From 45d1f599ecff7b8fe9e1943ac7bb2c8b873cab12 Mon Sep 17 00:00:00 2001
From: test <test@example.com>
Date: Fri, 2 Oct 2026 19:49:25 -0400
Subject: [PATCH] evm: execute with the prague hardfork so current solc output
 runs

The executor used shanghai, which rejects MCOPY, TLOAD and TSTORE as
invalid opcodes. Current solc emits them by default.
---
 packages/evm/CHANGELOG.md         |  6 ++++++
 packages/evm/src/executor.test.ts | 28 ++++++++++++++++++++++++++++
 packages/evm/src/executor.ts      | 12 +++++++++---
 3 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/packages/evm/CHANGELOG.md b/packages/evm/CHANGELOG.md
index 556378a727..387c70f32d 100644
--- a/packages/evm/CHANGELOG.md
+++ b/packages/evm/CHANGELOG.md
@@ -7,6 +7,12 @@ specification itself are tracked in the root
 
 ## Unreleased
 
+### Fixed
+
+- The executor now runs with the Prague hardfork instead of Shanghai, so
+  bytecode from current `solc` (which uses `MCOPY`, `TLOAD` and `TSTORE`)
+  executes.
+
 ## 0.1.0-preview.0 — 2026-09-21
 
 The version scheme changed: prerelease versions are now `preview.<n>`, and
diff --git a/packages/evm/src/executor.test.ts b/packages/evm/src/executor.test.ts
index 48fbfc131e..263f8fcb40 100644
--- a/packages/evm/src/executor.test.ts
+++ b/packages/evm/src/executor.test.ts
@@ -29,6 +29,18 @@ const returnValueCode = "602a60005260206000f3";
 //   RETURN              =>  f3
 const constructorCode = "65602a600055006000526006601af3";
 
+// mcopy: PUSH1 0x2a PUSH1 0x00 MSTORE
+//        PUSH1 0x20 PUSH1 0x00 PUSH1 0x20 MCOPY
+//        PUSH1 0x20 PUSH1 0x20 RETURN
+//   Copies a word from offset 0 to offset 0x20 and returns it.
+const mcopyCode = "602a600052" + "602060006020" + "5e" + "60206020f3";
+
+// transient: PUSH1 0x2a PUSH1 0x01 TSTORE
+//            PUSH1 0x01 TLOAD PUSH1 0x00 MSTORE
+//            PUSH1 0x20 PUSH1 0x00 RETURN
+//   Stores 42 in transient slot 1, loads it and returns it.
+const transientCode = "602a60015d" + "60015c600052" + "60206000f3";
+
 describe("Executor", () => {
   let executor: Executor;
 
@@ -131,4 +143,20 @@ describe("Executor", () => {
       expect(after).not.toEqual(before);
     });
   });
+
+  describe("cancun opcodes", () => {
+    it("executes MCOPY", async () => {
+      const result = await executor.executeCode(mcopyCode);
+      expect(result.error).toBeUndefined();
+      expect(result.success).toBe(true);
+      expect(bytesToHex(result.returnValue)).toBe("2a".padStart(64, "0"));
+    });
+
+    it("executes TSTORE and TLOAD", async () => {
+      const result = await executor.executeCode(transientCode);
+      expect(result.error).toBeUndefined();
+      expect(result.success).toBe(true);
+      expect(bytesToHex(result.returnValue)).toBe("2a".padStart(64, "0"));
+    });
+  });
 });
diff --git a/packages/evm/src/executor.ts b/packages/evm/src/executor.ts
index 6a85073cf6..810eb4b87c 100644
--- a/packages/evm/src/executor.ts
+++ b/packages/evm/src/executor.ts
@@ -8,12 +8,18 @@
 import { EVM } from "@ethereumjs/evm";
 import type { InterpreterStep } from "@ethereumjs/evm";
 import { SimpleStateManager } from "@ethereumjs/statemanager";
-import { Common, Mainnet } from "@ethereumjs/common";
+import { Common, Hardfork, Mainnet } from "@ethereumjs/common";
 import { Address, Account } from "@ethereumjs/util";
 import { hexToBytes, bytesToHex } from "ethereum-cryptography/utils";
 
 import type { TraceStep, TraceHandler } from "#trace";
 
+/**
+ * Hardfork used for execution. Current solc targets prague by default,
+ * so this must be at least cancun (MCOPY, TLOAD, TSTORE, ...).
+ */
+const hardfork = Hardfork.Prague;
+
 /**
  * Options for executing a contract call.
  */
@@ -75,7 +81,7 @@ export class Executor {
   constructor() {
     const common = new Common({
       chain: Mainnet,
-      hardfork: "shanghai",
+      hardfork,
     });
     this.stateManager = new SimpleStateManager();
     this.evm = new EVM({
@@ -299,7 +305,7 @@ export class Executor {
     this.evm = new EVM({
       common: new Common({
         chain: Mainnet,
-        hardfork: "shanghai",
+        hardfork,
       }),
       stateManager: this.stateManager,
     });