Fixed possible null exception in control flow node.

ICSharpCode.NRefactory.CSharp/Analysis/ControlFlow.cs

@@ -1,4 +1,4 @@
-// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
+// Copyright (c) AlphaSierraPapa for the SharpDevelop Team
 // 
 // Permission is hereby granted, free of charge, to any person obtaining a copy of this
 // software and associated documentation files (the "Software"), to deal in the Software
@@ -420,6 +420,7 @@ namespace ICSharpCode.NRefactory.CSharp.Analysis
 					falseEnd = ifElseStatement.FalseStatement.AcceptVisitor(this, falseBegin);
 				}
 				ControlFlowNode end = builder.CreateEndNode(ifElseStatement);
+				if (trueEnd != null)
 					Connect(trueEnd, end);
 				if (falseEnd != null) {
 					Connect(falseEnd, end);