Function rustc_typeck::check::check::detect_discriminant_duplicate

fn detect_discriminant_duplicate<'tcx>(
    tcx: TyCtxt<'tcx>,
    discrs: Vec<(VariantIdx, Discr<'tcx>)>,
    vs: &'tcx [Variant<'tcx>],
    self_span: Span
)

Part of enum check. Given the discriminants of an enum, errors if two or more discriminants are equal