Can I drink 1L of Cola Zero per 2 days and be healthy?

Some sources say Cola Zero is still dangerous, some sources say the opposite statement.

I think: if Cola Zero is dangerous - the Coca Cola company would have already got a lot of lawsuits. But there is no one.

Is there any really trustworthy study about harmful effects for health with long use of Cola Zero?

List of possible issues by some news sources:
1. leaching of calcium
2. violation of the pancreas
3. violation of the liver
4. increased risk of a heart attack
5. increased risk of dementia
6. depression

If every component of Cola Zero is safe - can the sum of components be dangerous?