fix: Consistently use from when burning.

contracts/interfaces/IStableDebtToken.sol

@@ -34,15 +34,15 @@ interface IStableDebtToken is IInitializableDebtToken {
 
   /**
    * @dev Emitted when new stable debt is burned
-   * @param user The address of the user
+   * @param from The address from which the debt will be burned
    * @param amount The amount being burned (user entered amount - balance increase from interest)
    * @param currentBalance The current balance of the user
    * @param balanceIncrease The the increase in balance since the last action of the user
    * @param avgStableRate The next average stable rate after the burning
    * @param newTotalSupply The next total supply of the stable debt token after the action
    **/
   event Burn(
-    address indexed user,
+    address indexed from,
     uint256 amount,
     uint256 currentBalance,
     uint256 balanceIncrease,
@@ -82,12 +82,12 @@ interface IStableDebtToken is IInitializableDebtToken {
    * and the rate of the previous debt
    * @dev In some instances, a burn transaction will emit a mint event
    * if the amount to burn is less than the interest the user earned
-   * @param user The address of the user getting his debt burned
+   * @param from The address from which the debt will be burned
    * @param amount The amount of debt tokens getting burned
    * @return The total stable debt
    * @return The average stable borrow rate
    **/
-  function burn(address user, uint256 amount) external returns (uint256, uint256);
+  function burn(address from, uint256 amount) external returns (uint256, uint256);
 
   /**
    * @notice Returns the average rate of all the stable rate loans.

contracts/interfaces/IVariableDebtToken.sol

@@ -31,13 +31,13 @@ interface IVariableDebtToken is IScaledBalanceToken, IInitializableDebtToken {
    * @notice Burns user variable debt
    * @dev In some instances, a burn transaction will emit a mint event
    * if the amount to burn is less than the interest that the user accrued
-   * @param user The user which debt is burnt
+   * @param from The address from which the debt will be burned
    * @param amount The amount getting burned
    * @param index The variable debt index of the reserve
    * @return The scaled total debt of the reserve
    **/
   function burn(
-    address user,
+    address from,
     uint256 amount,
     uint256 index
   ) external returns (uint256);

contracts/protocol/tokenization/StableDebtToken.sol

@@ -183,18 +183,18 @@ contract StableDebtToken is DebtTokenBase, IncentivizedERC20, IStableDebtToken {
   }
 
   /// @inheritdoc IStableDebtToken
-  function burn(address user, uint256 amount)
+  function burn(address from, uint256 amount)
     external
     override
     onlyPool
     returns (uint256, uint256)
   {
-    (, uint256 currentBalance, uint256 balanceIncrease) = _calculateBalanceIncrease(user);
+    (, uint256 currentBalance, uint256 balanceIncrease) = _calculateBalanceIncrease(from);
 
     uint256 previousSupply = totalSupply();
     uint256 nextAvgStableRate = 0;
     uint256 nextSupply = 0;
-    uint256 userStableRate = _userState[user].additionalData;
+    uint256 userStableRate = _userState[from].additionalData;
 
     // Since the total supply and each single user debt accrue separately,
     // there might be accumulation errors so that the last borrower repaying
@@ -221,22 +221,22 @@ contract StableDebtToken is DebtTokenBase, IncentivizedERC20, IStableDebtToken {
     }
 
     if (amount == currentBalance) {
-      _userState[user].additionalData = 0;
-      _timestamps[user] = 0;
+      _userState[from].additionalData = 0;
+      _timestamps[from] = 0;
     } else {
       //solium-disable-next-line
-      _timestamps[user] = uint40(block.timestamp);
+      _timestamps[from] = uint40(block.timestamp);
     }
     //solium-disable-next-line
     _totalSupplyTimestamp = uint40(block.timestamp);
 
     if (balanceIncrease > amount) {
       uint256 amountToMint = balanceIncrease - amount;
-      _mint(user, amountToMint, previousSupply);
-      emit Transfer(address(0), user, amountToMint);
+      _mint(from, amountToMint, previousSupply);
+      emit Transfer(address(0), from, amountToMint);
       emit Mint(
-        user,
-        user,
+        from,
+        from,
         amountToMint,
         currentBalance,
         balanceIncrease,
@@ -246,9 +246,9 @@ contract StableDebtToken is DebtTokenBase, IncentivizedERC20, IStableDebtToken {
       );
     } else {
       uint256 amountToBurn = amount - balanceIncrease;
-      _burn(user, amountToBurn, previousSupply);
-      emit Transfer(user, address(0), amountToBurn);
-      emit Burn(user, amountToBurn, currentBalance, balanceIncrease, nextAvgStableRate, nextSupply);
+      _burn(from, amountToBurn, previousSupply);
+      emit Transfer(from, address(0), amountToBurn);
+      emit Burn(from, amountToBurn, currentBalance, balanceIncrease, nextAvgStableRate, nextSupply);
     }
 
     return (nextSupply, nextAvgStableRate);

contracts/protocol/tokenization/VariableDebtToken.sol

@@ -98,11 +98,11 @@ contract VariableDebtToken is DebtTokenBase, ScaledBalanceTokenBase, IVariableDe
 
   /// @inheritdoc IVariableDebtToken
   function burn(
-    address user,
+    address from,
     uint256 amount,
     uint256 index
   ) external override onlyPool returns (uint256) {
-    _burnScaled(user, address(0), amount, index);
+    _burnScaled(from, address(0), amount, index);
     return scaledTotalSupply();
   }