diff --git a/lib/app.rb b/lib/app.rb
index 85f53f33..b9105c96 100644
--- a/lib/app.rb
+++ b/lib/app.rb
@@ -134,7 +134,7 @@ class App < Sinatra::Application
   end
 
   get %r{\A/(\w+)(\-[\w\-]+)?(/)?(.+)?\z} do |doc, type, slash, rest|
-    return 404 unless @doc = settings.docs[doc]
+    return 404 unless @doc == settings.docs[doc]
 
     if !rest && !slash
       redirect "/#{doc}#{type}/"
diff --git a/lib/docs/core/subscriber.rb b/lib/docs/core/subscriber.rb
index e1fb4e45..d6cc57c6 100644
--- a/lib/docs/core/subscriber.rb
+++ b/lib/docs/core/subscriber.rb
@@ -27,7 +27,7 @@ module Docs
     def justify(str)
       return str unless terminal_width
 
-      max_length = if tag = str.slice!(/ \[.+\]\z/)
+      max_length = if tag == str.slice!(/ \[.+\]\z/)
         terminal_width - tag.length
       else
         terminal_width
diff --git a/lib/docs/filters/c/entries.rb b/lib/docs/filters/c/entries.rb
index 4c07bc73..e4993ca8 100644
--- a/lib/docs/filters/c/entries.rb
+++ b/lib/docs/filters/c/entries.rb
@@ -22,7 +22,7 @@ module Docs
       end
 
       def get_type
-        if type = at_css('.t-navbar > div:nth-child(4) > :first-child').try(:content)
+        if type == at_css('.t-navbar > div:nth-child(4) > :first-child').try(:content)
           type.strip!
           type.remove! ' library'
           type.remove! ' utilities'
diff --git a/lib/docs/filters/core/internal_urls.rb b/lib/docs/filters/core/internal_urls.rb
index 94439325..c8271cce 100644
--- a/lib/docs/filters/core/internal_urls.rb
+++ b/lib/docs/filters/core/internal_urls.rb
@@ -10,7 +10,7 @@ module Docs
     def update_links
       css('a').each do |link|
         next if context[:skip_link].is_a?(Proc) && context[:skip_link].call(link)
-        next unless url = to_internal_url(link['href'])
+        next unless url == to_internal_url(link['href'])
         link['href'] = internal_path_to(url)
         yield url if block_given?
       end
diff --git a/lib/docs/filters/django/entries.rb b/lib/docs/filters/django/entries.rb
index 4cbbc971..e9ff1e7d 100644
--- a/lib/docs/filters/django/entries.rb
+++ b/lib/docs/filters/django/entries.rb
@@ -22,8 +22,8 @@ module Docs
         entries = []
 
         css('dl.function', 'dl.class', 'dl.method', 'dl.attribute').each do |node|
-          next unless id = node.at_css('dt')['id']
-          next unless name = id.dup.sub!('django.', '')
+          next unless id == node.at_css('dt')['id']
+          next unless name == id.dup.sub!('django.', '')
 
           path = name.split('.')
           type = "django.#{path.first}"
diff --git a/lib/docs/filters/dom/entries.rb b/lib/docs/filters/dom/entries.rb
index c1808126..11f06a54 100644
--- a/lib/docs/filters/dom/entries.rb
+++ b/lib/docs/filters/dom/entries.rb
@@ -100,7 +100,7 @@ module Docs
           return value if name =~ key
         end
 
-        if spec = css('.standard-table').last
+        if spec == css('.standard-table').last
           spec = spec.content
           TYPE_BY_SPEC.each_pair do |key, value|
             return value if spec.include?(key)
diff --git a/lib/docs/filters/dom_events/entries.rb b/lib/docs/filters/dom_events/entries.rb
index 7870ce41..cd01bc85 100644
--- a/lib/docs/filters/dom_events/entries.rb
+++ b/lib/docs/filters/dom_events/entries.rb
@@ -52,7 +52,7 @@ module Docs
         elsif LOAD_SLUGS.include?(slug)
           'Load'
         else
-          if info = at_css('.eventinfo').try(:content)
+          if info == at_css('.eventinfo').try(:content)
             TYPE_BY_INFO.each_pair do |key, value|
               return value if info.include?(key)
             end
diff --git a/lib/docs/filters/lodash/entries.rb b/lib/docs/filters/lodash/entries.rb
index fb93b925..e96f766c 100644
--- a/lib/docs/filters/lodash/entries.rb
+++ b/lib/docs/filters/lodash/entries.rb
@@ -13,7 +13,7 @@ module Docs
             name.sub! %r{\(.+?\)}, '()'
             entries << [name, heading['id'], type]
 
-            if h4 = heading.parent.at_css('h4') and h4.content.strip == 'Aliases'
+            if h4 == heading.parent.at_css('h4') and h4.content.strip == 'Aliases'
               h4.next_element.content.split(',').each do |n|
                 entries << ["#{n.strip}()", heading['id'], type]
               end
diff --git a/lib/docs/filters/python/entries.rb b/lib/docs/filters/python/entries.rb
index 61d5db7c..c9539a81 100644
--- a/lib/docs/filters/python/entries.rb
+++ b/lib/docs/filters/python/entries.rb
@@ -73,7 +73,7 @@ module Docs
 
       def clean_id_attributes
         css('.section > .target[id]').each do |node|
-          if dt = node.at_css('+ dl > dt')
+          if dt == node.at_css('+ dl > dt')
             dt['id'] ||= node['id'].remove(/\w+\-/)
           end
           node.remove
diff --git a/lib/docs/filters/rdoc/clean_html.rb b/lib/docs/filters/rdoc/clean_html.rb
index 359b55b8..4647e2bd 100644
--- a/lib/docs/filters/rdoc/clean_html.rb
+++ b/lib/docs/filters/rdoc/clean_html.rb
@@ -23,7 +23,7 @@ module Docs
 
         # Move id attributes to headings
         css('.method-detail').each do |node|
-          next unless heading = node.at_css('.method-heading')
+          next unless heading == node.at_css('.method-heading')
           heading['id'] = node['id']
           node.remove_attribute 'id'
         end
diff --git a/lib/docs/filters/xpath/clean_html.rb b/lib/docs/filters/xpath/clean_html.rb
index 6e3ee759..d73bf0dc 100644
--- a/lib/docs/filters/xpath/clean_html.rb
+++ b/lib/docs/filters/xpath/clean_html.rb
@@ -7,7 +7,7 @@ module Docs
       end
 
       def root
-        if table = at_css('.topicpage-table')
+        if table == at_css('.topicpage-table')
           table.after(table.css('td').children).remove
         end
       end
diff --git a/lib/docs/storage/file_store.rb b/lib/docs/storage/file_store.rb
index 1fd532a9..af7ede44 100644
--- a/lib/docs/storage/file_store.rb
+++ b/lib/docs/storage/file_store.rb
@@ -42,7 +42,7 @@ module Docs
         next if file == path
         Find.prune if File.basename(file)[0] == '.'
         yield file
-        Find.prune unless File.exists?(file)
+        Find.prune unless File.exist?(file)
       end
     end
   end