[Bergmann89]

Unless GeneratorFlags::BUILD_IN_ABSOLUTE_PATHS is set, the generated code refers to build-in types and traits like String, Option or Result by their bare name. A generated type with the same name shadows them and the generated code does not compile, e.g.:

• pub type String = String; (E0391, cycle detected) for xs:string when the type postfix is empty, as reported in Please provide examples of how to resolve conflicts in type names #316
• broken Option<..> fields for an element named Option, since the element postfix is empty by default

The generator now raises GeneratorError::ShadowedBuildIn for these names, which names the affected type and points to BUILD_IN_ABSOLUTE_PATHS, instead of silently generating broken code.

Changes

• New error variant ShadowedBuildIn in the generator error (additive).
• The check lives in claim_path, next to the existing DuplicateTypeName check, and is skipped when BUILD_IN_ABSOLUTE_PATHS is set.
• New feature test shadowed_build_in: error for an element named Option, error for xs:string with an empty type postfix, and a compiled quick-xml snapshot with the flag enabled.

Schemas that generate one of these names without the flag now fail with an error instead of generating code that does not compile.

Checklist

• Tests for the change (a bug fix has a test that fails without the fix)
• Changed snapshots are regenerated with update-expectations and reviewed
• cargo fmt, cargo clippy and cargo test pass (see CONTRIBUTING.md)
• Breaking changes of the public API or the generated code are described above