Proposal to move types and errors files to dedicated folders

[AmadiMichael]

This design doc proposes moving types and errors files out of */libraries/ and */lib/ files and into dedicated folders named */types/ and */errors/.

Issues:

• EVM Engineering: propose moving error files into an errors folder optimism#12642
• EVM Engineering: propose moving type files into a types folder optimism#12645

[smartcontracts]

We should consider how this relates to #143

I think there may be a future where errors are always defined in the contracts themselves, especially since #143 suggests having the error format be ContractName_SomeError.

[maurelian]

Agree with the principle here. There's a reason we wanted error strings to be prefixed with the contract name, and I find generic Unauthorized errors less helpful unless you're printing the trace (which requires more careful re

That said, I do like the idea of consolidating errors into a few locations, so what we could do is:

error Unauthorized(string location);

// and called as: 
revert Unauthorized(type(SomeContract).name);

// this would be nice too, but for some reason is failing for me in `chisel`: 
revert Unauthorized(type(this).name);

[smartcontracts]

Interesting, can you bring this up on #143?

[ControlCplusControlV]

For how many errors do you think we could actually consolidate like that? I do like this syntax but if its just like 3 errors or so I think it might be fine to duplicate, but will continue discussion on #143

[smartcontracts]

I generally agree here. If it's just a few errors then I don't think it's worth it. Having a single unified standard is valuable.

[AmadiMichael]

Here's a recap and conclusion of the discussion between @smartcontracts, @ControlCplusControlV and I on discord

1. Error Files: We agreed to remove error files altogether, embedding errors directly in contracts and possibly following Standardize on Custom errors #143 if the proposal is accepted. This has the advantage of also simplifying imports.
2. Type Files: For now, types files will remain as is, until the discussion for moving dispute/cannon folders into the L1 folder commences. #Issue

[AmadiMichael]

Discussed in #150. Conclusion was

• For errors: it will follow Standardize on Custom errors #143
• For types: it will remain as is (for now)