Mold Breaker shouldn't remove abilities that don't affect direct damage

calc/src/mechanics/gen4.ts

@@ -66,6 +66,8 @@ export function calculateDPP(
     return result;
   }
 
+  const tempAbility = defender.ability;
+
   if (attacker.hasAbility('Mold Breaker')) {
     defender.ability = '' as AbilityName;
     desc.attackerAbility = attacker.ability;
@@ -196,6 +198,14 @@ export function calculateDPP(
   const attack = calculateAttackDPP(gen, attacker, defender, move, field, desc, isCritical);
 
   // #endregion
+
+  // Restores the defender's ability after disabling it for Mold Breaker purposes.
+  // This will make abilities like Rain Dish and Dry Skin work
+  // even when the attacker has Mold Breaker.
+  if (attacker.hasAbility('Mold Breaker')) {
+    defender.ability = tempAbility;
+  }
+
   // #region (Special) Defense
   const defense = calculateDefenseDPP(gen, attacker, defender, move, field, desc, isCritical);
 

calc/src/mechanics/gen56.ts

@@ -95,6 +95,8 @@ export function calculateBWXY(
     return result;
   }
 
+  const tempAbility = defender.ability;
+
   if (attacker.hasAbility('Mold Breaker', 'Teravolt', 'Turboblaze')) {
     defender.ability = '' as AbilityName;
     desc.attackerAbility = attacker.ability;
@@ -285,6 +287,14 @@ export function calculateBWXY(
   const attackStat = move.category === 'Special' ? 'spa' : 'atk';
 
   // #endregion
+
+  // Restores the defender's ability after disabling it for Mold Breaker purposes.
+  // This will make abilities like Rain Dish and Dry Skin work
+  // even when the attacker has Mold Breaker.
+  if (attacker.hasAbility('Mold Breaker', 'Teravolt', 'Turboblaze')) {
+    defender.ability = tempAbility;
+  }
+
   // #region (Special) Defense
 
   const defense = calculateDefenseBWXY(gen, attacker, defender, move, field, desc, isCritical);

calc/src/mechanics/gen789.ts

@@ -169,8 +169,10 @@ export function calculateSMSSSV(
     'Searing Sunraze Smash',
     'Sunsteel Strike'
   );
-  if (!defenderIgnoresAbility && !defender.hasAbility('Poison Heal') &&
-    (attackerIgnoresAbility || moveIgnoresAbility)) {
+
+  const tempAbility = defender.ability;
+
+  if (!defenderIgnoresAbility && (attackerIgnoresAbility || moveIgnoresAbility)) {
     if (attackerIgnoresAbility) desc.attackerAbility = attacker.ability;
     if (defender.hasItem('Ability Shield')) {
       desc.defenderItem = defender.item;
@@ -555,6 +557,15 @@ export function calculateSMSSSV(
           ? 'spa'
           : 'atk';
   // #endregion
+
+  // Restores the defender's ability after disabling it for the purposes of
+  // Mold Breaker and other moves that ignore abilities.
+  // This will make abilities like Rain Dish and Quark Drive work
+  // even when the attacker has Mold Breaker.
+  if (attackerIgnoresAbility || moveIgnoresAbility) {
+    defender.ability = tempAbility;
+  }
+
   // #region (Special) Defense
 
   const defense = calculateDefenseSMSSSV(gen, attacker, defender, move, field, desc, isCritical);

calc/src/test/calc.test.ts

@@ -722,6 +722,32 @@ describe('calc', () => {
           'Lvl 90 Chansey Seismic Toss vs. Lvl 30 0 HP 0 IVs Mew: 90-90 (90 - 90%) -- guaranteed OHKO after sandstorm damage and burn damage'
         );
       });
+
+      inGens(4, 9, ({gen, calculate, Pokemon, Move, Field}) => {
+        test(`Mold Breaker does not disable abilities that don't affect direct damage (gen ${gen})`, () => {
+          const attacker = Pokemon('Rampardos', {
+            ability: 'Mold Breaker',
+          });
+
+          const defender = Pokemon('Blastoise', {
+            ability: 'Rain Dish',
+          });
+
+          const field = Field({
+            weather: 'Rain',
+          });
+
+          const move = Move('Stone Edge');
+
+          const result = calculate(attacker, defender, move, field);
+
+          expect(result.defender.ability).toBe('Rain Dish');
+
+          expect(result.desc()).toBe(
+            '0 Atk Mold Breaker Rampardos Stone Edge vs. 0 HP / 0 Def Blastoise: 168-198 (56.1 - 66.2%) -- guaranteed 2HKO after Rain Dish recovery'
+          );
+        });
+      });
     });
   });