diff --git a/.travis.yml b/.travis.yml
index 80edefa1..f973840b 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -79,7 +79,7 @@ install:
 
 script:
   - export CMAKE_ARGS="-DLUA_LIBRARY=${LUALIBRARY} -DLUA_INCLUDE_DIR=${LUAINCLUDE} -D OVERRIDE_VERSION=$AWESOME_VERSION"
-  - make && sudo env PATH=$PATH make install && awesome --version && tests/run.sh
+  - make && sudo env PATH=$PATH make install && awesome --version && make check
 
 after_success:
   # Push updated API docs for relevant branches, e.g. non-PRs builds on master.
diff --git a/awesomerc.lua b/awesomerc.lua
index 23311888..1344e171 100755
--- a/awesomerc.lua
+++ b/awesomerc.lua
@@ -297,7 +297,7 @@ globalkeys = awful.util.table.join(
 
     awful.key({ modkey, "Control" }, "n",
               function ()
-                  c = awful.client.restore()
+                  local c = awful.client.restore()
                   -- Focus restored client
                   if c then
                       client.focus = c
diff --git a/lib/awful/autofocus.lua b/lib/awful/autofocus.lua
index 8e7c02ca..0112cfc2 100644
--- a/lib/awful/autofocus.lua
+++ b/lib/awful/autofocus.lua
@@ -11,7 +11,6 @@
 ---------------------------------------------------------------------------
 
 local client = client
-local screen = screen
 local aclient = require("awful.client")
 local atag = require("awful.tag")
 local timer = require("gears.timer")
diff --git a/lib/awful/button.lua b/lib/awful/button.lua
index 47db912d..88e593d6 100644
--- a/lib/awful/button.lua
+++ b/lib/awful/button.lua
@@ -44,10 +44,10 @@ function button.new(mod, _button, press, release)
         ret[#ret + 1] = capi.button({ modifiers = util.table.join(mod, set),
                                       button = _button })
         if press then
-            ret[#ret]:connect_signal("press", function(bobj, ...) press(...) end)
+            ret[#ret]:connect_signal("press", function(_, ...) press(...) end)
         end
         if release then
-            ret[#ret]:connect_signal("release", function (bobj, ...) release(...) end)
+            ret[#ret]:connect_signal("release", function (_, ...) release(...) end)
         end
     end
     return ret
diff --git a/lib/awful/client.lua b/lib/awful/client.lua
index 2d2585a4..77d51bee 100644
--- a/lib/awful/client.lua
+++ b/lib/awful/client.lua
@@ -29,7 +29,7 @@ local capi =
 local screen
 do
     screen = setmetatable({}, {
-        __index = function(t, k)
+        __index = function(_, k)
             screen = require("awful.screen")
             return screen[k]
         end,
@@ -91,7 +91,7 @@ function client.urgent.get()
     else
         -- fallback behaviour: iterate through clients and get the first urgent
         local clients = capi.client.get()
-        for k, cl in pairs(clients) do
+        for _, cl in pairs(clients) do
             if cl.urgent then
                 return cl
             end
@@ -171,21 +171,21 @@ end
 
 --- Get the latest focused client for a screen in history.
 --
--- @tparam int screen The screen number to look for.
+-- @tparam int s The screen number to look for.
 -- @tparam int idx The index: 0 will return first candidate,
 --   1 will return second, etc.
 -- @tparam function filter An optional filter.  If no client is found in the
 --   first iteration, client.focus.filter is used by default to get any
 --   client.
 -- @treturn client.object A client.
-function client.focus.history.get(screen, idx, filter)
+function client.focus.history.get(s, idx, filter)
     -- When this counter is equal to idx, we return the client
     local counter = 0
-    local vc = client.visible(screen, true)
-    for k, c in ipairs(client.data.focus) do
-        if c.screen == screen then
+    local vc = client.visible(s, true)
+    for _, c in ipairs(client.data.focus) do
+        if c.screen == s then
             if not filter or filter(c) then
-                for j, vcc in ipairs(vc) do
+                for _, vcc in ipairs(vc) do
                     if vcc == c then
                         if counter == idx then
                             return c
@@ -200,9 +200,9 @@ function client.focus.history.get(screen, idx, filter)
     end
     -- Argh nobody found in history, give the first one visible if there is one
     -- that passes the filter.
-    local filter = filter or client.focus.filter
+    filter = filter or client.focus.filter
     if counter == 0 then
-        for k, v in ipairs(vc) do
+        for _, v in ipairs(vc) do
             if filter(v) then
                 return v
             end
@@ -223,13 +223,13 @@ end
 
 --- Get visible clients from a screen.
 --
--- @tparam[opt] integer screen The screen number, or nil for all screens.
+-- @tparam[opt] integer s The screen number, or nil for all screens.
 -- @tparam[opt=false] boolean stacked Use stacking order? (top to bottom)
 -- @treturn table A table with all visible clients.
-function client.visible(screen, stacked)
-    local cls = capi.client.get(screen, stacked)
+function client.visible(s, stacked)
+    local cls = capi.client.get(s, stacked)
     local vcls = {}
-    for k, c in pairs(cls) do
+    for _, c in pairs(cls) do
         if c:isvisible() then
             table.insert(vcls, c)
         end
@@ -239,14 +239,14 @@ end
 
 --- Get visible and tiled clients
 --
--- @tparam integer screen The screen number, or nil for all screens.
+-- @tparam integer s The screen number, or nil for all screens.
 -- @tparam[opt=false] boolean stacked Use stacking order? (top to bottom)
 -- @treturn table A table with all visible and tiled clients.
-function client.tiled(screen, stacked)
-    local clients = client.visible(screen, stacked)
+function client.tiled(s, stacked)
+    local clients = client.visible(s, stacked)
     local tclients = {}
     -- Remove floating clients
-    for k, c in pairs(clients) do
+    for _, c in pairs(clients) do
         if not client.floating.get(c)
             and not c.fullscreen
             and not c.maximized_vertical
@@ -261,7 +261,7 @@ end
 -- If no client is passed, the focused client will be used.
 --
 -- @tparam int i The index.  Use 1 to get the next, -1 to get the previous.
--- @client[opt] c The client.
+-- @client[opt] sel The client.
 -- @tparam[opt=false] boolean stacked Use stacking order? (top to bottom)
 -- @return A client, or nil if no client is available.
 --
@@ -269,15 +269,15 @@ end
 -- awful.client.next(1)
 -- -- focus the previous
 -- awful.client.next(-1)
-function client.next(i, c, stacked)
+function client.next(i, sel, stacked)
     -- Get currently focused client
-    local sel = c or capi.client.focus
+    sel = sel or capi.client.focus
     if sel then
         -- Get all visible clients
         local cls = client.visible(sel.screen, stacked)
         local fcls = {}
         -- Remove all non-normal clients
-        for idx, c in ipairs(cls) do
+        for _, c in ipairs(cls) do
             if client.focus.filter(c) or c == sel then
                 table.insert(fcls, c)
             end
@@ -385,9 +385,9 @@ end
 
 --- Swap a client with another client in the given direction. Swaps across screens.
 -- @param dir The direction, can be either "up", "down", "left" or "right".
--- @client[opt] c The client.
-function client.swap.global_bydirection(dir, c)
-    local sel = c or capi.client.focus
+-- @client[opt] sel The client.
+function client.swap.global_bydirection(dir, sel)
+    sel = sel or capi.client.focus
     local scr = sel and sel.screen or screen.focused()
 
     if sel then
@@ -463,7 +463,7 @@ end
 -- @client c The window to set as master.
 function client.setmaster(c)
     local cls = util.table.reverse(capi.client.get(c.screen))
-    for k, v in pairs(cls) do
+    for _, v in pairs(cls) do
         c:swap(v)
     end
 end
@@ -472,7 +472,7 @@ end
 -- @client c The window to set as slave.
 function client.setslave(c)
     local cls = capi.client.get(c.screen)
-    for k, v in pairs(cls) do
+    for _, v in pairs(cls) do
         c:swap(v)
     end
 end
@@ -565,7 +565,7 @@ end
 function client.mark(c)
     local cl = c or capi.client.focus
     if cl then
-        for k, v in pairs(client.data.marked) do
+        for _, v in pairs(client.data.marked) do
             if cl == v then
                 return false
             end
@@ -601,7 +601,7 @@ end
 function client.ismarked(c)
     local cl = c or capi.client.focus
     if cl then
-        for k, v in pairs(client.data.marked) do
+        for _, v in pairs(client.data.marked) do
             if cl == v then
                 return true
             end
@@ -613,8 +613,7 @@ end
 --- Toggle a client as marked.
 -- @client c The client to toggle mark.
 function client.togglemarked(c)
-    local cl = c or capi.client.focus
-
+    c = c or capi.client.focus
     if not client.mark(c) then
         client.unmark(c)
     end
@@ -623,11 +622,11 @@ end
 --- Return the marked clients and empty the marked table.
 -- @return A table with all marked clients.
 function client.getmarked()
-    for k, v in pairs(client.data.marked) do
+    for _, v in pairs(client.data.marked) do
         v:emit_signal("unmarked")
     end
 
-    t = client.data.marked
+    local t = client.data.marked
     client.data.marked = {}
     return t
 end
@@ -637,7 +636,7 @@ end
 -- @client c A client.
 -- @param s True or false.
 function client.floating.set(c, s)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     if c and client.property.get(c, "floating") ~= s then
         client.property.set(c, "floating", s)
         local scr = c.screen
@@ -655,12 +654,12 @@ local function store_floating_geometry(c)
 end
 
 -- Store the initial client geometry.
-capi.client.connect_signal("new", function(c)
+capi.client.connect_signal("new", function(cl)
     local function store_init_geometry(c)
         client.property.set(c, "floating_geometry", c:geometry())
         c:disconnect_signal("property::border_width", store_init_geometry)
     end
-    c:connect_signal("property::border_width", store_init_geometry)
+    cl:connect_signal("property::border_width", store_init_geometry)
 end)
 
 capi.client.connect_signal("property::geometry", store_floating_geometry)
@@ -668,7 +667,7 @@ capi.client.connect_signal("property::geometry", store_floating_geometry)
 --- Return if a client has a fixe size or not.
 -- @client c The client.
 function client.isfixed(c)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     if not c then return end
     local h = c.size_hints
     if h.min_width and h.max_width
@@ -688,7 +687,7 @@ end
 -- did not set them manually. For example, windows with a type different than
 -- normal.
 function client.floating.get(c)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     if c then
         local value = client.property.get(c, "floating")
         if value ~= nil then
@@ -708,7 +707,7 @@ end
 --- Toggle the floating state of a client between 'auto' and 'true'.
 -- @client c A client.
 function client.floating.toggle(c)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     -- If it has been set to floating
     if client.floating.get(c) then
         client.floating.set(c, false)
@@ -730,11 +729,10 @@ function client.restore(s)
     s = s or screen.focused()
     local cls = capi.client.get(s)
     local tags = tag.selectedlist(s)
-    local mcls = {}
-    for k, c in pairs(cls) do
+    for _, c in pairs(cls) do
         local ctags = c:tags()
         if c.minimized then
-            for k, t in ipairs(tags) do
+            for _, t in ipairs(tags) do
                 if util.table.hasitem(ctags, t) then
                     c.minimized = false
                     return c
@@ -749,7 +747,7 @@ end
 -- @param set the set of numbers to normalize
 -- @param num the number of numbers to normalize
 local function normalize(set, num)
-    local num = num or #set
+    num = num or #set
     local total = 0
     if num then
         for i = 1,num do
@@ -759,7 +757,7 @@ local function normalize(set, num)
             set[i] = set[i] / total
         end
     else
-        for i,v in ipairs(set) do
+        for _,v in ipairs(set) do
             total = total + v
         end
 
@@ -777,7 +775,7 @@ end
 -- @return idx index of the client in the column
 -- @return num the number of visible clients in the column
 function client.idx(c)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     if not c then return end
 
     -- Only check the tiled clients, the others un irrelevant
@@ -836,7 +834,7 @@ end
 -- @client c the client
 function client.setwfact(wfact, c)
     -- get the currently selected window
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     if not c or not c:isvisible() then return end
 
     local w = client.idx(c)
@@ -845,9 +843,6 @@ function client.setwfact(wfact, c)
 
     local t = tag.selected(c.screen)
 
-    local cls = client.tiled(tag.getscreen(t))
-    local nmaster = tag.getnmaster(t)
-
     -- n is the number of windows currently visible for which we have to be concerned with the properties
     local data = tag.getproperty(t, "windowfact") or {}
     local colfact = data[w.col]
@@ -890,17 +885,16 @@ end
 -- @param add amount to increase the client's window
 -- @client c the client
 function client.incwfact(add, c)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     if not c then return end
 
     local t = tag.selected(c.screen)
 
     local w = client.idx(c)
 
-    local nmaster = tag.getnmaster(t)
     local data = tag.getproperty(t, "windowfact") or {}
     local colfact = data[w.col] or {}
-    curr = colfact[w.idx] or 1
+    local curr = colfact[w.idx] or 1
     colfact[w.idx] = curr + add
 
     -- keep our ratios normalized
@@ -982,15 +976,15 @@ end
 --- Set a client property to be persistent across restarts (via X properties).
 --
 -- @param prop The property name.
--- @param type The type (used for register_xproperty).
+-- @param kind The type (used for register_xproperty).
 --   One of "string", "number" or "boolean".
-function client.property.persist(prop, type)
+function client.property.persist(prop, kind)
     local xprop = "awful.client.property." .. prop
-    capi.awesome.register_xproperty(xprop, type)
+    capi.awesome.register_xproperty(xprop, kind)
     client.data.persistent_properties_registered[prop] = true
 
     -- Make already-set properties persistent
-    for c, tab in pairs(client.data.properties) do
+    for c in pairs(client.data.properties) do
         if client.data.properties[c] and client.data.properties[c][prop] ~= nil then
             c:set_xproperty(xprop, client.data.properties[c][prop])
         end
@@ -1017,7 +1011,7 @@ end
 function client.iterate(filter, start, s)
     local clients = capi.client.get(s)
     local focused = capi.client.focus
-    local start   = start or util.table.hasitem(clients, focused)
+    start         = start or util.table.hasitem(clients, focused)
     return util.table.iterate(clients, filter, start)
 end
 
@@ -1041,13 +1035,13 @@ function client.run_or_raise(cmd, matcher, merge)
     local findex  = util.table.hasitem(clients, capi.client.focus) or 1
     local start   = util.cycle(#clients, findex + 1)
 
-    for c in client.iterate(matcher, start) do
+    local c = client.iterate(matcher, start)()
+    if c then
         client.jumpto(c, merge)
-        return
+    else
+        -- client not found, spawn it
+        spawn(cmd)
     end
-
-    -- client not found, spawn it
-    spawn(cmd)
 end
 
 --- Get a matching transient_for client (if any).
diff --git a/lib/awful/client/shape.lua b/lib/awful/client/shape.lua
index 2f0fe1da..e1280e0e 100644
--- a/lib/awful/client/shape.lua
+++ b/lib/awful/client/shape.lua
@@ -20,11 +20,11 @@ shape.update = {}
 
 --- Get one of a client's shapes and transform it to include window decorations
 -- @client c The client whose shape should be retrieved
--- @tparam string shape Either "bounding" or "clip"
-function shape.get_transformed(c, shape)
-    local border = shape == "bounding" and c.border_width or 0
-    local shape = surface.load_silently(c["client_shape_" .. shape], false)
-    if not shape then return end
+-- @tparam string shape_name Either "bounding" or "clip"
+function shape.get_transformed(c, shape_name)
+    local border = shape_name == "bounding" and c.border_width or 0
+    local shape_img = surface.load_silently(c["client_shape_" .. shape_name], false)
+    if not shape_img then return end
 
     -- Get information about various sizes on the client
     local geom = c:geometry()
@@ -44,7 +44,7 @@ function shape.get_transformed(c, shape)
 
     -- Draw the client's shape in the middle
     cr:set_operator(cairo.Operator.SOURCE)
-    cr:set_source_surface(shape, border + l, border + t)
+    cr:set_source_surface(shape_img, border + l, border + t)
     cr:rectangle(border + l, border + t, geom.width - l - r, geom.height - t - b)
     cr:fill()
 
diff --git a/lib/awful/completion.lua b/lib/awful/completion.lua
index 4af7dd54..25537879 100644
--- a/lib/awful/completion.lua
+++ b/lib/awful/completion.lua
@@ -18,7 +18,6 @@ local math = math
 local print = print
 local pairs = pairs
 local string = string
-local util = require("awful.util")
 
 local completion = {}
 
@@ -128,7 +127,6 @@ function completion.shell(command, cur_pos, ncomp, shell)
     end
     local c, err = io.popen(shell_cmd .. " | sort -u")
     local output = {}
-    i = 0
     if c then
         while true do
             local line = c:read("*line")
@@ -168,7 +166,7 @@ end
 -- @param ncomp The number of yet requested completion using current text.
 -- @param keywords The keywords table uised for completion.
 -- @return The new match, the new cursor position, the table of all matches.
-function completion.generic(text, cur_pos, ncomp, keywords)
+function completion.generic(text, cur_pos, ncomp, keywords) -- luacheck: no unused args
     -- The keywords table may be empty
     if #keywords == 0 then
         return text, #text + 1
diff --git a/lib/awful/ewmh.lua b/lib/awful/ewmh.lua
index e02fe817..cd04c9ea 100644
--- a/lib/awful/ewmh.lua
+++ b/lib/awful/ewmh.lua
@@ -70,7 +70,6 @@ local function fullscreen(window, set)
     if set then
         store_geometry(window, "fullscreen")
         data[window].fullscreen.border_width = window.border_width
-        local g = screen[window.screen].geometry
         window:geometry(screen[window.screen].geometry)
         window.border_width = 0
     elseif data[window] and data[window].fullscreen then
@@ -163,7 +162,7 @@ end
 -- @tparam string context The context where this signal was used.
 -- @tparam[opt] table hints A table with additional hints:
 -- @tparam[opt=false] boolean hints.raise should the client be raised?
-function ewmh.activate(c, context, hints)
+function ewmh.activate(c, context, hints) -- luacheck: no unused args
     if c:isvisible() then
         client.focus = c
     end
diff --git a/lib/awful/hotkeys_popup/widget.lua b/lib/awful/hotkeys_popup/widget.lua
index 3e137def..85d61076 100644
--- a/lib/awful/hotkeys_popup/widget.lua
+++ b/lib/awful/hotkeys_popup/widget.lua
@@ -159,7 +159,7 @@ local function sort_hotkeys(target)
     for group, _ in pairs(group_list) do
         if target[group] then
             local sorted_table = {}
-            for index, key in pairs(target[group]) do
+            for _, key in pairs(target[group]) do
                 table.insert(sorted_table, key)
             end
             table.sort(
diff --git a/lib/awful/init.lua b/lib/awful/init.lua
index 52eab831..9ed82b11 100644
--- a/lib/awful/init.lua
+++ b/lib/awful/init.lua
@@ -10,7 +10,7 @@
 -- TODO: This is a hack for backwards-compatibility with 3.5, remove!
 local util = require("awful.util")
 local gtimer = require("gears.timer")
-function timer(...)
+function timer(...) -- luacheck: ignore
     util.deprecate("gears.timer")
     return gtimer(...)
 end
diff --git a/lib/awful/key.lua b/lib/awful/key.lua
index cd3b80ee..30feb5dc 100644
--- a/lib/awful/key.lua
+++ b/lib/awful/key.lua
@@ -54,10 +54,10 @@ function key.new(mod, _key, press, release, data)
         ret[#ret + 1] = capi.key({ modifiers = util.table.join(mod, set),
                                    key = _key })
         if press then
-            ret[#ret]:connect_signal("press", function(kobj, ...) press(...) end)
+            ret[#ret]:connect_signal("press", function(_, ...) press(...) end)
         end
         if release then
-            ret[#ret]:connect_signal("release", function(kobj, ...) release(...) end)
+            ret[#ret]:connect_signal("release", function(_, ...) release(...) end)
         end
     end
 
diff --git a/lib/awful/keygrabber.lua b/lib/awful/keygrabber.lua
index 1b08ca35..fd41bf08 100644
--- a/lib/awful/keygrabber.lua
+++ b/lib/awful/keygrabber.lua
@@ -20,7 +20,7 @@ local keygrabbing = false
 
 
 local function grabber(mod, key, event)
-    for i, keygrabber_function in ipairs(grabbers) do
+    for _, keygrabber_function in ipairs(grabbers) do
         -- continue if the grabber explicitly returns false
         if keygrabber_function(mod, key, event) ~= false then
             break
diff --git a/lib/awful/layout/init.lua b/lib/awful/layout/init.lua
index 742658c6..8921a9ab 100644
--- a/lib/awful/layout/init.lua
+++ b/lib/awful/layout/init.lua
@@ -75,7 +75,7 @@ function layout.inc(i, s, layouts)
         layouts, i, s = i, s, layouts
     end
     local t = tag.selected(s)
-    local layouts = layouts or layout.layouts
+    layouts = layouts or layout.layouts
     if t then
         local curlayout = layout.get(s)
         local curindex
@@ -192,7 +192,7 @@ end
 -- @param _layout The layout.
 -- @return The layout name.
 function layout.getname(_layout)
-    local _layout = _layout or layout.get()
+    _layout = _layout or layout.get()
     return _layout.name
 end
 
diff --git a/lib/awful/layout/suit/corner.lua b/lib/awful/layout/suit/corner.lua
index 2024f510..d8c672e0 100644
--- a/lib/awful/layout/suit/corner.lua
+++ b/lib/awful/layout/suit/corner.lua
@@ -109,7 +109,7 @@ local function do_corner(p, orientation)
     end
 
     for i, c in ipairs(cls) do
-        local g = nil
+        local g
         -- Handle master window
         if i == 1 then
             g = {
diff --git a/lib/awful/layout/suit/fair.lua b/lib/awful/layout/suit/fair.lua
index dcb3d368..3291530c 100644
--- a/lib/awful/layout/suit/fair.lua
+++ b/lib/awful/layout/suit/fair.lua
@@ -24,7 +24,7 @@ local function do_fair(p, orientation)
     end
 
     if #cls > 0 then
-        local rows, cols = 0, 0
+        local rows, cols
         if #cls == 2 then
             rows, cols = 1, 2
         else
@@ -36,11 +36,11 @@ local function do_fair(p, orientation)
             k = k - 1
             local g = {}
 
-            local row, col = 0, 0
+            local row, col
             row = k % rows
             col = math.floor(k / rows)
 
-            local lrows, lcols = 0, 0
+            local lrows, lcols
             if k >= rows * cols - rows then
                 lrows = #cls - (rows * cols - rows)
                 lcols = cols
diff --git a/lib/awful/layout/suit/floating.lua b/lib/awful/layout/suit/floating.lua
index d94672f3..b2037e43 100644
--- a/lib/awful/layout/suit/floating.lua
+++ b/lib/awful/layout/suit/floating.lua
@@ -8,7 +8,6 @@
 ---------------------------------------------------------------------------
 
 -- Grab environment we need
-local math = math
 local ipairs = ipairs
 local capi =
 {
@@ -44,7 +43,7 @@ function floating.mouse_resize_handler(c, corner, x, y)
     capi.mousegrabber.run(function (_mouse)
                               _mouse.x = _mouse.x + coordinates_delta.x
                               _mouse.y = _mouse.y + coordinates_delta.y
-                              for k, v in ipairs(_mouse.buttons) do
+                              for _, v in ipairs(_mouse.buttons) do
                                   if v then
                                       local ng
                                       prev_coords = { x =_mouse.x, y = _mouse.y }
diff --git a/lib/awful/layout/suit/magnifier.lua b/lib/awful/layout/suit/magnifier.lua
index 6f9bc7b0..32482369 100644
--- a/lib/awful/layout/suit/magnifier.lua
+++ b/lib/awful/layout/suit/magnifier.lua
@@ -32,7 +32,7 @@ function magnifier.mouse_resize_handler(c, corner, x, y)
 
     local prev_coords = {}
     capi.mousegrabber.run(function (_mouse)
-                              for k, v in ipairs(_mouse.buttons) do
+                              for _, v in ipairs(_mouse.buttons) do
                                   if v then
                                       prev_coords = { x =_mouse.x, y = _mouse.y }
                                       local dx = center_x - _mouse.x
@@ -126,13 +126,12 @@ function magnifier.arrange(p)
         -- Then move clients that are after focused client.
         -- So the next focused window will be the one at the top of the screen.
         for k = 1, fidx - 1 do
-            local g = {
+            p.geometries[cls[k]] = {
                 x = geometry.x,
                 y = geometry.y,
                 width = geometry.width,
                 height = geometry.height
             }
-            p.geometries[cls[k]] = g
             geometry.y = geometry.y + geometry.height
         end
     end
diff --git a/lib/awful/layout/suit/max.lua b/lib/awful/layout/suit/max.lua
index 6313724c..73603ab5 100644
--- a/lib/awful/layout/suit/max.lua
+++ b/lib/awful/layout/suit/max.lua
@@ -9,7 +9,6 @@
 
 -- Grab environment we need
 local pairs = pairs
-local client = require("awful.client")
 
 local max = {}
 
@@ -22,7 +21,7 @@ local function fmax(p, fs)
         area = p.workarea
     end
 
-    for k, c in pairs(p.clients) do
+    for _, c in pairs(p.clients) do
         local g = {
             x = area.x,
             y = area.y,
diff --git a/lib/awful/layout/suit/tile.lua b/lib/awful/layout/suit/tile.lua
index e8f0d3ee..0071ff56 100644
--- a/lib/awful/layout/suit/tile.lua
+++ b/lib/awful/layout/suit/tile.lua
@@ -26,8 +26,8 @@ local tile = {}
 --- Jump mouse cursor to the client's corner when resizing it.
 tile.resize_jump_to_corner = true
 
-local function mouse_resize_handler(c, corner, x, y, orientation)
-    local orientation = orientation or "tile"
+local function mouse_resize_handler(c, _, _, _, orientation)
+    orientation = orientation or "tile"
     local wa = capi.screen[c.screen].workarea
     local mwfact = tag.getmwfact()
     local cursor
@@ -87,47 +87,46 @@ local function mouse_resize_handler(c, corner, x, y, orientation)
     capi.mousegrabber.run(function (_mouse)
                               _mouse.x = _mouse.x + coordinates_delta.x
                               _mouse.y = _mouse.y + coordinates_delta.y
-                              for k, v in ipairs(_mouse.buttons) do
+                              for _, v in ipairs(_mouse.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
-                                      local mwfact
-
-                                      local g = c:geometry()
+                                      local new_mwfact
 
+                                      local geom = c:geometry()
 
                                       -- we have to make sure we're not on the last visible client where we have to use different settings.
                                       local wfact
                                       local wfact_x, wfact_y
-                                      if (g.y+g.height+15) > (wa.y+wa.height) then
-                                          wfact_y = (g.y + g.height - _mouse.y) / wa.height
+                                      if (geom.y+geom.height+15) > (wa.y+wa.height) then
+                                          wfact_y = (geom.y + geom.height - _mouse.y) / wa.height
                                       else
-                                          wfact_y = (_mouse.y - g.y) / wa.height
+                                          wfact_y = (_mouse.y - geom.y) / wa.height
                                       end
 
-                                      if (g.x+g.width+15) > (wa.x+wa.width) then
-                                          wfact_x = (g.x + g.width - _mouse.x) / wa.width
+                                      if (geom.x+geom.width+15) > (wa.x+wa.width) then
+                                          wfact_x = (geom.x + geom.width - _mouse.x) / wa.width
                                       else
-                                          wfact_x = (_mouse.x - g.x) / wa.width
+                                          wfact_x = (_mouse.x - geom.x) / wa.width
                                       end
 
 
                                       if orientation == "tile" then
-                                          mwfact = fact_x
+                                          new_mwfact = fact_x
                                           wfact = wfact_y
                                       elseif orientation == "left" then
-                                          mwfact = 1 - fact_x
+                                          new_mwfact = 1 - fact_x
                                           wfact = wfact_y
                                       elseif orientation == "bottom" then
-                                          mwfact = fact_y
+                                          new_mwfact = fact_y
                                           wfact = wfact_x
                                       else
-                                          mwfact = 1 - fact_y
+                                          new_mwfact = 1 - fact_y
                                           wfact = wfact_x
                                       end
 
-                                      tag.setmwfact(math.min(math.max(mwfact, 0.01), 0.99), tag.selected(c.screen))
+                                      tag.setmwfact(math.min(math.max(new_mwfact, 0.01), 0.99), tag.selected(c.screen))
                                       client.setwfact(math.min(math.max(wfact,0.01), 0.99), c)
                                       return true
                                   end
@@ -200,15 +199,11 @@ local function do_tile(param, orientation)
     orientation = orientation or "right"
 
     -- This handles all different orientations.
-    local height = "height"
     local width = "width"
     local x = "x"
-    local y = "y"
     if orientation == "top" or orientation == "bottom" then
-        height = "width"
         width = "height"
         x = "y"
-        y = "x"
     end
 
     local gs = param.geometries
@@ -236,7 +231,7 @@ local function do_tile(param, orientation)
 
     local grow_master = tag.getmfpol(t) == "expand"
     -- this was easier than writing functions because there is a lot of data we need
-    for d = 1,2 do
+    for _ = 1,2 do
         if place_master and nmaster > 0 then
             local size = wa[width]
             if nother > 0 or not grow_master then
diff --git a/lib/awful/menu.lua b/lib/awful/menu.lua
index c4a0af0f..2e29179d 100644
--- a/lib/awful/menu.lua
+++ b/lib/awful/menu.lua
@@ -99,7 +99,7 @@ end
 
 
 local function item_position(_menu, child)
-    local in_dir, other, a, b = 0, 0, "height", "width"
+    local a, b = "height", "width"
     local dir = _menu.layout.dir or "y"
     if dir == "x" then  a, b = b, a  end
 
@@ -191,7 +191,7 @@ local function check_access_key(_menu, key)
 end
 
 
-local function grabber(_menu, mod, key, event)
+local function grabber(_menu, _, key, event)
     if event ~= "press" then return end
 
     local sel = _menu.sel or 0
@@ -499,10 +499,10 @@ end
 --------------------------------------------------------------------------------
 
 --- Default awful.menu.entry constructor
--- @param parent The parent menu
+-- @param parent The parent menu (TODO: This is apparently unused)
 -- @param args the item params
 -- @return table with 'widget', 'cmd', 'akey' and all the properties the user wants to change
-function menu.entry(parent, args)
+function menu.entry(parent, args) -- luacheck: no unused args
     args = args or {}
     args.text = args[1] or args.text or ""
     args.cmd = args[2] or args.cmd
@@ -651,9 +651,9 @@ function menu.new(args, parent)
     end
 
     -- Create items
-    for i, v in ipairs(args) do  _menu:add(v)  end
+    for _, v in ipairs(args) do  _menu:add(v)  end
     if args.items then
-        for i, v in pairs(args.items) do  _menu:add(v)  end
+        for _, v in pairs(args.items) do  _menu:add(v)  end
     end
 
     _menu._keygrabber = function (...)
diff --git a/lib/awful/mouse/finder.lua b/lib/awful/mouse/finder.lua
index cb43692c..c3985a7d 100644
--- a/lib/awful/mouse/finder.lua
+++ b/lib/awful/mouse/finder.lua
@@ -38,12 +38,9 @@
 -- @module awful.mouse.finder
 -------------------------------------------------------------------------
 
-local mouse = mouse
-local screen = screen
 local timer = require("gears.timer")
 local wibox = require("wibox")
 local a_placement = require("awful.placement")
-local a_wibox = require("awful.wibox")
 local beautiful = require("beautiful")
 local setmetatable = setmetatable
 
diff --git a/lib/awful/mouse/init.lua b/lib/awful/mouse/init.lua
index 9d10c478..daa662d6 100644
--- a/lib/awful/mouse/init.lua
+++ b/lib/awful/mouse/init.lua
@@ -11,7 +11,6 @@
 local layout = require("awful.layout")
 local tag = require("awful.tag")
 local aclient = require("awful.client")
-local widget = require("awful.widget")
 local awibox = require("awful.wibox")
 local util = require("awful.util")
 local type = type
@@ -99,14 +98,13 @@ end
 -- @param fixed_x True if the client isn't allowed to move in the x direction.
 -- @param fixed_y True if the client isn't allowed to move in the y direction.
 function mouse.client.snap(c, snap, x, y, fixed_x, fixed_y)
-    local snap = snap or 8
-    local c = c or mouse.client.focus
+    snap = snap or 8
+    c = c or mouse.client.focus
     local cur_geom = c:geometry()
     local geom = c:geometry()
     geom.width = geom.width + (2 * c.border_width)
     geom.height = geom.height + (2 * c.border_width)
-    local edge = "none"
-    local edge2 = "none"
+    local edge
     geom.x = x or geom.x
     geom.y = y or geom.y
 
@@ -134,7 +132,7 @@ function mouse.client.snap(c, snap, x, y, fixed_x, fixed_y)
     geom.x = geom.x - (2 * c.border_width)
     geom.y = geom.y - (2 * c.border_width)
 
-    for k, snapper in ipairs(aclient.visible(c.screen)) do
+    for _, snapper in ipairs(aclient.visible(c.screen)) do
         if snapper ~= c then
             geom = snap_outside(geom, snapper:geometry(), snap)
         end
@@ -159,7 +157,7 @@ end
 --   when moving the client has been finished. The client
 --   that has been moved will be passed to that function.
 function mouse.client.move(c, snap, finished_cb)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
 
     if not c
         or c.fullscreen
@@ -178,7 +176,7 @@ function mouse.client.move(c, snap, finished_cb)
     local fixed_y = c.maximized_vertical
 
     capi.mousegrabber.run(function (_mouse)
-                              for k, v in ipairs(_mouse.buttons) do
+                              for _, v in ipairs(_mouse.buttons) do
                                   if v then
                                       local lay = layout.get(c.screen)
                                       if lay == layout.suit.floating or aclient.floating.get(c) then
@@ -259,7 +257,7 @@ end
 --- Move the wibox under the cursor
 --@param w The wibox to move, or none to use that under the pointer
 function mouse.wibox.move(w)
-    local w = w or mouse.wibox_under_pointer()
+    w = w or mouse.wibox_under_pointer()
     if not w then return end
 
     local offset = {
@@ -286,7 +284,7 @@ function mouse.wibox.move(w)
             end
             w.screen = capi.mouse.screen
         end
-        for k, v in ipairs(_mouse.buttons) do
+        for _, v in ipairs(_mouse.buttons) do
             if v then button_down = true end
         end
         if not button_down then
@@ -302,7 +300,7 @@ end
 -- bottom_right. Default is auto, and auto find the nearest corner.
 -- @return Actual used corner and x and y coordinates.
 function mouse.client.corner(c, corner)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     if not c then return end
 
     local g = c:geometry()
@@ -346,7 +344,7 @@ end
 -- @param c The client to resize, or the focused one by default.
 -- @param corner The corner to grab on resize. Auto detected by default.
 function mouse.client.resize(c, corner)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
 
     if not c then return end
 
@@ -358,12 +356,12 @@ function mouse.client.resize(c, corner)
     end
 
     local lay = layout.get(c.screen)
-    local corner, x, y = mouse.client.corner(c, corner)
+    local corner2, x, y = mouse.client.corner(c, corner)
 
     if lay == layout.suit.floating or aclient.floating.get(c) then
-        return layout.suit.floating.mouse_resize_handler(c, corner, x, y)
+        return layout.suit.floating.mouse_resize_handler(c, corner2, x, y)
     elseif lay.mouse_resize_handler then
-        return lay.mouse_resize_handler(c, corner, x, y)
+        return lay.mouse_resize_handler(c, corner2, x, y)
     end
 end
 
diff --git a/lib/awful/placement.lua b/lib/awful/placement.lua
index 0912aa6f..f7469c80 100644
--- a/lib/awful/placement.lua
+++ b/lib/awful/placement.lua
@@ -119,9 +119,9 @@ end
 -- @tparam[opt=client's screen] integer screen The screen.
 -- @treturn table The new client geometry.
 function placement.no_offscreen(c, screen)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     local geometry = get_area(c)
-    local screen   = screen or c.screen or a_screen.getbycoord(geometry.x, geometry.y)
+    screen = screen or c.screen or a_screen.getbycoord(geometry.x, geometry.y)
     local screen_geometry = capi.screen[screen].workarea
 
     if geometry.x + geometry.width > screen_geometry.x + screen_geometry.width then
@@ -149,7 +149,7 @@ function placement.no_overlap(c)
     local cls = client.visible(screen)
     local curlay = layout.get()
     local areas = { capi.screen[screen].workarea }
-    for i, cl in pairs(cls) do
+    for _, cl in pairs(cls) do
         if cl ~= c and cl.type ~= "desktop" and (client.floating.get(cl) or curlay == layout.suit.floating) then
             areas = area_remove(areas, get_area(cl))
         end
@@ -158,7 +158,7 @@ function placement.no_overlap(c)
     -- Look for available space
     local found = false
     local new = { x = geometry.x, y = geometry.y, width = 0, height = 0 }
-    for i, r in ipairs(areas) do
+    for _, r in ipairs(areas) do
         if r.width >= geometry.width
            and r.height >= geometry.height
            and r.width * r.height > new.width * new.height then
@@ -179,7 +179,7 @@ function placement.no_overlap(c)
     -- We did not find an area with enough space for our size:
     -- just take the biggest available one and go in
     if not found then
-        for i, r in ipairs(areas) do
+        for _, r in ipairs(areas) do
             if r.width * r.height > new.width * new.height then
                 new = r
             end
@@ -197,7 +197,7 @@ end
 -- @param c The client.
 -- @return The new client geometry.
 function placement.under_mouse(c)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     local c_geometry = get_area(c)
     local m_coords = capi.mouse.coords()
     return c:geometry({ x = m_coords.x - c_geometry.width / 2,
@@ -220,8 +220,10 @@ function placement.next_to_mouse(c, offset)
     local m_coords = capi.mouse.coords()
     local screen_geometry = capi.screen[capi.mouse.screen].workarea
 
+    local x, y
+
     -- Prefer it to be on the right.
-    local x = m_coords.x + offset
+    x = m_coords.x + offset
     if x + c_width > screen_geometry.width then
         -- Then to the left.
         x = m_coords.x - c_width - offset
@@ -245,7 +247,7 @@ end
 -- @param[opt] p The parent (nil for screen centering).
 -- @return The new client geometry.
 function placement.centered(c, p)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     local c_geometry = get_area(c)
     local screen = c.screen or a_screen.getbycoord(c_geometry.x, c_geometry.y)
     local s_geometry
@@ -263,7 +265,7 @@ end
 -- @param[opt] p The parent (nil for screen centering).
 -- @return The new client geometry.
 function placement.center_horizontal(c, p)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     local c_geometry = get_area(c)
     local screen = c.screen or a_screen.getbycoord(c_geometry.x, c_geometry.y)
     local s_geometry
@@ -280,7 +282,7 @@ end
 -- @param[opt] p The parent (nil for screen centering).
 -- @return The new client geometry.
 function placement.center_vertical(c, p)
-    local c = c or capi.client.focus
+    c = c or capi.client.focus
     local c_geometry = get_area(c)
     local screen = c.screen or a_screen.getbycoord(c_geometry.x, c_geometry.y)
     local s_geometry
diff --git a/lib/awful/prompt.lua b/lib/awful/prompt.lua
index 7223af95..91b745a0 100644
--- a/lib/awful/prompt.lua
+++ b/lib/awful/prompt.lua
@@ -290,9 +290,9 @@ function prompt.run(args, textbox, exe_callback, completion_callback, history_pa
     end
 
     -- Build the hook map
-    for k,v in ipairs(args.hooks or {}) do
+    for _,v in ipairs(args.hooks or {}) do
         if #v == 3 then
-            local mods,key,callback = unpack(v)
+            local _,key,callback = unpack(v)
             if type(callback) == "function" then
                 hooks[key] = hooks[key] or {}
                 hooks[key][#hooks[key]+1] = v
@@ -332,7 +332,7 @@ function prompt.run(args, textbox, exe_callback, completion_callback, history_pa
         if event ~= "press" then return end
         -- Convert index array to hash table
         local mod = {}
-        for k, v in ipairs(modifiers) do mod[v] = true end
+        for _, v in ipairs(modifiers) do mod[v] = true end
 
         -- Call the user specified callback. If it returns true as
         -- the first result then return from the function. Treat the
@@ -360,10 +360,10 @@ function prompt.run(args, textbox, exe_callback, completion_callback, history_pa
 
         -- User defined cases
         if hooks[key] then
-            for k,v in ipairs(hooks[key]) do
+            for _,v in ipairs(hooks[key]) do
                 if #modifiers == #v[1] then
                     local match = true
-                    for k2,v2 in ipairs(v[1]) do
+                    for _,v2 in ipairs(v[1]) do
                         match = match and mod[v2]
                     end
                     if match or #modifiers == 0 then
@@ -489,19 +489,19 @@ function prompt.run(args, textbox, exe_callback, completion_callback, history_pa
             elseif key == "w" or key == "BackSpace" then
                 local wstart = 1
                 local wend = 1
-                local cword_start = 1
-                local cword_end = 1
+                local cword_start_pos = 1
+                local cword_end_pos = 1
                 while wend < cur_pos do
                     wend = command:find("[{[(,.:;_-+=@/ ]", wstart)
                     if not wend then wend = #command + 1 end
                     if cur_pos >= wstart and cur_pos <= wend + 1 then
-                        cword_start = wstart
-                        cword_end = cur_pos - 1
+                        cword_start_pos = wstart
+                        cword_end_pos = cur_pos - 1
                         break
                     end
                     wstart = wend + 1
                 end
-                command = command:sub(1, cword_start - 1) .. command:sub(cword_end + 1)
+                command = command:sub(1, cword_start_pos - 1) .. command:sub(cword_end_pos + 1)
                 cur_pos = cword_start
             elseif key == "Delete" then
                 -- delete from history only if:
@@ -531,7 +531,7 @@ function prompt.run(args, textbox, exe_callback, completion_callback, history_pa
             elseif key == "d" then
                 command = command:sub(1, cur_pos - 1) .. command:sub(cword_end(command, cur_pos))
             elseif key == "BackSpace" then
-                wstart = cword_start(command, cur_pos)
+                local wstart = cword_start(command, cur_pos)
                 command = command:sub(1, wstart - 1) .. command:sub(cur_pos)
                 cur_pos = wstart
             end
diff --git a/lib/awful/remote.lua b/lib/awful/remote.lua
index 0f5188fa..d2b6bd95 100644
--- a/lib/awful/remote.lua
+++ b/lib/awful/remote.lua
@@ -9,11 +9,11 @@
 
 -- Grab environment we need
 require("awful.dbus")
-local load = loadstring or load -- v5.1 - loadstring, v5.2 - load
+local load = loadstring or load -- luacheck: globals loadstring (compatibility with Lua 5.1)
 local tostring = tostring
 local ipairs = ipairs
 local table = table
-local unpack = unpack or table.unpack -- v5.1: unpack, v5.2: table.unpack
+local unpack = unpack or table.unpack -- luacheck: globals unpack (compatibility with Lua 5.1)
 local dbus = dbus
 local type = type
 
diff --git a/lib/awful/rules.lua b/lib/awful/rules.lua
index 87b1c23e..26abc33e 100644
--- a/lib/awful/rules.lua
+++ b/lib/awful/rules.lua
@@ -213,6 +213,7 @@ function rules.execute(c, props, callbacks)
             c:geometry(geo);
         elseif property == "focus" then
             -- This will be handled below
+            (function() end)() -- I haven't found a nice way to silence luacheck here
         elseif type(c[property]) == "function" then
             c[property](c, value)
         else
@@ -222,7 +223,7 @@ function rules.execute(c, props, callbacks)
 
     -- Apply all callbacks.
     if callbacks then
-        for i, callback in pairs(callbacks) do
+        for _, callback in pairs(callbacks) do
             callback(c)
         end
     end
diff --git a/lib/awful/spawn.lua b/lib/awful/spawn.lua
index 09a0bd0f..9b5bd29e 100644
--- a/lib/awful/spawn.lua
+++ b/lib/awful/spawn.lua
@@ -110,7 +110,7 @@ function spawn.with_line_callback(cmd, callbacks)
     local stdout_callback, stderr_callback, done_callback, exit_callback =
         callbacks.stdout, callbacks.stderr, callbacks.output_done, callbacks.exit
     local have_stdout, have_stderr = stdout_callback ~= nil, stderr_callback ~= nil
-    local pid, sn_id, stdin, stdout, stderr = capi.awesome.spawn(cmd,
+    local pid, _, stdin, stdout, stderr = capi.awesome.spawn(cmd,
             false, false, have_stdout, have_stderr, exit_callback)
     if type(pid) == "string" then
         -- Error
diff --git a/lib/awful/tag.lua b/lib/awful/tag.lua
index 2c44f7f8..7ebcc61a 100644
--- a/lib/awful/tag.lua
+++ b/lib/awful/tag.lua
@@ -10,9 +10,7 @@
 -- Grab environment we need
 local util = require("awful.util")
 local ascreen = require("awful.screen")
-local timer = require("gears.timer")
 local beautiful = require("beautiful")
-local tostring = tostring
 local pairs = pairs
 local ipairs = ipairs
 local table = table
@@ -46,7 +44,7 @@ tag.history.limit = 20
 -- @param target_tag The tag that should be moved. If null, the currently
 -- selected tag is used.
 function tag.move(new_index, target_tag)
-    local target_tag = target_tag or tag.selected()
+    target_tag = target_tag or tag.selected()
     local scr = tag.getscreen(target_tag)
     local tmp_tags = tag.gettags(scr)
 
@@ -121,7 +119,7 @@ end
 -- @param layout The layout or layout table to set for this tags by default.
 -- @return A table with all created tags.
 function tag.new(names, screen, layout)
-    local screen = screen or 1
+    screen = screen or 1
     local tags = {}
     for id, name in ipairs(names) do
         table.insert(tags, id, tag.add(name, {screen = screen,
@@ -158,7 +156,7 @@ end
 -- history or select the first tag on the screen.
 function tag.delete(target_tag, fallback_tag)
     -- abort if no tag is passed or currently selected
-    local target_tag = target_tag or tag.selected()
+    target_tag = target_tag or tag.selected()
     if target_tag == nil or target_tag.activated == false then return end
 
     local target_scr = tag.getscreen(target_tag)
@@ -167,7 +165,6 @@ function tag.delete(target_tag, fallback_tag)
     local ntags      = #tags
 
     -- We can't use the target tag as a fallback.
-    local fallback_tag = fallback_tag
     if fallback_tag == target_tag then return end
 
     -- No fallback_tag provided, try and get one.
@@ -292,7 +289,7 @@ end
 -- @return A table with all available tags
 function tag.gettags(s)
     local tags = {}
-    for i, t in ipairs(root.tags()) do
+    for _, t in ipairs(root.tags()) do
         if tag.getscreen(t) == s then
             table.insert(tags, t)
         end
@@ -315,7 +312,7 @@ function tag.setscreen(s, t)
         s, t = t, s
     end
 
-    local s = s or ascreen.focused()
+    s = s or ascreen.focused()
     local sel = tag.selected
     local old_screen = tag.getproperty(t, "screen")
     if s == old_screen then return end
@@ -327,15 +324,15 @@ function tag.setscreen(s, t)
     tag.setproperty(t, "screen", s, true)
 
     -- Make sure the client's screen matches its tags
-    for k,c in ipairs(t:clients()) do
+    for _,c in ipairs(t:clients()) do
         c.screen = s --Move all clients
         c:tags({t})
     end
 
     -- Update all indexes
     for _,screen in ipairs {old_screen, s} do
-        for i,t in ipairs(tag.gettags(screen)) do
-            tag.setproperty(t, "index", i, true)
+        for i,t2 in ipairs(tag.gettags(screen)) do
+            tag.setproperty(t2, "index", i, true)
         end
     end
 
@@ -349,7 +346,7 @@ end
 -- @param[opt] t tag object
 -- @return Screen number
 function tag.getscreen(t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     return tag.getproperty(t, "screen")
 end
 
@@ -360,7 +357,7 @@ function tag.selectedlist(s)
     local screen = s or ascreen.focused()
     local tags = tag.gettags(screen)
     local vtags = {}
-    for i, t in pairs(tags) do
+    for _, t in pairs(tags) do
         if t.selected then
             vtags[#vtags + 1] = t
         end
@@ -378,7 +375,7 @@ end
 -- @param mwfact Master width factor.
 -- @param t The tag to modify, if null tag.selected() is used.
 function tag.setmwfact(mwfact, t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     if mwfact >= 0 and mwfact <= 1 then
         tag.setproperty(t, "mwfact", mwfact, true)
     end
@@ -394,7 +391,7 @@ end
 --- Get master width factor.
 -- @param[opt] t The tag.
 function tag.getmwfact(t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     return tag.getproperty(t, "mwfact") or 0.5
 end
 
@@ -438,7 +435,7 @@ end
 -- @param useless_gap The spacing between clients
 -- @param t The tag to modify, if null tag.selected() is used.
 function tag.setgap(useless_gap, t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     if useless_gap >= 0 then
         tag.setproperty(t, "useless_gap", useless_gap, true)
     end
@@ -457,7 +454,7 @@ end
 --   return 0 for a single client.  You can override this function to change
 --   this behavior.
 function tag.getgap(t, numclients)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     if numclients == 1 then
         return 0
     end
@@ -470,7 +467,7 @@ end
 -- "mwfact" (fill only an area inside the master width factor)
 -- @tparam[opt=tag.selected()] tag t The tag to modify
 function tag.setmfpol(policy, t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     tag.setproperty(t, "master_fill_policy", policy, true)
 end
 
@@ -491,7 +488,7 @@ end
 -- "expand" (fill all the available workarea, default one) or
 -- "mwfact" (fill only an area inside the master width factor)
 function tag.getmfpol(t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     return tag.getproperty(t, "master_fill_policy") or "expand"
 end
 
@@ -499,7 +496,7 @@ end
 -- @param nmaster The number of master windows.
 -- @param[opt] t The tag.
 function tag.setnmaster(nmaster, t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     if nmaster >= 0 then
         tag.setproperty(t, "nmaster", nmaster, true)
     end
@@ -508,7 +505,7 @@ end
 --- Get the number of master windows.
 -- @param[opt] t The tag.
 function tag.getnmaster(t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     return tag.getproperty(t, "nmaster") or 1
 end
 
@@ -542,14 +539,14 @@ end
 -- @param icon the icon to set, either path or image object
 -- @param _tag the tag
 function tag.seticon(icon, _tag)
-    local _tag = _tag or tag.selected()
+    _tag = _tag or tag.selected()
     tag.setproperty(_tag, "icon", icon, true)
 end
 
 --- Get the tag icon
 -- @param _tag the tag
 function tag.geticon(_tag)
-    local _tag = _tag or tag.selected()
+    _tag = _tag or tag.selected()
     return tag.getproperty(_tag, "icon")
 end
 
@@ -557,7 +554,7 @@ end
 -- @param ncol The number of column.
 -- @param t The tag to modify, if null tag.selected() is used.
 function tag.setncol(ncol, t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     if ncol >= 1 then
         tag.setproperty(t, "ncol", ncol, true)
     end
@@ -566,7 +563,7 @@ end
 --- Get number of column windows.
 -- @param[opt] t The tag.
 function tag.getncol(t)
-    local t = t or tag.selected()
+    t = t or tag.selected()
     return tag.getproperty(t, "ncol") or 1
 end
 
@@ -601,7 +598,7 @@ end
 -- @tparam[opt] int screen The screen number.
 function tag.viewnone(screen)
     local tags = tag.gettags(screen or ascreen.focused())
-    for i, t in pairs(tags) do
+    for _, t in pairs(tags) do
         t.selected = false
     end
 end
@@ -610,10 +607,10 @@ end
 -- @param i The relative index to see.
 -- @param[opt] screen The screen number.
 function tag.viewidx(i, screen)
-    local screen = screen or ascreen.focused()
+    screen = screen or ascreen.focused()
     local tags = tag.gettags(screen)
     local showntags = {}
-    for k, t in ipairs(tags) do
+    for _, t in ipairs(tags) do
         if not tag.getproperty(t, "hide") then
             table.insert(showntags, t)
         end
@@ -632,7 +629,7 @@ end
 -- @param query_tag The tag object to find. [selected()]
 -- @return The index of the tag, nil if the tag is not found.
 function tag.getidx(query_tag)
-    local query_tag = query_tag or tag.selected()
+    query_tag = query_tag or tag.selected()
     if query_tag == nil then return end
 
     for i, t in ipairs(tag.gettags(tag.getscreen(query_tag))) do
@@ -675,7 +672,7 @@ end
 -- @param tags A table with tags to view only.
 -- @param[opt] screen The screen number of the tags.
 function tag.viewmore(tags, screen)
-    local screen = screen or ascreen.focused()
+    screen = screen or ascreen.focused()
     local screen_tags = tag.gettags(screen)
     for _, _tag in ipairs(screen_tags) do
         if not util.table.hasitem(tags, _tag) then
@@ -738,7 +735,7 @@ end
 -- @param c The client to tag.
 function tag.withcurrent(c)
     local tags = {}
-    for k, t in ipairs(c:tags()) do
+    for _, t in ipairs(c:tags()) do
         if tag.getscreen(t) == c.screen then
             table.insert(tags, t)
         end
@@ -755,7 +752,7 @@ function tag.withcurrent(c)
 end
 
 local function attached_connect_signal_screen(screen, sig, func)
-    capi.tag.connect_signal(sig, function(_tag, ...)
+    capi.tag.connect_signal(sig, function(_tag)
         if tag.getscreen(_tag) == screen then
             func(_tag)
         end
@@ -792,7 +789,7 @@ capi.client.connect_signal("manage", function(c)
 end)
 
 -- Keep track of the number of urgent clients.
-local function update_urgent(c, t, modif)
+local function update_urgent(t, modif)
     local count = tag.getproperty(t, "urgent_count") or 0
     count = (count + modif) >= 0 and (count + modif) or 0
     tag.setproperty(t, "urgent"      , count > 0)
@@ -802,21 +799,21 @@ end
 -- Update the urgent counter when a client is tagged.
 local function client_tagged(c, t)
     if c.urgent then
-        update_urgent(c, t, 1)
+        update_urgent(t, 1)
     end
 end
 
 -- Update the urgent counter when a client is untagged.
 local function client_untagged(c, t)
     if c.urgent then
-        update_urgent(c, t, -1)
+        update_urgent(t, -1)
     end
 end
 
 -- Count the urgent clients.
 local function urgent_callback(c)
-    for k,t in ipairs(c:tags()) do
-        update_urgent(c, t, c.urgent and 1 or -1)
+    for _,t in ipairs(c:tags()) do
+        update_urgent(t, c.urgent and 1 or -1)
     end
 end
 
diff --git a/lib/awful/titlebar.lua b/lib/awful/titlebar.lua
index aedd9aef..d64b49e5 100644
--- a/lib/awful/titlebar.lua
+++ b/lib/awful/titlebar.lua
@@ -14,9 +14,7 @@ local abutton = require("awful.button")
 local aclient = require("awful.client")
 local atooltip = require("awful.tooltip")
 local beautiful = require("beautiful")
-local object = require("gears.object")
 local drawable = require("wibox.drawable")
-local base = require("wibox.widget.base")
 local imagebox = require("wibox.widget.imagebox")
 local textbox = require("wibox.widget.textbox")
 local capi = {
@@ -72,7 +70,7 @@ end
 -- can be configured via e.g. "bg_normal" and "bg_focus".
 -- @name titlebar
 local function new(c, args)
-    local args = args or {}
+    args = args or {}
     local position = args.position or "top"
     local size = args.size or util.round(beautiful.get_font_height(args.font) * 1.5)
     local d = get_titlebar_function(c, position)(c, size)
@@ -92,10 +90,10 @@ local function new(c, args)
         }
         ret = drawable(d, context, "awful.titlebar")
         local function update_colors()
-            local args = bars[position].args
-            ret:set_bg(get_color("bg", c, args))
-            ret:set_fg(get_color("fg", c, args))
-            ret:set_bgimage(get_color("bgimage", c, args))
+            local args_ = bars[position].args
+            ret:set_bg(get_color("bg", c, args_))
+            ret:set_fg(get_color("fg", c, args_))
+            ret:set_bgimage(get_color("bgimage", c, args_))
         end
 
         bars[position] = {
@@ -126,7 +124,7 @@ end
 -- @param[opt] position The position of the titlebar. Must be one of "left",
 --   "right", "top", "bottom". Default is "top".
 function titlebar.show(c, position)
-    local position = position or "top"
+    position = position or "top"
     local bars = all_titlebars[c]
     local data = bars and bars[position]
     local args = data and data.args
@@ -138,7 +136,7 @@ end
 -- @param[opt] position The position of the titlebar. Must be one of "left",
 --   "right", "top", "bottom". Default is "top".
 function titlebar.hide(c, position)
-    local position = position or "top"
+    position = position or "top"
     get_titlebar_function(c, position)(c, 0)
 end
 
@@ -147,8 +145,8 @@ end
 -- @param[opt] position The position of the titlebar. Must be one of "left",
 --   "right", "top", "bottom". Default is "top".
 function titlebar.toggle(c, position)
-    local position = position or "top"
-    local drawable, size = get_titlebar_function(c, position)(c)
+    position = position or "top"
+    local _, size = get_titlebar_function(c, position)(c)
     if size == 0 then
         titlebar.show(c, position)
     else
@@ -265,11 +263,11 @@ end
 --- Create a new maximize button for a client.
 -- @param c The client for which the button is wanted.
 function titlebar.widget.maximizedbutton(c)
-    local widget = titlebar.widget.button(c, "maximized", function(c)
-        return c.maximized_horizontal or c.maximized_vertical
-    end, function(c, state)
-        c.maximized_horizontal = not state
-        c.maximized_vertical = not state
+    local widget = titlebar.widget.button(c, "maximized", function(cl)
+        return cl.maximized_horizontal or cl.maximized_vertical
+    end, function(cl, state)
+        cl.maximized_horizontal = not state
+        cl.maximized_vertical = not state
     end)
     c:connect_signal("property::maximized_vertical", widget.update)
     c:connect_signal("property::maximized_horizontal", widget.update)
@@ -279,7 +277,7 @@ end
 --- Create a new minimize button for a client.
 -- @param c The client for which the button is wanted.
 function titlebar.widget.minimizebutton(c)
-    local widget = titlebar.widget.button(c, "minimize", function() return c.minimized end, function(c) c.minimized = not c.minimized end)
+    local widget = titlebar.widget.button(c, "minimize", function(cl) return cl.minimized end, function(cl) cl.minimized = not cl.minimized end)
     c:connect_signal("property::minimized", widget.update)
     return widget
 end
@@ -287,13 +285,13 @@ end
 --- Create a new closing button for a client.
 -- @param c The client for which the button is wanted.
 function titlebar.widget.closebutton(c)
-    return titlebar.widget.button(c, "close", function() return "" end, function(c) c:kill() end)
+    return titlebar.widget.button(c, "close", function() return "" end, function(cl) cl:kill() end)
 end
 
 --- Create a new ontop button for a client.
 -- @param c The client for which the button is wanted.
 function titlebar.widget.ontopbutton(c)
-    local widget = titlebar.widget.button(c, "ontop", function(c) return c.ontop end, function(c, state) c.ontop = not state end)
+    local widget = titlebar.widget.button(c, "ontop", function(cl) return cl.ontop end, function(cl, state) cl.ontop = not state end)
     c:connect_signal("property::ontop", widget.update)
     return widget
 end
@@ -301,7 +299,7 @@ end
 --- Create a new sticky button for a client.
 -- @param c The client for which the button is wanted.
 function titlebar.widget.stickybutton(c)
-    local widget = titlebar.widget.button(c, "sticky", function(c) return c.sticky end, function(c, state) c.sticky = not state end)
+    local widget = titlebar.widget.button(c, "sticky", function(cl) return cl.sticky end, function(cl, state) cl.sticky = not state end)
     c:connect_signal("property::sticky", widget.update)
     return widget
 end
diff --git a/lib/awful/tooltip.lua b/lib/awful/tooltip.lua
index 83899f3d..72af21fe 100644
--- a/lib/awful/tooltip.lua
+++ b/lib/awful/tooltip.lua
@@ -41,7 +41,6 @@
 -------------------------------------------------------------------------
 
 local mouse = mouse
-local screen = screen
 local timer = require("gears.timer")
 local wibox = require("wibox")
 local a_placement = require("awful.placement")
diff --git a/lib/awful/util.lua b/lib/awful/util.lua
index 4157c32a..cd61fea5 100644
--- a/lib/awful/util.lua
+++ b/lib/awful/util.lua
@@ -11,14 +11,13 @@
 local os = os
 local io = io
 local assert = assert
-local load = loadstring or load -- v5.1 - loadstring, v5.2 - load
+local load = loadstring or load -- luacheck: globals loadstring (compatibility with Lua 5.1)
 local loadfile = loadfile
 local debug = debug
 local pairs = pairs
 local ipairs = ipairs
 local type = type
 local rtable = table
-local pairs = pairs
 local string = string
 local lgi = require("lgi")
 local Gio = require("lgi").Gio
@@ -195,8 +194,8 @@ end
 -- @tparam[opt] string size The size. If this is specified, subdirectories `x`
 --   of the dirs are searched first.
 function util.geticonpath(iconname, exts, dirs, size)
-    local exts = exts or { 'png', 'gif' }
-    local dirs = dirs or { '/usr/share/pixmaps/', '/usr/share/icons/hicolor/' }
+    exts = exts or { 'png', 'gif' }
+    dirs = dirs or { '/usr/share/pixmaps/', '/usr/share/icons/hicolor/' }
     local icontypes = { 'apps', 'actions',  'categories',  'emblems',
         'mimetypes',  'status', 'devices', 'extras', 'places', 'stock' }
     for _, d in pairs(dirs) do
@@ -385,7 +384,7 @@ end
 -- @return A new table containing all keys from the arguments.
 function util.table.join(...)
     local ret = {}
-    for i, t in pairs({...}) do
+    for _, t in pairs({...}) do
         if t then
             for k, v in pairs(t) do
                 if type(k) == "number" then
@@ -422,7 +421,7 @@ end
 -- @treturn table A packed table with all numeric keys
 function util.table.from_sparse(t)
     local keys= {}
-    for k,v in pairs(t) do
+    for k in pairs(t) do
         if type(k) == "number" then
             keys[#keys+1] = k
         end
@@ -462,7 +461,7 @@ function util.linewrap(text, width, indent)
 
     local pos = 1
     return text:gsub("(%s+)()(%S+)()",
-        function(sp, st, word, fi)
+        function(_, st, word, fi)
             if fi - pos > width then
                 pos = st
                 return "\n" .. string.rep(" ", indent) .. word
@@ -532,7 +531,7 @@ end
 -- @param deep Create a deep clone? (default: true)
 -- @return a clone of t
 function util.table.clone(t, deep)
-    local deep = deep == nil and true or deep
+    deep = deep == nil and true or deep
     local c = { }
     for k, v in pairs(t) do
         if deep and type(v) == "table" then
@@ -592,7 +591,7 @@ end
 -- Generate a pattern matching expression that ignores case.
 -- @param s Original pattern matching expression.
 function util.query_to_pattern(q)
-    s = util.quote_pattern(q)
+    local s = util.quote_pattern(q)
     -- Poor man's case-insensitive character matching.
     s = string.gsub(s, "%a",
                     function (c)
diff --git a/lib/awful/wibox.lua b/lib/awful/wibox.lua
index 462afe44..7d7978b2 100644
--- a/lib/awful/wibox.lua
+++ b/lib/awful/wibox.lua
@@ -32,11 +32,11 @@ local awfulwibox = { mt = {} }
 local wiboxes = {}
 
 --- Get a wibox position if it has been set, or return top.
--- @param wibox The wibox
+-- @param wb The wibox
 -- @return The wibox position.
-function awfulwibox.get_position(wibox)
+function awfulwibox.get_position(wb)
     for _, wprop in ipairs(wiboxes) do
-        if wprop.wibox == wibox then
+        if wprop.wibox == wb then
             return wprop.position
         end
     end
@@ -44,28 +44,28 @@ function awfulwibox.get_position(wibox)
 end
 
 --- Put a wibox on a screen at this position.
--- @param wibox The wibox to attach.
+-- @param wb The wibox to attach.
 -- @param position The position: top, bottom left or right.
 -- @param screen If the wibox it not attached to a screen, specified on which
 -- screen the position should be set.
-function awfulwibox.set_position(wibox, position, screen)
+function awfulwibox.set_position(wb, position, screen)
     local area = capi.screen[screen].geometry
 
     -- The "length" of a wibox is always chosen to be the optimal size
     -- (non-floating).
     -- The "width" of a wibox is kept if it exists.
     if position == "right" then
-        wibox.x = area.x + area.width - (wibox.width + 2 * wibox.border_width)
+        wb.x = area.x + area.width - (wb.width + 2 * wb.border_width)
     elseif position == "left" then
-        wibox.x = area.x
+        wb.x = area.x
     elseif position == "bottom" then
-        wibox.y = (area.y + area.height) - (wibox.height + 2 * wibox.border_width)
+        wb.y = (area.y + area.height) - (wb.height + 2 * wb.border_width)
     elseif position == "top" then
-        wibox.y = area.y
+        wb.y = area.y
     end
 
     for _, wprop in ipairs(wiboxes) do
-        if wprop.wibox == wibox then
+        if wprop.wibox == wb then
             wprop.position = position
             break
         end
@@ -79,23 +79,23 @@ local function update_all_wiboxes_position()
     end
 end
 
-local function call_wibox_position_hook_on_prop_update(w)
+local function call_wibox_position_hook_on_prop_update()
     update_all_wiboxes_position()
 end
 
-local function wibox_update_strut(wibox)
+local function wibox_update_strut(wb)
     for _, wprop in ipairs(wiboxes) do
-        if wprop.wibox == wibox then
-            if not wibox.visible then
-                wibox:struts { left = 0, right = 0, bottom = 0, top = 0 }
+        if wprop.wibox == wb then
+            if not wb.visible then
+                wb:struts { left = 0, right = 0, bottom = 0, top = 0 }
             elseif wprop.position == "top" then
-                wibox:struts { left = 0, right = 0, bottom = 0, top = wibox.height + 2 * wibox.border_width }
+                wb:struts { left = 0, right = 0, bottom = 0, top = wb.height + 2 * wb.border_width }
             elseif wprop.position == "bottom" then
-                wibox:struts { left = 0, right = 0, bottom = wibox.height + 2 * wibox.border_width, top = 0 }
+                wb:struts { left = 0, right = 0, bottom = wb.height + 2 * wb.border_width, top = 0 }
             elseif wprop.position == "left" then
-                wibox:struts { left = wibox.width + 2 * wibox.border_width, right = 0, bottom = 0, top = 0 }
+                wb:struts { left = wb.width + 2 * wb.border_width, right = 0, bottom = 0, top = 0 }
             elseif wprop.position == "right" then
-                wibox:struts { left = 0, right = wibox.width + 2 * wibox.border_width, bottom = 0, top = 0 }
+                wb:struts { left = 0, right = wb.width + 2 * wb.border_width, bottom = 0, top = 0 }
             end
             break
         end
@@ -105,10 +105,10 @@ end
 --- Attach a wibox to a screen.
 -- If a wibox is attached, it will be automatically be moved when other wiboxes
 -- will be attached.
--- @param wibox The wibox to attach.
+-- @param wb The wibox to attach.
 -- @param position The position of the wibox: top, bottom, left or right.
 -- @param screen TODO, this seems to be unused
-function awfulwibox.attach(wibox, position, screen)
+function awfulwibox.attach(wb, position, screen)
     -- Store wibox as attached in a weak-valued table
     local wibox_prop_table
     -- Start from end since we sometimes remove items
@@ -117,7 +117,7 @@ function awfulwibox.attach(wibox, position, screen)
         -- If they did, remove their entries
         if wiboxes[i].wibox == nil then
             table.remove(wiboxes, i)
-        elseif wiboxes[i].wibox == wibox then
+        elseif wiboxes[i].wibox == wb then
             wibox_prop_table = wiboxes[i]
             -- We could break here, but well, let's check if there is no other
             -- table with their wiboxes been garbage collected.
@@ -125,81 +125,81 @@ function awfulwibox.attach(wibox, position, screen)
     end
 
     if not wibox_prop_table then
-        table.insert(wiboxes, setmetatable({ wibox = wibox, position = position, screen = screen }, { __mode = 'v' }))
+        table.insert(wiboxes, setmetatable({ wibox = wb, position = position, screen = screen }, { __mode = 'v' }))
     else
         wibox_prop_table.position = position
     end
 
-    wibox:connect_signal("property::width", wibox_update_strut)
-    wibox:connect_signal("property::height", wibox_update_strut)
-    wibox:connect_signal("property::visible", wibox_update_strut)
+    wb:connect_signal("property::width", wibox_update_strut)
+    wb:connect_signal("property::height", wibox_update_strut)
+    wb:connect_signal("property::visible", wibox_update_strut)
 
-    wibox:connect_signal("property::width", call_wibox_position_hook_on_prop_update)
-    wibox:connect_signal("property::height", call_wibox_position_hook_on_prop_update)
-    wibox:connect_signal("property::visible", call_wibox_position_hook_on_prop_update)
-    wibox:connect_signal("property::border_width", call_wibox_position_hook_on_prop_update)
+    wb:connect_signal("property::width", call_wibox_position_hook_on_prop_update)
+    wb:connect_signal("property::height", call_wibox_position_hook_on_prop_update)
+    wb:connect_signal("property::visible", call_wibox_position_hook_on_prop_update)
+    wb:connect_signal("property::border_width", call_wibox_position_hook_on_prop_update)
 end
 
 --- Align a wibox.
--- @param wibox The wibox.
+-- @param wb The wibox.
 -- @param align The alignment: left, right or center.
 -- @param screen If the wibox is not attached to any screen, you can specify the
 -- screen where to align. Otherwise 1 is assumed.
-function awfulwibox.align(wibox, align, screen)
-    local position = awfulwibox.get_position(wibox)
+function awfulwibox.align(wb, align, screen)
+    local position = awfulwibox.get_position(wb)
     local area = capi.screen[screen].workarea
 
     if position == "right" then
         if align == "right" then
-            wibox.y = area.y
+            wb.y = area.y
         elseif align == "left" then
-            wibox.y = area.y + area.height - (wibox.height + 2 * wibox.border_width)
+            wb.y = area.y + area.height - (wb.height + 2 * wb.border_width)
         elseif align == "center" then
-            wibox.y = area.y + round((area.height - wibox.height) / 2)
+            wb.y = area.y + round((area.height - wb.height) / 2)
         end
     elseif position == "left" then
         if align == "right" then
-            wibox.y = (area.y + area.height) - (wibox.height + 2 * wibox.border_width)
+            wb.y = (area.y + area.height) - (wb.height + 2 * wb.border_width)
         elseif align == "left" then
-            wibox.y = area.y
+            wb.y = area.y
         elseif align == "center" then
-            wibox.y = area.y + round((area.height - wibox.height) / 2)
+            wb.y = area.y + round((area.height - wb.height) / 2)
         end
     elseif position == "bottom" then
         if align == "right" then
-            wibox.x = area.x + area.width - (wibox.width + 2 * wibox.border_width)
+            wb.x = area.x + area.width - (wb.width + 2 * wb.border_width)
         elseif align == "left" then
-            wibox.x = area.x
+            wb.x = area.x
         elseif align == "center" then
-            wibox.x = area.x + round((area.width - wibox.width) / 2)
+            wb.x = area.x + round((area.width - wb.width) / 2)
         end
     elseif position == "top" then
         if align == "right" then
-            wibox.x = area.x + area.width - (wibox.width + 2 * wibox.border_width)
+            wb.x = area.x + area.width - (wb.width + 2 * wb.border_width)
         elseif align == "left" then
-            wibox.x = area.x
+            wb.x = area.x
         elseif align == "center" then
-            wibox.x = area.x + round((area.width - wibox.width) / 2)
+            wb.x = area.x + round((area.width - wb.width) / 2)
         end
     end
 
     -- Update struts regardless of changes
-    wibox_update_strut(wibox)
+    wibox_update_strut(wb)
 end
 
 --- Stretch a wibox so it takes all screen width or height.
--- @param wibox The wibox.
+-- @param wb The wibox.
 -- @param screen The screen to stretch on, or the wibox screen.
-function awfulwibox.stretch(wibox, screen)
+function awfulwibox.stretch(wb, screen)
     if screen then
-        local position = awfulwibox.get_position(wibox)
+        local position = awfulwibox.get_position(wb)
         local area = capi.screen[screen].workarea
         if position == "right" or position == "left" then
-            wibox.height = area.height - (2 * wibox.border_width)
-            wibox.y = area.y
+            wb.height = area.height - (2 * wb.border_width)
+            wb.y = area.y
         else
-            wibox.width = area.width - (2 * wibox.border_width)
-            wibox.x = area.x
+            wb.width = area.width - (2 * wb.border_width)
+            wb.x = area.x
         end
     end
 end
@@ -213,7 +213,7 @@ end
 -- If not specified, 1 is assumed.
 -- @return The wibox created.
 function awfulwibox.new(arg)
-    local arg = arg or {}
+    arg = arg or {}
     local position = arg.position or "top"
     local has_to_stretch = true
     local screen = arg.screen or 1
diff --git a/lib/awful/widget/button.lua b/lib/awful/widget/button.lua
index 25f2da64..8189bfc3 100644
--- a/lib/awful/widget/button.lua
+++ b/lib/awful/widget/button.lua
@@ -6,13 +6,11 @@
 ---------------------------------------------------------------------------
 
 local setmetatable = setmetatable
-local type = type
 local abutton = require("awful.button")
 local imagebox = require("wibox.widget.imagebox")
 local widget = require("wibox.widget.base")
 local surface = require("gears.surface")
 local cairo = require("lgi").cairo
-local capi = { mouse = mouse }
 
 local button = { mt = {} }
 
@@ -31,13 +29,13 @@ function button.new(args)
     local img_release
     local img_press
 
-    w.set_image = function(w, image)
+    function w:set_image(image)
         img_release = surface.load(image)
         img_press = img_release:create_similar(cairo.Content.COLOR_ALPHA, img_release.width, img_release.height)
         local cr = cairo.Context(img_press)
         cr:set_source_surface(img_release, 2, 2)
         cr:paint()
-        orig_set_image(w, img_release)
+        orig_set_image(self, img_release)
     end
     w:set_image(args.image)
     w:buttons(abutton({}, 1, function () orig_set_image(w, img_press) end, function () orig_set_image(w, img_release) end))
diff --git a/lib/awful/widget/common.lua b/lib/awful/widget/common.lua
index ebab6337..ba9999c8 100644
--- a/lib/awful/widget/common.lua
+++ b/lib/awful/widget/common.lua
@@ -6,17 +6,10 @@
 ---------------------------------------------------------------------------
 
 -- Grab environment we need
-local math = math
 local type = type
 local ipairs = ipairs
-local pairs = pairs
-local pcall = pcall
-local setmetatable = setmetatable
 local capi = { button = button }
-local util = require("awful.util")
 local wibox = require("wibox")
-local imagebox = require("wibox.widget.imagebox")
-local textbox = require("wibox.widget.textbox")
 local dpi = require("beautiful").xresources.apply_dpi
 
 --- Common utilities for awful widgets
@@ -29,7 +22,7 @@ local common = {}
 function common.create_buttons(buttons, object)
     if buttons then
         local btns = {}
-        for kb, b in ipairs(buttons) do
+        for _, b in ipairs(buttons) do
             -- Create a proxy button object: it will receive the real
             -- press and release events, and will propagate them the the
             -- button object the user provided, but with the object as
diff --git a/lib/awful/widget/graph.lua b/lib/awful/widget/graph.lua
index fdd83198..73d14cea 100644
--- a/lib/awful/widget/graph.lua
+++ b/lib/awful/widget/graph.lua
@@ -69,7 +69,7 @@ local properties = { "width", "height", "border_color", "stack",
                      "stack_colors", "color", "background_color",
                      "max_value", "scale" }
 
-function graph.draw(_graph, context, cr, width, height)
+function graph.draw(_graph, _, cr, width, height)
     local max_value = data[_graph].max_value
     local values = data[_graph].values
 
@@ -91,7 +91,7 @@ function graph.draw(_graph, context, cr, width, height)
 
         if data[_graph].scale then
             for _, v in ipairs(values) do
-                for __, sv in ipairs(v) do
+                for _, sv in ipairs(v) do
                     if sv > max_value then
                         max_value = sv
                     end
@@ -169,7 +169,7 @@ end
 local function add_value(_graph, value, group)
     if not _graph then return end
 
-    local value = value or 0
+    value = value or 0
     local values = data[_graph].values
     local max_value = data[_graph].max_value
     value = math.max(0, value)
@@ -243,7 +243,7 @@ end
 -- key to set graph geometry.
 -- @return A graph widget.
 function graph.new(args)
-    local args = args or {}
+    args = args or {}
 
     local width = args.width or 100
     local height = args.height or 20
diff --git a/lib/awful/widget/keyboardlayout.lua b/lib/awful/widget/keyboardlayout.lua
index 2c58f9c6..b3b83762 100644
--- a/lib/awful/widget/keyboardlayout.lua
+++ b/lib/awful/widget/keyboardlayout.lua
@@ -7,7 +7,6 @@
 
 local capi = {awesome = awesome}
 local setmetatable = setmetatable
-local os = os
 local textbox = require("wibox.widget.textbox")
 local button = require("awful.button")
 local util = require("awful.util")
@@ -264,8 +263,7 @@ function keyboardlayout.new()
     update_layout(self);
 
     self.next_layout = function()
-        new_layout = (self._current + 1) % (#self._layout + 1)
-        self.set_layout(new_layout)
+        self.set_layout((self._current + 1) % (#self._layout + 1))
     end
 
     self.set_layout = function(group_number)
diff --git a/lib/awful/widget/layoutbox.lua b/lib/awful/widget/layoutbox.lua
index 2434ab77..11e7fcaf 100644
--- a/lib/awful/widget/layoutbox.lua
+++ b/lib/awful/widget/layoutbox.lua
@@ -8,8 +8,6 @@
 ---------------------------------------------------------------------------
 
 local setmetatable = setmetatable
-local ipairs = ipairs
-local button = require("awful.button")
 local layout = require("awful.layout")
 local tooltip = require("awful.tooltip")
 local tag = require("awful.tag")
@@ -21,9 +19,9 @@ local layoutbox = { mt = {} }
 local boxes = nil
 
 local function update(w, screen)
-    local layout = layout.getname(layout.get(screen))
-    w._layoutbox_tooltip:set_text(layout or "[no name]")
-    w:set_image(layout and beautiful["layout_" .. layout])
+    local name = layout.getname(layout.get(screen))
+    w._layoutbox_tooltip:set_text(name or "[no name]")
+    w:set_image(name and beautiful["layout_" .. name])
 end
 
 local function update_from_tag(t)
@@ -39,7 +37,7 @@ end
 -- @param screen The screen number that the layout will be represented for.
 -- @return An imagebox widget configured as a layoutbox.
 function layoutbox.new(screen)
-    local screen = screen or 1
+    screen = screen or 1
 
     -- Do we already have the update callbacks registered?
     if boxes == nil then
diff --git a/lib/awful/widget/progressbar.lua b/lib/awful/widget/progressbar.lua
index 4932207b..4eb5ccbf 100644
--- a/lib/awful/widget/progressbar.lua
+++ b/lib/awful/widget/progressbar.lua
@@ -71,7 +71,7 @@ local properties = { "width", "height", "border_color",
                      "vertical", "value", "max_value",
                      "ticks", "ticks_gap", "ticks_size" }
 
-function progressbar.draw(pbar, context, cr, width, height)
+function progressbar.draw(pbar, _, cr, width, height)
     local ticks_gap = data[pbar].ticks_gap or 1
     local ticks_size = data[pbar].ticks_size or 4
 
@@ -161,7 +161,7 @@ end
 --- Set the progressbar value.
 -- @param value The progress bar value between 0 and 1.
 function progressbar:set_value(value)
-    local value = value or 0
+    value = value or 0
     local max_value = data[self].max_value
     data[self].value = math.min(max_value, math.max(0, value))
     self:emit_signal("widget::redraw_needed")
@@ -200,7 +200,7 @@ end
 -- key to set progressbar geometry.
 -- @return A progressbar widget.
 function progressbar.new(args)
-    local args = args or {}
+    args = args or {}
     local width = args.width or 100
     local height = args.height or 20
 
diff --git a/lib/awful/widget/prompt.lua b/lib/awful/widget/prompt.lua
index ef4af3d3..e242acac 100644
--- a/lib/awful/widget/prompt.lua
+++ b/lib/awful/widget/prompt.lua
@@ -42,7 +42,7 @@ end
 -- @param args Arguments table. "prompt" is the prompt to use.
 -- @return A launcher widget.
 function widgetprompt.new(args)
-    local args = args or {}
+    args = args or {}
     local widget = textbox()
     local promptbox = widget_base.make_widget(widget)
 
diff --git a/lib/awful/widget/taglist.lua b/lib/awful/widget/taglist.lua
index f632a861..4aeff6e7 100644
--- a/lib/awful/widget/taglist.lua
+++ b/lib/awful/widget/taglist.lua
@@ -11,7 +11,6 @@
 local capi = { screen = screen,
                awesome = awesome,
                client = client }
-local type = type
 local setmetatable = setmetatable
 local pairs = pairs
 local ipairs = ipairs
@@ -53,7 +52,8 @@ function taglist.taglist_label(t, args)
     local fg_color = nil
     local bg_image
     local icon
-    local bg_resize = false
+    -- TODO: Re-implement bg_resize
+    local bg_resize = false -- luacheck: ignore
     local is_selected = false
     local cls = t:clients()
 
@@ -117,7 +117,7 @@ end
 
 local function taglist_update(s, w, buttons, filter, data, style, update_function)
     local tags = {}
-    for k, t in ipairs(tag.gettags(s)) do
+    for _, t in ipairs(tag.gettags(s)) do
         if not tag.getproperty(t, "hide") and filter(t) then
             table.insert(tags, t)
         end
@@ -211,25 +211,21 @@ end
 
 --- Filtering function to include all nonempty tags on the screen.
 -- @param t The tag.
--- @param args unused list of extra arguments.
 -- @return true if t is not empty, else false
-function taglist.filter.noempty(t, args)
+function taglist.filter.noempty(t)
     return #t:clients() > 0 or t.selected
 end
 
 --- Filtering function to include selected tags on the screen.
 -- @param t The tag.
--- @param args unused list of extra arguments.
 -- @return true if t is not empty, else false
-function taglist.filter.selected(t, args)
+function taglist.filter.selected(t)
     return t.selected
 end
 
 --- Filtering function to include all tags on the screen.
--- @param t The tag.
--- @param args unused list of extra arguments.
 -- @return true
-function taglist.filter.all(t, args)
+function taglist.filter.all()
     return true
 end
 
diff --git a/lib/awful/widget/tasklist.lua b/lib/awful/widget/tasklist.lua
index ccae7fa1..5c0294e1 100644
--- a/lib/awful/widget/tasklist.lua
+++ b/lib/awful/widget/tasklist.lua
@@ -48,10 +48,10 @@ local function tasklist_label(c, args, tb)
     local font_focus = args.font_focus or theme.tasklist_font_focus or theme.font_focus or font or ""
     local font_minimized = args.font_minimized or theme.tasklist_font_minimized or theme.font_minimized or font or ""
     local font_urgent = args.font_urgent or theme.tasklist_font_urgent or theme.font_urgent or font or ""
-    local bg = nil
     local text = ""
     local name = ""
-    local bg_image = nil
+    local bg
+    local bg_image
 
     -- symbol to use to indicate certain client properties
     local sticky = args.sticky or theme.tasklist_sticky or "▪"
@@ -89,8 +89,8 @@ local function tasklist_label(c, args, tb)
     -- is considered to be focused, if the real client has skip_taskbar.
     if not focused and capi.client.focus and capi.client.focus.skip_taskbar
         and client.get_transient_for_matching(capi.client.focus,
-                                              function(c)
-                                                  return not c.skip_taskbar
+                                              function(cl)
+                                                  return not cl.skip_taskbar
                                               end) == c then
         focused = true
     end
@@ -120,7 +120,7 @@ end
 
 local function tasklist_update(s, w, buttons, filter, data, style, update_function)
     local clients = {}
-    for k, c in ipairs(capi.client.get()) do
+    for _, c in ipairs(capi.client.get()) do
         if not (c.skip_taskbar or c.hidden
             or c.type == "splash" or c.type == "dock" or c.type == "desktop")
             and filter(c, s) then
@@ -245,10 +245,8 @@ function tasklist.new(screen, filter, buttons, style, update_function, base_widg
 end
 
 --- Filtering function to include all clients.
--- @param c The client.
--- @param screen The screen we are drawing on.
 -- @return true
-function tasklist.filter.allscreen(c, screen)
+function tasklist.filter.allscreen()
     return true
 end
 
@@ -271,7 +269,7 @@ function tasklist.filter.currenttags(c, screen)
     -- Include sticky client too
     if c.sticky then return true end
     local tags = tag.gettags(screen)
-    for k, t in ipairs(tags) do
+    for _, t in ipairs(tags) do
         if t.selected then
             local ctags = c:tags()
             for _, v in ipairs(ctags) do
@@ -296,7 +294,7 @@ function tasklist.filter.minimizedcurrenttags(c, screen)
     -- Include sticky client
     if c.sticky then return true end
     local tags = tag.gettags(screen)
-    for k, t in ipairs(tags) do
+    for _, t in ipairs(tags) do
         -- Select only minimized clients
         if t.selected then
             local ctags = c:tags()
diff --git a/lib/awful/widget/textclock.lua b/lib/awful/widget/textclock.lua
index 6b5d708e..a4a0f90c 100644
--- a/lib/awful/widget/textclock.lua
+++ b/lib/awful/widget/textclock.lua
@@ -27,8 +27,8 @@ end
 -- @param timeout How often update the time. Default is 60.
 -- @return A textbox widget.
 function textclock.new(format, timeout)
-    local format = format or " %a %b %d, %H:%M "
-    local timeout = timeout or 60
+    format = format or " %a %b %d, %H:%M "
+    timeout = timeout or 60
 
     local w = textbox()
     local t
diff --git a/lib/beautiful/init.lua b/lib/beautiful/init.lua
index e3aee501..7725f310 100644
--- a/lib/beautiful/init.lua
+++ b/lib/beautiful/init.lua
@@ -10,22 +10,13 @@
 
 -- Grab environment
 local os = os
-local print = print
-local pcall = pcall
 local pairs = pairs
 local type = type
 local dofile = dofile
 local setmetatable = setmetatable
-local util = require("awful.util")
 local lgi = require("lgi")
-local cairo = lgi.cairo
 local Pango = lgi.Pango
 local PangoCairo = lgi.PangoCairo
-local capi =
-{
-    screen = screen,
-    awesome = awesome
-}
 local gears_debug = require("gears.debug")
 
 local xresources = require("beautiful.xresources")
@@ -99,7 +90,7 @@ end
 -- @treturn lgi.Pango.FontDescription
 function beautiful.get_merged_font(name, merge)
     local font = beautiful.get_font(name)
-    local merge = Pango.FontDescription.from_string(merge)
+    merge = Pango.FontDescription.from_string(merge)
     local merged = font:copy_static()
     merged:merge(merge, true)
     return beautiful.get_font(merged:to_string())
diff --git a/lib/beautiful/xresources.lua b/lib/beautiful/xresources.lua
index 2ec90a98..d9b174b9 100644
--- a/lib/beautiful/xresources.lua
+++ b/lib/beautiful/xresources.lua
@@ -8,7 +8,6 @@
 ----------------------------------------------------------------------------
 
 -- Grab environment
-local print = print
 local awesome = awesome
 local round = require("awful.util").round
 local gears_debug = require("gears.debug")
diff --git a/lib/menubar/icon_theme.lua b/lib/menubar/icon_theme.lua
index eab2f32a..768db7c7 100644
--- a/lib/menubar/icon_theme.lua
+++ b/lib/menubar/icon_theme.lua
@@ -21,21 +21,6 @@ local setmetatable = setmetatable
 local string = string
 local table = table
 local math = math
-local io = io
-
--- Returns a table whose element is a path used for icon lookup.
--- The names of the directories and the order of them are based on the spec.
-local get_default_base_directories = function()
-    local dirs = {}
-
-    table.insert(dirs, GLib.get_home_dir() .. "/.icons")
-    for _, dir in ipairs(GLib.get_system_data_dirs()) do
-        table.insert(dirs, dir .. "/icons")
-    end
-    table.insert(dirs, "/usr/share/pixmaps")
-
-    return dirs
-end
 
 local get_pragmatic_base_directories = function()
     local dirs = {}
@@ -98,8 +83,8 @@ local index_theme_cache = {}
 -- @tparam table base_directories Paths used for lookup
 -- @treturn table An instance of the class `icon_theme`
 icon_theme.new = function(icon_theme_name, base_directories)
-    local icon_theme_name = icon_theme_name or beautiful.icon_theme or get_default_icon_theme_name()
-    local base_directories = base_directories or get_pragmatic_base_directories()
+    icon_theme_name = icon_theme_name or beautiful.icon_theme or get_default_icon_theme_name()
+    base_directories = base_directories or get_pragmatic_base_directories()
 
     local self = {}
     self.icon_theme_name = icon_theme_name
@@ -238,10 +223,10 @@ end
 -- @tparam number icon_size Prefereable icon size
 -- @treturn string Absolute path to the icon file, or nil if not found
 function icon_theme:find_icon_path(icon_name, icon_size)
+    icon_size = icon_size or 16
     if not icon_name or icon_name == "" then
         return nil
     end
-    local icon_size = icon_size or 16
 
     local filename = find_icon_path_helper(self, icon_name, icon_size)
     if filename then
diff --git a/lib/menubar/init.lua b/lib/menubar/init.lua
index 36a955e3..53e94eb1 100644
--- a/lib/menubar/init.lua
+++ b/lib/menubar/init.lua
@@ -189,7 +189,7 @@ local function menulist_update(query, scr)
     end
 
     -- Add the applications according to their name and cmdline
-    for i, v in ipairs(menubar.menu_entries) do
+    for _, v in ipairs(menubar.menu_entries) do
         v.focused = false
         if not current_category or v.category == current_category then
             if string.match(v.name, pattern)
@@ -205,7 +205,7 @@ local function menulist_update(query, scr)
     end
 
     -- Now add items from match_inside to shownitems
-    for i, v in ipairs(match_inside) do
+    for _, v in ipairs(match_inside) do
         table.insert(shownitems, v)
     end
 
@@ -315,7 +315,7 @@ function menubar.show(scr)
     local prompt_args = menubar.prompt_args or {}
     prompt_args.prompt = "Run: "
     awful.prompt.run(prompt_args, instance.prompt.widget,
-                function(s) end,            -- exe_callback function set to do nothing
+                function() end,            -- exe_callback function set to do nothing
                 awful.completion.shell,     -- completion_callback
                 awful.util.get_cache_dir() .. "/history_menu",
                 nil,
diff --git a/lib/menubar/utils.lua b/lib/menubar/utils.lua
index 1279f1d9..80edc753 100644
--- a/lib/menubar/utils.lua
+++ b/lib/menubar/utils.lua
@@ -83,7 +83,7 @@ local function get_icon_lookup_path()
         table.insert(paths, 1, glib.get_user_data_dir())
         table.insert(paths, 1, glib.build_filenamev({glib.get_home_dir(),
                                                      '.icons'}))
-        for k,dir in ipairs(paths) do
+        for _,dir in ipairs(paths) do
             local icons_dir = glib.build_filenamev({dir, 'icons'})
             if awful_util.dir_readable(icons_dir) then
                 if icon_theme then
@@ -96,14 +96,14 @@ local function get_icon_lookup_path()
                                 glib.build_filenamev({icons_dir, 'hicolor'}))
             end
         end
-        for i, icon_theme_directory in ipairs(icon_theme_paths) do
-            for j, size in ipairs(all_icon_sizes) do
+        for _, icon_theme_directory in ipairs(icon_theme_paths) do
+            for _, size in ipairs(all_icon_sizes) do
                 add_if_readable(icon_lookup_path,
                                 glib.build_filenamev({icon_theme_directory,
                                                       size, 'apps'}))
             end
         end
-        for k,dir in ipairs(paths)do
+        for _,dir in ipairs(paths)do
             -- lowest priority fallbacks
             add_if_readable(icon_lookup_path,
                             glib.build_filenamev({dir, 'pixmaps'}))
@@ -127,7 +127,7 @@ function utils.lookup_icon_uncached(icon_file)
         -- supported, do not perform a lookup.
         return awful_util.file_readable(icon_file) and icon_file or nil
     else
-        for i, directory in ipairs(get_icon_lookup_path()) do
+        for _, directory in ipairs(get_icon_lookup_path()) do
             if is_format_supported(icon_file) and
                     awful_util.file_readable(directory .. "/" .. icon_file) then
                 return directory .. "/" .. icon_file
@@ -170,6 +170,7 @@ function utils.parse(file)
     for line in io.lines(file) do
         if line:find("^%s*#") then
             -- Skip comments.
+            (function() end)() -- I haven't found a nice way to silence luacheck here
         elseif not desktop_entry and line == "[Desktop Entry]" then
             desktop_entry = true
         else
@@ -260,7 +261,7 @@ end
 -- @treturn int Text width.
 function utils.compute_textbox_width(textbox, s)
     s = s or mouse.screen
-    local w, h = textbox:get_preferred_size(s)
+    local w, _ = textbox:get_preferred_size(s)
     return w
 end
 
diff --git a/spec/awful/util_spec.lua b/spec/awful/util_spec.lua
index 5e39f181..07bb1da1 100644
--- a/spec/awful/util_spec.lua
+++ b/spec/awful/util_spec.lua
@@ -4,7 +4,6 @@
 ---------------------------------------------------------------------------
 
 local util = require("awful.util")
-local say = require("say")
 
 describe("awful.util", function()
     it("table.keys_filter", function()
diff --git a/spec/gears/color_spec.lua b/spec/gears/color_spec.lua
index e7694e34..47b157ca 100644
--- a/spec/gears/color_spec.lua
+++ b/spec/gears/color_spec.lua
@@ -162,7 +162,7 @@ describe("gears.color", function()
 
     describe("create_opaque_pattern", function()
         -- Assertion to check if a pattern is opaque
-        local function opaque(state, arguments)
+        local function opaque(_, arguments)
             assert(arguments.n >= 1, say("assertions.argtolittle", { "opaque", 1, tostring(arguments.n) }))
             local pattern = color.create_opaque_pattern(arguments[1])
             return pattern ~= nil
diff --git a/spec/gears/object_spec.lua b/spec/gears/object_spec.lua
index e63463dc..2f41f0d1 100644
--- a/spec/gears/object_spec.lua
+++ b/spec/gears/object_spec.lua
@@ -54,7 +54,7 @@ describe("gears.object", function()
         obj:weak_connect_signal("signal", cb)
 
         -- Check that the GC doesn't disconnect the signal
-        for i = 1, 10 do
+        for _ = 1, 10 do
             collectgarbage("collect")
         end
 
@@ -149,7 +149,8 @@ describe("gears.object", function()
                 finalized = true
             end
             if _VERSION <= "Lua 5.1" then
-                local userdata = newproxy(true)
+                -- luacheck: globals newproxy
+                userdata = newproxy(true)
                 getmetatable(userdata).__gc = gc
                 getmetatable(userdata).callback = callback
             else
diff --git a/spec/menubar/icon_theme_spec.lua b/spec/menubar/icon_theme_spec.lua
index f02fd3a8..8588d3a2 100644
--- a/spec/menubar/icon_theme_spec.lua
+++ b/spec/menubar/icon_theme_spec.lua
@@ -6,24 +6,24 @@
 -- Hack so that beautiful can be loaded
 _G.awesome = {
     xrdb_get_value = function() end,
-    connect_signal = function(...) end,
-    register_xproperty = function(...) end
+    connect_signal = function() end,
+    register_xproperty = function() end
 }
 -- Additional hacks to load menubar
 _G.screen = {
-    add_signal = function(...) end,
+    add_signal = function() end,
     count = function() return 0 end
 }
 _G.client = {
-    connect_signal = function(...) end,
-    add_signal = function(...) end
+    connect_signal = function() end,
+    add_signal = function() end
 }
 _G.tag = {
-    connect_signal = function(...) end,
-    add_signal = function(...) end
+    connect_signal = function() end,
+    add_signal = function() end
 }
 _G.root = {
-    cursor = function(...) end
+    cursor = function() end
 }
 
 local os = os
diff --git a/spec/wibox/hierarchy_spec.lua b/spec/wibox/hierarchy_spec.lua
index 55d7dc94..92541bc0 100644
--- a/spec/wibox/hierarchy_spec.lua
+++ b/spec/wibox/hierarchy_spec.lua
@@ -7,7 +7,6 @@ local hierarchy = require("wibox.hierarchy")
 
 local Region = require("lgi").cairo.Region
 local matrix = require("gears.matrix")
-local object = require("gears.object")
 local utils = require("wibox.test_utils")
 
 local function make_widget(children)
@@ -18,8 +17,8 @@ local function make_widget(children)
     return result
 end
 
-local function make_child(widget, width, height, matrix)
-    return { _widget = widget, _width = width, _height = height, _matrix = matrix }
+local function make_child(widget, width, height, mat)
+    return { _widget = widget, _width = width, _height = height, _matrix = mat }
 end
 
 describe("wibox.hierarchy", function()
@@ -95,7 +94,7 @@ describe("wibox.hierarchy", function()
             end
         end
         local context = {}
-        local instance = hierarchy.new(context, parent, 15, 20, redraw, layout, extra_arg)
+        local instance = hierarchy.new(context, parent, 15, 20, redraw, layout, extra_arg) -- luacheck: no unused
 
         -- There should be a connection
         parent:emit_signal("widget::redraw_needed")
@@ -140,7 +139,7 @@ describe("wibox.hierarchy", function()
             assert.is.equal(#children, 1)
             hierarchy_intermediate = children[1]
 
-            local children = hierarchy_intermediate:get_children()
+            children = hierarchy_intermediate:get_children()
             assert.is.equal(#children, 1)
             hierarchy_child = children[1]
         end)
diff --git a/spec/wibox/test_utils.lua b/spec/wibox/test_utils.lua
index 08d2b01b..a557df76 100644
--- a/spec/wibox/test_utils.lua
+++ b/spec/wibox/test_utils.lua
@@ -4,7 +4,6 @@
 ---------------------------------------------------------------------------
 
 local object = require("gears.object")
-local cache = require("gears.cache")
 local matrix_equals = require("gears.matrix").equals
 local base = require("wibox.widget.base")
 local say = require("say")
@@ -53,11 +52,11 @@ local function widget_layout(state, arguments)
         fits = false
     else
         for i = 1, #children do
-            local child, expected = children[i], expected[i]
-            if child._widget ~= expected._widget or
-                child._width ~= expected._width or
-                child._height ~= expected._height or
-                not matrix_equals(child._matrix, expected._matrix) then
+            local child, exp = children[i], expected[i]
+            if child._widget ~= exp._widget or
+                child._width ~= exp._width or
+                child._height ~= exp._height or
+                not matrix_equals(child._matrix, exp._matrix) then
                 fits = false
                 break
             end
diff --git a/themes/default/theme.lua b/themes/default/theme.lua
index 9577ad94..ed3c0b94 100644
--- a/themes/default/theme.lua
+++ b/themes/default/theme.lua
@@ -2,7 +2,7 @@
 -- Default awesome theme --
 ---------------------------
 
-theme = {}
+local theme = {}
 
 theme.font          = "sans 8"
 
diff --git a/themes/sky/theme.lua b/themes/sky/theme.lua
index e8fbe7e6..0ce78a8d 100644
--- a/themes/sky/theme.lua
+++ b/themes/sky/theme.lua
@@ -5,7 +5,7 @@
 -- If you want SVGs and extras, get them from garoth.com/awesome/sky-theme
 
 -- BASICS
-theme = {}
+local theme = {}
 theme.font          = "sans 8"
 
 theme.bg_focus      = "#e2eeea"
diff --git a/themes/zenburn/theme.lua b/themes/zenburn/theme.lua
index d6a48863..2b7f56f9 100644
--- a/themes/zenburn/theme.lua
+++ b/themes/zenburn/theme.lua
@@ -7,7 +7,7 @@
 --  * http://awesome.naquadah.org/wiki/Nice_Icons
 
 -- {{{ Main
-theme = {}
+local theme = {}
 theme.wallpaper = "@AWESOME_THEMES_PATH@/zenburn/zenburn-background.png"
 -- }}}