diff --git a/app/controllers/projects/wiki_controller.rb b/app/controllers/projects/wiki_controller.rb
index 30a78d38c..fd4fc110e 100644
--- a/app/controllers/projects/wiki_controller.rb
+++ b/app/controllers/projects/wiki_controller.rb
@@ -245,7 +245,7 @@ class Projects::WikiController < Projects::BaseController
           when 'revert'      then "Reverted page #{@name.to_s}"
           when 'revert_wiki' then "Reverted wiki"
         end
-        msg += " (#{params['format']})" if params['format']
+        msg << " (#{params['format']})" if params['format']
       end
       msg = 'Unhandled action' if !msg || msg.empty?
       { :message => msg }
diff --git a/app/helpers/diff_helper.rb b/app/helpers/diff_helper.rb
index 6974ca1ad..cfa2a0459 100644
--- a/app/helpers/diff_helper.rb
+++ b/app/helpers/diff_helper.rb
@@ -37,12 +37,12 @@ module DiffHelper
            end
     prepare(args.merge({:filepath => filepath, :comments => comments, :in_discussion => in_discussion}))
 
-    res = "<table class='diff inline' cellspacing='0' cellpadding='0' ng-non-bindable>"
-    res += "<tbody>"
-    res += renderer diff_display.data #diff_display.render(Git::Diff::InlineCallback.new comments, path)
-    res += tr_line_comments(comments) if in_discussion
-    res += "</tbody>"
-    res += "</table>"
+    res = '<table class="diff inline" cellspacing="0" cellpadding="0" ng-non-bindable>'
+    res << '<tbody>'
+    res << renderer(diff_display.data) #diff_display.render(Git::Diff::InlineCallback.new comments, path)
+    res << tr_line_comments(comments) if in_discussion
+    res << '</tbody>'
+    res << '</table>'
     res.html_safe
   end
 
@@ -214,11 +214,11 @@ module DiffHelper
     res = '<span class="diff-content">'
     if line.inline_changes?
       prefix, changed, postfix = line.segments.map{|segment| escape(segment) }
-      res += "#{prefix}<span class='idiff'>#{changed}</span>#{postfix}"
+      res << "#{prefix}<span class='idiff'>#{changed}</span>#{postfix}"
     else
-      res += escape(line)
+      res << escape(line)
     end
-    res += '</span>'
+    res << '</span>'
 
     res
   end
diff --git a/app/helpers/git_helper.rb b/app/helpers/git_helper.rb
index 559deeeb3..c1f71742d 100644
--- a/app/helpers/git_helper.rb
+++ b/app/helpers/git_helper.rb
@@ -33,15 +33,15 @@ module GitHelper
       parts = @path.split("/")
 
       current_path = parts.first
-      res += parts.length == 1 ? parts.first : link_to(parts.first, tree_path(@project, @treeish, current_path)) + " / "
+      res << (parts.length == 1 ? parts.first : link_to(parts.first, tree_path(@project, @treeish, current_path)) + " / ")
 
       parts[1..-2].each do |part|
         current_path = File.join([current_path, part].compact)
-        res += link_to(part, tree_path(@project, @treeish, current_path))
-        res += " / "
+        res << link_to(part, tree_path(@project, @treeish, current_path))
+        res << " / "
       end
 
-      res += parts.last if parts.length > 1
+      res << parts.last if parts.length > 1
     else
       res = "#{link_to @project.name, tree_path(@project)} /"
     end
@@ -51,7 +51,7 @@ module GitHelper
 
   def render_line_numbers(n)
     res = ""
-    1.upto(n) {|i| res += "<span id='L#{i}'><a href='#L#{i}'>#{i}</a></span><br/>" }
+    1.upto(n){ |i| res << "<span id='L#{i}'><a href='#L#{i}'>#{i}</a></span><br/>" }
 
     res.html_safe
   end