Units of Measure Validator for C#

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using ICSharpCode.NRefactory.CSharp;
using System.IO;
using System.Text.RegularExpressions;
using ICSharpCode.NRefactory.TypeSystem;
using ICSharpCode.NRefactory.CSharp.TypeSystem;
using ICSharpCode.NRefactory.CSharp.Resolver;
using ICSharpCode.NRefactory.Semantics;

namespace HDLibrary.UnitsOfMeasure.Validator
{
    class SharedElementScope
    {
        private Dictionary<object, SharedElement> sharedElements = new Dictionary<object, SharedElement>();

        public ISharedElement GetSharedElement(ResolveResult resolveResult, out bool isNew)
        {
            object key = null;
            MemberResolveResult mrr = resolveResult as MemberResolveResult;
            if (mrr != null)
                key = mrr.Member;
            else
            {
                LocalResolveResult lrr = resolveResult as LocalResolveResult;
                if (lrr != null)
                    key = lrr.Variable;
            }

            isNew = false;

            if (key == null)
                return null;

            SharedElement result;

            if (!sharedElements.TryGetValue(key, out result))
            {
                result = new SharedElement();
                sharedElements.Add(key, result);
                isNew = true;
            }

            return result;
        }

        private class SharedElement : ISharedElement
        {
            public IUnitDescription UnitDescription { get; set; }
            //public Unit Unit { get; set; }
            //public Unit[] Parameters { get; set; }
        }
    }
}