Further, because some methods require that the argument remain unmodified during the execution, passing a collection to itself can result in an unexpected behavior.
== Noncompliant Code Example
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var list = new List<int>();
list.AddRange(list); // Noncompliant
list.Concat(list); // Noncompliant
list.Union(list); // Noncompliant; always returns list
list.Except(list); // Noncompliant; always empty
list.Intersect(list); // Noncompliant; always list