Merge pull request #8843 from ethereum/deprecate-now

[BREAKING] Deprecate keyword now

Changelog.md

@@ -3,6 +3,7 @@
 Breaking changes:
  * Type Checker: Disallow virtual for library functions.
  * Deprecated dot syntax for `value` and `gas`.
+ * Deprecated the identifier `now`.
 
 Language Features:
 

docs/070-breaking-changes.rst

@@ -15,3 +15,4 @@ This section gives detailed instructions on how to update prior code for every b
 
 * Change ``f.value(...)()`` to ``f{value: ...}()``. Similarly ``(new C).value(...)()`` to
   ``(new C){value: ...}()`` and ``f.gas(...)()`` to ``f{gas: ...}()``.
+* Change ``now`` to ``block.timestamp``.

docs/cheatsheet.rst

@@ -67,7 +67,7 @@ The following is the order of precedence for operators, listed in order of evalu
 | *15*       | Comma operator                      | ``,``                                      |
 +------------+-------------------------------------+--------------------------------------------+
 
-.. index:: assert, block, coinbase, difficulty, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, now, gas price, origin, revert, require, keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, send
+.. index:: assert, block, coinbase, difficulty, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, gas price, origin, revert, require, keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, send
 
 Global Variables
 ================
@@ -91,7 +91,6 @@ Global Variables
 - ``msg.data`` (``bytes``): complete calldata
 - ``msg.sender`` (``address payable``): sender of the message (current call)
 - ``msg.value`` (``uint``): number of wei sent with the message
-- ``now`` (``uint``): current block timestamp (alias for ``block.timestamp``)
 - ``tx.gasprice`` (``uint``): gas price of the transaction
 - ``tx.origin`` (``address payable``): sender of the transaction (full call chain)
 - ``assert(bool condition)``: abort execution and revert state changes if condition is ``false`` (use for internal error)
@@ -124,7 +123,7 @@ Global Variables
 - ``type(I).interfaceId`` (``bytes4``): value containing the EIP-165 interface identifier of the given interface, see :ref:`Type Information<meta-type>`.
 
 .. note::
-    Do not rely on ``block.timestamp``, ``now`` and ``blockhash`` as a source of randomness,
+    Do not rely on ``block.timestamp`` or ``blockhash`` as a source of randomness,
     unless you know what you are doing.
 
     Both the timestamp and the block hash can be influenced by miners to some degree.
@@ -144,6 +143,8 @@ Global Variables
     In version 0.5.0, the following aliases were removed: ``suicide`` as alias for ``selfdestruct``,
     ``msg.gas`` as alias for ``gasleft``, ``block.blockhash`` as alias for ``blockhash`` and
     ``sha3`` as alias for ``keccak256``.
+.. note::
+    In version 0.7.0, the alias ``now`` (for ``block.timestamp``) was removed.
 
 .. index:: visibility, public, private, external, internal
 

docs/common-patterns.rst

@@ -128,7 +128,7 @@ restrictions highly readable.
         // phase, where `msg.sender` is the account
         // creating this contract.
         address public owner = msg.sender;
-        uint public creationTime = now;
+        uint public creationTime = block.timestamp;
 
         // Modifiers can be used to change
         // the body of a function.
@@ -159,7 +159,7 @@ restrictions highly readable.
 
         modifier onlyAfter(uint _time) {
             require(
-                now >= _time,
+                block.timestamp >= _time,
                 "Function called too early."
             );
             _;
@@ -287,7 +287,7 @@ function finishes.
         // This is the current stage.
         Stages public stage = Stages.AcceptingBlindedBids;
 
-        uint public creationTime = now;
+        uint public creationTime = block.timestamp;
 
         modifier atStage(Stages _stage) {
             require(
@@ -306,10 +306,10 @@ function finishes.
         // will not take the new stage into account.
         modifier timedTransitions() {
             if (stage == Stages.AcceptingBlindedBids &&
-                        now >= creationTime + 10 days)
+                        block.timestamp >= creationTime + 10 days)
                 nextStage();
             if (stage == Stages.RevealBids &&
-                    now >= creationTime + 12 days)
+                    block.timestamp >= creationTime + 12 days)
                 nextStage();
             // The other stages transition by transaction
             _;

docs/contracts/constant-state-variables.rst

@@ -44,7 +44,7 @@ Constant
 
 For ``constant`` variables, the value has to be a constant at compile time and it has to be
 assigned where the variable is declared. Any expression
-that accesses storage, blockchain data (e.g. ``now``, ``address(this).balance`` or
+that accesses storage, blockchain data (e.g. ``block.timestamp``, ``address(this).balance`` or
 ``block.number``) or
 execution data (``msg.value`` or ``gasleft()``) or makes calls to external contracts is disallowed. Expressions
 that might have a side-effect on memory allocation are allowed, but those that

docs/contracts/functions.rst

@@ -146,7 +146,7 @@ The following statements are considered modifying the state:
 
     contract C {
         function f(uint a, uint b) public view returns (uint) {
-            return a * (b + 42) + now;
+            return a * (b + 42) + block.timestamp;
         }
     }
 

docs/examples/blind-auction.rst

@@ -61,7 +61,7 @@ to receive their money - contracts cannot activate themselves.
             address payable _beneficiary
         ) public {
             beneficiary = _beneficiary;
-            auctionEndTime = now + _biddingTime;
+            auctionEndTime = block.timestamp + _biddingTime;
         }
 
         /// Bid on the auction with the value sent
@@ -78,7 +78,7 @@ to receive their money - contracts cannot activate themselves.
             // Revert the call if the bidding
             // period is over.
             require(
-                now <= auctionEndTime,
+                block.timestamp <= auctionEndTime,
                 "Auction already ended."
             );
 
@@ -140,7 +140,7 @@ to receive their money - contracts cannot activate themselves.
             // external contracts.
 
             // 1. Conditions
-            require(now >= auctionEndTime, "Auction not yet ended.");
+            require(block.timestamp >= auctionEndTime, "Auction not yet ended.");
             require(!ended, "auctionEnd has already been called.");
 
             // 2. Effects
@@ -211,8 +211,8 @@ invalid bids.
         /// functions. `onlyBefore` is applied to `bid` below:
         /// The new function body is the modifier's body where
         /// `_` is replaced by the old function body.
-        modifier onlyBefore(uint _time) { require(now < _time); _; }
+        modifier onlyBefore(uint _time) { require(block.timestamp < _time); _; }
-        modifier onlyAfter(uint _time) { require(now > _time); _; }
+        modifier onlyAfter(uint _time) { require(block.timestamp > _time); _; }
 
         constructor(
             uint _biddingTime,
@@ -220,7 +220,7 @@ invalid bids.
             address payable _beneficiary
         ) public {
             beneficiary = _beneficiary;
-            biddingEnd = now + _biddingTime;
+            biddingEnd = block.timestamp + _biddingTime;
             revealEnd = biddingEnd + _revealTime;
         }
 
@@ -326,4 +326,4 @@ invalid bids.
             highestBidder = bidder;
             return true;
         }
-    }
+    }

docs/examples/micropayment.rst

@@ -351,7 +351,7 @@ The full contract
         {
             sender = msg.sender;
             recipient = _recipient;
-            expiration = now + duration;
+            expiration = block.timestamp + duration;
         }
 
         /// the recipient can close the channel at any time by presenting a
@@ -376,7 +376,7 @@ The full contract
         /// if the timeout is reached without the recipient closing the channel,
         /// then the Ether is released back to the sender.
         function claimTimeout() public {
-            require(now >= expiration);
+            require(block.timestamp >= expiration);
             selfdestruct(sender);
         }
 

docs/units-and-global-variables.rst

@@ -47,7 +47,7 @@ These suffixes cannot be applied to variables. For example, if you want to
 interpret a function parameter in days, you can in the following way::
 
     function f(uint start, uint daysAfter) public {
-        if (now >= start + daysAfter * 1 days) {
+        if (block.timestamp >= start + daysAfter * 1 days) {
           // ...
         }
     }
@@ -61,7 +61,7 @@ There are special variables and functions which always exist in the global
 namespace and are mainly used to provide information about the blockchain
 or are general-use utility functions.
 
-.. index:: abi, block, coinbase, difficulty, encode, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, now, gas price, origin
+.. index:: abi, block, coinbase, difficulty, encode, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, gas price, origin
 
 
 Block and Transaction Properties
@@ -78,7 +78,6 @@ Block and Transaction Properties
 - ``msg.sender`` (``address payable``): sender of the message (current call)
 - ``msg.sig`` (``bytes4``): first four bytes of the calldata (i.e. function identifier)
 - ``msg.value`` (``uint``): number of wei sent with the message
-- ``now`` (``uint``): current block timestamp (alias for ``block.timestamp``)
 - ``tx.gasprice`` (``uint``): gas price of the transaction
 - ``tx.origin`` (``address payable``): sender of the transaction (full call chain)
 
@@ -88,7 +87,7 @@ Block and Transaction Properties
     This includes calls to library functions.
 
 .. note::
-    Do not rely on ``block.timestamp``, ``now`` and ``blockhash`` as a source of randomness,
+    Do not rely on ``block.timestamp`` or ``blockhash`` as a source of randomness,
     unless you know what you are doing.
 
     Both the timestamp and the block hash can be influenced by miners to some degree.
@@ -112,6 +111,9 @@ Block and Transaction Properties
     The function ``gasleft`` was previously known as ``msg.gas``, which was deprecated in
     version 0.4.21 and removed in version 0.5.0.
 
+.. note::
+    In version 0.7.0, the alias ``now`` (for ``block.timestamp``) was removed.
+
 .. index:: abi, encoding, packed
 
 ABI Encoding and Decoding Functions
@@ -327,4 +329,3 @@ for an interface type ``I``:
     A ``bytes4`` value containing the `EIP-165 <https://eips.ethereum.org/EIPS/eip-165>`_
     interface identifier of the given interface ``I``. This identifier is defined as the ``XOR`` of all
     function selectors defined within the interface itself - excluding all inherited functions.
-

docs/using-the-compiler.rst

@@ -580,6 +580,9 @@ Available upgrade modules
 |                 |         | ``f{gas: ..., value: ...}()`` and                |
 |                 |         | ``(new C){value: ...}()``.                       |
 +-----------------+---------+--------------------------------------------------+
+| ``now``         | 0.7.0   | The ``now`` keyword is deprecated. Use           |
+|                 |         | ``block.timestamp`` instead.                     |
++-----------------+---------+--------------------------------------------------+
 
 Please read :doc:`0.5.0 release notes <050-breaking-changes>`,
 :doc:`0.6.0 release notes <060-breaking-changes>` and

libsolidity/analysis/TypeChecker.cpp

@@ -2908,6 +2908,20 @@ bool TypeChecker::visit(Identifier const& _identifier)
 			);
 	}
 
+	if (
+		MagicVariableDeclaration const* magicVar =
+		dynamic_cast<MagicVariableDeclaration const*>(annotation.referencedDeclaration)
+	)
+		if (magicVar->type()->category() == Type::Category::Integer)
+		{
+			solAssert(_identifier.name() == "now", "");
+			m_errorReporter
+				.typeError(
+					_identifier.location(),
+					"\"now\" has been deprecated. Use \"block.timestamp\" instead."
+				);
+		}
+
 	return false;
 }
 

test/compilationTests/MultiSigWallet/MultiSigWalletWithDailyLimit.sol

@@ -69,8 +69,8 @@ contract MultiSigWalletWithDailyLimit is MultiSigWallet {
         internal
         returns (bool)
     {
-        if (now > lastDay + 24 hours) {
+        if (block.timestamp > lastDay + 24 hours) {
-            lastDay = now;
+            lastDay = block.timestamp;
             spentToday = 0;
         }
         if (spentToday + amount > dailyLimit || spentToday + amount < spentToday)
@@ -88,7 +88,7 @@ contract MultiSigWalletWithDailyLimit is MultiSigWallet {
         view
         returns (uint)
     {
-        if (now > lastDay + 24 hours)
+        if (block.timestamp > lastDay + 24 hours)
             return dailyLimit;
         if (dailyLimit < spentToday)
             return 0;

test/compilationTests/corion/provider.sol

@@ -256,7 +256,7 @@ contract provider is module, safeMath, announcementTypes {
         providers[msg.sender].data[currHeight].country         = country;
         providers[msg.sender].data[currHeight].info            = info;
         providers[msg.sender].data[currHeight].currentRate     = rate;
-        providers[msg.sender].data[currHeight].create          = now;
+        providers[msg.sender].data[currHeight].create          = block.timestamp;
         providers[msg.sender].data[currHeight].lastPaidRate    = rate;
         providers[msg.sender].data[currHeight].priv            = priv;
         providers[msg.sender].data[currHeight].lastSupplyID    = currentSchellingRound;
@@ -436,7 +436,7 @@ contract provider is module, safeMath, announcementTypes {
         clients[msg.sender].lastSupplyID = currentSchellingRound;
         clients[msg.sender].paidUpTo = currentSchellingRound;
         clients[msg.sender].lastRate = providers[provider].data[currHeight].currentRate;
-        clients[msg.sender].providerConnected = now;
+        clients[msg.sender].providerConnected = block.timestamp;
         emit ENewClient(msg.sender, provider, currHeight, bal);
     }
     function partProvider() isReady external {

test/compilationTests/gnosis/Markets/Campaign.sol

@@ -55,7 +55,7 @@ contract Campaign {
     }
 
     modifier timedTransitions() {
-        if (stage == Stages.AuctionStarted && deadline < now)
+        if (stage == Stages.AuctionStarted && deadline < block.timestamp)
             stage = Stages.AuctionFailed;
         _;
     }
@@ -86,7 +86,7 @@ contract Campaign {
                 && address(_marketMaker) != address(0)
                 && _fee < FEE_RANGE
                 && _funding > 0
-                && now < _deadline);
+                && block.timestamp < _deadline);
         eventContract = _eventContract;
         marketFactory = _marketFactory;
         marketMaker = _marketMaker;

test/compilationTests/gnosis/Oracles/FutarchyOracle.sol

@@ -71,7 +71,7 @@ contract FutarchyOracle is Oracle {
         public
     {
         // Deadline is in the future
-        require(_deadline > now);
+        require(_deadline > block.timestamp);
         // Create decision event
         categoricalEvent = eventFactory.createCategoricalEvent(collateralToken, this, outcomeCount);
         // Create outcome events
@@ -131,7 +131,7 @@ contract FutarchyOracle is Oracle {
         public
     {
         // Outcome is not set yet and deadline has passed
-        require(!isSet && deadline <= now);
+        require(!isSet && deadline <= block.timestamp);
         // Find market with highest marginal price for long outcome tokens
         uint highestMarginalPrice = markets[0].marketMaker().calcMarginalPrice(markets[0], LONG);
         uint highestIndex = 0;

test/compilationTests/gnosis/Oracles/UltimateOracle.sol

@@ -80,7 +80,7 @@ contract UltimateOracle is Oracle {
                 && forwardedOutcomeSetTimestamp == 0
                 && forwardedOracle.isOutcomeSet());
         forwardedOutcome = forwardedOracle.getOutcome();
-        forwardedOutcomeSetTimestamp = now;
+        forwardedOutcomeSetTimestamp = block.timestamp;
         emit ForwardedOracleOutcomeAssignment(forwardedOutcome);
     }
 
@@ -97,7 +97,7 @@ contract UltimateOracle is Oracle {
         totalOutcomeAmounts[_outcome] = challengeAmount;
         totalAmount = challengeAmount;
         frontRunner = _outcome;
-        frontRunnerSetTimestamp = now;
+        frontRunnerSetTimestamp = block.timestamp;
         emit OutcomeChallenge(msg.sender, _outcome);
     }
 
@@ -120,7 +120,7 @@ contract UltimateOracle is Oracle {
         if (_outcome != frontRunner && totalOutcomeAmounts[_outcome] > totalOutcomeAmounts[frontRunner])
         {
             frontRunner = _outcome;
-            frontRunnerSetTimestamp = now;
+            frontRunnerSetTimestamp = block.timestamp;
         }
         emit OutcomeVote(msg.sender, _outcome, amount);
     }
@@ -147,7 +147,7 @@ contract UltimateOracle is Oracle {
         view
         returns (bool)
     {
-        return forwardedOutcomeSetTimestamp != 0 && now.sub(forwardedOutcomeSetTimestamp) > challengePeriod;
+        return forwardedOutcomeSetTimestamp != 0 && (block.timestamp).sub(forwardedOutcomeSetTimestamp) > challengePeriod;
     }
 
     /// @dev Checks if time to overbid the front runner is over
@@ -157,7 +157,7 @@ contract UltimateOracle is Oracle {
         view
         returns (bool)
     {
-        return frontRunnerSetTimestamp != 0 && now.sub(frontRunnerSetTimestamp) > frontRunnerPeriod;
+        return frontRunnerSetTimestamp != 0 && (block.timestamp).sub(frontRunnerSetTimestamp) > frontRunnerPeriod;
     }
 
     /// @dev Checks if outcome was challenged

test/compilationTests/milestonetracker/MilestoneTracker.sol

@@ -264,10 +264,10 @@ contract MilestoneTracker {
             &&(msg.sender != recipient))
             revert();
         if (milestone.status != MilestoneStatus.AcceptedAndInProgress) revert();
-        if (now < milestone.minCompletionDate) revert();
+        if (block.timestamp < milestone.minCompletionDate) revert();
-        if (now > milestone.maxCompletionDate) revert();
+        if (block.timestamp > milestone.maxCompletionDate) revert();
         milestone.status = MilestoneStatus.Completed;
-        milestone.doneTime = now;
+        milestone.doneTime = block.timestamp;
         emit ProposalStatusChanged(_idMilestone, milestone.status);
     }
 
@@ -312,7 +312,7 @@ contract MilestoneTracker {
             &&(msg.sender != recipient))
             revert();
         if  ((milestone.status != MilestoneStatus.Completed) ||
-             (now < milestone.doneTime + milestone.reviewTime))
+             (block.timestamp < milestone.doneTime + milestone.reviewTime))
             revert();
 
         authorizePayment(_idMilestone);

test/contracts/AuctionRegistrar.cpp

@@ -38,7 +38,6 @@ namespace solidity::frontend::test
 
 namespace
 {
-
 static char const* registrarCode = R"DELIMITER(
 pragma solidity >=0.4.0 <0.8.0;
 
@@ -68,7 +67,7 @@ abstract contract AuctionSystem {
 
 	function bid(string memory _name, address payable _bidder, uint _value) internal {
 		Auction storage auction = m_auctions[_name];
-		if (auction.endDate > 0 && now > auction.endDate)
+		if (auction.endDate > 0 && block.timestamp > auction.endDate)
 		{
 			emit AuctionEnded(_name, auction.highestBidder);
 			onAuctionEnd(_name);
@@ -82,7 +81,7 @@ abstract contract AuctionSystem {
 			auction.sumOfBids += _value;
 			auction.highestBid = _value;
 			auction.highestBidder = _bidder;
-			auction.endDate = now + c_biddingTime;
+			auction.endDate = block.timestamp + c_biddingTime;
 
 			emit NewBid(_name, _bidder, _value);
 		}
@@ -120,7 +119,7 @@ contract GlobalRegistrar is Registrar, AuctionSystem {
 		Auction storage auction = m_auctions[_name];
 		Record storage record = m_toRecord[_name];
 		address previousOwner = record.owner;
-		record.renewalDate = now + c_renewalInterval;
+		record.renewalDate = block.timestamp + c_renewalInterval;
 		record.owner = auction.highestBidder;
 		emit Changed(_name);
 		if (previousOwner != 0x0000000000000000000000000000000000000000) {
@@ -138,7 +137,7 @@ contract GlobalRegistrar is Registrar, AuctionSystem {
 		bool needAuction = requiresAuction(_name);
 		if (needAuction)
 		{
-			if (now < m_toRecord[_name].renewalDate)
+			if (block.timestamp < m_toRecord[_name].renewalDate)
 				revert();
 			bid(_name, msg.sender, msg.value);
 		} else {

test/contracts/Wallet.cpp

@@ -40,7 +40,6 @@ using namespace solidity::util;
 
 namespace solidity::frontend::test
 {
-
 static char const* walletCode = R"DELIMITER(
 //sol Wallet
 // Multi-sig, daily-limited account proxy/wallet.
@@ -317,7 +316,7 @@ abstract contract daylimit is multiowned {
 		return false;
 	}
 	// determines today's index.
-	function today() private view returns (uint) { return now / 1 days; }
+	function today() private view returns (uint) { return block.timestamp / 1 days; }
 
 	// FIELDS
 

test/externalTests/colony.sh

@@ -34,7 +34,7 @@ function colony_test
     FORCE_ABIv2=false
     CONFIG="truffle.js"
 
-    truffle_setup https://github.com/solidity-external-tests/colonyNetwork.git develop_060
+    truffle_setup https://github.com/solidity-external-tests/colonyNetwork.git develop_070
     run_install install_fn
 
     cd lib

test/externalTests/gnosis.sh

@@ -33,7 +33,7 @@ function gnosis_safe_test
     OPTIMIZER_LEVEL=1
     CONFIG="truffle.js"
 
-    truffle_setup https://github.com/solidity-external-tests/safe-contracts.git development_060
+    truffle_setup https://github.com/solidity-external-tests/safe-contracts.git development_070
 
     force_truffle_version
     sed -i 's|github:gnosis/mock-contract#sol_0_5_0|github:solidity-external-tests/mock-contract#master_070|g' package.json

test/externalTests/solc-js/DAO/DAO.sol

@@ -381,7 +381,7 @@ contract DAO is DAOInterface, Token, TokenCreation {
             revert();
         if (address(DAOrewardAccount) == 0x0000000000000000000000000000000000000000)
             revert();
-        lastTimeMinQuorumMet = now;
+        lastTimeMinQuorumMet = block.timestamp;
         minQuorumDivisor = 5; // sets the minimal quorum to 20%
         proposals.push(); // avoids a proposal with ID 0 because it is used
 
@@ -390,7 +390,7 @@ contract DAO is DAOInterface, Token, TokenCreation {
     }
 
     receive() external payable override(DAOInterface, TokenCreation) {
-        if (now < closingTime + creationGracePeriod && msg.sender != address(extraBalance))
+        if (block.timestamp < closingTime + creationGracePeriod && msg.sender != address(extraBalance))
             createTokenProxy(msg.sender);
         else
             receiveEther();
@@ -430,13 +430,13 @@ contract DAO is DAOInterface, Token, TokenCreation {
             revert();
 
         if (!isFueled
-            || now < closingTime
+            || block.timestamp < closingTime
             || (msg.value < proposalDeposit && !_newCurator)) {
 
             revert();
         }
 
-        if (now + _debatingPeriod < now) // prevents overflow
+        if (block.timestamp + _debatingPeriod < block.timestamp) // prevents overflow
             revert();
 
         // to prevent a 51% attacker to convert the ether into deposit
@@ -445,7 +445,7 @@ contract DAO is DAOInterface, Token, TokenCreation {
 
         // to prevent curator from halving quorum before first proposal
         if (proposals.length == 1) // initial length is 1 (see constructor)
-            lastTimeMinQuorumMet = now;
+            lastTimeMinQuorumMet = block.timestamp;
 
         Proposal storage p = proposals.push();
          _proposalID = proposals.length - 1;
@@ -453,7 +453,7 @@ contract DAO is DAOInterface, Token, TokenCreation {
         p.amount = _amount;
         p.description = _description;
         p.proposalHash = keccak256(abi.encodePacked(_recipient, _amount, _transactionData));
-        p.votingDeadline = now + _debatingPeriod;
+        p.votingDeadline = block.timestamp + _debatingPeriod;
         p.open = true;
         //p.proposalPassed = False; // that's default
         p.newCurator = _newCurator;
@@ -493,7 +493,7 @@ contract DAO is DAOInterface, Token, TokenCreation {
         Proposal storage p = proposals[_proposalID];
         if (p.votedYes[msg.sender]
             || p.votedNo[msg.sender]
-            || now >= p.votingDeadline) {
+            || block.timestamp >= p.votingDeadline) {
 
             revert();
         }
@@ -529,13 +529,13 @@ contract DAO is DAOInterface, Token, TokenCreation {
             ? splitExecutionPeriod
             : executeProposalPeriod;
         // If we are over deadline and waiting period, assert proposal is closed
-        if (p.open && now > p.votingDeadline + waitPeriod) {
+        if (p.open && block.timestamp > p.votingDeadline + waitPeriod) {
             closeProposal(_proposalID);
             return false;
         }
 
         // Check if the proposal can be executed
-        if (now < p.votingDeadline  // has the voting deadline arrived?
+        if (block.timestamp < p.votingDeadline  // has the voting deadline arrived?
             // Have the votes been counted?
             || !p.open
             || p.proposalPassed // anyone trying to call us recursively?
@@ -573,7 +573,7 @@ contract DAO is DAOInterface, Token, TokenCreation {
             if (!p.creator.send(p.proposalDeposit))
                 revert();
 
-            lastTimeMinQuorumMet = now;
+            lastTimeMinQuorumMet = block.timestamp;
             // set the minQuorum to 20% again, in the case it has been reached
             if (quorum > totalSupply / 5)
                 minQuorumDivisor = 5;
@@ -628,9 +628,9 @@ contract DAO is DAOInterface, Token, TokenCreation {
 
         // Sanity check
 
-        if (now < p.votingDeadline  // has the voting deadline arrived?
+        if (block.timestamp < p.votingDeadline  // has the voting deadline arrived?
             //The request for a split expires XX days after the voting deadline
-            || now > p.votingDeadline + splitExecutionPeriod
+            || block.timestamp > p.votingDeadline + splitExecutionPeriod
             // Does the new Curator address match?
             || p.recipient != _newCurator
             // Is it a new curator proposal?
@@ -759,7 +759,7 @@ override returns (bool _success) {
 
     function transfer(address _to, uint256 _value) public override returns (bool success) {
         if (isFueled
-            && now > closingTime
+            && block.timestamp > closingTime
             && !isBlocked(msg.sender)
             && _to != address(this)
             && transferPaidOut(msg.sender, _to, _value)
@@ -782,7 +782,7 @@ override returns (bool _success) {
     function transferFrom(address _from, address _to, uint256 _value) public
 override returns (bool success) {
         if (isFueled
-            && now > closingTime
+            && block.timestamp > closingTime
             && !isBlocked(_from)
             && _to != address(this)
             && transferPaidOut(_from, _to, _value)
@@ -869,11 +869,11 @@ override returns (bool _success) {
         // this can only be called after `quorumHalvingPeriod` has passed or at anytime after
         // fueling by the curator with a delay of at least `minProposalDebatePeriod`
         // between the calls
-        if ((lastTimeMinQuorumMet < (now - quorumHalvingPeriod) || msg.sender == curator)
+        if ((lastTimeMinQuorumMet < (block.timestamp - quorumHalvingPeriod) || msg.sender == curator)
-            && lastTimeMinQuorumMet < (now - minProposalDebatePeriod)
+            && lastTimeMinQuorumMet < (block.timestamp - minProposalDebatePeriod)
-            && now >= closingTime
+            && block.timestamp >= closingTime
             && proposals.length > 1) {
-            lastTimeMinQuorumMet = now;
+            lastTimeMinQuorumMet = block.timestamp;
             minQuorumDivisor *= 2;
             return true;
         } else {
@@ -887,7 +887,7 @@ override returns (bool _success) {
             _newCurator,
             0,
             0,
-            now + splitExecutionPeriod,
+            block.timestamp + splitExecutionPeriod,
             name,
             symbol,
             decimals
@@ -907,7 +907,7 @@ override returns (bool _success) {
         if (blocked[_account] == 0)
             return false;
         Proposal storage p = proposals[blocked[_account]];
-        if (now > p.votingDeadline) {
+        if (block.timestamp > p.votingDeadline) {
             blocked[_account] = 0;
             return false;
         } else {

test/externalTests/solc-js/DAO/TokenCreation.sol

@@ -102,7 +102,7 @@ contract TokenCreation is TokenCreationInterface, Token {
 
     function createTokenProxy(address payable _tokenHolder) payable public
 override returns (bool success) {
-        if (now < closingTime && msg.value > 0
+        if (block.timestamp < closingTime && msg.value > 0
             && (privateCreation == 0x0000000000000000000000000000000000000000 || privateCreation == msg.sender)) {
 
             uint token = (msg.value * 20) / divisor();
@@ -121,7 +121,7 @@ override returns (bool success) {
     }
 
     function refund() public override {
-        if (now > closingTime && !isFueled) {
+        if (block.timestamp > closingTime && !isFueled) {
             // Get extraBalance - will only succeed when called for the first time
             if (address(extraBalance).balance >= extraBalance.accumulatedInput())
                 extraBalance.payOut(address(this), extraBalance.accumulatedInput());
@@ -141,11 +141,11 @@ override returns (bool success) {
         // The number of (base unit) tokens per wei is calculated
         // as `msg.value` * 20 / `divisor`
         // The fueling period starts with a 1:1 ratio
-        if (closingTime - 2 weeks > now) {
+        if (closingTime - 2 weeks > block.timestamp) {
             return 20;
         // Followed by 10 days with a daily creation rate increase of 5%
-        } else if (closingTime - 4 days > now) {
+        } else if (closingTime - 4 days > block.timestamp) {
-            return (20 + (now - (closingTime - 2 weeks)) / (1 days));
+            return (20 + (block.timestamp - (closingTime - 2 weeks)) / (1 days));
         // The last 4 days there is a constant creation rate ratio of 1:1.5
         } else {
             return 30;

test/libsolidity/SolidityEndToEndTest.cpp

@@ -1025,29 +1025,6 @@ BOOST_AUTO_TEST_CASE(blockchain)
 	ABI_CHECK(callContractFunctionWithValue("someInfo()", 28), encodeArgs(28, u256("0x1212121212121212121212121212121212121212"), 7));
 }
 
-BOOST_AUTO_TEST_CASE(now)
-{
-	char const* sourceCode = R"(
-		contract test {
-			function someInfo() public returns (bool equal, uint val) {
-				equal = block.timestamp == now;
-				val = now;
-			}
-		}
-	)";
-	ALSO_VIA_YUL(
-		compileAndRun(sourceCode);
-		u256 startBlock = blockNumber();
-		size_t startTime = blockTimestamp(startBlock);
-		auto ret = callContractFunction("someInfo()");
-		u256 endBlock = blockNumber();
-		size_t endTime = blockTimestamp(endBlock);
-		BOOST_CHECK(startBlock != endBlock);
-		BOOST_CHECK(startTime != endTime);
-		ABI_CHECK(ret, encodeArgs(true, endTime));
-	)
-}
-
 BOOST_AUTO_TEST_CASE(send_ether)
 {
 	char const* sourceCode = R"(

test/libsolidity/SolidityOptimizer.cpp

@@ -346,9 +346,9 @@ BOOST_AUTO_TEST_CASE(incorrect_storage_access_bug)
 			mapping(uint => uint) data;
 			function f() public returns (uint)
 			{
-				if (data[now] == 0)
+				if (data[block.timestamp] == 0)
 					data[uint(-7)] = 5;
-				return data[now];
+				return data[block.timestamp];
 			}
 		}
 	)";

test/libsolidity/smtCheckerTests/special/many.sol

@@ -10,7 +10,7 @@ contract C
 		assert(tx.origin == msg.sender);
 		uint x = block.number;
 		assert(x + 2 > block.number);
-		assert(now > 10);
+		assert(block.timestamp > 10);
 		assert(gasleft() > 100);
 	}
 }
@@ -22,5 +22,5 @@ contract C
 // Warning: (244-275): Assertion violation happens here
 // Warning: (311-316): Overflow (resulting value larger than 2**256 - 1) happens here
 // Warning: (304-332): Assertion violation happens here
-// Warning: (336-352): Assertion violation happens here
+// Warning: (336-364): Assertion violation happens here
-// Warning: (356-379): Assertion violation happens here
+// Warning: (368-391): Assertion violation happens here

test/libsolidity/syntaxTests/globalFunctions/now_deprecate.sol

@@ -0,0 +1,7 @@
+contract C {
+	function f() public {
+		now;
+	}
+}
+// ----
+// TypeError: (38-41): "now" has been deprecated. Use "block.timestamp" instead.

test/libsolidity/syntaxTests/globalFunctions/now_override.sol

@@ -0,0 +1,8 @@
+contract C {
+	function f() public view {
+		uint now = block.timestamp;
+		now;
+	}
+}
+// ----
+// Warning: (43-51): This declaration shadows a builtin symbol.

test/libsolidity/syntaxTests/viewPureChecker/smoke_test.sol

@@ -1,7 +1,7 @@
 contract C {
     uint x;
     function g() pure public {}
-    function f() view public returns (uint) { return now; }
+    function f() view public returns (uint) { return block.timestamp; }
     function h() public { x = 2; }
     function i() payable public { x = 2; }
 }

tools/solidityUpgrade/SourceTransform.h

@@ -267,6 +267,11 @@ public:
 
 		return "";
 	}
+
+	static std::string nowUpdate(langutil::SourceLocation const& _location)
+	{
+		return regex_replace(_location.text(), std::regex{"now"}, "block.timestamp");
+	}
 };
 
 }

tools/solidityUpgrade/SourceUpgrade.cpp

@@ -196,6 +196,8 @@ Allowed options)",
 				m_suite.activateModule(Module::VirtualFunction);
 			else if (module == "dotsyntax")
 				m_suite.activateModule(Module::DotSyntax);
+			else if (module == "now")
+				m_suite.activateModule(Module::NowKeyword);
 			else
 			{
 				error() << "Unknown upgrade module \"" + module + "\"" << endl;

tools/solidityUpgrade/SourceUpgrade.h

@@ -58,7 +58,8 @@ private:
 		AbstractContract,
 		OverridingFunction,
 		VirtualFunction,
-		DotSyntax
+		DotSyntax,
+		NowKeyword
 	};
 
 	/// Upgrade suite that hosts all available modules.
@@ -84,6 +85,8 @@ private:
 			/// Solidity 0.7.0
 			if (isActivated(Module::DotSyntax))
 				DotSyntax{m_changes}.analyze(_sourceUnit);
+			if (isActivated(Module::NowKeyword))
+				NowKeyword{m_changes}.analyze(_sourceUnit);
 		}
 
 		void activateModule(Module _module) { m_modules.insert(_module); }
@@ -103,7 +106,8 @@ private:
 			Module::AbstractContract,
 			Module::OverridingFunction,
 			Module::VirtualFunction,
-			Module::DotSyntax
+			Module::DotSyntax,
+			Module::NowKeyword
 		};
 	};
 

tools/solidityUpgrade/Upgrade070.cpp

@@ -40,3 +40,22 @@ void DotSyntax::endVisit(FunctionCall const& _functionCall)
 			);
 	}
 }
+
+void NowKeyword::endVisit(Identifier const& _identifier)
+{
+	IdentifierAnnotation& annotation = _identifier.annotation();
+
+	if (
+		MagicVariableDeclaration const* magicVar =
+		dynamic_cast<MagicVariableDeclaration const*>(annotation.referencedDeclaration)
+	)
+		if (magicVar->type()->category() == Type::Category::Integer)
+		{
+			solAssert(_identifier.name() == "now", "");
+			m_changes.emplace_back(
+				UpgradeChange::Level::Safe,
+				_identifier.location(),
+				SourceTransform::nowUpdate(_identifier.location())
+			);
+		}
+}

tools/solidityUpgrade/Upgrade070.h

@@ -32,4 +32,13 @@ private:
 	void endVisit(frontend::FunctionCall const& _expression) override;
 };
 
+class NowKeyword: public AnalysisUpgrade
+{
+public:
+	using AnalysisUpgrade::AnalysisUpgrade;
+	void analyze(frontend::SourceUnit const& _sourceUnit) { _sourceUnit.accept(*this); }
+private:
+	void endVisit(frontend::Identifier const& _expression) override;
+};
+
 }