Remove `Bag<K, V>`

src/BizHawk.Common/CustomCollections.cs

@@ -1,42 +1,12 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
-using System.Linq;
 using System.Runtime.Serialization;
 
 using BizHawk.Common.CollectionExtensions;
 
 namespace BizHawk.Common
 {
-	/// <summary>Wrapper over <see cref="WorkingDictionary{TKey, TValue}">WorkingDictionary</see>&lt;<typeparamref name="TKey"/>, <see cref="List{T}">List</see>&lt;<typeparamref name="TValue"/>>>.</summary>
-	[Serializable]
-	public class Bag<TKey, TValue> : IEnumerable<TValue> where TKey : notnull
-	{
-		private readonly WorkingDictionary<TKey, List<TValue>> dictionary = new WorkingDictionary<TKey, List<TValue>>();
-
-		public IList<TKey> Keys => dictionary.Keys.ToList();
-
-		public List<TValue> this[TKey key]
-		{
-#pragma warning disable CS8603 // the only call to the index setter of `dictionary` is this index setter, which only takes non-null `List<TValue>`s
-			get => dictionary[key];
-#pragma warning restore CS8603
-			set => dictionary[key] = value;
-		}
-
-		public void Add(TKey key, IEnumerable<TValue> val) => this[key].AddRange(val);
-
-		public void Add(TKey key, TValue val) => this[key].Add(val);
-
-		public bool ContainsKey(TKey key) => dictionary.ContainsKey(key);
-
-		IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
-
-		public IEnumerator<TValue> GetEnumerator() => dictionary.Values.SelectMany(lv => lv).GetEnumerator();
-
-		public IEnumerator<KeyValuePair<TKey, List<TValue>>> GetKVPEnumerator() => dictionary.GetEnumerator();
-	}
-
 	public class SortedList<T> : ICollection<T>
 		where T : IComparable<T>
 	{

src/BizHawk.Emulation.Cores/Consoles/Nintendo/NES/BootGodDB.cs

@@ -4,6 +4,7 @@ using System.IO;
 using System.Xml;
 using System.Threading;
 using BizHawk.Common;
+using BizHawk.Common.CollectionExtensions;
 using BizHawk.Common.StringExtensions;
 
 namespace BizHawk.Emulation.Cores.Nintendo.NES
@@ -17,7 +18,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 
 		private readonly bool validate = true;
 
-		private readonly Bag<string, CartInfo> _sha1Table = new Bag<string, CartInfo>();
+		private readonly Dictionary<string, List<CartInfo>> _sha1Table = new();
 
 		private static BootGodDb instance;
 
@@ -124,7 +125,7 @@ namespace BizHawk.Emulation.Cores.Nintendo.NES
 					case 4:
 						if (xmlReader.NodeType == XmlNodeType.EndElement && xmlReader.Name == "cartridge")
 						{
-							_sha1Table[currCart.Sha1].Add(currCart);
+							_sha1Table.GetValueOrPutNew(currCart.Sha1).Add(currCart);
 							currCart = null;
 							state = 5;
 						}