feat(evm): add exec_return opcode

[0xLucqs]

Pull Request type

Please check the type of change your PR introduces:

• Bugfix
• Feature
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build-related changes
• Documentation content changes
• Other (please describe):

What is the current behavior?

Resolves: #301

What is the new behavior?

Does this introduce a breaking change?

• Yes
• No

[enitrat]

we have a "safe cast" that returns an error if the typecast fails

prefer something like

 let popped = self.stack.pop_n(3)?;
        let dest_offset: u32 = Into::<u256, Result<u32, EVMError>>::into((*popped[0]))?;
        let offset: u32 = Into::<u256, Result<u32, EVMError>>::into((*popped[1]))?;
        let size: u32 = Into::<u256, Result<u32, EVMError>>::into((*popped[2]))?;

[0xLucqs]

this looks very bad, a try_into seems to make more sense

[enitrat]

why do you think so?

[0xLucqs]

because it's the purpose of a try_into output an error if it fails

[enitrat]

Yes, I agree, the only problem is that the corelib trait returns an Option and not a Result<T, E>. Now that I think about it it's super weird that it was designed this way

Using a Try Into would not let us propagate an error. Or we would need to use an intermediate conversion from Option to Result.

[Eikix]

we could ask them to either transform try_into or implement ok_or which converts an option into a result in Rust

[enitrat]

I dont want to add one extra step. I would prefer implementing TryIntoErr or something like this

[enitrat]

@LucasLvy Can you implement the recommendation pls, this will likely be refactored later anyway

[enitrat]

LGTM 🔥