101 files changed, 366 insertions, 364 deletions

diff --git a/.rubocop.yml b/.rubocop.yml
index a673e6ba83..c6c8d8ca00 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -208,3 +208,6 @@ Performance/EndWith:
 
 Performance/RegexpMatch:
   Enabled: true
+
+Performance/UnfreezeString:
+  Enabled: true
diff --git a/actioncable/lib/action_cable/channel/base.rb b/actioncable/lib/action_cable/channel/base.rb
index c5ad749bfe..70c93ec0f3 100644
--- a/actioncable/lib/action_cable/channel/base.rb
+++ b/actioncable/lib/action_cable/channel/base.rb
@@ -270,7 +270,7 @@ module ActionCable
         end
 
         def action_signature(action, data)
-          "#{self.class.name}##{action}".dup.tap do |signature|
+          (+"#{self.class.name}##{action}").tap do |signature|
             if (arguments = data.except("action")).any?
               signature << "(#{arguments.inspect})"
             end
diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
index 7898996c30..7a1a505398 100644
--- a/actionmailer/test/base_test.rb
+++ b/actionmailer/test/base_test.rb
@@ -122,7 +122,7 @@ class BaseTest < ActiveSupport::TestCase
     email = BaseMailer.attachment_with_hash
     assert_equal(1, email.attachments.length)
     assert_equal("invoice.jpg", email.attachments[0].filename)
-    expected = "\312\213\254\232)b".dup
+    expected = +"\312\213\254\232)b"
     expected.force_encoding(Encoding::BINARY)
     assert_equal expected, email.attachments["invoice.jpg"].decoded
   end
@@ -131,7 +131,7 @@ class BaseTest < ActiveSupport::TestCase
     email = BaseMailer.attachment_with_hash_default_encoding
     assert_equal(1, email.attachments.length)
     assert_equal("invoice.jpg", email.attachments[0].filename)
-    expected = "\312\213\254\232)b".dup
+    expected = +"\312\213\254\232)b"
     expected.force_encoding(Encoding::BINARY)
     assert_equal expected, email.attachments["invoice.jpg"].decoded
   end
diff --git a/actionpack/lib/action_controller/log_subscriber.rb b/actionpack/lib/action_controller/log_subscriber.rb
index 14f41eb55f..203653354a 100644
--- a/actionpack/lib/action_controller/log_subscriber.rb
+++ b/actionpack/lib/action_controller/log_subscriber.rb
@@ -26,7 +26,7 @@ module ActionController
           exception_class_name = payload[:exception].first
           status = ActionDispatch::ExceptionWrapper.status_code_for_exception(exception_class_name)
         end
-        message = "Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in #{event.duration.round}ms".dup
+        message = +"Completed #{status} #{Rack::Utils::HTTP_STATUS_CODES[status]} in #{event.duration.round}ms"
         message << " (#{additions.join(" | ".freeze)})" unless additions.empty?
         message << "\n\n" if defined?(Rails.env) && Rails.env.development?
 
diff --git a/actionpack/lib/action_controller/metal/http_authentication.rb b/actionpack/lib/action_controller/metal/http_authentication.rb
index a871ccd533..5794e0fb97 100644
--- a/actionpack/lib/action_controller/metal/http_authentication.rb
+++ b/actionpack/lib/action_controller/metal/http_authentication.rb
@@ -474,7 +474,7 @@ module ActionController
 
       # This removes the <tt>"</tt> characters wrapping the value.
       def rewrite_param_values(array_params)
-        array_params.each { |param| (param[1] || "".dup).gsub! %r/^"|"$/, "" }
+        array_params.each { |param| (param[1] || +"").gsub! %r/^"|"$/, "" }
       end
 
       # This method takes an authorization body and splits up the key-value
diff --git a/actionpack/lib/action_controller/metal/live.rb b/actionpack/lib/action_controller/metal/live.rb
index b1c2391afe..5680ef08a1 100644
--- a/actionpack/lib/action_controller/metal/live.rb
+++ b/actionpack/lib/action_controller/metal/live.rb
@@ -297,7 +297,7 @@ module ActionController
       return unless logger
 
       logger.fatal do
-        message = "\n#{exception.class} (#{exception.message}):\n".dup
+        message = +"\n#{exception.class} (#{exception.message}):\n"
         message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
         message << "  " << exception.backtrace.join("\n  ")
         "#{message}\n\n"
diff --git a/actionpack/lib/action_controller/metal/rendering.rb b/actionpack/lib/action_controller/metal/rendering.rb
index 6d181e6456..7d0a944381 100644
--- a/actionpack/lib/action_controller/metal/rendering.rb
+++ b/actionpack/lib/action_controller/metal/rendering.rb
@@ -40,7 +40,7 @@ module ActionController
     def render_to_string(*)
       result = super
       if result.respond_to?(:each)
-        string = "".dup
+        string = +""
         result.each { |r| string << r }
         string
       else
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 885dc0ecba..f07be831d4 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -105,7 +105,7 @@ module ActionDispatch # :nodoc:
 
       def body
         @str_body ||= begin
-          buf = "".dup
+          buf = +""
           each { |chunk| buf << chunk }
           buf
         end
diff --git a/actionpack/lib/action_dispatch/http/url.rb b/actionpack/lib/action_dispatch/http/url.rb
index 35ba44005a..db6d8188d3 100644
--- a/actionpack/lib/action_dispatch/http/url.rb
+++ b/actionpack/lib/action_dispatch/http/url.rb
@@ -157,7 +157,7 @@ module ActionDispatch
           subdomain  = options.fetch :subdomain, true
           domain     = options[:domain]
 
-          host = "".dup
+          host = +""
           if subdomain == true
             return _host if domain.nil?
 
diff --git a/actionpack/lib/action_dispatch/journey/formatter.rb b/actionpack/lib/action_dispatch/journey/formatter.rb
index 0f04839d9b..52396ec901 100644
--- a/actionpack/lib/action_dispatch/journey/formatter.rb
+++ b/actionpack/lib/action_dispatch/journey/formatter.rb
@@ -50,7 +50,7 @@ module ActionDispatch
         unmatched_keys = (missing_keys || []) & constraints.keys
         missing_keys = (missing_keys || []) - unmatched_keys
 
-        message = "No route matches #{Hash[constraints.sort_by { |k, v| k.to_s }].inspect}".dup
+        message = +"No route matches #{Hash[constraints.sort_by { |k, v| k.to_s }].inspect}"
         message << ", missing required keys: #{missing_keys.sort.inspect}" if missing_keys && !missing_keys.empty?
         message << ", possible unmatched constraints: #{unmatched_keys.sort.inspect}" if unmatched_keys && !unmatched_keys.empty?
 
diff --git a/actionpack/lib/action_dispatch/journey/router/utils.rb b/actionpack/lib/action_dispatch/journey/router/utils.rb
index df3f79a407..3bbb187f5c 100644
--- a/actionpack/lib/action_dispatch/journey/router/utils.rb
+++ b/actionpack/lib/action_dispatch/journey/router/utils.rb
@@ -17,11 +17,11 @@ module ActionDispatch
         def self.normalize_path(path)
           path ||= ""
           encoding = path.encoding
-          path = "/#{path}".dup
+          path = +"/#{path}"
           path.squeeze!("/".freeze)
           path.sub!(%r{/+\Z}, "".freeze)
           path.gsub!(/(%[a-f0-9]{2})/) { $1.upcase }
-          path = "/".dup if path == "".freeze
+          path = +"/" if path == "".freeze
           path.force_encoding(encoding)
           path
         end
@@ -32,7 +32,7 @@ module ActionDispatch
           ENCODE   = "%%%02X".freeze
           US_ASCII = Encoding::US_ASCII
           UTF_8    = Encoding::UTF_8
-          EMPTY    = "".dup.force_encoding(US_ASCII).freeze
+          EMPTY    = (+"").force_encoding(US_ASCII).freeze
           DEC2HEX  = (0..255).to_a.map { |i| ENCODE % i }.map { |s| s.force_encoding(US_ASCII) }
 
           ALPHA = "a-zA-Z".freeze
diff --git a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
index 077a83b112..5f5fdbc66a 100644
--- a/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
+++ b/actionpack/lib/action_dispatch/middleware/debug_exceptions.rb
@@ -23,7 +23,7 @@ module ActionDispatch
         if clean_params.empty?
           "None"
         else
-          PP.pp(clean_params, "".dup, 200)
+          PP.pp(clean_params, +"", 200)
         end
       end
 
diff --git a/actionpack/lib/action_dispatch/middleware/debug_locks.rb b/actionpack/lib/action_dispatch/middleware/debug_locks.rb
index 03760438f7..d39377f174 100644
--- a/actionpack/lib/action_dispatch/middleware/debug_locks.rb
+++ b/actionpack/lib/action_dispatch/middleware/debug_locks.rb
@@ -63,19 +63,19 @@ module ActionDispatch
 
         str = threads.map do |thread, info|
           if info[:exclusive]
-            lock_state = "Exclusive".dup
+            lock_state = +"Exclusive"
           elsif info[:sharing] > 0
-            lock_state = "Sharing".dup
+            lock_state = +"Sharing"
             lock_state << " x#{info[:sharing]}" if info[:sharing] > 1
           else
-            lock_state = "No lock".dup
+            lock_state = +"No lock"
           end
 
           if info[:waiting]
             lock_state << " (yielded share)"
           end
 
-          msg = "Thread #{info[:index]} [0x#{thread.__id__.to_s(16)} #{thread.status || 'dead'}]  #{lock_state}\n".dup
+          msg = +"Thread #{info[:index]} [0x#{thread.__id__.to_s(16)} #{thread.status || 'dead'}]  #{lock_state}\n"
 
           if info[:sleeper]
             msg << "  Waiting in #{info[:sleeper]}"
diff --git a/actionpack/lib/action_dispatch/middleware/ssl.rb b/actionpack/lib/action_dispatch/middleware/ssl.rb
index 190e54223e..9c9ccfa16f 100644
--- a/actionpack/lib/action_dispatch/middleware/ssl.rb
+++ b/actionpack/lib/action_dispatch/middleware/ssl.rb
@@ -102,7 +102,7 @@ module ActionDispatch
 
       # https://tools.ietf.org/html/rfc6797#section-6.1
       def build_hsts_header(hsts)
-        value = "max-age=#{hsts[:expires].to_i}".dup
+        value = +"max-age=#{hsts[:expires].to_i}"
         value << "; includeSubDomains" if hsts[:subdomains]
         value << "; preload" if hsts[:preload]
         value
@@ -141,7 +141,7 @@ module ActionDispatch
         host = @redirect[:host] || request.host
         port = @redirect[:port] || request.port
 
-        location = "https://#{host}".dup
+        location = +"https://#{host}"
         location << ":#{port}" if port != 80 && port != 443
         location << request.fullpath
         location
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 07e3be4db8..3f7cf0950d 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -308,7 +308,7 @@ module ActionDispatch
           def check_controller_and_action(path_params, controller, action)
             hash = check_part(:controller, controller, path_params, {}) do |part|
               translate_controller(part) {
-                message = "'#{part}' is not a supported controller name. This can lead to potential routing problems.".dup
+                message = +"'#{part}' is not a supported controller name. This can lead to potential routing problems."
                 message << " See https://guides.rubyonrails.org/routing.html#specifying-a-controller-to-use"
 
                 raise ArgumentError, message
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 07d3a41173..acce8a7ef3 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -245,7 +245,7 @@ module ActionDispatch
                   missing_keys << missing_key
                 }
                 constraints = Hash[@route.requirements.merge(params).sort_by { |k, v| k.to_s }]
-                message = "No route matches #{constraints.inspect}".dup
+                message = +"No route matches #{constraints.inspect}"
                 message << ", missing required keys: #{missing_keys.sort.inspect}"
 
                 raise ActionController::UrlGenerationError, message
diff --git a/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
index d2685e0452..884fb51d18 100644
--- a/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
+++ b/actionpack/lib/action_dispatch/system_testing/test_helpers/screenshot_helper.rb
@@ -65,7 +65,7 @@ module ActionDispatch
           end
 
           def display_image
-            message = "[Screenshot]: #{image_path}\n".dup
+            message = +"[Screenshot]: #{image_path}\n"
 
             case output_type
             when "artifact"
diff --git a/actionpack/lib/action_dispatch/testing/assertions/response.rb b/actionpack/lib/action_dispatch/testing/assertions/response.rb
index 98b1965d22..8595ea03cf 100644
--- a/actionpack/lib/action_dispatch/testing/assertions/response.rb
+++ b/actionpack/lib/action_dispatch/testing/assertions/response.rb
@@ -79,9 +79,8 @@ module ActionDispatch
         end
 
         def generate_response_message(expected, actual = @response.response_code)
-          "Expected response to be a <#{code_with_name(expected)}>,"\
-          " but was a <#{code_with_name(actual)}>"
-            .dup.concat(location_if_redirected).concat(response_body_if_short)
+          (+"Expected response to be a <#{code_with_name(expected)}>,"\
+          " but was a <#{code_with_name(actual)}>").concat(location_if_redirected).concat(response_body_if_short)
         end
 
         def response_body_if_short
diff --git a/actionpack/test/controller/http_token_authentication_test.rb b/actionpack/test/controller/http_token_authentication_test.rb
index 672aa1351c..103123f98c 100644
--- a/actionpack/test/controller/http_token_authentication_test.rb
+++ b/actionpack/test/controller/http_token_authentication_test.rb
@@ -150,7 +150,7 @@ class HttpTokenAuthenticationTest < ActionController::TestCase
   end
 
   test "token_and_options returns empty string with empty token" do
-    token = "".dup
+    token = +""
     actual = ActionController::HttpAuthentication::Token.token_and_options(sample_request(token)).first
     expected = token
     assert_equal(expected, actual)
diff --git a/actionpack/test/controller/new_base/bare_metal_test.rb b/actionpack/test/controller/new_base/bare_metal_test.rb
index b049022a06..7572d514fb 100644
--- a/actionpack/test/controller/new_base/bare_metal_test.rb
+++ b/actionpack/test/controller/new_base/bare_metal_test.rb
@@ -13,7 +13,7 @@ module BareMetalTest
     test "response body is a Rack-compatible response" do
       status, headers, body = BareController.action(:index).call(Rack::MockRequest.env_for("/"))
       assert_equal 200, status
-      string = "".dup
+      string = +""
 
       body.each do |part|
         assert part.is_a?(String), "Each part of the body must be a String"
diff --git a/actionpack/test/controller/routing_test.rb b/actionpack/test/controller/routing_test.rb
index a7033b2d30..a2a811f090 100644
--- a/actionpack/test/controller/routing_test.rb
+++ b/actionpack/test/controller/routing_test.rb
@@ -674,7 +674,7 @@ class LegacyRouteSetTests < ActiveSupport::TestCase
     assert_equal "/page/foo", url_for(rs, controller: "content", action: "show_page", id: "foo")
     assert_equal({ controller: "content", action: "show_page", id: "foo" }, rs.recognize_path("/page/foo"))
 
-    token = "\321\202\320\265\320\272\321\201\321\202".dup # 'text' in Russian
+    token = +"\321\202\320\265\320\272\321\201\321\202" # 'text' in Russian
     token.force_encoding(Encoding::BINARY)
     escaped_token = CGI.escape(token)
 
diff --git a/actionpack/test/dispatch/debug_exceptions_test.rb b/actionpack/test/dispatch/debug_exceptions_test.rb
index 44b79c0e5d..37399cfd07 100644
--- a/actionpack/test/dispatch/debug_exceptions_test.rb
+++ b/actionpack/test/dispatch/debug_exceptions_test.rb
@@ -368,7 +368,7 @@ class DebugExceptionsTest < ActionDispatch::IntegrationTest
     })
     assert_response 500
 
-    assert_includes(body, CGI.escapeHTML(PP.pp(params, "".dup, 200)))
+    assert_includes(body, CGI.escapeHTML(PP.pp(params, +"", 200)))
   end
 
   test "sets the HTTP charset parameter" do
diff --git a/actionpack/test/dispatch/prefix_generation_test.rb b/actionpack/test/dispatch/prefix_generation_test.rb
index 85ea04356a..7a7a201b11 100644
--- a/actionpack/test/dispatch/prefix_generation_test.rb
+++ b/actionpack/test/dispatch/prefix_generation_test.rb
@@ -13,7 +13,7 @@ module TestGenerationPrefix
     end
 
     def self.model_name
-      klass = "Post".dup
+      klass = +"Post"
       def klass.name; self end
 
       ActiveModel::Name.new(klass)
diff --git a/actionpack/test/dispatch/static_test.rb b/actionpack/test/dispatch/static_test.rb
index 6b69cd9999..d44aa00122 100644
--- a/actionpack/test/dispatch/static_test.rb
+++ b/actionpack/test/dispatch/static_test.rb
@@ -31,7 +31,7 @@ module StaticTests
   end
 
   def test_handles_urls_with_ascii_8bit
-    assert_equal "Hello, World!", get("/doorkeeper%E3E4".dup.force_encoding("ASCII-8BIT")).body
+    assert_equal "Hello, World!", get((+"/doorkeeper%E3E4").force_encoding("ASCII-8BIT")).body
   end
 
   def test_handles_urls_with_ascii_8bit_on_win_31j
@@ -39,7 +39,7 @@ module StaticTests
       Encoding.default_internal = "Windows-31J"
       Encoding.default_external = "Windows-31J"
     end
-    assert_equal "Hello, World!", get("/doorkeeper%E3E4".dup.force_encoding("ASCII-8BIT")).body
+    assert_equal "Hello, World!", get((+"/doorkeeper%E3E4").force_encoding("ASCII-8BIT")).body
   end
 
   def test_handles_urls_with_null_byte
diff --git a/actionpack/test/journey/router/utils_test.rb b/actionpack/test/journey/router/utils_test.rb
index 2d09098f11..472f1bf35e 100644
--- a/actionpack/test/journey/router/utils_test.rb
+++ b/actionpack/test/journey/router/utils_test.rb
@@ -23,7 +23,7 @@ module ActionDispatch
         end
 
         def test_uri_unescape_with_utf8_string
-          assert_equal "Šašinková", Utils.unescape_uri("%C5%A0a%C5%A1inkov%C3%A1".dup.force_encoding(Encoding::US_ASCII))
+          assert_equal "Šašinková", Utils.unescape_uri((+"%C5%A0a%C5%A1inkov%C3%A1").force_encoding(Encoding::US_ASCII))
         end
 
         def test_normalize_path_not_greedy
diff --git a/actionview/lib/action_view/helpers/date_helper.rb b/actionview/lib/action_view/helpers/date_helper.rb
index 4de4fafde0..ecdad14f90 100644
--- a/actionview/lib/action_view/helpers/date_helper.rb
+++ b/actionview/lib/action_view/helpers/date_helper.rb
@@ -1053,7 +1053,7 @@ module ActionView
           select_options[:disabled] = "disabled" if @options[:disabled]
           select_options[:class] = css_class_attribute(type, select_options[:class], @options[:with_css_classes]) if @options[:with_css_classes]
 
-          select_html = "\n".dup
+          select_html = +"\n"
           select_html << content_tag("option".freeze, "", value: "") + "\n" if @options[:include_blank]
           select_html << prompt_option_tag(type, @options[:prompt]) + "\n" if @options[:prompt]
           select_html << select_options_as_html
@@ -1135,7 +1135,7 @@ module ActionView
         # Given an ordering of datetime components, create the selection HTML
         # and join them with their appropriate separators.
         def build_selects_from_types(order)
-          select = "".dup
+          select = +""
           first_visible = order.find { |type| !@options[:"discard_#{type}"] }
           order.reverse_each do |type|
             separator = separator(type) unless type == first_visible # don't add before first visible field
diff --git a/actionview/lib/action_view/helpers/javascript_helper.rb b/actionview/lib/action_view/helpers/javascript_helper.rb
index f80d0bd4ed..ac6ec5a86c 100644
--- a/actionview/lib/action_view/helpers/javascript_helper.rb
+++ b/actionview/lib/action_view/helpers/javascript_helper.rb
@@ -15,8 +15,8 @@ module ActionView
         "'"     => "\\'"
       }
 
-      JS_ESCAPE_MAP["\342\200\250".dup.force_encoding(Encoding::UTF_8).encode!] = "&#x2028;"
-      JS_ESCAPE_MAP["\342\200\251".dup.force_encoding(Encoding::UTF_8).encode!] = "&#x2029;"
+      JS_ESCAPE_MAP[(+"\342\200\250").force_encoding(Encoding::UTF_8).encode!] = "&#x2028;"
+      JS_ESCAPE_MAP[(+"\342\200\251").force_encoding(Encoding::UTF_8).encode!] = "&#x2029;"
 
       # Escapes carriage returns and single and double quotes for JavaScript segments.
       #
diff --git a/actionview/lib/action_view/helpers/tag_helper.rb b/actionview/lib/action_view/helpers/tag_helper.rb
index d12989ea64..a93d7faa32 100644
--- a/actionview/lib/action_view/helpers/tag_helper.rb
+++ b/actionview/lib/action_view/helpers/tag_helper.rb
@@ -58,7 +58,7 @@ module ActionView
 
         def tag_options(options, escape = true)
           return if options.blank?
-          output = "".dup
+          output = +""
           sep    = " "
           options.each_pair do |key, value|
             if TAG_PREFIXES.include?(key) && value.is_a?(Hash)
diff --git a/actionview/lib/action_view/helpers/translation_helper.rb b/actionview/lib/action_view/helpers/translation_helper.rb
index ba82dcab3e..ae1c93e12f 100644
--- a/actionview/lib/action_view/helpers/translation_helper.rb
+++ b/actionview/lib/action_view/helpers/translation_helper.rb
@@ -98,7 +98,7 @@ module ActionView
           raise e if raise_error
 
           keys = I18n.normalize_keys(e.locale, e.key, e.options[:scope])
-          title = "translation missing: #{keys.join('.')}".dup
+          title = +"translation missing: #{keys.join('.')}"
 
           interpolations = options.except(:default, :scope)
           if interpolations.any?
diff --git a/actionview/lib/action_view/log_subscriber.rb b/actionview/lib/action_view/log_subscriber.rb
index d4ac77e10f..db07b9d7fb 100644
--- a/actionview/lib/action_view/log_subscriber.rb
+++ b/actionview/lib/action_view/log_subscriber.rb
@@ -16,7 +16,7 @@ module ActionView
 
     def render_template(event)
       info do
-        message = "  Rendered #{from_rails_root(event.payload[:identifier])}".dup
+        message = +"  Rendered #{from_rails_root(event.payload[:identifier])}"
         message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
         message << " (#{event.duration.round(1)}ms)"
       end
@@ -24,7 +24,7 @@ module ActionView
 
     def render_partial(event)
       info do
-        message = "  Rendered #{from_rails_root(event.payload[:identifier])}".dup
+        message = +"  Rendered #{from_rails_root(event.payload[:identifier])}"
         message << " within #{from_rails_root(event.payload[:layout])}" if event.payload[:layout]
         message << " (#{event.duration.round(1)}ms)"
         message << " #{cache_message(event.payload)}" unless event.payload[:cache_hit].nil?
@@ -85,7 +85,7 @@ module ActionView
 
     def log_rendering_start(payload)
       info do
-        message = "  Rendering #{from_rails_root(payload[:identifier])}".dup
+        message = +"  Rendering #{from_rails_root(payload[:identifier])}"
         message << " within #{from_rails_root(payload[:layout])}" if payload[:layout]
         message
       end
diff --git a/actionview/lib/action_view/renderer/streaming_template_renderer.rb b/actionview/lib/action_view/renderer/streaming_template_renderer.rb
index 276a28ce07..bb9db21e32 100644
--- a/actionview/lib/action_view/renderer/streaming_template_renderer.rb
+++ b/actionview/lib/action_view/renderer/streaming_template_renderer.rb
@@ -33,7 +33,7 @@ module ActionView
           logger = ActionView::Base.logger
           return unless logger
 
-          message = "\n#{exception.class} (#{exception.message}):\n".dup
+          message = +"\n#{exception.class} (#{exception.message}):\n"
           message << exception.annoted_source_code.to_s if exception.respond_to?(:annoted_source_code)
           message << "  " << exception.backtrace.join("\n  ")
           logger.fatal("#{message}\n\n")
diff --git a/actionview/lib/action_view/template.rb b/actionview/lib/action_view/template.rb
index ee1cd61f12..18a5dae270 100644
--- a/actionview/lib/action_view/template.rb
+++ b/actionview/lib/action_view/template.rb
@@ -286,7 +286,7 @@ module ActionView
 
         # Make sure that the resulting String to be eval'd is in the
         # encoding of the code
-        source = <<-end_src.dup
+        source = +<<-end_src
           def #{method_name}(local_assigns, output_buffer)
             _old_virtual_path, @virtual_path = @virtual_path, #{@virtual_path.inspect};_old_output_buffer = @output_buffer;#{locals_code};#{code}
           ensure
@@ -335,12 +335,12 @@ module ActionView
         locals = locals.grep(/\A@?(?![A-Z0-9])(?:[[:alnum:]_]|[^\0-\177])+\z/)
 
         # Assign for the same variable is to suppress unused variable warning
-        locals.each_with_object("".dup) { |key, code| code << "#{key} = local_assigns[:#{key}]; #{key} = #{key};" }
+        locals.each_with_object(+"") { |key, code| code << "#{key} = local_assigns[:#{key}]; #{key} = #{key};" }
       end
 
       def method_name
         @method_name ||= begin
-          m = "_#{identifier_method_name}__#{@identifier.hash}_#{__id__}".dup
+          m = +"_#{identifier_method_name}__#{@identifier.hash}_#{__id__}"
           m.tr!("-".freeze, "_".freeze)
           m
         end
diff --git a/actionview/lib/action_view/template/resolver.rb b/actionview/lib/action_view/template/resolver.rb
index db3cff71df..5027303e86 100644
--- a/actionview/lib/action_view/template/resolver.rb
+++ b/actionview/lib/action_view/template/resolver.rb
@@ -16,7 +16,7 @@ module ActionView
       alias_method :partial?, :partial
 
       def self.build(name, prefix, partial)
-        virtual = "".dup
+        virtual = +""
         virtual << "#{prefix}/" unless prefix.empty?
         virtual << (partial ? "_#{name}" : name)
         new name, prefix, partial, virtual
diff --git a/actionview/lib/action_view/test_case.rb b/actionview/lib/action_view/test_case.rb
index e1cbae5845..e14f7aaec7 100644
--- a/actionview/lib/action_view/test_case.rb
+++ b/actionview/lib/action_view/test_case.rb
@@ -107,7 +107,7 @@ module ActionView
         # empty string ensures buffer has UTF-8 encoding as
         # new without arguments returns ASCII-8BIT encoded buffer like String#new
         @output_buffer = ActiveSupport::SafeBuffer.new ""
-        @rendered = "".dup
+        @rendered = +""
 
         make_test_case_available_to_view!
         say_no_to_protect_against_forgery!
diff --git a/actionview/lib/action_view/testing/resolvers.rb b/actionview/lib/action_view/testing/resolvers.rb
index 68186c3bf8..1fad08a689 100644
--- a/actionview/lib/action_view/testing/resolvers.rb
+++ b/actionview/lib/action_view/testing/resolvers.rb
@@ -22,7 +22,7 @@ module ActionView #:nodoc:
     private
 
       def query(path, exts, _, _)
-        query = "".dup
+        query = +""
         EXTENSIONS.each_key do |ext|
           query << "(" << exts[ext].map { |e| e && Regexp.escape(".#{e}") }.join("|") << "|)"
         end
diff --git a/actionview/test/activerecord/form_helper_activerecord_test.rb b/actionview/test/activerecord/form_helper_activerecord_test.rb
index 1472ee8def..6c44cb9e6c 100644
--- a/actionview/test/activerecord/form_helper_activerecord_test.rb
+++ b/actionview/test/activerecord/form_helper_activerecord_test.rb
@@ -57,7 +57,7 @@ class FormHelperActiveRecordTest < ActionView::TestCase
   private
 
     def hidden_fields(method = nil)
-      txt = %{<input name="utf8" type="hidden" value="&#x2713;" />}.dup
+      txt = +%{<input name="utf8" type="hidden" value="&#x2713;" />}
 
       if method && !%w(get post).include?(method.to_s)
         txt << %{<input name="_method" type="hidden" value="#{method}" />}
@@ -67,7 +67,7 @@ class FormHelperActiveRecordTest < ActionView::TestCase
     end
 
     def form_text(action = "/", id = nil, html_class = nil, remote = nil, multipart = nil, method = nil)
-      txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+      txt =  +%{<form accept-charset="UTF-8" action="#{action}"}
       txt << %{ enctype="multipart/form-data"} if multipart
       txt << %{ data-remote="true"} if remote
       txt << %{ class="#{html_class}"} if html_class
diff --git a/actionview/test/fixtures/ruby_template.ruby b/actionview/test/fixtures/ruby_template.ruby
index 93334610a8..3e0bc445a2 100644
--- a/actionview/test/fixtures/ruby_template.ruby
+++ b/actionview/test/fixtures/ruby_template.ruby
@@ -1,2 +1,2 @@
-body = "".dup
+body = +""
 body << ["Hello", "from", "Ruby", "code"].join(" ")
diff --git a/actionview/test/template/date_helper_test.rb b/actionview/test/template/date_helper_test.rb
index 701e6c86fd..0a294ec674 100644
--- a/actionview/test/template/date_helper_test.rb
+++ b/actionview/test/template/date_helper_test.rb
@@ -214,7 +214,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day
-    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected = +%(<select id="date_day" name="date[day]">\n)
     expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -223,7 +223,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_with_blank
-    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected = +%(<select id="date_day" name="date[day]">\n)
     expected << %(<option value=""></option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -232,7 +232,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_nil_with_blank
-    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected = +%(<select id="date_day" name="date[day]">\n)
     expected << %(<option value=""></option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -240,7 +240,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_with_two_digit_numbers
-    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected = +%(<select id="date_day" name="date[day]">\n)
     expected << %(<option value="1">01</option>\n<option selected="selected" value="2">02</option>\n<option value="3">03</option>\n<option value="4">04</option>\n<option value="5">05</option>\n<option value="6">06</option>\n<option value="7">07</option>\n<option value="8">08</option>\n<option value="9">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -249,7 +249,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_with_html_options
-    expected = %(<select id="date_day" name="date[day]" class="selector">\n).dup
+    expected = +%(<select id="date_day" name="date[day]" class="selector">\n)
     expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -258,7 +258,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_with_default_prompt
-    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected = +%(<select id="date_day" name="date[day]">\n)
     expected << %(<option value="">Day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -266,7 +266,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_with_custom_prompt
-    expected = %(<select id="date_day" name="date[day]">\n).dup
+    expected = +%(<select id="date_day" name="date[day]">\n)
     expected << %(<option value="">Choose day</option>\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -274,7 +274,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_with_generic_with_css_classes
-    expected = %(<select id="date_day" name="date[day]" class="day">\n).dup
+    expected = +%(<select id="date_day" name="date[day]" class="day">\n)
     expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -282,7 +282,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_day_with_custom_with_css_classes
-    expected = %(<select id="date_day" name="date[day]" class="my-day">\n).dup
+    expected = +%(<select id="date_day" name="date[day]" class="my-day">\n)
     expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16" selected="selected">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n)
     expected << "</select>\n"
 
@@ -290,7 +290,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -299,7 +299,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_two_digit_numbers
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="1">01</option>\n<option value="2">02</option>\n<option value="3">03</option>\n<option value="4">04</option>\n<option value="5">05</option>\n<option value="6">06</option>\n<option value="7">07</option>\n<option value="8" selected="selected">08</option>\n<option value="9">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n)
     expected << "</select>\n"
 
@@ -308,7 +308,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_disabled
-    expected = %(<select id="date_month" name="date[month]" disabled="disabled">\n).dup
+    expected = +%(<select id="date_month" name="date[month]" disabled="disabled">\n)
     expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -317,7 +317,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_field_name_override
-    expected = %(<select id="date_mois" name="date[mois]">\n).dup
+    expected = +%(<select id="date_mois" name="date[mois]">\n)
     expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -326,7 +326,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_blank
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value=""></option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -335,7 +335,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_nil_with_blank
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value=""></option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -343,7 +343,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_numbers
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8" selected="selected">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n)
     expected << "</select>\n"
 
@@ -352,7 +352,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_numbers_and_names
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="1">1 - January</option>\n<option value="2">2 - February</option>\n<option value="3">3 - March</option>\n<option value="4">4 - April</option>\n<option value="5">5 - May</option>\n<option value="6">6 - June</option>\n<option value="7">7 - July</option>\n<option value="8" selected="selected">8 - August</option>\n<option value="9">9 - September</option>\n<option value="10">10 - October</option>\n<option value="11">11 - November</option>\n<option value="12">12 - December</option>\n)
     expected << "</select>\n"
 
@@ -361,7 +361,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_format_string
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="1">January (01)</option>\n<option value="2">February (02)</option>\n<option value="3">March (03)</option>\n<option value="4">April (04)</option>\n<option value="5">May (05)</option>\n<option value="6">June (06)</option>\n<option value="7">July (07)</option>\n<option value="8" selected="selected">August (08)</option>\n<option value="9">September (09)</option>\n<option value="10">October (10)</option>\n<option value="11">November (11)</option>\n<option value="12">December (12)</option>\n)
     expected << "</select>\n"
 
@@ -371,7 +371,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_numbers_and_names_with_abbv
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="1">1 - Jan</option>\n<option value="2">2 - Feb</option>\n<option value="3">3 - Mar</option>\n<option value="4">4 - Apr</option>\n<option value="5">5 - May</option>\n<option value="6">6 - Jun</option>\n<option value="7">7 - Jul</option>\n<option value="8" selected="selected">8 - Aug</option>\n<option value="9">9 - Sep</option>\n<option value="10">10 - Oct</option>\n<option value="11">11 - Nov</option>\n<option value="12">12 - Dec</option>\n)
     expected << "</select>\n"
 
@@ -380,7 +380,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_abbv
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="1">Jan</option>\n<option value="2">Feb</option>\n<option value="3">Mar</option>\n<option value="4">Apr</option>\n<option value="5">May</option>\n<option value="6">Jun</option>\n<option value="7">Jul</option>\n<option value="8" selected="selected">Aug</option>\n<option value="9">Sep</option>\n<option value="10">Oct</option>\n<option value="11">Nov</option>\n<option value="12">Dec</option>\n)
     expected << "</select>\n"
 
@@ -391,7 +391,7 @@ class DateHelperTest < ActionView::TestCase
   def test_select_month_with_custom_names
     month_names = %w(nil Januar Februar Marts April Maj Juni Juli August September Oktober November December)
 
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     1.upto(12) { |month| expected << %(<option value="#{month}"#{' selected="selected"' if month == 8}>#{month_names[month]}</option>\n) }
     expected << "</select>\n"
 
@@ -402,7 +402,7 @@ class DateHelperTest < ActionView::TestCase
   def test_select_month_with_zero_indexed_custom_names
     month_names = %w(Januar Februar Marts April Maj Juni Juli August September Oktober November December)
 
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     1.upto(12) { |month| expected << %(<option value="#{month}"#{' selected="selected"' if month == 8}>#{month_names[month - 1]}</option>\n) }
     expected << "</select>\n"
 
@@ -419,7 +419,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_html_options
-    expected = %(<select id="date_month" name="date[month]" class="selector" accesskey="M">\n).dup
+    expected = +%(<select id="date_month" name="date[month]" class="selector" accesskey="M">\n)
     expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -427,7 +427,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_default_prompt
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="">Month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -435,7 +435,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_custom_prompt
-    expected = %(<select id="date_month" name="date[month]">\n).dup
+    expected = +%(<select id="date_month" name="date[month]">\n)
     expected << %(<option value="">Choose month</option>\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -443,7 +443,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_generic_with_css_classes
-    expected = %(<select id="date_month" name="date[month]" class="month">\n).dup
+    expected = +%(<select id="date_month" name="date[month]" class="month">\n)
     expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -451,7 +451,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_month_with_custom_with_css_classes
-    expected = %(<select id="date_month" name="date[month]" class="my-month">\n).dup
+    expected = +%(<select id="date_month" name="date[month]" class="my-month">\n)
     expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -459,7 +459,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year
-    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected = +%(<select id="date_year" name="date[year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -468,7 +468,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_disabled
-    expected = %(<select id="date_year" name="date[year]" disabled="disabled">\n).dup
+    expected = +%(<select id="date_year" name="date[year]" disabled="disabled">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -477,7 +477,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_field_name_override
-    expected = %(<select id="date_annee" name="date[annee]">\n).dup
+    expected = +%(<select id="date_annee" name="date[annee]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -486,7 +486,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_type_discarding
-    expected = %(<select id="date_year" name="date_year">\n).dup
+    expected = +%(<select id="date_year" name="date_year">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -497,7 +497,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_descending
-    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected = +%(<select id="date_year" name="date[year]">\n)
     expected << %(<option value="2005" selected="selected">2005</option>\n<option value="2004">2004</option>\n<option value="2003">2003</option>\n)
     expected << "</select>\n"
 
@@ -514,7 +514,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_html_options
-    expected = %(<select id="date_year" name="date[year]" class="selector" accesskey="M">\n).dup
+    expected = +%(<select id="date_year" name="date[year]" class="selector" accesskey="M">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -522,7 +522,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_default_prompt
-    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected = +%(<select id="date_year" name="date[year]">\n)
     expected << %(<option value="">Year</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -530,7 +530,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_custom_prompt
-    expected = %(<select id="date_year" name="date[year]">\n).dup
+    expected = +%(<select id="date_year" name="date[year]">\n)
     expected << %(<option value="">Choose year</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -538,7 +538,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_generic_with_css_classes
-    expected = %(<select id="date_year" name="date[year]" class="year">\n).dup
+    expected = +%(<select id="date_year" name="date[year]" class="year">\n)
     expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -546,7 +546,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_custom_with_css_classes
-    expected = %(<select id="date_year" name="date[year]" class="my-year">\n).dup
+    expected = +%(<select id="date_year" name="date[year]" class="my-year">\n)
     expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -554,7 +554,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_year_with_position
-    expected = %(<select id="date_year_1i" name="date[year(1i)]">\n).dup
+    expected = +%(<select id="date_year_1i" name="date[year(1i)]">\n)
     expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
     assert_dom_equal expected, select_year(Date.current, include_position: true,  start_year: 2003, end_year: 2005)
@@ -570,7 +570,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour
-    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -578,7 +578,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_ampm
-    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]">\n)
     expected << %(<option value="00">12 AM</option>\n<option value="01">01 AM</option>\n<option value="02">02 AM</option>\n<option value="03">03 AM</option>\n<option value="04">04 AM</option>\n<option value="05">05 AM</option>\n<option value="06">06 AM</option>\n<option value="07">07 AM</option>\n<option value="08" selected="selected">08 AM</option>\n<option value="09">09 AM</option>\n<option value="10">10 AM</option>\n<option value="11">11 AM</option>\n<option value="12">12 PM</option>\n<option value="13">01 PM</option>\n<option value="14">02 PM</option>\n<option value="15">03 PM</option>\n<option value="16">04 PM</option>\n<option value="17">05 PM</option>\n<option value="18">06 PM</option>\n<option value="19">07 PM</option>\n<option value="20">08 PM</option>\n<option value="21">09 PM</option>\n<option value="22">10 PM</option>\n<option value="23">11 PM</option>\n)
     expected << "</select>\n"
 
@@ -586,7 +586,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_disabled
-    expected = %(<select id="date_hour" name="date[hour]" disabled="disabled">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]" disabled="disabled">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -594,7 +594,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_field_name_override
-    expected = %(<select id="date_heure" name="date[heure]">\n).dup
+    expected = +%(<select id="date_heure" name="date[heure]">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -602,7 +602,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_blank
-    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -610,7 +610,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_nil_with_blank
-    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -618,7 +618,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_html_options
-    expected = %(<select id="date_hour" name="date[hour]" class="selector" accesskey="M">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]" class="selector" accesskey="M">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -626,7 +626,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_default_prompt
-    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]">\n)
     expected << %(<option value="">Hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -634,7 +634,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_custom_prompt
-    expected = %(<select id="date_hour" name="date[hour]">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]">\n)
     expected << %(<option value="">Choose hour</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -642,7 +642,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_generic_with_css_classes
-    expected = %(<select id="date_hour" name="date[hour]" class="hour">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]" class="hour">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -650,7 +650,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_hour_with_custom_with_css_classes
-    expected = %(<select id="date_hour" name="date[hour]" class="my-hour">\n).dup
+    expected = +%(<select id="date_hour" name="date[hour]" class="my-hour">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08" selected="selected">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n)
     expected << "</select>\n"
 
@@ -658,7 +658,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute
-    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -666,7 +666,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_disabled
-    expected = %(<select id="date_minute" name="date[minute]" disabled="disabled">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]" disabled="disabled">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -674,7 +674,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_field_name_override
-    expected = %(<select id="date_minuto" name="date[minuto]">\n).dup
+    expected = +%(<select id="date_minuto" name="date[minuto]">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -682,7 +682,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_blank
-    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -690,7 +690,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_blank_and_step
-    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="15">15</option>\n<option value="30">30</option>\n<option value="45">45</option>\n)
     expected << "</select>\n"
 
@@ -698,7 +698,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_nil_with_blank
-    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -706,7 +706,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_nil_with_blank_and_step
-    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="15">15</option>\n<option value="30">30</option>\n<option value="45">45</option>\n)
     expected << "</select>\n"
 
@@ -722,7 +722,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_html_options
-    expected = %(<select id="date_minute" name="date[minute]" class="selector" accesskey="M">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]" class="selector" accesskey="M">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -730,7 +730,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_default_prompt
-    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]">\n)
     expected << %(<option value="">Minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -738,7 +738,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_custom_prompt
-    expected = %(<select id="date_minute" name="date[minute]">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]">\n)
     expected << %(<option value="">Choose minute</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -746,7 +746,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_generic_with_css_classes
-    expected = %(<select id="date_minute" name="date[minute]" class="minute">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]" class="minute">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -754,7 +754,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_minute_with_custom_with_css_classes
-    expected = %(<select id="date_minute" name="date[minute]" class="my-minute">\n).dup
+    expected = +%(<select id="date_minute" name="date[minute]" class="my-minute">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04" selected="selected">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -762,7 +762,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second
-    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected = +%(<select id="date_second" name="date[second]">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -770,7 +770,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_disabled
-    expected = %(<select id="date_second" name="date[second]" disabled="disabled">\n).dup
+    expected = +%(<select id="date_second" name="date[second]" disabled="disabled">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -778,7 +778,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_field_name_override
-    expected = %(<select id="date_segundo" name="date[segundo]">\n).dup
+    expected = +%(<select id="date_segundo" name="date[segundo]">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -786,7 +786,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_blank
-    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected = +%(<select id="date_second" name="date[second]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -794,7 +794,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_nil_with_blank
-    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected = +%(<select id="date_second" name="date[second]">\n)
     expected << %(<option value=""></option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -802,7 +802,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_html_options
-    expected = %(<select id="date_second" name="date[second]" class="selector" accesskey="M">\n).dup
+    expected = +%(<select id="date_second" name="date[second]" class="selector" accesskey="M">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -810,7 +810,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_default_prompt
-    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected = +%(<select id="date_second" name="date[second]">\n)
     expected << %(<option value="">Seconds</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -818,7 +818,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_custom_prompt
-    expected = %(<select id="date_second" name="date[second]">\n).dup
+    expected = +%(<select id="date_second" name="date[second]">\n)
     expected << %(<option value="">Choose seconds</option>\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -826,7 +826,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_generic_with_css_classes
-    expected = %(<select id="date_second" name="date[second]" class="second">\n).dup
+    expected = +%(<select id="date_second" name="date[second]" class="second">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -834,7 +834,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_second_with_custom_with_css_classes
-    expected = %(<select id="date_second" name="date[second]" class="my-second">\n).dup
+    expected = +%(<select id="date_second" name="date[second]" class="my-second">\n)
     expected << %(<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18" selected="selected">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n<option value="32">32</option>\n<option value="33">33</option>\n<option value="34">34</option>\n<option value="35">35</option>\n<option value="36">36</option>\n<option value="37">37</option>\n<option value="38">38</option>\n<option value="39">39</option>\n<option value="40">40</option>\n<option value="41">41</option>\n<option value="42">42</option>\n<option value="43">43</option>\n<option value="44">44</option>\n<option value="45">45</option>\n<option value="46">46</option>\n<option value="47">47</option>\n<option value="48">48</option>\n<option value="49">49</option>\n<option value="50">50</option>\n<option value="51">51</option>\n<option value="52">52</option>\n<option value="53">53</option>\n<option value="54">54</option>\n<option value="55">55</option>\n<option value="56">56</option>\n<option value="57">57</option>\n<option value="58">58</option>\n<option value="59">59</option>\n)
     expected << "</select>\n"
 
@@ -842,7 +842,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -867,7 +867,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_order
-    expected = %(<select id="date_first_month" name="date[first][month]">\n).dup
+    expected = +%(<select id="date_first_month" name="date[first][month]">\n)
     expected << %(<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6">June</option>\n<option value="7">July</option>\n<option value="8" selected="selected">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n)
     expected << "</select>\n"
 
@@ -884,7 +884,7 @@ class DateHelperTest < ActionView::TestCase
 
   def test_select_date_with_incomplete_order
     # Since the order is incomplete nothing will be shown
-    expected = %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n).dup
+    expected = +%(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n)
     expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
     expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="1" />\n)
 
@@ -892,7 +892,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_disabled
-    expected =  %(<select id="date_first_year" name="date[first][year]" disabled="disabled">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]" disabled="disabled">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -908,7 +908,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_no_start_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 1) do |y|
       if y == Date.today.year
         expected << %(<option value="#{y}" selected="selected">#{y}</option>\n)
@@ -932,7 +932,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_no_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     2003.upto(2008) do |y|
       if y == 2003
         expected << %(<option value="#{y}" selected="selected">#{y}</option>\n)
@@ -956,7 +956,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_no_start_or_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 5) do |y|
       if y == Date.today.year
         expected << %(<option value="#{y}" selected="selected">#{y}</option>\n)
@@ -980,7 +980,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_zero_value
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -996,7 +996,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_zero_value_and_no_start_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 1) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -1012,7 +1012,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_zero_value_and_no_end_year
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     last_year = Time.now.year + 5
     2003.upto(last_year) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
@@ -1029,7 +1029,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_zero_value_and_no_start_and_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -1045,7 +1045,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_nil_value_and_no_start_and_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -1061,7 +1061,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_html_options
-    expected =  %(<select id="date_first_year" name="date[first][year]" class="selector">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]" class="selector">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1077,7 +1077,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_separator
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1097,7 +1097,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_separator_and_discard_day
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1113,7 +1113,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_separator_discard_month_and_day
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1124,7 +1124,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_hidden
-    expected =  %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003"/>\n).dup
+    expected =  +%(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003"/>\n)
     expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
     expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="16" />\n)
 
@@ -1133,7 +1133,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_css_classes_option
-    expected =  %(<select id="date_first_year" name="date[first][year]" class="year">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]" class="year">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1149,7 +1149,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_custom_with_css_classes
-    expected =  %(<select id="date_year" name="date[year]" class="my-year">\n).dup
+    expected =  +%(<select id="date_year" name="date[year]" class="my-year">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1165,7 +1165,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_css_classes_option_and_html_class_option
-    expected =  %(<select id="date_first_year" name="date[first][year]" class="datetime optional year">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]" class="datetime optional year">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1181,7 +1181,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_custom_with_css_classes_and_html_class_option
-    expected =  %(<select id="date_year" name="date[year]" class="date optional my-year">\n).dup
+    expected =  +%(<select id="date_year" name="date[year]" class="date optional my-year">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1197,7 +1197,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_partial_with_css_classes_and_html_class_option
-    expected =  %(<select id="date_year" name="date[year]" class="date optional">\n).dup
+    expected =  +%(<select id="date_year" name="date[year]" class="date optional">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1213,7 +1213,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_date_with_html_class_option
-    expected =  %(<select id="date_year" name="date[year]" class="date optional custom-grid">\n).dup
+    expected =  +%(<select id="date_year" name="date[year]" class="date optional custom-grid">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1229,7 +1229,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1257,7 +1257,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_ampm
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1285,7 +1285,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_separators
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1313,7 +1313,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_nil_value_and_no_start_and_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -1341,7 +1341,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_html_options
-    expected =  %(<select id="date_first_year" name="date[first][year]" class="selector">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]" class="selector">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1369,7 +1369,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_all_separators
-    expected =  %(<select id="date_first_year" name="date[first][year]" class="selector">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]" class="selector">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1405,7 +1405,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_default_prompt
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="">Year</option>\n<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1434,7 +1434,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_custom_prompt
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="">Choose year</option>\n<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1463,7 +1463,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_generic_with_css_classes
-    expected =  %(<select id="date_year" name="date[year]" class="year">\n).dup
+    expected =  +%(<select id="date_year" name="date[year]" class="year">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1491,7 +1491,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_custom_with_css_classes
-    expected =  %(<select id="date_year" name="date[year]" class="my-year">\n).dup
+    expected =  +%(<select id="date_year" name="date[year]" class="my-year">\n)
     expected << %(<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1519,7 +1519,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_custom_hours
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     expected << %(<option value="">Choose year</option>\n<option value="2003" selected="selected">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n)
     expected << "</select>\n"
 
@@ -1548,7 +1548,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_datetime_with_hidden
-    expected =  %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n).dup
+    expected =  +%(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n)
     expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
     expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="16" />\n)
     expected << %(<input id="date_first_hour" name="date[first][hour]" type="hidden" value="8" />\n)
@@ -1560,7 +1560,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1579,7 +1579,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_ampm
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1597,7 +1597,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_separator
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
     expected << %(<select id="date_hour" name="date[hour]">\n)
@@ -1615,7 +1615,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_seconds
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1639,7 +1639,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_seconds_and_separator
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1663,7 +1663,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_html_options
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1686,7 +1686,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_default_prompt
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1710,7 +1710,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_custom_prompt
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1735,7 +1735,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_generic_with_css_classes
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1759,7 +1759,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_custom_with_css_classes
-    expected = %(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n).dup
+    expected = +%(<input name="date[year]" id="date_year" value="2003" type="hidden" />\n)
     expected << %(<input name="date[month]" id="date_month" value="8" type="hidden" />\n)
     expected << %(<input name="date[day]" id="date_day" value="16" type="hidden" />\n)
 
@@ -1783,7 +1783,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_select_time_with_hidden
-    expected =  %(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n).dup
+    expected =  +%(<input id="date_first_year" name="date[first][year]" type="hidden" value="2003" />\n)
     expected << %(<input id="date_first_month" name="date[first][month]" type="hidden" value="8" />\n)
     expected << %(<input id="date_first_day" name="date[first][day]" type="hidden" value="16" />\n)
     expected << %(<input id="date_first_hour" name="date[first][hour]" type="hidden" value="8" />\n)
@@ -1797,7 +1797,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -1817,7 +1817,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -1837,7 +1837,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -1875,7 +1875,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = "<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n".dup
+    expected = +"<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n"
 
     expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
     expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
@@ -1892,7 +1892,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 2, 29)
 
-    expected = "<input type=\"hidden\" id=\"post_written_on_2i\" name=\"post[written_on(2i)]\" value=\"2\" />\n".dup
+    expected = +"<input type=\"hidden\" id=\"post_written_on_2i\" name=\"post[written_on(2i)]\" value=\"2\" />\n"
     expected << "<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n"
 
     expected << %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
@@ -1906,7 +1906,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = "<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n".dup
+    expected = +"<input type=\"hidden\" id=\"post_written_on_3i\" name=\"post[written_on(3i)]\" value=\"1\" />\n"
 
     expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n}
     expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
@@ -1925,7 +1925,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = "<input type=\"hidden\" id=\"post_written_on_3i\" disabled=\"disabled\" name=\"post[written_on(3i)]\" value=\"1\" />\n".dup
+    expected = +"<input type=\"hidden\" id=\"post_written_on_3i\" disabled=\"disabled\" name=\"post[written_on(3i)]\" value=\"1\" />\n"
 
     expected << %{<select id="post_written_on_2i" disabled="disabled" name="post[written_on(2i)]">\n}
     expected << %{<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option value="6" selected="selected">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n}
@@ -1946,7 +1946,7 @@ class DateHelperTest < ActionView::TestCase
       concat f.date_select(:written_on)
     end
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}
     expected << %{<select id="post_written_on_2i" name="post[written_on(2i)]">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
     expected << %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
 
@@ -1962,7 +1962,7 @@ class DateHelperTest < ActionView::TestCase
       concat f.date_select(:written_on)
     end
 
-    expected = %{<select id="post_#{id}_written_on_1i" name="post[#{id}][written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected = +%{<select id="post_#{id}_written_on_1i" name="post[#{id}][written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}
     expected << %{<select id="post_#{id}_written_on_2i" name="post[#{id}][written_on(2i)]">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
     expected << %{<select id="post_#{id}_written_on_3i" name="post[#{id}][written_on(3i)]">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
 
@@ -1978,7 +1978,7 @@ class DateHelperTest < ActionView::TestCase
       concat f.date_select(:written_on)
     end
 
-    expected = %{<select id="post_#{id}_written_on_1i" name="post[#{id}][written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected = +%{<select id="post_#{id}_written_on_1i" name="post[#{id}][written_on(1i)]">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}
     expected << %{<select id="post_#{id}_written_on_2i" name="post[#{id}][written_on(2i)]">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
     expected << %{<select id="post_#{id}_written_on_3i" name="post[#{id}][written_on(3i)]">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
 
@@ -1990,7 +1990,7 @@ class DateHelperTest < ActionView::TestCase
     @post.written_on = Date.new(2004, 6, 15)
     id = 456
 
-    expected = %{<select id="post_456_written_on_1i" name="post[#{id}][written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_456_written_on_1i" name="post[#{id}][written_on(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2010,7 +2010,7 @@ class DateHelperTest < ActionView::TestCase
     @post.written_on = Date.new(2004, 6, 15)
     id = 123
 
-    expected = %{<select id="post_123_written_on_1i" name="post[#{id}][written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_123_written_on_1i" name="post[#{id}][written_on(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2029,7 +2029,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}.dup
+    expected = +%{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
     1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
     expected << "</select>\n"
 
@@ -2049,7 +2049,7 @@ class DateHelperTest < ActionView::TestCase
 
     start_year = Time.now.year - 5
     end_year   = Time.now.year + 5
-    expected =   %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected =   +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     start_year.upto(end_year) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == Time.now.year}>#{i}</option>\n) }
     expected << "</select>\n"
 
@@ -2069,7 +2069,7 @@ class DateHelperTest < ActionView::TestCase
 
     start_year = Time.now.year - 5
     end_year   = Time.now.year + 5
-    expected =   %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected =   +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << "<option value=\"\"></option>\n"
     start_year.upto(end_year) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
     expected << "</select>\n"
@@ -2113,7 +2113,7 @@ class DateHelperTest < ActionView::TestCase
     start_year = Time.now.year - 5
     end_year   = Time.now.year + 5
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << "<option value=\"\"></option>\n"
     start_year.upto(end_year) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
     expected << "</select>\n"
@@ -2145,7 +2145,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2164,7 +2164,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="selector">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]" class="selector">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2188,7 +2188,7 @@ class DateHelperTest < ActionView::TestCase
       concat f.date_select(:written_on, {}, { class: "selector" })
     end
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="selector">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]" class="selector">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2208,7 +2208,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2232,7 +2232,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}.dup
+    expected = +%{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
     expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
     expected << "</select>\n"
 
@@ -2255,7 +2255,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}.dup
+    expected = +%{<select id="post_written_on_3i" name="post[written_on(3i)]">\n}
     expected << %{<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15" selected="selected">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n}
     expected << "</select>\n"
 
@@ -2273,7 +2273,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << %{<option value="">Year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2293,7 +2293,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]">\n}
     expected << %{<option value="">Choose year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2313,7 +2313,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="year">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]" class="year">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2333,7 +2333,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Date.new(2004, 6, 15)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="my-year">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]" class="my-year">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2353,7 +2353,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2372,7 +2372,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2391,7 +2391,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="1" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="1" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="1" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="1" />\n}
 
@@ -2410,7 +2410,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %(<select id="post_written_on_4i" name="post[written_on(4i)]">\n).dup
+    expected = +%(<select id="post_written_on_4i" name="post[written_on(4i)]">\n)
     0.upto(23) { |i| expected << %(<option value="#{sprintf("%02d", i)}"#{' selected="selected"' if i == 15}>#{sprintf("%02d", i)}</option>\n) }
     expected << "</select>\n"
     expected << " : "
@@ -2425,7 +2425,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2448,7 +2448,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2471,7 +2471,7 @@ class DateHelperTest < ActionView::TestCase
       concat f.time_select(:written_on, {}, { class: "selector" })
     end
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2490,7 +2490,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2517,7 +2517,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2538,7 +2538,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2559,7 +2559,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2580,7 +2580,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2601,7 +2601,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_written_on_1i" disabled="disabled" name="post[written_on(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_written_on_1i" disabled="disabled" name="post[written_on(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_written_on_2i" disabled="disabled" name="post[written_on(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_written_on_3i" disabled="disabled" name="post[written_on(3i)]" value="15" />\n}
 
@@ -2620,7 +2620,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2649,7 +2649,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2715,7 +2715,7 @@ class DateHelperTest < ActionView::TestCase
 
     @post = Post.new
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2750,7 +2750,7 @@ class DateHelperTest < ActionView::TestCase
       concat f.datetime_select(:updated_at, {}, { class: "selector" })
     end
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]" class="selector">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]" class="selector">\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option selected="selected" value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n</select>\n}
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]" class="selector">\n<option value="1">January</option>\n<option value="2">February</option>\n<option value="3">March</option>\n<option value="4">April</option>\n<option value="5">May</option>\n<option selected="selected" value="6">June</option>\n<option value="7">July</option>\n<option value="8">August</option>\n<option value="9">September</option>\n<option value="10">October</option>\n<option value="11">November</option>\n<option value="12">December</option>\n</select>\n}
     expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]" class="selector">\n<option value="1">1</option>\n<option value="2">2</option>\n<option value="3">3</option>\n<option value="4">4</option>\n<option value="5">5</option>\n<option value="6">6</option>\n<option value="7">7</option>\n<option value="8">8</option>\n<option value="9">9</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option selected="selected" value="15">15</option>\n<option value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n<option value="24">24</option>\n<option value="25">25</option>\n<option value="26">26</option>\n<option value="27">27</option>\n<option value="28">28</option>\n<option value="29">29</option>\n<option value="30">30</option>\n<option value="31">31</option>\n</select>\n}
     expected << %{ &mdash; <select id="post_updated_at_4i" name="post[updated_at(4i)]" class="selector">\n<option value="00">00</option>\n<option value="01">01</option>\n<option value="02">02</option>\n<option value="03">03</option>\n<option value="04">04</option>\n<option value="05">05</option>\n<option value="06">06</option>\n<option value="07">07</option>\n<option value="08">08</option>\n<option value="09">09</option>\n<option value="10">10</option>\n<option value="11">11</option>\n<option value="12">12</option>\n<option value="13">13</option>\n<option value="14">14</option>\n<option value="15">15</option>\n<option selected="selected" value="16">16</option>\n<option value="17">17</option>\n<option value="18">18</option>\n<option value="19">19</option>\n<option value="20">20</option>\n<option value="21">21</option>\n<option value="22">22</option>\n<option value="23">23</option>\n</select>\n}
@@ -2763,7 +2763,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2816,7 +2816,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = nil
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     expected << %{<option value="">Year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2845,7 +2845,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = nil
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     expected << %{<option value="">Choose year</option>\n<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2874,7 +2874,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="year">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]" class="year">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2903,7 +2903,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.written_on = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_written_on_1i" name="post[written_on(1i)]" class="my-year">\n}.dup
+    expected = +%{<select id="post_written_on_1i" name="post[written_on(1i)]" class="my-year">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -2929,7 +2929,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_date_select_with_zero_value_and_no_start_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 1) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -2945,7 +2945,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_date_select_with_zero_value_and_no_end_year
-    expected =  %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected =  +%(<select id="date_first_year" name="date[first][year]">\n)
     last_year = Time.now.year + 5
     2003.upto(last_year) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
@@ -2962,7 +2962,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_date_select_with_zero_value_and_no_start_and_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -2978,7 +2978,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_date_select_with_nil_value_and_no_start_and_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -2994,7 +2994,7 @@ class DateHelperTest < ActionView::TestCase
   end
 
   def test_datetime_select_with_nil_value_and_no_start_and_end_year
-    expected = %(<select id="date_first_year" name="date[first][year]">\n).dup
+    expected = +%(<select id="date_first_year" name="date[first][year]">\n)
     (Date.today.year - 5).upto(Date.today.year + 5) { |y| expected << %(<option value="#{y}">#{y}</option>\n) }
     expected << "</select>\n"
 
@@ -3026,7 +3026,7 @@ class DateHelperTest < ActionView::TestCase
     @post.updated_at = Time.local(2004, 6, 15, 16, 35)
     id = 456
 
-    expected = %{<select id="post_456_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_456_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -3060,7 +3060,7 @@ class DateHelperTest < ActionView::TestCase
       concat f.datetime_select(:updated_at)
     end
 
-    expected = %{<select id="post_456_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_456_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -3090,7 +3090,7 @@ class DateHelperTest < ActionView::TestCase
     @post.updated_at = Time.local(2004, 6, 15, 16, 35)
     id = @post.id
 
-    expected = %{<select id="post_123_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_123_updated_at_1i" name="post[#{id}][updated_at(1i)]">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
@@ -3119,7 +3119,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
@@ -3150,7 +3150,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
     1.upto(12) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 6}>#{Date::MONTHNAMES[i]}</option>\n) }
     expected << "</select>\n"
@@ -3175,7 +3175,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<input type="hidden" id="post_updated_at_2i" name="post[updated_at(2i)]" value="6" />\n}
@@ -3198,7 +3198,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_updated_at_2i" name="post[updated_at(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_updated_at_3i" name="post[updated_at(3i)]" value="1" />\n}
 
@@ -3217,7 +3217,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_updated_at_1i" disabled="disabled" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_updated_at_1i" disabled="disabled" name="post[updated_at(1i)]" value="2004" />\n}
     expected << %{<input type="hidden" id="post_updated_at_2i" disabled="disabled" name="post[updated_at(2i)]" value="6" />\n}
     expected << %{<input type="hidden" id="post_updated_at_3i" disabled="disabled" name="post[updated_at(3i)]" value="1" />\n}
 
@@ -3236,7 +3236,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
@@ -3253,7 +3253,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
@@ -3277,7 +3277,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" disabled="disabled" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" disabled="disabled" name="post[updated_at(1i)]">\n}
     1999.upto(2009) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2004}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<select id="post_updated_at_2i" disabled="disabled" name="post[updated_at(2i)]">\n}
@@ -3301,7 +3301,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
     1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
@@ -3328,7 +3328,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 15, 16, 35)
 
-    expected = %{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}.dup
+    expected = +%{<input type="hidden" id="post_updated_at_1i" name="post[updated_at(1i)]" value="2004" />\n}
     expected << %{<select id="post_updated_at_3i" name="post[updated_at(3i)]">\n}
     1.upto(31) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 15}>#{i}</option>\n) }
     expected << "</select>\n"
@@ -3353,7 +3353,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = nil
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     2001.upto(2011) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == 2006}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
@@ -3380,7 +3380,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = nil
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     expected << %(<option value=""></option>\n)
     (Time.now.year - 5).upto(Time.now.year + 5) { |i| expected << %(<option value="#{i}">#{i}</option>\n) }
     expected << "</select>\n"
@@ -3400,7 +3400,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = nil
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]">\n}
     (Time.now.year - 5).upto(Time.now.year + 5) { |i| expected << %(<option value="#{i}"#{' selected="selected"' if i == Time.now.year}>#{i}</option>\n) }
     expected << "</select>\n"
     expected << %{<select id="post_updated_at_2i" name="post[updated_at(2i)]">\n}
@@ -3427,7 +3427,7 @@ class DateHelperTest < ActionView::TestCase
     @post = Post.new
     @post.updated_at = Time.local(2004, 6, 15, 16, 35)
 
-    expected = %{<select id="post_updated_at_1i" name="post[updated_at(1i)]" class="selector">\n}.dup
+    expected = +%{<select id="post_updated_at_1i" name="post[updated_at(1i)]" class="selector">\n}
     expected << %{<option value="1999">1999</option>\n<option value="2000">2000</option>\n<option value="2001">2001</option>\n<option value="2002">2002</option>\n<option value="2003">2003</option>\n<option value="2004" selected="selected">2004</option>\n<option value="2005">2005</option>\n<option value="2006">2006</option>\n<option value="2007">2007</option>\n<option value="2008">2008</option>\n<option value="2009">2009</option>\n}
     expected << "</select>\n"
 
diff --git a/actionview/test/template/form_helper/form_with_test.rb b/actionview/test/template/form_helper/form_with_test.rb
index c30176349c..876e799d93 100644
--- a/actionview/test/template/form_helper/form_with_test.rb
+++ b/actionview/test/template/form_helper/form_with_test.rb
@@ -37,7 +37,7 @@ class FormWithActsLikeFormTagTest < FormWithTest
     method = options[:method]
     skip_enforcing_utf8 = options.fetch(:skip_enforcing_utf8, false)
 
-    "".dup.tap do |txt|
+    (+"").tap do |txt|
       unless skip_enforcing_utf8
         txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
       end
@@ -53,7 +53,7 @@ class FormWithActsLikeFormTagTest < FormWithTest
 
     method = method.to_s == "get" ? "get" : "post"
 
-    txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+    txt =  +%{<form accept-charset="UTF-8" action="#{action}"}
     txt << %{ enctype="multipart/form-data"} if enctype
     txt << %{ data-remote="true"} unless local
     txt << %{ class="#{html_class}"} if html_class
@@ -2325,9 +2325,9 @@ class FormWithActsLikeFormForTest < FormWithTest
       method = options[:method]
 
       if options.fetch(:skip_enforcing_utf8, false)
-        txt = "".dup
+        txt = +""
       else
-        txt = %{<input name="utf8" type="hidden" value="&#x2713;" />}.dup
+        txt = +%{<input name="utf8" type="hidden" value="&#x2713;" />}
       end
 
       if method && !%w(get post).include?(method.to_s)
@@ -2338,7 +2338,7 @@ class FormWithActsLikeFormForTest < FormWithTest
     end
 
     def form_text(action = "/", id = nil, html_class = nil, local = nil, multipart = nil, method = nil)
-      txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+      txt =  +%{<form accept-charset="UTF-8" action="#{action}"}
       txt << %{ enctype="multipart/form-data"} if multipart
       txt << %{ data-remote="true"} unless local
       txt << %{ class="#{html_class}"} if html_class
diff --git a/actionview/test/template/form_helper_test.rb b/actionview/test/template/form_helper_test.rb
index 38bb1e1d24..a76b2616fd 100644
--- a/actionview/test/template/form_helper_test.rb
+++ b/actionview/test/template/form_helper_test.rb
@@ -3558,9 +3558,9 @@ class FormHelperTest < ActionView::TestCase
       method = options[:method]
 
       if options.fetch(:enforce_utf8, true)
-        txt = %{<input name="utf8" type="hidden" value="&#x2713;" />}.dup
+        txt = +%{<input name="utf8" type="hidden" value="&#x2713;" />}
       else
-        txt = "".dup
+        txt = +""
       end
 
       if method && !%w(get post).include?(method.to_s)
@@ -3571,7 +3571,7 @@ class FormHelperTest < ActionView::TestCase
     end
 
     def form_text(action = "/", id = nil, html_class = nil, remote = nil, multipart = nil, method = nil)
-      txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+      txt =  +%{<form accept-charset="UTF-8" action="#{action}"}
       txt << %{ enctype="multipart/form-data"} if multipart
       txt << %{ data-remote="true"} if remote
       txt << %{ class="#{html_class}"} if html_class
diff --git a/actionview/test/template/form_tag_helper_test.rb b/actionview/test/template/form_tag_helper_test.rb
index a3500a7eb3..9ece9f3ad1 100644
--- a/actionview/test/template/form_tag_helper_test.rb
+++ b/actionview/test/template/form_tag_helper_test.rb
@@ -26,7 +26,7 @@ class FormTagHelperTest < ActionView::TestCase
     method = options[:method]
     enforce_utf8 = options.fetch(:enforce_utf8, true)
 
-    "".dup.tap do |txt|
+    (+"").tap do |txt|
       if enforce_utf8
         txt << %{<input name="utf8" type="hidden" value="&#x2713;" />}
       end
@@ -42,7 +42,7 @@ class FormTagHelperTest < ActionView::TestCase
 
     method = method.to_s == "get" ? "get" : "post"
 
-    txt =  %{<form accept-charset="UTF-8" action="#{action}"}.dup
+    txt =  +%{<form accept-charset="UTF-8" action="#{action}"}
     txt << %{ enctype="multipart/form-data"} if enctype
     txt << %{ data-remote="true"} if remote
     txt << %{ class="#{html_class}"} if html_class
diff --git a/actionview/test/template/javascript_helper_test.rb b/actionview/test/template/javascript_helper_test.rb
index 80de541bf1..4c28aeaee1 100644
--- a/actionview/test/template/javascript_helper_test.rb
+++ b/actionview/test/template/javascript_helper_test.rb
@@ -30,8 +30,8 @@ class JavaScriptHelperTest < ActionView::TestCase
     assert_equal %(This \\"thing\\" is really\\n netos\\'), escape_javascript(%(This "thing" is really\n netos'))
     assert_equal %(backslash\\\\test), escape_javascript(%(backslash\\test))
     assert_equal %(dont <\\/close> tags), escape_javascript(%(dont </close> tags))
-    assert_equal %(unicode &#x2028; newline), escape_javascript(%(unicode \342\200\250 newline).dup.force_encoding(Encoding::UTF_8).encode!)
-    assert_equal %(unicode &#x2029; newline), escape_javascript(%(unicode \342\200\251 newline).dup.force_encoding(Encoding::UTF_8).encode!)
+    assert_equal %(unicode &#x2028; newline), escape_javascript((+%(unicode \342\200\250 newline)).force_encoding(Encoding::UTF_8).encode!)
+    assert_equal %(unicode &#x2029; newline), escape_javascript((+%(unicode \342\200\251 newline)).force_encoding(Encoding::UTF_8).encode!)
 
     assert_equal %(dont <\\/close> tags), j(%(dont </close> tags))
   end
diff --git a/actionview/test/template/render_test.rb b/actionview/test/template/render_test.rb
index 6ff7ddba0f..afe68b7ff0 100644
--- a/actionview/test/template/render_test.rb
+++ b/actionview/test/template/render_test.rb
@@ -585,7 +585,7 @@ module RenderTestCases
 
   def test_render_with_passing_couple_extensions_to_one_register_template_handler_function_call
     ActionView::Template.register_template_handler :foo1, :foo2, CustomHandler
-    assert_equal @view.render(inline: "Hello, World!".dup, type: :foo1), @view.render(inline: "Hello, World!".dup, type: :foo2)
+    assert_equal @view.render(inline: +"Hello, World!", type: :foo1), @view.render(inline: +"Hello, World!", type: :foo2)
   ensure
     ActionView::Template.unregister_template_handler :foo1, :foo2
   end
diff --git a/actionview/test/template/streaming_render_test.rb b/actionview/test/template/streaming_render_test.rb
index ef000300cc..f196c42c4f 100644
--- a/actionview/test/template/streaming_render_test.rb
+++ b/actionview/test/template/streaming_render_test.rb
@@ -19,7 +19,7 @@ class SetupFiberedBase < ActiveSupport::TestCase
 
   def buffered_render(options)
     body = render_body(options)
-    string = "".dup
+    string = +""
     body.each do |piece|
       string << piece
     end
diff --git a/actionview/test/template/text_helper_test.rb b/actionview/test/template/text_helper_test.rb
index 4d47706bda..c4e420a95b 100644
--- a/actionview/test/template/text_helper_test.rb
+++ b/actionview/test/template/text_helper_test.rb
@@ -13,7 +13,7 @@ class TextHelperTest < ActionView::TestCase
   end
 
   def test_concat
-    self.output_buffer = "foo".dup
+    self.output_buffer = +"foo"
     assert_equal "foobar", concat("bar")
     assert_equal "foobar", output_buffer
   end
@@ -106,8 +106,8 @@ class TextHelperTest < ActionView::TestCase
   end
 
   def test_truncate_multibyte
-    assert_equal "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...".dup.force_encoding(Encoding::UTF_8),
-      truncate("\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244".dup.force_encoding(Encoding::UTF_8), length: 10)
+    assert_equal (+"\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...").force_encoding(Encoding::UTF_8),
+      truncate((+"\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244").force_encoding(Encoding::UTF_8), length: 10)
   end
 
   def test_truncate_does_not_modify_the_options_hash
@@ -327,7 +327,7 @@ class TextHelperTest < ActionView::TestCase
   end
 
   def test_excerpt_with_utf8
-    assert_equal("...\357\254\203ciency could not be...".dup.force_encoding(Encoding::UTF_8), excerpt("That's why e\357\254\203ciency could not be helped".dup.force_encoding(Encoding::UTF_8), "could", radius: 8))
+    assert_equal((+"...\357\254\203ciency could not be...").force_encoding(Encoding::UTF_8), excerpt((+"That's why e\357\254\203ciency could not be helped").force_encoding(Encoding::UTF_8), "could", radius: 8))
   end
 
   def test_excerpt_does_not_modify_the_options_hash
diff --git a/actionview/test/template/url_helper_test.rb b/actionview/test/template/url_helper_test.rb
index 9d91dbb72b..7b77bae30d 100644
--- a/actionview/test/template/url_helper_test.rb
+++ b/actionview/test/template/url_helper_test.rb
@@ -548,7 +548,7 @@ class UrlHelperTest < ActiveSupport::TestCase
 
   def test_current_page_with_escaped_params_with_different_encoding
     @request = request_for_url("/")
-    @request.stub(:path, "/category/administra%c3%a7%c3%a3o".dup.force_encoding(Encoding::ASCII_8BIT)) do
+    @request.stub(:path, (+"/category/administra%c3%a7%c3%a3o").force_encoding(Encoding::ASCII_8BIT)) do
       assert current_page?(controller: "foo", action: "category", category: "administração")
       assert current_page?("http://www.example.com/category/administra%c3%a7%c3%a3o")
     end
diff --git a/activemodel/test/cases/attribute_test.rb b/activemodel/test/cases/attribute_test.rb
index ea2b0efd11..20c02e689c 100644
--- a/activemodel/test/cases/attribute_test.rb
+++ b/activemodel/test/cases/attribute_test.rb
@@ -78,7 +78,7 @@ module ActiveModel
     end
 
     test "duping dups the value" do
-      @type.expect(:deserialize, "type cast".dup, ["a value"])
+      @type.expect(:deserialize, +"type cast", ["a value"])
       attribute = Attribute.from_database(nil, "a value", @type)
 
       value_from_orig = attribute.value
@@ -246,7 +246,7 @@ module ActiveModel
     end
 
     test "with_type preserves mutations" do
-      attribute = Attribute.from_database(:foo, "".dup, Type::Value.new)
+      attribute = Attribute.from_database(:foo, +"", Type::Value.new)
       attribute.value << "1"
 
       assert_equal 1, attribute.with_type(Type::Integer.new).value
diff --git a/activemodel/test/cases/dirty_test.rb b/activemodel/test/cases/dirty_test.rb
index b38d84fff2..0edbbffa86 100644
--- a/activemodel/test/cases/dirty_test.rb
+++ b/activemodel/test/cases/dirty_test.rb
@@ -94,7 +94,7 @@ class DirtyTest < ActiveModel::TestCase
   end
 
   test "attribute mutation" do
-    @model.instance_variable_set("@name", "Yam".dup)
+    @model.instance_variable_set("@name", +"Yam")
     assert_not_predicate @model, :name_changed?
     @model.name.replace("Hadad")
     assert_not_predicate @model, :name_changed?
diff --git a/activemodel/test/cases/type/string_test.rb b/activemodel/test/cases/type/string_test.rb
index 825c8bb246..5469fdb7af 100644
--- a/activemodel/test/cases/type/string_test.rb
+++ b/activemodel/test/cases/type/string_test.rb
@@ -15,7 +15,7 @@ module ActiveModel
       test "cast strings are mutable" do
         type = Type::String.new
 
-        s = "foo".dup
+        s = +"foo"
         assert_equal false, type.cast(s).frozen?
         assert_equal false, s.frozen?
 
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
index e977d36cb9..99934a0e31 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/connection_pool.rb
@@ -731,7 +731,7 @@ module ActiveRecord
           # this block can't be easily moved into attempt_to_checkout_all_existing_connections's
           # rescue block, because doing so would put it outside of synchronize section, without
           # being in a critical section thread_report might become inaccurate
-          msg = "could not obtain ownership of all database connections in #{checkout_timeout} seconds".dup
+          msg = +"could not obtain ownership of all database connections in #{checkout_timeout} seconds"
 
           thread_report = []
           @connections.each do |conn|
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
index 5b24a467ec..c10da813ec 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb
@@ -379,7 +379,7 @@ module ActiveRecord
           build_fixture_sql(fixtures, table_name)
         end.compact
 
-        table_deletes = tables_to_delete.map { |table| "DELETE FROM #{quote_table_name table}".dup }
+        table_deletes = tables_to_delete.map { |table| +"DELETE FROM #{quote_table_name table}" }
         total_sql = Array.wrap(combine_multi_statements(table_deletes + fixture_inserts))
 
         disable_referential_integrity do
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
index 529c9d8ca6..9d9e8a4110 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_creation.rb
@@ -21,7 +21,7 @@ module ActiveRecord
         private
 
           def visit_AlterTable(o)
-            sql = "ALTER TABLE #{quote_table_name(o.name)} ".dup
+            sql = +"ALTER TABLE #{quote_table_name(o.name)} "
             sql << o.adds.map { |col| accept col }.join(" ")
             sql << o.foreign_key_adds.map { |fk| visit_AddForeignKey fk }.join(" ")
             sql << o.foreign_key_drops.map { |fk| visit_DropForeignKey fk }.join(" ")
@@ -29,17 +29,17 @@ module ActiveRecord
 
           def visit_ColumnDefinition(o)
             o.sql_type = type_to_sql(o.type, o.options)
-            column_sql = "#{quote_column_name(o.name)} #{o.sql_type}".dup
+            column_sql = +"#{quote_column_name(o.name)} #{o.sql_type}"
             add_column_options!(column_sql, column_options(o)) unless o.type == :primary_key
             column_sql
           end
 
           def visit_AddColumnDefinition(o)
-            "ADD #{accept(o.column)}".dup
+            +"ADD #{accept(o.column)}"
           end
 
           def visit_TableDefinition(o)
-            create_sql = "CREATE#{' TEMPORARY' if o.temporary} TABLE #{quote_table_name(o.name)} ".dup
+            create_sql = +"CREATE#{' TEMPORARY' if o.temporary} TABLE #{quote_table_name(o.name)} "
 
             statements = o.columns.map { |c| accept c }
             statements << accept(o.primary_keys) if o.primary_keys
diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index 172f0a5c84..723d8c318d 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -1380,7 +1380,7 @@ module ActiveRecord
           sm_table = quote_table_name(ActiveRecord::SchemaMigration.table_name)
 
           if versions.is_a?(Array)
-            sql = "INSERT INTO #{sm_table} (version) VALUES\n".dup
+            sql = +"INSERT INTO #{sm_table} (version) VALUES\n"
             sql << versions.map { |v| "(#{quote(v)})" }.join(",\n")
             sql << ";\n\n"
             sql
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
index 42ed9ce82d..79aafc956f 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_adapter.rb
@@ -162,7 +162,7 @@ module ActiveRecord
       # this method must only be called while holding connection pool's mutex
       def lease
         if in_use?
-          msg = "Cannot lease connection, ".dup
+          msg = +"Cannot lease connection, "
           if @owner == Thread.current
             msg << "it is already leased by the current thread."
           else
diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index af37fcc1f1..09242a0f14 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -137,7 +137,7 @@ module ActiveRecord
       end
 
       def index_algorithms
-        { default: "ALGORITHM = DEFAULT".dup, copy: "ALGORITHM = COPY".dup, inplace: "ALGORITHM = INPLACE".dup }
+        { default: +"ALGORITHM = DEFAULT", copy: +"ALGORITHM = COPY", inplace: +"ALGORITHM = INPLACE" }
       end
 
       # HELPER METHODS ===========================================
@@ -392,7 +392,7 @@ module ActiveRecord
 
       def add_index(table_name, column_name, options = {}) #:nodoc:
         index_name, index_type, index_columns, _, index_algorithm, index_using, comment = add_index_options(table_name, column_name, options)
-        sql = "CREATE #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} ON #{quote_table_name(table_name)} (#{index_columns}) #{index_algorithm}".dup
+        sql = +"CREATE #{index_type} INDEX #{quote_column_name(index_name)} #{index_using} ON #{quote_table_name(table_name)} (#{index_columns}) #{index_algorithm}"
         execute add_sql_comment!(sql, comment)
       end
 
@@ -785,7 +785,7 @@ module ActiveRecord
           # https://dev.mysql.com/doc/refman/5.7/en/set-names.html
           # (trailing comma because variable_assignments will always have content)
           if @config[:encoding]
-            encoding = "NAMES #{@config[:encoding]}".dup
+            encoding = +"NAMES #{@config[:encoding]}"
             encoding << " COLLATE #{@config[:collation]}" if @config[:collation]
             encoding << ", "
           end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_creation.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_creation.rb
index c9ea653b77..82ed320617 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/schema_creation.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_creation.rb
@@ -17,7 +17,7 @@ module ActiveRecord
           end
 
           def visit_ChangeColumnDefinition(o)
-            change_column_sql = "CHANGE #{quote_column_name(o.name)} #{accept(o.column)}".dup
+            change_column_sql = +"CHANGE #{quote_column_name(o.name)} #{accept(o.column)}"
             add_column_position!(change_column_sql, column_options(o.column))
           end
 
@@ -64,7 +64,7 @@ module ActiveRecord
 
           def index_in_create(table_name, column_name, options)
             index_name, index_type, index_columns, _, _, index_using, comment = @conn.add_index_options(table_name, column_name, options)
-            add_sql_comment!("#{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})".dup, comment)
+            add_sql_comment!((+"#{index_type} INDEX #{quote_column_name(index_name)} #{index_using} (#{index_columns})"), comment)
           end
       end
     end
diff --git a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
index 1cf210d85b..e167c01802 100644
--- a/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/mysql/schema_statements.rb
@@ -121,7 +121,7 @@ module ActiveRecord
           def data_source_sql(name = nil, type: nil)
             scope = quoted_scope(name, type: type)
 
-            sql = "SELECT table_name FROM information_schema.tables".dup
+            sql = +"SELECT table_name FROM information_schema.tables"
             sql << " WHERE table_schema = #{scope[:schema]}"
             sql << " AND table_name = #{scope[:name]}" if scope[:name]
             sql << " AND table_type = #{scope[:type]}" if scope[:type]
diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 00da7690a2..fae3ddbad4 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -686,7 +686,7 @@ module ActiveRecord
           def change_column_sql(table_name, column_name, type, options = {})
             quoted_column_name = quote_column_name(column_name)
             sql_type = type_to_sql(type, options)
-            sql = "ALTER COLUMN #{quoted_column_name} TYPE #{sql_type}".dup
+            sql = +"ALTER COLUMN #{quoted_column_name} TYPE #{sql_type}"
             if options[:collation]
               sql << " COLLATE \"#{options[:collation]}\""
             end
@@ -757,7 +757,7 @@ module ActiveRecord
             scope = quoted_scope(name, type: type)
             scope[:type] ||= "'r','v','m','p','f'" # (r)elation/table, (v)iew, (m)aterialized view, (p)artitioned table, (f)oreign table
 
-            sql = "SELECT c.relname FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace".dup
+            sql = +"SELECT c.relname FROM pg_class c LEFT JOIN pg_namespace n ON n.oid = c.relnamespace"
             sql << " WHERE n.nspname = #{scope[:schema]}"
             sql << " AND c.relname = #{scope[:name]}" if scope[:name]
             sql << " AND c.relkind IN (#{scope[:type]})"
diff --git a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
index 46ca7e07a9..48277f0ae2 100644
--- a/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/sqlite3/schema_statements.rb
@@ -86,7 +86,7 @@ module ActiveRecord
             scope = quoted_scope(name, type: type)
             scope[:type] ||= "'table','view'"
 
-            sql = "SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence'".dup
+            sql = +"SELECT name FROM sqlite_master WHERE name <> 'sqlite_sequence'"
             sql << " AND name = #{scope[:name]}" if scope[:name]
             sql << " AND type IN (#{scope[:type]})"
             sql
diff --git a/activerecord/lib/active_record/explain.rb b/activerecord/lib/active_record/explain.rb
index 7ccb938888..919e96cd7a 100644
--- a/activerecord/lib/active_record/explain.rb
+++ b/activerecord/lib/active_record/explain.rb
@@ -18,7 +18,7 @@ module ActiveRecord
     # Returns a formatted string ready to be logged.
     def exec_explain(queries) # :nodoc:
       str = queries.map do |sql, binds|
-        msg = "EXPLAIN for: #{sql}".dup
+        msg = +"EXPLAIN for: #{sql}"
         unless binds.empty?
           msg << " "
           msg << binds.map { |attr| render_bind(attr) }.inspect
diff --git a/activerecord/lib/active_record/migration.rb b/activerecord/lib/active_record/migration.rb
index 807b882bfb..9651e69edd 100644
--- a/activerecord/lib/active_record/migration.rb
+++ b/activerecord/lib/active_record/migration.rb
@@ -161,7 +161,7 @@ module ActiveRecord
 
   class ProtectedEnvironmentError < ActiveRecordError #:nodoc:
     def initialize(env = "production")
-      msg = "You are attempting to run a destructive action against your '#{env}' database.\n".dup
+      msg = +"You are attempting to run a destructive action against your '#{env}' database.\n"
       msg << "If you are sure you want to continue, run the same command with the environment variable:\n"
       msg << "DISABLE_DATABASE_ENVIRONMENT_CHECK=1"
       super(msg)
@@ -170,7 +170,7 @@ module ActiveRecord
 
   class EnvironmentMismatchError < ActiveRecordError
     def initialize(current: nil, stored: nil)
-      msg =  "You are attempting to modify a database that was last run in `#{ stored }` environment.\n".dup
+      msg = +"You are attempting to modify a database that was last run in `#{ stored }` environment.\n"
       msg << "You are running in `#{ current }` environment. "
       msg << "If you are sure you want to continue, first set the environment using:\n\n"
       msg << "        rails db:environment:set"
@@ -891,7 +891,7 @@ module ActiveRecord
         source_migrations.each do |migration|
           source = File.binread(migration.filename)
           inserted_comment = "# This migration comes from #{scope} (originally #{migration.version})\n"
-          magic_comments = "".dup
+          magic_comments = +""
           loop do
             # If we have a magic comment in the original migration,
             # insert our comment after the first newline(end of the magic comment line)
@@ -1299,7 +1299,7 @@ module ActiveRecord
           record_version_state_after_migrating(migration.version)
         end
       rescue => e
-        msg = "An error has occurred, ".dup
+        msg = +"An error has occurred, "
         msg << "this and " if use_transaction?(migration)
         msg << "all later migrations canceled:\n\n#{e}"
         raise StandardError, msg, e.backtrace
diff --git a/activerecord/lib/active_record/relation/finder_methods.rb b/activerecord/lib/active_record/relation/finder_methods.rb
index 930e4377ff..6f420fe6bb 100644
--- a/activerecord/lib/active_record/relation/finder_methods.rb
+++ b/activerecord/lib/active_record/relation/finder_methods.rb
@@ -338,14 +338,14 @@ module ActiveRecord
       name = @klass.name
 
       if ids.nil?
-        error = "Couldn't find #{name}".dup
+        error = +"Couldn't find #{name}"
         error << " with#{conditions}" if conditions
         raise RecordNotFound.new(error, name, key)
       elsif Array(ids).size == 1
         error = "Couldn't find #{name} with '#{key}'=#{ids}#{conditions}"
         raise RecordNotFound.new(error, name, key, ids)
       else
-        error = "Couldn't find all #{name.pluralize} with '#{key}': ".dup
+        error = +"Couldn't find all #{name.pluralize} with '#{key}': "
         error << "(#{ids.join(", ")})#{conditions} (found #{result_size} results, but was looking for #{expected_size})."
         error << " Couldn't find #{name.pluralize(not_found_ids.size)} with #{key.to_s.pluralize(not_found_ids.size)} #{not_found_ids.join(', ')}." if not_found_ids
         raise RecordNotFound.new(error, name, key, ids)
diff --git a/activerecord/lib/active_record/tasks/database_tasks.rb b/activerecord/lib/active_record/tasks/database_tasks.rb
index 16e66982e5..5e29085aff 100644
--- a/activerecord/lib/active_record/tasks/database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/database_tasks.rb
@@ -307,7 +307,7 @@ module ActiveRecord
 
       def check_schema_file(filename)
         unless File.exist?(filename)
-          message = %{#{filename} doesn't exist yet. Run `rails db:migrate` to create it, then try again.}.dup
+          message = +%{#{filename} doesn't exist yet. Run `rails db:migrate` to create it, then try again.}
           message << %{ If you do not intend to use a database, you should instead alter #{Rails.root}/config/application.rb to limit the frameworks that will be loaded.} if defined?(::Rails.root)
           Kernel.abort message
         end
diff --git a/activerecord/lib/active_record/tasks/mysql_database_tasks.rb b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
index eddc6fa223..1c1b29b5e1 100644
--- a/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/mysql_database_tasks.rb
@@ -104,7 +104,7 @@ module ActiveRecord
         end
 
         def run_cmd_error(cmd, args, action)
-          msg = "failed to execute: `#{cmd}`\n".dup
+          msg = +"failed to execute: `#{cmd}`\n"
           msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
           msg
         end
diff --git a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
index 029f763158..4da918ada3 100644
--- a/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/postgresql_database_tasks.rb
@@ -115,7 +115,7 @@ module ActiveRecord
         end
 
         def run_cmd_error(cmd, args, action)
-          msg = "failed to execute:\n".dup
+          msg = +"failed to execute:\n"
           msg << "#{cmd} #{args.join(' ')}\n\n"
           msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
           msg
diff --git a/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
index d0bad05176..a82cea80ca 100644
--- a/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
+++ b/activerecord/lib/active_record/tasks/sqlite_database_tasks.rb
@@ -67,7 +67,7 @@ module ActiveRecord
         end
 
         def run_cmd_error(cmd, args)
-          msg = "failed to execute:\n".dup
+          msg = +"failed to execute:\n"
           msg << "#{cmd} #{args.join(' ')}\n\n"
           msg << "Please check the output above for any errors and make sure that `#{cmd}` is installed in your PATH and has proper permissions.\n\n"
           msg
diff --git a/activerecord/lib/arel/collectors/plain_string.rb b/activerecord/lib/arel/collectors/plain_string.rb
index 687d7fbf2f..c0e9fff399 100644
--- a/activerecord/lib/arel/collectors/plain_string.rb
+++ b/activerecord/lib/arel/collectors/plain_string.rb
@@ -4,7 +4,7 @@ module Arel # :nodoc: all
   module Collectors
     class PlainString
       def initialize
-        @str = "".dup
+        @str = +""
       end
 
       def value
diff --git a/activerecord/test/cases/adapter_test.rb b/activerecord/test/cases/adapter_test.rb
index 217ba22294..64c2b51f83 100644
--- a/activerecord/test/cases/adapter_test.rb
+++ b/activerecord/test/cases/adapter_test.rb
@@ -290,7 +290,7 @@ module ActiveRecord
       def test_log_invalid_encoding
         error = assert_raises RuntimeError do
           @connection.send :log, "SELECT 'ы' FROM DUAL" do
-            raise "ы".dup.force_encoding(Encoding::ASCII_8BIT)
+            raise (+"ы").force_encoding(Encoding::ASCII_8BIT)
           end
         end
 
diff --git a/activerecord/test/cases/adapters/postgresql/bytea_test.rb b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
index 64bb6906cd..3988c2adca 100644
--- a/activerecord/test/cases/adapters/postgresql/bytea_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
@@ -49,7 +49,7 @@ class PostgresqlByteaTest < ActiveRecord::PostgreSQLTestCase
   end
 
   def test_type_cast_binary_value
-    data = "\u001F\x8B".dup.force_encoding("BINARY")
+    data = (+"\u001F\x8B").force_encoding("BINARY")
     assert_equal(data, @type.deserialize(data))
   end
 
diff --git a/activerecord/test/cases/adapters/postgresql/money_test.rb b/activerecord/test/cases/adapters/postgresql/money_test.rb
index 61e75e772d..75e5aaed53 100644
--- a/activerecord/test/cases/adapters/postgresql/money_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/money_test.rb
@@ -52,10 +52,10 @@ class PostgresqlMoneyTest < ActiveRecord::PostgreSQLTestCase
 
   def test_money_type_cast
     type = PostgresqlMoney.type_for_attribute("wealth")
-    assert_equal(12345678.12, type.cast("$12,345,678.12".dup))
-    assert_equal(12345678.12, type.cast("$12.345.678,12".dup))
-    assert_equal(-1.15, type.cast("-$1.15".dup))
-    assert_equal(-2.25, type.cast("($2.25)".dup))
+    assert_equal(12345678.12, type.cast(+"$12,345,678.12"))
+    assert_equal(12345678.12, type.cast(+"$12.345.678,12"))
+    assert_equal(-1.15, type.cast(+"-$1.15"))
+    assert_equal(-2.25, type.cast(+"($2.25)"))
   end
 
   def test_schema_dumping
@@ -65,7 +65,7 @@ class PostgresqlMoneyTest < ActiveRecord::PostgreSQLTestCase
   end
 
   def test_create_and_update_money
-    money = PostgresqlMoney.create(wealth: "987.65".dup)
+    money = PostgresqlMoney.create(wealth: +"987.65")
     assert_equal 987.65, money.wealth
 
     new_value = BigDecimal("123.45")
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index 7b73621ed9..70d0a71c53 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -167,7 +167,7 @@ module ActiveRecord
             data binary
           )
         eosql
-        str = "\x80".dup.force_encoding("ASCII-8BIT")
+        str = (+"\x80").force_encoding("ASCII-8BIT")
         binary = DualEncoding.new name: "いただきます！", data: str
         binary.save!
         assert_equal str, binary.data
@@ -176,7 +176,7 @@ module ActiveRecord
       end
 
       def test_type_cast_should_not_mutate_encoding
-        name = "hello".dup.force_encoding(Encoding::ASCII_8BIT)
+        name = (+"hello").force_encoding(Encoding::ASCII_8BIT)
         Owner.create(name: name)
         assert_equal Encoding::ASCII_8BIT, name.encoding
       ensure
diff --git a/activerecord/test/cases/batches_test.rb b/activerecord/test/cases/batches_test.rb
index c8163901c6..da4569e38a 100644
--- a/activerecord/test/cases/batches_test.rb
+++ b/activerecord/test/cases/batches_test.rb
@@ -155,7 +155,7 @@ class EachTest < ActiveRecord::TestCase
   end
 
   def test_find_in_batches_should_not_use_records_after_yielding_them_in_case_original_array_is_modified
-    not_a_post = "not a post".dup
+    not_a_post = +"not a post"
     def not_a_post.id; end
     not_a_post.stub(:id, -> { raise StandardError.new("not_a_post had #id called on it") }) do
       assert_nothing_raised do
@@ -420,7 +420,7 @@ class EachTest < ActiveRecord::TestCase
   end
 
   def test_in_batches_should_not_use_records_after_yielding_them_in_case_original_array_is_modified
-    not_a_post = "not a post".dup
+    not_a_post = +"not a post"
     def not_a_post.id
       raise StandardError.new("not_a_post had #id called on it")
     end
diff --git a/activerecord/test/cases/binary_test.rb b/activerecord/test/cases/binary_test.rb
index d5376ece69..58abdb47f7 100644
--- a/activerecord/test/cases/binary_test.rb
+++ b/activerecord/test/cases/binary_test.rb
@@ -12,7 +12,7 @@ unless current_adapter?(:DB2Adapter)
     FIXTURES = %w(flowers.jpg example.log test.txt)
 
     def test_mixed_encoding
-      str = "\x80".dup
+      str = +"\x80"
       str.force_encoding("ASCII-8BIT")
 
       binary = Binary.new name: "いただきます！", data: str
diff --git a/activerecord/test/cases/core_test.rb b/activerecord/test/cases/core_test.rb
index 6e7ae2efb4..f7fbf3ee8a 100644
--- a/activerecord/test/cases/core_test.rb
+++ b/activerecord/test/cases/core_test.rb
@@ -36,7 +36,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_new
     topic = Topic.new
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = <<~PRETTY
       #<Topic:0xXXXXXX
@@ -65,7 +65,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_persisted
     topic = topics(:first)
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = <<~PRETTY
       #<Topic:0x\\w+
@@ -93,7 +93,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_uninitialized
     topic = Topic.allocate
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = "#<Topic:XXXXXX not initialized>\n"
     assert actual.start_with?(expected.split("XXXXXX").first)
@@ -106,7 +106,7 @@ class CoreTest < ActiveRecord::TestCase
         "inspecting topic"
       end
     end
-    actual = "".dup
+    actual = +""
     PP.pp(subtopic.new, StringIO.new(actual))
     assert_equal "inspecting topic\n", actual
   end
diff --git a/activerecord/test/cases/type/type_map_test.rb b/activerecord/test/cases/type/type_map_test.rb
index f3699c11a2..1ce515a90c 100644
--- a/activerecord/test/cases/type/type_map_test.rb
+++ b/activerecord/test/cases/type/type_map_test.rb
@@ -32,7 +32,7 @@ module ActiveRecord
       end
 
       def test_fuzzy_lookup
-        string = String.new
+        string = +""
         mapping = TypeMap.new
 
         mapping.register_type(/varchar/i, string)
@@ -41,7 +41,7 @@ module ActiveRecord
       end
 
       def test_aliasing_types
-        string = String.new
+        string = +""
         mapping = TypeMap.new
 
         mapping.register_type(/string/i, string)
@@ -73,7 +73,7 @@ module ActiveRecord
       end
 
       def test_register_proc
-        string = String.new
+        string = +""
         binary = Binary.new
         mapping = TypeMap.new
 
diff --git a/activestorage/test/models/filename_test.rb b/activestorage/test/models/filename_test.rb
index 88405e41c0..715116309f 100644
--- a/activestorage/test/models/filename_test.rb
+++ b/activestorage/test/models/filename_test.rb
@@ -30,8 +30,8 @@ class ActiveStorage::FilenameTest < ActiveSupport::TestCase
   end
 
   test "sanitize transcodes to valid UTF-8" do
-    { "\xF6".dup.force_encoding(Encoding::ISO8859_1) => "ö",
-      "\xC3".dup.force_encoding(Encoding::ISO8859_1) => "Ã",
+    { (+"\xF6").force_encoding(Encoding::ISO8859_1) => "ö",
+      (+"\xC3").force_encoding(Encoding::ISO8859_1) => "Ã",
       "\xAD" => "�",
       "\xCF" => "�",
       "\x00" => "",
diff --git a/activestorage/test/service/shared_service_tests.rb b/activestorage/test/service/shared_service_tests.rb
index 58f189af2b..8a8d639af7 100644
--- a/activestorage/test/service/shared_service_tests.rb
+++ b/activestorage/test/service/shared_service_tests.rb
@@ -6,7 +6,7 @@ require "active_support/core_ext/securerandom"
 module ActiveStorage::Service::SharedServiceTests
   extend ActiveSupport::Concern
 
-  FIXTURE_DATA = "\211PNG\r\n\032\n\000\000\000\rIHDR\000\000\000\020\000\000\000\020\001\003\000\000\000%=m\"\000\000\000\006PLTE\000\000\000\377\377\377\245\331\237\335\000\000\0003IDATx\234c\370\377\237\341\377_\206\377\237\031\016\2603\334?\314p\1772\303\315\315\f7\215\031\356\024\203\320\275\317\f\367\201R\314\f\017\300\350\377\177\000Q\206\027(\316]\233P\000\000\000\000IEND\256B`\202".dup.force_encoding(Encoding::BINARY)
+  FIXTURE_DATA = (+"\211PNG\r\n\032\n\000\000\000\rIHDR\000\000\000\020\000\000\000\020\001\003\000\000\000%=m\"\000\000\000\006PLTE\000\000\000\377\377\377\245\331\237\335\000\000\0003IDATx\234c\370\377\237\341\377_\206\377\237\031\016\2603\334?\314p\1772\303\315\315\f7\215\031\356\024\203\320\275\317\f\367\201R\314\f\017\300\350\377\177\000Q\206\027(\316]\233P\000\000\000\000IEND\256B`\202").force_encoding(Encoding::BINARY)
 
   included do
     setup do
diff --git a/activesupport/lib/active_support/duration/iso8601_serializer.rb b/activesupport/lib/active_support/duration/iso8601_serializer.rb
index 84ae29c1ec..0fb0e3f3a5 100644
--- a/activesupport/lib/active_support/duration/iso8601_serializer.rb
+++ b/activesupport/lib/active_support/duration/iso8601_serializer.rb
@@ -16,12 +16,12 @@ module ActiveSupport
         parts, sign = normalize
         return "PT0S".freeze if parts.empty?
 
-        output = "P".dup
+        output = +"P"
         output << "#{parts[:years]}Y"   if parts.key?(:years)
         output << "#{parts[:months]}M"  if parts.key?(:months)
         output << "#{parts[:weeks]}W"   if parts.key?(:weeks)
         output << "#{parts[:days]}D"    if parts.key?(:days)
-        time = "".dup
+        time = +""
         time << "#{parts[:hours]}H"     if parts.key?(:hours)
         time << "#{parts[:minutes]}M"   if parts.key?(:minutes)
         if parts.key?(:seconds)
diff --git a/activesupport/lib/active_support/xml_mini/jdom.rb b/activesupport/lib/active_support/xml_mini/jdom.rb
index 7f94a64016..59c65db2d5 100644
--- a/activesupport/lib/active_support/xml_mini/jdom.rb
+++ b/activesupport/lib/active_support/xml_mini/jdom.rb
@@ -169,7 +169,7 @@ module ActiveSupport
       # element::
       #   XML element to be checked.
       def empty_content?(element)
-        text = "".dup
+        text = +""
         child_nodes = element.child_nodes
         (0...child_nodes.length).each do |i|
           item = child_nodes.item(i)
diff --git a/activesupport/lib/active_support/xml_mini/libxml.rb b/activesupport/lib/active_support/xml_mini/libxml.rb
index 0b000fea60..2a16932f03 100644
--- a/activesupport/lib/active_support/xml_mini/libxml.rb
+++ b/activesupport/lib/active_support/xml_mini/libxml.rb
@@ -55,7 +55,7 @@ module LibXML #:nodoc:
           if c.element?
             c.to_hash(node_hash)
           elsif c.text? || c.cdata?
-            node_hash[CONTENT_ROOT] ||= "".dup
+            node_hash[CONTENT_ROOT] ||= +""
             node_hash[CONTENT_ROOT] << c.content
           end
         end
diff --git a/activesupport/lib/active_support/xml_mini/libxmlsax.rb b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
index dcf16e6084..a22a2c9cb7 100644
--- a/activesupport/lib/active_support/xml_mini/libxmlsax.rb
+++ b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
@@ -23,7 +23,7 @@ module ActiveSupport
       end
 
       def on_start_document
-        @hash = { CONTENT_KEY => "".dup }
+        @hash = { CONTENT_KEY => +"" }
         @hash_stack = [@hash]
       end
 
@@ -33,7 +33,7 @@ module ActiveSupport
       end
 
       def on_start_element(name, attrs = {})
-        new_hash = { CONTENT_KEY => "".dup }.merge!(attrs)
+        new_hash = { CONTENT_KEY => +"" }.merge!(attrs)
         new_hash[HASH_SIZE_KEY] = new_hash.size + 1
 
         case current_hash[name]
diff --git a/activesupport/lib/active_support/xml_mini/nokogiri.rb b/activesupport/lib/active_support/xml_mini/nokogiri.rb
index 5ee6fc8159..4762a759d6 100644
--- a/activesupport/lib/active_support/xml_mini/nokogiri.rb
+++ b/activesupport/lib/active_support/xml_mini/nokogiri.rb
@@ -59,7 +59,7 @@ module ActiveSupport
             if c.element?
               c.to_hash(node_hash)
             elsif c.text? || c.cdata?
-              node_hash[CONTENT_ROOT] ||= "".dup
+              node_hash[CONTENT_ROOT] ||= +""
               node_hash[CONTENT_ROOT] << c.content
             end
           end
diff --git a/activesupport/lib/active_support/xml_mini/nokogirisax.rb b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
index b01ed00a14..0bbb4e258a 100644
--- a/activesupport/lib/active_support/xml_mini/nokogirisax.rb
+++ b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
@@ -39,7 +39,7 @@ module ActiveSupport
       end
 
       def start_element(name, attrs = [])
-        new_hash = { CONTENT_KEY => "".dup }.merge!(Hash[attrs])
+        new_hash = { CONTENT_KEY => +"" }.merge!(Hash[attrs])
         new_hash[HASH_SIZE_KEY] = new_hash.size + 1
 
         case current_hash[name]
diff --git a/activesupport/lib/active_support/xml_mini/rexml.rb b/activesupport/lib/active_support/xml_mini/rexml.rb
index 32458d5b0d..55a155d4ee 100644
--- a/activesupport/lib/active_support/xml_mini/rexml.rb
+++ b/activesupport/lib/active_support/xml_mini/rexml.rb
@@ -76,7 +76,7 @@ module ActiveSupport
           hash
         else
           # must use value to prevent double-escaping
-          texts = "".dup
+          texts = +""
           element.texts.each { |t| texts << t.value }
           merge!(hash, CONTENT_KEY, texts)
         end
diff --git a/activesupport/test/cache/behaviors/cache_store_behavior.rb b/activesupport/test/cache/behaviors/cache_store_behavior.rb
index e17c09ba39..f7c750c08e 100644
--- a/activesupport/test/cache/behaviors/cache_store_behavior.rb
+++ b/activesupport/test/cache/behaviors/cache_store_behavior.rb
@@ -319,7 +319,7 @@ module CacheStoreBehavior
   end
 
   def test_original_store_objects_should_not_be_immutable
-    bar = "bar".dup
+    bar = +"bar"
     @cache.write("foo", bar)
     assert_nothing_raised { bar.gsub!(/.*/, "baz") }
   end
diff --git a/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
index da16142496..842400f4a3 100644
--- a/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
+++ b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
@@ -6,7 +6,7 @@
 module EncodedKeyCacheBehavior
   Encoding.list.each do |encoding|
     define_method "test_#{encoding.name.underscore}_encoded_values" do
-      key = "foo".dup.force_encoding(encoding)
+      key = (+"foo").force_encoding(encoding)
       assert @cache.write(key, "1", raw: true)
       assert_equal "1", @cache.read(key)
       assert_equal "1", @cache.fetch(key)
@@ -18,7 +18,7 @@ module EncodedKeyCacheBehavior
   end
 
   def test_common_utf8_values
-    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    key = (+"\xC3\xBCmlaut").force_encoding(Encoding::UTF_8)
     assert @cache.write(key, "1", raw: true)
     assert_equal "1", @cache.read(key)
     assert_equal "1", @cache.fetch(key)
@@ -29,7 +29,7 @@ module EncodedKeyCacheBehavior
   end
 
   def test_retains_encoding
-    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    key = (+"\xC3\xBCmlaut").force_encoding(Encoding::UTF_8)
     assert @cache.write(key, "1", raw: true)
     assert_equal Encoding::UTF_8, key.encoding
   end
diff --git a/activesupport/test/cache/cache_key_test.rb b/activesupport/test/cache/cache_key_test.rb
index 84e656f504..c2240d03c2 100644
--- a/activesupport/test/cache/cache_key_test.rb
+++ b/activesupport/test/cache/cache_key_test.rb
@@ -47,7 +47,7 @@ class CacheKeyTest < ActiveSupport::TestCase
   end
 
   def test_expand_cache_key_respond_to_cache_key
-    key = "foo".dup
+    key = +"foo"
     def key.cache_key
       :foo_key
     end
@@ -55,7 +55,7 @@ class CacheKeyTest < ActiveSupport::TestCase
   end
 
   def test_expand_cache_key_array_with_something_that_responds_to_cache_key
-    key = "foo".dup
+    key = +"foo"
     def key.cache_key
       :foo_key
     end
diff --git a/activesupport/test/core_ext/object/instance_variables_test.rb b/activesupport/test/core_ext/object/instance_variables_test.rb
index a3d8daab5b..cf1fe5dfa4 100644
--- a/activesupport/test/core_ext/object/instance_variables_test.rb
+++ b/activesupport/test/core_ext/object/instance_variables_test.rb
@@ -19,7 +19,7 @@ class ObjectInstanceVariableTest < ActiveSupport::TestCase
   end
 
   def test_instance_exec_passes_arguments_to_block
-    assert_equal %w(hello goodbye), "hello".dup.instance_exec("goodbye") { |v| [self, v] }
+    assert_equal %w(hello goodbye), (+"hello").instance_exec("goodbye") { |v| [self, v] }
   end
 
   def test_instance_exec_with_frozen_obj
@@ -27,7 +27,7 @@ class ObjectInstanceVariableTest < ActiveSupport::TestCase
   end
 
   def test_instance_exec_nested
-    assert_equal %w(goodbye olleh bar), "hello".dup.instance_exec("goodbye") { |arg|
+    assert_equal %w(goodbye olleh bar), (+"hello").instance_exec("goodbye") { |arg|
       [arg] + instance_exec("bar") { |v| [reverse, v] } }
   end
 end
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
index b8de16cc5e..81299e5b58 100644
--- a/activesupport/test/core_ext/string_ext_test.rb
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -245,8 +245,8 @@ class StringInflectionsTest < ActiveSupport::TestCase
   end
 
   def test_string_squish
-    original = %{\u205f\u3000 A string surrounded by various unicode spaces,
-      with tabs(\t\t), newlines(\n\n), unicode nextlines(\u0085\u0085) and many spaces(  ). \u00a0\u2007}.dup
+    original = +%{\u205f\u3000 A string surrounded by various unicode spaces,
+      with tabs(\t\t), newlines(\n\n), unicode nextlines(\u0085\u0085) and many spaces(  ). \u00a0\u2007}
 
     expected = "A string surrounded by various unicode spaces, " \
       "with tabs( ), newlines( ), unicode nextlines( ) and many spaces( )."
@@ -378,8 +378,8 @@ class StringInflectionsTest < ActiveSupport::TestCase
   end
 
   def test_truncate_multibyte
-    assert_equal "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...".dup.force_encoding(Encoding::UTF_8),
-      "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244".dup.force_encoding(Encoding::UTF_8).truncate(10)
+    assert_equal (+"\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...").force_encoding(Encoding::UTF_8),
+      (+"\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244").force_encoding(Encoding::UTF_8).truncate(10)
   end
 
   def test_truncate_should_not_be_html_safe
@@ -400,7 +400,7 @@ class StringInflectionsTest < ActiveSupport::TestCase
   end
 
   def test_remove!
-    original = "This is a very good day to die".dup
+    original = +"This is a very good day to die"
     assert_equal "This is a good day to die", original.remove!(" very")
     assert_equal "This is a good day to die", original
     assert_equal "This is a good day", original.remove!(" to ", /die/)
@@ -733,7 +733,7 @@ end
 
 class OutputSafetyTest < ActiveSupport::TestCase
   def setup
-    @string = "hello".dup
+    @string = +"hello"
     @object = Class.new(Object) do
       def to_s
         "other"
@@ -809,7 +809,7 @@ class OutputSafetyTest < ActiveSupport::TestCase
   end
 
   test "Concatting safe onto unsafe yields unsafe" do
-    @other_string = "other".dup
+    @other_string = +"other"
 
     string = @string.html_safe
     @other_string.concat(string)
@@ -832,7 +832,7 @@ class OutputSafetyTest < ActiveSupport::TestCase
   end
 
   test "Concatting safe onto unsafe with << yields unsafe" do
-    @other_string = "other".dup
+    @other_string = +"other"
     string = @string.html_safe
 
     @other_string << string
@@ -888,7 +888,7 @@ class OutputSafetyTest < ActiveSupport::TestCase
   test "Concatting an integer to safe always yields safe" do
     string = @string.html_safe
     string = string.concat(13)
-    assert_equal "hello".dup.concat(13), string
+    assert_equal (+"hello").concat(13), string
     assert_predicate string, :html_safe?
   end
 
diff --git a/activesupport/test/logger_test.rb b/activesupport/test/logger_test.rb
index 773b0daa1d..160e1156b6 100644
--- a/activesupport/test/logger_test.rb
+++ b/activesupport/test/logger_test.rb
@@ -40,7 +40,7 @@ class LoggerTest < ActiveSupport::TestCase
     logger = Logger.new f
     logger.level = Logger::DEBUG
 
-    str = "\x80".dup
+    str = +"\x80"
     str.force_encoding("ASCII-8BIT")
 
     logger.add Logger::DEBUG, str
@@ -58,7 +58,7 @@ class LoggerTest < ActiveSupport::TestCase
     logger = Logger.new f
     logger.level = Logger::DEBUG
 
-    str = "\x80".dup
+    str = +"\x80"
     str.force_encoding("ASCII-8BIT")
 
     logger.add Logger::DEBUG, str
diff --git a/activesupport/test/multibyte_chars_test.rb b/activesupport/test/multibyte_chars_test.rb
index 061446c782..11c4822748 100644
--- a/activesupport/test/multibyte_chars_test.rb
+++ b/activesupport/test/multibyte_chars_test.rb
@@ -53,7 +53,7 @@ class MultibyteCharsTest < ActiveSupport::TestCase
   end
 
   def test_forwarded_method_with_non_string_result_should_be_returned_verbatim
-    str = "".dup
+    str = +""
     str.singleton_class.class_eval { def __method_for_multibyte_testing_with_integer_result; 1; end }
     @chars.wrapped_string.singleton_class.class_eval { def __method_for_multibyte_testing_with_integer_result; 1; end }
 
@@ -61,14 +61,14 @@ class MultibyteCharsTest < ActiveSupport::TestCase
   end
 
   def test_should_concatenate
-    mb_a = "a".dup.mb_chars
-    mb_b = "b".dup.mb_chars
+    mb_a = (+"a").mb_chars
+    mb_b = (+"b").mb_chars
     assert_equal "ab", mb_a + "b"
     assert_equal "ab", "a" + mb_b
     assert_equal "ab", mb_a + mb_b
 
     assert_equal "ab", mb_a << "b"
-    assert_equal "ab", "a".dup << mb_b
+    assert_equal "ab", (+"a") << mb_b
     assert_equal "abb", mb_a << mb_b
   end
 
@@ -80,7 +80,7 @@ class MultibyteCharsTest < ActiveSupport::TestCase
 
   def test_concatenation_should_return_a_proxy_class_instance
     assert_equal ActiveSupport::Multibyte.proxy_class, ("a".mb_chars + "b").class
-    assert_equal ActiveSupport::Multibyte.proxy_class, ("a".dup.mb_chars << "b").class
+    assert_equal ActiveSupport::Multibyte.proxy_class, ((+"a").mb_chars << "b").class
   end
 
   def test_ascii_strings_are_treated_at_utf8_strings
@@ -90,8 +90,8 @@ class MultibyteCharsTest < ActiveSupport::TestCase
   def test_concatenate_should_return_proxy_instance
     assert(("a".mb_chars + "b").kind_of?(@proxy_class))
     assert(("a".mb_chars + "b".mb_chars).kind_of?(@proxy_class))
-    assert(("a".dup.mb_chars << "b").kind_of?(@proxy_class))
-    assert(("a".dup.mb_chars << "b".mb_chars).kind_of?(@proxy_class))
+    assert(((+"a").mb_chars << "b").kind_of?(@proxy_class))
+    assert(((+"a").mb_chars << "b".mb_chars).kind_of?(@proxy_class))
   end
 
   def test_should_return_string_as_json
@@ -135,7 +135,7 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_tidy_bytes_bang_should_change_wrapped_string
-    original = " Un bUen café \x92".dup
+    original = +" Un bUen café \x92"
     proxy = chars(original.dup)
     proxy.tidy_bytes!
     assert_not_equal original, proxy.to_s
@@ -152,7 +152,7 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_string_methods_are_chainable
-    assert chars("".dup).insert(0, "").kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars(+"").insert(0, "").kind_of?(ActiveSupport::Multibyte.proxy_class)
     assert chars("").rjust(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
     assert chars("").ljust(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
     assert chars("").center(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
@@ -197,7 +197,7 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_should_use_character_offsets_for_insert_offsets
-    assert_equal "", "".dup.mb_chars.insert(0, "")
+    assert_equal "", (+"").mb_chars.insert(0, "")
     assert_equal "こわにちわ", @chars.insert(1, "わ")
     assert_equal "こわわわにちわ", @chars.insert(2, "わわ")
     assert_equal "わこわわわにちわ", @chars.insert(0, "わ")
@@ -420,13 +420,13 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_slice_bang_removes_the_slice_from_the_receiver
-    chars = "úüù".dup.mb_chars
+    chars = (+"úüù").mb_chars
     chars.slice!(0, 2)
     assert_equal "ù", chars
   end
 
   def test_slice_bang_returns_nil_and_does_not_modify_receiver_if_out_of_bounds
-    string = "úüù".dup
+    string = +"úüù"
     chars = string.mb_chars
     assert_nil chars.slice!(4, 5)
     assert_equal "úüù", chars
diff --git a/activesupport/test/multibyte_test_helpers.rb b/activesupport/test/multibyte_test_helpers.rb
index 98f36aa939..d97ce6727a 100644
--- a/activesupport/test/multibyte_test_helpers.rb
+++ b/activesupport/test/multibyte_test_helpers.rb
@@ -29,7 +29,7 @@ module MultibyteTestHelpers
 
   UNICODE_STRING = "こにちわ".freeze
   ASCII_STRING = "ohayo".freeze
-  BYTE_STRING = "\270\236\010\210\245".dup.force_encoding("ASCII-8BIT").freeze
+  BYTE_STRING = (+"\270\236\010\210\245").force_encoding("ASCII-8BIT").freeze
 
   def chars(str)
     ActiveSupport::Multibyte::Chars.new(str)
diff --git a/railties/lib/rails/commands/dbconsole/dbconsole_command.rb b/railties/lib/rails/commands/dbconsole/dbconsole_command.rb
index 806b7de6d6..0fac7d34a0 100644
--- a/railties/lib/rails/commands/dbconsole/dbconsole_command.rb
+++ b/railties/lib/rails/commands/dbconsole/dbconsole_command.rb
@@ -75,7 +75,7 @@ module Rails
         args += ["-P", "#{config['password']}"] if config["password"]
 
         if config["host"]
-          host_arg = "#{config['host']}".dup
+          host_arg = +"#{config['host']}"
           host_arg << ":#{config['port']}" if config["port"]
           args += ["-S", host_arg]
         end
diff --git a/railties/lib/rails/generators/generated_attribute.rb b/railties/lib/rails/generators/generated_attribute.rb
index f7fd30a5fb..3f20f5a718 100644
--- a/railties/lib/rails/generators/generated_attribute.rb
+++ b/railties/lib/rails/generators/generated_attribute.rb
@@ -153,7 +153,7 @@ module Rails
       end
 
       def inject_options
-        "".dup.tap { |s| options_for_migration.each { |k, v| s << ", #{k}: #{v.inspect}" } }
+        (+"").tap { |s| options_for_migration.each { |k, v| s << ", #{k}: #{v.inspect}" } }
       end
 
       def inject_index_options
diff --git a/railties/lib/rails/info.rb b/railties/lib/rails/info.rb
index d5c9973c6b..3df36efc4c 100644
--- a/railties/lib/rails/info.rb
+++ b/railties/lib/rails/info.rb
@@ -41,7 +41,7 @@ module Rails
       alias inspect to_s
 
       def to_html
-        "<table>".dup.tap do |table|
+        (+"<table>").tap do |table|
           properties.each do |(name, value)|
             table << %(<tr><td class="name">#{CGI.escapeHTML(name.to_s)}</td>)
             formatted_value = if value.kind_of?(Array)
diff --git a/railties/lib/rails/source_annotation_extractor.rb b/railties/lib/rails/source_annotation_extractor.rb
index 2d66a4dc7d..d7170e6282 100644
--- a/railties/lib/rails/source_annotation_extractor.rb
+++ b/railties/lib/rails/source_annotation_extractor.rb
@@ -50,7 +50,7 @@ module Rails
       # If +options+ has a flag <tt>:tag</tt> the tag is shown as in the example above.
       # Otherwise the string contains just line and text.
       def to_s(options = {})
-        s = "[#{line.to_s.rjust(options[:indent])}] ".dup
+        s = +"[#{line.to_s.rjust(options[:indent])}] "
         s << "[#{tag}] " if options[:tag]
         s << text
       end
diff --git a/railties/test/console_helpers.rb b/railties/test/console_helpers.rb
index 8350fce5ee..67f55fdc45 100644
--- a/railties/test/console_helpers.rb
+++ b/railties/test/console_helpers.rb
@@ -9,7 +9,7 @@ module ConsoleHelpers
   def assert_output(expected, io, timeout = 10)
     timeout = Time.now + timeout
 
-    output = "".dup
+    output = +""
     until output.include?(expected) || Time.now > timeout
       if IO.select([io], [], [], 0.1)
         output << io.read(1)
diff --git a/railties/test/generators/app_generator_test.rb b/railties/test/generators/app_generator_test.rb
index 14cdd8b5c9..1169633244 100644
--- a/railties/test/generators/app_generator_test.rb
+++ b/railties/test/generators/app_generator_test.rb
@@ -964,7 +964,7 @@ class AppGeneratorTest < Rails::Generators::TestCase
 
   def test_after_bundle_callback
     path = "http://example.org/rails_template"
-    template = %{ after_bundle { run 'echo ran after_bundle' } }.dup
+    template = +%{ after_bundle { run 'echo ran after_bundle' } }
     template.instance_eval "def read; self; end" # Make the string respond to read
 
     check_open = -> *args do
diff --git a/railties/test/generators/plugin_generator_test.rb b/railties/test/generators/plugin_generator_test.rb
index 20acd23329..468a9c9e89 100644
--- a/railties/test/generators/plugin_generator_test.rb
+++ b/railties/test/generators/plugin_generator_test.rb
@@ -737,7 +737,7 @@ class PluginGeneratorTest < Rails::Generators::TestCase
 
   def test_after_bundle_callback
     path = "http://example.org/rails_template"
-    template = %{ after_bundle { run "echo ran after_bundle" } }.dup
+    template = +%{ after_bundle { run "echo ran after_bundle" } }
     template.instance_eval "def read; self; end" # Make the string respond to read
 
     check_open = -> *args do
diff --git a/railties/test/generators/shared_generator_tests.rb b/railties/test/generators/shared_generator_tests.rb
index aa577e4234..5a1257e5c1 100644
--- a/railties/test/generators/shared_generator_tests.rb
+++ b/railties/test/generators/shared_generator_tests.rb
@@ -83,7 +83,7 @@ module SharedGeneratorTests
 
   def test_template_is_executed_when_supplied_an_https_path
     path = "https://gist.github.com/josevalim/103208/raw/"
-    template = %{ say "It works!" }.dup
+    template = +%{ say "It works!" }
     template.instance_eval "def read; self; end" # Make the string respond to read
 
     check_open = -> *args do
diff --git a/railties/test/isolation/abstract_unit.rb b/railties/test/isolation/abstract_unit.rb
index 96d21b3ae2..2a8c6d8f97 100644
--- a/railties/test/isolation/abstract_unit.rb
+++ b/railties/test/isolation/abstract_unit.rb
@@ -71,7 +71,7 @@ module TestHelpers
     end
 
     def extract_body(response)
-      "".dup.tap do |body|
+      (+"").tap do |body|
         response[2].each { |chunk| body << chunk }
       end
     end