Compiler version to recommended 0.6.11

Author: Brandon Iles

contracts/Forth.sol

@@ -1,4 +1,6 @@
-pragma solidity ^0.5.16;
+// SPDX-License-Identifier: BSD-3-Clause
+
+pragma solidity 0.6.11;
 pragma experimental ABIEncoderV2;
 
 import "./SafeMath.sol";
@@ -28,10 +30,10 @@ contract Forth {
     /// @notice Cap on the percentage of totalSupply that can be minted at each mint
     uint8 public constant mintCap = 2;
 
-    /// @notice Allowance amounts on behalf of others
+    /// @dev Allowance amounts on behalf of others
     mapping (address => mapping (address => uint96)) internal allowances;
 
-    /// @notice Official record of token balances for each account
+    /// @dev Official record of token balances for each account
     mapping (address => uint96) internal balances;
 
     /// @notice A record of each accounts delegate

contracts/GovernorAlpha.sol

@@ -1,4 +1,6 @@
-pragma solidity ^0.5.16;
+// SPDX-License-Identifier: BSD-3-Clause
+
+pragma solidity 0.6.11;
 pragma experimental ABIEncoderV2;
 
 contract GovernorAlpha {
@@ -30,58 +32,58 @@ contract GovernorAlpha {
     uint public proposalCount;
 
     struct Proposal {
-        /// @notice Unique id for looking up a proposal
+        // Unique id for looking up a proposal
         uint id;
 
-        /// @notice Creator of the proposal
+        // Creator of the proposal
         address proposer;
 
-        /// @notice The timestamp that the proposal will be available for execution, set once the vote succeeds
+        // The timestamp that the proposal will be available for execution, set once the vote succeeds
         uint eta;
 
-        /// @notice the ordered list of target addresses for calls to be made
+        // The ordered list of target addresses for calls to be made
         address[] targets;
 
-        /// @notice The ordered list of values (i.e. msg.value) to be passed to the calls to be made
+        // The ordered list of values (i.e. msg.value) to be passed to the calls to be made
         uint[] values;
 
-        /// @notice The ordered list of function signatures to be called
+        // The ordered list of function signatures to be called
         string[] signatures;
 
-        /// @notice The ordered list of calldata to be passed to each call
+        // The ordered list of calldata to be passed to each call
         bytes[] calldatas;
 
-        /// @notice The block at which voting begins: holders must delegate their votes prior to this block
+        // The block at which voting begins: holders must delegate their votes prior to this block
         uint startBlock;
 
-        /// @notice The block at which voting ends: votes must be cast prior to this block
+        // The block at which voting ends: votes must be cast prior to this block
         uint endBlock;
 
-        /// @notice Current number of votes in favor of this proposal
+        // Current number of votes in favor of this proposal
         uint forVotes;
 
-        /// @notice Current number of votes in opposition to this proposal
+        // Current number of votes in opposition to this proposal
         uint againstVotes;
 
-        /// @notice Flag marking whether the proposal has been canceled
+        // Flag marking whether the proposal has been canceled
         bool canceled;
 
-        /// @notice Flag marking whether the proposal has been executed
+        // Flag marking whether the proposal has been executed
         bool executed;
 
-        /// @notice Receipts of ballots for the entire set of voters
+        // Receipts of ballots for the entire set of voters
         mapping (address => Receipt) receipts;
     }
 
     /// @notice Ballot receipt record for a voter
     struct Receipt {
-        /// @notice Whether or not a vote has been cast
+        // Whether or not a vote has been cast
         bool hasVoted;
 
-        /// @notice Whether or not the voter supports the proposal
+        // Whether or not the voter supports the proposal
         bool support;
 
-        /// @notice The number of votes the voter had, which were cast
+        // The number of votes the voter had, which were cast
         uint96 votes;
     }
 
@@ -190,7 +192,7 @@ contract GovernorAlpha {
         Proposal storage proposal = proposals[proposalId];
         proposal.executed = true;
         for (uint i = 0; i < proposal.targets.length; i++) {
-            timelock.executeTransaction.value(proposal.values[i])(proposal.targets[i], proposal.values[i], proposal.signatures[i], proposal.calldatas[i], proposal.eta);
+            timelock.executeTransaction{value: proposal.values[i]}(proposal.targets[i], proposal.values[i], proposal.signatures[i], proposal.calldatas[i], proposal.eta);
         }
         emit ProposalExecuted(proposalId);
     }

contracts/SafeMath.sol

@@ -1,4 +1,6 @@
-pragma solidity ^0.5.16;
+// SPDX-License-Identifier: MIT
+
+pragma solidity 0.6.11;
 
 // From https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/math/Math.sol
 // Subject to the MIT license.
@@ -183,4 +185,4 @@ library SafeMath {
         require(b != 0, errorMessage);
         return a % b;
     }
-}
+}

contracts/Timelock.sol

@@ -1,4 +1,6 @@
-pragma solidity ^0.5.16;
+// SPDX-License-Identifier: BSD-3-Clause
+
+pragma solidity ^0.6.11;
 
 import "./SafeMath.sol";
 
@@ -31,7 +33,7 @@ contract Timelock {
         delay = delay_;
     }
 
-    function() external payable { }
+    receive() external payable { }
 
     function setDelay(uint delay_) public {
         require(msg.sender == address(this), "Timelock::setDelay: Call must come from Timelock.");
@@ -96,7 +98,7 @@ contract Timelock {
         }
 
         // solium-disable-next-line security/no-call-value
-        (bool success, bytes memory returnData) = target.call.value(value)(callData);
+        (bool success, bytes memory returnData) = target.call{value: value}(callData);
         require(success, "Timelock::executeTransaction: Transaction execution reverted.");
 
         emit ExecuteTransaction(txHash, target, value, signature, data, eta);
@@ -108,4 +110,4 @@ contract Timelock {
         // solium-disable-next-line security/no-block-members
         return block.timestamp;
     }
-}
+}

package.json

@@ -24,7 +24,7 @@
     "mocha": "^8.1.3",
     "prettier": "^2.1.1",
     "rimraf": "^3.0.2",
-    "solc": "0.5.16",
+    "solc": "0.6.11",
     "ts-node": "^9.0.0",
     "typescript": "^4.0.2"
   }

yarn.lock

@@ -6641,10 +6641,10 @@ snapdragon@^0.8.1:
     source-map-resolve "^0.5.0"
     use "^3.1.0"
 
-solc@0.5.16:
-  version "0.5.16"
-  resolved "https://registry.yarnpkg.com/solc/-/solc-0.5.16.tgz#6c8d710a3792ccc79db924606b558a1149b1c603"
-  integrity sha512-weEtRtisJyf+8UjELs7S4ST1KK7UIq6SRB7tpprfJBL9b5mTrZAT7m4gJKi2h6MiBpuSWfnraK8BnkyWzuTMRA==
+solc@0.6.11:
+  version "0.6.11"
+  resolved "https://registry.yarnpkg.com/solc/-/solc-0.6.11.tgz#3205b13c8162a02c5d8f1d85ff267889a5095467"
+  integrity sha512-qMe8epy45eMzXZ9IGDk986NGjakC5/s+yPGuO99YsDaJQitxDAd3rIItlzxgfEvjr0xNJ3IaqGAGvvJ0/59nfA==
   dependencies:
     command-exists "^1.2.8"
     commander "3.0.2"