Added obsolete EmptyExpression. (Removing was a breaking change)

ICSharpCode.NRefactory.CSharp/Ast/Expressions/ErrorExpression.cs

@@ -27,6 +27,42 @@ using System;
 
 namespace ICSharpCode.NRefactory.CSharp
 {
+	[Obsolete("This class is obsolete. Remove all referencing code.")]
+	public class EmptyExpression : AstNode
+	{
+		#region implemented abstract members of AstNode
+
+		public override void AcceptVisitor(IAstVisitor visitor)
+		{
+			throw new NotImplementedException();
+		}
+
+		public override T AcceptVisitor<T>(IAstVisitor<T> visitor)
+		{
+			throw new NotImplementedException();
+		}
+
+		public override S AcceptVisitor<T, S>(IAstVisitor<T, S> visitor, T data)
+		{
+			throw new NotImplementedException();
+		}
+
+		protected internal override bool DoMatch(AstNode other, ICSharpCode.NRefactory.PatternMatching.Match match)
+		{
+			throw new NotImplementedException();
+		}
+
+		public override NodeType NodeType {
+			get {
+				throw new NotImplementedException();
+			}
+		}
+
+		#endregion
+
+
+	}
+
 	public class ErrorExpression : Expression
 	{
 		TextLocation location;