Merge branch 'fix/89-available-liquidity' into 'master'

Fixes #89

Closes #89

See merge request aave-tech/protocol-v2!103

contracts/lendingpool/LendingPool.sol

@@ -882,6 +882,7 @@ contract LendingPool is VersionedInitializable, ILendingPool, LendingPoolStorage
     );
 
     ValidationLogic.validateBorrow(
+      vars.asset,
       reserve,
       vars.onBehalfOf,
       vars.amount,

contracts/libraries/logic/ValidationLogic.sol

@@ -104,6 +104,7 @@ library ValidationLogic {
 
   /**
    * @dev validates a borrow.
+   * @param asset the address of the asset to borrow
    * @param reserve the reserve state from which the user is borrowing
    * @param userAddress the address of the user
    * @param amount the amount to be borrowed
@@ -117,6 +118,7 @@ library ValidationLogic {
    */
 
   function validateBorrow(
+    address asset,
     ReserveLogic.ReserveData storage reserve,
     address userAddress,
     uint256 amount,
@@ -203,6 +205,8 @@ library ValidationLogic {
         Errors.CALLATERAL_SAME_AS_BORROWING_CURRENCY
       );
 
+      vars.availableLiquidity = IERC20(asset).balanceOf(reserve.aTokenAddress);
+
       //calculate the max available loan size in stable rate mode as a percentage of the
       //available liquidity
       uint256 maxLoanSizeStable = vars.availableLiquidity.percentMul(maxStableLoanPercent);