Disallow ambiguous conversions between number literals and bytesXX types.

docs/abi-spec.rst

@@ -444,7 +444,7 @@ For example,
     pragma solidity >0.4.24;
 
     contract Test {
-      constructor() public { b = 0x12345678901234567890123456789012; }
+      constructor() public { b = hex"12345678901234567890123456789012"; }
       event Event(uint indexed a, bytes32 b);
       event Event2(uint indexed a, bytes32 b);
       function foo(uint a) public { emit Event(a, b); }

docs/contracts.rst

@@ -114,8 +114,7 @@ This means that cyclic creation dependencies are impossible.
             returns (bool ok)
         {
             // Check some arbitrary condition.
-            address tokenAddress = msg.sender;
-            return (keccak256(abi.encodePacked(newOwner)) & 0xff) == (bytes20(tokenAddress) & 0xff);
+            return currentOwner != newOwner;
         }
     }
 
@@ -811,12 +810,12 @@ as topics. The event call above can be performed in the same way as
 
     contract C {
         function f() public payable {
-            bytes32 _id = 0x420042;
+            uint256 _id = 0x420042;
             log3(
                 bytes32(msg.value),
                 bytes32(0x50cb9fe53daa9737b786ab3646f04d0150dc50ef4e75f59509d83667ad5adb20),
                 bytes32(uint256(msg.sender)),
-                _id
+                bytes32(_id)
             );
         }
     }

docs/types.rst

@@ -773,7 +773,7 @@ Members
             // but can be treated identical to "uint8[]"
             m_byteData = data;
             m_byteData.length += 7;
-            m_byteData[3] = byte(8);
+            m_byteData[3] = 0x08;
             delete m_byteData[2];
         }