Standard ERC-721 "name" and "symbol" function error with Cancun EVM

[developer-decuple]

Description:

The standard ERC-721 functions name and symbol intended to return strings throw an "invalid opcode: MCOPY" error when compiling with the Cancun EVM, while working correctly with the Shanghai EVM.

Expected Behavior:

The name and symbol functions should return string values regardless of the target EVM version.

Environment:

Compiler version: ^0.8.20
Target EVM version: Cancun (as specified in compiler settings)
Framework/IDE: Remix
Operating System: (Not relevant to this issue)

Steps to Reproduce:

Use a standard ERC-721 contract with name and symbol functions.
Compile the contract in Remix with the Cancun EVM version selected.
Deploy the contract to a blockchain.
Attempt to call the name or symbol function. This will result in the "invalid opcode: MCOPY" error.

Additional Notes:

The same contract compiles and functions correctly when using the Shanghai EVM version.
This suggests a potential incompatibility between the generated bytecode for Cancun and the expected opcodes by the EVM.

[Amxx]

This looks like you are using version 0.8.25, which sets the target to cancun by default, and uses mcopy, but you try to run the contract on a non-cancun chain (that doesn't support this opcode).

Said otherwize, the issue is not in the compiler itself, but in the fact that you use a recent version of the compiler with an older version of the EVM.

Since you are using Remix, you should make sure that you use Remix VM (Cancun) selected. Note: it doesn't work on my machine, maybe a remix bug.

An alternative is to set the target to an older version of the EVM (shanghai or earlier)

[q9f]

this currently also happens to anyone running geth --dev because it does not have cancun support yet, unfortunately.

[mehtavishwa30]

@developer-decuple Thanks for raising this here. Howerver, as described by @Amxx and @q9f in their comments, this is not a bug in the compiler but rather an issue with Remix and Geth.

For further support, consider reporting this to the respective projects.