refactor: update to solidity 0.6.12 (#277)

* refactor: update to solidity 0.6.12

* chore: update solhint version

* docs: update contribution guidelines with new version

* refactor: remove extra slash on comment

.solhint.json

@@ -1,7 +1,7 @@
 {
   "extends": "solhint:recommended",
   "rules": {
-    "compiler-version": ["error", "0.6.8"],
+    "compiler-version": ["error", "0.6.12"],
     "no-empty-blocks": "off",
     "not-rely-on-time": "off",
     "avoid-low-level-calls": "off",

CONTRIBUTING.md

@@ -54,7 +54,7 @@ We use [prettier](https://prettier.io/) for formatting both Solidity and TypeScr
 
 ### Solidity
 
-Please adhere to the recommended [official Solidity style guide for v0.6.8](https://solidity.readthedocs.io/en/v0.6.8/style-guide.html), in addition to the following styling choices:
+Please adhere to the recommended [official Solidity style guide for v0.6.12](https://solidity.readthedocs.io/en/v0.6.12/style-guide.html), in addition to the following styling choices:
 
 #### State variables
 

contracts/mocks/MockVaultLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../persistent/vault/VaultLibBaseCore.sol";
 

contracts/mocks/WETH.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 contract WETH {
     string public name = "Wrapped Ether";

contracts/mocks/adapters/MockGenericAdapter.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import "../../release/extensions/integration-manager/integrations/utils/AdapterBase.sol";

contracts/mocks/integratees/MockCTokenIntegratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20Burnable.sol";
 import "../prices/CentralizedRateProvider.sol";

contracts/mocks/integratees/MockChaiIntegratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../tokens/MockToken.sol";
 import "../prices/CentralizedRateProvider.sol";

contracts/mocks/integratees/MockGenericIntegratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../utils/SwapperBase.sol";
 

contracts/mocks/integratees/MockKyberIntegratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/access/Ownable.sol";
 import "@openzeppelin/contracts/math/SafeMath.sol";

contracts/mocks/integratees/MockParaSwapIntegratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
 import "@openzeppelin/contracts/math/SafeMath.sol";

contracts/mocks/integratees/MockSynthetixIntegratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/access/Ownable.sol";
 import "./../../release/interfaces/ISynthetixExchangeRates.sol";

contracts/mocks/integratees/MockUniswapV2Integratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/access/Ownable.sol";
 import "@openzeppelin/contracts/math/SafeMath.sol";

contracts/mocks/integratees/MockZeroExV2Integratee.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 contract MockZeroExV2Integratee {
     bytes public ZRX_ASSET_DATA;

contracts/mocks/integratees/utils/MockIntegrateeBase.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../../utils/NormalizedRateProviderBase.sol";
 import "../../utils/SwapperBase.sol";

contracts/mocks/integratees/utils/SimpleMockIntegrateeBase.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "./MockIntegrateeBase.sol";
 

contracts/mocks/interfaces/ISynthetixDelegateApprovals.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title ISynthetixDelegateApprovals Interface
 /// @author Melon Council DAO <[email protected]>

contracts/mocks/prices/CentralizedRateProvider.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/math/SafeMath.sol";
 import "@openzeppelin/contracts/access/Ownable.sol";

contracts/mocks/prices/MockChaiPriceSource.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/math/SafeMath.sol";
 

contracts/mocks/prices/MockChainlinkPriceSource.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 contract MockChainlinkPriceSource {
     event AnswerUpdated(int256 indexed current, uint256 indexed roundId, uint256 timestamp);

contracts/mocks/prices/MockDerivativePriceFeed.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../../release/infrastructure/price-feeds/derivatives/IDerivativePriceFeed.sol";
 

contracts/mocks/prices/MockKyberPriceSource.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../utils/NormalizedRateProviderBase.sol";
 

contracts/mocks/prices/MockPrimitivePriceFeed.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 import "../../release/infrastructure/price-feeds/primitives/IPrimitivePriceFeed.sol";
 
 contract MockPrimitivePriceFeed is IPrimitivePriceFeed {

contracts/mocks/prices/MockSynthetixPriceSource.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
 import "@openzeppelin/contracts/access/Ownable.sol";

contracts/mocks/prices/MockUniswapV2PriceSource.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import "@openzeppelin/contracts/math/SafeMath.sol";

contracts/mocks/tokens/MockReentrancyToken.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../../release/core/fund/comptroller/ComptrollerLib.sol";
 import "./MockToken.sol";

contracts/mocks/tokens/MockSynthetixToken.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/access/Ownable.sol";
 import "@openzeppelin/contracts/math/SafeMath.sol";

contracts/mocks/tokens/MockToken.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20Burnable.sol";
 import "@openzeppelin/contracts/math/SafeMath.sol";

contracts/mocks/utils/EthConstantMixin.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 abstract contract EthConstantMixin {
     address public constant ETH_ADDRESS = 0xEeeeeEeeeEeEeeEeEeEeeEEEeeeeEeeeeeeeEEeE;

contracts/mocks/utils/NormalizedRateProviderBase.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/math/SafeMath.sol";
 import "./RateProviderBase.sol";

contracts/mocks/utils/RateProviderBase.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import "./EthConstantMixin.sol";

contracts/mocks/utils/SwapperBase.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import "./EthConstantMixin.sol";

contracts/persistent/dispatcher/Dispatcher.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../utils/IMigrationHookHandler.sol";
 import "../utils/IMigratableVault.sol";

contracts/persistent/dispatcher/IDispatcher.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title IDispatcher Interface
 /// @author Melon Council DAO <[email protected]>

contracts/persistent/utils/IMigratableVault.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title IMigratableVault Interface
 /// @author Melon Council DAO <[email protected]>

contracts/persistent/utils/IMigrationHookHandler.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title IMigrationHookHandler Interface
 /// @author Melon Council DAO <[email protected]>

contracts/persistent/vault/VaultLibBase1.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "./VaultLibBaseCore.sol";
 

contracts/persistent/vault/VaultLibBaseCore.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../utils/IMigratableVault.sol";
 import "./utils/ProxiableVaultLib.sol";

contracts/persistent/vault/VaultProxy.sol

@@ -1,12 +1,12 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "./utils/ProxiableVaultLib.sol";
 
 /// @title VaultProxy Contract
 /// @author Melon Council DAO <[email protected]>
 /// @notice A proxy contract for all VaultProxy instances, slightly modified from EIP-1822
-/// @dev Adapted from the recommended implementation of a Proxy in EIP-1822, updated for solc 0.6.8,
+/// @dev Adapted from the recommended implementation of a Proxy in EIP-1822, updated for solc 0.6.12,
 /// and using the EIP-1967 storage slot for the proxiable implementation.
 /// i.e., `bytes32(uint256(keccak256('eip1967.proxy.implementation')) - 1)`, which is
 /// "0x360894a13ba1a3210667c828492db98dca3e2076cc3735a920a3ca505d382bbc"

contracts/persistent/vault/utils/ProxiableVaultLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title ProxiableVaultLib Contract
 /// @author Melon Council DAO <[email protected]>

contracts/persistent/vault/utils/SharesTokenBase.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "./VaultLibSafeMath.sol";
 

contracts/persistent/vault/utils/VaultLibSafeMath.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title VaultLibSafeMath library
 /// @notice A narrowed, verbatim implementation of OpenZeppelin 3.2.0 SafeMath

contracts/release/core/fund-deployer/FundDeployer.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 pragma experimental ABIEncoderV2;
 
 import "../../../persistent/dispatcher/IDispatcher.sol";
@@ -420,7 +420,7 @@ contract FundDeployer is IFundDeployer, IMigrationHookHandler {
             "postMigrateOriginHook: Only Dispatcher can call this function"
         );
 
-        /// Must use PreMigrate hook to get the ComptrollerProxy from the VaultProxy
+        // Must use PreMigrate hook to get the ComptrollerProxy from the VaultProxy
         address comptrollerProxy = IVault(_vaultProxy).getAccessor();
 
         // Wind down fund and destroy its config

contracts/release/core/fund-deployer/IFundDeployer.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title IFundDeployer Interface
 /// @author Melon Council DAO <[email protected]>

contracts/release/core/fund/comptroller/ComptrollerLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/math/SafeMath.sol";
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contracts/release/core/fund/comptroller/ComptrollerProxy.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../../../utils/Proxy.sol";
 

contracts/release/core/fund/comptroller/IComptroller.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "./libs/IPermissionedVaultActionLib.sol";
 

contracts/release/core/fund/comptroller/libs/FundLifecycleLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import "../../../../extensions/IExtension.sol";

contracts/release/core/fund/comptroller/libs/IFundLifecycleLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../../vault/IVault.sol";
 

contracts/release/core/fund/comptroller/libs/IPermissionedVaultActionLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title IPermissionedVaultActionLib Interface
 /// @author Melon Council DAO <[email protected]>

contracts/release/core/fund/comptroller/libs/PermissionedVaultActionLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../../../fund-deployer/IFundDeployer.sol";
 import "../../vault/IVault.sol";

contracts/release/core/fund/comptroller/utils/ComptrollerEvents.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title ComptrollerEvents Contract
 /// @author Melon Council DAO <[email protected]>

contracts/release/core/fund/comptroller/utils/ComptrollerStorage.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 /// @title ComptrollerStorage Contract
 /// @author Melon Council DAO <[email protected]>

contracts/release/core/fund/vault/IVault.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "../../../../persistent/utils/IMigratableVault.sol";
 

contracts/release/core/fund/vault/VaultLib.sol

@@ -1,5 +1,5 @@
 // SPDX-License-Identifier: GPL-3.0
-pragma solidity 0.6.8;
+pragma solidity 0.6.12;
 
 import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
 import "@openzeppelin/contracts/token/ERC20/SafeERC20.sol";