Function query_ensure_error_guaranteed 

pub(crate) fn query_ensure_error_guaranteed<'tcx, Cache, T>(
    tcx: TyCtxt<'tcx>,
    execute_query: fn(TyCtxt<'tcx>, Span, Cache::Key, QueryMode) -> Option<Cache::Value>,
    query_cache: &Cache,
    key: Cache::Key,
    check_cache: bool,
) -> Result<(), ErrorGuaranteed>
where
    Cache: QueryCache<Value = Erase<Result<T, ErrorGuaranteed>>>,
    Result<T, ErrorGuaranteed>: EraseType,

Shared implementation of tcx.ensure_ok().$query(..) for queries that have the return_result_from_ensure_ok modifier.