diff --git a/lib/vagrant/environment.rb b/lib/vagrant/environment.rb
index 46899197c..62d059dd1 100644
--- a/lib/vagrant/environment.rb
+++ b/lib/vagrant/environment.rb
@@ -755,9 +755,9 @@ module Vagrant
           next
         end
 
-        @logger.info("Loading plugin from JSON: #{plugin}")
+        @logger.info("Loading plugin from JSON: #{name}")
         begin
-          Vagrant.require_plugin(plugin)
+          Vagrant.require_plugin(name)
         rescue Errors::PluginLoadError => e
           @ui.error(e.message + "\n")
         rescue Errors::PluginLoadFailed => e
diff --git a/plugins/commands/plugin/action/license_plugin.rb b/plugins/commands/plugin/action/license_plugin.rb
index b69e52749..518c1824c 100644
--- a/plugins/commands/plugin/action/license_plugin.rb
+++ b/plugins/commands/plugin/action/license_plugin.rb
@@ -18,7 +18,7 @@ module VagrantPlugins
 
         def call(env)
           # Get the list of installed plugins according to the state file
-          installed = Set.new(env[:plugin_state_file].installed_plugins)
+          installed = env[:plugin_state_file].installed_plugins.keys
 
           # If the plugin we're trying to license doesn't exist in the
           # state file, then it is an error.
diff --git a/plugins/commands/plugin/action/list_plugins.rb b/plugins/commands/plugin/action/list_plugins.rb
index b3a3392b1..f5dd0574b 100644
--- a/plugins/commands/plugin/action/list_plugins.rb
+++ b/plugins/commands/plugin/action/list_plugins.rb
@@ -18,7 +18,7 @@ module VagrantPlugins
 
         def call(env)
           # Get the list of installed plugins according to the state file
-          installed = Set.new(env[:plugin_state_file].installed_plugins)
+          installed = env[:plugin_state_file].installed_plugins.keys
 
           # Go through the plugins installed in this environment and
           # get the latest version of each.
diff --git a/plugins/commands/plugin/action/plugin_exists_check.rb b/plugins/commands/plugin/action/plugin_exists_check.rb
index c56bd9c14..abe8d43cf 100644
--- a/plugins/commands/plugin/action/plugin_exists_check.rb
+++ b/plugins/commands/plugin/action/plugin_exists_check.rb
@@ -12,7 +12,7 @@ module VagrantPlugins
 
         def call(env)
           # Get the list of installed plugins according to the state file
-          installed = Set.new(env[:plugin_state_file].installed_plugins)
+          installed = env[:plugin_state_file].installed_plugins.keys
           if !installed.include?(env[:plugin_name])
             raise Vagrant::Errors::PluginNotInstalled,
               name: env[:plugin_name]
diff --git a/plugins/commands/plugin/action/prune_gems.rb b/plugins/commands/plugin/action/prune_gems.rb
index ae5a38196..d5e754994 100644
--- a/plugins/commands/plugin/action/prune_gems.rb
+++ b/plugins/commands/plugin/action/prune_gems.rb
@@ -34,7 +34,7 @@ module VagrantPlugins
           @logger.info("Pruning gems...")
 
           # Get the list of installed plugins according to the state file
-          installed = Set.new(env[:plugin_state_file].installed_plugins)
+          installed = env[:plugin_state_file].installed_plugins.keys
 
           # Get the actual specifications of installed gems
           all_specs = env[:gem_helper].with_environment do
diff --git a/plugins/commands/plugin/state_file.rb b/plugins/commands/plugin/state_file.rb
index 6860bdd09..7846bf7b0 100644
--- a/plugins/commands/plugin/state_file.rb
+++ b/plugins/commands/plugin/state_file.rb
@@ -32,11 +32,11 @@ module VagrantPlugins
         save!
       end
 
-      # This returns a list of installed plugins according to the state
+      # This returns a hash of installed plugins according to the state
       # file. Note that this may _not_ directly match over to actually
       # installed gems.
       #
-      # @return [Array<String>]
+      # @return [Hash]
       def installed_plugins
         @data["installed"]
       end