I frequently invoke the quickfix "Create field for parameter 'foo'" when the field already exists. Idea detects this only later on, and asks "Use existing field '_foo'?"
While this is nice, it is too heavyweight (one dialog and two keystrokes too much).
Can't Idea detect the field right from the start and offer an additional quickfix "Assign Parameter 'foo' to field '_foo'?
Is this inspection from the Inspections Plugin? In that case I would try to implement it myself.