3 files changed, 9 insertions, 6 deletions
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index f2c9e7b1a0..34b5b48f3a 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -1504,7 +1504,7 @@ module ActionDispatch
         end
 
         def using_match_shorthand?(path, options)
-          path && (options[:to] || options[:action]).nil? && path =~ %r{/[\w/]+$}
+          path && (options[:to] || options[:action]).nil? && path =~ %r{^/?[-\w]+/[-\w/]+$}
         end
 
         def decomposed_match(path, options) # :nodoc:
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 65d6a5eb1e..ce04f0b08a 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -395,9 +395,11 @@ module ActionDispatch
         return if MountedHelpers.method_defined?(name)
 
         routes = self
+        helpers = routes.url_helpers
+
         MountedHelpers.class_eval do
           define_method "_#{name}" do
-            RoutesProxy.new(routes, _routes_context)
+            RoutesProxy.new(routes, _routes_context, helpers)
           end
         end
 
diff --git a/actionpack/lib/action_dispatch/routing/routes_proxy.rb b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
index e2393d3799..040ea04046 100644
--- a/actionpack/lib/action_dispatch/routing/routes_proxy.rb
+++ b/actionpack/lib/action_dispatch/routing/routes_proxy.rb
@@ -8,8 +8,9 @@ module ActionDispatch
       attr_accessor :scope, :routes
       alias :_routes :routes
 
-      def initialize(routes, scope)
+      def initialize(routes, scope, helpers)
         @routes, @scope = routes, scope
+        @helpers = helpers
       end
 
       def url_options
@@ -19,16 +20,16 @@ module ActionDispatch
       end
 
       def respond_to?(method, include_private = false)
-        super || routes.url_helpers.respond_to?(method)
+        super || @helpers.respond_to?(method)
       end
 
       def method_missing(method, *args)
-        if routes.url_helpers.respond_to?(method)
+        if @helpers.respond_to?(method)
           self.class.class_eval <<-RUBY, __FILE__, __LINE__ + 1
             def #{method}(*args)
               options = args.extract_options!
               args << url_options.merge((options || {}).symbolize_keys)
-              routes.url_helpers.#{method}(*args)
+              @helpers.#{method}(*args)
             end
           RUBY
           send(method, *args)