Check static as-egg locations accurately

Thanks @sora10pls

PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStatic.cs

@@ -251,23 +251,8 @@ namespace PKHeX.Core
             return Form == evo.Form || FormInfo.IsFormChangeable(Species, Form, pkm.Form, pkm.Format);
         }
 
-        protected virtual bool IsMatchEggLocation(PKM pkm)
-        {
-            if (pkm.IsEgg) // unhatched
-            {
-                if (!EggEncounter)
-                    return false;
-                if (EggLocation != pkm.Met_Location)
-                    return pkm.Met_Location == Locations.LinkTrade6 && pkm.Egg_Location == EggLocation;
-                return pkm.Egg_Location == 0;
-            }
-
-            if (EggLocation == pkm.Egg_Location)
-                return true;
-
-            // Only way to mismatch is to be a Link Traded egg.
-            return EggEncounter && pkm.Egg_Location == Locations.LinkTrade6;
-        }
+        // override me if the encounter type has any eggs
+        protected virtual bool IsMatchEggLocation(PKM pkm) => pkm.Egg_Location == 0;
 
         private bool IsMatchGender(PKM pkm)
         {

PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStatic4.cs

@@ -30,42 +30,33 @@ namespace PKHeX.Core
                 return true;
 
             var locs = GetRoamLocations(Species, pk4.EncounterType);
-            return locs.Contains(pkm.Met_Location);
+            return locs.Contains(pk4.Met_Location);
         }
 
         protected override bool IsMatchEggLocation(PKM pkm)
         {
-            if (pkm.Egg_Location == EggLocation)
-            {
-                if (EggLocation == 0)
-                    return true;
+            var eggloc = pkm.Egg_Location;
+            if (!EggEncounter)
+                return eggloc == 0;
 
-                // Check the inverse scenario for 4->5 eggs
-                if (!Locations.IsPtHGSSLocationEgg(EggLocation))
+            // Transferring 4->5 clears Pt/HG/SS location value and keeps Faraway Place
+            if (pkm is not G4PKM pk4)
+            {
+                if (eggloc == Locations.LinkTrade4)
                     return true;
-                return pkm.Format == 4;
+                var cmp = Locations.IsPtHGSSLocationEgg(EggLocation) ? Locations.Faraway4 : EggLocation;
+                return eggloc == cmp;
             }
 
-            if (pkm.IsEgg) // unhatched
-            {
-                if (EggLocation != pkm.Met_Location)
-                    return false;
-                return pkm.Egg_Location == 0;
-            }
+            if (!pk4.IsEgg) // hatched
+                return eggloc == EggLocation || eggloc == Locations.LinkTrade4;
 
-            // Only way to mismatch is to be a Link Traded egg, or traded to Pt/HG/SS and hatched there.
-            if (pkm.Egg_Location == Locations.LinkTrade4)
-                return true;
-
-            // check Pt/HGSS data
-            if (pkm.Format == 4)
+            // Unhatched:
+            if (eggloc != EggLocation)
                 return false;
-
-            if (!Locations.IsPtHGSSLocationEgg(EggLocation)) // non-Pt/HG/SS egg gift
+            if (pk4.Met_Location is not 0 or Locations.LinkTrade4)
                 return false;
-
-            // transferring 4->5 clears Pt/HG/SS location value and keeps Faraway Place
-            return pkm.Egg_Location == Locations.Faraway4;
+            return true;
         }
 
         protected override void ApplyDetails(ITrainerInfo sav, EncounterCriteria criteria, PKM pk)

PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStatic5.cs

@@ -29,20 +29,19 @@ namespace PKHeX.Core
 
         protected override bool IsMatchEggLocation(PKM pkm)
         {
-            if (pkm.IsEgg) // unhatched
-            {
-                if (!EggEncounter)
-                    return false;
-                if (EggLocation != pkm.Met_Location)
-                    return pkm.Met_Location == Locations.LinkTrade5 && pkm.Egg_Location == EggLocation;
-                return pkm.Egg_Location == 0;
-            }
+            var eggloc = pkm.Egg_Location;
+            if (!EggEncounter)
+                return eggloc == EggLocation;
 
-            if (EggLocation == pkm.Egg_Location)
-                return true;
+            if (!pkm.IsEgg) // hatched
+                return eggloc == EggLocation || eggloc == Locations.LinkTrade5;
 
-            // Only way to mismatch is to be a Link Traded egg.
-            return EggEncounter && pkm.Egg_Location == Locations.LinkTrade5;
+            // Unhatched:
+            if (eggloc != EggLocation)
+                return false;
+            if (pkm.Met_Location is not 0 or Locations.LinkTrade5)
+                return false;
+            return true;
         }
 
         private static readonly int[] Roaming_MetLocation_BW =

PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStatic6.cs

@@ -30,6 +30,23 @@
             return loc is 180 or 186 or 194;
         }
 
+        protected override bool IsMatchEggLocation(PKM pkm)
+        {
+            var eggloc = pkm.Egg_Location;
+            if (!EggEncounter)
+                return eggloc == EggLocation;
+
+            if (!pkm.IsEgg) // hatched
+                return eggloc == EggLocation || eggloc == Locations.LinkTrade6;
+
+            // Unhatched:
+            if (eggloc != EggLocation)
+                return false;
+            if (pkm.Met_Location is not 0 or Locations.LinkTrade6)
+                return false;
+            return true;
+        }
+
         protected override void ApplyDetails(ITrainerInfo sav, EncounterCriteria criteria, PKM pk)
         {
             base.ApplyDetails(sav, criteria, pk);

PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStatic7.cs

@@ -23,6 +23,23 @@ namespace PKHeX.Core
             return base.IsMatchLocation(pkm);
         }
 
+        protected override bool IsMatchEggLocation(PKM pkm)
+        {
+            var eggloc = pkm.Egg_Location;
+            if (!EggEncounter)
+                return eggloc == EggLocation;
+
+            if (!pkm.IsEgg) // hatched
+                return eggloc == EggLocation || eggloc == Locations.LinkTrade6;
+
+            // Unhatched:
+            if (eggloc != EggLocation)
+                return false;
+            if (pkm.Met_Location is not 0 or Locations.LinkTrade6)
+                return false;
+            return true;
+        }
+
         protected override bool IsMatchForm(PKM pkm, DexLevel evo)
         {
             if (SkipFormCheck)

PKHeX.Core/Legality/Encounters/EncounterStatic/EncounterStaticShadow.cs

@@ -41,11 +41,6 @@ namespace PKHeX.Core
             113, // Pyrite Town
         };
 
-        protected override bool IsMatchEggLocation(PKM pkm)
-        {
-            return true; // transfer location verified later
-        }
-
         protected override bool IsMatchLocation(PKM pkm)
         {
             if (pkm.Format != 3)