Fixed errors

contracts/interfaces/ILendingPool.sol

@@ -326,7 +326,6 @@ interface ILendingPool {
       uint256 currentStableDebt,
       uint256 currentVariableDebt,
       uint256 principalStableDebt,
-      uint256 principalVariableDebt,
       uint256 scaledVariableDebt,
       uint256 stableBorrowRate,
       uint256 liquidityRate,

contracts/lendingpool/LendingPool.sol

@@ -49,10 +49,9 @@ contract LendingPool is VersionedInitializable, ILendingPool {
   uint256 public constant UINT_MAX_VALUE = uint256(-1);
   uint256 public constant LENDINGPOOL_REVISION = 0x2;
 
-  ILendingPoolAddressesProvider public immutable ADDRESSES_PROVIDER;
-
   mapping(address => ReserveLogic.ReserveData) internal _reserves;
   mapping(address => UserConfiguration.Map) internal _usersConfig;
+  ILendingPoolAddressesProvider internal _addressesProvider;
 
   address[] internal _reservesList;
 
@@ -63,7 +62,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
    **/
   modifier onlyLendingPoolConfigurator {
     require(
-      ADDRESSES_PROVIDER.getLendingPoolConfigurator() == msg.sender,
+      _addressesProvider.getLendingPoolConfigurator() == msg.sender,
       Errors.CALLER_NOT_LENDING_POOL_CONFIGURATOR
     );
     _;
@@ -79,7 +78,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
    * @param provider the address of the LendingPoolAddressesProvider registry
    **/
   function initialize(ILendingPoolAddressesProvider provider) public initializer {
-    ADDRESSES_PROVIDER = provider;
+    _addressesProvider = provider;
   }
 
   /**
@@ -144,7 +143,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
       _reserves,
       _usersConfig[msg.sender],
       _reservesList,
-      ADDRESSES_PROVIDER.getPriceOracle()
+      _addressesProvider.getPriceOracle()
     );
 
     reserve.updateState();
@@ -271,10 +270,10 @@ contract LendingPool is VersionedInitializable, ILendingPool {
     if (interestRateMode == ReserveLogic.InterestRateMode.STABLE) {
       //burn stable rate tokens, mint variable rate tokens
       IStableDebtToken(reserve.stableDebtTokenAddress).burn(msg.sender, stableDebt);
-      IVariableDebtToken(reserve.variableDebtTokenAddress).mint(msg.sender, stableDebt);
+      IVariableDebtToken(reserve.variableDebtTokenAddress).mint(msg.sender, stableDebt, reserve.variableBorrowIndex);
     } else {
       //do the opposite
-      IVariableDebtToken(reserve.variableDebtTokenAddress).burn(msg.sender, variableDebt);
+      IVariableDebtToken(reserve.variableDebtTokenAddress).burn(msg.sender, variableDebt, reserve.variableBorrowIndex);
       IStableDebtToken(reserve.stableDebtTokenAddress).mint(
         msg.sender,
         variableDebt,
@@ -348,7 +347,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
       _reserves,
       _usersConfig[msg.sender],
       _reservesList,
-      ADDRESSES_PROVIDER.getPriceOracle()
+      _addressesProvider.getPriceOracle()
     );
 
     _usersConfig[msg.sender].setUsingAsCollateral(reserve.id, useAsCollateral);
@@ -376,7 +375,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
     uint256 purchaseAmount,
     bool receiveAToken
   ) external override {
-    address liquidationManager = ADDRESSES_PROVIDER.getLendingPoolLiquidationManager();
+    address liquidationManager = _addressesProvider.getLendingPoolLiquidationManager();
 
     //solium-disable-next-line
     (bool success, bytes memory result) = liquidationManager.delegatecall(
@@ -435,7 +434,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
     require(!_flashLiquidationLocked, Errors.REENTRANCY_NOT_ALLOWED);
     _flashLiquidationLocked = true;
 
-    address liquidationManager = ADDRESSES_PROVIDER.getLendingPoolLiquidationManager();
+    address liquidationManager = _addressesProvider.getLendingPoolLiquidationManager();
 
     //solium-disable-next-line
     (bool success, bytes memory result) = liquidationManager.delegatecall(
@@ -638,7 +637,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
       _reserves,
       _usersConfig[user],
       _reservesList,
-      ADDRESSES_PROVIDER.getPriceOracle()
+      _addressesProvider.getPriceOracle()
     );
 
     availableBorrowsETH = GenericLogic.calculateAvailableBorrowsETH(
@@ -657,7 +656,6 @@ contract LendingPool is VersionedInitializable, ILendingPool {
       uint256 currentStableDebt,
       uint256 currentVariableDebt,
       uint256 principalStableDebt,
-      uint256 variableBorrowIndex,
       uint256 scaledVariableDebt,
       uint256 stableBorrowRate,
       uint256 liquidityRate,
@@ -669,7 +667,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
 
     currentATokenBalance = IERC20(reserve.aTokenAddress).balanceOf(user);
     (currentStableDebt, currentVariableDebt) = Helpers.getUserCurrentDebt(user, reserve);
-    (principalStableDebt, principalVariableDebt) = Helpers.getUserPrincipalDebt(user, reserve);
+    principalStableDebt = IStableDebtToken(reserve.stableDebtTokenAddress).principalBalanceOf(user);
     scaledVariableDebt = IVariableDebtToken(reserve.variableDebtTokenAddress).scaledBalanceOf(user);
     liquidityRate = reserve.currentLiquidityRate;
     stableBorrowRate = IStableDebtToken(reserve.stableDebtTokenAddress).getUserStableRate(user);
@@ -677,7 +675,6 @@ contract LendingPool is VersionedInitializable, ILendingPool {
       user
     );
     usageAsCollateralEnabled = _usersConfig[user].isUsingAsCollateral(reserve.id);
-    variableBorrowIndex = IVariableDebtToken(reserve.variableDebtTokenAddress).getUserIndex(user);
   }
 
   function getReserves() external override view returns (address[] memory) {
@@ -784,7 +781,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
         _reserves,
         _usersConfig[user],
         _reservesList,
-        ADDRESSES_PROVIDER.getPriceOracle()
+        _addressesProvider.getPriceOracle()
       );
   }
 
@@ -799,7 +796,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
    * @dev returns the addresses provider
    **/
   function getAddressesProvider() external view returns (ILendingPoolAddressesProvider) {
-    return ADDRESSES_PROVIDER;
+    return _addressesProvider;
   }
 
   // internal functions
@@ -822,7 +819,7 @@ contract LendingPool is VersionedInitializable, ILendingPool {
     ReserveLogic.ReserveData storage reserve = _reserves[vars.asset];
     UserConfiguration.Map storage userConfig = _usersConfig[msg.sender];
 
-    address oracle = ADDRESSES_PROVIDER.getPriceOracle();
+    address oracle = _addressesProvider.getPriceOracle();
 
     uint256 amountInETH = IPriceOracleGetter(oracle).getAssetPrice(vars.asset).mul(vars.amount).div(
       10**reserve.configuration.getDecimals()

contracts/lendingpool/LendingPoolLiquidationManager.sol

@@ -234,8 +234,6 @@ contract LendingPoolLiquidationManager is VersionedInitializable {
     //update the principal reserve
     principalReserve.updateState();
 
-
-
     principalReserve.updateInterestRates(
       principal,
       principalReserve.aTokenAddress,
@@ -244,29 +242,19 @@ contract LendingPoolLiquidationManager is VersionedInitializable {
     );
 
     if (vars.userVariableDebt >= vars.actualAmountToLiquidate) {
-
+      IVariableDebtToken(principalReserve.variableDebtTokenAddress).burn(
-      address tokenAddress = principalReserve.variableDebtTokenAddress;
-
-      _mintToReserveTreasury(principalReserve, user, tokenAddress);
-
-      IVariableDebtToken(tokenAddress).burn(
         user,
-        vars.actualAmountToLiquidate
+        vars.actualAmountToLiquidate,
+        principalReserve.variableBorrowIndex
       );
     } else {
-
+      IVariableDebtToken(principalReserve.variableDebtTokenAddress).burn(
-      address tokenAddress = principalReserve.variableDebtTokenAddress;
-
-      _mintToReserveTreasury(principalReserve, user, tokenAddress);
-
-      IVariableDebtToken(tokenAddress).burn(
         user,
-        vars.userVariableDebt
+        vars.userVariableDebt,
+        principalReserve.variableBorrowIndex
       );
 
-      tokenAddress = principalReserve.stableDebtTokenAddress;
+      IStableDebtToken(principalReserve.stableDebtTokenAddress).burn(
-
-      IStableDebtToken(tokenAddress).burn(
         user,
         vars.actualAmountToLiquidate.sub(vars.userVariableDebt)
       );
@@ -288,7 +276,12 @@ contract LendingPoolLiquidationManager is VersionedInitializable {
       );
 
       //burn the equivalent amount of atoken
-      vars.collateralAtoken.burn(user, msg.sender, vars.maxCollateralToLiquidate, collateralReserve.liquidityIndex);
+      vars.collateralAtoken.burn(
+        user,
+        msg.sender,
+        vars.maxCollateralToLiquidate,
+        collateralReserve.liquidityIndex
+      );
     }
 
     //transfers the principal currency to the aToken
@@ -408,7 +401,12 @@ contract LendingPoolLiquidationManager is VersionedInitializable {
     //updating collateral reserve indexes
     collateralReserve.updateState();
 
-    vars.collateralAtoken.burn(user, receiver, vars.maxCollateralToLiquidate, collateralReserve.liquidityIndex);
+    vars.collateralAtoken.burn(
+      user,
+      receiver,
+      vars.maxCollateralToLiquidate,
+      collateralReserve.liquidityIndex
+    );
 
     if (vars.userCollateralBalance == vars.maxCollateralToLiquidate) {
       usersConfig[user].setUsingAsCollateral(collateralReserve.id, false);
@@ -433,10 +431,15 @@ contract LendingPoolLiquidationManager is VersionedInitializable {
     if (vars.userVariableDebt >= vars.actualAmountToLiquidate) {
       IVariableDebtToken(debtReserve.variableDebtTokenAddress).burn(
         user,
-        vars.actualAmountToLiquidate
+        vars.actualAmountToLiquidate,
+        debtReserve.variableBorrowIndex
       );
     } else {
-      IVariableDebtToken(debtReserve.variableDebtTokenAddress).burn(user, vars.userVariableDebt);
+      IVariableDebtToken(debtReserve.variableDebtTokenAddress).burn(
+        user,
+        vars.userVariableDebt,
+        debtReserve.variableBorrowIndex
+      );
       IStableDebtToken(debtReserve.stableDebtTokenAddress).burn(
         user,
         vars.actualAmountToLiquidate.sub(vars.userVariableDebt)
@@ -530,19 +533,4 @@ contract LendingPoolLiquidationManager is VersionedInitializable {
     }
     return (collateralAmount, principalAmountNeeded);
   }
-
-  function _mintToReserveTreasury(ReserveLogic.ReserveData storage reserve, address user, address debtTokenAddress) internal {
-    
-    uint256 currentPrincipalBalance = DebtTokenBase(debtTokenAddress).principalBalanceOf(user);
-    //calculating the interest accrued since the last borrow and minting the equivalent amount to the reserve factor
-    if(currentPrincipalBalance > 0){
-
-      uint256 balanceIncrease = IERC20(debtTokenAddress).balanceOf(user).sub(currentPrincipalBalance);
-
-      uint256 amountForReserveFactor = balanceIncrease.percentMul(reserve.configuration.getReserveFactor());
-
-      IAToken(reserve.aTokenAddress).mintToReserve(amountForReserveFactor);      
-    }    
-
-  }
 }

contracts/libraries/helpers/Helpers.sol

@@ -26,21 +26,4 @@ library Helpers {
       DebtTokenBase(reserve.variableDebtTokenAddress).balanceOf(user)
     );
   }
-
-  /**
-   * @dev fetches the user principal stable and variable debt balances
-   * @param user the user
-   * @param reserve the reserve object
-   * @return the stable and variable debt balance
-   **/
-  function getUserPrincipalDebt(address user, ReserveLogic.ReserveData storage reserve)
-    internal
-    view
-    returns (uint256, uint256)
-  {
-    return (
-      DebtTokenBase(reserve.stableDebtTokenAddress).principalBalanceOf(user),
-      DebtTokenBase(reserve.variableDebtTokenAddress).principalBalanceOf(user)
-    );
-  }
 }

contracts/libraries/logic/ReserveLogic.sol

@@ -6,11 +6,13 @@ import {IERC20} from '@openzeppelin/contracts/token/ERC20/IERC20.sol';
 import {MathUtils} from '../math/MathUtils.sol';
 import {IPriceOracleGetter} from '../../interfaces/IPriceOracleGetter.sol';
 import {SafeERC20} from '@openzeppelin/contracts/token/ERC20/SafeERC20.sol';
+import {IAToken} from '../../tokenization/interfaces/IAToken.sol';
 import {IStableDebtToken} from '../../tokenization/interfaces/IStableDebtToken.sol';
 import {IVariableDebtToken} from '../../tokenization/interfaces/IVariableDebtToken.sol';
 import {ReserveConfiguration} from '../configuration/ReserveConfiguration.sol';
 import {IReserveInterestRateStrategy} from '../../interfaces/IReserveInterestRateStrategy.sol';
 import {WadRayMath} from '../math/WadRayMath.sol';
+import {PercentageMath} from '../math/PercentageMath.sol';
 import {Errors} from '../helpers/Errors.sol';
 
 /**
@@ -21,6 +23,7 @@ import {Errors} from '../helpers/Errors.sol';
 library ReserveLogic {
   using SafeMath for uint256;
   using WadRayMath for uint256;
+  using PercentageMath for uint256;
   using SafeERC20 for IERC20;
 
   /**
@@ -63,14 +66,12 @@ library ReserveLogic {
     //the current stable borrow rate. Expressed in ray
     uint128 currentStableBorrowRate;
     uint40 lastUpdateTimestamp;
-   
     //tokens addresses
     address aTokenAddress;
     address stableDebtTokenAddress;
     address variableDebtTokenAddress;
     //address of the interest rate strategy
     address interestRateStrategyAddress;
-
     //the id of the reserve. Represents the position in the list of the active reserves
     uint8 id;
   }
@@ -127,8 +128,14 @@ library ReserveLogic {
    * @param reserve the reserve object
    **/
   function updateState(ReserveData storage reserve) internal {
-    _mintToTreasury(reserve);
+    address stableDebtToken = reserve.stableDebtTokenAddress;
-    _updateIndexes(reserve);
+    address variableDebtToken = reserve.variableDebtTokenAddress;
+    uint256 variableBorrowIndex = reserve.variableBorrowIndex;
+    uint256 liquidityIndex = reserve.liquidityIndex;
+    uint40 timestamp = reserve.lastUpdateTimestamp;
+
+    _mintToTreasury(reserve, stableDebtToken, variableDebtToken, liquidityIndex,  variableBorrowIndex, timestamp);
+    _updateIndexes(reserve, variableDebtToken, liquidityIndex, variableBorrowIndex, timestamp);
   }
 
   /**
@@ -243,28 +250,70 @@ library ReserveLogic {
     );
   }
 
-  function _mintToTreasury(ReserveData storage reserve) internal {
+  struct MintToTreasuryLocalVars {
-    
+    uint256 currentTotalDebt;
-    address stableDebtToken = reserve.stableDebtTokenAddress;
+    uint256 principalStableDebt;
-    address variableDebtToken = reserve.variableDebtTokenAddress;
+    uint256 avgStableRate;
+    uint256 scaledVariableDebt;
+    uint256 cumulatedStableInterest;
+    uint256 variableDebtOnLastUpdate;
+    uint256 stableDebtOnLastUpdate;
+    uint256 totalInterestAccrued;
+    uint256 amountToMint;
+    uint256 reserveFactor;
+  }
 
-    uint256 currentVariableDebt = IERC20(variableDebtToken).totalSupply();
+  function _mintToTreasury(
-    uint256 currentStableDebt = IERC20(stableDebtToken).totalSupply();
+    ReserveData storage reserve,
+    address stableDebtToken,
+    address variableDebtToken,
+    uint256 liquidityIndex,
+    uint256 variableBorrowIndex,
+    uint40 lastUpdateTimestamp
+  ) internal {
+   
+    MintToTreasuryLocalVars memory vars;
 
-    uint256 principalStableDebt = IStableDebtToken(stableDebtToken).principalTotalSupply();
+    vars.reserveFactor = reserve.configuration.getReserveFactor();
-    uint256 scaledVariableDebt = IVariableDebtToken(variableDebtToken).scaledTotalSupply();
+
-    
+    if(vars.reserveFactor == 0){
-    
+      return;
-    
+    }
+
+    vars.currentTotalDebt = IERC20(variableDebtToken).totalSupply().add(IERC20(stableDebtToken).totalSupply());
+
+    (vars.principalStableDebt, vars.avgStableRate) = IStableDebtToken(stableDebtToken)
+      .getPrincipalSupplyAndAvgRate();
+
+    vars.scaledVariableDebt = IVariableDebtToken(variableDebtToken).scaledTotalSupply();
+
+    vars.cumulatedStableInterest = MathUtils.calculateCompoundedInterest(
+      vars.avgStableRate,
+      lastUpdateTimestamp
+    );
+
+    vars.variableDebtOnLastUpdate = vars.scaledVariableDebt.rayMul(variableBorrowIndex);
+    vars.stableDebtOnLastUpdate = vars.principalStableDebt.rayMul(vars.cumulatedStableInterest);
+
+    vars.totalInterestAccrued =vars.currentTotalDebt.sub(vars.variableDebtOnLastUpdate.add(vars.stableDebtOnLastUpdate));
+
+    vars.amountToMint = vars.totalInterestAccrued.percentMul(vars.reserveFactor);
+
+    IAToken(reserve.aTokenAddress).mintToTreasury(vars.amountToMint, liquidityIndex);      
 
   }
 
-  function _updateIndexes(ReserveData storage reserve) internal {
+  function _updateIndexes(
+    ReserveData storage reserve,
+    address variableDebtToken,
+    uint256 liquidityIndex,
+    uint256 variableBorrowIndex,
+    uint40 lastUpdateTimestamp
+  ) internal {
     uint256 currentLiquidityRate = reserve.currentLiquidityRate;
 
     //only cumulating if there is any income being produced
     if (currentLiquidityRate > 0) {
-      uint40 lastUpdateTimestamp = reserve.lastUpdateTimestamp;
       uint256 cumulatedLiquidityInterest = MathUtils.calculateLinearInterest(
         currentLiquidityRate,
         lastUpdateTimestamp
@@ -276,12 +325,12 @@ library ReserveLogic {
 
       //as the liquidity rate might come only from stable rate loans, we need to ensure
       //that there is actual variable debt before accumulating
-      if (IERC20(reserve.variableDebtTokenAddress).totalSupply() > 0) {
+      if (IERC20(variableDebtToken).totalSupply() > 0) {
         uint256 cumulatedVariableBorrowInterest = MathUtils.calculateCompoundedInterest(
           reserve.currentVariableBorrowRate,
           lastUpdateTimestamp
         );
-        index = cumulatedVariableBorrowInterest.rayMul(reserve.variableBorrowIndex);
+        index = cumulatedVariableBorrowInterest.rayMul(variableBorrowIndex);
         require(index < (1 << 128), Errors.VARIABLE_BORROW_INDEX_OVERFLOW);
         reserve.variableBorrowIndex = uint128(index);
       }

contracts/tokenization/AToken.sol

@@ -105,8 +105,7 @@ contract AToken is VersionedInitializable, ERC20, IAToken {
     emit Mint(user, amount, index);
   }
 
-  function mintToReserve(uint256 amount) external override onlyLendingPool {
+  function mintToTreasury(uint256 amount, uint256 index) external override onlyLendingPool {
-      uint256 index = _pool.getReserveNormalizedIncome(UNDERLYING_ASSET_ADDRESS);
       _mint(RESERVE_TREASURY_ADDRESS, amount.div(index));
   }
 

contracts/tokenization/StableDebtToken.sol

@@ -68,7 +68,7 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
    * @return the accumulated debt of the user
    **/
   function balanceOf(address account) public virtual override view returns (uint256) {
-    uint256 accountBalance = principalBalanceOf(account);
+    uint256 accountBalance = super.balanceOf(account);
     uint256 stableRate = _usersData[account];
     if (accountBalance == 0) {
       return 0;
@@ -125,7 +125,6 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
     //solium-disable-next-line
     _totalSupplyTimestamp = _timestamps[user] = uint40(block.timestamp);
 
-
     //calculates the updated average stable rate
     _avgStableRate = _avgStableRate
       .rayMul(vars.supplyBeforeMint.wadToRay())
@@ -185,15 +184,22 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
     emit BurnDebt(user, amount, previousBalance, currentBalance, balanceIncrease);
   }
 
-
   /**
    * @dev Calculates the increase in balance since the last user interaction
    * @param user The address of the user for which the interest is being accumulated
    * @return The previous principal balance, the new principal balance, the balance increase
    * and the new user index
    **/
-  function _calculateBalanceIncrease(address user) internal view returns (uint256, uint256, uint256) {
+  function _calculateBalanceIncrease(address user)
-    uint256 previousPrincipalBalance = principalBalanceOf(user);
+    internal
+    view
+    returns (
+      uint256,
+      uint256,
+      uint256
+    )
+  {
+    uint256 previousPrincipalBalance = super.balanceOf(user);
 
     if (previousPrincipalBalance == 0) {
       return (0, 0, 0);
@@ -209,11 +215,11 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
     );
   }
 
-  function principalTotalSupply() public override view returns(uint256) {
+  function getPrincipalSupplyAndAvgRate() public override view returns (uint256, uint256) {
-    return super.totalSupply();
+    return (super.totalSupply(), _avgStableRate);
   }
-  
+
-  function totalSupply() public override view returns(uint256) {
+  function totalSupply() public override view returns (uint256) {
     uint256 principalSupply = super.totalSupply();
     if (principalSupply == 0) {
       return 0;
@@ -225,4 +231,11 @@ contract StableDebtToken is IStableDebtToken, DebtTokenBase {
     return principalSupply.rayMul(cumulatedInterest);
   }
 
+  /**
+   * @dev Returns the principal debt balance of the user from
+   * @return The debt balance of the user since the last burn/mint action
+   **/
+  function principalBalanceOf(address user) external virtual override view returns (uint256) {
+    return super.balanceOf(user);
+  }
 }

contracts/tokenization/VariableDebtToken.sol

@@ -39,7 +39,7 @@ contract VariableDebtToken is DebtTokenBase, IVariableDebtToken {
    * @return the debt balance of the user
    **/
   function balanceOf(address user) public virtual override view returns (uint256) {
-    uint256 scaledBalance = super.principalBalanceOf(user);
+    uint256 scaledBalance = super.balanceOf(user);
     
     if (scaledBalance == 0) {
       return 0;

contracts/tokenization/base/DebtTokenBase.sol

@@ -64,14 +64,6 @@ abstract contract DebtTokenBase is ERC20, VersionedInitializable {
     return UNDERLYING_ASSET;
   }
 
-  /**
-   * @dev Returns the principal debt balance of the user from
-   * @return The debt balance of the user since the last burn/mint action
-   **/
-  function principalBalanceOf(address user) public virtual view returns (uint256) {
-    return super.balanceOf(user);
-  }
-
   /**
    * @dev Being non transferrable, the debt token does not implement any of the
    * standard ERC20 functions for transfer and allowance.

contracts/tokenization/interfaces/IAToken.sol

@@ -62,12 +62,11 @@ interface IAToken is IERC20 {
   function mint(address user, uint256 amount, uint256 index) external;
 
   /**
-   * @dev mints aTokens to reserve, based on the reserveFactor value
+   * @dev mints aTokens to the reserve treasury
-   * only lending pools can call this function
+   * @param amount the amount to mint
-   * @param amount the amount of tokens to mint
+   * @param index the liquidity index of the reserve
-   */
+   **/
-  function mintToReserve(uint256 amount) external;
+  function mintToTreasury(uint256 amount, uint256 index) external;
-
 
   /**
    * @dev transfers tokens in the event of a borrow being liquidated, in case the liquidators reclaims the aToken
@@ -104,6 +103,7 @@ interface IAToken is IERC20 {
    * @param amount the amount to transfer
    * @return the amount transferred
    **/
-
   function transferUnderlyingTo(address user, uint256 amount) external returns (uint256);
+
+
 }

contracts/tokenization/interfaces/IStableDebtToken.sol

@@ -86,7 +86,14 @@ interface IStableDebtToken {
   function getUserLastUpdated(address user) external view returns (uint40);
 
   /**
-   * @dev returns the principal total supply 
+   * @dev returns the principal total supply and the average stable rate
    **/
-  function principalTotalSupply() external view returns (uint40);
+  function getPrincipalSupplyAndAvgRate() external view returns (uint256, uint256);
+
+    /**
+   * @dev Returns the principal debt balance of the user 
+   * @return The debt balance of the user since the last burn/mint action
+   **/
+  function principalBalanceOf(address user) external view returns (uint256);
+
 }

test/helpers/utils/calculations.ts

@@ -273,19 +273,16 @@ export const calcExpectedReserveDataAfterBorrow = (
 
   const amountBorrowedBN = new BigNumber(amountBorrowed);
 
-  const userStableBorrowBalance = calcExpectedStableDebtTokenBalance(
+  const userStableDebt = calcExpectedStableDebtTokenBalance(userDataBeforeAction, txTimestamp);
-    userDataBeforeAction,
-    txTimestamp
-  );
 
-  const userVariableBorrowBalance = calcExpectedVariableDebtTokenBalance(
+  const userVariableDebt = calcExpectedVariableDebtTokenBalance(
     reserveDataBeforeAction,
     userDataBeforeAction,
     txTimestamp
   );
 
   if (borrowRateMode == RateMode.Stable) {
-    const debtAccrued = userStableBorrowBalance.minus(userDataBeforeAction.principalStableDebt);
+    const debtAccrued = userStableDebt.minus(userDataBeforeAction.principalStableDebt);
 
     expectedReserveData.totalLiquidity = reserveDataBeforeAction.totalLiquidity.plus(debtAccrued);
 
@@ -301,7 +298,11 @@ export const calcExpectedReserveDataAfterBorrow = (
     );
     expectedReserveData.totalBorrowsVariable = reserveDataBeforeAction.totalBorrowsVariable;
   } else {
-    const debtAccrued = userVariableBorrowBalance.minus(userDataBeforeAction.principalVariableDebt);
+    const variableDebtBefore = userDataBeforeAction.scaledVariableDebt.rayMul(
+      reserveDataBeforeAction.variableBorrowIndex
+    );
+
+    const debtAccrued = userVariableDebt.minus(variableDebtBefore);
     expectedReserveData.totalLiquidity = reserveDataBeforeAction.totalLiquidity.plus(debtAccrued);
     expectedReserveData.totalBorrowsVariable = reserveDataBeforeAction.totalBorrowsVariable
       .plus(amountBorrowedBN)
@@ -362,12 +363,9 @@ export const calcExpectedReserveDataAfterRepay = (
 
   let amountRepaidBN = new BigNumber(amountRepaid);
 
-  const userStableBorrowBalance = calcExpectedStableDebtTokenBalance(
+  const userStableDebt = calcExpectedStableDebtTokenBalance(userDataBeforeAction, txTimestamp);
-    userDataBeforeAction,
-    txTimestamp
-  );
 
-  const userVariableBorrowBalance = calcExpectedVariableDebtTokenBalance(
+  const userVariableDebt = calcExpectedVariableDebtTokenBalance(
     reserveDataBeforeAction,
     userDataBeforeAction,
     txTimestamp
@@ -376,14 +374,14 @@ export const calcExpectedReserveDataAfterRepay = (
   //if amount repaid = MAX_UINT_AMOUNT, user is repaying everything
   if (amountRepaidBN.abs().eq(MAX_UINT_AMOUNT)) {
     if (borrowRateMode == RateMode.Stable) {
-      amountRepaidBN = userStableBorrowBalance;
+      amountRepaidBN = userStableDebt;
     } else {
-      amountRepaidBN = userVariableBorrowBalance;
+      amountRepaidBN = userVariableDebt;
     }
   }
 
   if (borrowRateMode == RateMode.Stable) {
-    const debtAccrued = userStableBorrowBalance.minus(userDataBeforeAction.principalStableDebt);
+    const debtAccrued = userStableDebt.minus(userDataBeforeAction.principalStableDebt);
 
     expectedReserveData.totalLiquidity = reserveDataBeforeAction.totalLiquidity.plus(debtAccrued);
 
@@ -399,7 +397,11 @@ export const calcExpectedReserveDataAfterRepay = (
     );
     expectedReserveData.totalBorrowsVariable = reserveDataBeforeAction.totalBorrowsVariable;
   } else {
-    const debtAccrued = userVariableBorrowBalance.minus(userDataBeforeAction.principalVariableDebt);
+    const variableDebtBefore = userDataBeforeAction.scaledVariableDebt.rayMul(
+      reserveDataBeforeAction.variableBorrowIndex
+    );
+
+    const debtAccrued = userVariableDebt.minus(variableDebtBefore);
 
     expectedReserveData.totalLiquidity = reserveDataBeforeAction.totalLiquidity.plus(debtAccrued);
 
@@ -477,7 +479,7 @@ export const calcExpectedUserDataAfterBorrow = (
     const debtAccrued = currentStableDebt.minus(userDataBeforeAction.principalStableDebt);
 
     expectedUserData.principalStableDebt = currentStableDebt.plus(amountBorrowed);
-    expectedUserData.principalVariableDebt = userDataBeforeAction.principalVariableDebt;
+    expectedUserData.scaledVariableDebt = userDataBeforeAction.scaledVariableDebt;
 
     expectedUserData.stableBorrowRate = calcExpectedUserStableRate(
       userDataBeforeAction.principalStableDebt.plus(debtAccrued),
@@ -510,8 +512,8 @@ export const calcExpectedUserDataAfterBorrow = (
     expectedDataAfterAction,
     {
       ...userDataBeforeAction,
-      currentVariableDebt: expectedUserData.principalVariableDebt,
+      currentVariableDebt: expectedUserData.scaledVariableDebt.rayMul(reserveDataBeforeAction.variableBorrowIndex),
-      principalVariableDebt: expectedUserData.principalVariableDebt,
+      scaledVariableDebt: expectedUserData.scaledVariableDebt,
       variableBorrowIndex:
         interestRateMode == RateMode.Variable
           ? expectedDataAfterAction.variableBorrowIndex
@@ -520,7 +522,7 @@ export const calcExpectedUserDataAfterBorrow = (
     currentTimestamp
   );
 
-  if (expectedUserData.principalVariableDebt.eq(0)) {
+  if (expectedUserData.scaledVariableDebt.eq(0)) {
     expectedUserData.variableBorrowIndex = new BigNumber(0);
   } else {
     expectedUserData.variableBorrowIndex =
@@ -539,7 +541,7 @@ export const calcExpectedUserDataAfterBorrow = (
     currentTimestamp
   );
   expectedUserData.scaledATokenBalance = userDataBeforeAction.scaledATokenBalance;
-  
+
   expectedUserData.walletBalance = userDataBeforeAction.walletBalance.plus(amountBorrowed);
 
   return expectedUserData;
@@ -623,7 +625,7 @@ export const calcExpectedUserDataAfterRepay = (
     txTimestamp
   );
   expectedUserData.scaledATokenBalance = userDataBeforeAction.scaledATokenBalance;
- 
+
   if (user === onBehalfOf) {
     expectedUserData.walletBalance = userDataBeforeAction.walletBalance.minus(totalRepaid);
   } else {
@@ -657,51 +659,52 @@ export const calcExpectedReserveDataAfterSwapRateMode = (
 
   expectedReserveData.address = reserveDataBeforeAction.address;
 
-  const variableBorrowBalance = calcExpectedVariableDebtTokenBalance(
+  const variableDebt = calcExpectedVariableDebtTokenBalance(
     reserveDataBeforeAction,
     userDataBeforeAction,
     txTimestamp
   );
 
-  const stableBorrowBalance = calcExpectedStableDebtTokenBalance(userDataBeforeAction, txTimestamp);
+  const stableDebt = calcExpectedStableDebtTokenBalance(userDataBeforeAction, txTimestamp);
 
   expectedReserveData.availableLiquidity = reserveDataBeforeAction.availableLiquidity;
 
   if (rateMode === RateMode.Stable) {
     //swap user stable debt to variable
-    const debtAccrued = stableBorrowBalance.minus(userDataBeforeAction.principalStableDebt);
+    const debtAccrued = stableDebt.minus(userDataBeforeAction.principalStableDebt);
 
     expectedReserveData.totalLiquidity = reserveDataBeforeAction.totalLiquidity.plus(debtAccrued);
 
     expectedReserveData.averageStableBorrowRate = calcExpectedAverageStableBorrowRate(
       reserveDataBeforeAction.averageStableBorrowRate,
       reserveDataBeforeAction.totalBorrowsStable.plus(debtAccrued),
-      stableBorrowBalance.negated(),
+      stableDebt.negated(),
       userDataBeforeAction.stableBorrowRate
     );
 
     expectedReserveData.totalBorrowsVariable = reserveDataBeforeAction.totalBorrowsVariable.plus(
-      stableBorrowBalance
+      stableDebt
     );
 
     expectedReserveData.totalBorrowsStable = reserveDataBeforeAction.totalBorrowsStable.minus(
       userDataBeforeAction.principalStableDebt
     );
   } else {
-    const debtAccrued = variableBorrowBalance.minus(userDataBeforeAction.principalVariableDebt);
+    const totalDebtBefore = userDataBeforeAction.scaledVariableDebt.rayMul(reserveDataBeforeAction.variableBorrowIndex);
+    const debtAccrued = variableDebt.minus(totalDebtBefore);
 
     expectedReserveData.totalLiquidity = reserveDataBeforeAction.totalLiquidity.plus(debtAccrued);
-    expectedReserveData.totalBorrowsVariable = reserveDataBeforeAction.totalBorrowsVariable.minus(
+    
-      userDataBeforeAction.principalVariableDebt
+    expectedReserveData.totalBorrowsVariable = reserveDataBeforeAction.totalBorrowsVariable;
-    );
+    
 
     expectedReserveData.totalBorrowsStable = reserveDataBeforeAction.totalBorrowsStable.plus(
-      variableBorrowBalance
+      variableDebt
     );
     expectedReserveData.averageStableBorrowRate = calcExpectedAverageStableBorrowRate(
       reserveDataBeforeAction.averageStableBorrowRate,
       reserveDataBeforeAction.totalBorrowsStable,
-      variableBorrowBalance,
+      variableDebt,
       reserveDataBeforeAction.stableBorrowRate
     );
   }
@@ -926,9 +929,7 @@ const calcExpectedATokenBalance = (
 ) => {
   const index = calcExpectedReserveNormalizedIncome(reserveDataBeforeAction, currentTimestamp);
 
-  const {
+  const {scaledATokenBalance: scaledBalanceBeforeAction} = userDataBeforeAction;
-    scaledATokenBalance: scaledBalanceBeforeAction,
-  } = userDataBeforeAction;
 
   return scaledBalanceBeforeAction.rayMul(index);
 };
@@ -969,8 +970,7 @@ export const calcExpectedVariableDebtTokenBalance = (
 ) => {
   const debt = calcExpectedReserveNormalizedDebt(reserveDataBeforeAction, currentTimestamp);
 
-  const { scaledVariableDebt } = userDataBeforeAction;
+  const {scaledVariableDebt} = userDataBeforeAction;
-
 
   return scaledVariableDebt.rayMul(debt);
 };

test/helpers/utils/helpers.ts

@@ -79,7 +79,6 @@ export const getUserData = async (
     currentStableDebt: new BigNumber(userData.currentStableDebt.toString()),
     currentVariableDebt: new BigNumber(userData.currentVariableDebt.toString()),
     principalStableDebt: new BigNumber(userData.principalStableDebt.toString()),
-    principalVariableDebt: new BigNumber(userData.principalVariableDebt.toString()),
     scaledVariableDebt: new BigNumber(userData.scaledVariableDebt.toString()),
     stableBorrowRate: new BigNumber(userData.stableBorrowRate.toString()),
     liquidityRate: new BigNumber(userData.liquidityRate.toString()),

test/helpers/utils/interfaces/index.ts

@@ -6,7 +6,6 @@ export interface UserReserveData {
   currentStableDebt: BigNumber;
   currentVariableDebt: BigNumber;
   principalStableDebt: BigNumber;
-  principalVariableDebt: BigNumber;
   scaledVariableDebt: BigNumber;
   liquidityRate: BigNumber;
   stableBorrowRate: BigNumber;

test/scenario.spec.ts

@@ -10,7 +10,7 @@ import {executeStory} from './helpers/scenario-engine';
 
 const scenarioFolder = './test/helpers/scenarios/';
 
-const selectedScenarios: string[] = [''];
+const selectedScenarios: string[] = ['deposit.json'];
 
 fs.readdirSync(scenarioFolder).forEach((file) => {
   if (selectedScenarios.length > 0 && !selectedScenarios.includes(file)) return;

test/variable-debt-token.spec.ts

@@ -18,7 +18,7 @@ makeSuite('Variable debt token tests', (testEnv: TestEnv) => {
       daiVariableDebtTokenAddress
     );
 
-    await expect(variableDebtContract.mint(deployer.address, '1')).to.be.revertedWith(
+    await expect(variableDebtContract.mint(deployer.address, '1', '1')).to.be.revertedWith(
       CALLER_MUST_BE_LENDING_POOL
     );
   });
@@ -34,7 +34,7 @@ makeSuite('Variable debt token tests', (testEnv: TestEnv) => {
       daiVariableDebtTokenAddress
     );
 
-    await expect(variableDebtContract.burn(deployer.address, '1')).to.be.revertedWith(
+    await expect(variableDebtContract.burn(deployer.address, '1', '1')).to.be.revertedWith(
       CALLER_MUST_BE_LENDING_POOL
     );
   });