fix(sol-macro): derive builtin traits on overloaded event/error enums

[pjdurden]

Fixes alloy-rs/alloy#3856

The generated *Events / *Errors enum decided whether the #[sol(all_derives)]
builtin traits (Debug, PartialEq, Eq, Hash) could be derived by resolving
each variant's type name against the item table. Overloaded items get synthetic
_N-suffixed names (Swap_0, Swap_1, …) which don't resolve as items, so the
check hit the conservative false arm and silently dropped the derives — e.g. the
Uniswap V3 Pool (two Swap events) produced a PoolEvents enum that didn't impl
the std traits.

Compute derivability from the underlying items' parameter types (available when
building ExpandData) rather than from the synthetic variant type names. The
functions enum is unaffected (contract-level all_derives is intentionally not
propagated there).

Added a regression test with overloaded events under #[sol(all_derives)].

[Copilot]

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds support for #[sol(all_derives)] on generated *Calls / *Errors / *Events enums even when variants use overloaded/synthetic names that can’t be resolved for trait-derivability checks.

Changes:

• Add enum_derives helper to apply extra_derives / all_derives to generated enums.
• Precompute can_derive_builtin from underlying parameter types for calls/errors/events expansions.
• Add a regression test for overloaded events ensuring the generated *Events enum derives the expected builtin traits.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
crates/sol-types/tests/derives.rs	Adds regression test covering overloaded events + #[sol(all_derives)] on generated events enum.
crates/sol-macro-expander/src/expand/mod.rs	Introduces enum_derives helper to derive traits on generated enums using precomputed derivability.
crates/sol-macro-expander/src/expand/contract.rs	Computes can_derive_builtin for sets of calls/errors/events and uses enum_derives for enum generation.

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[pjdurden]

Hi @mattsse , @DaniPopes Let me know if anything is required from my side for this.

[satyakwok]

Nice — computing from the underlying param types is the cleaner direction here.

[pjdurden]

Thanks @satyakwok. Resolving the synthetic _N names back to their items was the other route I tried, but derivability only really depends on the variant param types, so computing from those skips the item-table lookup entirely and falls out the same way for the non-overloaded enums too.