diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index e3ad3f9ba7..7947e9d393 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -603,12 +603,9 @@ module ActionDispatch
 
           options[:constraints] ||= {}
           unless options[:constraints].is_a?(Hash)
-            options[:blocks]      = options[:constraints]
-            options[:constraints] = {}
+            block, options[:constraints] = options[:constraints], {}
           end
 
-          options[:options] = options
-
           scope_options.each do |option|
             if value = options.delete(option)
               recover[option] = @scope[option]
@@ -616,12 +613,21 @@ module ActionDispatch
             end
           end
 
+          recover[:block] = @scope[:blocks]
+          @scope[:blocks] = merge_blocks_scope(@scope[:blocks], block)
+
+          recover[:options] = @scope[:options]
+          @scope[:options]  = merge_options_scope(@scope[:options], options)
+
           yield
           self
         ensure
           scope_options.each do |option|
             @scope[option] = recover[option] if recover.has_key?(option)
           end
+
+          @scope[:options] = recover[:options]
+          @scope[:blocks]  = recover[:block]
         end
 
         # Scopes routes to a specific controller