Minor tweaks

== null
to
is null

PKHeX.Core/Editing/Bulk/BatchEditing.cs

@@ -432,7 +432,7 @@ private static ModifyResult SetPKMProperty(StringInstruction cmd, BatchInfo info
     private static bool IsFilterMatch(StringInstruction cmd, BatchInfo info, Dictionary<string, PropertyInfo>.AlternateLookup<ReadOnlySpan<char>> props)
     {
         var match = BatchFilters.FilterMods.Find(z => z.IsMatch(cmd.PropertyName));
-        if (match != null)
+        if (match is not null)
             return match.IsFiltered(info, cmd);
         return IsPropertyFiltered(cmd, info.Entity, props);
     }
@@ -447,7 +447,7 @@ private static bool IsFilterMatch(StringInstruction cmd, BatchInfo info, Diction
     private static bool IsFilterMatch(StringInstruction cmd, PKM pk, Dictionary<string, PropertyInfo>.AlternateLookup<ReadOnlySpan<char>> props)
     {
         var match = BatchFilters.FilterMods.Find(z => z.IsMatch(cmd.PropertyName));
-        if (match != null)
+        if (match is not null)
             return match.IsFiltered(pk, cmd);
         return IsPropertyFiltered(cmd, pk, props);
     }

PKHeX.Core/Editing/Bulk/BatchMods.cs

@@ -81,7 +81,7 @@ public static class BatchMods
     ];
 
     private static char GetOptionSuffix(ReadOnlySpan<char> str, ReadOnlySpan<char> prefix)
-        => str.Length == prefix.Length ? default : str[^1];
+        => str.Length == prefix.Length ? CommonEdits.OptionNone : str[^1];
 
     private static void SetRandomTeraType(PKM pk)
     {

PKHeX.Core/Editing/Bulk/IPropertyProvider.cs

@@ -20,7 +20,7 @@ public bool TryGetProperty(PKM pk, string prop, [NotNullWhen(true)] out string?
         {
             var value = pi.GetValue(pk);
             result = value?.ToString();
-            return result != null;
+            return result is not null;
         }
         catch
         {

PKHeX.Core/Editing/Bulk/Suggestion/BatchModifications.cs

@@ -89,7 +89,7 @@ public static ModifyResult SetSuggestedMetData(BatchInfo info)
     {
         var pk = info.Entity;
         var encounter = EncounterSuggestion.GetSuggestedMetInfo(pk);
-        if (encounter == null)
+        if (encounter is null)
             return ModifyResult.Error;
 
         var location = encounter.Location;

PKHeX.Core/Editing/CommonEdits.cs

@@ -444,10 +444,12 @@ public static string GetLocationString(this PKM pk, bool eggmet)
         return GameInfo.GetLocationName(eggmet, location, pk.Format, pk.Generation, pk.Version);
     }
 
+    public const char OptionNone = '\0';
+
     /// <summary>
     /// Gets a <see cref="PKM.EncryptionConstant"/> to match the requested option.
     /// </summary>
-    public static uint GetComplicatedEC(ISpeciesForm pk, char option = default)
+    public static uint GetComplicatedEC(ISpeciesForm pk, char option = OptionNone)
     {
         var species = pk.Species;
         var form = pk.Form;
@@ -455,7 +457,7 @@ public static uint GetComplicatedEC(ISpeciesForm pk, char option = default)
     }
 
     /// <inheritdoc cref="GetComplicatedEC(ISpeciesForm,char)"/>
-    public static uint GetComplicatedEC(ushort species, byte form, char option = default)
+    public static uint GetComplicatedEC(ushort species, byte form, char option = OptionNone)
     {
         var rng = Util.Rand;
         uint rand = rng.Rand32();

PKHeX.Core/Editing/Database/TrainerDatabase.cs

@@ -46,7 +46,7 @@ public sealed class TrainerDatabase
         if (possible.Count == 0)
             return null;
 
-        if (lang != null)
+        if (lang is not null)
         {
             possible = possible.Select(z =>
             {
@@ -70,7 +70,7 @@ public sealed class TrainerDatabase
         if (possible.Count == 0)
             return null;
 
-        if (lang != null)
+        if (lang is not null)
         {
             possible = possible.Select(z =>
             {

PKHeX.Core/Editing/PKM/QR/QRMessageUtil.cs

@@ -1,5 +1,6 @@
 using System;
 using System.Buffers;
+using System.Diagnostics;
 
 namespace PKHeX.Core;
 
@@ -23,7 +24,7 @@ public static class QRMessageUtil
     public static PKM? GetPKM(ReadOnlySpan<char> message, EntityContext context)
     {
         var data = DecodeMessagePKM(message);
-        if (data == null)
+        if (data is null)
             return null;
         return EntityFormat.GetFromBytes(data, context);
     }
@@ -93,7 +94,7 @@ public static string GetMessageBase64(ReadOnlySpan<byte> data, string server)
         if (message.StartsWith("http", StringComparison.Ordinal)) // inject url
             return DecodeMessageDataBase64(message);
 
-        const int g7size = 0xE8;
+        const int g7size = PokeCrypto.SIZE_6STORED; // 0xE8;
         const int g7intro = 0x30;
         if (message.StartsWith("POKE", StringComparison.Ordinal) && message.Length > g7intro + g7size) // G7 data
             return GetBytesFromMessage(message[g7intro..], g7size);
@@ -118,9 +119,15 @@ public static string GetMessageBase64(ReadOnlySpan<byte> data, string server)
 
     private static byte[] GetBytesFromMessage(ReadOnlySpan<char> input, int count)
     {
-        byte[] data = new byte[count];
-        for (int i = data.Length - 1; i >= 0; i--)
-            data[i] = (byte)input[i];
-        return data;
+        byte[] result = new byte[count];
+        GetBytesFromMessage(input, result);
+        return result;
+    }
+
+    private static void GetBytesFromMessage(ReadOnlySpan<char> input, Span<byte> output)
+    {
+        Debug.Assert(input.Length >= output.Length);
+        for (int i = 0; i < output.Length; i++)
+            output[i] = (byte)input[i];
     }
 }

PKHeX.Core/Editing/Saves/Editors/EventWork/Diff/EventWorkDiff.cs

@@ -30,7 +30,7 @@ public EventBlockDiff(string f1, string f2)
             return;
         var s1 = SaveUtil.GetVariantSAV(f1);
         var s2 = SaveUtil.GetVariantSAV(f2);
-        if (s1 == null || s2 == null || s1.GetType() != s2.GetType() || GetBlock(s1) is not { } t1 || GetBlock(s2) is not { } t2)
+        if (s1 is null || s2 is null || s1.GetType() != s2.GetType() || GetBlock(s1) is not { } t1 || GetBlock(s2) is not { } t2)
         {
             Message = DifferentGameGroup;
             return;

PKHeX.Core/Editing/Saves/Editors/EventWork/Diff/EventWorkDiff7b.cs

@@ -51,7 +51,7 @@ private void Diff(SAV7b s1, SAV7b s2)
 
     public IReadOnlyList<string> Summarize()
     {
-        if (S1 == null)
+        if (S1 is null)
             return [];
         var ew = S1.Blocks.EventWork;
 

PKHeX.Core/Editing/Saves/Editors/EventWork/Diff/EventWorkDiff8b.cs

@@ -53,7 +53,7 @@ private void Diff(SAV8BS s1, SAV8BS s2)
 
     public IReadOnlyList<string> Summarize()
     {
-        if (S1 == null)
+        if (S1 is null)
             return [];
 
         var fOn = SetFlags.Select(z => new FlagSummary(z).ToString());

PKHeX.Core/Editing/Saves/Editors/EventWork/EventWorkUtil.cs

@@ -57,7 +57,7 @@ public static List<EventVarGroup> GetVars(IEnumerable<string> lines, Func<int, E
                 continue;
 
             var group = list.Find(z => z.Type == type);
-            if (group == null)
+            if (group is null)
             {
                 group = new EventVarGroup(type);
                 list.Add(group);

PKHeX.Core/Editing/Saves/Management/SavePreview.cs

@@ -24,7 +24,7 @@ public SavePreview(SaveFile sav, List<INamedFolderPath> paths)
         var meta = sav.Metadata;
         var dir = meta.FileFolder;
         const string notFound = "???";
-        var parent = dir == null ? notFound : paths.Find(z => dir.StartsWith(z.Path, StringComparison.Ordinal))?.DisplayText ?? new DirectoryInfo(dir).Name;
+        var parent = dir is null ? notFound : paths.Find(z => dir.StartsWith(z.Path, StringComparison.Ordinal))?.DisplayText ?? new DirectoryInfo(dir).Name;
 
         Save = sav;
         Folder = parent;

PKHeX.Core/Editing/Saves/Slots/SlotPublisher.cs

@@ -33,7 +33,7 @@ public void NotifySlotChanged(ISlotInfo slot, SlotTouchType type, PKM pk)
 
     private void ResetView(ISlotViewer<T> sub, ISlotInfo slot, SlotTouchType type, PKM pk)
     {
-        if (Previous != null)
+        if (Previous is not null)
             sub.NotifySlotOld(Previous);
 
         if (slot is not SlotInfoBox b || sub.ViewIndex == b.Box)
@@ -42,7 +42,7 @@ private void ResetView(ISlotViewer<T> sub, ISlotInfo slot, SlotTouchType type, P
 
     public void ResetView(ISlotViewer<T> sub)
     {
-        if (Previous == null || PreviousEntity == null)
+        if (Previous is null || PreviousEntity is null)
             return;
         ResetView(sub, Previous, PreviousType, PreviousEntity);
     }

PKHeX.Core/Editing/Saves/Slots/SlotViewInfo.cs

@@ -30,5 +30,5 @@ private bool Equals(SlotViewInfo<T> other)
 
     public override bool Equals(object? obj) => ReferenceEquals(this, obj) || (obj is SlotViewInfo<T> other && Equals(other));
     public override int GetHashCode() => (Slot.GetHashCode() * 397) ^ View.GetHashCode();
-    bool IEquatable<T>.Equals(T? other) => other != null && Equals(other);
+    bool IEquatable<T>.Equals(T? other) => other is not null && Equals(other);
 }

PKHeX.Core/Editing/Showdown/ShowdownSet.cs

@@ -341,7 +341,7 @@ private string GetText(GameStrings? strings = null)
         if (Species is 0 or > MAX_SPECIES)
             return string.Empty;
 
-        if (strings != null)
+        if (strings is not null)
             Strings = strings;
 
         var result = GetSetLines();

PKHeX.Core/Legality/BulkGenerator.cs

@@ -45,7 +45,7 @@ public static List<PKM> GetLivingDex(this ITrainerInfo tr, IEnumerable<ushort> s
             for (byte f = 0; f < pi.FormCount; f++)
             {
                 var entry = tr.GetLivingEntry(pk, s, f, destType);
-                if (entry == null)
+                if (entry is null)
                     continue;
                 result.Add(entry);
             }
@@ -67,12 +67,12 @@ public static List<PKM> GetLivingDex(this ITrainerInfo tr, IEnumerable<ushort> s
         var first = EncounterMovesetGenerator.GenerateEncounters(template, tr, memory).FirstOrDefault();
         span.Clear();
         ArrayPool<ushort>.Shared.Return(moves);
-        if (first == null)
+        if (first is null)
             return null;
 
         var pk = first.ConvertToPKM(tr);
         var result = EntityConverter.ConvertToType(pk, destType, out _);
-        if (result == null)
+        if (result is null)
             return null;
 
         result.Species = species;

PKHeX.Core/Legality/Encounters/Generator/ByGeneration/EncounterGenerator3GC.cs

@@ -57,7 +57,7 @@ static bool IsTypeCompatible(IEncounterTemplate enc, PKM pk, PIDType type)
                 partial ??= z;
         }
 
-        if (partial != null)
+        if (partial is not null)
         {
             info.ManualFlag = EncounterYieldFlag.InvalidPIDIV;
             yield return partial;

PKHeX.Core/Legality/Encounters/Generator/Search/Dirtied/EncounterEnumerator8bSWSH.cs

@@ -143,7 +143,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
             case YieldState.End:

PKHeX.Core/Legality/Encounters/Generator/Search/Dirtied/EncounterEnumerator9SWSH.cs

@@ -163,7 +163,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator1.cs

@@ -134,7 +134,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator2.cs

@@ -177,7 +177,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator3.cs

@@ -248,7 +248,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator3GC.cs

@@ -94,7 +94,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator4.cs

@@ -232,7 +232,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator5.cs

@@ -250,7 +250,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator6.cs

@@ -204,7 +204,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator7.cs

@@ -203,7 +203,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator7GG.cs

@@ -136,7 +136,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator7GO.cs

@@ -54,7 +54,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator8.cs

@@ -203,7 +203,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator8GO.cs

@@ -75,7 +75,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator8a.cs

@@ -78,7 +78,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator8b.cs

@@ -148,7 +148,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Generator/Search/EncounterEnumerator9.cs

@@ -170,7 +170,7 @@ public bool MoveNext()
 
             case YieldState.Fallback:
                 State = YieldState.End;
-                if (Deferred != null)
+                if (Deferred is not null)
                     return SetCurrent(Deferred, Rating);
                 break;
         }

PKHeX.Core/Legality/Encounters/Templates/Gen8/EncounterStatic8U.cs

@@ -44,10 +44,7 @@ public static EncounterStatic8U Read(ReadOnlySpan<byte> data)
     protected override void SetTrainerName(ReadOnlySpan<char> name, PK8 pk)
     {
         if (ShouldHaveScientistTrash)
-        {
-            var scientist = GetScientistName(pk.Language);
-            pk.SetString(pk.OriginalTrainerTrash, scientist, scientist.Length, StringConverterOption.None);
-        }
+            base.SetTrainerName(GetScientistName(pk.Language), pk);
         base.SetTrainerName(name, pk);
     }
 

PKHeX.Core/Legality/Encounters/Verifiers/MysteryGiftVerifier.cs

@@ -61,7 +61,7 @@ public static CheckResult VerifyGift(PKM pk, MysteryGift g)
     private static bool TryGetRestriction(MysteryGift g, out MysteryGiftRestriction val)
     {
         var restrict = RestrictionSet[g.Generation];
-        if (restrict != null)
+        if (restrict is not null)
             return restrict.TryGetValue(g.GetHashCode(), out val);
         val = MysteryGiftRestriction.None;
         return false;

PKHeX.Core/Legality/Restrictions/WordFilter/WordFilter3DS.cs

@@ -46,7 +46,7 @@ public static bool IsFiltered(ReadOnlySpan<char> message, [NotNullWhen(true)] ou
 
         // Check dictionary
         if (Lookup.TryGetValue(message, out regMatch))
-            return regMatch != null;
+            return regMatch is not null;
 
         // not in dictionary, check patterns
         if (WordFilter.TryMatch(message, Regexes, out regMatch))

PKHeX.Core/Legality/Restrictions/WordFilter/WordFilterNX.cs

@@ -39,7 +39,7 @@ public static bool IsFiltered(ReadOnlySpan<char> message, [NotNullWhen(true)] ou
 
         // Check dictionary
         if (Lookup.TryGetValue(message, out regMatch))
-            return regMatch != null;
+            return regMatch is not null;
 
         // not in dictionary, check patterns
         if (WordFilter.TryMatch(message, Regexes, out regMatch))

PKHeX.Core/Legality/Verifiers/NicknameVerifier.cs

@@ -301,6 +301,8 @@ private static bool IsMatch45(ReadOnlySpan<char> nickname, ushort species, ReadO
 
     private static bool IsMatchUpper45(ReadOnlySpan<char> nickname, ReadOnlySpan<char> expect)
     {
+        if (nickname.Length != expect.Length)
+            return false;
         for (int i = 0; i < expect.Length; i++)
         {
             if (nickname[i] != char.ToUpperInvariant(expect[i]))
@@ -311,10 +313,10 @@ private static bool IsMatchUpper45(ReadOnlySpan<char> nickname, ReadOnlySpan<cha
 
     private static void VerifyNicknameEgg(LegalityAnalysis data)
     {
-        var Info = data.Info;
         var pk = data.Entity;
+        var enc = data.Info.EncounterMatch;
 
-        bool flagState = EggStateLegality.IsNicknameFlagSet(Info.EncounterMatch, pk);
+        bool flagState = EggStateLegality.IsNicknameFlagSet(enc, pk);
         if (pk.IsNicknamed != flagState)
             data.AddLine(GetInvalid(flagState ? LNickFlagEggYes : LNickFlagEggNo, CheckIdentifier.Egg));
 
@@ -324,7 +326,7 @@ private static void VerifyNicknameEgg(LegalityAnalysis data)
 
         if (pk.Format == 2 && !SpeciesName.IsNicknamedAnyLanguage(0, nickname, 2))
             data.AddLine(GetValid(LNickMatchLanguageEgg, CheckIdentifier.Egg));
-        else if (!nickname.SequenceEqual(SpeciesName.GetEggName(pk.Language, Info.Generation)))
+        else if (!nickname.SequenceEqual(SpeciesName.GetEggName(pk.Language, enc.Generation)))
             data.AddLine(GetInvalid(LNickMatchLanguageEggFail, CheckIdentifier.Egg));
         else
             data.AddLine(GetValid(LNickMatchLanguageEgg, CheckIdentifier.Egg));

PKHeX.Core/Legality/Verifiers/TrainerNameVerifier.cs

@@ -188,17 +188,10 @@ public static bool ContainsTooManyNumbers(ReadOnlySpan<char> str, int originalGe
 
     private static int GetNumberCount(ReadOnlySpan<char> str)
     {
-        static bool IsNumber(char c)
-        {
-            if (c >= '０')
-                return c <= '９';
-            return (uint)(c - '0') <= 9;
-        }
-
         int ctr = 0;
         foreach (var c in str)
         {
-            if (IsNumber(c))
+            if (char.IsNumber(c))
                 ++ctr;
         }
         return ctr;

PKHeX.Core/MysteryGifts/MysteryUtil.cs

@@ -26,7 +26,7 @@ public static IEnumerable<MysteryGift> GetGiftsFromFolder(string folder)
 
             var data = File.ReadAllBytes(file);
             var gift = MysteryGift.GetMysteryGift(data, fi.Extension);
-            if (gift != null)
+            if (gift is not null)
                 yield return gift;
         }
     }

PKHeX.Core/PKM/HOME/GameDataPA8.cs

@@ -144,7 +144,7 @@ public PA8 ConvertToPKM(PKH pkh)
             return null;
 
         var result = CreateInternal(pkh);
-        if (result == null)
+        if (result is null)
             return null;
 
         result.PopulateFromCore(pkh);
@@ -154,7 +154,7 @@ public PA8 ConvertToPKM(PKH pkh)
     private static GameDataPA8? CreateInternal(PKH pkh)
     {
         var side = GetNearestNeighbor(pkh);
-        if (side == null)
+        if (side is null)
             return null;
 
         var result = new GameDataPA8();

PKHeX.Core/PKM/HOME/GameDataPB7.cs

@@ -158,7 +158,7 @@ public PB7 ConvertToPKM(PKH pkh)
         // There isn't an actual preference since this format cannot naturally backwards transfer.
         // Just pick out the first one.
         var result = CreateInternal(pkh);
-        if (result == null)
+        if (result is null)
             return null;
 
         result.PopulateFromCore(pkh);
@@ -168,7 +168,7 @@ public PB7 ConvertToPKM(PKH pkh)
     private static GameDataPB7? CreateInternal(PKH pkh)
     {
         var side = GetNearestNeighbor(pkh);
-        if (side == null)
+        if (side is null)
             return null;
 
         var ball = side.Ball;

PKHeX.Core/PKM/HOME/GameDataPB8.cs

@@ -94,7 +94,7 @@ public PB8 ConvertToPKM(PKH pkh)
     public static GameDataPB8? TryCreate(PKH pkh)
     {
         var side = GetNearestNeighbor(pkh);
-        if (side == null)
+        if (side is null)
             return null;
 
         var result = new GameDataPB8();

PKHeX.Core/PKM/HOME/GameDataPK9.cs

@@ -162,7 +162,7 @@ public PK9 ConvertToPKM(PKH pkh)
             return null;
 
         var result = CreateInternal(pkh);
-        if (result == null)
+        if (result is null)
             return null;
 
         result.PopulateFromCore(pkh);
@@ -172,7 +172,7 @@ public PK9 ConvertToPKM(PKH pkh)
     private static GameDataPK9? CreateInternal(PKH pkh)
     {
         var side = GetNearestNeighbor(pkh);
-        if (side == null)
+        if (side is null)
             return null;
 
         var result = new GameDataPK9();

PKHeX.Core/PKM/Searching/SearchSettings.cs

@@ -170,7 +170,7 @@ private bool SearchIntermediate(PKM pk)
             return false;
         if (HiddenPowerType > -1 && pk.HPType != HiddenPowerType)
             return false;
-        if (SearchShiny != null && pk.IsShiny != SearchShiny)
+        if (SearchShiny is not null && pk.IsShiny != SearchShiny)
             return false;
 
         if (IVType > 0 && !SearchUtil.SatisfiesFilterIVs(pk, IVType))
@@ -183,11 +183,11 @@ private bool SearchIntermediate(PKM pk)
 
     private bool SearchComplex(PKM pk)
     {
-        if (SearchEgg != null && !FilterResultEgg(pk))
+        if (SearchEgg is not null && !FilterResultEgg(pk))
             return false;
         if (Level is { } x and not 0 && !SearchUtil.SatisfiesFilterLevel(pk, SearchLevel, x))
             return false;
-        if (SearchLegal != null && new LegalityAnalysis(pk).Valid != SearchLegal)
+        if (SearchLegal is not null && new LegalityAnalysis(pk).Valid != SearchLegal)
             return false;
         if (BatchFilters.Count != 0 && !SearchUtil.SatisfiesFilterBatchInstruction(pk, BatchFilters))
             return false;
@@ -199,7 +199,7 @@ private bool FilterResultEgg(PKM pk)
     {
         if (SearchEgg == false)
             return !pk.IsEgg;
-        if (ESV != null)
+        if (ESV is not null)
             return pk.IsEgg && pk.PSV == ESV;
         return pk.IsEgg;
     }

PKHeX.Core/PKM/Util/Conversion/EntityConverter.cs

@@ -136,7 +136,7 @@ public static bool IsConvertibleToFormat(PKM pk, byte format)
         while (true)
         {
             entity = IntermediaryConvert(entity, destType, ref result);
-            if (entity == null) // fail convert
+            if (entity is null) // fail convert
                 return null;
             if (entity.GetType() == destType) // finish convert
                 return entity;
@@ -308,7 +308,7 @@ public static bool TryMakePKMCompatible(PKM pk, PKM target, out EntityConverterR
             return false;
         }
         var convert = ConvertToType(pk, target.GetType(), out result);
-        if (convert == null)
+        if (convert is null)
         {
             converted = target;
             return false;

PKHeX.Core/Saves/Encryption/Providers/IAesCryptographyProvider.cs

@@ -38,7 +38,7 @@ public AesSession(byte[] key, CipherMode mode, PaddingMode padding, byte[]? iv)
                 _aes.Mode = mode;
                 _aes.Padding = padding;
                 _aes.Key = key;
-                if (iv != null)
+                if (iv is not null)
                     _aes.IV = iv;
             }
 

PKHeX.Core/Saves/Encryption/SwishCrypto/SCBlockMetadata.cs

@@ -74,7 +74,7 @@ private string GetBlockHint(SCBlock z, int index)
         var blockName = GetBlockName(z, out _);
         var isBool = z.Type.IsBoolean();
         var type = (isBool ? "Bool" : z.Type.ToString());
-        if (blockName != null)
+        if (blockName is not null)
             return $"*{type} {blockName}";
         var result = $"{z.Key:X8} - {index:0000} {type}";
         if (z.Type is SCTypeCode.Object or SCTypeCode.Array)

PKHeX.Core/Saves/SAV3RSBox.cs

@@ -171,7 +171,7 @@ private int GetBoxWallpaperOffset(int box)
     public string GetBoxName(int box)
     {
         // Tweaked for the 1-30/31-60 box showing
-        var dir = box % 2 == 0 ? "◖" : "◗";
+        var dir = box % 2 == 0 ? "◖ " : " ◗";
         string boxName = $"[{dir}] ";
         box /= 2;
 
@@ -187,7 +187,7 @@ public string GetBoxName(int box)
     public void SetBoxName(int box, ReadOnlySpan<char> value)
     {
         var span = GetBoxNameSpan(box);
-        if (value == BoxDetailNameExtensions.GetDefaultBoxNameCaps(box))
+        if (value.SequenceEqual(BoxDetailNameExtensions.GetDefaultBoxNameCaps(box)))
         {
             span.Clear();
             return;

PKHeX.Core/Saves/SAV3XD.cs

@@ -161,7 +161,7 @@ private byte[] GetInnerData()
 
         // Put save slot back in original save data
         var destOffset = SLOT_START + (SaveIndex * SLOT_SIZE);
-        byte[] dest = MemoryCard != null ? MemoryCard.ReadSaveGameData().ToArray() : (byte[])BAK.Clone();
+        byte[] dest = MemoryCard is not null ? MemoryCard.ReadSaveGameData().ToArray() : (byte[])BAK.Clone();
         var destSpan = dest.AsSpan(destOffset, Data.Length);
 
         // Get updated save slot data

PKHeX.Core/Saves/SaveFile.cs

@@ -726,7 +726,7 @@ public int ClearBoxes(int BoxStart = 0, int BoxEnd = -1, Func<PKM, bool>? delete
                 var ofs = GetBoxSlotOffset(i, p);
                 if (!IsPKMPresent(storage[ofs..]))
                     continue;
-                if (deleteCriteria != null)
+                if (deleteCriteria is not null)
                 {
                     var pk = GetBoxSlotAtIndex(i, p);
                     if (!deleteCriteria(pk))

PKHeX.Core/Saves/SaveFileMetadata.cs

@@ -175,7 +175,7 @@ public string GetSuggestedExtension()
     {
         var sav = SAV;
         var fn = sav.Metadata.FileName;
-        if (fn != null)
+        if (fn is not null)
             return Path.GetExtension(fn);
 
         if ((sav.Generation is 4 or 5) && sav.Metadata.HasFooter)

PKHeX.Core/Saves/Substructures/Gen9/RaidSevenStar9.cs

@@ -34,7 +34,7 @@ public uint Identifier
         set
         {
             captured.Identifier = value;
-            if (defeated != null)
+            if (defeated is not null)
                 defeated.Identifier = value;
         }
     }
@@ -52,7 +52,7 @@ public bool Defeated
         get => defeated?.Defeated ?? captured.Defeated;
         set
         {
-            if (defeated != null)
+            if (defeated is not null)
                 defeated.Defeated = value;
             else
                 captured.Defeated = value;

PKHeX.Core/Saves/Substructures/Mail/Mail4.cs

@@ -13,8 +13,8 @@ public sealed class Mail4 : MailDetail
 
     public Mail4(byte? lang, byte? version) : base(new byte[SIZE])
     {
-        if (lang != null) AuthorLanguage = (byte)lang;
-        if (version != null) AuthorVersion = (byte)version;
+        if (lang is not null) AuthorLanguage = (byte)lang;
+        if (version is not null) AuthorVersion = (byte)version;
         ResetData();
     }
 

PKHeX.Core/Saves/Substructures/Mail/Mail5.cs

@@ -11,8 +11,8 @@ public sealed class Mail5 : MailDetail
 
     public Mail5(byte? lang, byte? version) : base(new byte[SIZE])
     {
-        if (lang != null) AuthorLanguage = (byte)lang;
-        if (version != null) AuthorVersion = (byte)version;
+        if (lang is not null) AuthorLanguage = (byte)lang;
+        if (version is not null) AuthorVersion = (byte)version;
         ResetData();
     }
 

PKHeX.Core/Saves/Util/SaveExtensions.cs

@@ -49,7 +49,7 @@ private static List<string> GetSaveFileErrata(this SaveFile sav, PKM pk, IBasicS
                 msg = MsgIndexItemGame;
             else if (!pk.CanHoldItem(sav.HeldItems))
                 msg = MsgIndexItemHeld;
-            if (msg != null)
+            if (msg is not null)
             {
                 var itemstr = GameInfo.Strings.GetItemStrings(pk.Context, pk.Version);
                 errata.Add($"{msg} {(held >= itemstr.Length ? held.ToString() : itemstr[held])}");
@@ -134,7 +134,7 @@ public static IEnumerable<PKM> GetCompatible(this SaveFile sav, IEnumerable<PKM>
         foreach (var temp in pks)
         {
             var pk = EntityConverter.ConvertToType(temp, savtype, out var c);
-            if (pk == null)
+            if (pk is null)
             {
                 Debug.WriteLine(c.GetDisplayString(temp, savtype));
                 continue;

PKHeX.Core/Saves/Util/SaveFinder.cs

@@ -119,7 +119,7 @@ public static IEnumerable<SaveFile> GetSaveFiles(IReadOnlyList<string> drives, b
         foreach (var s in byMostRecent)
         {
             var sav = SaveUtil.GetVariantSAV(s);
-            if (sav != null)
+            if (sav is not null)
                 yield return sav;
         }
     }

PKHeX.Core/Saves/Util/SaveUtil.cs

@@ -658,13 +658,13 @@ private static GameVersion GetIsG9SAV(ReadOnlySpan<byte> data)
                 continue;
 
             var custom = h.ReadSaveFile(data, path);
-            if (custom != null)
+            if (custom is not null)
                 return custom;
         }
 #endif
 
         var sav = GetVariantSAVInternal(data);
-        if (sav != null)
+        if (sav is not null)
             return sav;
 
 #if !EXCLUDE_EMULATOR_FORMATS
@@ -674,11 +674,11 @@ private static GameVersion GetIsG9SAV(ReadOnlySpan<byte> data)
                 continue;
 
             var split = h.TrySplit(data);
-            if (split == null)
+            if (split is null)
                 continue;
 
             sav = GetVariantSAVInternal(split.Data);
-            if (sav == null)
+            if (sav is null)
                 continue;
 
             var meta = sav.Metadata;
@@ -757,7 +757,7 @@ private static GameVersion GetIsG9SAV(ReadOnlySpan<byte> data)
             return null;
 
         var split = DolphinHandler.TrySplit(memory.Span);
-        var data = split != null ? split.Data : memory.ToArray();
+        var data = split is not null ? split.Data : memory.ToArray();
 
         SaveFile sav;
         switch (memCard.SelectedGameVersion)
@@ -771,7 +771,7 @@ private static GameVersion GetIsG9SAV(ReadOnlySpan<byte> data)
             default: return null;
         }
 
-        if (split != null)
+        if (split is not null)
             sav.Metadata.SetExtraInfo(split.Header, split.Footer, split.Handler);
         return sav;
     }

PKHeX.Core/Saves/Util/StorageUtil.cs

@@ -94,7 +94,7 @@ public static int FindNextValidIndex<T>(Span<T> dest, Func<int, bool> skip, int
             if ((uint)ctr >= dest.Length)
                 return -1;
             var exist = dest[ctr];
-            if (exist == null || !skip(ctr))
+            if (exist is null || !skip(ctr))
                 return ctr;
             ctr++;
         }

PKHeX.Core/Util/ComboItemUtil.cs

@@ -140,9 +140,9 @@ private sealed class FunctorComparer<T>(Comparison<T> Comparison) : IComparer<T>
     {
         public int Compare(T? x, T? y)
         {
-            if (x == null)
-                return y == null ? 0 : -1;
-            return y == null ? 1 : Comparison(x, y);
+            if (x is null)
+                return y is null ? 0 : -1;
+            return y is null ? 1 : Comparison(x, y);
         }
     }
 }

PKHeX.Core/Util/FileUtil.cs

@@ -172,7 +172,7 @@ public static bool IsFileTooBig(long length)
     public static bool TryGetSAV(byte[] data, [NotNullWhen(true)] out SaveFile? sav)
     {
         sav = SaveUtil.GetVariantSAV(data);
-        return sav != null;
+        return sav is not null;
     }
 
     /// <summary>
@@ -221,7 +221,7 @@ public static bool TryGetPKM(byte[] data, [NotNullWhen(true)] out PKM? pk, ReadO
         }
         var format = EntityFileExtension.GetContextFromExtension(ext, sav?.Context ?? EntityContext.Gen6);
         pk = EntityFormat.GetFromBytes(data, prefer: format);
-        return pk != null;
+        return pk is not null;
     }
 
     /// <summary>
@@ -277,7 +277,7 @@ private static bool IsNoDataPresent(ReadOnlySpan<byte> data)
     public static bool TryGetBattleVideo(byte[] data, [NotNullWhen(true)] out IBattleVideo? bv)
     {
         bv = BattleVideo.GetVariantBattleVideo(data);
-        return bv != null;
+        return bv is not null;
     }
 
     /// <summary>
@@ -292,7 +292,7 @@ public static bool TryGetMysteryGift(byte[] data, [NotNullWhen(true)] out Myster
         mg = ext.Length == 0
             ? MysteryGift.GetMysteryGift(data)
             : MysteryGift.GetMysteryGift(data, ext);
-        return mg != null;
+        return mg is not null;
     }
 
     /// <summary>
@@ -328,7 +328,7 @@ public static string GetPKMTempFileName(PKM pk, bool encrypt)
         var ext = fi.Extension;
         var mg = MysteryGift.GetMysteryGift(data, ext);
         var gift = mg?.ConvertToPKM(sav);
-        if (gift != null)
+        if (gift is not null)
             return gift;
         _ = TryGetPKM(data, out var pk, ext, sav);
         return pk;

PKHeX.Core/Util/Localization/LocalizeUtil.cs

@@ -13,7 +13,7 @@ public static class LocalizeUtil
     public static void InitializeStrings(string lang, SaveFile? sav = null, bool hax = false)
     {
         var str = GameInfo.Strings = GameInfo.GetStrings(lang);
-        if (sav != null)
+        if (sav is not null)
             GameInfo.FilteredSources = new FilteredGameDataSource(sav, GameInfo.Sources, hax);
 
         // Update Legality Analysis strings

PKHeX.Core/Util/NetUtil.cs

@@ -12,7 +12,7 @@ public static class NetUtil
         try
         {
             var stream = GetStreamFromURL(url);
-            if (stream == null)
+            if (stream is null)
                 return null;
 
             using var reader = new StreamReader(stream);

PKHeX.Core/Util/ReflectUtil.cs

@@ -143,7 +143,7 @@ public static IEnumerable<PropertyInfo> GetAllProperties(this TypeInfo typeInfo)
 
     public static IEnumerable<TypeInfo> GetAllTypeInfo(this TypeInfo? typeInfo)
     {
-        while (typeInfo != null)
+        while (typeInfo is not null)
         {
             yield return typeInfo;
             typeInfo = typeInfo.BaseType?.GetTypeInfo();
@@ -168,12 +168,12 @@ public static bool TryGetPropertyInfo(this TypeInfo typeInfo, string name, [NotN
         foreach (var t in typeInfo.GetAllTypeInfo())
         {
             pi = t.GetDeclaredProperty(name);
-            if (pi != null)
+            if (pi is not null)
                 return true;
             foreach (var i in t.ImplementedInterfaces)
             {
                 pi = i.GetTypeInfo().GetDeclaredProperty(name);
-                if (pi != null)
+                if (pi is not null)
                     return true;
             }
         }

PKHeX.Drawing.PokeSprite/Builder/SpriteBuilder.cs

@@ -170,13 +170,13 @@ private Bitmap GetBaseImageFallback(ushort species, byte form, byte gender, uint
         if (shiny) // try again without shiny
         {
             var img = GetBaseImageDefault(species, form, gender, formarg, false, context);
-            if (img != null)
+            if (img is not null)
                 return img;
         }
 
         // try again without form
         var baseImage = (Bitmap?)Resources.ResourceManager.GetObject(GetSpriteStringSpeciesOnly(species));
-        if (baseImage == null) // failed again
+        if (baseImage is null) // failed again
             return Unknown;
         return ImageUtil.LayerImage(baseImage, Unknown, 0, 0, UnknownFormTransparency);
     }

PKHeX.WinForms/Controls/PKM Editor/CatchRate.cs

@@ -25,7 +25,7 @@ private void Reset(object sender, EventArgs e)
         if (Entity is null)
             return;
         var sav = WinFormsUtil.FindFirstControlOfType<IMainEditor>(this)?.RequestSaveFile;
-        if (sav == null)
+        if (sav is null)
             return;
         NUD_CatchRate.Value = CatchRateApplicator.GetSuggestedCatchRate(Entity, sav);
     }

PKHeX.WinForms/Controls/PKM Editor/PKMEditor.cs

@@ -827,7 +827,7 @@ private static string GetMoveListPrint(Span<ushort> moves, ReadOnlySpan<string>
     private bool SetSuggestedMetLocation(bool silent = false)
     {
         var encounter = EncounterSuggestion.GetSuggestedMetInfo(Entity);
-        if (encounter == null || (Entity.Format >= 3 && encounter.Location == 0))
+        if (encounter is null || (Entity.Format >= 3 && encounter.Location == 0))
         {
             if (!silent)
                 WinFormsUtil.Alert(MsgPKMSuggestionNone);
@@ -1660,7 +1660,7 @@ private void ValidateComboBox(ComboBox cb)
     {
         if (cb.Text.Length == 0 && cb.Items.Count > 0)
             cb.SelectedIndex = 0;
-        else if (cb.SelectedValue == null)
+        else if (cb.SelectedValue is null)
             cb.BackColor = Draw.InvalidSelection;
         else
             cb.ResetBackColor();

PKHeX.WinForms/Controls/PKM Editor/SizeCP.cs

@@ -36,7 +36,7 @@ public void LoadPKM(PKM entity)
         ss = entity as IScaledSize;
         sv = entity as IScaledSizeValue;
         scale = entity as IScaledSize3;
-        if (ss == null)
+        if (ss is null)
             return;
         TryResetStats();
     }
@@ -63,23 +63,23 @@ private void ResetCalculatedStats()
     private void LoadStoredValues()
     {
         Loading = true;
-        if (ss != null)
+        if (ss is not null)
         {
             if (NUD_HeightScalar.Focused || NUD_WeightScalar.Focused)
                 CHK_Auto.Focus();
             NUD_HeightScalar.Value = ss.HeightScalar;
             NUD_WeightScalar.Value = ss.WeightScalar;
         }
-        if (sv != null)
+        if (sv is not null)
         {
             TB_HeightAbs.Text = GetString(sv.HeightAbsolute);
             TB_WeightAbs.Text = GetString(sv.WeightAbsolute);
         }
-        if (scale != null)
+        if (scale is not null)
         {
             NUD_Scale.Value = scale.Scale;
         }
-        if (pk != null)
+        if (pk is not null)
         {
             MT_CP.Text = Math.Min(65535, pk.Stat_CP).ToString();
         }
@@ -97,13 +97,13 @@ private void UpdateFlagState(object sender, EventArgs e)
 
     private void MT_CP_TextChanged(object sender, EventArgs e)
     {
-        if (pk != null && int.TryParse(MT_CP.Text, out var cp))
+        if (pk is not null && int.TryParse(MT_CP.Text, out var cp))
             pk.Stat_CP = Math.Min(65535, cp);
     }
 
     private void NUD_HeightScalar_ValueChanged(object sender, EventArgs e)
     {
-        if (ss != null)
+        if (ss is not null)
         {
             if (!Loading)
             {
@@ -117,7 +117,7 @@ private void NUD_HeightScalar_ValueChanged(object sender, EventArgs e)
             SetLabelColorHeightWeight(label);
         }
 
-        if (!CHK_Auto.Checked || Loading || sv == null)
+        if (!CHK_Auto.Checked || Loading || sv is null)
             return;
         sv.ResetHeight();
         sv.ResetWeight();
@@ -127,7 +127,7 @@ private void NUD_HeightScalar_ValueChanged(object sender, EventArgs e)
 
     private void NUD_WeightScalar_ValueChanged(object sender, EventArgs e)
     {
-        if (ss != null)
+        if (ss is not null)
         {
             if (!Loading)
                 ss.WeightScalar = (byte)NUD_WeightScalar.Value;
@@ -137,7 +137,7 @@ private void NUD_WeightScalar_ValueChanged(object sender, EventArgs e)
             SetLabelColorHeightWeight(label);
         }
 
-        if (!CHK_Auto.Checked || Loading || sv == null)
+        if (!CHK_Auto.Checked || Loading || sv is null)
             return;
         sv.ResetWeight();
         TB_WeightAbs.Text = GetString(sv.WeightAbsolute);
@@ -145,7 +145,7 @@ private void NUD_WeightScalar_ValueChanged(object sender, EventArgs e)
 
     private void NUD_Scale_ValueChanged(object sender, EventArgs e)
     {
-        if (scale != null)
+        if (scale is not null)
         {
             if (!Loading)
             {
@@ -174,7 +174,7 @@ private void SetLabelColorHeightWeight(Control label)
 
     private void TB_HeightAbs_TextChanged(object sender, EventArgs e)
     {
-        if (sv == null || Loading)
+        if (sv is null || Loading)
             return;
         if (CHK_Auto.Checked)
             sv.ResetHeight();
@@ -184,7 +184,7 @@ private void TB_HeightAbs_TextChanged(object sender, EventArgs e)
 
     private void TB_WeightAbs_TextChanged(object sender, EventArgs e)
     {
-        if (sv == null || Loading)
+        if (sv is null || Loading)
             return;
         if (CHK_Auto.Checked)
             sv.ResetWeight();

PKHeX.WinForms/Controls/SAV Editor/BitmapAnimator.cs

@@ -34,7 +34,7 @@ public sealed class BitmapAnimator : IDisposable
 
     public void Stop()
     {
-        if (pb == null || !Enabled)
+        if (pb is null || !Enabled)
             return;
 
         lock (Lock)
@@ -81,7 +81,7 @@ private void TimerElapsed(object? sender, ElapsedEventArgs? elapsedEventArgs)
             if (!Enabled)
                 return;
 
-            if (pb == null)
+            if (pb is null)
                 return;
             try { pb.BackgroundImage = GetFrame(frameIndex); } // drawing GDI can be silly sometimes #2072
             catch (AccessViolationException ex) { System.Diagnostics.Debug.WriteLine(ex.Message); }
@@ -93,7 +93,7 @@ private Image GetFrame(int frameIndex)
         var cache = GlowCache;
         ArgumentNullException.ThrowIfNull(cache);
         var frame = cache[frameIndex];
-        if (frame != null)
+        if (frame is not null)
             return frame;
 
         var elapsedFraction = (double)frameIndex / GlowInterval;
@@ -109,9 +109,9 @@ private Image GetFrame(int frameIndex)
         frameSpan.Clear();
         ArrayPool<byte>.Shared.Return(frameData);
 
-        if (ExtraLayer != null)
+        if (ExtraLayer is not null)
             frame = ImageUtil.LayerImage(frame, ExtraLayer, 0, 0);
-        if (OriginalBackground != null)
+        if (OriginalBackground is not null)
             frame = ImageUtil.LayerImage(OriginalBackground, frame, 0, 0);
         return cache[frameIndex] = frame;
     }

PKHeX.WinForms/Controls/SAV Editor/ContextMenuSAV.cs

@@ -123,7 +123,7 @@ private void MenuOpening(object sender, CancelEventArgs e)
         bool canView = !info.IsEmpty() || Main.HaX;
         bool canSet = info.CanWriteTo();
         bool canDelete = canSet && canView;
-        bool canLegality = (ModifierKeys == Keys.Control || Main.Settings.Display.SlotLegalityAlwaysVisible) && canView && RequestEditorLegality != null;
+        bool canLegality = (ModifierKeys == Keys.Control || Main.Settings.Display.SlotLegalityAlwaysVisible) && canView && RequestEditorLegality is not null;
 
         ToggleItem(mnuView, canView);
         ToggleItem(mnuSet, canSet);

PKHeX.WinForms/Controls/SAV Editor/SAVEditor.Designer.cs

@@ -13,7 +13,7 @@ partial class SAVEditor
         /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
         protected override void Dispose(bool disposing)
         {
-            if (disposing && (components != null))
+            if (disposing && (components is not null))
             {
                 components.Dispose();
             }

PKHeX.WinForms/Controls/SAV Editor/SAVEditor.cs

@@ -287,7 +287,7 @@ private void ResetDaycare()
                 L_SlotOccupied[i].Text = $"{i + 1}: ✘";
                 var pb = UpdateSlot(i);
                 var current = pb.Image;
-                if (current != null)
+                if (current is not null)
                     pb.Image = ImageUtil.ChangeOpacity(current, 0.6);
             }
         }
@@ -474,7 +474,7 @@ private void ClickBoxDouble(object sender, MouseEventArgs e)
         if (M.Boxes.Count > 1) // subview open
         {
             var z = M.Boxes[1].ParentForm;
-            if (z == null)
+            if (z is null)
                 return;
             z.CenterToForm(ParentForm);
             z.BringToFront();
@@ -696,7 +696,7 @@ private void B_OtherSlots_Click(object sender, EventArgs e)
         void TryOpen(SaveFile sav, IReadOnlyList<SlotGroup> g)
         {
             var form = WinFormsUtil.FirstFormOfType<SAV_GroupViewer>();
-            if (form != null)
+            if (form is not null)
             {
                 form.CenterToForm(ParentForm);
             }
@@ -1059,7 +1059,7 @@ public bool LoadBoxes(out string result, string? path = null)
         if (!SAV.HasBox)
             return false;
 
-        if (path == null && !IsFolderPath(out path))
+        if (path is null && !IsFolderPath(out path))
         {
             result = path;
             return false;
@@ -1121,7 +1121,7 @@ private void ToggleViewReset()
                 if (height > allowed)
                 {
                     var form = FindForm();
-                    if (form != null)
+                    if (form is not null)
                         form.Height += height - allowed;
                 }
             }

PKHeX.WinForms/Controls/SAV Editor/SlotChangeManager.cs

@@ -47,7 +47,7 @@ public void MouseLeave(object? sender, EventArgs e)
 
     public void MouseClick(object? sender, MouseEventArgs e)
     {
-        if (sender == null)
+        if (sender is null)
             return;
         if (!Drag.Info.DragDropInProgress)
             SE.ClickSlot(sender, e);
@@ -55,7 +55,7 @@ public void MouseClick(object? sender, MouseEventArgs e)
 
     public void MouseUp(object? sender, MouseEventArgs e)
     {
-        if (sender == null)
+        if (sender is null)
             return;
         if (e.Button == MouseButtons.Left)
             Drag.Info.LeftMouseIsDown = false;
@@ -64,7 +64,7 @@ public void MouseUp(object? sender, MouseEventArgs e)
 
     public void MouseDown(object? sender, MouseEventArgs e)
     {
-        if (sender == null)
+        if (sender is null)
             return;
         if (e.Button == MouseButtons.Left)
         {
@@ -75,7 +75,7 @@ public void MouseDown(object? sender, MouseEventArgs e)
 
     public void QueryContinueDrag(object? sender, QueryContinueDragEventArgs e)
     {
-        if (sender == null)
+        if (sender is null)
             return;
         if (e.Action != DragAction.Cancel && e.Action != DragAction.Drop)
             return;
@@ -85,11 +85,11 @@ public void QueryContinueDrag(object? sender, QueryContinueDragEventArgs e)
 
     public void DragEnter(object? sender, DragEventArgs e)
     {
-        if (sender == null)
+        if (sender is null)
             return;
         if ((e.AllowedEffect & DragDropEffects.Copy) != 0) // external file
             e.Effect = DragDropEffects.Copy;
-        else if (e.Data != null) // within
+        else if (e.Data is not null) // within
             e.Effect = DragDropEffects.Move;
 
         if (Drag.Info.DragDropInProgress)
@@ -115,7 +115,7 @@ public void MouseMove(object? sender, MouseEventArgs e)
             return;
 
         // Abort if there is no Pokémon in the given slot.
-        if (pb.Image == null)
+        if (pb.Image is null)
             return;
         bool encrypt = Control.ModifierKeys == Keys.Control;
         HandleMovePKM(pb, encrypt);
@@ -217,7 +217,7 @@ private bool TryMakeDragDropPKM(PictureBox pb, ReadOnlySpan<byte> data, string n
         // Thread Blocks on DoDragDrop
         Drag.Info.CurrentPath = newfile;
         var result = pb.DoDragDrop(new DataObject(DataFormats.FileDrop, new[] { newfile }), DragDropEffects.Copy);
-        var external = Drag.Info.Destination == null || result != DragDropEffects.Link;
+        var external = Drag.Info.Destination is null || result != DragDropEffects.Link;
         if (external || Drag.Info.SameLocation) // not dropped to another box slot, restore img
         {
             pb.Image = img;
@@ -228,7 +228,7 @@ private bool TryMakeDragDropPKM(PictureBox pb, ReadOnlySpan<byte> data, string n
 
         if (result == DragDropEffects.Copy) // viewed in tabs or cloned
         {
-            if (Drag.Info.Destination == null) // apply 'view' highlight
+            if (Drag.Info.Destination is null) // apply 'view' highlight
                 Env.Slots.Get(Drag.Info.Source!.Slot);
             return false;
         }
@@ -261,7 +261,7 @@ private void HandleDropPKM(PictureBox pb, DragEventArgs? e, DropModifier mod)
 
         var dest = Drag.Info.Destination;
 
-        if (Drag.Info.Source == null) // external source
+        if (Drag.Info.Source is null) // external source
         {
             bool badDest = !dest!.CanWriteTo();
             if (!TryLoadFiles(files, e, badDest))
@@ -289,14 +289,14 @@ private bool TryLoadFiles(ReadOnlySpan<string> files, DragEventArgs e, bool badD
         var sav = Drag.Info.Destination!.View.SAV;
         var path = files[0];
         var temp = FileUtil.GetSingleFromPath(path, sav);
-        if (temp == null)
+        if (temp is null)
         {
             Drag.RequestDD(this, e); // pass through
             return true; // treat as handled
         }
 
         var pk = EntityConverter.ConvertToType(temp, sav.PKMType, out var result);
-        if (pk == null)
+        if (pk is null)
         {
             var c = result.GetDisplayString(temp, sav.PKMType);
             WinFormsUtil.Error(c);
@@ -340,7 +340,7 @@ private bool TrySetPKMDestination(PictureBox pb, DropModifier mod)
         if (msg != WriteBlockedMessage.None)
             return false;
 
-        if (Drag.Info.Source != null)
+        if (Drag.Info.Source is not null)
             TrySetPKMSource(mod);
 
         // Copy from temp to destination slot.
@@ -354,7 +354,7 @@ private bool TrySetPKMSource(DropModifier mod)
     {
         var info = Drag.Info;
         var dest = info.Destination;
-        if (dest == null || mod == DropModifier.Clone)
+        if (dest is null || mod == DropModifier.Clone)
             return false;
 
         if (dest.IsEmpty() || mod == DropModifier.Overwrite)

PKHeX.WinForms/Controls/Slots/DragManager.cs

@@ -11,7 +11,7 @@ public sealed class DragManager
 
     public void SetCursor(Form? f, Cursor? z)
     {
-        if (f != null)
+        if (f is not null)
             f.Cursor = z;
         Info.Cursor = z;
     }

PKHeX.WinForms/Controls/Slots/SlotChangeInfo.cs

@@ -22,7 +22,7 @@ public void Reset()
         Cursor = null;
     }
 
-    public bool SameLocation => (Destination != null) && (Source?.Equals(Destination) ?? false);
+    public bool SameLocation => (Destination is not null) && (Source?.Equals(Destination) ?? false);
 
     private bool SourceIsParty => Source?.Slot is SlotInfoParty;
     private bool DestinationIsParty => Destination?.Slot is SlotInfoParty;

PKHeX.WinForms/Controls/Slots/SlotHoverHandler.cs

@@ -26,7 +26,7 @@ public sealed class SlotHoverHandler : IDisposable
     public void Start(PictureBox pb, SlotTrackerImage lastSlot)
     {
         var view = WinFormsUtil.FindFirstControlOfType<ISlotViewer<PictureBox>>(pb);
-        if (view == null)
+        if (view is null)
             throw new InvalidCastException(nameof(view));
         var data = view.GetSlotData(pb);
         var pk = data.Read(view.SAV);
@@ -52,7 +52,7 @@ public void Start(PictureBox pb, SlotTrackerImage lastSlot)
             bg = Hover;
         }
 
-        if (orig != null)
+        if (orig is not null)
             bg = ImageUtil.LayerImage(orig, bg, 0, 0);
         pb.BackgroundImage = LastSlot.CurrentBackground = bg;
 
@@ -61,7 +61,7 @@ public void Start(PictureBox pb, SlotTrackerImage lastSlot)
 
     public void Stop()
     {
-        if (Slot != null)
+        if (Slot is not null)
         {
             if (HoverWorker.Enabled)
                 HoverWorker.Stop();

PKHeX.WinForms/Controls/Slots/SlotList.cs

@@ -88,7 +88,7 @@ public ISlotInfo GetSlotData(PictureBox view)
     public int GetSlot(PictureBox sender)
     {
         var view = WinFormsUtil.GetUnderlyingControl<PictureBox>(sender);
-        if (view == null)
+        if (view is null)
             return -1;
         return slots.IndexOf(view);
     }

PKHeX.WinForms/MainWindow/Main.cs

@@ -608,7 +608,7 @@ private void OpenFromPath(string path)
     private void OpenFile(byte[] input, string path, string ext)
     {
         var obj = FileUtil.GetSupportedFile(input, ext, C_SAV.SAV);
-        if (obj != null && LoadFile(obj, path))
+        if (obj is not null && LoadFile(obj, path))
             return;
 
         WinFormsUtil.Error(GetHintInvalidFile(input, path),
@@ -635,7 +635,7 @@ private static string GetHintInvalidFile(ReadOnlySpan<byte> input, string path)
 
     private bool LoadFile(object? input, string path)
     {
-        if (input == null)
+        if (input is null)
             return false;
 
         switch (input)
@@ -664,7 +664,7 @@ private bool OpenPKM(PKM pk)
         var destType = C_SAV.SAV.PKMType;
         var tmp = EntityConverter.ConvertToType(pk, destType, out var c);
         Debug.WriteLine(c.GetDisplayString(pk, destType));
-        if (tmp == null)
+        if (tmp is null)
             return false;
         C_SAV.SAV.AdaptPKM(tmp);
         PKME_Tabs.PopulateFields(tmp);
@@ -692,7 +692,7 @@ private bool OpenMysteryGift(MysteryGift tg, string path)
         var destType = C_SAV.SAV.PKMType;
         var pk = EntityConverter.ConvertToType(temp, destType, out var c);
 
-        if (pk == null)
+        if (pk is null)
         {
             WinFormsUtil.Alert(c.GetDisplayString(temp, destType));
             return true;
@@ -1175,7 +1175,7 @@ private void GetPreview(PictureBox pb, PKM? pk = null)
         pk ??= PreparePKM(false); // don't perform control loss click
 
         var menu = dragout.ContextMenuStrip;
-        if (menu != null)
+        if (menu is not null)
             menu.Enabled = pk.Species != 0 || HaX; // Species
 
         pb.Image = pk.Sprite(C_SAV.SAV);
@@ -1211,7 +1211,7 @@ private static void Main_DragEnter(object? sender, DragEventArgs? e)
             return;
         if (e.AllowedEffect == (DragDropEffects.Copy | DragDropEffects.Link)) // external file
             e.Effect = DragDropEffects.Copy;
-        else if (e.Data != null) // within
+        else if (e.Data is not null) // within
             e.Effect = DragDropEffects.Copy;
     }
 

PKHeX.WinForms/MainWindow/PluginLoader.cs

@@ -32,7 +32,7 @@ public static class PluginLoader
                 Debug.WriteLine(ex.Message);
                 continue;
             }
-            if (activate != null)
+            if (activate is not null)
                 yield return activate;
         }
     }

PKHeX.WinForms/Misc/QR.cs

@@ -49,7 +49,7 @@ public QR(Image qr, Image icon, PKM pk, params string[] lines)
     private void ResizeWindow()
     {
         var img = PB_QR.Image;
-        if (img == null)
+        if (img is null)
             return;
         splitContainer1.Height = splitContainer1.Panel1.Height + img.Height;
         splitContainer1.Width = img.Width;

PKHeX.WinForms/Program.cs

@@ -116,7 +116,7 @@ private static void CurrentDomain_UnhandledException(object sender, UnhandledExc
             {
                 Error("You have installed PKHeX incorrectly. Please ensure you have unzipped all files before running.");
             }
-            else if (ex != null)
+            else if (ex is not null)
             {
                 var msg = GetErrorMessage(ex);
                 ErrorWindow.ShowErrorDialog($"{msg}\nPKHeX must now close.", ex, false);

PKHeX.WinForms/Subforms/KChart.Designer.cs

@@ -13,7 +13,7 @@ partial class KChart
         /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
         protected override void Dispose(bool disposing)
         {
-            if (disposing && (components != null))
+            if (disposing && (components is not null))
             {
                 components.Dispose();
             }

PKHeX.WinForms/Subforms/Misc/PropertyComparer.cs

@@ -18,7 +18,7 @@ public PropertyComparer(PropertyDescriptor property, ListSortDirection direction
         propertyDescriptor = property;
         Type comparerForPropertyType = typeof(Comparer<>).MakeGenericType(property.PropertyType);
         var ci = comparerForPropertyType.InvokeMember("Default", BindingFlags.Static | BindingFlags.GetProperty | BindingFlags.Public, null, null, null);
-        comparer = ci == null ? new Comparer(CultureInfo.InvariantCulture) : (IComparer) ci;
+        comparer = ci is null ? new Comparer(CultureInfo.InvariantCulture) : (IComparer) ci;
         SetListSortDirection(direction);
     }
 

PKHeX.WinForms/Subforms/PKM Editors/BatchEditor.cs

@@ -153,7 +153,7 @@ private void RunBatchEdit(StringInstructionSet[] sets, string source, string? de
                 RunBatchEditSaveFile(sets, boxes: true);
             else if (RB_Party.Checked)
                 RunBatchEditSaveFile(sets, party: true);
-            else if (destination != null)
+            else if (destination is not null)
                 RunBatchEditFolder(sets, source, destination);
             finished = true;
         };
@@ -269,7 +269,7 @@ private void TryProcess(string source, string destDir, IReadOnlyList<StringInstr
 
         byte[] data = File.ReadAllBytes(source);
         _ = FileUtil.TryGetPKM(data, out var pk, fi.Extension, SAV);
-        if (pk == null)
+        if (pk is null)
             return;
 
         var info = new SlotInfoFile(source);

PKHeX.WinForms/Subforms/PKM Editors/TechRecordEditor.cs

@@ -135,7 +135,7 @@ private void PressKeyCell(object sender, KeyEventArgs e)
             return;
 
         var row = dgv.CurrentRow;
-        if (row == null)
+        if (row is null)
             return;
 
         // Toggle the checkbox of cell 0

PKHeX.WinForms/Subforms/PKM Editors/Text.Designer.cs

@@ -13,7 +13,7 @@ partial class TrashEditor
         /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
         protected override void Dispose(bool disposing)
         {
-            if (disposing && (components != null))
+            if (disposing && (components is not null))
             {
                 components.Dispose();
             }

PKHeX.WinForms/Subforms/ReportGrid.cs

@@ -108,7 +108,7 @@ private void HideSpecifiedColumns(ReadOnlySpan<string> hide)
             if (prop.Length == 0)
                 continue;
             var col = dgData.Columns[prop];
-            if (col != null)
+            if (col is not null)
                 col.Visible = false;
         }
     }
@@ -194,7 +194,7 @@ protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
             return base.ProcessCmdKey(ref msg, keyData);
 
         var content = dgData.GetClipboardContent();
-        if (content == null)
+        if (content is null)
             return base.ProcessCmdKey(ref msg, keyData);
 
         string data = content.GetText();

PKHeX.WinForms/Subforms/SAV_Database.cs

@@ -116,7 +116,7 @@ public SAV_Database(PKMEditor f1, SAVEditor saveditor)
             if (!z.IsFaulted)
                 return;
             Invoke((MethodInvoker)(() => L_Count.Text = "Failed."));
-            if (z.Exception == null)
+            if (z.Exception is null)
                 return;
             WinFormsUtil.Error("Loading database failed.", z.Exception.InnerException ?? new Exception(z.Exception.Message));
         });
@@ -410,7 +410,7 @@ private static List<SlotCache> LoadPKMSaves(string pkmdb, SaveFile sav, List<Sea
         if (Main.Settings.EntityDb.FilterUnavailableSpecies)
         {
             var filter = GetFilterForSaveFile(sav);
-            if (filter != null)
+            if (filter is not null)
                 result.RemoveAll(z => !filter(z.Entity));
         }
 
@@ -436,7 +436,7 @@ private static List<SlotCache> LoadPKMSaves(string pkmdb, SaveFile sav, List<Sea
     private static void TryAddPKMsFromSaveFilePath(ConcurrentBag<SlotCache> dbTemp, string file)
     {
         var sav = SaveUtil.GetVariantSAV(file);
-        if (sav == null)
+        if (sav is null)
         {
             if (FileUtil.TryGetMemoryCard(file, out var mc))
                 TryAddPKMsFromMemoryCard(dbTemp, mc, file);

PKHeX.WinForms/Subforms/SAV_Encounters.cs

@@ -256,9 +256,9 @@ private IEnumerable<IEncounterInfo> SearchDatabase(CancellationToken token)
         var versions = settings.GetVersions(SAV);
         var species = settings.Species == 0 ? GetFullRange(SAV.MaxSpeciesID) : [settings.Species];
         var results = GetAllSpeciesFormEncounters(species, SAV.Personal, versions, moves, pk, token);
-        if (settings.SearchEgg != null)
+        if (settings.SearchEgg is not null)
             results = results.Where(z => z.IsEgg == settings.SearchEgg);
-        if (settings.SearchShiny != null)
+        if (settings.SearchShiny is not null)
             results = results.Where(z => z.IsShiny == settings.SearchShiny);
 
         // return filtered results
@@ -333,9 +333,9 @@ private sealed class ReferenceComparer<T> : IEqualityComparer<T> where T : class
     {
         public bool Equals(T? x, T? y)
         {
-            if (x == null)
+            if (x is null)
                 return false;
-            if (y == null)
+            if (y is null)
                 return false;
             return RuntimeHelpers.GetHashCode(x).Equals(RuntimeHelpers.GetHashCode(y));
         }

PKHeX.WinForms/Subforms/SAV_FolderList.cs

@@ -128,11 +128,11 @@ private static IEnumerable<CustomFolderPath> GetUserPaths()
     private static IEnumerable<CustomFolderPath> GetConsolePaths(IEnumerable<string> drives)
     {
         var path3DS = SaveFinder.Get3DSLocation(drives);
-        if (path3DS == null)
+        if (path3DS is null)
             return [];
 
         var root = Path.GetPathRoot(path3DS);
-        if (root == null)
+        if (root is null)
             return [];
 
         var paths = SaveFinder.Get3DSBackupPaths(root);
@@ -142,11 +142,11 @@ private static IEnumerable<CustomFolderPath> GetConsolePaths(IEnumerable<string>
     private static IEnumerable<CustomFolderPath> GetSwitchPaths(IEnumerable<string> drives)
     {
         var pathNX = SaveFinder.GetSwitchLocation(drives);
-        if (pathNX == null)
+        if (pathNX is null)
             return [];
 
         var root = Path.GetPathRoot(pathNX);
-        if (root == null)
+        if (root is null)
             return [];
 
         var paths = SaveFinder.GetSwitchBackupPaths(root);
@@ -204,7 +204,7 @@ private ContextMenuStrip GetContextMenu(DataGridView dgv)
     private void ClickOpenFile(DataGridView dgv)
     {
         var sav = GetSaveFile(dgv);
-        if (sav == null || !File.Exists(sav.FilePath))
+        if (sav is null || !File.Exists(sav.FilePath))
         {
             WinFormsUtil.Alert(MsgFileLoadFail);
             return;
@@ -216,7 +216,7 @@ private void ClickOpenFile(DataGridView dgv)
     private void ClickOpenFolder(DataGridView dgv)
     {
         var sav = GetSaveFile(dgv);
-        if (sav == null || !File.Exists(sav.FilePath))
+        if (sav is null || !File.Exists(sav.FilePath))
         {
             WinFormsUtil.Alert(MsgFileLoadFail);
             return;
@@ -388,7 +388,7 @@ private static void ToggleRowVisibility(DataGridView dg, int column, ReadOnlySpa
         }
         var cell = row.Cells[column];
         var value = cell.Value?.ToString();
-        if (value == null)
+        if (value is null)
         {
             row.Visible = false;
             return;

PKHeX.WinForms/Subforms/SAV_MysteryGiftDB.cs

@@ -134,7 +134,7 @@ private void ClickView(object sender, EventArgs e)
             return;
         var temp = Results[index].ConvertToPKM(SAV);
         var pk = EntityConverter.ConvertToType(temp, SAV.PKMType, out var c);
-        if (pk == null)
+        if (pk is null)
         {
             WinFormsUtil.Error(c.GetDisplayString(temp, SAV.PKMType));
             return;

PKHeX.WinForms/Subforms/Save Editors/Gen3/SAV_Misc3.cs

@@ -275,7 +275,7 @@ private void ChangeStat1(object sender, EventArgs e)
             rb.Checked = false;
 
         var bft = BFT[BFF[facility][1]];
-        if (bft == null)
+        if (bft is null)
         {
             CB_Stats2.Visible = false;
         }
@@ -308,7 +308,7 @@ private void StatAddrControl(int SetValToSav = -2, bool SetSavToVal = false)
 
         int BattleType = CB_Stats2.SelectedIndex;
         var bft = BFT[BFF[Facility][1]];
-        if (bft == null)
+        if (bft is null)
             BattleType = 0;
         else if (BattleType < 0)
             return;
@@ -455,7 +455,7 @@ private void SaveBattleFrontier()
     private void BTN_Symbol_Click(object sender, EventArgs e)
     {
         var match = Array.Find(SymbolButtonA, z => z == sender);
-        if (match == null)
+        if (match is null)
             return;
 
         var color = match.BackColor;
@@ -475,7 +475,7 @@ private void LoadRecords()
 
         CB_Record.SelectedIndexChanged += (_, _) =>
         {
-            if (CB_Record.SelectedValue == null)
+            if (CB_Record.SelectedValue is null)
                 return;
 
             var index = WinFormsUtil.GetIndex(CB_Record);
@@ -487,7 +487,7 @@ private void LoadRecords()
         LoadRecordID(0);
         NUD_RecordValue.ValueChanged += (_, _) =>
         {
-            if (CB_Record.SelectedValue == null)
+            if (CB_Record.SelectedValue is null)
                 return;
 
             var index = WinFormsUtil.GetIndex(CB_Record);

PKHeX.WinForms/Subforms/Save Editors/Gen4/SAV_HoneyTree.cs

@@ -86,7 +86,7 @@ private void ReadTree()
 
     private void SaveTree()
     {
-        if (Tree == null)
+        if (Tree is null)
             return;
 
         Tree.Time = (uint)NUD_Time.Value;

PKHeX.WinForms/Subforms/Save Editors/Gen4/SAV_Pokedex4.cs

@@ -280,7 +280,7 @@ private void ToggleSeen(object sender, EventArgs e)
         if (editing)
             return;
         var lb = sender == B_GLeft ? LB_NGender : LB_Gender;
-        if (lb == null || lb.SelectedIndex < 0)
+        if (lb is null || lb.SelectedIndex < 0)
         {
             WinFormsUtil.Alert("No Gender selected.");
             return;
@@ -299,7 +299,7 @@ private void MoveGender(object sender, EventArgs e)
         if (editing)
             return;
         var lb = LB_Gender;
-        if (lb == null || lb.SelectedIndex < 0)
+        if (lb is null || lb.SelectedIndex < 0)
         {
             WinFormsUtil.Alert("No Gender selected.");
             return;
@@ -329,7 +329,7 @@ private void ToggleForm(object sender, EventArgs e)
         if (editing)
             return;
         var lb = sender == B_FLeft ? LB_NForm : LB_Form;
-        if (lb == null || lb.SelectedIndex < 0)
+        if (lb is null || lb.SelectedIndex < 0)
         {
             WinFormsUtil.Alert("No Form selected.");
             return;
@@ -348,7 +348,7 @@ private void MoveForm(object sender, EventArgs e)
         if (editing)
             return;
         var lb = LB_Form;
-        if (lb == null || lb.SelectedIndex < 0)
+        if (lb is null || lb.SelectedIndex < 0)
         {
             WinFormsUtil.Alert("No Form selected.");
             return;

PKHeX.WinForms/Subforms/Save Editors/Gen5/SAV_Misc5.cs

@@ -567,7 +567,7 @@ public static string GetSpeciesName(ushort species)
 
     private void UpdateSlotValue(object sender, EventArgs e)
     {
-        if (CurrentSlot == null)
+        if (CurrentSlot is null)
             return;
 
         if (sender == CB_Species)

PKHeX.WinForms/Subforms/Save Editors/Gen6/SAV_BoxLayout.cs

@@ -202,7 +202,7 @@ private void ChangeBoxBackground(object sender, EventArgs e)
     private bool MoveItem(int direction)
     {
         // Checking selected item
-        if (LB_BoxSelect.SelectedItem == null || LB_BoxSelect.SelectedIndex < 0)
+        if (LB_BoxSelect.SelectedItem is null || LB_BoxSelect.SelectedIndex < 0)
             return false; // No selected item - nothing to do
 
         // Calculate new index using move direction

PKHeX.WinForms/Subforms/Save Editors/Gen6/SAV_SecretBase.cs

@@ -270,7 +270,7 @@ private void ChangeIndexBase(object sender, EventArgs e)
             return;
 
         var bdata = CurrentBase;
-        if (bdata != null)
+        if (bdata is not null)
             SaveCurrent(bdata);
 
         ResetLoadNew();
@@ -466,7 +466,7 @@ private void B_Save_Click(object sender, EventArgs e)
         SAV.Records.SetRecord(080, (int)flags);
 
         var bdata = CurrentBase;
-        if (bdata != null)
+        if (bdata is not null)
             SaveCurrent(bdata);
 
         Origin.CopyChangesFrom(SAV);

PKHeX.WinForms/Subforms/Save Editors/Gen7/SAV_Trainer7.cs

@@ -119,7 +119,7 @@ private void GetTextBoxes()
             CB_AlolaTime.SelectedValue = (int)timeA;
 
         // ReSharper disable once ConditionIsAlwaysTrueOrFalse
-        if (CB_AlolaTime.SelectedValue == null)
+        if (CB_AlolaTime.SelectedValue is null)
             CB_AlolaTime.Enabled = false;
 
         NUD_M.Value = SAV.Situation.M;

PKHeX.WinForms/Subforms/Save Editors/Gen7/SAV_Trainer7GG.cs

@@ -41,7 +41,7 @@ private void Main_DragEnter(object? sender, DragEventArgs? e)
             return;
         if (e.AllowedEffect == (DragDropEffects.Copy | DragDropEffects.Link)) // external file
             e.Effect = DragDropEffects.Copy;
-        else if (e.Data != null) // within
+        else if (e.Data is not null) // within
             e.Effect = DragDropEffects.Move;
     }