There is a difference between filing Bankruptcy and receiving a Bankruptcy Discharge. Although some taxes can be eliminated through Chapter 7 Bankruptcy, which taxes involves a complicated answer. I will try to simplify.
Are the taxes recent, such as within the past 4 years? Probably can't eliminate them in Bankruptcy.
Were any required returns filed on time? If not, probably can't eliminate them in Bankruptcy.
Were the taxes imposed due to an audit or some kind of legal action? If so, probably can't eliminate them in Bankruptcy.
Was a tax lien filed? Probably can't eliminate the taxes in Bankruptcy.
Since you say you did not file, it doesn't look very good to be able to eliminate taxes in Bankruptcy.
Good luck anyway!
I'm not exactly clear on what you mean in your first sentence. But in general to discharge your income tax (or, in a Chapter 13 bankruptcy, to pay less than 100% of it), the tax returns must have been filed either on time or at least 2 years before your bankruptcy case is filed. Also, there must not have been any willful attempt to evade or defeat the tax or by filing a fraudulent return. Hope that helps.