Fix initialization bugs

Author: rjmholt

Engine/Helper.cs

@@ -114,8 +114,8 @@ internal set
         /// </summary>
         private Helper()
         {
-            _ruleArguments = new Dictionary<string, Dictionary<string, object>>(StringComparer.OrdinalIgnoreCase);
             _commandInfoCache = new Lazy<CommandInfoCache>(() => new CommandInfoCache());
+            _ruleArguments = new Dictionary<string, Dictionary<string, object>>(StringComparer.OrdinalIgnoreCase);
             _cmdletToAliasDictionary = new Dictionary<string, List<string>>(StringComparer.OrdinalIgnoreCase);
             _aliasToCmdletDictionary = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
             _keywordBlockDictionary = new Dictionary<string, List<Tuple<int, int>>>(StringComparer.OrdinalIgnoreCase);
@@ -129,7 +129,7 @@ private Helper()
         /// A CommandInvocationIntrinsics instance for use in gathering
         /// information about available commands and aliases.
         /// </param>
-        public Helper(CommandInvocationIntrinsics invokeCommand) : base()
+        public Helper(CommandInvocationIntrinsics invokeCommand) : this()
         {
             _invokeCommand = invokeCommand;
         }
@@ -140,6 +140,10 @@ public Helper(CommandInvocationIntrinsics invokeCommand) : base()
         /// </summary>
         public void Initialize()
         {
+            _aliasToCmdletDictionary.Clear();
+            _cmdletToAliasDictionary.Clear();
+            _keywordBlockDictionary.Clear();
+            VariableAnalysisDictionary.Clear();
             if (_invokeCommand != null)
             {
                 IEnumerable<CommandInfo> aliases = _invokeCommand.GetCommands("*", CommandTypes.Alias, nameIsPattern: true);