From 070077acb0c90631b74c5573dd202518b4f307b1 Mon Sep 17 00:00:00 2001
From: bun919tw <bun919tw@gmail.com>
Date: Wed, 20 Jan 2021 19:11:32 +0800
Subject: [PATCH] contracts/: fix cToken storage collision problem

---
 contracts/CErc20.sol           |  2 +-
 contracts/CTokenInterfaces.sol | 16 ++++++++--------
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/contracts/CErc20.sol b/contracts/CErc20.sol
index 6aa9b8e3c..767b35066 100644
--- a/contracts/CErc20.sol
+++ b/contracts/CErc20.sol
@@ -7,7 +7,7 @@ import "./CToken.sol";
  * @notice CTokens which wrap an EIP-20 underlying
  * @author Compound
  */
-contract CErc20 is CToken, CErc20Interface {
+contract CErc20 is CToken, CErc20Interface, CErc20StorageExtension {
     /**
      * @notice Initialize the new money market
      * @param underlying_ The address of the underlying asset
diff --git a/contracts/CTokenInterfaces.sol b/contracts/CTokenInterfaces.sol
index 7f4184962..eee45b1e2 100644
--- a/contracts/CTokenInterfaces.sol
+++ b/contracts/CTokenInterfaces.sol
@@ -245,11 +245,6 @@ contract CErc20Storage {
      * @notice Underlying asset for this CToken
      */
     address public underlying;
-
-    /**
-    * @notice Internal cash counter for this CToken. Should equal underlying.balanceOf(address(this)) for CERC20.
-    */
-    uint256 public internalCash;
 }
 
 contract CErc20Interface is CErc20Storage {
@@ -270,14 +265,19 @@ contract CErc20Interface is CErc20Storage {
     function _addReserves(uint addAmount) external returns (uint);
 }
 
-contract CDelegationStorage {
+contract CErc20StorageExtension {
     /**
      * @notice Implementation address for this contract
      */
     address public implementation;
+
+    /**
+     * @notice Internal cash counter for this CToken. Should equal underlying.balanceOf(address(this)) for CERC20.
+     */
+    uint256 public internalCash;
 }
 
-contract CDelegatorInterface is CDelegationStorage {
+contract CDelegatorInterface is CErc20StorageExtension {
     /**
      * @notice Emitted when implementation is changed
      */
@@ -292,7 +292,7 @@ contract CDelegatorInterface is CDelegationStorage {
     function _setImplementation(address implementation_, bool allowResign, bytes memory becomeImplementationData) public;
 }
 
-contract CDelegateInterface is CDelegationStorage {
+contract CDelegateInterface is CErc20StorageExtension {
     /**
      * @notice Called by the delegator on a delegate to initialize it for duty
      * @dev Should revert if any issues arise which make it unfit for delegation