Misc edge case tests

Gen9a Antishiny edge case
Evolve-move traversal tweaks; eager checks and more

PKHeX.Core/Legality/Encounters/Templates/Gen9a/LumioseRNG.cs

@@ -321,13 +321,15 @@ private static uint GetAdaptedPID(ref Xoroshiro128Plus rand, PKM pk, in Generate
         else // Never
         {
             if (ShinyUtil.GetIsShiny6(fakeTID, pid)) // battled
-                pid ^= 0x1000_0000;
+                pid = AntiShiny(pid);
             if (ShinyUtil.GetIsShiny6(pk.ID32, pid)) // captured
-                pid ^= 0x1000_0000;
+                pid = AntiShiny(pid);
         }
         return pid;
     }
 
+    public static uint AntiShiny(uint pid) => pid ^ 0x1000_0000;
+
     private static bool IsMatchUnknownPreFillIVs(PKM pk, in GenerateParam9a enc, Xoroshiro128Plus rand)
     {
         int k = enc.FlawlessIVs;

PKHeX.Core/Legality/Encounters/Templates/Gen9a/LumioseSolver.cs

@@ -81,6 +81,12 @@ private static bool TryGetSeedConsecutive(in GenerateParam9a param, PKM pk, uint
     private static bool TryGetSeedSkip(in GenerateParam9a param, PKM pk, uint ec, uint pid, out ulong seed)
     {
         var solver = new XoroMachineSkip(ec, pid);
+        if (TryGetSeed(param, pk, solver, out seed))
+            return true;
+
+        // Try again assuming the FakeTrainer XORed the resulting PID to be anti-shiny (terrible luck for the player).
+        pid = LumioseRNG.AntiShiny(pid);
+        solver = new XoroMachineSkip(ec, pid);
         return TryGetSeed(param, pk, solver, out seed);
     }
 

PKHeX.Core/Legality/LearnSource/Group/LearnGroup7.cs

@@ -13,10 +13,10 @@ public sealed class LearnGroup7 : ILearnGroup
 
     public ILearnGroup? GetPrevious(PKM pk, EvolutionHistory history, IEncounterTemplate enc, LearnOption option) => enc.Generation switch
     {
-        Generation => null,
+        1 => LearnGroup1.Instance,
-        1 => history.HasVisitedGen1 ? LearnGroup1.Instance : null,
+        2 => LearnGroup2.Instance,
-     <= 2 => history.HasVisitedGen2 ? LearnGroup2.Instance : null,
+        (3 or 4 or 5 or 6) => LearnGroup6.Instance,
-        _ => history.HasVisitedGen6 ? LearnGroup6.Instance : null,
+        _ => null,
     };
 
     public bool HasVisited(PKM pk, EvolutionHistory history) => history.HasVisitedGen7;

PKHeX.Core/Legality/LearnSource/Group/LearnGroup8.cs

@@ -54,7 +54,7 @@ public sealed class LearnGroup8 : ILearnGroup
 
         var home = LearnGroupHOME.Instance;
         if (option != LearnOption.HOME && home.HasVisited(pk, history))
-            return home.Check(result, current, pk, history, enc, types);
+            return home.Check(result, current, pk, history, enc, types, option);
         return false;
     }
 

PKHeX.Core/Legality/LearnSource/Group/LearnGroup8a.cs

@@ -27,7 +27,7 @@ public sealed class LearnGroup8a : ILearnGroup
 
         var home = LearnGroupHOME.Instance;
         if (option != LearnOption.HOME && home.HasVisited(pk, history))
-            return home.Check(result, current, pk, history, enc, types);
+            return home.Check(result, current, pk, history, enc, types, option);
         return false;
     }
 

PKHeX.Core/Legality/LearnSource/Group/LearnGroup8b.cs

@@ -33,7 +33,7 @@ public sealed class LearnGroup8b : ILearnGroup
 
         var home = LearnGroupHOME.Instance;
         if (option != LearnOption.HOME && home.HasVisited(pk, history))
-            return home.Check(result, current, pk, history, enc, types);
+            return home.Check(result, current, pk, history, enc, types, option);
         return false;
     }
 

PKHeX.Core/Legality/LearnSource/Group/LearnGroup9.cs

@@ -35,7 +35,7 @@ public sealed class LearnGroup9 : ILearnGroup
 
         var home = LearnGroupHOME.Instance;
         if (option != LearnOption.HOME && home.HasVisited(pk, history))
-            return home.Check(result, current, pk, history, enc, types);
+            return home.Check(result, current, pk, history, enc, types, option);
         return false;
     }
 

PKHeX.Core/Legality/LearnSource/Group/LearnGroup9a.cs

@@ -30,7 +30,7 @@ public sealed class LearnGroup9a : ILearnGroup
 
         var home = LearnGroupHOME.Instance;
         if (option != LearnOption.HOME && home.HasVisited(pk, history))
-            return home.Check(result, current, pk, history, enc, types);
+            return home.Check(result, current, pk, history, enc, types, option);
         return false;
     }
 

PKHeX.Core/Legality/LearnSource/Group/LearnGroupHOME.cs

@@ -12,13 +12,14 @@ namespace PKHeX.Core;
 public sealed class LearnGroupHOME : ILearnGroup
 {
     public static readonly LearnGroupHOME Instance = new();
+    private const LearnOption Option = LearnOption.HOME;
     public ushort MaxMoveID => 0;
 
     public ILearnGroup? GetPrevious(PKM pk, EvolutionHistory history, IEncounterTemplate enc, LearnOption option) => null;
     public bool HasVisited(PKM pk, EvolutionHistory history) => pk is IHomeTrack { HasTracker: true } || !ParseSettings.IgnoreTransferIfNoTracker;
 
     public bool Check(Span<MoveResult> result, ReadOnlySpan<ushort> current, PKM pk, EvolutionHistory history,
-        IEncounterTemplate enc, MoveSourceType types = MoveSourceType.All, LearnOption option = LearnOption.HOME)
+        IEncounterTemplate enc, MoveSourceType types = MoveSourceType.All, LearnOption option = Option)
     {
         var context = pk.Context;
         if (context == EntityContext.None)
@@ -29,36 +30,36 @@ public sealed class LearnGroupHOME : ILearnGroup
         if (history.HasVisitedGen9 && pk is not PK9)
         {
             var instance = LearnGroup9.Instance;
-            instance.Check(result, current, pk, history, enc, types, option);
+            instance.Check(result, current, pk, history, enc, types, Option);
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
         if (history.HasVisitedZA && pk is not PA9)
         {
             var instance = LearnGroup9a.Instance;
-            instance.Check(result, current, pk, history, enc, types, option);
+            instance.Check(result, current, pk, history, enc, types, Option);
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
         if (history.HasVisitedSWSH && pk is not PK8)
         {
             var instance = LearnGroup8.Instance;
-            instance.Check(result, current, pk, history, enc, types, option);
+            instance.Check(result, current, pk, history, enc, types, Option);
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
         if (history.HasVisitedPLA && pk is not PA8)
         {
             var instance = LearnGroup8a.Instance;
-            instance.Check(result, current, pk, history, enc, types, option);
+            instance.Check(result, current, pk, history, enc, types, Option);
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
         if (history.HasVisitedBDSP && pk is not PB8)
         {
             var instance = LearnGroup8b.Instance;
-            instance.Check(result, current, pk, history, enc, types, option);
+            instance.Check(result, current, pk, history, enc, types, Option);
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
 
@@ -67,14 +68,14 @@ public sealed class LearnGroupHOME : ILearnGroup
         // SW/SH is the only game that can ever harbor external moves, and is the only game that uses Battle Version.
         if (TryAddOriginalMoves(result, current, pk, enc))
         {
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
 
         // HOME is silly and allows form exclusive moves to be transferred without ever knowing the move.
         if (TryAddExclusiveMoves(result, current, pk))
         {
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
 
@@ -82,8 +83,8 @@ public sealed class LearnGroupHOME : ILearnGroup
         {
             // PK8 w/ Battle Version can be ignored, as LGP/E has separate HOME data.
             var instance = LearnGroup7b.Instance;
-            instance.Check(result, current, pk, history, enc, types, option);
+            instance.Check(result, current, pk, history, enc, types, Option);
-            if (CleanPurge(result, current, pk, types, local, evos))
+            if (CleanPurge(result, current, pk, types, local, evos, option))
                 return true;
         }
         else if (history.HasVisitedGen7)
@@ -93,8 +94,8 @@ public sealed class LearnGroupHOME : ILearnGroup
             ILearnGroup instance = LearnGroup7.Instance;
             while (true)
             {
-                instance.Check(result, current, pk, history, enc, types, option);
+                instance.Check(result, current, pk, history, enc, types, Option);
-                if (CleanPurge(result, current, pk, types, local, evos))
+                if (CleanPurge(result, current, pk, types, local, evos, option))
                     return true;
                 var prev = instance.GetPrevious(pk, history, enc, option);
                 if (prev is null)
@@ -111,8 +112,11 @@ public sealed class LearnGroupHOME : ILearnGroup
     /// Scan the results and remove any that are not valid for the game <see cref="local"/> game.
     /// </summary>
     /// <returns>True if all results are valid.</returns>
-    private static bool CleanPurge(Span<MoveResult> result, ReadOnlySpan<ushort> current, PKM pk, MoveSourceType types, IHomeSource local, ReadOnlySpan<EvoCriteria> evos)
+    private static bool CleanPurge(Span<MoveResult> result, ReadOnlySpan<ushort> current, PKM pk, MoveSourceType types, IHomeSource local, ReadOnlySpan<EvoCriteria> evos, LearnOption option)
     {
+        if (option == LearnOption.AtAnyTime)
+            return MoveResult.AllParsed(result);
+
         // The logic used to update the results did not check if the move could be learned in the local game.
         // Double-check the results and remove any that are not valid for the local game.
         // SW/SH will continue to iterate downwards to previous groups after HOME is checked, so we can exactly check via Environment.

PKHeX.Core/Legality/Restrictions/EvolutionRestrictions.cs

@@ -15,6 +15,9 @@ internal static class EvolutionRestrictions
     /// <summary>
     /// List of species that evolve from a previous species having a move while leveling up
     /// </summary>
+    /// <remarks>
+    /// Using moves with a counter stored in form argument is explicitly checked via other logic. <see cref="IsFormArgEvolution"/>
+    /// </remarks>
     private static ushort GetSpeciesEvolutionMove(ushort species) => species switch
     {
         (int)Sylveon => EEVEE,
@@ -28,15 +31,22 @@ internal static class EvolutionRestrictions
         (int)Tsareena => (int)Stomp,
         (int)Naganadel => (int)DragonPulse,
         (int)Grapploct => (int)Taunt,
+
+        // Form Argument evolutions sometimes with extra conditions; verify here because they aren't checked "completely" elsewhere (yet).
         (int)Wyrdeer => (int)PsyshieldBash,
         (int)Overqwil => (int)BarbBarrage,
         (int)Annihilape => (int)RageFist,
+
         (int)Farigiraf => (int)TwinBeam,
         (int)Dudunsparce => (int)HyperDrill,
         (int)Hydrapple => (int)DragonCheer,
         _ => NONE,
     };
 
+    /// <summary>
+    /// Checks if the evolution is the "rare" variant (less common).
+    /// </summary>
+    /// <param name="encryptionConstant">Random value used to pivot between evolution results.</param>  
     public static bool IsEvolvedSpeciesFormRare(uint encryptionConstant) => encryptionConstant % 100 is 0;
 
     /// <summary>
@@ -50,6 +60,9 @@ internal static class EvolutionRestrictions
         _ => throw new ArgumentOutOfRangeException(nameof(species), species, "Incorrect EC%100 species."),
     };
 
+    /// <summary>
+    /// Checks if the evolution result matches what is expected for <see cref="IsEvolvedSpeciesFormRare"/>
+    /// </summary>
     public static bool GetIsExpectedEvolveFormEC100(ushort species, byte form, bool rare) => species switch
     {
         (ushort)Maushold => form == (byte)(rare ? 0 : 1),
@@ -76,6 +89,9 @@ public static bool IsFormArgEvolution(ushort species)
     /// Checks if the <see cref="pk"/> is correctly evolved, assuming it had a known move requirement evolution in its evolution chain.
     /// </summary>
     /// <returns>True if unnecessary to check or the evolution was valid.</returns>
+    /// <remarks>
+    /// Performs some eager checks to skip doing a full evolution tree move check.
+    /// </remarks>
     public static bool IsValidEvolutionWithMove(PKM pk, LegalInfo info)
     {
         // Known-move evolutions were introduced in Gen4.
@@ -88,6 +104,15 @@ public static bool IsValidEvolutionWithMove(PKM pk, LegalInfo info)
         if (enc.Species == species)
             return true;
 
+        // All move evolutions arrive at a maximally-evolved species chain.
+        // Except for Mr. Rime -- just manually devolve and let the rest of the logic check.
+        if (species is (ushort)MrRime)
+        {
+            species = (ushort)MrMime;
+            if (enc.Species == species)
+                return true;
+        }
+
         // Exclude evolution paths that did not require a move w/level-up evolution
         var move = GetSpeciesEvolutionMove(species);
         if (move is NONE)
@@ -95,6 +120,10 @@ public static bool IsValidEvolutionWithMove(PKM pk, LegalInfo info)
         if (!IsMoveSlotAvailable(info.Moves))
             return false;
 
+        // Check if the move is in relearn moves (can know at any time)
+        if (pk.Format >= 6 && IsMoveInRelearnSource(pk, info, move))
+            return true;
+
         // Check the entire chain to see if it could have learnt it at any point.
         var head = LearnGroupUtil.GetCurrentGroup(pk);
         var pruned = info.EvoChainsAllGens.PruneKeepPreEvolutions(species);
@@ -104,6 +133,54 @@ public static bool IsValidEvolutionWithMove(PKM pk, LegalInfo info)
         return MemoryPermissions.GetCanKnowMove(enc, move, pruned, pk, head);
     }
 
+    private static bool IsMoveInRelearnSource(PKM pk, LegalInfo info, ushort move)
+    {
+        if (move is not EEVEE)
+            return IsMoveInRelearn(pk, info, move);
+        return IsMoveInRelearn(pk, info, EeveeFairyMoves);
+    }
+
+    private static bool IsMoveInRelearn(PKM pk, LegalInfo info, ReadOnlySpan<ushort> arr)
+    {
+        foreach (var move in arr)
+        {
+            if (IsMoveInRelearn(pk, info, move))
+                return true;
+        }
+        return false;
+    }
+
+    private static bool IsMoveInRelearn(PKM pk, LegalInfo info, ushort move)
+    {
+        if (pk.IsOriginalMovesetDeleted())
+            return WasMoveInRelearn(pk, info, move);
+
+        var first = pk.RelearnMove1;
+        if (first is 0) // eager check
+            return false;
+        if (pk.RelearnMove1 == move)
+            return true;
+        if (pk.RelearnMove2 == move)
+            return true;
+        if (pk.RelearnMove3 == move)
+            return true;
+        if (pk.RelearnMove4 == move)
+            return true;
+        return false;
+    }
+
+    private static bool WasMoveInRelearn(PKM pk, LegalInfo info, ushort move)
+    {
+        for (var i = 0; i < info.Moves.Length; i++)
+        {
+            if (pk.GetMove(i) != move)
+                continue;
+            var method = info.Moves[i].Info.Method;
+            return method is { IsEggSource: true } or { IsRelearn: true } or LearnMethod.Encounter;
+        }
+        return false;
+    }
+
     private static bool IsValidEvolutionWithMoveAny(IEncounterTemplate enc, ReadOnlySpan<ushort> any, EvolutionHistory history, PKM pk, ILearnGroup head)
     {
         foreach (var move in any)