How to use

CanAttackAsThoughItDidntHaveDefenderTargetEffect

in

mage.abilities.effects.common.combat

@Override
public CanAttackAsThoughItDidntHaveDefenderTargetEffect copy() {
  return new CanAttackAsThoughItDidntHaveDefenderTargetEffect(this);
}

@Override
public boolean applies(UUID objectId, Ability source, UUID affectedControllerId, Game game) {
  return this.getTargetPointer().getTargets(game, source).contains(objectId);
}

public AssaultFormation(UUID ownerId, CardSetInfo setInfo) {
  super(ownerId, setInfo, new CardType[]{CardType.ENCHANTMENT}, "{1}{G}");
  // Each creature you control assigns combat damage equal to its toughness rather than its power.
  this.addAbility(new SimpleStaticAbility(Zone.BATTLEFIELD, new CombatDamageByToughnessEffect(StaticFilters.FILTER_PERMANENT_CREATURE, true)));
  // {G}: Target creature with defender can attack this turn as though it didn't have defender.
  Ability ability = new SimpleActivatedAbility(Zone.BATTLEFIELD, new CanAttackAsThoughItDidntHaveDefenderTargetEffect(Duration.EndOfTurn), new ManaCostsImpl("{G}"));
  ability.addTarget(new TargetCreaturePermanent(filter));
  this.addAbility(ability);
  // {2}{G}: Creatures you control get +0/+1 until end of turn.
  this.addAbility(new SimpleActivatedAbility(Zone.BATTLEFIELD, new BoostControlledEffect(0, 1, Duration.EndOfTurn), new ManaCostsImpl("{2}{G}")));
}