Merge pull request #834 from 0xProject/fix/contracts/linter

Apply linter to nested contracts

75 files changed, 364 insertions, 309 deletions

diff --git a/packages/contracts/.solhint.json b/packages/contracts/.solhint.json
index 7e3b4dca2..076afe9f3 100644
--- a/packages/contracts/.solhint.json
+++ b/packages/contracts/.solhint.json
@@ -1,17 +1,20 @@
 {
     "extends": "default",
     "rules": {
-        "bracket-align": "warn",
-        "code-complexity": "warn",
-        "const-name-snakecase": "warn",
-        "expression-indent": "warn",
-        "function-max-lines": "warn",
-        "statement-indent": "warn",
-        "indent": ["warn", 4],
+        "avoid-low-level-calls": false,
+        "avoid-tx-origin": "warn",
+        "bracket-align": false,
+        "code-complexity": false,
+        "const-name-snakecase": "error",
+        "expression-indent": "error",
+        "function-max-lines": false,
+        "func-order": "error",
+        "indent": ["error", 4],
+        "max-line-length": ["warn", 160],
+        "no-inline-assembly": false,
         "quotes": ["error", "double"],
-        "max-line-length": ["warn", 120],
-        "separate-by-one-line-in-contract": "warn",
+        "separate-by-one-line-in-contract": "error",
         "space-after-comma": "error",
-        "func-order": "warn"
+        "statement-indent": "error"
     }
 }
diff --git a/packages/contracts/package.json b/packages/contracts/package.json
index a8bbdbe16..5c23d210e 100644
--- a/packages/contracts/package.json
+++ b/packages/contracts/package.json
@@ -30,7 +30,7 @@
         "profiler:report:html": "istanbul report html && open coverage/index.html",
         "coverage:report:lcov": "istanbul report lcov",
         "test:circleci": "yarn test",
-        "lint-contracts": "solhint src/2.0.0/**/*.sol"
+        "lint-contracts": "solhint src/2.0.0/**/**/**/**/*.sol"
     },
     "config": {
         "abis": "../migrations/artifacts/2.0.0/@(AssetProxyOwner|DummyERC20Token|DummyERC721Receiver|DummyERC721Token|ERC20Proxy|ERC721Proxy|Forwarder|Exchange|ExchangeWrapper|IAssetData|IAssetProxy|MixinAuthorizable|MultiSigWallet|MultiSigWalletWithTimeLock|TestAssetProxyOwner|TestAssetProxyDispatcher|TestLibBytes|TestLibs|TestSignatureValidator|TestValidator|TestWallet|TokenRegistry|Whitelist|WETH9|ZRXToken).json"
diff --git a/packages/contracts/src/2.0.0/forwarder/Forwarder.sol b/packages/contracts/src/2.0.0/forwarder/Forwarder.sol
index 71a4aff13..38128d93e 100644
--- a/packages/contracts/src/2.0.0/forwarder/Forwarder.sol
+++ b/packages/contracts/src/2.0.0/forwarder/Forwarder.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./MixinWethFees.sol";
@@ -25,6 +25,7 @@ import "./MixinMarketBuyTokens.sol";
 import "./MixinConstants.sol";
 import "../utils/Ownable/Ownable.sol";
 
+
 contract Forwarder is
     Ownable,
     MixinConstants,
@@ -33,7 +34,7 @@ contract Forwarder is
     MixinMarketBuyTokens,
     MixinMarketSellTokens
 {
-    uint256 MAX_UINT = 2**256 - 1;
+    uint256 constant internal MAX_UINT = 2**256 - 1;
 
     constructor (
         address _exchange,
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinConstants.sol b/packages/contracts/src/2.0.0/forwarder/MixinConstants.sol
index 18f2ba3bc..ea82e9d64 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinConstants.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinConstants.sol
@@ -16,19 +16,22 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../protocol/Exchange/Exchange.sol";
 import { WETH9 as EtherToken } from "../tokens/WETH9/WETH9.sol";
 import "../tokens/ERC20Token/IERC20Token.sol";
 
+
 contract MixinConstants {
 
-    Exchange EXCHANGE;
-    EtherToken ETHER_TOKEN;
-    IERC20Token ZRX_TOKEN;
-    bytes ZRX_ASSET_DATA;
-    bytes WETH_ASSET_DATA;
+    // solhint-disable var-name-mixedcase
+    Exchange internal EXCHANGE;
+    EtherToken internal ETHER_TOKEN;
+    IERC20Token internal ZRX_TOKEN;
+    bytes internal ZRX_ASSET_DATA;
+    bytes internal WETH_ASSET_DATA;
+    // solhint-enable var-name-mixedcase
 
     constructor (
         address _exchange,
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinERC20.sol b/packages/contracts/src/2.0.0/forwarder/MixinERC20.sol
index 53d4116d7..387c3de6b 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinERC20.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinERC20.sol
@@ -16,13 +16,13 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
+
 contract MixinERC20 {
 
-    string constant ERROR_TRANSFER_FAILED = "TRANSFER_FAILED";
-    bytes4 constant ERC20_TRANSFER_SELECTOR = bytes4(keccak256("transfer(address,uint256)"));
+    bytes4 constant internal ERC20_TRANSFER_SELECTOR = bytes4(keccak256("transfer(address,uint256)"));
 
     function transferToken(
         address token,
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinERC721.sol b/packages/contracts/src/2.0.0/forwarder/MixinERC721.sol
index b2e8803a9..b5be223b6 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinERC721.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinERC721.sol
@@ -16,17 +16,19 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../utils/LibBytes/LibBytes.sol";
 import "../tokens/ERC721Token/IERC721Token.sol";
 
+
 contract MixinERC721 {
 
     using LibBytes for bytes;
-    bytes4 constant ERC721_RECEIVED = bytes4(keccak256("onERC721Received(address,uint256,bytes)"));
-    bytes4 constant ERC721_RECEIVED_OPERATOR = bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"));
+
+    bytes4 constant internal ERC721_RECEIVED = bytes4(keccak256("onERC721Received(address,uint256,bytes)"));
+    bytes4 constant internal ERC721_RECEIVED_OPERATOR = bytes4(keccak256("onERC721Received(address,address,uint256,bytes)"));
 
     function onERC721Received(address, uint256, bytes memory)
         public
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinErrorMessages.sol b/packages/contracts/src/2.0.0/forwarder/MixinErrorMessages.sol
index c2a6ea0a4..1b3e3f488 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinErrorMessages.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinErrorMessages.sol
@@ -16,7 +16,9 @@
 
 */
 
-pragma solidity ^0.4.24;
+// solhint-disable
+pragma solidity 0.4.24;
+
 
 /// This contract is intended to serve as a reference, but is not actually used for efficiency reasons.
 contract MixinErrorMessages {
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinExpectedResults.sol b/packages/contracts/src/2.0.0/forwarder/MixinExpectedResults.sol
index 0bca7dc80..6406d1d37 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinExpectedResults.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinExpectedResults.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../utils/LibBytes/LibBytes.sol";
@@ -25,74 +25,13 @@ import "../protocol/Exchange/libs/LibMath.sol";
 import "../protocol/Exchange/libs/LibOrder.sol";
 import "./MixinConstants.sol";
 
+
 contract MixinExpectedResults is
     LibMath,
     LibFillResults,
     MixinConstants
 {
 
-    /// @dev Simulates the 0x Exchange fillOrder validation and calculations, without performing any state changes.
-    /// @param order An Order struct containing order specifications.
-    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
-    /// @return fillResults Amounts filled and fees paid by maker and taker.
-    function calculateFillResults(
-        LibOrder.Order memory order,
-        uint256 takerAssetFillAmount
-    )
-        internal
-        view
-        returns (FillResults memory fillResults)
-    {
-        LibOrder.OrderInfo memory orderInfo = EXCHANGE.getOrderInfo(order);
-        if (orderInfo.orderStatus != uint8(LibOrder.OrderStatus.FILLABLE)) {
-            return fillResults;
-        }
-        uint256 remainingTakerAssetAmount = safeSub(order.takerAssetAmount, orderInfo.orderTakerAssetFilledAmount);
-        uint256 takerAssetFilledAmount = min256(takerAssetFillAmount, remainingTakerAssetAmount);
-
-        fillResults.takerAssetFilledAmount = takerAssetFilledAmount;
-        fillResults.makerAssetFilledAmount = getPartialAmount(
-            takerAssetFilledAmount,
-            order.takerAssetAmount,
-            order.makerAssetAmount
-        );
-        fillResults.makerFeePaid = getPartialAmount(
-            takerAssetFilledAmount,
-            order.takerAssetAmount,
-            order.makerFee
-        );
-        fillResults.takerFeePaid = getPartialAmount(
-            takerAssetFilledAmount,
-            order.takerAssetAmount,
-            order.takerFee
-        );
-        return fillResults;
-    }
-
-    /// @dev Calculates a FillResults total for selling takerAssetFillAmount over all orders. 
-    ///      Including the fees required to be paid. 
-    /// @param orders An array of Order struct containing order specifications.
-    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
-    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
-    function calculateMarketSellResults(
-        LibOrder.Order[] memory orders,
-        uint256 takerAssetFillAmount
-    )
-        internal
-        view
-        returns (FillResults memory totalFillResults)
-    {
-        for (uint256 i = 0; i < orders.length; i++) {
-            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);
-            FillResults memory singleFillResult = calculateFillResults(orders[i], remainingTakerAssetFillAmount);
-            addFillResults(totalFillResults, singleFillResult);
-            if (totalFillResults.takerAssetFilledAmount == takerAssetFillAmount) {
-                break;
-            }
-        }
-        return totalFillResults;
-    }
-
     /// @dev Calculates a total FillResults for buying makerAssetFillAmount over all orders.
     ///      Including the fees required to be paid. 
     /// @param orders An array of Order struct containing order specifications.
@@ -155,4 +94,66 @@ contract MixinExpectedResults is
         }
         return totalFillResults;
     }
+
+    /// @dev Simulates the 0x Exchange fillOrder validation and calculations, without performing any state changes.
+    /// @param order An Order struct containing order specifications.
+    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
+    /// @return fillResults Amounts filled and fees paid by maker and taker.
+    function calculateFillResults(
+        LibOrder.Order memory order,
+        uint256 takerAssetFillAmount
+    )
+        internal
+        view
+        returns (FillResults memory fillResults)
+    {
+        LibOrder.OrderInfo memory orderInfo = EXCHANGE.getOrderInfo(order);
+        if (orderInfo.orderStatus != uint8(LibOrder.OrderStatus.FILLABLE)) {
+            return fillResults;
+        }
+        uint256 remainingTakerAssetAmount = safeSub(order.takerAssetAmount, orderInfo.orderTakerAssetFilledAmount);
+        uint256 takerAssetFilledAmount = min256(takerAssetFillAmount, remainingTakerAssetAmount);
+
+        fillResults.takerAssetFilledAmount = takerAssetFilledAmount;
+        fillResults.makerAssetFilledAmount = getPartialAmount(
+            takerAssetFilledAmount,
+            order.takerAssetAmount,
+            order.makerAssetAmount
+        );
+        fillResults.makerFeePaid = getPartialAmount(
+            takerAssetFilledAmount,
+            order.takerAssetAmount,
+            order.makerFee
+        );
+        fillResults.takerFeePaid = getPartialAmount(
+            takerAssetFilledAmount,
+            order.takerAssetAmount,
+            order.takerFee
+        );
+        return fillResults;
+    }
+
+    /// @dev Calculates a FillResults total for selling takerAssetFillAmount over all orders. 
+    ///      Including the fees required to be paid. 
+    /// @param orders An array of Order struct containing order specifications.
+    /// @param takerAssetFillAmount A number representing the amount of this order to fill.
+    /// @return totalFillResults Amounts filled and fees paid by maker and taker.
+    function calculateMarketSellResults(
+        LibOrder.Order[] memory orders,
+        uint256 takerAssetFillAmount
+    )
+        internal
+        view
+        returns (FillResults memory totalFillResults)
+    {
+        for (uint256 i = 0; i < orders.length; i++) {
+            uint256 remainingTakerAssetFillAmount = safeSub(takerAssetFillAmount, totalFillResults.takerAssetFilledAmount);
+            FillResults memory singleFillResult = calculateFillResults(orders[i], remainingTakerAssetFillAmount);
+            addFillResults(totalFillResults, singleFillResult);
+            if (totalFillResults.takerAssetFilledAmount == takerAssetFillAmount) {
+                break;
+            }
+        }
+        return totalFillResults;
+    }
 }
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol b/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol
index ef06fe519..165fec61f 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyTokens.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../utils/LibBytes/LibBytes.sol";
@@ -28,6 +28,7 @@ import "./MixinERC721.sol";
 import "./MixinConstants.sol";
 import "../protocol/Exchange/libs/LibOrder.sol";
 
+
 contract MixinMarketBuyTokens is
     MixinConstants,
     MixinWethFees,
@@ -62,8 +63,8 @@ contract MixinMarketBuyTokens is
         uint16  feeProportion,
         address feeRecipient
     )
-        payable
         public
+        payable
         returns (FillResults memory totalFillResults)
     {
         uint256 takerEthAmount = msg.value;
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyZrx.sol b/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyZrx.sol
index 4dbb34de3..cc98cb63d 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyZrx.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinMarketBuyZrx.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../protocol/Exchange/Exchange.sol";
@@ -25,11 +25,13 @@ import "../protocol/Exchange/libs/LibOrder.sol";
 import "../protocol/Exchange/libs/LibMath.sol";
 import "./MixinConstants.sol";
 
+
 contract MixinMarketBuyZrx is
     LibMath,
     LibFillResults,
     MixinConstants
 {
+
     /// @dev Buys zrxBuyAmount of ZRX fee tokens, taking into account the fees on buying fee tokens. This will guarantee
     ///      At least zrxBuyAmount of ZRX fee tokens are purchased (sometimes slightly over due to rounding issues).
     ///      It is possible that a request to buy 200 ZRX fee tokens will require purchasing 202 ZRX tokens
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol b/packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol
index 8c9cdb8d5..f4f509846 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinMarketSellTokens.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../protocol/Exchange/libs/LibOrder.sol";
@@ -27,6 +27,7 @@ import "./MixinERC20.sol";
 import "./MixinConstants.sol";
 import "./MixinMarketBuyZrx.sol";
 
+
 contract MixinMarketSellTokens is
     MixinConstants,
     MixinWethFees,
@@ -55,8 +56,8 @@ contract MixinMarketSellTokens is
         uint16  feeProportion,
         address feeRecipient
     )
-        payable
         public
+        payable
         returns (FillResults memory totalFillResults)
     {
         uint256 takerEthAmount = msg.value;
diff --git a/packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol b/packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol
index 9206c5fe0..92e2cebe8 100644
--- a/packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol
+++ b/packages/contracts/src/2.0.0/forwarder/MixinWethFees.sol
@@ -16,13 +16,14 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import { WETH9 as EtherToken } from "../tokens/WETH9/WETH9.sol";
 import "../protocol/Exchange/libs/LibMath.sol";
 import "./MixinConstants.sol";
 
+
 contract MixinWethFees is
     LibMath,
     MixinConstants
diff --git a/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol b/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol
index 1ceecd907..eb54fe047 100644
--- a/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol
+++ b/packages/contracts/src/2.0.0/multisig/MultiSigWallet.sol
@@ -1,6 +1,6 @@
+// solhint-disable
 pragma solidity ^0.4.10;
 
-// solhint-disable
 
 /// @title Multisignature wallet - Allows multiple parties to agree on transactions before execution.
 /// @author Stefan George - <stefan.george@consensys.net>
diff --git a/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol b/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol
index d714b661d..8c5e6e1e6 100644
--- a/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol
+++ b/packages/contracts/src/2.0.0/multisig/MultiSigWalletWithTimeLock.sol
@@ -16,11 +16,11 @@
 
 */
 
+// solhint-disable
 pragma solidity ^0.4.10;
 
 import "./MultiSigWallet.sol";
 
-// solhint-disable
 
 /// @title Multisignature wallet with time lock- Allows multiple parties to execute a transaction after a time lock has passed.
 /// @author Amir Bandeali - <amir@0xProject.com>
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
index aed62f54f..295974f97 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC20Proxy.sol
@@ -16,18 +16,20 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../utils/LibBytes/LibBytes.sol";
 import "./MixinAuthorizable.sol";
 
+
 contract ERC20Proxy is
     MixinAuthorizable
 {
     // Id of this proxy.
-    bytes4 constant PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
+    bytes4 constant internal PROXY_ID = bytes4(keccak256("ERC20Token(address)"));
     
+    // solhint-disable-next-line payable-fallback
     function () 
         external
     {
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
index b73dc36cc..43777d374 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/ERC721Proxy.sol
@@ -16,18 +16,20 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../utils/LibBytes/LibBytes.sol";
 import "./MixinAuthorizable.sol";
 
+
 contract ERC721Proxy is
     MixinAuthorizable
 {
     // Id of this proxy.
-    bytes4 constant PROXY_ID = bytes4(keccak256("ERC721Token(address,uint256,bytes)"));
+    bytes4 constant internal PROXY_ID = bytes4(keccak256("ERC721Token(address,uint256,bytes)"));
 
+    // solhint-disable-next-line payable-fallback
     function () 
         external
     {
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
index 5bc5f3a47..d21eac618 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/MixinAuthorizable.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../utils/Ownable/Ownable.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
index b4ff2d900..3e76e38dd 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetData.sol
@@ -16,7 +16,8 @@
 
 */
 
-pragma solidity ^0.4.23;
+// solhint-disable
+pragma solidity 0.4.24;
 
 
 // @dev Interface of the asset proxy's assetData.
@@ -24,12 +25,10 @@ pragma solidity ^0.4.23;
 // This argument is ABI encoded as one of the methods of this interface.
 interface IAssetData {
 
-    // solhint-disable-next-line func-name-mixedcase
     function ERC20Token(address tokenContract)
         external
         pure;
     
-    // solhint-disable-next-line func-name-mixedcase
     function ERC721Token(
         address tokenContract,
         uint256 tokenId,
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol
index 0ef1ed2e0..71491f7bb 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAssetProxy.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./IAuthorizable.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol
index 286db74aa..dd4c5fc65 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/interfaces/IAuthorizable.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../../utils/Ownable/IOwnable.sol";
@@ -26,13 +26,6 @@ contract IAuthorizable is
     IOwnable
 {
 
-    /// @dev Gets all authorized addresses.
-    /// @return Array of authorized addresses.
-    function getAuthorizedAddresses()
-        external
-        view
-        returns (address[]);
-
     /// @dev Authorizes an address.
     /// @param target Address to authorize.
     function addAuthorizedAddress(address target)
@@ -51,4 +44,11 @@ contract IAuthorizable is
         uint256 index
     )
         external;
+    
+    /// @dev Gets all authorized addresses.
+    /// @return Array of authorized addresses.
+    function getAuthorizedAddresses()
+        external
+        view
+        returns (address[] memory);
 }
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
index 4b460ea9a..1d9a70cc1 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/libs/LibAssetProxyErrors.sol
@@ -16,7 +16,8 @@
 
 */
 
-pragma solidity ^0.4.24;
+// solhint-disable
+pragma solidity 0.4.24;
 
 
 /// @dev This contract documents the revert reasons used in the AssetProxy contracts.
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol b/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol
index 66c259a23..312e1bde9 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxy/mixins/MAuthorizable.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../interfaces/IAuthorizable.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol b/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol
index 232155a6b..e7cf4ab5c 100644
--- a/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol
+++ b/packages/contracts/src/2.0.0/protocol/AssetProxyOwner/AssetProxyOwner.sol
@@ -33,7 +33,7 @@ contract AssetProxyOwner is
     // if this contract is allowed to call the AssetProxy's `removeAuthorizedAddressAtIndex` method without a time lock.
     mapping (address => bool) public isAssetProxyRegistered;
 
-    bytes4 constant REMOVE_AUTHORIZED_ADDRESS_AT_INDEX_SELECTOR = bytes4(keccak256("removeAuthorizedAddressAtIndex(address,uint256)"));
+    bytes4 constant internal REMOVE_AUTHORIZED_ADDRESS_AT_INDEX_SELECTOR = bytes4(keccak256("removeAuthorizedAddressAtIndex(address,uint256)"));
 
     /// @dev Function will revert if the transaction does not call `removeAuthorizedAddressAtIndex`
     ///      on an approved AssetProxy contract.
@@ -89,6 +89,7 @@ contract AssetProxyOwner is
     {
         Transaction storage tx = transactions[transactionId];
         tx.executed = true;
+        // solhint-disable-next-line avoid-call-value
         if (tx.destination.call.value(tx.value)(tx.data))
             Execution(transactionId);
         else {
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol b/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol
index effff82e0..7507d3da1 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/Exchange.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibConstants.sol";
@@ -28,6 +28,7 @@ import "./MixinTransactions.sol";
 import "./MixinMatchOrders.sol";
 
 
+// solhint-disable no-empty-blocks
 contract Exchange is
     MixinExchangeCore,
     MixinMatchOrders,
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
index dcfe9e1de..e9f882194 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinAssetProxyDispatcher.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../utils/Ownable/Ownable.sol";
 import "../../utils/LibBytes/LibBytes.sol";
@@ -151,6 +151,7 @@ contract MixinAssetProxyDispatcher is
                 /////// Setup Data Area ///////
                 // This area holds `assetData`.
                 let dataArea := add(cdStart, 132)
+                // solhint-disable-next-line no-empty-blocks
                 for {} lt(dataArea, cdEnd) {} {
                     mstore(dataArea, mload(assetData))
                     dataArea := add(dataArea, 32)
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
index 9e63dc1c0..cf53c3176 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinExchangeCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibConstants.sol";
@@ -49,8 +49,6 @@ contract MixinExchangeCore is
     // Orders with specified senderAddress and with a salt less than their epoch to are considered cancelled
     mapping (address => mapping (address => uint256)) public orderEpoch;
 
-    ////// Core exchange functions //////
-
     /// @dev Cancels all orders created by makerAddress with a salt less than or equal to the targetOrderEpoch
     ///      and senderAddress equal to msg.sender (or null address if msg.sender == makerAddress).
     /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
@@ -175,6 +173,7 @@ contract MixinExchangeCore is
         }
 
         // Validate order expiration
+        // solhint-disable-next-line not-rely-on-time
         if (block.timestamp >= order.expirationTimeSeconds) {
             orderInfo.orderStatus = uint8(OrderStatus.EXPIRED);
             return orderInfo;
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
index bfe838837..ba687543a 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinMatchOrders.sol
@@ -11,7 +11,7 @@
   limitations under the License.
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibConstants.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
index 78f13286f..822701459 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinSignatureValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../utils/LibBytes/LibBytes.sol";
 import "./mixins/MSignatureValidator.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
index 3b18ac733..823e14316 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinTransactions.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "./libs/LibExchangeErrors.sol";
 import "./mixins/MSignatureValidator.sol";
@@ -37,7 +37,7 @@ contract MixinTransactions is
     address public currentContextAddress;
 
     // Hash for the EIP712 ZeroEx Transaction Schema
-    bytes32 constant EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH = keccak256(abi.encodePacked(
+    bytes32 constant internal EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH = keccak256(abi.encodePacked(
         "ZeroExTransaction(",
         "uint256 salt,",
         "address signerAddress,",
@@ -45,41 +45,6 @@ contract MixinTransactions is
         ")"
     ));
 
-    /// @dev Calculates EIP712 hash of the Transaction.
-    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
-    /// @param signerAddress Address of transaction signer.
-    /// @param data AbiV2 encoded calldata.
-    /// @return EIP712 hash of the Transaction.
-    function hashZeroExTransaction(
-        uint256 salt,
-        address signerAddress,
-        bytes memory data
-    )
-        internal
-        pure
-        returns (bytes32 result)
-    {
-        bytes32 schemaHash = EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH;
-        bytes32 dataHash = keccak256(data);
-        // Assembly for more efficiently computing:
-        // keccak256(abi.encode(
-        //   EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH,
-        //   salt,
-        //   signerAddress,
-        //   keccak256(data)
-        //  ));
-        assembly {
-            let memPtr := mload(64)
-            mstore(memPtr, schemaHash)
-            mstore(add(memPtr, 32), salt)
-            mstore(add(memPtr, 64), and(signerAddress, 0xffffffffffffffffffffffffffffffffffffffff))
-            mstore(add(memPtr, 96), dataHash)
-            result := keccak256(memPtr, 128)
-        }
-
-        return result;
-    }
-
     /// @dev Executes an exchange method call in the context of signer.
     /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
     /// @param signerAddress Address of transaction signer.
@@ -139,6 +104,41 @@ contract MixinTransactions is
         currentContextAddress = address(0);
     }
 
+    /// @dev Calculates EIP712 hash of the Transaction.
+    /// @param salt Arbitrary number to ensure uniqueness of transaction hash.
+    /// @param signerAddress Address of transaction signer.
+    /// @param data AbiV2 encoded calldata.
+    /// @return EIP712 hash of the Transaction.
+    function hashZeroExTransaction(
+        uint256 salt,
+        address signerAddress,
+        bytes memory data
+    )
+        internal
+        pure
+        returns (bytes32 result)
+    {
+        bytes32 schemaHash = EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH;
+        bytes32 dataHash = keccak256(data);
+        // Assembly for more efficiently computing:
+        // keccak256(abi.encode(
+        //   EIP712_ZEROEX_TRANSACTION_SCHEMA_HASH,
+        //   salt,
+        //   signerAddress,
+        //   keccak256(data)
+        //  ));
+        assembly {
+            let memPtr := mload(64)
+            mstore(memPtr, schemaHash)
+            mstore(add(memPtr, 32), salt)
+            mstore(add(memPtr, 64), and(signerAddress, 0xffffffffffffffffffffffffffffffffffffffff))
+            mstore(add(memPtr, 96), dataHash)
+            result := keccak256(memPtr, 128)
+        }
+
+        return result;
+    }
+
     /// @dev The current function will be called in the context of this address (either 0x transaction signer or `msg.sender`).
     ///      If calling a fill function, this address will represent the taker.
     ///      If calling a cancel function, this address will represent the maker.
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
index 678d0252a..a16d2f897 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/MixinWrapperFunctions.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./libs/LibMath.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
index b73881c07..8db8d6f6c 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IAssetProxyDispatcher.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 contract IAssetProxyDispatcher {
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol
index 05e5dedf4..b92abba04 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchange.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./IExchangeCore.sol";
@@ -27,6 +27,7 @@ import "./IAssetProxyDispatcher.sol";
 import "./IWrapperFunctions.sol";
 
 
+// solhint-disable no-empty-blocks
 contract IExchange is
     IExchangeCore,
     IMatchOrders,
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol
index 2b573eb1a..9995e0385 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IExchangeCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../libs/LibOrder.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol
index d44116474..cea5adbbb 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IMatchOrders.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../libs/LibOrder.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol
index c5a4a57e1..1fd0eccf0 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ISignatureValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 contract ISignatureValidator {
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol
index aaaee389f..4446c55ce 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/ITransactions.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 contract ITransactions {
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol
index 2c0a5dbe2..2dd69100c 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.23;
+pragma solidity 0.4.24;
 
 
 contract IValidator {
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol
index c2db4a5b1..c97161ca6 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWallet.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 contract IWallet {
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol
index 04257b883..7c8b12724 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/interfaces/IWrapperFunctions.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../libs/LibOrder.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol
index 76200ec44..6918d755e 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibConstants.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 contract LibConstants {
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol
index 2bd7b60d4..1fc41dafd 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibEIP712.sol
@@ -16,18 +16,18 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 contract LibEIP712 {
     // EIP191 header for EIP712 prefix
-    string constant EIP191_HEADER = "\x19\x01";
+    string constant internal EIP191_HEADER = "\x19\x01";
 
     // EIP712 Domain Name value
-    string constant EIP712_DOMAIN_NAME = "0x Protocol";
+    string constant internal EIP712_DOMAIN_NAME = "0x Protocol";
 
     // EIP712 Domain Version value
-    string constant EIP712_DOMAIN_VERSION = "2";
+    string constant internal EIP712_DOMAIN_VERSION = "2";
 
     // Hash of the EIP712 Domain Separator Schema
     bytes32 public constant EIP712_DOMAIN_SEPARATOR_SCHEMA_HASH = keccak256(abi.encodePacked(
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol
index 99f683e1a..a0f75bc06 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibExchangeErrors.sol
@@ -16,7 +16,8 @@
 
 */
 
-pragma solidity ^0.4.24;
+// solhint-disable
+pragma solidity 0.4.24;
 
 
 /// @dev This contract documents the revert reasons used in the Exchange contract.
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol
index 35fa9ac0f..1b4181d94 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibFillResults.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../../utils/SafeMath/SafeMath.sol";
 
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
index 9da784854..46c13d390 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibMath.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../../utils/SafeMath/SafeMath.sol";
 
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol
index dda581d9f..2ea864a5a 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/libs/LibOrder.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "./LibEIP712.sol";
 
@@ -26,7 +26,7 @@ contract LibOrder is
 {
 
     // Hash for the EIP712 Order Schema
-    bytes32 constant EIP712_ORDER_SCHEMA_HASH = keccak256(abi.encodePacked(
+    bytes32 constant internal EIP712_ORDER_SCHEMA_HASH = keccak256(abi.encodePacked(
         "Order(",
         "address makerAddress,",
         "address takerAddress,",
@@ -55,6 +55,7 @@ contract LibOrder is
         CANCELLED                    // Order has been cancelled
     }
 
+    // solhint-disable max-line-length
     struct Order {
         address makerAddress;           // Address that created the order.      
         address takerAddress;           // Address that is allowed to fill the order. If set to 0, any address is allowed to fill the order.          
@@ -69,6 +70,7 @@ contract LibOrder is
         bytes makerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring makerAsset. The last byte references the id of this proxy.
         bytes takerAssetData;           // Encoded data that can be decoded by a specified proxy contract when transferring takerAsset. The last byte references the id of this proxy.
     }
+    // solhint-enable max-line-length
 
     struct OrderInfo {
         uint8 orderStatus;                    // Status that describes order's validity and fillability.
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
index 367b37e80..9207dfdc2 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MAssetProxyDispatcher.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../interfaces/IAssetProxyDispatcher.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
index e28d9d25b..9e3b5a2e2 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MExchangeCore.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../libs/LibOrder.sol";
@@ -102,7 +102,6 @@ contract MExchangeCore is
         internal
         view;
 
-
     /// @dev Validates context for cancelOrder. Succeeds or throws.
     /// @param order to be cancelled.
     /// @param orderInfo OrderStatus, orderHash, and amount already filled of order.
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol
index 289514b24..a31ec1585 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MMatchOrders.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../libs/LibOrder.sol";
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
index 83650b4aa..f14f2ba00 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MSignatureValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../interfaces/ISignatureValidator.sol";
 
diff --git a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol
index a9fa6d4e2..f2b5e4b16 100644
--- a/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol
+++ b/packages/contracts/src/2.0.0/protocol/Exchange/mixins/MTransactions.sol
@@ -15,7 +15,7 @@
   limitations under the License.
 
 */
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../interfaces/ITransactions.sol";
 
diff --git a/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol b/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol
index 7a2702449..44b0777b8 100644
--- a/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol
+++ b/packages/contracts/src/2.0.0/test/DummyERC20Token/DummyERC20Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../Mintable/Mintable.sol";
diff --git a/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol b/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol
index b027ac960..5dce74a14 100644
--- a/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol
+++ b/packages/contracts/src/2.0.0/test/DummyERC721Receiver/DummyERC721Receiver.sol
@@ -23,7 +23,7 @@ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../tokens/ERC721Token/IERC721Receiver.sol";
 
diff --git a/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol b/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
index de76f10c5..ba647fea4 100644
--- a/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
+++ b/packages/contracts/src/2.0.0/test/DummyERC721Token/DummyERC721Token.sol
@@ -16,13 +16,14 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../tokens/ERC721Token/ERC721Token.sol";
 import "../../utils/Ownable/Ownable.sol";
 
 
+// solhint-disable no-empty-blocks
 contract DummyERC721Token is
     Ownable,
     ERC721Token
diff --git a/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol b/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol
index f20e2a944..2fa0e3c5e 100644
--- a/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol
+++ b/packages/contracts/src/2.0.0/test/ExchangeWrapper/ExchangeWrapper.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../protocol/Exchange/interfaces/IExchange.sol";
@@ -27,7 +27,7 @@ contract ExchangeWrapper {
 
     // Exchange contract.
     // solhint-disable-next-line var-name-mixedcase
-    IExchange EXCHANGE;
+    IExchange internal EXCHANGE;
 
     constructor (address _exchange)
         public
@@ -35,6 +35,35 @@ contract ExchangeWrapper {
         EXCHANGE = IExchange(_exchange);
     }
 
+    /// @dev Cancels all orders created by sender with a salt less than or equal to the targetOrderEpoch
+    ///      and senderAddress equal to this contract.
+    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
+    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
+    /// @param makerSignature Proof that maker wishes to call this function with given params.
+    function cancelOrdersUpTo(
+        uint256 targetOrderEpoch,
+        uint256 salt,
+        bytes makerSignature
+    )
+        external
+    {
+        address makerAddress = msg.sender;
+
+        // Encode arguments into byte array.
+        bytes memory data = abi.encodeWithSelector(
+            EXCHANGE.cancelOrdersUpTo.selector,
+            targetOrderEpoch
+        );
+
+        // Call `cancelOrdersUpTo` via `executeTransaction`.
+        EXCHANGE.executeTransaction(
+            salt,
+            makerAddress,
+            data,
+            makerSignature
+        );
+    }
+
     /// @dev Fills an order using `msg.sender` as the taker.
     /// @param order Order struct containing order specifications.
     /// @param takerAssetFillAmount Desired amount of takerAsset to sell.
@@ -68,33 +97,4 @@ contract ExchangeWrapper {
             takerSignature
         );
     }
-
-    /// @dev Cancels all orders created by sender with a salt less than or equal to the targetOrderEpoch
-    ///      and senderAddress equal to this contract.
-    /// @param targetOrderEpoch Orders created with a salt less or equal to this value will be cancelled.
-    /// @param salt Arbitrary value to gaurantee uniqueness of 0x transaction hash.
-    /// @param makerSignature Proof that maker wishes to call this function with given params.
-    function cancelOrdersUpTo(
-        uint256 targetOrderEpoch,
-        uint256 salt,
-        bytes makerSignature
-    )
-        external
-    {
-        address makerAddress = msg.sender;
-
-        // Encode arguments into byte array.
-        bytes memory data = abi.encodeWithSelector(
-            EXCHANGE.cancelOrdersUpTo.selector,
-            targetOrderEpoch
-        );
-
-        // Call `cancelOrdersUpTo` via `executeTransaction`.
-        EXCHANGE.executeTransaction(
-            salt,
-            makerAddress,
-            data,
-            makerSignature
-        );
-    }
 }
diff --git a/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol b/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol
index bccb74ce8..747ac7a86 100644
--- a/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol
+++ b/packages/contracts/src/2.0.0/test/Mintable/Mintable.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol";
diff --git a/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol b/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
index be7fea7d3..76f1c6290 100644
--- a/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
+++ b/packages/contracts/src/2.0.0/test/TestAssetProxyDispatcher/TestAssetProxyDispatcher.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../protocol/Exchange/MixinAssetProxyDispatcher.sol";
diff --git a/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol b/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
index ddcc62f35..d6b6b29f2 100644
--- a/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
+++ b/packages/contracts/src/2.0.0/test/TestAssetProxyOwner/TestAssetProxyOwner.sol
@@ -16,14 +16,16 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../protocol/AssetProxyOwner/AssetProxyOwner.sol";
 
 
+// solhint-disable no-empty-blocks
 contract TestAssetProxyOwner is
     AssetProxyOwner
 {
+
     constructor(
         address[] memory _owners,
         address[] memory _assetProxyContracts,
@@ -32,11 +34,11 @@ contract TestAssetProxyOwner is
     )
         public
         AssetProxyOwner(_owners, _assetProxyContracts, _required, _secondsTimeLocked)
-    {
-    }
+    {}
     
     function testValidRemoveAuthorizedAddressAtIndexTx(uint256 id)
         public
+        view
         validRemoveAuthorizedAddressAtIndexTx(id)
         returns (bool)
     {
diff --git a/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol b/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol
index f52f635e1..8b9c00590 100644
--- a/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol
+++ b/packages/contracts/src/2.0.0/test/TestLibBytes/TestLibBytes.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../utils/LibBytes/LibBytes.sol";
diff --git a/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
index df8eb55ce..40e2c84dc 100644
--- a/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
+++ b/packages/contracts/src/2.0.0/test/TestLibs/TestLibs.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../protocol/Exchange/libs/LibMath.sol";
diff --git a/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol b/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol
index 591ae3378..235c77d17 100644
--- a/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol
+++ b/packages/contracts/src/2.0.0/test/TestSignatureValidator/TestSignatureValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../protocol/Exchange/MixinSignatureValidator.sol";
diff --git a/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol b/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol
index 5076dedc9..6278aede0 100644
--- a/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol
+++ b/packages/contracts/src/2.0.0/test/TestValidator/TestValidator.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../protocol/Exchange/interfaces/IValidator.sol";
 
@@ -27,7 +27,7 @@ contract TestValidator is
 
     // The single valid signer for this wallet.
     // solhint-disable-next-line var-name-mixedcase
-    address VALID_SIGNER;
+    address internal VALID_SIGNER;
 
     /// @dev constructs a new `TestValidator` with a single valid signer.
     /// @param validSigner The sole, valid signer.
@@ -40,6 +40,7 @@ contract TestValidator is
     /// @param signerAddress Address that should have signed the given hash.
     /// @param signature Proof of signing.
     /// @return Validity of signature.
+    // solhint-disable no-unused-vars
     function isValidSignature(
         bytes32 hash,
         address signerAddress,
@@ -51,4 +52,5 @@ contract TestValidator is
     {
         return (signerAddress == VALID_SIGNER);
     }
+    // solhint-enable no-unused-vars
 }
diff --git a/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol b/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol
index 07dfac588..0415823e3 100644
--- a/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol
+++ b/packages/contracts/src/2.0.0/test/TestWallet/TestWallet.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "../../protocol/Exchange/interfaces/IWallet.sol";
 import "../../utils/LibBytes/LibBytes.sol";
@@ -27,11 +27,9 @@ contract TestWallet is
 {
     using LibBytes for bytes;
 
-    string constant LENGTH_65_REQUIRED = "LENGTH_65_REQUIRED";
-
     // The owner of this wallet.
     // solhint-disable-next-line var-name-mixedcase
-    address WALLET_OWNER;
+    address internal WALLET_OWNER;
 
     /// @dev constructs a new `TestWallet` with a single owner.
     /// @param walletOwner The owner of this wallet.
@@ -54,7 +52,7 @@ contract TestWallet is
     {
         require(
             eip712Signature.length == 65,
-            LENGTH_65_REQUIRED
+            "LENGTH_65_REQUIRED"
         );
 
         uint8 v = uint8(eip712Signature[0]);
diff --git a/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol b/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
index 07bd7d531..60cac26ea 100644
--- a/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
+++ b/packages/contracts/src/2.0.0/test/Whitelist/Whitelist.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../../protocol/Exchange/interfaces/IExchange.sol";
@@ -27,28 +27,22 @@ import "../../utils/Ownable/Ownable.sol";
 contract Whitelist is
     Ownable
 {
-    // Revert reasons
-    string constant MAKER_NOT_WHITELISTED = "MAKER_NOT_WHITELISTED"; // Maker address not whitelisted.
-    string constant TAKER_NOT_WHITELISTED = "TAKER_NOT_WHITELISTED"; // Taker address not whitelisted.
-    string constant INVALID_SENDER = "INVALID_SENDER"; // Sender must equal transaction origin.
 
     // Mapping of address => whitelist status.
     mapping (address => bool) public isWhitelisted;
 
     // Exchange contract.
-    // solhint-disable-next-line var-name-mixedcase
-    IExchange EXCHANGE;
+    // solhint-disable var-name-mixedcase
+    IExchange internal EXCHANGE;
+    bytes internal TX_ORIGIN_SIGNATURE;
+    // solhint-enable var-name-mixedcase
 
-    byte constant VALIDATOR_SIGNATURE_BYTE = "\x06";
-    // solhint-disable-next-line var-name-mixedcase
-    bytes TX_ORIGIN_SIGNATURE;
+    byte constant internal VALIDATOR_SIGNATURE_BYTE = "\x06";
 
     constructor (address _exchange)
         public
     {
-        // solhint-disable-next-line var-name-mixedcase
         EXCHANGE = IExchange(_exchange);
-        // solhint-disable-next-line var-name-mixedcase
         TX_ORIGIN_SIGNATURE = abi.encodePacked(address(this), VALIDATOR_SIGNATURE_BYTE);
     }
 
@@ -65,6 +59,27 @@ contract Whitelist is
         isWhitelisted[target] = isApproved;
     }
 
+    /// @dev Verifies signer is same as signer of current Ethereum transaction.
+    ///      NOTE: This function can currently be used to validate signatures coming from outside of this contract.
+    ///      Extra safety checks can be added for a production contract.
+    /// @param signerAddress Address that should have signed the given hash.
+    /// @param signature Proof of signing.
+    /// @return Validity of order signature.
+    // solhint-disable no-unused-vars
+    function isValidSignature(
+        bytes32 hash,
+        address signerAddress,
+        bytes signature
+    )
+        external
+        view
+        returns (bool isValid)
+    {
+        // solhint-disable-next-line avoid-tx-origin
+        return signerAddress == tx.origin;
+    }
+    // solhint-enable no-unused-vars
+
     /// @dev Fills an order using `msg.sender` as the taker.
     ///      The transaction will revert if both the maker and taker are not whitelisted.
     ///      Orders should specify this contract as the `senderAddress` in order to gaurantee
@@ -85,20 +100,21 @@ contract Whitelist is
 
         // This contract must be the entry point for the transaction.
         require(
+            // solhint-disable-next-line avoid-tx-origin
             takerAddress == tx.origin,
-            INVALID_SENDER
+            "INVALID_SENDER"
         );
 
         // Check if maker is on the whitelist.
         require(
             isWhitelisted[order.makerAddress],
-            MAKER_NOT_WHITELISTED
+            "MAKER_NOT_WHITELISTED"
         );
 
         // Check if taker is on the whitelist.
         require(
             isWhitelisted[takerAddress],
-            TAKER_NOT_WHITELISTED
+            "TAKER_NOT_WHITELISTED"
         );
 
         // Encode arguments into byte array.
@@ -117,22 +133,4 @@ contract Whitelist is
             TX_ORIGIN_SIGNATURE
         );
     }
-
-    /// @dev Verifies signer is same as signer of current Ethereum transaction.
-    ///      NOTE: This function can currently be used to validate signatures coming from outside of this contract.
-    ///      Extra safety checks can be added for a production contract.
-    /// @param signerAddress Address that should have signed the given hash.
-    /// @param signature Proof of signing.
-    /// @return Validity of order signature.
-    function isValidSignature(
-        bytes32 hash,
-        address signerAddress,
-        bytes signature
-    )
-        external
-        view
-        returns (bool isValid)
-    {
-        return signerAddress == tx.origin;
-    }
 }
diff --git a/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
index 59dc7d7bf..58ffdfcb6 100644
--- a/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC20Token/ERC20Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "./IERC20Token.sol";
@@ -24,12 +24,8 @@ import "./IERC20Token.sol";
 
 contract ERC20Token is IERC20Token {
 
-    string constant INSUFFICIENT_BALANCE = "ERC20_INSUFFICIENT_BALANCE";
-    string constant INSUFFICIENT_ALLOWANCE = "ERC20_INSUFFICIENT_ALLOWANCE";
-    string constant OVERFLOW = "Transfer would result in an overflow.";
-
-    mapping (address => uint256) balances;
-    mapping (address => mapping (address => uint256)) allowed;
+    mapping (address => uint256) internal balances;
+    mapping (address => mapping (address => uint256)) internal allowed;
 
     uint256 public totalSupply;
 
@@ -39,11 +35,11 @@ contract ERC20Token is IERC20Token {
     {
         require(
             balances[msg.sender] >= _value,
-            INSUFFICIENT_BALANCE
+            "ERC20_INSUFFICIENT_BALANCE"
         );
         require(
             balances[_to] + _value >= balances[_to],
-            OVERFLOW
+            "OVERFLOW"
         );
         balances[msg.sender] -= _value;
         balances[_to] += _value;
@@ -57,15 +53,15 @@ contract ERC20Token is IERC20Token {
     {
         require(
             balances[_from] >= _value,
-            INSUFFICIENT_BALANCE
+            "ERC20_INSUFFICIENT_BALANCE"
         );
         require(
             allowed[_from][msg.sender] >= _value,
-            INSUFFICIENT_ALLOWANCE
+            "ERC20_INSUFFICIENT_ALLOWANCE"
         );
         require(
             balances[_to] + _value >= balances[_to],
-            OVERFLOW
+            "OVERFLOW"
         );
         balances[_to] += _value;
         balances[_from] -= _value;
@@ -84,7 +80,8 @@ contract ERC20Token is IERC20Token {
     }
 
     function balanceOf(address _owner)
-        public view
+        public
+        view
         returns (uint256)
     {
         return balances[_owner];
diff --git a/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol b/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol
index de4ed2af9..e3e193666 100644
--- a/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC20Token/IERC20Token.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 
@@ -60,6 +60,7 @@ contract IERC20Token {
         public view
         returns (uint256);
 
+    // solhint-disable-next-line no-simple-event-func-name
     event Transfer(
         address indexed _from,
         address indexed _to,
diff --git a/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol
index defb506a8..60603aa19 100644
--- a/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/ERC721Token.sol
@@ -23,7 +23,7 @@ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 import "./IERC721Token.sol";
 import "./IERC721Receiver.sol";
@@ -41,7 +41,7 @@ contract ERC721Token is
 {
     // Equals to `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`
     // which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
-    bytes4 constant ERC721_RECEIVED = 0xf0b9e5ba;
+    bytes4 constant internal ERC721_RECEIVED = 0xf0b9e5ba;
 
     // Mapping from token ID to owner
     mapping (uint256 => address) internal tokenOwner;
@@ -73,7 +73,7 @@ contract ERC721Token is
         _;
     }
 
-    function ERC721Token(
+    constructor (
         string _name,
         string _symbol)
         public
diff --git a/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol
index f72c75638..f2e8f3c88 100644
--- a/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Receiver.sol
@@ -23,7 +23,7 @@ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 /**
@@ -38,7 +38,7 @@ contract IERC721Receiver {
     *  Equals to `bytes4(keccak256("onERC721Received(address,uint256,bytes)"))`,
     *  which can be also obtained as `ERC721Receiver(0).onERC721Received.selector`
     */
-    bytes4 constant ERC721_RECEIVED = 0xf0b9e5ba;
+    bytes4 constant internal ERC721_RECEIVED = 0xf0b9e5ba;
 
     /**
     * @notice Handle the receipt of an NFT
diff --git a/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol
index 0d64ee861..4d57ece38 100644
--- a/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol
+++ b/packages/contracts/src/2.0.0/tokens/ERC721Token/IERC721Token.sol
@@ -23,7 +23,7 @@ TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 /**
@@ -40,11 +40,13 @@ contract IERC721Token {
         address indexed _to,
         uint256 _tokenId
     );
+
     event Approval(
         address indexed _owner,
         address indexed _approved,
         uint256 _tokenId
     );
+
     event ApprovalForAll(
         address indexed _owner,
         address indexed _operator,
@@ -55,6 +57,7 @@ contract IERC721Token {
         public
         view
         returns (string);
+
     function symbol()
         public
         view
@@ -64,10 +67,12 @@ contract IERC721Token {
         public
         view
         returns (uint256 _balance);
+
     function ownerOf(uint256 _tokenId)
         public
         view
         returns (address _owner);
+
     function exists(uint256 _tokenId)
         public
         view
@@ -75,6 +80,7 @@ contract IERC721Token {
 
     function approve(address _to, uint256 _tokenId)
         public;
+
     function getApproved(uint256 _tokenId)
         public
         view
@@ -82,6 +88,7 @@ contract IERC721Token {
 
     function setApprovalForAll(address _operator, bool _approved)
         public;
+
     function isApprovedForAll(address _owner, address _operator)
         public
         view
@@ -90,17 +97,22 @@ contract IERC721Token {
     function transferFrom(
         address _from,
         address _to,
-        uint256 _tokenId)
+        uint256 _tokenId
+    )
         public;
+
     function safeTransferFrom(
         address _from,
         address _to,
-        uint256 _tokenId)
+        uint256 _tokenId
+    )
         public;
+
     function safeTransferFrom(
         address _from,
         address _to,
         uint256 _tokenId,
-        bytes _data)
+        bytes _data
+    )
         public;
 }
diff --git a/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol b/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
index 845324e4e..a974503ca 100644
--- a/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
+++ b/packages/contracts/src/2.0.0/tokens/UnlimitedAllowanceToken/UnlimitedAllowanceToken.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 import "../ERC20Token/ERC20Token.sol";
@@ -24,7 +24,7 @@ import "../ERC20Token/ERC20Token.sol";
 
 contract UnlimitedAllowanceToken is ERC20Token {
 
-    uint256 constant MAX_UINT = 2**256 - 1;
+    uint256 constant internal MAX_UINT = 2**256 - 1;
 
     /// @dev ERC20 transferFrom, modified such that an allowance of MAX_UINT represents an unlimited allowance. See https://github.com/ethereum/EIPs/issues/717
     /// @param _from Address to transfer from.
@@ -38,15 +38,15 @@ contract UnlimitedAllowanceToken is ERC20Token {
         uint256 allowance = allowed[_from][msg.sender];
         require(
             balances[_from] >= _value,
-            INSUFFICIENT_BALANCE
+            "ERC20_INSUFFICIENT_BALANCE"
         );
         require(
             allowance >= _value,
-            INSUFFICIENT_ALLOWANCE
+            "ERC20_INSUFFICIENT_ALLOWANCE"
         );
         require(
             balances[_to] + _value >= balances[_to],
-            OVERFLOW
+            "OVERFLOW"
         );
         balances[_to] += _value;
         balances[_from] -= _value;
diff --git a/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol b/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol
index 378a507b9..1fdb04de5 100644
--- a/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol
+++ b/packages/contracts/src/2.0.0/tokens/WETH9/WETH9.sol
@@ -13,6 +13,7 @@
 // You should have received a copy of the GNU General Public License
 // along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
+// solhint-disable
 pragma solidity ^0.4.18;
 
 
diff --git a/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol b/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol
index ed0670072..28c0b2fb3 100644
--- a/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol
+++ b/packages/contracts/src/2.0.0/tokens/ZRXToken/ZRXToken.sol
@@ -16,20 +16,24 @@
 
 */
 
-pragma solidity ^0.4.11;
+pragma solidity 0.4.11;
 
+// solhint-disable-next-line max-line-length
 import { UnlimitedAllowanceToken_v1 as UnlimitedAllowanceToken } from "../../../1.0.0/UnlimitedAllowanceToken/UnlimitedAllowanceToken_v1.sol";
 
 
-
 contract ZRXToken is UnlimitedAllowanceToken {
 
+    // solhint-disable const-name-snakecase
     uint8 constant public decimals = 18;
     uint public totalSupply = 10**27; // 1 billion tokens, 18 decimal places
     string constant public name = "0x Protocol Token";
     string constant public symbol = "ZRX";
+    // solhint-enableconst-name-snakecase
 
-    function ZRXToken() {
+    function ZRXToken()
+        public
+    {
         balances[msg.sender] = totalSupply;
     }
 }
diff --git a/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol b/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
index c2fff5efb..01d34fa8f 100644
--- a/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
+++ b/packages/contracts/src/2.0.0/utils/LibBytes/LibBytes.sol
@@ -16,7 +16,7 @@
 
 */
 
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 
 
 library LibBytes {
@@ -115,6 +115,7 @@ library LibBytes {
                     // Copy whole words front to back
                     // Note: the first check is always true,
                     // this could have been a do-while loop.
+                    // solhint-disable-next-line no-empty-blocks
                     for {} lt(source, sEnd) {} {
                         mstore(dest, mload(source))
                         source := add(source, 32)
@@ -145,6 +146,7 @@ library LibBytes {
                     // 2**255, so they can be safely re-interpreted as signed.
                     // Note: the first check is always true,
                     // this could have been a do-while loop.
+                    // solhint-disable-next-line no-empty-blocks
                     for {} slt(dest, dEnd) {} {
                         mstore(dEnd, mload(sEnd))
                         sEnd := sub(sEnd, 32)
@@ -157,13 +159,17 @@ library LibBytes {
             }
         }
     }
-    
+
     /// @dev Returns a slices from a byte array.
     /// @param b The byte array to take a slice from.
     /// @param from The starting index for the slice (inclusive).
     /// @param to The final index for the slice (exclusive).
     /// @return result The slice containing bytes at indices [from, to)
-    function slice(bytes memory b, uint256 from, uint256 to)
+    function slice(
+        bytes memory b,
+        uint256 from,
+        uint256 to
+    )
         internal
         pure
         returns (bytes memory result)
@@ -192,7 +198,11 @@ library LibBytes {
     /// @param to The final index for the slice (exclusive).
     /// @return result The slice containing bytes at indices [from, to)
     /// @dev When `from == 0`, the original array will match the slice. In other cases its state will be corrupted.
-    function sliceDestructive(bytes memory b, uint256 from, uint256 to)
+    function sliceDestructive(
+        bytes memory b,
+        uint256 from,
+        uint256 to
+    )
         internal
         pure
         returns (bytes memory result)
@@ -344,7 +354,10 @@ library LibBytes {
             // 1. Add index to address of bytes array
             // 2. Load 32-byte word from memory
             // 3. Apply 12-byte mask to obtain extra bytes occupying word of memory where we'll store the address
-            let neighbors := and(mload(add(b, index)), 0xffffffffffffffffffffffff0000000000000000000000000000000000000000)
+            let neighbors := and(
+                mload(add(b, index)),
+                0xffffffffffffffffffffffff0000000000000000000000000000000000000000
+            )
             
             // Make sure input address is clean.
             // (Solidity does not guarantee this)
@@ -509,7 +522,7 @@ library LibBytes {
         // Assert length of <b> is valid, given
         // length of input
         require(
-            b.length >= index + 32 /* 32 bytes to store length */ + input.length,
+            b.length >= index + 32 + input.length,  // 32 bytes to store length
             "GREATER_OR_EQUAL_TO_NESTED_BYTES_LENGTH_REQUIRED"
         );
 
diff --git a/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol b/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol
index e77680903..36563d837 100644
--- a/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol
+++ b/packages/contracts/src/2.0.0/utils/Ownable/IOwnable.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 /*
diff --git a/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol b/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
index 489793a95..81a14a447 100644
--- a/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
+++ b/packages/contracts/src/2.0.0/utils/Ownable/Ownable.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;
 
 /*
diff --git a/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol b/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol
index ec0a3fe76..8cbb8e526 100644
--- a/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol
+++ b/packages/contracts/src/2.0.0/utils/SafeMath/SafeMath.sol
@@ -1,4 +1,4 @@
-pragma solidity ^0.4.24;
+pragma solidity 0.4.24;
 pragma experimental ABIEncoderV2;