b7 100644
--- a/lib/wibox/init.lua
+++ b/lib/wibox/init.lua
@@ -246,16 +246,16 @@ object.properties._legacy_accessors(wibox.object, "buttons", "_buttons", true, f
     ) or false
 end, true)
 
-local function setup_signals(_wibox)
+local function setup_signals(w)
     local obj
     local function clone_signal(name)
         -- When "name" is emitted on wibox.drawin, also emit it on wibox
         obj:connect_signal(name, function(_, ...)
-            _wibox:emit_signal(name, ...)
+            w:emit_signal(name, ...)
         end)
     end
 
-    obj = _wibox.drawin
+    obj = w.drawin
     clone_signal("property::border_color")
     clone_signal("property::border_width")
     clone_signal("property::buttons")
@@ -273,7 +273,7 @@ local function setup_signals(_wibox)
     clone_signal("property::shape_clip")
     clone_signal("property::shape_input")
 
-    obj = _wibox._drawable
+    obj = w._drawable
     clone_signal("button::press")
     clone_signal("button::release")
     clone_signal("mouse::enter")
diff --git a/lib/wibox/widget/graph.lua b/lib/wibox/widget/graph.lua
index ac0eba8a4..51b5d7545 100644
--- a/lib/wibox/widget/graph.lua
+++ b/lib/wibox/widget/graph.lua
@@ -343,9 +343,21 @@ prop_fallbacks.nan_color = build_fallback_nan_color()
 --
 
 local function graph_gather_drawn_values_num_stats(self, new_value)
-    if not (new_value >= 0) then
-        return -- is negative or NaN
-    end
+    -- Because the graphs are at risk of dividing by zero, the value can
+    -- be `inf`, `-inf` and `-nan`. For example:
+    --
+    -- nan = 0/0
+    -- print(not (nan >= 0), nan < 0)
+    -- > true, false
+    --
+    -- Because if this, we need to ignore the luacheck rule which promotes
+    -- the removal of double negative and DeMorgan's law style optimizations.
+    -- Those only works on real numbers, which `NaN` and `Inf` are not part of.
+    --
+    -- The `luacheck` project decided that adding this check by default and
+    -- adding annotations where it doesn't work is the way to go
+    -- https://github.com/lunarmodules/luacheck/issues/43#issuecomment-1014949507
+    if not (new_value >= 0) then return end --luacheck: ignore 581
 
     local last_value = self._private.last_drawn_values_num or 0
     -- Grow instantly and shrink slow