Foundry Nightly (2026-04-25): New ERC20 Lint and EVM Refactors

Foundry Nightly Update: Why It Matters

Foundry’s latest nightly release—tagged as nightly-973feff27f8da87423bab917f89a4f71ef7c8e69 on April 25, 2026—dropped a handful of updates that smart contract developers need to pay attention to. We’re talking new linting rules for ERC20 interfaces, EVM refactoring, and a bump to revm v38. If you’re building with Foundry, these changes could save you from subtle bugs—or break your workflow if you’re not careful.

What’s New in Foundry Nightly

Let’s dig into the commits from Foundry Releases and break down what’s landed. This isn’t just a changelog dump—I’ve pulled the key updates that impact your day-to-day as a Solidity dev.

• New ERC20 Interface Lint (#14428 by @figtracer): Foundry now flags incorrect ERC20 interface implementations. If your contract claims to implement ERC20 but misses a required function like transfer or messes up the event signature for Transfer, you’ll get a warning. This is huge for catching spec violations early.
• Block Timestamp Lint (#14431 by @stevencartavia): Another linting addition—checks for unsafe usage of block.timestamp. If you’re using it in a way that could be manipulated (yes, miners can tweak this), Foundry will yell at you.
• EVM Refactor: Remove OP EVM Wrapper (#14440 by @mablr): A cleanup in the EVM internals. The unnecessary wrapper around Optimism’s EVM implementation is gone, which should streamline execution. No direct API changes, but expect a slight performance uptick.
• Revm Bump to v38 (#14436 by @0xrusowsky): Foundry’s underlying EVM engine got updated. Check the revm changelog if you’re deep into custom opcodes—there might be subtle behavior shifts.
• Fix Nested Debug Trace Recording (#14423 by @Perico-perica46): Cheatcodes now reject nested debug trace calls. If you’ve been stacking vm.startPrank or similar in debug mode, this will error out. Clean up your test scripts.
• Gas Report Snapshot Fix (#14439 by @zerosnacks): Gas parameters sync got fixed, and the gas report snapshots are updated. If your CI relies on gas benchmarks, re-run your tests.

Here’s the thing: these linting additions are a quiet win for smart contract security. Missing an ERC20 function isn’t just a bug—it’s a potential exploit vector. For gas optimization nerds (like me), the EVM refactor and revm bump hint at tighter execution, though I’d wait for benchmarks before celebrating.

The implication for builders? Audit your ERC20 contracts with this new lint ASAP, and if you’re using cheatcodes in complex test setups, expect some friction.

Developer Impact

So, what does this mean for your workflow? Let’s break it down.

First, migration isn’t a huge lift—most of these changes are additive or internal. But if you’ve got tests with nested debug tracing, you’re gonna hit a wall. The fix is simple: flatten your test logic or split debug calls. Annoying, but doable.

Breaking changes are minimal. The cheatcode restriction is the only explicit one, and it’s more of a guardrail than a wrecking ball. New capabilities, though? Those linting rules are gold. As I’ve covered before in my smart contract security pieces, subtle interface mismatches are a recurring theme in audits. Foundry’s got your back now.

Performance-wise, the EVM wrapper removal and revm v38 update might shave off a few gas units in execution. I haven’t seen hard numbers yet (if you’ve got benchmarks, hit me up), but even a 1% improvement matters when you’re deploying at scale. For DeFi devs tracking gas costs, re-test your contracts and update your reports with the new snapshots.

And one more thing—there’s a new ignored_error_codes_from config option (#13841 by @ndavd). You can now silence specific lint warnings if they’re noise for your project. Handy if you’ve got legacy code you can’t refactor yet.

For builders, the takeaway is clear: integrate these linting rules into your CI pipeline. Check out our smart contract audit tools if you want to double down on security.

Getting Started with the Update

Ready to pull this nightly build? It’s straightforward, but there are a couple of gotchas to watch for. Here’s how to get rolling:

1. Update Foundry to the latest nightly with foundryup --version nightly-973feff27f8da87423bab917f89a4f71ef7c8e69. Verify the commit hash post-install.
2. Run forge lint on your ERC20 contracts. Look for interface mismatch warnings—fix any missing functions or incorrect signatures.
3. If you’re using block.timestamp, expect lint errors on unsafe patterns. Refactor to use a safer oracle if possible (or suppress with the new config option).
4. Test your debug scripts. Nested tracing will fail—split your calls or rework the test.
5. Re-generate gas reports if you track them. The snapshots are updated, so your old numbers are stale.

The official Foundry docs have the full linting rule details if you need to dig deeper. For Solidity-specific gotchas on ERC20, the Solidity docs are still your best friend.

Common pitfalls? Watch for overzealous linting on custom ERC20 extensions—sometimes a non-standard implementation is intentional. Use the ignore config sparingly, though. And if you’re new to Foundry, poke around our Developer Hub for more Web3 development resources.

I’ll throw in a quote from a contributor on the ERC20 lint PR: “This catches a class of bugs that’s embarrassingly common,” said @figtracer in the commit notes. Couldn’t agree more—half the hacks I’ve reviewed stem from spec drift.

Code Implications for Smart Contract Devs

Let’s get nerdy for a second. The ERC20 lint checks your contract against the standard interface. If you’ve got something like this:

solidityCopy
1contract MyToken {
2    function transfer(address to, uint256 amount) public returns (bool); // Missing event emission
3}

Foundry will flag it because there’s no Transfer event. The fix is obvious—add the event and emit it in transfer. But here’s what struck me: this lint also catches signature mismatches. Say your transfer returns uint256 instead of bool. That’s a fail too.

On the EVM side, removing the OP wrapper means less overhead for Optimism-based testing. If you’re simulating on OP Mainnet or testnets, your forge test runs might be a hair faster. No code changes needed, but keep an eye on gas costs—sync with the updated reports.

For builders, this update reinforces a truth: tooling is your first line of defense. Pair Foundry’s linting with manual audits or OpenZeppelin’s battle-tested contracts via their docs, and you’re in a solid spot. Gas optimization remains a game of inches—test every commit.

What do I think? This nightly isn’t flashy, but it’s the kind of incremental win that keeps projects alive. Deadpan aside: if your ERC20 contract still fails this lint, maybe it’s time to rethink your career. Stick with Foundry, and keep shipping.