CAST function parameter fragment is incorrectly calculated during parsing

[SShetgaonkar]

Version - 180.78.1

Parser - TSql180Parser and TSql170Parser

Issue Description : When the fragment for the parameter in CAST function is calculated it consist only the "'Test'" part and does not contain the "AS VARCHAR(20)" section.

Steps to reproduce -

Try parsing the below SQL script with the parser:

SELECT CAST('TEST' AS VARCHAR(20))

Example -

using Microsoft.SqlServer.TransactSql.ScriptDom;

internal class Program
{
    static void Main(string[] args)
    {
        var script = "Example Script";
        var parser = new TSql180Parser(true);
        var fragment = parser.Parse(new StringReader(script), out var parseErrors);

        if (parseErrors.Count > 0)
        {
            foreach(var parseError in parseErrors)
                Console.WriteLine(parseError.Message);
        }
        else
        {
            Console.WriteLine("Parsed successfully");
        }
    }
}

Actual Output - Parameter fragment given by the parser - 'TEST'
Expected Output - Parameter fragment - 'TEST' AS VARCHAR(20)