Add abi.encodeError similarly to abi.encodeCall

[Amxx]

Abstract

Using abi.encodeCall for encoding errors fails with error

Error (3509): Expected regular external function type, or external view on public function. Cannot use errors for abi.encodeCall.

It would be nice to have a abi.encodeError that works similarly to abi.encodeCall, but for custom errors.

Motivation

Both functions and error include a .selector getter that returns the bytes4 "signature". In the case of a function selector, this can be used, along with abi.encodeWithSelector to generate the bytes corresponding to a function call. Similarly, abi.encodeWithSelector can be used to encode a custom error.

abi.encodeCall is a safer alternative that verifies the type and number or arguments at compile type. While abi.encodeCall works well with functions, it does not currently support errors.

Being able to generate the bytes corresponding to custom errors can be particularly usefull for testing with Foundry.

Specification

Given a custom error

error SomeErrorName(address arg0, uint256 arg1, bytes4 arg2, bytes32 arg3);

Enable the syntax

abi.encodeError(SomeErrorName, (arg0, arg1, arg2, arg3));

that returns the same as

abi.encodeWithSelector(SomeErrorName.selector, arg0, arg1, arg2, arg3);

with the same type checking as abi.encodeCall

Backwards Compatibility

None. This is introducing a new syntax that doesn't conflict with existing ones.

[github-actions]

This issue has been marked as stale due to inactivity for the last 90 days.
It will be automatically closed in 7 days.

[github-actions]

This issue has been marked as stale due to inactivity for the last 90 days.
It will be automatically closed in 7 days.

[github-actions]

This issue has been marked as stale due to inactivity for the last 90 days.
It will be automatically closed in 7 days.

[Amxx]

still relevant