Reproduction code

main.cs

using System;
using System.Collections;
using System.Collections.Generic;
using System.Diagnostics;
using System.Runtime.CompilerServices;
using System.Threading;

namespace CompilerGeneratedEnhancement
{
	// Token: 0x02000002 RID: 2
	public partial class Class1
	{
		// Token: 0x06000005 RID: 5 RVA: 0x000020D4 File Offset: 0x000002D4
		public void EditThisMethod()
		{
			Console.WriteLine("How to reproduce:");
			Console.WriteLine("1. Click on 'Edit C#'");
			Console.WriteLine("2. Click on 'Compile'");
			Console.WriteLine("Things that are wrong:");
			Console.WriteLine("1. Compiler generated lambda helper classes/methods should be removed");
			Console.WriteLine("2. Compiler generated backing fields for properties should be removed");
			Console.WriteLine("3. Compiler generated backing fields for events should be removed");
			Console.WriteLine("4. ");
			this.MyEvent += new EventHandler(this.Class1_MyEvent);
			this.MyProperty = this;
		}
	}
}

main.g.cs

//This file contains the code in *.g.cs used to define the remaining class stuff
namespace CompilerGeneratedEnhancement
{
	// Token: 0x02000002 RID: 2
	public partial class Class1
	{
		// Token: 0x17000001 RID: 1
		public global::CompilerGeneratedEnhancement.Class1 MyProperty
		{
			// Token: 0x06000001 RID: 1 RVA: 0x00002050 File Offset: 0x00000250
			[global::System.Runtime.CompilerServices.CompilerGenerated]
			get
			{
				return default(global::CompilerGeneratedEnhancement.Class1);
			}
			// Token: 0x06000002 RID: 2 RVA: 0x00002058 File Offset: 0x00000258
			[global::System.Runtime.CompilerServices.CompilerGenerated]
			set
			{
			}
		}

		// Token: 0x14000001 RID: 1
		public event global::System.EventHandler MyEvent
		{
			// Token: 0x06000003 RID: 3 RVA: 0x00002064 File Offset: 0x00000264
			[global::System.Runtime.CompilerServices.CompilerGenerated]
			add
			{
			}
			// Token: 0x06000004 RID: 4 RVA: 0x0000209C File Offset: 0x0000029C
			[global::System.Runtime.CompilerServices.CompilerGenerated]
			remove
			{
			}
		}

		public // Token: 0x06000006 RID: 6 RVA: 0x00002155 File Offset: 0x00000355
		void Class1_MyEvent(object sender, global::System.EventArgs e)
		{
		}

		// Token: 0x06000007 RID: 7 RVA: 0x0000215D File Offset: 0x0000035D
		public void MethodWithLambda()
		{
		}

		// Token: 0x06000008 RID: 8 RVA: 0x0000218B File Offset: 0x0000038B
		public global::System.Collections.Generic.IEnumerable<string> YieldReturnTest()
		{
			return default(global::System.Collections.Generic.IEnumerable<string>);
		}

		// Token: 0x06000009 RID: 9 RVA: 0x0000219B File Offset: 0x0000039B
		public Class1()
		{
		}

		public // Token: 0x04000001 RID: 1
		global::System.Collections.Generic.List<string> _yieldReturnTestStorage;

		// Token: 0x04000002 RID: 2
		[global::System.Runtime.CompilerServices.CompilerGenerated]
		public global::CompilerGeneratedEnhancement.Class1 <MyProperty>k__BackingField;

		// Token: 0x04000003 RID: 3
		[global::System.Runtime.CompilerServices.CompilerGenerated]
		public global::System.EventHandler MyEvent;

		// Token: 0x02000004 RID: 4
		[global::System.Runtime.CompilerServices.CompilerGenerated]
		public sealed class <YieldReturnTest>d__11 : global::System.Collections.Generic.IEnumerable<string>, global::System.Collections.IEnumerable, global::System.Collections.Generic.IEnumerator<string>, global::System.IDisposable, global::System.Collections.IEnumerator
		{
			// Token: 0x0600000D RID: 13 RVA: 0x000021F1 File Offset: 0x000003F1
			[global::System.Diagnostics.DebuggerHidden]
			public <YieldReturnTest>d__11(int <>1__state)
			{
			}

			// Token: 0x0600000E RID: 14 RVA: 0x0000220C File Offset: 0x0000040C
			[global::System.Diagnostics.DebuggerHidden]
			void global::System.IDisposable.Dispose()
			{
			}

			// Token: 0x0600000F RID: 15 RVA: 0x0000224C File Offset: 0x0000044C
			bool global::System.Collections.IEnumerator.MoveNext()
			{
				return default(bool);
			}

			public // Token: 0x06000010 RID: 16 RVA: 0x00002318 File Offset: 0x00000518
			void <>m__Finally1()
			{
			}

			// Token: 0x17000002 RID: 2
			string global::System.Collections.Generic.IEnumerator<string>.Current
			{
				// Token: 0x06000011 RID: 17 RVA: 0x00002333 File Offset: 0x00000533
				[global::System.Diagnostics.DebuggerHidden]
				get
				{
					return default(string);
				}
			}

			// Token: 0x06000012 RID: 18 RVA: 0x0000233B File Offset: 0x0000053B
			[global::System.Diagnostics.DebuggerHidden]
			void global::System.Collections.IEnumerator.Reset()
			{
			}

			// Token: 0x17000003 RID: 3
			object global::System.Collections.IEnumerator.Current
			{
				// Token: 0x06000013 RID: 19 RVA: 0x00002333 File Offset: 0x00000533
				[global::System.Diagnostics.DebuggerHidden]
				get
				{
					return default(object);
				}
			}

			// Token: 0x06000014 RID: 20 RVA: 0x00002344 File Offset: 0x00000544
			[global::System.Diagnostics.DebuggerHidden]
			global::System.Collections.Generic.IEnumerator<string> global::System.Collections.Generic.IEnumerable<string>.GetEnumerator()
			{
				return default(global::System.Collections.Generic.IEnumerator<string>);
			}

			// Token: 0x06000015 RID: 21 RVA: 0x00002387 File Offset: 0x00000587
			[global::System.Diagnostics.DebuggerHidden]
			global::System.Collections.IEnumerator global::System.Collections.IEnumerable.GetEnumerator()
			{
				return default(global::System.Collections.IEnumerator);
			}

			public // Token: 0x04000006 RID: 6
			int <>1__state;

			public // Token: 0x04000007 RID: 7
			string <>2__current;

			public // Token: 0x04000008 RID: 8
			int <>l__initialThreadId;

			// Token: 0x04000009 RID: 9
			public global::CompilerGeneratedEnhancement.Class1 <>4__this;

			public // Token: 0x0400000A RID: 10
			global::System.Collections.Generic.List<string>.Enumerator <>s__1;

			public // Token: 0x0400000B RID: 11
			string <s>5__2;
		}
	}
}

original.cs

using System;
using System.Collections.Generic;

namespace CompilerGeneratedEnhancement
{
    public class Class1
    {
        private List<string> _yieldReturnTestStorage = new List<string> { "1", "2", "3" };

        public Class1 MyProperty { get; set; }

        public event EventHandler MyEvent;

        public void EditThisMethod()
        {
            Console.WriteLine("How to reproduce:");
            Console.WriteLine("1. Click on 'Edit C#'");
            Console.WriteLine("2. Click on 'Compile'");
            Console.WriteLine("Things that are wrong:");
            Console.WriteLine("1. Compiler generated lambda helper classes/methods should be removed");
            Console.WriteLine("2. Compiler generated backing fields for properties should be removed");
            Console.WriteLine("3. Compiler generated backing fields for events should be removed");
            MyEvent += Class1_MyEvent;
            MyProperty = this;
        }

        private void Class1_MyEvent(object sender, EventArgs e)
        {
            throw new NotImplementedException();
        }

        public void MethodWithLambda()
        {
            _yieldReturnTestStorage.ForEach(s => Console.WriteLine(s));
        }

        public IEnumerable<string> YieldReturnTest()
        {
            foreach (string s in _yieldReturnTestStorage)
            {
                yield return s;
            }
        }
    }
}