CodeQL documentation

Class has same name as super class

ID: cs/class-name-matches-base-class
Kind: problem
Security severity: 
Severity: recommendation
Precision: high
   - maintainability
   - readability
   - naming
Query suites:
   - csharp-security-and-quality.qls

Click to see the query in the CodeQL repository

This rule identifies a class that has the same name as a class it extends. This is likely to cause confusion.


Change the name of the subclass to make it more clear what its purpose is. It is normally possible to express how it is different to a superclass.


In this example references to ArrayList later on in the Players class could be confusing.

class Players
    private ArrayList playerList;
    class ArrayList : System.Collections.ArrayList
        public String GetBestThree()
            return "1st: " + this[0] + "\n 2nd:" + this[1] + "\n 3rd:" + this[2];

Fixing by Using a More Descriptive Name

The example could be easily fixed by changing the Players.ArrayList class name to Players.PlayerList. This is more descriptive and it avoids confusion with the ArrayList class from Collections.


  • Robert C. Martin, Clean Code - A handbook of agile software craftsmanship, §17.N4. Prentice Hall, 2008.

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