diff --git a/lib/vagrant/action/builtin/mixin_synced_folders.rb b/lib/vagrant/action/builtin/mixin_synced_folders.rb
index 81c238fc8..f505d2241 100644
--- a/lib/vagrant/action/builtin/mixin_synced_folders.rb
+++ b/lib/vagrant/action/builtin/mixin_synced_folders.rb
@@ -98,7 +98,8 @@ module Vagrant
             end
           end
 
-          folder_data = JSON.dump(folders)
+          # Remove implementation instances
+          folder_data = JSON.dump(folders.to_h)
 
           # Scrub any register credentials from the synced folders
           # configuration data to prevent accidental leakage
@@ -125,7 +126,7 @@ module Vagrant
           end
 
           config_folders = config.synced_folders
-          folders = Vagrant::Util::TypedHash.new()
+          folders = Vagrant::Plugin::V2::SyncedFolder::Collection.new
 
           # Determine all the synced folders as well as the implementation
           # they're going to use.
@@ -182,8 +183,10 @@ module Vagrant
 
           # Apply the scoped hash overrides to get the options
           folders.dup.each do |impl_name, fs|
+            impl = plugins[impl_name].first.new._initialize(machine, impl_name)
             new_fs = {}
             fs.each do |id, data|
+              data[:plugin] = impl
               id         = data[:id] if data[:id]
               new_fs[id] = scoped_hash_override(data, impl_name)
             end
@@ -191,12 +194,7 @@ module Vagrant
             folders[impl_name] = new_fs
           end
 
-          folders.types = folders.map { |type, folders|
-            impl = plugins[type][0].new()
-            impl._initialize(machine, type)
-            [type, impl]
-          }.to_h 
-          return folders
+          folders
         end
 
         # This finds the difference between two lists of synced folder
@@ -245,32 +243,26 @@ module Vagrant
         protected
 
         def cached_synced_folders(machine)
-          folders = JSON.parse(machine.data_dir.join("synced_folders").read, object_class: Vagrant::Util::TypedHash).tap do |r|
-            # We have to do all sorts of things to make the proper things
-            # symbols and
-            r.keys.each do |k|
-              r[k].each do |ik, v|
-                v.keys.each do |vk|
-                  v[vk.to_sym] = v[vk]
-                  v.delete(vk)
-                end
-              end
-
-              r[k.to_sym] = r[k]
-              r.delete(k)
-            end
+          import = JSON.parse(machine.data_dir.join("synced_folders").read)
+          import.each do |type, folders|
+            impl = plugins[type.to_sym].first.new._initialize(machine, type)
+            folders.each { |_, v| v[:plugin] = impl }
           end
-          folders.types = folders.map { |type, folders|
-            impl = plugins[type][0].new()
-            impl._initialize(machine, type)
-            [type, impl]
-          }.to_h || {}
-          folders
+          # Symbolize the keys we want as symbols
+          import.keys.dup.each do |k|
+            import[k].values.each do |item|
+              item.keys.dup.each do |ik|
+                item[ik.to_sym] = item.delete(ik)
+              end
+            end
+            import[k.to_sym] = import.delete(k)
+          end
+          Vagrant::Plugin::V2::SyncedFolder::Collection[import]
         rescue Errno::ENOENT
           # If the file doesn't exist, we probably just have a machine created
           # by a version of Vagrant that didn't cache shared folders. Report no
           # shared folders to be safe.
-          Vagrant::Util::TypedHash.new(types: {})
+          Vagrant::Plugin::V2::SyncedFolder::Collection.new
         end
       end
     end
diff --git a/lib/vagrant/plugin/v2/synced_folder.rb b/lib/vagrant/plugin/v2/synced_folder.rb
index 06b4ec623..851b1ea05 100644
--- a/lib/vagrant/plugin/v2/synced_folder.rb
+++ b/lib/vagrant/plugin/v2/synced_folder.rb
@@ -3,6 +3,45 @@ module Vagrant
     module V2
       # This is the base class for a synced folder implementation.
       class SyncedFolder
+        class Collection < Hash
+
+          # @return [Array<Symbol>] names of synced folder types
+          def types
+            keys
+          end
+
+          # Fetch the synced plugin folder of the given type
+          #
+          # @param [Symbol] t Synced folder type
+          # @return [Vagrant::Plugin::V2::SyncedFolder]
+          def type(t)
+            f = detect { |k, _| k.to_sym == t.to_sym }.last
+            raise KeyError, "Unknown synced folder type" if !f
+            f.values.first[:plugin]
+          end
+
+          # Converts to a regular Hash and removes
+          # plugin instances so the result is ready
+          # for serialization
+          #
+          # @return [Hash]
+          def to_h
+            c = lambda do |h|
+              h.keys.each do |k|
+                if h[k].is_a?(Hash)
+                  h[k] = c.call(h[k].to_h)
+                end
+              end
+              h
+            end
+            h = c.call(super)
+            h.values.each do |f|
+              f.delete(:plugin)
+            end
+            h
+          end
+        end
+
         include CapabilityHost
 
         # This is called early when the synced folder is set to determine
@@ -61,6 +100,7 @@ module Vagrant
           plugins = Vagrant.plugin("2").manager.synced_folders
           capabilities = Vagrant.plugin("2").manager.synced_folder_capabilities
           initialize_capabilities!(synced_folder_type, plugins, capabilities, machine)
+          self
         end
       end
     end
diff --git a/plugins/guests/linux/cap/mount_virtualbox_shared_folder.rb b/plugins/guests/linux/cap/mount_virtualbox_shared_folder.rb
index abbf917d2..0d788a306 100644
--- a/plugins/guests/linux/cap/mount_virtualbox_shared_folder.rb
+++ b/plugins/guests/linux/cap/mount_virtualbox_shared_folder.rb
@@ -8,14 +8,14 @@ module VagrantPlugins
 
         def self.mount_virtualbox_shared_folder(machine, name, guestpath, options)
           guest_path = Shellwords.escape(guestpath)
-          mount_type = machine.synced_folders.types[:virtualbox].capability(:mount_type)
+          mount_type = options[:plugin].capability(:mount_type)
 
           @@logger.debug("Mounting #{name} (#{options[:hostpath]} to #{guestpath})")
 
           builtin_mount_type = "-cit #{mount_type}"
           addon_mount_type = "-t #{mount_type}"
 
-          mount_options, mount_uid, mount_gid = machine.synced_folders.types[:virtualbox].capability(:mount_options, name, guest_path, options)
+          mount_options, mount_uid, mount_gid = options[:plugin].capability(:mount_options, name, guest_path, options)
           mount_command = "mount #{addon_mount_type} -o #{mount_options} #{name} #{guest_path}"
 
           # Create the guest path if it doesn't exist
diff --git a/plugins/guests/linux/cap/persist_mount_shared_folder.rb b/plugins/guests/linux/cap/persist_mount_shared_folder.rb
index 78f187b86..c2f7c3cc5 100644
--- a/plugins/guests/linux/cap/persist_mount_shared_folder.rb
+++ b/plugins/guests/linux/cap/persist_mount_shared_folder.rb
@@ -10,8 +10,8 @@ module VagrantPlugins
 
         # Inserts fstab entry for a set of synced folders. Will fully replace
         # the currently managed group of Vagrant managed entries. Note, passing
-        # empty list of folders will just remove entries      
-        # 
+        # empty list of folders will just remove entries
+        #
         # @param [Machine] machine The machine to run the action on
         # @param [Map<String, Map>] A map of folders to add to fstab
         def self.persist_mount_shared_folder(machine, folders)
@@ -20,15 +20,15 @@ module VagrantPlugins
             return
           end
 
-          ssh_info = machine.ssh_info          
+          ssh_info = machine.ssh_info
           export_folders = folders.map { |type, folder|
             folder.map { |name, data|
               data[:owner] ||= ssh_info[:username]
               data[:group] ||= ssh_info[:username]
               guest_path = Shellwords.escape(data[:guestpath])
-              mount_options, _, _ = machine.synced_folders.types[type].capability(
+              mount_options, _, _ = data[:plugin].capability(
                 :mount_options, name, guest_path, data)
-              mount_type = machine.synced_folders.types[type].capability(:mount_type)
+              mount_type = data[:plugin].capability(:mount_type)
               mount_options = "#{mount_options},nofail"
               {
                 name: name,
diff --git a/plugins/kernel_v2/config/vm.rb b/plugins/kernel_v2/config/vm.rb
index 6415f58a8..4d64aace6 100644
--- a/plugins/kernel_v2/config/vm.rb
+++ b/plugins/kernel_v2/config/vm.rb
@@ -727,7 +727,8 @@ module VagrantPlugins
 
         if @allow_fstab_modification == UNSET_VALUE
           plugins = Vagrant.plugin("2").manager.synced_folders
-          machine.synced_folders.types.each do |_, inst|
+          machine.synced_folders.types.each do |impl_name|
+            inst = machine.synced_folders.type(impl_name)
             if inst.capability?(:default_fstab_modification)
               if inst.capability(:default_fstab_modification) == false
                 @allow_fstab_modification = false
diff --git a/test/unit/plugins/guests/linux/cap/mount_virtual_box_shared_folder_test.rb b/test/unit/plugins/guests/linux/cap/mount_virtual_box_shared_folder_test.rb
index 3e8662f78..4ace19225 100644
--- a/test/unit/plugins/guests/linux/cap/mount_virtual_box_shared_folder_test.rb
+++ b/test/unit/plugins/guests/linux/cap/mount_virtual_box_shared_folder_test.rb
@@ -16,18 +16,20 @@ describe "VagrantPlugins::GuestLinux::Cap::MountVirtualBoxSharedFolder" do
   let(:mount_name){ "vagrant" }
   let(:mount_guest_path){ "/vagrant" }
   let(:folder_options) do
-    {
-      owner: mount_owner,
-      group: mount_group,
-      hostpath: "/host/directory/path"
-    }
+    Vagrant::Plugin::V2::SyncedFolder::Collection[
+      {
+        owner: mount_owner,
+        group: mount_group,
+        hostpath: "/host/directory/path",
+        plugin: folder_plugin
+      }
+    ]
   end
   let(:cap){ caps.get(:mount_virtualbox_shared_folder) }
-  let(:mount_options_cap){ double("opts") }
+  let(:folder_plugin) { double("folder_plugin") }
 
   before do
     allow(machine).to receive(:communicate).and_return(comm)
-    allow(machine).to receive_message_chain(:synced_folders, :types).and_return( { :virtualbox => mount_options_cap } )
   end
 
   after do
@@ -42,17 +44,21 @@ describe "VagrantPlugins::GuestLinux::Cap::MountVirtualBoxSharedFolder" do
     end
 
     it "generates the expected default mount command" do
-      expect(mount_options_cap).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
-      expect(mount_options_cap).to receive(:capability).with(:mount_type).and_return("vboxsf")
+      expect(folder_plugin).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).
+        and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
+      expect(folder_plugin).to receive(:capability).with(:mount_type).and_return("vboxsf")
       expect(comm).to receive(:sudo).with("mount -t vboxsf -o uid=#{mount_uid},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
+
       cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
     end
 
     it "automatically chown's the mounted directory on guest" do
-      expect(mount_options_cap).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
-      expect(mount_options_cap).to receive(:capability).with(:mount_type).and_return("vboxsf")
+      expect(folder_plugin).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).
+        and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
+      expect(folder_plugin).to receive(:capability).with(:mount_type).and_return("vboxsf")
       expect(comm).to receive(:sudo).with("mount -t vboxsf -o uid=#{mount_uid},gid=#{mount_gid} #{mount_name} #{mount_guest_path}", anything)
       expect(comm).to receive(:sudo).with("chown #{mount_uid}:#{mount_gid} #{mount_guest_path}")
+
       cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
     end
 
@@ -60,8 +66,10 @@ describe "VagrantPlugins::GuestLinux::Cap::MountVirtualBoxSharedFolder" do
 
       it "emits mount event" do
         expect(comm).to receive(:sudo).with(/initctl emit/)
-        expect(mount_options_cap).to receive(:capability).with(:mount_type).and_return("vboxsf")
-        expect(mount_options_cap).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
+        expect(folder_plugin).to receive(:capability).with(:mount_type).and_return("vboxsf")
+        expect(folder_plugin).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).
+          and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
+
         cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
       end
     end
@@ -74,10 +82,12 @@ mount.vboxsf cannot be used with mainline vboxsf; instead use:
 EOF
       }
       it "should perform guest mount using builtin module" do
-        expect(mount_options_cap).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
-        expect(mount_options_cap).to receive(:capability).with(:mount_type).and_return("vboxsf")
+        expect(folder_plugin).to receive(:capability).with(:mount_options, mount_name, mount_guest_path, folder_options).
+          and_return(["uid=#{mount_uid},gid=#{mount_gid}", mount_uid, mount_gid])
+        expect(folder_plugin).to receive(:capability).with(:mount_type).and_return("vboxsf")
         expect(comm).to receive(:sudo).with(/mount -t vboxsf/, any_args).and_yield(:stderr, vbox_stderr).and_return(1)
         expect(comm).to receive(:sudo).with(/mount -cit/, any_args)
+
         cap.mount_virtualbox_shared_folder(machine, mount_name, mount_guest_path, folder_options)
       end
     end
diff --git a/test/unit/plugins/guests/linux/cap/persist_mount_shared_folder_test.rb b/test/unit/plugins/guests/linux/cap/persist_mount_shared_folder_test.rb
index 030134529..f7ae6b51b 100644
--- a/test/unit/plugins/guests/linux/cap/persist_mount_shared_folder_test.rb
+++ b/test/unit/plugins/guests/linux/cap/persist_mount_shared_folder_test.rb
@@ -12,14 +12,20 @@ describe "VagrantPlugins::GuestLinux::Cap::PersistMountSharedFolder" do
   let(:options_gid){ '1234' }
   let(:options_uid){ '1234' }
   let(:cap){ caps.get(:persist_mount_shared_folder) }
-  let(:mount_options_cap){ double("opts") }
+  let(:folder_plugin){ double("folder_plugin") }
   let(:ssh_info) {{
     :username => "vagrant"
   }}
-  let (:fstab_folders) { {
-    "test1" => {:guestpath=>"/test1", :hostpath=>"/my/host/path", :disabled=>false, :__vagrantfile=>true, :owner=>"vagrant", :group=>"vagrant", :mount_options=>["uid=1234", "gid=1234"]},
-    "vagrant" => {:guestpath=>"/vagrant", :hostpath=>"/my/host/vagrant", :disabled=>false, :__vagrantfile=>true, :owner=>"vagrant", :group=>"vagrant", :mount_options=>["uid=1234", "gid=1234"]}
-  }}
+  let (:fstab_folders) {
+    Vagrant::Plugin::V2::SyncedFolder::Collection[
+      {
+        "test1" => {guestpath: "/test1", hostpath: "/my/host/path", disabled: false, plugin: folder_plugin,
+          __vagrantfile: true, owner: "vagrant", group: "vagrant", mount_options: ["uid=#{options_uid}", "gid=#{options_gid}"]},
+        "vagrant" => {guestpath: "/vagrant", hostpath: "/my/host/vagrant", disabled: false, __vagrantfile: true,
+          owner: "vagrant", group: "vagrant", mount_options: ["uid=#{options_uid}", "gid=#{options_gid}}"], plugin: folder_plugin}
+      }
+    ]
+  }
   let (:folders) { {
     :virtualbox => fstab_folders
   } }
@@ -27,9 +33,9 @@ describe "VagrantPlugins::GuestLinux::Cap::PersistMountSharedFolder" do
   before do
     allow(machine).to receive(:communicate).and_return(comm)
     allow(machine).to receive(:ssh_info).and_return(ssh_info)
-    allow(machine).to receive_message_chain(:synced_folders, :types).and_return( { :virtualbox => mount_options_cap } )
-    allow(mount_options_cap).to receive(:capability).with(:mount_options, any_args).and_return(["uid=#{options_uid},gid=#{options_gid}", options_uid, options_gid])
-    allow(mount_options_cap).to receive(:capability).with(:mount_type).and_return("vboxsf")
+    allow(folder_plugin).to receive(:capability).with(:mount_options, any_args).
+      and_return(["uid=#{options_uid},gid=#{options_gid}", options_uid, options_gid])
+    allow(folder_plugin).to receive(:capability).with(:mount_type).and_return("vboxsf")
   end
 
   after do
@@ -38,11 +44,6 @@ describe "VagrantPlugins::GuestLinux::Cap::PersistMountSharedFolder" do
 
   describe ".persist_mount_shared_folder" do
 
-    let (:fstab_folders) { [
-      ["test1", {:guestpath=>"/test1", :hostpath=>"/my/host/path", :disabled=>false, :__vagrantfile=>true, :owner=>"vagrant", :group=>"vagrant", :mount_options=>["uid=#{options_uid}", "gid=#{options_gid}"] }],
-      ["vagrant", {:guestpath=>"/vagrant", :hostpath=>"/my/host/vagrant", :disabled=>false, :__vagrantfile=>true, :owner=>"vagrant", :group=>"vagrant", :mount_options=>["uid=#{options_uid}", "gid=#{options_gid}"] }]
-    ]}
-
     let(:ui){ double(:ui) }
 
     before do
@@ -56,6 +57,7 @@ describe "VagrantPlugins::GuestLinux::Cap::PersistMountSharedFolder" do
       expected_entry_test = "test1 /test1 vboxsf uid=#{options_uid},gid=#{options_gid},nofail 0 0"
       expect(cap).to receive(:remove_vagrant_managed_fstab)
       expect(comm).to receive(:sudo).with(/#{expected_entry_test}\n#{expected_entry_vagrant}/)
+
       cap.persist_mount_shared_folder(machine, folders)
     end
 
diff --git a/test/unit/vagrant/action/builtin/mixin_synced_folders_test.rb b/test/unit/vagrant/action/builtin/mixin_synced_folders_test.rb
index adaf6af3a..5d3bc1a90 100644
--- a/test/unit/vagrant/action/builtin/mixin_synced_folders_test.rb
+++ b/test/unit/vagrant/action/builtin/mixin_synced_folders_test.rb
@@ -14,6 +14,7 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
   end
 
   let(:data_dir) { Pathname.new(Dir.mktmpdir("vagrant-test-mixin-synced-folders")) }
+  let(:folders_class) { Vagrant::Plugin::V2::SyncedFolder::Collection }
 
   let(:machine) do
     double("machine").tap do |machine|
@@ -91,7 +92,7 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
   end
 
   describe "synced_folders" do
-    let(:folders) { {} }
+    let(:folders) { folders_class.new }
     let(:plugins) { {} }
 
     before do
@@ -118,14 +119,14 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
       result = subject.synced_folders(machine)
       expect(result.length).to eq(2)
       expect(result[:default]).to eq({
-        "another" => folders["another"].merge(__vagrantfile: true),
-        "foo" => folders["foo"].merge(__vagrantfile: true),
-        "root" => folders["root"].merge(__vagrantfile: true),
+        "another" => folders["another"].merge(__vagrantfile: true, plugin: true),
+        "foo" => folders["foo"].merge(__vagrantfile: true, plugin: true),
+        "root" => folders["root"].merge(__vagrantfile: true, plugin: true),
       })
       expect(result[:nfs]).to eq({
-        "nfs" => folders["nfs"].merge(__vagrantfile: true),
+        "nfs" => folders["nfs"].merge(__vagrantfile: true, plugin: true),
       })
-      expect(result.types.keys).to eq([:default, :nfs]) 
+      expect(result.types).to eq([:default, :nfs])
     end
 
     it "should return the proper set of folders of a custom config" do
@@ -139,9 +140,9 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
       result = subject.synced_folders(machine, config: other)
       expect(result.length).to eq(1)
       expect(result[:default]).to eq({
-        "bar" => other_folders["bar"],
+        "bar" => other_folders["bar"].merge(plugin: true),
       })
-      expect(result.types.keys).to eq([:default]) 
+      expect(result.types).to eq([:default])
     end
 
     it "should error if an explicit type is unusable" do
@@ -159,7 +160,7 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
       result = subject.synced_folders(machine)
       expect(result.length).to eq(1)
       expect(result[:default].length).to eq(1)
-      expect(result.types.keys).to eq([:default]) 
+      expect(result.types).to eq([:default])
     end
 
     it "should scope hash override the settings" do
@@ -171,13 +172,13 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
 
       result = subject.synced_folders(machine)
       expect(result[:nfs]["root"][:foo]).to eql("bar")
-      expect(result.types.keys).to eq([:nfs]) 
+      expect(result.types).to eq([:nfs])
     end
 
     it "returns {} if cached read with no cache" do
       result = subject.synced_folders(machine, cached: true)
       expect(result).to eql({})
-      expect(result.types).to eq({}) 
+      expect(result.types).to eq([])
     end
 
     it "should be able to save and retrieve cached versions" do
@@ -196,12 +197,12 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
       result = subject.synced_folders(machine, cached: true)
       expect(result.length).to eq(2)
       expect(result[:default]).to eq({
-        "another" => old_folders["another"].merge(__vagrantfile: true),
-        "foo" => old_folders["foo"].merge(__vagrantfile: true),
-        "root" => old_folders["root"].merge(__vagrantfile: true),
+        "another" => old_folders["another"].merge(__vagrantfile: true, plugin: true),
+        "foo" => old_folders["foo"].merge(__vagrantfile: true, plugin: true),
+        "root" => old_folders["root"].merge(__vagrantfile: true, plugin: true),
       })
-      expect(result[:nfs]).to eq({ "nfs" => old_folders["nfs"].merge(__vagrantfile: true) })
-      expect(result.types.keys).to eq([:default, :nfs]) 
+      expect(result[:nfs]).to eq({ "nfs" => old_folders["nfs"].merge(__vagrantfile: true, plugin: true) })
+      expect(result.types).to eq([:default, :nfs])
     end
 
     it "should be able to save and retrieve cached versions" do
@@ -227,13 +228,13 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
       result = subject.synced_folders(machine, cached: true)
       expect(result.length).to eq(2)
       expect(result[:default]).to eq({
-        "foo" => { type: "default" },
-        "bar" => { type: "default", __vagrantfile: true},
+        "foo" => { type: "default", plugin: true },
+        "bar" => { type: "default", __vagrantfile: true, plugin: true },
       })
       expect(result[:nfs]).to eq({
-        "baz" => { type: "nfs", __vagrantfile: true }
+        "baz" => { type: "nfs", __vagrantfile: true, plugin: true }
       })
-      expect(result.types.keys).to eq([:default, :nfs]) 
+      expect(result.types).to eq([:default, :nfs])
     end
 
     it "should remove items from the vagrantfile that were removed" do
@@ -255,17 +256,17 @@ describe Vagrant::Action::Builtin::MixinSyncedFolders do
       result = subject.synced_folders(machine, cached: true)
       expect(result.length).to eq(2)
       expect(result[:default]).to eq({
-        "bar" => { type: "default", __vagrantfile: true},
+        "bar" => { type: "default", __vagrantfile: true, plugin: true},
       })
       expect(result[:nfs]).to eq({
-        "baz" => { type: "nfs", __vagrantfile: true }
+        "baz" => { type: "nfs", __vagrantfile: true, plugin: true }
       })
-      expect(result.types.keys).to eq([:default, :nfs]) 
+      expect(result.types).to eq([:default, :nfs])
     end
   end
 
   describe "#save_synced_folders" do
-    let(:folders) { {} }
+    let(:folders) { folders_class.new }
     let(:options) { {} }
     let(:output_file) { double("output_file") }