Today Illinois bonds were downgraded to 1 above junk. The article. Citation from article:

Despite the lack of a budget, Illinois has continued to cover payments due on its bonds, and, like other states, has no ability to resort to bankruptcy to escape from its debts. A downgrade to junk, though, would add further financial pressure by increasing its borrowing costs and preventing many mutual funds from buying Illinois’s securities.

If "Illinois cannot go bankruptcy", is it safe to buy its bonds and wait until they mature?

After reading your 4 answers, I learned that Illinois can default without going bankrupt. If they do that what do I (and other bond holders) do? My understanding is that without bankrupt, Illinois will owe me the money forever. Can I sue Illinois and ask Illinois to sell building, lands and rise taxes to pay me back?

Has any state in USA ever declared bond default in the past?