Extract item restrictions to separate class

Move similar classes to folder

PKHeX.Core/Legality/Core.cs

@@ -448,39 +448,6 @@ internal static int GetMaxLanguageID(int generation)
             };
         }
 
-        private static bool[] GetReleasedHeldItems(int generation)
-        {
-            return generation switch
-            {
-                2 => ReleasedHeldItems_2,
-                3 => ReleasedHeldItems_3,
-                4 => ReleasedHeldItems_4,
-                5 => ReleasedHeldItems_5,
-                6 => ReleasedHeldItems_6,
-                7 => ReleasedHeldItems_7,
-                8 => ReleasedHeldItems_8,
-                _ => Array.Empty<bool>()
-            };
-        }
-
-        internal static bool IsHeldItemAllowed(PKM pkm)
-        {
-            if (pkm is PB7)
-                return pkm.HeldItem == 0;
-            return IsHeldItemAllowed(pkm.HeldItem, pkm.Format);
-        }
-
-        private static bool IsHeldItemAllowed(int item, int generation)
-        {
-            if (item == 0)
-                return true;
-            if (item < 0)
-                return false;
-
-            var items = GetReleasedHeldItems(generation);
-            return items.Length > item && items[item];
-        }
-
         private static bool IsEvolvedFormChange(PKM pkm)
         {
             if (pkm.IsEgg)

PKHeX.Core/Legality/Restrictions/ItemRestrictions.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+
+using static PKHeX.Core.Legal;
+
+namespace PKHeX.Core
+{
+    /// <summary>
+    /// Information about Held Item Restrictions
+    /// </summary>
+    public static class ItemRestrictions
+    {
+        /// <summary>
+        /// Checks if a <see cref="PKM.HeldItem"/> is available to be held in the current <see cref="PKM.Format"/>.
+        /// </summary>
+        /// <param name="pk">Entity data</param>
+        /// <returns>True if able to be held, false if not</returns>
+        public static bool IsHeldItemAllowed(PKM pk)
+        {
+            if (pk is PB7)
+                return pk.HeldItem == 0;
+            return IsHeldItemAllowed(pk.HeldItem, pk.Format);
+        }
+
+        /// <summary>
+        /// Checks if an <see cref="item"/> is available to be held in <see cref="generation"/>.
+        /// </summary>
+        /// <param name="item">Held Item ID</param>
+        /// <param name="generation">Generation Number</param>
+        /// <returns>True if able to be held, false if not</returns>
+        public static bool IsHeldItemAllowed(int item, int generation)
+        {
+            if (item == 0)
+                return true;
+            if (item < 0)
+                return false;
+
+            var items = GetReleasedHeldItems(generation);
+            return items.Count > item && items[item];
+        }
+
+        private static IReadOnlyList<bool> GetReleasedHeldItems(int generation)
+        {
+            return generation switch
+            {
+                2 => ReleasedHeldItems_2,
+                3 => ReleasedHeldItems_3,
+                4 => ReleasedHeldItems_4,
+                5 => ReleasedHeldItems_5,
+                6 => ReleasedHeldItems_6,
+                7 => ReleasedHeldItems_7,
+                8 => ReleasedHeldItems_8,
+                _ => Array.Empty<bool>()
+            };
+        }
+    }
+}

PKHeX.Core/Legality/Verifiers/ItemVerifier.cs

@@ -12,7 +12,7 @@ public sealed class ItemVerifier : Verifier
         public override void Verify(LegalityAnalysis data)
         {
             var pkm = data.pkm;
-            if (!Legal.IsHeldItemAllowed(pkm))
+            if (!ItemRestrictions.IsHeldItemAllowed(pkm))
                 data.AddLine(GetInvalid(LItemUnreleased));
 
             if (pkm.Format == 3 && pkm.HeldItem == 175) // Enigma Berry