Fix nightly clippy collapsible_match errors in codegen

[Copilot]

Nightly Rust clippy now enforces collapsible_match, causing 4 compile errors in codegen/src/v1/dto.rs that break CI.

Changes

Each fix keeps one match arm per rust::Type. The 4 sites in dto.rs are addressed as follows:

• Struct in can_derive_serde: Inverted the condition so the "pass" case is in the if-body and the early exit is in else:

  rust::Type::Struct(s) => {
      if can_derive_serde(s, rust_types) {
          // pass
      } else {
          return false;
      }
  }

• Provided in can_derive_default: Eliminated the nested if entirely with a single-expression return:

  rust::Type::Provided(ty) => {
      // CachedTags has a trivial Default; other Provided types fall through
      // to the field.default_value check below
      return ty.name == "CachedTags" || field.default_value.as_ref().is_some_and(is_rust_default);
  }

• Alias in ignore_empty_strings: Applied De Morgan's law to invert the compound condition, placing "pass" in the if-body and the action in else (the compound || avoids triggering clippy::if_not_else):

  rust::Type::Alias(field_ty) => {
      if !field.option_type || field_ty.type_ != "String" {
          // pass
      } else {
          g!("if self.{}.as_deref() == Some(\"\") {{", field.name);
          // ...
      }
  }

• StrEnum in ignore_empty_strings: The simple boolean condition field.option_type cannot be inverted without triggering clippy::if_not_else. Added #[allow(clippy::collapsible_match)] to the containing codegen_dto_ext function as a targeted workaround.

Semantics are unchanged across all 4 sites.

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[Copilot]

Pull request overview

Updates the Rust code generator to satisfy newer nightly Clippy collapsible_match linting by rewriting nested if checks inside match arms as match guards, keeping the generated behavior the same while unblocking CI.

Changes:

• Refactor can_derive_serde to use guarded match arms for recursive Struct checks.
• Refactor can_derive_default to use a guarded match arm for the CachedTags special-case.
• Refactor DtoExt::ignore_empty_strings codegen to use guarded match arms for Alias(String) and optional StrEnum handling.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[Nugine]

@copilot Work around the lint by

else {
// pass
}

Keep each match arm corresponding to a rust::Type.

[Copilot]

@copilot Work around the lint by

else {

...

Done in 399e232. The else { // pass } approach unfortunately doesn't work: nightly clippy treats comment-only else bodies as empty and still fires collapsible_match, and redundant_else fires when the if-body is an early exit.

Each case keeps one arm per rust::Type, fixed as follows:

• Struct (can_derive_serde): inverted condition — if can_derive_serde { // pass } else { return false; }
• Provided (can_derive_default): eliminated the if entirely — return ty.name == "CachedTags" || field.default_value...
• Alias (ignore_empty_strings): De Morgan's inversion — if !field.option_type || field_ty.type_ != "String" { // pass } else { g!()... } (compound || avoids if_not_else)
• StrEnum (ignore_empty_strings): #[allow(clippy::collapsible_match)] on codegen_dto_ext — simple boolean can't be inverted without triggering if_not_else