fn maybe_supported_error(
tcx: TyCtxt<'_>,
sub: GenericConstantTooComplexSub,
root_span: Span,
) -> Result<!, ErrorGuaranteed>
fn maybe_supported_error(
tcx: TyCtxt<'_>,
sub: GenericConstantTooComplexSub,
root_span: Span,
) -> Result<!, ErrorGuaranteed>