Adds Generational config for Magic Guard (Fix for Gen4+)

include/config/battle.h

@@ -155,6 +155,7 @@
                                                // In Gen3, Effect Spore has a 10% chance to sleep, poison or paralyze, with an equal chance.
                                                // In Gen4, it's 30%. In Gen5+ it has 11% to sleep, 9% chance to poison and 10% chance to paralyze.
 #define B_PICKUP_WILD               GEN_LATEST // In Gen9+, Pickup allows its user to pickup its own used item at the end of the turn in wild battles.
+#define B_MAGIC_GUARD               GEN_LATEST // In Gen4+, Magic Guard ignores immobilization caused by paralysis
 
 // Item settings
 #define B_HP_BERRIES                GEN_LATEST // In Gen4+, berries which restore HP activate immediately after HP drops to half. In Gen3, the effect occurs at the end of the turn.

src/battle_util.c

@@ -3484,7 +3484,10 @@ u8 AtkCanceller_UnableToUseMove(u32 moveType)
             gBattleStruct->atkCancellerTracker++;
             break;
         case CANCELLER_PARALYSED: // paralysis
-            if (!gBattleStruct->isAtkCancelerForCalledMove && (gBattleMons[gBattlerAttacker].status1 & STATUS1_PARALYSIS) && !RandomPercentage(RNG_PARALYSIS, 75))
+            if (!gBattleStruct->isAtkCancelerForCalledMove
+             && gBattleMons[gBattlerAttacker].status1 & STATUS1_PARALYSIS
+             && (GetBattlerAbility(gBattlerAttacker) != ABILITY_MAGIC_GUARD && B_MAGIC_GUARD >= GEN_4)
+             && RandomPercentage(RNG_PARALYSIS, 25))
             {
                 gProtectStructs[gBattlerAttacker].prlzImmobility = TRUE;
                 // This is removed in FRLG and Emerald for some reason

test/battle/ability/magic_guard.c

@@ -15,3 +15,32 @@ SINGLE_BATTLE_TEST("Magic Guard prevents recoil damage to the user")
         NOT HP_BAR(player);
     }
 }
+
+SINGLE_BATTLE_TEST("Magic Guard ignores immobilization that can be caused by paralysis")
+{
+    if (B_MAGIC_GUARD >= GEN_4)
+        PASSES_RANDOMLY(1, 1, RNG_PARALYSIS);
+    else
+        PASSES_RANDOMLY(75, 100, RNG_PARALYSIS);
+    GIVEN {
+        PLAYER(SPECIES_CLEFABLE) { Ability(ABILITY_MAGIC_GUARD); Status1(STATUS1_PARALYSIS);}
+        OPPONENT(SPECIES_WOBBUFFET);
+    } WHEN {
+        TURN { MOVE(player, MOVE_CELEBRATE); }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_CELEBRATE, player);
+    }
+}
+
+SINGLE_BATTLE_TEST("Magic Guard does not ignore speed stat changes caused by paralysis")
+{
+    GIVEN {
+        PLAYER(SPECIES_CLEFABLE) { Speed(100); Ability(ABILITY_MAGIC_GUARD); Status1(STATUS1_PARALYSIS);}
+        OPPONENT(SPECIES_WOBBUFFET) { Speed(99); }
+    } WHEN {
+        TURN { }
+    } SCENE {
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_CELEBRATE, opponent);
+        ANIMATION(ANIM_TYPE_MOVE, MOVE_CELEBRATE, player);
+    }
+}