From 62894b1de5fb5709cac920de1d470ed42d738cc2 Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 8 Apr 2023 15:52:25 -0300
Subject: [PATCH 01/13] mid commit

---
 .../GovernorVotesQuorumFraction.sol           |  11 +-
 contracts/governance/utils/Votes.sol          |  14 +-
 .../token/ERC20/extensions/ERC20Votes.sol     |   2 +-
 contracts/utils/Checkpoints.sol               | 196 ------------------
 package.json                                  |   2 +-
 scripts/generate/templates/Checkpoints.js     |   4 -
 6 files changed, 16 insertions(+), 213 deletions(-)

diff --git a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
index 8efefce3959..80c189f30fb 100644
--- a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
+++ b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
@@ -14,10 +14,10 @@ import "../../utils/math/SafeCast.sol";
  * _Available since v4.3._
  */
 abstract contract GovernorVotesQuorumFraction is GovernorVotes {
-    using Checkpoints for Checkpoints.History;
+    using Checkpoints for Checkpoints.Trace224;
 
     uint256 private _quorumNumerator; // DEPRECATED
-    Checkpoints.History private _quorumNumeratorHistory;
+    Checkpoints.Trace224 private _quorumNumeratorHistory;
 
     event QuorumNumeratorUpdated(uint256 oldQuorumNumerator, uint256 newQuorumNumerator);
 
@@ -50,13 +50,14 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
         }
 
         // Optimistic search, check the latest checkpoint
-        Checkpoints.Checkpoint memory latest = _quorumNumeratorHistory._checkpoints[length - 1];
-        if (latest._blockNumber <= blockNumber) {
+        Checkpoints.Checkpoint224 memory latest = _quorumNumeratorHistory._checkpoints[length - 1];
+        if (latest._key <= blockNumber) {
             return latest._value;
         }
 
         // Otherwise, do the binary search
-        return _quorumNumeratorHistory.getAtBlock(blockNumber);
+        uint32 key = SafeCast.toUint32(blockNumber); 
+        return _quorumNumeratorHistory.lowerLookup(key);
     }
 
     /**
diff --git a/contracts/governance/utils/Votes.sol b/contracts/governance/utils/Votes.sol
index ccac72bce2a..dd81762c402 100644
--- a/contracts/governance/utils/Votes.sol
+++ b/contracts/governance/utils/Votes.sol
@@ -30,14 +30,14 @@ import "../../utils/math/SafeCast.sol";
  * _Available since v4.5._
  */
 abstract contract Votes is IVotes, Context, EIP712, Nonces {
-    using Checkpoints for Checkpoints.History;
+    using Checkpoints for Checkpoints.Trace224;
 
     bytes32 private constant _DELEGATION_TYPEHASH =
         keccak256("Delegation(address delegatee,uint256 nonce,uint256 expiry)");
 
     mapping(address => address) private _delegation;
-    mapping(address => Checkpoints.History) private _delegateCheckpoints;
-    Checkpoints.History private _totalCheckpoints;
+    mapping(address => Checkpoints.Trace224) private _delegateCheckpoints;
+    Checkpoints.Trace224 private _totalCheckpoints;
 
     /**
      * @dev Returns the current amount of votes that `account` has.
@@ -54,7 +54,8 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
      * - `blockNumber` must have been already mined
      */
     function getPastVotes(address account, uint256 blockNumber) public view virtual override returns (uint256) {
-        return _delegateCheckpoints[account].getAtProbablyRecentBlock(blockNumber);
+        uint32 key = SafeCast.toUint32(blockNumber);
+        return _delegateCheckpoints[account].upperLookup(key);
     }
 
     /**
@@ -69,7 +70,8 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
      * - `blockNumber` must have been already mined
      */
     function getPastTotalSupply(uint256 blockNumber) public view virtual override returns (uint256) {
-        return _totalCheckpoints.getAtProbablyRecentBlock(blockNumber);
+        uint32 key = SafeCast.toUint32(blockNumber);
+        return _totalCheckpoints.upperLookup(key);
     }
 
     /**
@@ -169,7 +171,7 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
     /**
      * @dev Get the `pos`-th checkpoint for `account`.
      */
-    function _checkpoints(address account, uint32 pos) internal view virtual returns (Checkpoints.Checkpoint memory) {
+    function _checkpoints(address account, uint32 pos) internal view virtual returns (Checkpoints.Checkpoint224 memory) {
         return _delegateCheckpoints[account].getAtPosition(pos);
     }
 
diff --git a/contracts/token/ERC20/extensions/ERC20Votes.sol b/contracts/token/ERC20/extensions/ERC20Votes.sol
index 225d08c443e..fe25b9bb506 100644
--- a/contracts/token/ERC20/extensions/ERC20Votes.sol
+++ b/contracts/token/ERC20/extensions/ERC20Votes.sol
@@ -53,7 +53,7 @@ abstract contract ERC20Votes is ERC20, Votes {
     /**
      * @dev Get the `pos`-th checkpoint for `account`.
      */
-    function checkpoints(address account, uint32 pos) public view virtual returns (Checkpoints.Checkpoint memory) {
+    function checkpoints(address account, uint32 pos) public view virtual returns (Checkpoints.Checkpoint224 memory) {
         return _checkpoints(account, pos);
     }
 
diff --git a/contracts/utils/Checkpoints.sol b/contracts/utils/Checkpoints.sol
index 76203edd2ce..ada1bbedcb7 100644
--- a/contracts/utils/Checkpoints.sol
+++ b/contracts/utils/Checkpoints.sol
@@ -17,202 +17,6 @@ import "./math/SafeCast.sol";
  * _Available since v4.5._
  */
 library Checkpoints {
-    struct History {
-        Checkpoint[] _checkpoints;
-    }
-
-    struct Checkpoint {
-        uint32 _blockNumber;
-        uint224 _value;
-    }
-
-    /**
-     * @dev Returns the value at a given block number. If a checkpoint is not available at that block, the closest one
-     * before it is returned, or zero otherwise. Because the number returned corresponds to that at the end of the
-     * block, the requested block number must be in the past, excluding the current block.
-     */
-    function getAtBlock(History storage self, uint256 blockNumber) internal view returns (uint256) {
-        require(blockNumber < block.number, "Checkpoints: block not yet mined");
-        uint32 key = SafeCast.toUint32(blockNumber);
-
-        uint256 len = self._checkpoints.length;
-        uint256 pos = _upperBinaryLookup(self._checkpoints, key, 0, len);
-        return pos == 0 ? 0 : _unsafeAccess(self._checkpoints, pos - 1)._value;
-    }
-
-    /**
-     * @dev Returns the value at a given block number. If a checkpoint is not available at that block, the closest one
-     * before it is returned, or zero otherwise. Similar to {upperLookup} but optimized for the case when the searched
-     * checkpoint is probably "recent", defined as being among the last sqrt(N) checkpoints where N is the number of
-     * checkpoints.
-     */
-    function getAtProbablyRecentBlock(History storage self, uint256 blockNumber) internal view returns (uint256) {
-        require(blockNumber < block.number, "Checkpoints: block not yet mined");
-        uint32 key = SafeCast.toUint32(blockNumber);
-
-        uint256 len = self._checkpoints.length;
-
-        uint256 low = 0;
-        uint256 high = len;
-
-        if (len > 5) {
-            uint256 mid = len - Math.sqrt(len);
-            if (key < _unsafeAccess(self._checkpoints, mid)._blockNumber) {
-                high = mid;
-            } else {
-                low = mid + 1;
-            }
-        }
-
-        uint256 pos = _upperBinaryLookup(self._checkpoints, key, low, high);
-
-        return pos == 0 ? 0 : _unsafeAccess(self._checkpoints, pos - 1)._value;
-    }
-
-    /**
-     * @dev Returns checkpoint at given position.
-     */
-    function getAtPosition(History storage self, uint32 pos) internal view returns (Checkpoint memory) {
-        return self._checkpoints[pos];
-    }
-
-    /**
-     * @dev Pushes a value onto a History so that it is stored as the checkpoint for the current block.
-     *
-     * Returns previous value and new value.
-     */
-    function push(History storage self, uint256 value) internal returns (uint256, uint256) {
-        return _insert(self._checkpoints, SafeCast.toUint32(block.number), SafeCast.toUint224(value));
-    }
-
-    /**
-     * @dev Pushes a value onto a History, by updating the latest value using binary operation `op`. The new value will
-     * be set to `op(latest, delta)`.
-     *
-     * Returns previous value and new value.
-     */
-    function push(
-        History storage self,
-        function(uint256, uint256) view returns (uint256) op,
-        uint256 delta
-    ) internal returns (uint256, uint256) {
-        return push(self, op(latest(self), delta));
-    }
-
-    /**
-     * @dev Returns the value in the most recent checkpoint, or zero if there are no checkpoints.
-     */
-    function latest(History storage self) internal view returns (uint224) {
-        uint256 pos = self._checkpoints.length;
-        return pos == 0 ? 0 : _unsafeAccess(self._checkpoints, pos - 1)._value;
-    }
-
-    /**
-     * @dev Returns whether there is a checkpoint in the structure (i.e. it is not empty), and if so the key and value
-     * in the most recent checkpoint.
-     */
-    function latestCheckpoint(
-        History storage self
-    ) internal view returns (bool exists, uint32 _blockNumber, uint224 _value) {
-        uint256 pos = self._checkpoints.length;
-        if (pos == 0) {
-            return (false, 0, 0);
-        } else {
-            Checkpoint memory ckpt = _unsafeAccess(self._checkpoints, pos - 1);
-            return (true, ckpt._blockNumber, ckpt._value);
-        }
-    }
-
-    /**
-     * @dev Returns the number of checkpoint.
-     */
-    function length(History storage self) internal view returns (uint256) {
-        return self._checkpoints.length;
-    }
-
-    /**
-     * @dev Pushes a (`key`, `value`) pair into an ordered list of checkpoints, either by inserting a new checkpoint,
-     * or by updating the last one.
-     */
-    function _insert(Checkpoint[] storage self, uint32 key, uint224 value) private returns (uint224, uint224) {
-        uint256 pos = self.length;
-
-        if (pos > 0) {
-            // Copying to memory is important here.
-            Checkpoint memory last = _unsafeAccess(self, pos - 1);
-
-            // Checkpoint keys must be non-decreasing.
-            require(last._blockNumber <= key, "Checkpoint: decreasing keys");
-
-            // Update or push new checkpoint
-            if (last._blockNumber == key) {
-                _unsafeAccess(self, pos - 1)._value = value;
-            } else {
-                self.push(Checkpoint({_blockNumber: key, _value: value}));
-            }
-            return (last._value, value);
-        } else {
-            self.push(Checkpoint({_blockNumber: key, _value: value}));
-            return (0, value);
-        }
-    }
-
-    /**
-     * @dev Return the index of the oldest checkpoint whose key is greater than the search key, or `high` if there is none.
-     * `low` and `high` define a section where to do the search, with inclusive `low` and exclusive `high`.
-     *
-     * WARNING: `high` should not be greater than the array's length.
-     */
-    function _upperBinaryLookup(
-        Checkpoint[] storage self,
-        uint32 key,
-        uint256 low,
-        uint256 high
-    ) private view returns (uint256) {
-        while (low < high) {
-            uint256 mid = Math.average(low, high);
-            if (_unsafeAccess(self, mid)._blockNumber > key) {
-                high = mid;
-            } else {
-                low = mid + 1;
-            }
-        }
-        return high;
-    }
-
-    /**
-     * @dev Return the index of the oldest checkpoint whose key is greater or equal than the search key, or `high` if there is none.
-     * `low` and `high` define a section where to do the search, with inclusive `low` and exclusive `high`.
-     *
-     * WARNING: `high` should not be greater than the array's length.
-     */
-    function _lowerBinaryLookup(
-        Checkpoint[] storage self,
-        uint32 key,
-        uint256 low,
-        uint256 high
-    ) private view returns (uint256) {
-        while (low < high) {
-            uint256 mid = Math.average(low, high);
-            if (_unsafeAccess(self, mid)._blockNumber < key) {
-                low = mid + 1;
-            } else {
-                high = mid;
-            }
-        }
-        return high;
-    }
-
-    /**
-     * @dev Access an element of the array without performing bounds check. The position is assumed to be within bounds.
-     */
-    function _unsafeAccess(Checkpoint[] storage self, uint256 pos) private pure returns (Checkpoint storage result) {
-        assembly {
-            mstore(0, self.slot)
-            result.slot := add(keccak256(0, 0x20), pos)
-        }
-    }
-
     struct Trace224 {
         Checkpoint224[] _checkpoints;
     }
diff --git a/package.json b/package.json
index 72978ffec05..5b0eb34fe95 100644
--- a/package.json
+++ b/package.json
@@ -22,7 +22,7 @@
     "clean": "hardhat clean && rimraf build contracts/build",
     "prepare": "scripts/prepare.sh",
     "prepack": "scripts/prepack.sh",
-    "generate": "scripts/generate/run.js",
+    "generate": "node scripts/generate/run.js",
     "release": "scripts/release/release.sh",
     "version": "scripts/release/version.sh",
     "test": "hardhat test",
diff --git a/scripts/generate/templates/Checkpoints.js b/scripts/generate/templates/Checkpoints.js
index c4673d245f9..99f7aaa92c3 100644
--- a/scripts/generate/templates/Checkpoints.js
+++ b/scripts/generate/templates/Checkpoints.js
@@ -295,10 +295,6 @@ module.exports = format(
   header.trimEnd(),
   'library Checkpoints {',
   [
-    // Legacy types & functions
-    types(LEGACY_OPTS),
-    legacyOperations(LEGACY_OPTS),
-    common(LEGACY_OPTS),
     // New flavors
     ...OPTS.flatMap(opts => [types(opts), operations(opts), common(opts)]),
   ],

From 3b8610f90457d877e96a6ce31d53de88aa1b8bee Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 8 Apr 2023 16:35:30 -0300
Subject: [PATCH 02/13] proposal 1

---
 .../GovernorVotesQuorumFraction.sol           |  4 +-
 contracts/utils/Checkpoints.sol               | 32 ++++++++++
 scripts/generate/templates/Checkpoints.js     | 59 +++----------------
 3 files changed, 41 insertions(+), 54 deletions(-)

diff --git a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
index 80c189f30fb..d84ef60319b 100644
--- a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
+++ b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
@@ -108,12 +108,12 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
         // Make sure we keep track of the original numerator in contracts upgraded from a version without checkpoints.
         if (oldQuorumNumerator != 0 && _quorumNumeratorHistory._checkpoints.length == 0) {
             _quorumNumeratorHistory._checkpoints.push(
-                Checkpoints.Checkpoint({_blockNumber: 0, _value: SafeCast.toUint224(oldQuorumNumerator)})
+                Checkpoints.Checkpoint224({_key: 0, _value: SafeCast.toUint224(oldQuorumNumerator)})
             );
         }
 
         // Set new quorum for future proposals
-        _quorumNumeratorHistory.push(newQuorumNumerator);
+        _quorumNumeratorHistory.push(SafeCast.toUint224(newQuorumNumerator));
 
         emit QuorumNumeratorUpdated(oldQuorumNumerator, newQuorumNumerator);
     }
diff --git a/contracts/utils/Checkpoints.sol b/contracts/utils/Checkpoints.sol
index ada1bbedcb7..fdc27504eed 100644
--- a/contracts/utils/Checkpoints.sol
+++ b/contracts/utils/Checkpoints.sol
@@ -17,6 +17,38 @@ import "./math/SafeCast.sol";
  * _Available since v4.5._
  */
 library Checkpoints {
+    /**
+     * @dev Returns checkpoint at given position.
+     */
+    function getAtPosition(Trace224 storage self, uint32 pos) internal view returns (Checkpoint224 memory) {
+        return self._checkpoints[pos];
+    }
+
+    /**
+     * @dev Pushes a value onto a History so that it is stored as the checkpoint for the current block.
+     *
+     * Returns previous value and new value.
+     */
+    function push(Trace224 storage self, uint256 value) internal returns (uint256, uint256) {
+        return _insert(self._checkpoints, SafeCast.toUint32(block.number), SafeCast.toUint224(value));
+    }
+
+    /**
+     * @dev Pushes a value onto a History, by updating the latest value using binary operation `op`. The new value will
+     * be set to `op(latest, delta)`.
+     *
+     * Returns previous value and new value.
+     */
+    function push(
+        Trace224 storage self,
+        function(uint256, uint256) view returns (uint256) op,
+        uint256 delta
+    ) internal returns (uint256, uint256) {
+        uint32 key = SafeCast.toUint32(block.number);
+        uint224 value = SafeCast.toUint224(op(latest(self), delta));
+        return push(self, key, value);
+    }
+
     struct Trace224 {
         Checkpoint224[] _checkpoints;
     }
diff --git a/scripts/generate/templates/Checkpoints.js b/scripts/generate/templates/Checkpoints.js
index 99f7aaa92c3..79b2f354421 100644
--- a/scripts/generate/templates/Checkpoints.js
+++ b/scripts/generate/templates/Checkpoints.js
@@ -65,53 +65,10 @@ function upperLookup(${opts.historyTypeName} storage self, ${opts.keyTypeName} k
 `;
 
 const legacyOperations = opts => `\
-/**
- * @dev Returns the value at a given block number. If a checkpoint is not available at that block, the closest one
- * before it is returned, or zero otherwise. Because the number returned corresponds to that at the end of the
- * block, the requested block number must be in the past, excluding the current block.
- */
-function getAtBlock(${opts.historyTypeName} storage self, uint256 blockNumber) internal view returns (uint256) {
-    require(blockNumber < block.number, "Checkpoints: block not yet mined");
-    uint32 key = SafeCast.toUint32(blockNumber);
-
-    uint256 len = self.${opts.checkpointFieldName}.length;
-    uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, 0, len);
-    return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
-}
-
-/**
- * @dev Returns the value at a given block number. If a checkpoint is not available at that block, the closest one
- * before it is returned, or zero otherwise. Similar to {upperLookup} but optimized for the case when the searched
- * checkpoint is probably "recent", defined as being among the last sqrt(N) checkpoints where N is the number of
- * checkpoints.
- */
-function getAtProbablyRecentBlock(${opts.historyTypeName} storage self, uint256 blockNumber) internal view returns (uint256) {
-    require(blockNumber < block.number, "Checkpoints: block not yet mined");
-    uint32 key = SafeCast.toUint32(blockNumber);
-
-    uint256 len = self.${opts.checkpointFieldName}.length;
-
-    uint256 low = 0;
-    uint256 high = len;
-
-    if (len > 5) {
-        uint256 mid = len - Math.sqrt(len);
-        if (key < _unsafeAccess(self.${opts.checkpointFieldName}, mid)._blockNumber) {
-            high = mid;
-        } else {
-            low = mid + 1;
-        }
-    }
-
-    uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, low, high);
-
-    return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
-}
-
 /**
  * @dev Returns checkpoint at given position.
  */
-function getAtPosition(History storage self, uint32 pos) internal view returns (Checkpoint memory) {
+function getAtPosition(${opts.historyTypeName} storage self, uint32 pos) internal view returns (${opts.checkpointTypeName} memory) {
     return self._checkpoints[pos];
 }
 
@@ -135,7 +92,9 @@ function push(
     function(uint256, uint256) view returns (uint256) op,
     uint256 delta
 ) internal returns (uint256, uint256) {
-    return push(self, op(latest(self), delta));
+    uint32 key = SafeCast.toUint32(block.number);
+    ${opts.valueTypeName} value = SafeCast.to${opts.valueTypeNameCap}(op(latest(self), delta));
+    return push(self, key, value);
 }
 `;
 
@@ -278,23 +237,19 @@ const defaultOpts = size => ({
   keyTypeName: `uint${256 - size}`,
   keyFieldName: '_key',
   valueTypeName: `uint${size}`,
+  valueTypeNameCap: `Uint${size}`,
   valueFieldName: '_value',
 });
 
 const OPTS = VALUE_SIZES.map(size => defaultOpts(size));
 
-const LEGACY_OPTS = {
-  ...defaultOpts(224),
-  historyTypeName: 'History',
-  checkpointTypeName: 'Checkpoint',
-  keyFieldName: '_blockNumber',
-};
-
 // GENERATE
 module.exports = format(
   header.trimEnd(),
   'library Checkpoints {',
   [
+    // Legacy function
+    legacyOperations(defaultOpts(224)),
     // New flavors
     ...OPTS.flatMap(opts => [types(opts), operations(opts), common(opts)]),
   ],

From 578bc8bf72ff5007462945269a707f1e06cf7231 Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 15 Apr 2023 10:58:30 -0300
Subject: [PATCH 03/13] Checkpoint tests some fixes

---
 test/utils/Checkpoints.test.js | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/test/utils/Checkpoints.test.js b/test/utils/Checkpoints.test.js
index d43d469cc17..013a690b139 100644
--- a/test/utils/Checkpoints.test.js
+++ b/test/utils/Checkpoints.test.js
@@ -14,14 +14,14 @@ contract('Checkpoints', function () {
     this.mock = await $Checkpoints.new();
   });
 
-  describe('History checkpoints', function () {
-    const latest = (self, ...args) => self.methods['$latest_Checkpoints_History(uint256)'](0, ...args);
+  describe.only('History checkpoints', function () {
+    const latest = (self, ...args) => self.methods['$latest_Checkpoints_Trace224(uint256)'](0, ...args);
     const latestCheckpoint = (self, ...args) =>
-      self.methods['$latestCheckpoint_Checkpoints_History(uint256)'](0, ...args);
+      self.methods['$latestCheckpoint_Checkpoints_Trace224(uint256)'](0, ...args);
     const push = (self, ...args) => self.methods['$push(uint256,uint256)'](0, ...args);
     const getAtBlock = (self, ...args) => self.methods['$getAtBlock(uint256,uint256)'](0, ...args);
     const getAtRecentBlock = (self, ...args) => self.methods['$getAtProbablyRecentBlock(uint256,uint256)'](0, ...args);
-    const getLength = (self, ...args) => self.methods['$length_Checkpoints_History(uint256)'](0, ...args);
+    const getLength = (self, ...args) => self.methods['$length_Checkpoints_Trace224(uint256)'](0, ...args);
 
     describe('without checkpoints', function () {
       it('returns zero as latest value', async function () {

From d53e29d1e519db342f9585113ea12c6b3bfd9dfa Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 15 Apr 2023 15:10:04 -0300
Subject: [PATCH 04/13] returns zero as past value

---
 test/utils/Checkpoints.test.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/test/utils/Checkpoints.test.js b/test/utils/Checkpoints.test.js
index 013a690b139..634dd8f9a0e 100644
--- a/test/utils/Checkpoints.test.js
+++ b/test/utils/Checkpoints.test.js
@@ -19,7 +19,7 @@ contract('Checkpoints', function () {
     const latestCheckpoint = (self, ...args) =>
       self.methods['$latestCheckpoint_Checkpoints_Trace224(uint256)'](0, ...args);
     const push = (self, ...args) => self.methods['$push(uint256,uint256)'](0, ...args);
-    const getAtBlock = (self, ...args) => self.methods['$getAtBlock(uint256,uint256)'](0, ...args);
+    const getAtBlock = (self, ...args) => self.methods['$upperLookup(uint256,uint32)'](0, ...args);
     const getAtRecentBlock = (self, ...args) => self.methods['$getAtProbablyRecentBlock(uint256,uint256)'](0, ...args);
     const getLength = (self, ...args) => self.methods['$length_Checkpoints_Trace224(uint256)'](0, ...args);
 
@@ -36,7 +36,6 @@ contract('Checkpoints', function () {
       it('returns zero as past value', async function () {
         await time.advanceBlock();
         expect(await getAtBlock(this.mock, (await web3.eth.getBlockNumber()) - 1)).to.be.bignumber.equal('0');
-        expect(await getAtRecentBlock(this.mock, (await web3.eth.getBlockNumber()) - 1)).to.be.bignumber.equal('0');
       });
     });
 

From d89cf696e9e29b847a2625f8d7248878ef8daa40 Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 15 Apr 2023 15:17:07 -0300
Subject: [PATCH 05/13] more tests

---
 test/utils/Checkpoints.test.js | 46 ++++++++--------------------------
 1 file changed, 10 insertions(+), 36 deletions(-)

diff --git a/test/utils/Checkpoints.test.js b/test/utils/Checkpoints.test.js
index 634dd8f9a0e..97bf079bd3c 100644
--- a/test/utils/Checkpoints.test.js
+++ b/test/utils/Checkpoints.test.js
@@ -20,7 +20,6 @@ contract('Checkpoints', function () {
       self.methods['$latestCheckpoint_Checkpoints_Trace224(uint256)'](0, ...args);
     const push = (self, ...args) => self.methods['$push(uint256,uint256)'](0, ...args);
     const getAtBlock = (self, ...args) => self.methods['$upperLookup(uint256,uint32)'](0, ...args);
-    const getAtRecentBlock = (self, ...args) => self.methods['$getAtProbablyRecentBlock(uint256,uint256)'](0, ...args);
     const getLength = (self, ...args) => self.methods['$length_Checkpoints_Trace224(uint256)'](0, ...args);
 
     describe('without checkpoints', function () {
@@ -58,30 +57,17 @@ contract('Checkpoints', function () {
         expect(ckpt[2]).to.be.bignumber.equal(web3.utils.toBN('3'));
       });
 
-      for (const getAtBlockVariant of [getAtBlock, getAtRecentBlock]) {
-        describe(`lookup: ${getAtBlockVariant}`, function () {
-          it('returns past values', async function () {
-            expect(await getAtBlockVariant(this.mock, this.tx1.receipt.blockNumber - 1)).to.be.bignumber.equal('0');
-            expect(await getAtBlockVariant(this.mock, this.tx1.receipt.blockNumber)).to.be.bignumber.equal('1');
-            expect(await getAtBlockVariant(this.mock, this.tx2.receipt.blockNumber)).to.be.bignumber.equal('2');
-            // Block with no new checkpoints
-            expect(await getAtBlockVariant(this.mock, this.tx2.receipt.blockNumber + 1)).to.be.bignumber.equal('2');
-            expect(await getAtBlockVariant(this.mock, this.tx3.receipt.blockNumber)).to.be.bignumber.equal('3');
-            expect(await getAtBlockVariant(this.mock, this.tx3.receipt.blockNumber + 1)).to.be.bignumber.equal('3');
-          });
-          it('reverts if block number >= current block', async function () {
-            await expectRevert(
-              getAtBlockVariant(this.mock, await web3.eth.getBlockNumber()),
-              'Checkpoints: block not yet mined',
-            );
-
-            await expectRevert(
-              getAtBlockVariant(this.mock, (await web3.eth.getBlockNumber()) + 1),
-              'Checkpoints: block not yet mined',
-            );
-          });
+      describe(`lookup: getAtBlock`, function () {
+        it('returns past values', async function () {
+          expect(await getAtBlock(this.mock, this.tx1.receipt.blockNumber - 1)).to.be.bignumber.equal('0');
+          expect(await getAtBlock(this.mock, this.tx1.receipt.blockNumber)).to.be.bignumber.equal('1');
+          expect(await getAtBlock(this.mock, this.tx2.receipt.blockNumber)).to.be.bignumber.equal('2');
+          // Block with no new checkpoints
+          expect(await getAtBlock(this.mock, this.tx2.receipt.blockNumber + 1)).to.be.bignumber.equal('2');
+          expect(await getAtBlock(this.mock, this.tx3.receipt.blockNumber)).to.be.bignumber.equal('3');
+          expect(await getAtBlock(this.mock, this.tx3.receipt.blockNumber + 1)).to.be.bignumber.equal('3');
         });
-      }
+      });
 
       it('multiple checkpoints in the same block', async function () {
         const lengthBefore = await getLength(this.mock);
@@ -95,18 +81,6 @@ contract('Checkpoints', function () {
         expect(await getLength(this.mock)).to.be.bignumber.equal(lengthBefore.addn(1));
         expect(await latest(this.mock)).to.be.bignumber.equal('10');
       });
-
-      it('more than 5 checkpoints', async function () {
-        for (let i = 4; i <= 6; i++) {
-          await push(this.mock, i);
-        }
-        expect(await getLength(this.mock)).to.be.bignumber.equal('6');
-        const block = await web3.eth.getBlockNumber();
-        // recent
-        expect(await getAtRecentBlock(this.mock, block - 1)).to.be.bignumber.equal('5');
-        // non-recent
-        expect(await getAtRecentBlock(this.mock, block - 9)).to.be.bignumber.equal('0');
-      });
     });
   });
 

From 83f4f643427bc42908c6dad273972a5b38c8a82b Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 15 Apr 2023 15:35:08 -0300
Subject: [PATCH 06/13] Votes

---
 contracts/governance/utils/Votes.sol    | 2 ++
 test/governance/utils/Votes.behavior.js | 2 +-
 test/governance/utils/Votes.test.js     | 4 ++--
 test/utils/Checkpoints.test.js          | 2 +-
 4 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/contracts/governance/utils/Votes.sol b/contracts/governance/utils/Votes.sol
index dd81762c402..e6ca8c19dce 100644
--- a/contracts/governance/utils/Votes.sol
+++ b/contracts/governance/utils/Votes.sol
@@ -54,6 +54,7 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
      * - `blockNumber` must have been already mined
      */
     function getPastVotes(address account, uint256 blockNumber) public view virtual override returns (uint256) {
+        require(blockNumber < block.number, 'Votes: block not yet mined');
         uint32 key = SafeCast.toUint32(blockNumber);
         return _delegateCheckpoints[account].upperLookup(key);
     }
@@ -70,6 +71,7 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
      * - `blockNumber` must have been already mined
      */
     function getPastTotalSupply(uint256 blockNumber) public view virtual override returns (uint256) {
+        require(blockNumber < block.number, 'Votes: block not yet mined');
         uint32 key = SafeCast.toUint32(blockNumber);
         return _totalCheckpoints.upperLookup(key);
     }
diff --git a/test/governance/utils/Votes.behavior.js b/test/governance/utils/Votes.behavior.js
index 7cc8f133eb9..70de6e540d2 100644
--- a/test/governance/utils/Votes.behavior.js
+++ b/test/governance/utils/Votes.behavior.js
@@ -281,7 +281,7 @@ function shouldBehaveLikeVotes(accounts, tokens, fungible = true) {
         expect(await this.votes.getPastTotalSupply(blockNumber + 9)).to.be.bignumber.equal(weight[2]);
         expect(await this.votes.getPastTotalSupply(blockNumber + 10)).to.be.bignumber.equal(weight[2]);
         expect(await this.votes.getPastTotalSupply(blockNumber + 11)).to.be.bignumber.equal('0');
-        await expectRevert(this.votes.getPastTotalSupply(blockNumber + 12), 'Checkpoints: block not yet mined');
+        await expectRevert(this.votes.getPastTotalSupply(blockNumber + 12), 'Votes: block not yet mined');
       });
     });
 
diff --git a/test/governance/utils/Votes.test.js b/test/governance/utils/Votes.test.js
index c0c574df4e0..06e3eb2b24c 100644
--- a/test/governance/utils/Votes.test.js
+++ b/test/governance/utils/Votes.test.js
@@ -37,7 +37,7 @@ contract('Votes', function (accounts) {
     it('reverts if block number >= current block', async function () {
       await expectRevert(
         this.votes.getPastTotalSupply(this.txs.at(-1).receipt.blockNumber + 1),
-        'Checkpoints: block not yet mined',
+        'Votes: block not yet mined',
       );
     });
 
@@ -76,7 +76,7 @@ contract('Votes', function (accounts) {
     });
   });
 
-  describe('performs voting workflow', function () {
+  describe.only('performs voting workflow', function () {
     beforeEach(async function () {
       this.chainId = await getChainId();
     });
diff --git a/test/utils/Checkpoints.test.js b/test/utils/Checkpoints.test.js
index 97bf079bd3c..9d35e85f5b4 100644
--- a/test/utils/Checkpoints.test.js
+++ b/test/utils/Checkpoints.test.js
@@ -14,7 +14,7 @@ contract('Checkpoints', function () {
     this.mock = await $Checkpoints.new();
   });
 
-  describe.only('History checkpoints', function () {
+  describe('History checkpoints', function () {
     const latest = (self, ...args) => self.methods['$latest_Checkpoints_Trace224(uint256)'](0, ...args);
     const latestCheckpoint = (self, ...args) =>
       self.methods['$latestCheckpoint_Checkpoints_Trace224(uint256)'](0, ...args);

From bf2282842b63fb8196c49e5569fb10c946d294dd Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 15 Apr 2023 16:01:24 -0300
Subject: [PATCH 07/13] ERC20Votes

---
 test/governance/utils/Votes.test.js            | 2 +-
 test/token/ERC20/extensions/ERC20Votes.test.js | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/test/governance/utils/Votes.test.js b/test/governance/utils/Votes.test.js
index 06e3eb2b24c..e27a8ccf1c0 100644
--- a/test/governance/utils/Votes.test.js
+++ b/test/governance/utils/Votes.test.js
@@ -76,7 +76,7 @@ contract('Votes', function (accounts) {
     });
   });
 
-  describe.only('performs voting workflow', function () {
+  describe('performs voting workflow', function () {
     beforeEach(async function () {
       this.chainId = await getChainId();
     });
diff --git a/test/token/ERC20/extensions/ERC20Votes.test.js b/test/token/ERC20/extensions/ERC20Votes.test.js
index 8d010ec6bc9..d3e237283ab 100644
--- a/test/token/ERC20/extensions/ERC20Votes.test.js
+++ b/test/token/ERC20/extensions/ERC20Votes.test.js
@@ -422,7 +422,7 @@ contract('ERC20Votes', function (accounts) {
 
     describe('getPastVotes', function () {
       it('reverts if block number >= current block', async function () {
-        await expectRevert(this.token.getPastVotes(other1, 5e10), 'Checkpoints: block not yet mined');
+        await expectRevert(this.token.getPastVotes(other1, 5e10), 'Votes: block not yet mined');
       });
 
       it('returns 0 if there are no checkpoints', async function () {
@@ -503,7 +503,7 @@ contract('ERC20Votes', function (accounts) {
     });
 
     it('reverts if block number >= current block', async function () {
-      await expectRevert(this.token.getPastTotalSupply(5e10), 'Checkpoints: block not yet mined');
+      await expectRevert(this.token.getPastTotalSupply(5e10), 'Votes: block not yet mined');
     });
 
     it('returns 0 if there are no checkpoints', async function () {

From 9b13eb313b5a8d6b74e995b1078cc3c8b334aee4 Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 15 Apr 2023 16:12:33 -0300
Subject: [PATCH 08/13] ERC20VotesComp

---
 test/token/ERC20/extensions/ERC20VotesComp.test.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/test/token/ERC20/extensions/ERC20VotesComp.test.js b/test/token/ERC20/extensions/ERC20VotesComp.test.js
index ef4a22be225..c7ef1cad19a 100644
--- a/test/token/ERC20/extensions/ERC20VotesComp.test.js
+++ b/test/token/ERC20/extensions/ERC20VotesComp.test.js
@@ -389,7 +389,7 @@ contract('ERC20VotesComp', function (accounts) {
 
     describe('getPriorVotes', function () {
       it('reverts if block number >= current block', async function () {
-        await expectRevert(this.token.getPriorVotes(other1, 5e10), 'Checkpoints: block not yet mined');
+        await expectRevert(this.token.getPriorVotes(other1, 5e10), 'Votes: block not yet mined');
       });
 
       it('returns 0 if there are no checkpoints', async function () {
@@ -470,7 +470,7 @@ contract('ERC20VotesComp', function (accounts) {
     });
 
     it('reverts if block number >= current block', async function () {
-      await expectRevert(this.token.getPastTotalSupply(5e10), 'Checkpoints: block not yet mined');
+      await expectRevert(this.token.getPastTotalSupply(5e10), 'Votes: block not yet mined');
     });
 
     it('returns 0 if there are no checkpoints', async function () {

From a91837cb63e2cabff2c002587e550d0b21ea67aa Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sat, 15 Apr 2023 16:47:41 -0300
Subject: [PATCH 09/13] Tested

---
 contracts/governance/extensions/GovernorVotesQuorumFraction.sol | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
index d84ef60319b..f41b73dd710 100644
--- a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
+++ b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
@@ -57,7 +57,7 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
 
         // Otherwise, do the binary search
         uint32 key = SafeCast.toUint32(blockNumber); 
-        return _quorumNumeratorHistory.lowerLookup(key);
+        return _quorumNumeratorHistory.upperLookup(key);
     }
 
     /**

From 73ce43726ac08465af5a08a515d1406e0d043603 Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sun, 16 Apr 2023 09:37:02 -0300
Subject: [PATCH 10/13] compiled

---
 .../GovernorVotesQuorumFraction.sol           |  9 +++---
 contracts/governance/utils/Votes.sol          | 31 +++++++++++-------
 .../token/ERC20/extensions/ERC20Votes.sol     |  7 ----
 contracts/utils/Checkpoints.sol               | 32 -------------------
 scripts/generate/templates/Checkpoints.js     |  2 --
 5 files changed, 25 insertions(+), 56 deletions(-)

diff --git a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
index f41b73dd710..6c57f2d395e 100644
--- a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
+++ b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
@@ -107,13 +107,14 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
 
         // Make sure we keep track of the original numerator in contracts upgraded from a version without checkpoints.
         if (oldQuorumNumerator != 0 && _quorumNumeratorHistory._checkpoints.length == 0) {
-            _quorumNumeratorHistory._checkpoints.push(
-                Checkpoints.Checkpoint224({_key: 0, _value: SafeCast.toUint224(oldQuorumNumerator)})
-            );
+            _quorumNumeratorHistory.push(0, SafeCast.toUint224(oldQuorumNumerator));
         }
 
         // Set new quorum for future proposals
-        _quorumNumeratorHistory.push(SafeCast.toUint224(newQuorumNumerator));
+        _quorumNumeratorHistory.push(
+            SafeCast.toUint32(block.number), 
+            SafeCast.toUint224(newQuorumNumerator)
+        );
 
         emit QuorumNumeratorUpdated(oldQuorumNumerator, newQuorumNumerator);
     }
diff --git a/contracts/governance/utils/Votes.sol b/contracts/governance/utils/Votes.sol
index e6ca8c19dce..8ecba74495a 100644
--- a/contracts/governance/utils/Votes.sol
+++ b/contracts/governance/utils/Votes.sol
@@ -139,10 +139,18 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
      */
     function _transferVotingUnits(address from, address to, uint256 amount) internal virtual {
         if (from == address(0)) {
-            _totalCheckpoints.push(_add, amount);
+            uint224 latest = _totalCheckpoints.latest();
+            _totalCheckpoints.push(
+                SafeCast.toUint32(block.timestamp), 
+                latest + SafeCast.toUint32(amount)
+            );
         }
         if (to == address(0)) {
-            _totalCheckpoints.push(_subtract, amount);
+            uint224 latest = _totalCheckpoints.latest();
+            _totalCheckpoints.push(
+                SafeCast.toUint32(block.timestamp), 
+                latest - SafeCast.toUint32(amount)
+            );
         }
         _moveDelegateVotes(delegates(from), delegates(to), amount);
     }
@@ -153,11 +161,19 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
     function _moveDelegateVotes(address from, address to, uint256 amount) private {
         if (from != to && amount > 0) {
             if (from != address(0)) {
-                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[from].push(_subtract, amount);
+                uint224 latest = _totalCheckpoints.latest();
+                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[from].push(
+                    SafeCast.toUint32(block.timestamp), 
+                    latest - SafeCast.toUint32(amount)
+                );
                 emit DelegateVotesChanged(from, oldValue, newValue);
             }
             if (to != address(0)) {
-                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[to].push(_add, amount);
+                uint224 latest = _totalCheckpoints.latest();
+                (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[to].push(
+                    SafeCast.toUint32(block.timestamp), 
+                    latest + SafeCast.toUint32(amount)
+                );
                 emit DelegateVotesChanged(to, oldValue, newValue);
             }
         }
@@ -170,13 +186,6 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
         return SafeCast.toUint32(_delegateCheckpoints[account].length());
     }
 
-    /**
-     * @dev Get the `pos`-th checkpoint for `account`.
-     */
-    function _checkpoints(address account, uint32 pos) internal view virtual returns (Checkpoints.Checkpoint224 memory) {
-        return _delegateCheckpoints[account].getAtPosition(pos);
-    }
-
     function _add(uint256 a, uint256 b) private pure returns (uint256) {
         return a + b;
     }
diff --git a/contracts/token/ERC20/extensions/ERC20Votes.sol b/contracts/token/ERC20/extensions/ERC20Votes.sol
index fe25b9bb506..a2b52a16359 100644
--- a/contracts/token/ERC20/extensions/ERC20Votes.sol
+++ b/contracts/token/ERC20/extensions/ERC20Votes.sol
@@ -50,13 +50,6 @@ abstract contract ERC20Votes is ERC20, Votes {
         return _numCheckpoints(account);
     }
 
-    /**
-     * @dev Get the `pos`-th checkpoint for `account`.
-     */
-    function checkpoints(address account, uint32 pos) public view virtual returns (Checkpoints.Checkpoint224 memory) {
-        return _checkpoints(account, pos);
-    }
-
     /**
      * @dev Returns the balance of `account`.
      */
diff --git a/contracts/utils/Checkpoints.sol b/contracts/utils/Checkpoints.sol
index fdc27504eed..ada1bbedcb7 100644
--- a/contracts/utils/Checkpoints.sol
+++ b/contracts/utils/Checkpoints.sol
@@ -17,38 +17,6 @@ import "./math/SafeCast.sol";
  * _Available since v4.5._
  */
 library Checkpoints {
-    /**
-     * @dev Returns checkpoint at given position.
-     */
-    function getAtPosition(Trace224 storage self, uint32 pos) internal view returns (Checkpoint224 memory) {
-        return self._checkpoints[pos];
-    }
-
-    /**
-     * @dev Pushes a value onto a History so that it is stored as the checkpoint for the current block.
-     *
-     * Returns previous value and new value.
-     */
-    function push(Trace224 storage self, uint256 value) internal returns (uint256, uint256) {
-        return _insert(self._checkpoints, SafeCast.toUint32(block.number), SafeCast.toUint224(value));
-    }
-
-    /**
-     * @dev Pushes a value onto a History, by updating the latest value using binary operation `op`. The new value will
-     * be set to `op(latest, delta)`.
-     *
-     * Returns previous value and new value.
-     */
-    function push(
-        Trace224 storage self,
-        function(uint256, uint256) view returns (uint256) op,
-        uint256 delta
-    ) internal returns (uint256, uint256) {
-        uint32 key = SafeCast.toUint32(block.number);
-        uint224 value = SafeCast.toUint224(op(latest(self), delta));
-        return push(self, key, value);
-    }
-
     struct Trace224 {
         Checkpoint224[] _checkpoints;
     }
diff --git a/scripts/generate/templates/Checkpoints.js b/scripts/generate/templates/Checkpoints.js
index 79b2f354421..bbee1f2c00d 100644
--- a/scripts/generate/templates/Checkpoints.js
+++ b/scripts/generate/templates/Checkpoints.js
@@ -248,8 +248,6 @@ module.exports = format(
   header.trimEnd(),
   'library Checkpoints {',
   [
-    // Legacy function
-    legacyOperations(defaultOpts(224)),
     // New flavors
     ...OPTS.flatMap(opts => [types(opts), operations(opts), common(opts)]),
   ],

From 8b9029b31d183a0c72d991db00024f97059c858b Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Sun, 16 Apr 2023 09:42:57 -0300
Subject: [PATCH 11/13] lint

---
 .../GovernorVotesQuorumFraction.sol           |  7 +---
 contracts/governance/utils/Votes.sol          | 18 +++------
 scripts/generate/templates/Checkpoints.js     | 38 +------------------
 3 files changed, 9 insertions(+), 54 deletions(-)

diff --git a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
index 6c57f2d395e..0c4aea4e083 100644
--- a/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
+++ b/contracts/governance/extensions/GovernorVotesQuorumFraction.sol
@@ -56,7 +56,7 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
         }
 
         // Otherwise, do the binary search
-        uint32 key = SafeCast.toUint32(blockNumber); 
+        uint32 key = SafeCast.toUint32(blockNumber);
         return _quorumNumeratorHistory.upperLookup(key);
     }
 
@@ -111,10 +111,7 @@ abstract contract GovernorVotesQuorumFraction is GovernorVotes {
         }
 
         // Set new quorum for future proposals
-        _quorumNumeratorHistory.push(
-            SafeCast.toUint32(block.number), 
-            SafeCast.toUint224(newQuorumNumerator)
-        );
+        _quorumNumeratorHistory.push(SafeCast.toUint32(block.number), SafeCast.toUint224(newQuorumNumerator));
 
         emit QuorumNumeratorUpdated(oldQuorumNumerator, newQuorumNumerator);
     }
diff --git a/contracts/governance/utils/Votes.sol b/contracts/governance/utils/Votes.sol
index 8ecba74495a..c4b3bd4059f 100644
--- a/contracts/governance/utils/Votes.sol
+++ b/contracts/governance/utils/Votes.sol
@@ -54,7 +54,7 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
      * - `blockNumber` must have been already mined
      */
     function getPastVotes(address account, uint256 blockNumber) public view virtual override returns (uint256) {
-        require(blockNumber < block.number, 'Votes: block not yet mined');
+        require(blockNumber < block.number, "Votes: block not yet mined");
         uint32 key = SafeCast.toUint32(blockNumber);
         return _delegateCheckpoints[account].upperLookup(key);
     }
@@ -71,7 +71,7 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
      * - `blockNumber` must have been already mined
      */
     function getPastTotalSupply(uint256 blockNumber) public view virtual override returns (uint256) {
-        require(blockNumber < block.number, 'Votes: block not yet mined');
+        require(blockNumber < block.number, "Votes: block not yet mined");
         uint32 key = SafeCast.toUint32(blockNumber);
         return _totalCheckpoints.upperLookup(key);
     }
@@ -140,17 +140,11 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
     function _transferVotingUnits(address from, address to, uint256 amount) internal virtual {
         if (from == address(0)) {
             uint224 latest = _totalCheckpoints.latest();
-            _totalCheckpoints.push(
-                SafeCast.toUint32(block.timestamp), 
-                latest + SafeCast.toUint32(amount)
-            );
+            _totalCheckpoints.push(SafeCast.toUint32(block.timestamp), latest + SafeCast.toUint32(amount));
         }
         if (to == address(0)) {
             uint224 latest = _totalCheckpoints.latest();
-            _totalCheckpoints.push(
-                SafeCast.toUint32(block.timestamp), 
-                latest - SafeCast.toUint32(amount)
-            );
+            _totalCheckpoints.push(SafeCast.toUint32(block.timestamp), latest - SafeCast.toUint32(amount));
         }
         _moveDelegateVotes(delegates(from), delegates(to), amount);
     }
@@ -163,7 +157,7 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
             if (from != address(0)) {
                 uint224 latest = _totalCheckpoints.latest();
                 (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[from].push(
-                    SafeCast.toUint32(block.timestamp), 
+                    SafeCast.toUint32(block.timestamp),
                     latest - SafeCast.toUint32(amount)
                 );
                 emit DelegateVotesChanged(from, oldValue, newValue);
@@ -171,7 +165,7 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
             if (to != address(0)) {
                 uint224 latest = _totalCheckpoints.latest();
                 (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[to].push(
-                    SafeCast.toUint32(block.timestamp), 
+                    SafeCast.toUint32(block.timestamp),
                     latest + SafeCast.toUint32(amount)
                 );
                 emit DelegateVotesChanged(to, oldValue, newValue);
diff --git a/scripts/generate/templates/Checkpoints.js b/scripts/generate/templates/Checkpoints.js
index bbee1f2c00d..bb65b653a5f 100644
--- a/scripts/generate/templates/Checkpoints.js
+++ b/scripts/generate/templates/Checkpoints.js
@@ -62,43 +62,7 @@ function upperLookup(${opts.historyTypeName} storage self, ${opts.keyTypeName} k
     uint256 pos = _upperBinaryLookup(self.${opts.checkpointFieldName}, key, 0, len);
     return pos == 0 ? 0 : _unsafeAccess(self.${opts.checkpointFieldName}, pos - 1).${opts.valueFieldName};
 }
-`;
-
-const legacyOperations = opts => `\
-/**
- * @dev Returns checkpoint at given position.
- */
-function getAtPosition(${opts.historyTypeName} storage self, uint32 pos) internal view returns (${opts.checkpointTypeName} memory) {
-    return self._checkpoints[pos];
-}
-
-/**
- * @dev Pushes a value onto a History so that it is stored as the checkpoint for the current block.
- *
- * Returns previous value and new value.
- */
-function push(${opts.historyTypeName} storage self, uint256 value) internal returns (uint256, uint256) {
-    return _insert(self.${opts.checkpointFieldName}, SafeCast.toUint32(block.number), SafeCast.toUint224(value));
-}
-
-/**
- * @dev Pushes a value onto a History, by updating the latest value using binary operation \`op\`. The new value will
- * be set to \`op(latest, delta)\`.
- *
- * Returns previous value and new value.
- */
-function push(
-    ${opts.historyTypeName} storage self,
-    function(uint256, uint256) view returns (uint256) op,
-    uint256 delta
-) internal returns (uint256, uint256) {
-    uint32 key = SafeCast.toUint32(block.number);
-    ${opts.valueTypeName} value = SafeCast.to${opts.valueTypeNameCap}(op(latest(self), delta));
-    return push(self, key, value);
-}
-`;
 
-const common = opts => `\
 /**
  * @dev Returns the value in the most recent checkpoint, or zero if there are no checkpoints.
  */
@@ -249,7 +213,7 @@ module.exports = format(
   'library Checkpoints {',
   [
     // New flavors
-    ...OPTS.flatMap(opts => [types(opts), operations(opts), common(opts)]),
+    ...OPTS.flatMap(opts => [types(opts), operations(opts)]),
   ],
   '}',
 );

From 16ae23b7fd5013b47f15f717735c89138752b580 Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Mon, 17 Apr 2023 01:48:57 -0300
Subject: [PATCH 12/13] some fixes

---
 contracts/governance/utils/Votes.sol          | 23 ++++--
 .../token/ERC20/extensions/ERC20Votes.sol     |  7 ++
 .../token/ERC20/extensions/ERC20Votes.test.js | 12 +--
 test/utils/Checkpoints.test.js                | 74 +------------------
 4 files changed, 29 insertions(+), 87 deletions(-)

diff --git a/contracts/governance/utils/Votes.sol b/contracts/governance/utils/Votes.sol
index c4b3bd4059f..a6657b361eb 100644
--- a/contracts/governance/utils/Votes.sol
+++ b/contracts/governance/utils/Votes.sol
@@ -140,11 +140,11 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
     function _transferVotingUnits(address from, address to, uint256 amount) internal virtual {
         if (from == address(0)) {
             uint224 latest = _totalCheckpoints.latest();
-            _totalCheckpoints.push(SafeCast.toUint32(block.timestamp), latest + SafeCast.toUint32(amount));
+            _totalCheckpoints.push(SafeCast.toUint32(block.number), latest + SafeCast.toUint224(amount));
         }
         if (to == address(0)) {
             uint224 latest = _totalCheckpoints.latest();
-            _totalCheckpoints.push(SafeCast.toUint32(block.timestamp), latest - SafeCast.toUint32(amount));
+            _totalCheckpoints.push(SafeCast.toUint32(block.number), latest - SafeCast.toUint224(amount));
         }
         _moveDelegateVotes(delegates(from), delegates(to), amount);
     }
@@ -155,18 +155,18 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
     function _moveDelegateVotes(address from, address to, uint256 amount) private {
         if (from != to && amount > 0) {
             if (from != address(0)) {
-                uint224 latest = _totalCheckpoints.latest();
+                uint224 latest = _delegateCheckpoints[from].latest();
                 (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[from].push(
-                    SafeCast.toUint32(block.timestamp),
-                    latest - SafeCast.toUint32(amount)
+                    SafeCast.toUint32(block.number),
+                    latest - SafeCast.toUint224(amount)
                 );
                 emit DelegateVotesChanged(from, oldValue, newValue);
             }
             if (to != address(0)) {
-                uint224 latest = _totalCheckpoints.latest();
+                uint224 latest = _delegateCheckpoints[to].latest();
                 (uint256 oldValue, uint256 newValue) = _delegateCheckpoints[to].push(
-                    SafeCast.toUint32(block.timestamp),
-                    latest + SafeCast.toUint32(amount)
+                    SafeCast.toUint32(block.number),
+                    latest + SafeCast.toUint224(amount)
                 );
                 emit DelegateVotesChanged(to, oldValue, newValue);
             }
@@ -180,6 +180,13 @@ abstract contract Votes is IVotes, Context, EIP712, Nonces {
         return SafeCast.toUint32(_delegateCheckpoints[account].length());
     }
 
+    /**
+     * @dev Get the `pos`-th checkpoint for `account`.
+     */
+    function _checkpoints(address account, uint32 pos) internal view virtual returns (Checkpoints.Checkpoint224 memory) {
+        return _delegateCheckpoints[account]._checkpoints[pos];
+    }
+
     function _add(uint256 a, uint256 b) private pure returns (uint256) {
         return a + b;
     }
diff --git a/contracts/token/ERC20/extensions/ERC20Votes.sol b/contracts/token/ERC20/extensions/ERC20Votes.sol
index a2b52a16359..fe25b9bb506 100644
--- a/contracts/token/ERC20/extensions/ERC20Votes.sol
+++ b/contracts/token/ERC20/extensions/ERC20Votes.sol
@@ -50,6 +50,13 @@ abstract contract ERC20Votes is ERC20, Votes {
         return _numCheckpoints(account);
     }
 
+    /**
+     * @dev Get the `pos`-th checkpoint for `account`.
+     */
+    function checkpoints(address account, uint32 pos) public view virtual returns (Checkpoints.Checkpoint224 memory) {
+        return _checkpoints(account, pos);
+    }
+
     /**
      * @dev Returns the balance of `account`.
      */
diff --git a/test/token/ERC20/extensions/ERC20Votes.test.js b/test/token/ERC20/extensions/ERC20Votes.test.js
index d3e237283ab..dd0619109e9 100644
--- a/test/token/ERC20/extensions/ERC20Votes.test.js
+++ b/test/token/ERC20/extensions/ERC20Votes.test.js
@@ -61,7 +61,7 @@ contract('ERC20Votes', function (accounts) {
     expect(await this.token.getPastVotes(holder, block - 6)).to.be.bignumber.equal('0');
   });
 
-  describe('set delegation', function () {
+  describe.only('set delegation', function () {
     describe('call', function () {
       it('delegation with balance', async function () {
         await this.token.$_mint(holder, supply);
@@ -231,7 +231,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe('change delegation', function () {
+  describe.only('change delegation', function () {
     beforeEach(async function () {
       await this.token.$_mint(holder, supply);
       await this.token.delegate(holder, { from: holder });
@@ -269,7 +269,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe('transfers', function () {
+  describe.only('transfers', function () {
     beforeEach(async function () {
       await this.token.$_mint(holder, supply);
     });
@@ -360,7 +360,7 @@ contract('ERC20Votes', function (accounts) {
   });
 
   // The following tests are a adaptation of https://github.com/compound-finance/compound-protocol/blob/master/tests/Governance/CompTest.js.
-  describe('Compound test suite', function () {
+  describe.only('Compound test suite', function () {
     beforeEach(async function () {
       await this.token.$_mint(holder, supply);
     });
@@ -497,7 +497,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe('getPastTotalSupply', function () {
+  describe.only('getPastTotalSupply', function () {
     beforeEach(async function () {
       await this.token.delegate(holder, { from: holder });
     });
@@ -574,7 +574,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe('Voting workflow', function () {
+  describe.only('Voting workflow', function () {
     beforeEach(async function () {
       this.name = name;
       this.votes = this.token;
diff --git a/test/utils/Checkpoints.test.js b/test/utils/Checkpoints.test.js
index 9d35e85f5b4..47b5153410d 100644
--- a/test/utils/Checkpoints.test.js
+++ b/test/utils/Checkpoints.test.js
@@ -1,9 +1,7 @@
-const { expectRevert, time } = require('@openzeppelin/test-helpers');
+const { expectRevert } = require('@openzeppelin/test-helpers');
 
 const { expect } = require('chai');
 
-const { batchInBlock } = require('../helpers/txpool');
-
 const $Checkpoints = artifacts.require('$Checkpoints');
 
 const first = array => (array.length ? array[0] : undefined);
@@ -14,76 +12,6 @@ contract('Checkpoints', function () {
     this.mock = await $Checkpoints.new();
   });
 
-  describe('History checkpoints', function () {
-    const latest = (self, ...args) => self.methods['$latest_Checkpoints_Trace224(uint256)'](0, ...args);
-    const latestCheckpoint = (self, ...args) =>
-      self.methods['$latestCheckpoint_Checkpoints_Trace224(uint256)'](0, ...args);
-    const push = (self, ...args) => self.methods['$push(uint256,uint256)'](0, ...args);
-    const getAtBlock = (self, ...args) => self.methods['$upperLookup(uint256,uint32)'](0, ...args);
-    const getLength = (self, ...args) => self.methods['$length_Checkpoints_Trace224(uint256)'](0, ...args);
-
-    describe('without checkpoints', function () {
-      it('returns zero as latest value', async function () {
-        expect(await latest(this.mock)).to.be.bignumber.equal('0');
-
-        const ckpt = await latestCheckpoint(this.mock);
-        expect(ckpt[0]).to.be.equal(false);
-        expect(ckpt[1]).to.be.bignumber.equal('0');
-        expect(ckpt[2]).to.be.bignumber.equal('0');
-      });
-
-      it('returns zero as past value', async function () {
-        await time.advanceBlock();
-        expect(await getAtBlock(this.mock, (await web3.eth.getBlockNumber()) - 1)).to.be.bignumber.equal('0');
-      });
-    });
-
-    describe('with checkpoints', function () {
-      beforeEach('pushing checkpoints', async function () {
-        this.tx1 = await push(this.mock, 1);
-        this.tx2 = await push(this.mock, 2);
-        await time.advanceBlock();
-        this.tx3 = await push(this.mock, 3);
-        await time.advanceBlock();
-        await time.advanceBlock();
-      });
-
-      it('returns latest value', async function () {
-        expect(await latest(this.mock)).to.be.bignumber.equal('3');
-
-        const ckpt = await latestCheckpoint(this.mock);
-        expect(ckpt[0]).to.be.equal(true);
-        expect(ckpt[1]).to.be.bignumber.equal(web3.utils.toBN(this.tx3.receipt.blockNumber));
-        expect(ckpt[2]).to.be.bignumber.equal(web3.utils.toBN('3'));
-      });
-
-      describe(`lookup: getAtBlock`, function () {
-        it('returns past values', async function () {
-          expect(await getAtBlock(this.mock, this.tx1.receipt.blockNumber - 1)).to.be.bignumber.equal('0');
-          expect(await getAtBlock(this.mock, this.tx1.receipt.blockNumber)).to.be.bignumber.equal('1');
-          expect(await getAtBlock(this.mock, this.tx2.receipt.blockNumber)).to.be.bignumber.equal('2');
-          // Block with no new checkpoints
-          expect(await getAtBlock(this.mock, this.tx2.receipt.blockNumber + 1)).to.be.bignumber.equal('2');
-          expect(await getAtBlock(this.mock, this.tx3.receipt.blockNumber)).to.be.bignumber.equal('3');
-          expect(await getAtBlock(this.mock, this.tx3.receipt.blockNumber + 1)).to.be.bignumber.equal('3');
-        });
-      });
-
-      it('multiple checkpoints in the same block', async function () {
-        const lengthBefore = await getLength(this.mock);
-
-        await batchInBlock([
-          () => push(this.mock, 8, { gas: 100000 }),
-          () => push(this.mock, 9, { gas: 100000 }),
-          () => push(this.mock, 10, { gas: 100000 }),
-        ]);
-
-        expect(await getLength(this.mock)).to.be.bignumber.equal(lengthBefore.addn(1));
-        expect(await latest(this.mock)).to.be.bignumber.equal('10');
-      });
-    });
-  });
-
   for (const length of [160, 224]) {
     describe(`Trace${length}`, function () {
       const latest = (self, ...args) => self.methods[`$latest_Checkpoints_Trace${length}(uint256)`](0, ...args);

From da3ac5394243f97dccfd4a5db9b6457a0a40e16c Mon Sep 17 00:00:00 2001
From: RenanSouza2 <renan.rodrigues.souza1@gmail.com>
Date: Mon, 17 Apr 2023 01:57:57 -0300
Subject: [PATCH 13/13] enable tests

---
 test/token/ERC20/extensions/ERC20Votes.test.js | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/test/token/ERC20/extensions/ERC20Votes.test.js b/test/token/ERC20/extensions/ERC20Votes.test.js
index dd0619109e9..d3e237283ab 100644
--- a/test/token/ERC20/extensions/ERC20Votes.test.js
+++ b/test/token/ERC20/extensions/ERC20Votes.test.js
@@ -61,7 +61,7 @@ contract('ERC20Votes', function (accounts) {
     expect(await this.token.getPastVotes(holder, block - 6)).to.be.bignumber.equal('0');
   });
 
-  describe.only('set delegation', function () {
+  describe('set delegation', function () {
     describe('call', function () {
       it('delegation with balance', async function () {
         await this.token.$_mint(holder, supply);
@@ -231,7 +231,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe.only('change delegation', function () {
+  describe('change delegation', function () {
     beforeEach(async function () {
       await this.token.$_mint(holder, supply);
       await this.token.delegate(holder, { from: holder });
@@ -269,7 +269,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe.only('transfers', function () {
+  describe('transfers', function () {
     beforeEach(async function () {
       await this.token.$_mint(holder, supply);
     });
@@ -360,7 +360,7 @@ contract('ERC20Votes', function (accounts) {
   });
 
   // The following tests are a adaptation of https://github.com/compound-finance/compound-protocol/blob/master/tests/Governance/CompTest.js.
-  describe.only('Compound test suite', function () {
+  describe('Compound test suite', function () {
     beforeEach(async function () {
       await this.token.$_mint(holder, supply);
     });
@@ -497,7 +497,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe.only('getPastTotalSupply', function () {
+  describe('getPastTotalSupply', function () {
     beforeEach(async function () {
       await this.token.delegate(holder, { from: holder });
     });
@@ -574,7 +574,7 @@ contract('ERC20Votes', function (accounts) {
     });
   });
 
-  describe.only('Voting workflow', function () {
+  describe('Voting workflow', function () {
     beforeEach(async function () {
       this.name = name;
       this.votes = this.token;