fn parse_sidecar_info(
input: &DeriveInput,
class_system: ClassSystem,
) -> Result<SidecarInfo>Expand description
Parse struct fields for sidecar information.
Iterates over all fields, identifying #[r_data] markers. Fields with
RSidecar type are tracked as selector markers (at most one allowed);
all other #[r_data] fields become SidecarSlot entries with their
slot kind inferred from the field type.
Returns Err if more than one RSidecar field is found.