I came across the phrase 心配いりません and from what I understand it means "Dont worry". It is formed by using the する-verb 心配 (worry) and いる (to be needed). What I don't understand is why there is no particle or something between 心配 and いる.
Does this mean that する-verbs don't necessarily require the verb する or one of its related forms? Or am I just overthinking it and a particle just being omitted?