Merge branch 'master' into sol-7

Author: aalavandhan

contracts/UFragments.sol

@@ -58,15 +58,15 @@ contract UFragments is ERC20Detailed, Ownable {
     }
 
     uint256 private constant DECIMALS = 9;
-    uint256 private constant MAX_UINT256 = ~uint256(0);
+    uint256 private constant MAX_UINT256 = type(uint256).max;
     uint256 private constant INITIAL_FRAGMENTS_SUPPLY = 50 * 10**6 * 10**DECIMALS;
 
     // TOTAL_GONS is a multiple of INITIAL_FRAGMENTS_SUPPLY so that _gonsPerFragment is an integer.
     // Use the highest value that fits in a uint256 for max granularity.
     uint256 private constant TOTAL_GONS = MAX_UINT256 - (MAX_UINT256 % INITIAL_FRAGMENTS_SUPPLY);
 
     // MAX_SUPPLY = maximum integer < (sqrt(4*TOTAL_GONS + 1) - 1) / 2
-    uint256 private constant MAX_SUPPLY = ~uint128(0); // (2^128) - 1
+    uint256 private constant MAX_SUPPLY = type(uint128).max; // (2^128) - 1
 
     uint256 private _totalSupply;
     uint256 private _gonsPerFragment;
@@ -358,12 +358,7 @@ contract UFragments is ERC20Detailed, Ownable {
      */
     function decreaseAllowance(address spender, uint256 subtractedValue) external returns (bool) {
         uint256 oldValue = _allowedFragments[msg.sender][spender];
-        uint256 newValue;
-        if (subtractedValue >= oldValue) {
-            newValue = 0;
-        } else {
-            newValue = oldValue.sub(subtractedValue);
-        }
+        uint256 newValue = (subtractedValue >= oldValue) ? 0 : oldValue.sub(subtractedValue);
 
         _allowedFragments[msg.sender][spender] = newValue;
         emit Approval(msg.sender, spender, newValue);

contracts/UFragmentsPolicy.sol

@@ -83,7 +83,7 @@ contract UFragmentsPolicy is Ownable {
     // Both are 18 decimals fixed point numbers.
     uint256 private constant MAX_RATE = 10**6 * 10**DECIMALS;
     // MAX_SUPPLY = MAX_INT256 / MAX_RATE
-    uint256 private constant MAX_SUPPLY = ~(uint256(1) << 255) / MAX_RATE;
+    uint256 public constant MAX_SUPPLY = uint256(type(int256).max) / MAX_RATE;
 
     // This module orchestrates the rebase execution and downstream notification.
     address public orchestrator;