3 files changed, 10 insertions, 3 deletions
diff --git a/actionpack/lib/action_view/helpers/form_helper.rb b/actionpack/lib/action_view/helpers/form_helper.rb
index 3dae1fc87a..6b6a7edc1d 100644
--- a/actionpack/lib/action_view/helpers/form_helper.rb
+++ b/actionpack/lib/action_view/helpers/form_helper.rb
@@ -433,7 +433,7 @@ module ActionView
 
         builder = instantiate_builder(object_name, object, options)
         output  = capture(builder, &block)
-        html_options[:multipart] = builder.multipart?
+        html_options[:multipart] ||= builder.multipart?
 
         form_tag(options[:url] || {}, html_options) { output }
       end
diff --git a/actionpack/lib/action_view/lookup_context.rb b/actionpack/lib/action_view/lookup_context.rb
index 4e4816d983..d61cc0f304 100644
--- a/actionpack/lib/action_view/lookup_context.rb
+++ b/actionpack/lib/action_view/lookup_context.rb
@@ -43,7 +43,13 @@ module ActionView
     module Accessors #:nodoc:
     end
 
-    register_detail(:locale)  { [I18n.locale, I18n.default_locale].uniq }
+    register_detail(:locale) do
+      locales = [I18n.locale]
+      locales.concat(I18n.fallbacks[I18n.locale]) if I18n.respond_to? :fallbacks
+      locales << I18n.default_locale
+      locales.uniq!
+      locales
+    end
     register_detail(:formats) { ActionView::Base.default_formats || [:html, :text, :js, :css,  :xml, :json] }
     register_detail(:handlers){ Template::Handlers.extensions }
 
diff --git a/actionpack/lib/action_view/template.rb b/actionpack/lib/action_view/template.rb
index 720890eeb9..946db1df79 100644
--- a/actionpack/lib/action_view/template.rb
+++ b/actionpack/lib/action_view/template.rb
@@ -324,7 +324,8 @@ module ActionView
       end
 
       def locals_code #:nodoc:
-        @locals.map { |key| "#{key} = local_assigns[:#{key}];" }.join
+        # Double assign to suppress the dreaded 'assigned but unused variable' warning
+        @locals.map { |key| "#{key} = #{key} = local_assigns[:#{key}];" }.join
       end
 
       def method_name #:nodoc: