diff --git a/app/models/issue_query.rb b/app/models/issue_query.rb
index ad5e511af..c342dc456 100644
--- a/app/models/issue_query.rb
+++ b/app/models/issue_query.rb
@@ -582,7 +582,7 @@ class IssueQuery < Query
   end
   alias :find_author_id_filter_values :find_assigned_to_id_filter_values
 
-  IssueRelation::TYPES.keys.each do |relation_type|
+  IssueRelation::TYPES.each_key do |relation_type|
     alias_method "sql_for_#{relation_type}_field".to_sym, :sql_for_relations
   end
 
diff --git a/app/models/query.rb b/app/models/query.rb
index f85fd0f65..ed11bbffb 100644
--- a/app/models/query.rb
+++ b/app/models/query.rb
@@ -371,7 +371,7 @@ class Query < ActiveRecord::Base
       self.filters = {}
       add_filters(params[:fields] || params[:f], params[:operators] || params[:op], params[:values] || params[:v])
     else
-      available_filters.keys.each do |field|
+      available_filters.each_key do |field|
         add_short_filter(field, params[field]) if params[field]
       end
     end
@@ -989,7 +989,7 @@ class Query < ActiveRecord::Base
 
   def map_total(total, &block)
     if total.is_a?(Hash)
-      total.keys.each {|k| total[k] = yield total[k]}
+      total.each_key {|k| total[k] = yield total[k]}
     else
       total = yield total
     end
diff --git a/app/models/user_preference.rb b/app/models/user_preference.rb
index efdc41e2d..7373290c5 100644
--- a/app/models/user_preference.rb
+++ b/app/models/user_preference.rb
@@ -122,7 +122,7 @@ class UserPreference < ActiveRecord::Base
   #   preferences.remove_block('news')
   def remove_block(block)
     block = block.to_s.underscore
-    my_page_layout.keys.each do |group|
+    my_page_layout.each_key do |group|
       my_page_layout[group].delete(block)
     end
     my_page_layout
diff --git a/lib/plugins/open_id_authentication/lib/open_id_authentication.rb b/lib/plugins/open_id_authentication/lib/open_id_authentication.rb
index 7afe6fdeb..e31aba1f2 100644
--- a/lib/plugins/open_id_authentication/lib/open_id_authentication.rb
+++ b/lib/plugins/open_id_authentication/lib/open_id_authentication.rb
@@ -61,7 +61,7 @@ module OpenIdAuthentication
       @code
     end
 
-    ERROR_MESSAGES.keys.each { |state| define_method("#{state}?") { @code == state } }
+    ERROR_MESSAGES.each_key { |state| define_method("#{state}?") { @code == state } }
 
     def successful?
       @code == :successful
diff --git a/lib/redmine/helpers/gantt.rb b/lib/redmine/helpers/gantt.rb
index 756dc6e93..ca3b70b6f 100644
--- a/lib/redmine/helpers/gantt.rb
+++ b/lib/redmine/helpers/gantt.rb
@@ -608,7 +608,7 @@ module Redmine
           end
         end
         # Transforms dates into pixels witdh
-        coords.keys.each do |key|
+        coords.each_key do |key|
           coords[key] = (coords[key] * zoom).floor
         end
         coords