foundry: Arbitrum fork can't read l2 block number

Component

Forge, Anvil

Have you ensured that all of these are up to date?

• Foundry
• Foundryup

What version of Foundry are you on?

forge 0.2.0 (1caa0fa 2023-05-30T00:11:10.062347000Z)

What command(s) is the bug in?

forge test --mt testGetArbL2BlockNumber -vvvv

Operating System

macOS (Apple Silicon)

Describe the bug

Since block.number on arbitrum is block number on l1, arbitrum has a precompiled address (0x64) to reflect l2 address. Call address(0x64) arbBlockNumber to get l2 block number.

interface ArbSys {
    /**
     * @notice Get Arbitrum block number (distinct from L1 block number; Arbitrum genesis block has block number 0)
     * @return block number as int
     */
    function arbBlockNumber() external view returns (uint);
}

Create arbitrum fork and call 0x64 with arbBlockNumber(), it wil revert with "EvmError: InvalidFEOpcode". I think it’s just because the foundry evm doesn’t fulfill the precompile contract function, but there should be a way to get l2 block number on arbitrum fork. Fulfill it to compatible with arbitrum official implemtation would be great.

A minimal test to reproduce it

interface ArbSys {
    /**
     * @notice Get Arbitrum block number (distinct from L1 block number; Arbitrum genesis block has block number 0)
     * @return block number as int
     */
    function arbBlockNumber() external view returns (uint);
}

contract ArbL2NumberTest is Test {
    function testGetArbL2BlockNumber() public {
        // <https://arbiscan.io/block/75219831>
        vm.createSelectFork("https://rpc.ankr.com/arbitrum", 75219831);

        ArbSys(address(0x64)).arbBlockNumber();
    }
}