Merge pull request #4438 from ethereum/address_members_external_tests_docs

Address members used by contracts: update external tests and docs

docs/contracts.rst

@@ -406,7 +406,7 @@ Constant State Variables
 
 State variables can be declared as ``constant``. In this case, they have to be
 assigned from an expression which is a constant at compile time. Any expression
-that accesses storage, blockchain data (e.g. ``now``, ``this.balance`` or
+that accesses storage, blockchain data (e.g. ``now``, ``address(this).balance`` or
 ``block.number``) or
 execution data (``msg.value`` or ``gasleft()``) or make calls to external contracts are disallowed. Expressions
 that might have a side-effect on memory allocation are allowed, but those that
@@ -505,7 +505,7 @@ Functions can be declared ``pure`` in which case they promise not to read from o
 In addition to the list of state modifying statements explained above, the following are considered reading from the state:
 
 #. Reading from state variables.
-#. Accessing ``this.balance`` or ``<address>.balance``.
+#. Accessing ``address(this).balance`` or ``<address>.balance``.
 #. Accessing any of the members of ``block``, ``tx``, ``msg`` (with the exception of ``msg.sig`` and ``msg.data``).
 #. Calling any function not marked ``pure``.
 #. Using inline assembly that contains certain opcodes.
@@ -580,7 +580,7 @@ Like any function, the fallback function can execute complex operations as long
     but do not define a fallback function
     throw an exception, sending back the Ether (this was different
     before Solidity v0.4.0). So if you want your contract to receive Ether,
-    you have to implement a fallback function.
+    you have to implement a payable fallback function.
 
 .. warning::
     A contract without a payable fallback function can receive Ether as a recipient of a `coinbase transaction` (aka `miner block reward`)
@@ -588,11 +588,11 @@ Like any function, the fallback function can execute complex operations as long
 
     A contract cannot react to such Ether transfers and thus also cannot reject them. This is a design choice of the EVM and Solidity cannot work around it.
 
-    It also means that ``this.balance`` can be higher than the sum of some manual accounting implemented in a contract (i.e. having a counter updated in the fallback function).
+    It also means that ``address(this).balance`` can be higher than the sum of some manual accounting implemented in a contract (i.e. having a counter updated in the fallback function).
 
 ::
 
-    pragma solidity ^0.4.0;
+    pragma solidity >0.4.24;
 
     contract Test {
         // This function is called for all messages sent to
@@ -613,14 +613,13 @@ Like any function, the fallback function can execute complex operations as long
 
     contract Caller {
         function callTest(Test test) public {
-            test.call(abi.encodeWithSignature("nonExistingFunction()"));
+            address(test).call(abi.encodeWithSignature("nonExistingFunction()"));
             // results in test.x becoming == 1.
 
-            // The following will not compile, but even
-            // if someone sends ether to that contract,
+            // If someone sends ether to that contract,
             // the transaction will fail and reject the
             // Ether.
-            //test.send(2 ether);
+            address(test).send(2 ether);
         }
     }
 

docs/control-structures.rst

@@ -418,18 +418,18 @@ a message string for ``require``, but not for ``assert``.
 
 ::
 
-    pragma solidity ^0.4.22;
+    pragma solidity >0.4.24;
 
     contract Sharer {
         function sendHalf(address addr) public payable returns (uint balance) {
             require(msg.value % 2 == 0, "Even value required.");
-            uint balanceBeforeTransfer = this.balance;
+            uint balanceBeforeTransfer = address(this).balance;
             addr.transfer(msg.value / 2);
             // Since transfer throws an exception on failure and
             // cannot call back here, there should be no way for us to
             // still have half of the money.
-            assert(this.balance == balanceBeforeTransfer - msg.value / 2);
-            return this.balance;
+            assert(address(this).balance == balanceBeforeTransfer - msg.value / 2);
+            return address(this).balance;
         }
     }
 

docs/units-and-global-variables.rst

@@ -180,6 +180,10 @@ For more information, see the section on :ref:`address`.
     to make safe Ether transfers, always check the return value of ``send``, use ``transfer`` or even better:
     Use a pattern where the recipient withdraws the money.
 
+.. note::
+   Prior to version 0.5.0, Solidity allowed address members to be accessed by a contract instance, for example ``this.balance``.
+   This is now forbidden and an explicit conversion to address must be done: ``address(this).balance``.
+
 .. note::
    If storage variables are accessed via a low-level delegatecall, the storage layout of the two contracts
    must align in order for the called contract to correctly access the storage variables of the calling contract by name.

test/compilationTests/corion/ico.sol

@@ -231,7 +231,7 @@ contract ico is safeMath {
         require( ! aborted );
         require( token(tokenAddr).mint(foundationAddress, token(tokenAddr).totalSupply() * 96 / 100) );
         require( premium(premiumAddr).mint(foundationAddress, totalMint / 5000 - totalPremiumMint) );
-        require( foundationAddress.send(this.balance) );
+        require( foundationAddress.send(address(this).balance) );
         require( token(tokenAddr).closeIco() );
         require( premium(premiumAddr).closeIco() );
     }

test/compilationTests/corion/module.sol

@@ -95,8 +95,8 @@ contract module {
         if ( _balance > 0 ) {
             require( abstractModuleHandler(moduleHandlerAddress).transfer(address(this), newModuleAddress, _balance, false) );
         }
-        if ( this.balance > 0 ) {
-            require( newModuleAddress.send(this.balance) );
+        if ( address(this).balance > 0 ) {
+            require( newModuleAddress.send(address(this).balance) );
         }
         moduleStatus = status.Disconnected;
     }

test/compilationTests/corion/token.sol

@@ -73,7 +73,7 @@ contract token is safeMath, module, announcementTypes {
         if ( ! forReplace ) {
             require( db.replaceOwner(this) );
             assert( genesisAddr.length == genesisValue.length );
-            require( this.balance >= genesisAddr.length * 0.2 ether );
+            require( address(this).balance >= genesisAddr.length * 0.2 ether );
             for ( uint256 a=0 ; a<genesisAddr.length ; a++ ) {
                 genesis[genesisAddr[a]] = true;
                 require( db.increase(genesisAddr[a], genesisValue[a]) );

test/compilationTests/zeppelin/Bounty.sol

@@ -55,7 +55,7 @@ contract Bounty is PullPayment, Destructible {
     if (target.checkInvariant()) {
       throw;
     }
-    asyncSend(researcher, this.balance);
+    asyncSend(researcher, address(this).balance);
     claimed = true;
   }
 

test/compilationTests/zeppelin/LimitBalance.sol

@@ -23,7 +23,7 @@ contract LimitBalance {
    * @dev Checks if limit was reached. Case true, it throws.
    */
   modifier limitedPayable() {
-    if (this.balance > limit) {
+    if (address(this).balance > limit) {
       throw;
     }
     _;

test/compilationTests/zeppelin/crowdsale/RefundVault.sol

@@ -37,7 +37,7 @@ contract RefundVault is Ownable {
     require(state == State.Active);
     state = State.Closed;
     emit Closed();
-    wallet.transfer(this.balance);
+    wallet.transfer(address(this).balance);
   }
 
   function enableRefunds() public onlyOwner {

test/compilationTests/zeppelin/ownership/HasNoEther.sol

@@ -37,7 +37,7 @@ contract HasNoEther is Ownable {
    * @dev Transfer all Ether held by the contract to the owner.
    */
   function reclaimEther() external onlyOwner {
-    if(!owner.send(this.balance)) {
+    if(!owner.send(address(this).balance)) {
       throw;
     }
   }

test/compilationTests/zeppelin/payment/PullPayment.sol

@@ -36,7 +36,7 @@ contract PullPayment {
       throw;
     }
 
-    if (this.balance < payment) {
+    if (address(this).balance < payment) {
       throw;
     }