reuse path formatter from the non-optimized path.

The optimized and non-optimized path share more code now without
significant performance degretation

actionpack/lib/action_dispatch/journey/route.rb

@@ -76,10 +76,6 @@ def format(path_options)
         @path_formatter.evaluate path_options
       end
 
-      def optimized_path
-        Visitors::OptimizedPath.new.accept(path.spec)
-      end
-
       def optional_parts
         path.optional_names.map { |n| n.to_sym }
       end

actionpack/lib/action_dispatch/journey/visitors.rb

@@ -38,7 +38,8 @@ def evaluate(hash)
 
         @parameters.each do |index|
           param = parts[index]
-          value = hash.fetch(param.name) { return ''.freeze }
+          value = hash[param.name]
+          return ''.freeze unless value
           parts[index] = param.escape value
         end
 
@@ -149,34 +150,6 @@ def visit_GROUP(node)
         end
       end
 
-      class OptimizedPath < Visitor # :nodoc:
-        def accept(node)
-          Array(visit(node))
-        end
-
-        private
-
-          def visit_CAT(node)
-            [visit(node.left), visit(node.right)].flatten
-          end
-
-          def visit_SYMBOL(node)
-            node.left[1..-1].to_sym
-          end
-
-          def visit_STAR(node)
-            visit(node.left)
-          end
-
-          def visit_GROUP(node)
-            []
-          end
-
-          %w{ LITERAL SLASH DOT }.each do |t|
-            class_eval %{ def visit_#{t}(n); n.left; end }, __FILE__, __LINE__
-          end
-      end
-
       class Dot < Visitor # :nodoc:
         def initialize
           @nodes = []

actionpack/lib/action_dispatch/routing/route_set.rb

@@ -168,7 +168,6 @@ def initialize(route, options)
               @klass          = Journey::Router::Utils
               @required_parts = @route.required_parts
               @arg_size       = @required_parts.size
-              @optimized_path = @route.optimized_path
             end
 
             def call(t, args)
@@ -191,11 +190,7 @@ def optimized_helper(args)
                 raise_generation_error(params, missing_keys)
               end
 
-              @optimized_path.map{ |segment| replace_segment(params, segment) }.join
-            end
-
-            def replace_segment(params, segment)
-              Symbol === segment ? @klass.escape_segment(params[segment]) : segment
+              @route.format params
             end
 
             def optimize_routes_generation?(t)