diff --git a/actionpack/lib/action_dispatch/routing/inspector.rb b/actionpack/lib/action_dispatch/routing/inspector.rb
index 2135b280dae589f6317c6fae3683ac92bd872210..4be49516bf4f3f0ce5fb4a844a21c8c2e6752b51 100644
--- a/actionpack/lib/action_dispatch/routing/inspector.rb
+++ b/actionpack/lib/action_dispatch/routing/inspector.rb
@@ -14,10 +14,10 @@ def constraints
 
       def rack_app(app = self.app)
         @rack_app ||= begin
+          app = app.app
           class_name = app.class.name.to_s
-          if class_name == "ActionDispatch::Routing::Mapper::Constraints"
-            app.app
-          elsif ActionDispatch::Routing::Redirect === app || class_name !~ /^ActionDispatch::Routing/
+
+          if ActionDispatch::Routing::Redirect === app || class_name !~ /^ActionDispatch::Routing/
             app
           end
         end
diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index b33c5e0dfd855a7784a0225435957022f941d597..c5e093dae5dcd694c13c7dab5a2d21c37b4da027 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -216,10 +216,12 @@ def normalize_conditions!
           end
 
           def app
+            endpoint = to.respond_to?(:call) ? to : dispatcher
+
             if blocks.any?
               Constraints.new(endpoint, blocks, @set.request_class)
             else
-              endpoint
+              Constraints.new(endpoint, blocks, @set.request_class)
             end
           end
 
@@ -306,10 +308,6 @@ def strexp
             Journey::Router::Strexp.compile(path, requirements, SEPARATORS)
           end
 
-          def endpoint
-            to.respond_to?(:call) ? to : dispatcher
-          end
-
           def dispatcher
             Routing::RouteSet::Dispatcher.new(defaults)
           end
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 924455bce22eeb2ed9c842b4bc9884dc4b0999f2..f36453020f63d47f72af6d3644678d3b36d999c7 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -704,7 +704,7 @@ def recognize_path(path, environment = {})
           old_params = req.path_parameters
           req.path_parameters = old_params.merge params
           dispatcher = route.app
-          if dispatcher.is_a?(Mapper::Constraints) && dispatcher.matches?(env)
+          if dispatcher.matches?(env)
             dispatcher = dispatcher.app
           end
 
diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index a427113763d92742e6aefe491667f89d60a6243d..51b5e9cf0757057a6485f04e9c05b162896147d5 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -3389,6 +3389,9 @@ def ip
     def x_header
       @env["HTTP_X_HEADER"] || ""
     end
+
+    def reset_parameters
+    end
   end
 
   class XHeader