Adds support for the EVM version "Paris".

Deprecates `block.difficulty` and disallow `difficulty()` in inline assembly for EVM versions >= paris.
The change is due to the renaming introduced by EIP-4399 (see: https://eips.ethereum.org/EIPS/eip-4399).
Introduces `block.prevrandao` in Solidity and `prevrandao()` in inline assembly for EVM versions >= paris.

Co-authored-by: Alex Beregszaszi <alex@rtfs.hu>
Co-authored-by: Daniel <daniel@ekpyron.org>
Co-authored-by: matheusaaguiar <95899911+matheusaaguiar@users.noreply.github.com>
Co-authored-by: Nikola Matić <nikola.matic@ethereum.org>

docs/cheatsheet.rst

@@ -8,7 +8,7 @@ Order of Precedence of Operators
 ================================
 .. include:: types/operator-precedence-table.rst
 
-.. index:: assert, block, coinbase, difficulty, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, gas price, origin, revert, require, keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, codehash, send
+.. index:: assert, block, coinbase, difficulty, prevrandao, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, gas price, origin, revert, require, keccak256, ripemd160, sha256, ecrecover, addmod, mulmod, cryptography, this, super, selfdestruct, balance, codehash, send
 
 Global Variables
 ================
@@ -32,9 +32,10 @@ Global Variables
 - ``block.basefee`` (``uint``): current block's base fee (`EIP-3198 <https://eips.ethereum.org/EIPS/eip-3198>`_ and `EIP-1559 <https://eips.ethereum.org/EIPS/eip-1559>`_)
 - ``block.chainid`` (``uint``): current chain id
 - ``block.coinbase`` (``address payable``): current block miner's address
-- ``block.difficulty`` (``uint``): current block difficulty
+- ``block.difficulty`` (``uint``): current block difficulty (``EVM < Paris``). For other EVM versions it behaves as a deprecated alias for ``block.prevrandao`` that will be removed in the next breaking release
 - ``block.gaslimit`` (``uint``): current block gaslimit
 - ``block.number`` (``uint``): current block number
+- ``block.prevrandao`` (``uint``): random number provided by the beacon chain (``EVM >= Paris``) (see `EIP-4399 <https://eips.ethereum.org/EIPS/eip-4399>`_ )
 - ``block.timestamp`` (``uint``): current block timestamp in seconds since Unix epoch
 - ``gasleft() returns (uint256)``: remaining gas
 - ``msg.data`` (``bytes``): complete calldata

docs/grammar/SolidityLexer.g4

@@ -291,8 +291,8 @@ YulEVMBuiltin:
 	| 'returndatacopy' | 'extcodehash' | 'create' | 'create2' | 'call' | 'callcode'
 	| 'delegatecall' | 'staticcall' | 'return' | 'revert' | 'selfdestruct' | 'invalid'
 	| 'log0' | 'log1' | 'log2' | 'log3' | 'log4' | 'chainid' | 'origin' | 'gasprice'
-	| 'blockhash' | 'coinbase' | 'timestamp' | 'number' | 'difficulty' | 'gaslimit'
-	| 'basefee';
+	| 'blockhash' | 'coinbase' | 'timestamp' | 'number' | 'difficulty' | 'prevrandao'
+	| 'gaslimit' | 'basefee';
 
 YulLBrace: '{' -> pushMode(YulMode);
 YulRBrace: '}' -> popMode;

docs/units-and-global-variables.rst

@@ -65,7 +65,7 @@ There are special variables and functions which always exist in the global
 namespace and are mainly used to provide information about the blockchain
 or are general-use utility functions.
 
-.. index:: abi, block, coinbase, difficulty, encode, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, gas price, origin
+.. index:: abi, block, coinbase, difficulty, prevrandao, encode, number, block;number, timestamp, block;timestamp, msg, data, gas, sender, value, gas price, origin
 
 
 Block and Transaction Properties
@@ -75,9 +75,10 @@ Block and Transaction Properties
 - ``block.basefee`` (``uint``): current block's base fee (`EIP-3198 <https://eips.ethereum.org/EIPS/eip-3198>`_ and `EIP-1559 <https://eips.ethereum.org/EIPS/eip-1559>`_)
 - ``block.chainid`` (``uint``): current chain id
 - ``block.coinbase`` (``address payable``): current block miner's address
-- ``block.difficulty`` (``uint``): current block difficulty
+- ``block.difficulty`` (``uint``): current block difficulty (``EVM < Paris``). For other EVM versions it behaves as a deprecated alias for ``block.prevrandao`` (`EIP-4399 <https://eips.ethereum.org/EIPS/eip-4399>`_ )
 - ``block.gaslimit`` (``uint``): current block gaslimit
 - ``block.number`` (``uint``): current block number
+- ``block.prevrandao`` (``uint``): random number provided by the beacon chain (``EVM >= Paris``)
 - ``block.timestamp`` (``uint``): current block timestamp as seconds since unix epoch
 - ``gasleft() returns (uint256)``: remaining gas
 - ``msg.data`` (``bytes calldata``): complete calldata
@@ -394,4 +395,4 @@ These keywords are reserved in Solidity. They might become part of the syntax in
 ``define``, ``final``, ``implements``, ``in``, ``inline``, ``let``, ``macro``, ``match``,
 ``mutable``, ``null``, ``of``, ``partial``, ``promise``, ``reference``, ``relocatable``,
 ``sealed``, ``sizeof``, ``static``, ``supports``, ``switch``, ``typedef``, ``typeof``,
-``var``.
+``var``.

docs/yul.rst

@@ -751,8 +751,8 @@ This document does not want to be a full description of the Ethereum virtual mac
 Please refer to a different document if you are interested in the precise semantics.
 
 Opcodes marked with ``-`` do not return a result and all others return exactly one value.
-Opcodes marked with ``F``, ``H``, ``B``, ``C``, ``I`` and ``L`` are present since Frontier, Homestead,
-Byzantium, Constantinople, Istanbul or London respectively.
+Opcodes marked with ``F``, ``H``, ``B``, ``C``, ``I``, ``L`` and ``P`` are present since Frontier,
+Homestead, Byzantium, Constantinople, Istanbul, London or Paris respectively.
 
 In the following, ``mem[a...b)`` signifies the bytes of memory starting at position ``a`` up to
 but not including position ``b`` and ``storage[p]`` signifies the storage contents at slot ``p``.
@@ -931,6 +931,8 @@ the ``dup`` and ``swap`` instructions as well as ``jump`` instructions, labels a
 +-------------------------+-----+---+-----------------------------------------------------------------+
 | difficulty()            |     | F | difficulty of the current block (see note below)                |
 +-------------------------+-----+---+-----------------------------------------------------------------+
+| prevrandao()            |     | P | randomness provided by the beacon chain (see note below)        |
++-------------------------+-----+---+-----------------------------------------------------------------+
 | gaslimit()              |     | F | block gas limit of the current block                            |
 +-------------------------+-----+---+-----------------------------------------------------------------+
 
@@ -945,8 +947,10 @@ the ``dup`` and ``swap`` instructions as well as ``jump`` instructions, labels a
   The remaining bytes will retain their values as of before the call.
 
 .. note::
-  With the Paris network upgrade the semantics of ``difficulty`` have been changed.
-  It returns the value of ``prevrandao``, which is a 256-bit value, whereas the highest recorded
+  The `difficulty()` instruction is disallowed in EVM version >= Paris.
+  With the Paris network upgrade the semantics of the instruction that was previously called
+  ``difficulty`` have been changed and the instruction was renamed to ``prevrandao``.
+  It can now return arbitrary values in the full 256-bit range, whereas the highest recorded
   difficulty value within Ethash was ~54 bits.
   This change is described in `EIP-4399 <https://eips.ethereum.org/EIPS/eip-4399>`_.
   Please note that irrelevant to which EVM version is selected in the compiler, the semantics of