Adopt new Solidity features interfaceId, try/catch, keccak constants (#2487)

* Clean code

-  using type().interfaceId to improve readeability of ERC165 registration
- hardcoding some keccak256 that are otherwise computed at construction.

* hardcode keccak256 result

* Improve code readeability using try/catch

* Remove hardcoded hash 

tests show that solc 0.8.0 does the optimization as expected

* Use try/catch to improve readability

* ERC165Checker: Do not revert when returndata is empty + new test

* Address PR comments

* improve testing of ERC721Receiver errors

* put back comment about invalid interface id

* coverage does not support 0.8.1. Reverting back to 0.8.0

* bubble all data with length > 0 if onERC721Receive fails.

* Fix test: revert without message trigger is bubble with the default message

* using enum object to improve readability

contracts/introspection/ERC165.sol

@@ -11,11 +11,6 @@ import "./IERC165.sol";
  * their support of an interface.
  */
 abstract contract ERC165 is IERC165 {
-    /*
-     * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
-     */
-    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
-
     /**
      * @dev Mapping of interface ids to whether or not it's supported.
      */
@@ -24,7 +19,7 @@ abstract contract ERC165 is IERC165 {
     constructor () {
         // Derived contracts need only register support for their own interfaces,
         // we register support for ERC165 itself here
-        _registerInterface(_INTERFACE_ID_ERC165);
+        _registerInterface(type(IERC165).interfaceId);
     }
 
     /**

contracts/introspection/ERC165Checker.sol

@@ -2,6 +2,8 @@
 
 pragma solidity ^0.8.0;
 
+import "./IERC165.sol";
+
 /**
  * @dev Library used to query support of an interface declared via {IERC165}.
  *
@@ -13,18 +15,13 @@ library ERC165Checker {
     // As per the EIP-165 spec, no interface should ever match 0xffffffff
     bytes4 private constant _INTERFACE_ID_INVALID = 0xffffffff;
 
-    /*
-     * bytes4(keccak256('supportsInterface(bytes4)')) == 0x01ffc9a7
-     */
-    bytes4 private constant _INTERFACE_ID_ERC165 = 0x01ffc9a7;
-
     /**
      * @dev Returns true if `account` supports the {IERC165} interface,
      */
     function supportsERC165(address account) internal view returns (bool) {
         // Any contract that implements ERC165 must explicitly indicate support of
         // InterfaceId_ERC165 and explicitly indicate non-support of InterfaceId_Invalid
-        return _supportsERC165Interface(account, _INTERFACE_ID_ERC165) &&
+        return _supportsERC165Interface(account, type(IERC165).interfaceId) &&
             !_supportsERC165Interface(account, _INTERFACE_ID_INVALID);
     }
 
@@ -101,29 +98,9 @@ library ERC165Checker {
      * Interface identification is specified in ERC-165.
      */
     function _supportsERC165Interface(address account, bytes4 interfaceId) private view returns (bool) {
-        // success determines whether the staticcall succeeded and result determines
-        // whether the contract at account indicates support of _interfaceId
-        (bool success, bool result) = _callERC165SupportsInterface(account, interfaceId);
-
-        return (success && result);
-    }
-
-    /**
-     * @notice Calls the function with selector 0x01ffc9a7 (ERC165) and suppresses throw
-     * @param account The address of the contract to query for support of an interface
-     * @param interfaceId The interface identifier, as specified in ERC-165
-     * @return success true if the STATICCALL succeeded, false otherwise
-     * @return result true if the STATICCALL succeeded and the contract at account
-     * indicates support of the interface with identifier interfaceId, false otherwise
-     */
-    function _callERC165SupportsInterface(address account, bytes4 interfaceId)
-        private
-        view
-        returns (bool, bool)
-    {
-        bytes memory encodedParams = abi.encodeWithSelector(_INTERFACE_ID_ERC165, interfaceId);
+        bytes memory encodedParams = abi.encodeWithSelector(IERC165(account).supportsInterface.selector, interfaceId);
         (bool success, bytes memory result) = account.staticcall{ gas: 30000 }(encodedParams);
-        if (result.length < 32) return (false, false);
-        return (success, abi.decode(result, (bool)));
+        if (result.length < 32) return false;
+        return success && abi.decode(result, (bool));
     }
 }

contracts/introspection/ERC1820Implementer.sol

@@ -13,7 +13,7 @@ import "./IERC1820Implementer.sol";
  * registration to be complete.
  */
 contract ERC1820Implementer is IERC1820Implementer {
-    bytes32 constant private _ERC1820_ACCEPT_MAGIC = keccak256(abi.encodePacked("ERC1820_ACCEPT_MAGIC"));
+    bytes32 private constant _ERC1820_ACCEPT_MAGIC = keccak256("ERC1820_ACCEPT_MAGIC");
 
     mapping(bytes32 => mapping(address => bool)) private _supportedInterfaces;