SonarSource Rules
  • Products

    In-IDE

    Code Quality and Security in your IDE with SonarQube Ide

    IDE extension that lets you fix coding issues before they exist!

    Discover SonarQube for IDE

    SaaS

    Code Quality and Security in the cloud with SonarQube Cloud

    Setup is effortless and analysis is automatic for most languages

    Discover SonarQube Cloud

    Self-Hosted

    Code Quality and Security Self-Hosted with SonarQube Server

    Fast, accurate analysis; enterprise scalability

    Discover SonarQube Server
  • SecretsSecrets
  • ABAPABAP
  • AnsibleAnsible
  • ApexApex
  • AzureResourceManagerAzureResourceManager
  • CC
  • C#C#
  • C++C++
  • CloudFormationCloudFormation
  • COBOLCOBOL
  • CSSCSS
  • DartDart
  • DockerDocker
  • FlexFlex
  • GitHub ActionsGitHub Actions
  • GoGo
  • HTMLHTML
  • JavaJava
  • JavaScriptJavaScript
  • JSONJSON
  • JCLJCL
  • KotlinKotlin
  • KubernetesKubernetes
  • Objective CObjective C
  • PHPPHP
  • PL/IPL/I
  • PL/SQLPL/SQL
  • PythonPython
  • RPGRPG
  • RubyRuby
  • RustRust
  • ScalaScala
  • SwiftSwift
  • TerraformTerraform
  • TextText
  • TypeScriptTypeScript
  • T-SQLT-SQL
  • VB.NETVB.NET
  • VB6VB6
  • XMLXML
  • YAMLYAML
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: 36 rules found
suspicious
    Impact
      Clean code attribute
        1. Parameter names should match base declaration and other partial definitions

           Code Smell
        2. Methods should not have identical implementations

           Code Smell
        3. Collection elements should not be replaced unconditionally

           Bug
        4. A conditionally executed single line should be denoted by indentation

           Code Smell
        5. Conditionals should start on new lines

           Code Smell
        6. Number patterns should be regular

           Code Smell
        7. "out" and "ref" parameters should not be used

           Code Smell
        8. Unassigned members should be removed

           Code Smell
        9. "[DefaultValue]" should not be used when "[DefaultParameterValue]" is meant

           Code Smell
        10. Type should not be examined on "System.Type" instances

           Code Smell
        11. Assertion arguments should be passed in the correct order

           Code Smell
        12. "this" should not be exposed from constructors

           Code Smell
        13. Implementations should be provided for "partial" methods

           Code Smell
        14. Caller information arguments should not be provided explicitly

           Code Smell
        15. "Explicit" conversions of "foreach" loops should not be used

           Code Smell
        16. "ConfigureAwait(false)" should be used

           Code Smell
        17. Sequential tests should not check the same condition

           Code Smell
        18. "IndexOf" checks should not be for positive numbers

           Code Smell
        19. Boolean expressions should not be gratuitous

           Code Smell
        20. Conditionally executed code should be reachable

           Bug
        21. Generic exceptions should not be ignored

           Code Smell
        22. Unnecessary bit operations should not be performed

           Code Smell
        23. Methods without side effects should not have their return values ignored

           Bug
        24. Unnecessary mathematical comparisons should not be made

           Code Smell
        25. Modulus results should not be checked for direct equality

           Code Smell
        26. Loops and recursions should not be infinite

           Bug
        27. Invalid casts should be avoided

           Code Smell
        28. Two branches in a conditional structure should not have exactly the same implementation

           Code Smell
        29. Identical expressions should not be used on both sides of operators

           Bug
        30. "==" should not be used when "Equals" is overridden

           Code Smell
        31. Methods should not be empty

           Code Smell
        32. Exceptions should not be thrown in finally blocks

           Code Smell
        33. Exit methods should not be called

           Code Smell
        34. Assignments should not be made from within sub-expressions

           Code Smell
        35. Local variables should not shadow class fields or properties

           Code Smell
        36. Nested blocks of code should not be left empty

           Code Smell

        "out" and "ref" parameters should not be used

        intentionality - clear
        maintainability
        Code Smell
        • suspicious

        Why is this an issue?

        Passing a parameter by reference, which is what happens when you use the out or ref parameter modifiers, means that the method will receive a pointer to the argument, rather than the argument itself. If the argument was a value type, the method will be able to change the argument’s values. If it was a reference type, then the method receives a pointer to a pointer, which is usually not what was intended. Even when it is what was intended, this is the sort of thing that’s difficult to get right, and should be used with caution.

        This rule raises an issue when out or ref is used on a non-Optional parameter in a public method. Optional parameters are covered by S3447.

        Noncompliant code example

        public void GetReply(
                 ref MyClass input, // Noncompliant
                 out string reply)  // Noncompliant
        { ... }
        

        Compliant solution

        public string GetReply(MyClass input)
        { ... }
        
        public bool TryGetReply(MyClass input, out string reply)
        { ... }
        
        public ReplyData GetReply(MyClass input)
        { ... }
        
        internal void GetReply(ref MyClass input, out string reply)
        { ... }
        

        Exceptions

        This rule will not raise issues for:

        • non-public methods
        • methods with only 'out' parameters, name starting with "Try" and return type bool.
        • interface implementation methods
          Available In:
        • SonarQube IdeCatch issues on the fly,
          in your IDE
        • SonarQube CloudDetect issues in your GitHub, Azure DevOps Services, Bitbucket Cloud, GitLab repositories
        • SonarQube Community BuildAnalyze code in your
          on-premise CI
          Available Since
          9.1
        • SonarQube ServerAnalyze code in your
          on-premise CI
          Developer Edition
          Available Since
          9.1

        © 2008-2025 SonarSource SA. All rights reserved.

        Privacy Policy | Cookie Policy | Terms of Use