ReferringToRecursiveStructureMakesRecursive
DRAFT
Observed

ReferringToRecursiveStructureMakesRecursive
Incorrect

A class referring to a recursive data structure is (indirectly) part of that recursion as well

Correct

If a class refers to a recursive data structure, it is not necessarily part of that recursion

Correction
Here is what's right.

class List {
  Node head;
}

class Node {
  Node next;
}

Class List is not part of a recursive data structure. It only refers to such a structure (via the head field).

In the class diagram (i.e., graph) for the above example, class List is not part of a cycle. Class Node, however, is part of a cycle (more specifically, has a self-loop). Thus class Node is part of a recursive data structure, a structure where nodes directly refer to nodes.

Origin
Where could this misconception come from?

The above example shows where that misconception might appear. Students believe that class List is “indirectly recursive”. However, class List is not recursive at all. Class Node is recursive.