Created Issue: crash while defining a new function [974]

vs 2013, build 20509.00

I think I was just done typing something like
```
function trimVersion(
```

and it crashed:

```
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.Analyzer.ExpressionEvaluator.EvaluateWorker(Microsoft.NodejsTools.Parsing.Node)
at Microsoft.NodejsTools.Analysis.Analyzer.ExpressionEvaluator.EvaluateGroupingOperator(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.Parsing.JsAst.Walk(Microsoft.NodejsTools.Parsing.AstVisitor)
at Microsoft.NodejsTools.Analysis.AnalysisUnit.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, System.Action`1<Int32>, Int32)
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)
```