[Feature] FixedBytes should map to FixedBytes

[rachel-bousfield]

Component

primitives, sol-type

Describe the feature you would like

Right now the SolType impl for sol_data::FixedBytes has the RustType [u8; N].

We've worked around this in the Stylus SDK by introducing a new type, abi::FixedBytesSolType, and foresee potential special casing around this quirk.

We propose that, as is already the case with integers, sol_data::FixedBytes have the RustType alloy_primitives::FixedBytes.

We're happy to help implement this change, which should be straightforward :)

[DaniPopes]

SGTM, I'll assign you to this issue then! We'll be releasing 0.4.0 with these changes.

[prestwich]

I'm on board with this change

The main impact on users will be the change to the output type of decoding for sol types containing a bytesN, which seems fine. Can you make sure this change is propagated to the DynSolValue::FixedBytes as well, by having it wrap a FixedBytes<32> instead of a [u8;32]

[DaniPopes]

Hey @rachel-bousfield, do you still plan on working on this? Otherwise I can take over this issue

[rachel-bousfield]

Hey @DaniPopes feel free to take it -- we won't have time for the next couple of weeks but probably will after that. Happy either way and thanks!