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C#

C# static code analysis

Unique rules to find Bugs, Vulnerabilities, Security Hotspots, and Code Smells in your C# code

  • All rules 493
  • Vulnerability46
  • Bug88
  • Security Hotspot24
  • Code Smell335

  • Quick Fix 61
Filtered: 23 rules found
unused
    Impact
      Clean code attribute
        1. Unread "private" fields should be removed

           Code Smell
        2. Empty "default" clauses should be removed

           Code Smell
        3. Method overloads with default parameter values should not overlap

           Code Smell
        4. Events should be invoked

           Code Smell
        5. Namespaces should not be empty

           Code Smell
        6. Methods should not return values that are never used

           Code Smell
        7. Redundant parentheses should not be used

           Code Smell
        8. "GC.SuppressFinalize" should not be invoked for types without destructors

           Code Smell
        9. "ThreadStatic" should not be used on non-static fields

           Bug
        10. "catch" clauses should do more than rethrow

           Code Smell
        11. Conditionally executed code should be reachable

           Bug
        12. Redundant modifiers should not be used

           Code Smell
        13. Unused type parameters should be removed

           Code Smell
        14. Test classes should contain at least one test case

           Code Smell
        15. Values should not be uselessly incremented

           Bug
        16. Related "if/else if" statements should not have the same condition

           Bug
        17. Unused assignments should be removed

           Code Smell
        18. Unused local variables should be removed

           Code Smell
        19. Sections of code should not be commented out

           Code Smell
        20. Unused method parameters should be removed

           Code Smell
        21. Unused private types or members should be removed

           Code Smell
        22. Unnecessary "using" should be removed

           Code Smell
        23. Empty statements should be removed

           Code Smell

        Unnecessary "using" should be removed

        intentionality - clear
        maintainability
        Code Smell
        Quick FixIDE quick fixes available with SonarLint
        • unused

        Why is this an issue?

        How can I fix it?

        More Info

        Unnecessary using directives refer to importing namespaces, types or creating aliases that are not used or referenced anywhere in the code.

        Although they don’t affect the runtime behavior of the application after compilation, removing them will:

        • Improve the readability and maintainability of the code.
        • Help avoid potential naming conflicts.
        • Improve the build time, as the compiler has fewer lines to read and fewer types to resolve.
        • Reduce the number of items the code editor will show for auto-completion, thereby showing fewer irrelevant suggestions.

        Starting with C# 10, it’s possible to define global usings for an entire project. They reduce the need for repetitive namespace inclusions, but can also mask which namespaces are truly necessary for the code at hand. Over-relying on them can lead to less transparent code dependencies, especially for newcomers to the project.

        Exceptions

        The rule will not raise a warning for global using directives, even if none of the types of that namespace are used in the project:

        global using System.Net.Sockets; // Compliant by exception
        

        Unnecessary using directives are ignored in ASP.NET Core projects in the following files:

        • _Imports.razor
        • _ViewImports.cshtml
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