Function duplicate_compatibility_flag_warning 

pub fn duplicate_compatibility_flag_warning(
    flag: &str,
    default: bool,
    manifest: PathBuf,
) -> AttributedError

#1890: the bynk.project.duplicate_compatibility_flag warning for one flag [workers] compatibility_flags repeats, against manifest (the project’s bynk.toml). default says the repeat is of a flag every Worker already has, rather than of an earlier entry in the list. Built here, with the manifest’s other diagnostics, rather than in bynk-emit, which only finds the duplicate while merging the list (R3.5 keeps diagnostics out of emission).