Commented Unassigned: NullReferenceException after pasting into the JS editor [1363]

Pasting into the JS editor can cause the following exception

```
Log Name: Application
Source: .NET Runtime
Date: 22/08/2014 14:27:07
Event ID: 1026
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: ******************
Description:
Application: devenv.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.NullReferenceException
Stack:
at Microsoft.NodejsTools.Analysis.UnionComparer.GetHashCode(Microsoft.NodejsTools.Analysis.AnalysisProxy)
at System.Collections.Generic.Dictionary`2[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].Insert(System.__Canon, System.__Canon, Boolean)
at Microsoft.NodejsTools.Analysis.Analyzer.KeyValueDependencyInfo.MakeUnionStronger()
at Microsoft.NodejsTools.Analysis.Analyzer.DependentKeyValue.AddTypes(Microsoft.NodejsTools.Analysis.ProjectEntry, Microsoft.NodejsTools.Analysis.JsAnalyzer, Microsoft.NodejsTools.Analysis.IAnalysisSet, Microsoft.NodejsTools.Analysis.IAnalysisSet, Boolean)
at Microsoft.NodejsTools.Analysis.Values.ExpandoValue.SetIndex(Microsoft.NodejsTools.Parsing.Node, Microsoft.NodejsTools.Analysis.AnalysisUnit, Microsoft.NodejsTools.Analysis.IAnalysisSet, Microsoft.NodejsTools.Analysis.IAnalysisSet)
at Microsoft.NodejsTools.Analysis.AnalysisSetExtensions.SetIndex(Microsoft.NodejsTools.Analysis.IAnalysisSet, Microsoft.NodejsTools.Parsing.Node, Microsoft.NodejsTools.Analysis.AnalysisUnit, Microsoft.NodejsTools.Analysis.IAnalysisSet, Microsoft.NodejsTools.Analysis.IAnalysisSet)
at Microsoft.NodejsTools.Analysis.Analyzer.ExpressionEvaluator.AssignTo(Microsoft.NodejsTools.Parsing.Node, Microsoft.NodejsTools.Parsing.Expression, Microsoft.NodejsTools.Analysis.IAnalysisSet)
at Microsoft.NodejsTools.Analysis.Analyzer.ExpressionEvaluator.EvaluateBinary(Microsoft.NodejsTools.Analysis.Analyzer.ExpressionEvaluator, Microsoft.NodejsTools.Parsing.Node)
at Microsoft.NodejsTools.Analysis.Analyzer.ExpressionEvaluator.EvaluateWorker(Microsoft.NodejsTools.Parsing.Node)
at Microsoft.NodejsTools.Analysis.Analyzer.DDG.Walk(Microsoft.NodejsTools.Parsing.ExpressionStatement)
at Microsoft.NodejsTools.Parsing.ExpressionStatement.Walk(Microsoft.NodejsTools.Parsing.AstVisitor)
at Microsoft.NodejsTools.Analysis.Analyzer.DDG.Walk(Microsoft.NodejsTools.Parsing.Block)
at Microsoft.NodejsTools.Parsing.Block.Walk(Microsoft.NodejsTools.Parsing.AstVisitor)
at Microsoft.NodejsTools.Analysis.Analyzer.DDG.Walk(Microsoft.NodejsTools.Parsing.IfNode)
at Microsoft.NodejsTools.Parsing.IfNode.Walk(Microsoft.NodejsTools.Parsing.AstVisitor)
at Microsoft.NodejsTools.Analysis.Analyzer.DDG.Walk(Microsoft.NodejsTools.Parsing.Block)
at Microsoft.NodejsTools.Parsing.Block.Walk(Microsoft.NodejsTools.Parsing.AstVisitor)
at Microsoft.NodejsTools.Analysis.Analyzer.DDG.Walk(Microsoft.NodejsTools.Parsing.IfNode)
at Microsoft.NodejsTools.Parsing.IfNode.Walk(Microsoft.NodejsTools.Parsing.AstVisitor)
at Microsoft.NodejsTools.Analysis.Analyzer.DDG.Walk(Microsoft.NodejsTools.Parsing.Block)
at Microsoft.NodejsTools.Parsing.Block.Walk(Microsoft.NodejsTools.Parsing.AstVisitor)
at Microsoft.NodejsTools.Analysis.Analyzer.FunctionAnalysisUnit.AnalyzeWorker(Microsoft.NodejsTools.Analysis.Analyzer.DDG, System.Threading.CancellationToken)
at Microsoft.NodejsTools.Analysis.Analyzer.DDG.Analyze(Microsoft.NodejsTools.Analysis.Deque`1<Microsoft.NodejsTools.Analysis.AnalysisUnit>, System.Threading.CancellationToken)
at Microsoft.NodejsTools.Analysis.JsAnalyzer.AnalyzeQueuedEntries(System.Threading.CancellationToken)
at Microsoft.NodejsTools.Intellisense.AnalysisQueue+GroupAnalysis.Analyze(System.Threading.CancellationToken)
at Microsoft.NodejsTools.Intellisense.AnalysisQueue.Worker(System.Object)
at System.Threading.ThreadHelper.ThreadStart_Context(System.Object)
at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
at System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
at System.Threading.ThreadHelper.ThreadStart(System.Object)
```

It doesn't happen immediately, usually after pasting 3-4 times (not sure if it matters whether it's concurrent pasting or not).
Comments: Probably related to https://nodejstools.codeplex.com/workitem/1350