From e151f56924ac54bffc889e447f7b8fef715e6cf8 Mon Sep 17 00:00:00 2001
From: aitbc1 <aitbc1-agent@keisanki.net>
Date: Fri, 27 Mar 2026 23:18:33 +0100
Subject: [PATCH] fix: update EVM version to cancun for mcopy instruction
 support
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HARDHAT EVM FIX: Resolve mcopy instruction compatibility issue

Issue Fixed:
❌ TypeError: The mcopy instruction is only available for Cancun-compatible VMs
❌ Compiling for shanghai EVM version
❌ OpenZeppelin v5.0.2 using mcopy opcode
❌ HH600 compilation failure

Root Cause:
- mcopy instruction requires Cancun EVM version or later
- Previous EVM version was shanghai (doesn't support mcopy)
- OpenZeppelin v5.0.2 uses mcopy for gas optimization
- EVM version too old for mcopy instruction

Solution Applied:
✅ Updated evmVersion to cancun in Hardhat config
✅ Cancun EVM supports mcopy and other new opcodes
✅ Maintains Solidity 0.8.25 compiler version
✅ Preserves optimizer settings for gas efficiency

Configuration Changes:
- evmVersion: cancun (supports mcopy)
- version: 0.8.25 (latest features)
- optimizer: enabled with 200 runs
- Compatible with OpenZeppelin v5.0.2

Impact:
- OpenZeppelin contracts now compile successfully
- mcopy instruction is supported
- No more HH600 compilation errors
- Modern EVM features available
- Gas optimizations from OpenZeppelin work
- Cancun EVM features enabled

This resolves the exact mcopy compatibility issue that was
preventing Hardhat from compiling contracts with OpenZeppelin v5.0.2.
---
 packages/solidity/aitbc-token/hardhat.config.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/solidity/aitbc-token/hardhat.config.ts b/packages/solidity/aitbc-token/hardhat.config.ts
index 9372f28a..bfc0fbb4 100644
--- a/packages/solidity/aitbc-token/hardhat.config.ts
+++ b/packages/solidity/aitbc-token/hardhat.config.ts
@@ -9,7 +9,7 @@ const config: HardhatUserConfig = {
         enabled: true,
         runs: 200
       },
-      evmVersion: "shanghai"
+      evmVersion: "cancun"
     }
   },
   paths: {