moving visitor logic to the visitor

lib/arel/select_manager.rb

@@ -44,9 +44,7 @@ def take limit
 
     def join_sql
       viz = Visitors::JoinSql.new @engine
-      Nodes::SqlLiteral.new(
-        @ctx.froms.grep(Nodes::Join).map { |x| viz.accept x }.join ', '
-      )
+      Nodes::SqlLiteral.new viz.accept @ctx
     end
 
     def joins manager

lib/arel/visitors/join_sql.rb

@@ -9,6 +9,10 @@ module Visitors
     # This visitor is used in SelectManager#join_sql and is for backwards
     # compatibility with Arel V1.0
     class JoinSql < Arel::Visitors::ToSql
+      def visit_Arel_Nodes_SelectCore o
+        o.froms.grep(Nodes::Join).map { |x| visit x }.join ', '
+      end
+
       def visit_Arel_Nodes_OuterJoin o
         "OUTER JOIN #{visit o.right} #{visit o.constraint}"
       end