public static string PickSafeName(AstNode node, IEnumerable <string> candidates)
        {
            var existingNames = new VariableNameCollector().Collect(node);

            return(candidates.FirstOrDefault(name => !existingNames.Contains(name)));
        }
		public static string PickSafeName (AstNode node, IEnumerable<string> candidates)
		{
			var existingNames = new VariableNameCollector ().Collect (node);
			return candidates.FirstOrDefault (name => !existingNames.Contains (name));
		}