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Code analysis updates for .NET 10 GA #49662

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66 changes: 37 additions & 29 deletions docs/fundamentals/code-analysis/overview.md
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title: Code analysis in .NET
titleSuffix: ""
description: Learn about source code analysis in the .NET SDK.
ms.date: 09/30/2025
ms.date: 11/05/2025
ms.topic: overview
ms.custom: updateeachrelease
helpviewer_keywords:
Expand All @@ -24,6 +24,41 @@ If rule violations are found by an analyzer, they're reported as a suggestion, w

### Enabled rules

# [.NET 10](#tab/net-10)

The following rules are enabled, by default, as errors or warnings in .NET 10. Additional rules are enabled as suggestions.

| Diagnostic ID | Category | Severity | Version added | Description |
|-----------------------------------|------------------|----------|---------------|---------------------------------|
| [CA1416](quality-rules/ca1416.md) | Interoperability | Warning | .NET 5 | Validate platform compatibility |
| [CA1417](quality-rules/ca1417.md) | Interoperability | Warning | .NET 5 | Do not use `OutAttribute` on string parameters for P/Invokes |
| [CA1418](quality-rules/ca1418.md) | Interoperability | Warning | .NET 6 | Use valid platform string |
| [CA1420](quality-rules/ca1420.md) | Interoperability | Warning | .NET 7 | Using features that require runtime marshalling when it's disabled will result in run-time exceptions |
| [CA1422](quality-rules/ca1422.md) | Interoperability | Warning | .NET 7 | Validate platform compatibility |
| [CA1831](quality-rules/ca1831.md) | Performance | Warning | .NET 5 | Use `AsSpan` instead of range-based indexers for string when appropriate |
| [CA1856](quality-rules/ca1856.md) | Performance | Error | .NET 8 | Incorrect usage of `ConstantExpected` attribute |
| [CA1857](quality-rules/ca1857.md) | Performance | Warning | .NET 8 | A constant is expected for the parameter |
| [CA2013](quality-rules/ca2013.md) | Reliability | Warning | .NET 5 | Do not use `ReferenceEquals` with value types |
| [CA2014](quality-rules/ca2014.md) | Reliability | Warning | .NET 5 | Do not use `stackalloc` in loops |
| [CA2015](quality-rules/ca2015.md) | Reliability | Warning | .NET 5 | Do not define finalizers for types derived from <xref:System.Buffers.MemoryManager%601> |
| [CA2017](quality-rules/ca2017.md) | Reliability | Warning | .NET 6 | Parameter count mismatch |
| [CA2018](quality-rules/ca2018.md) | Reliability | Warning | .NET 6 | The `count` argument to `Buffer.BlockCopy` should specify the number of bytes to copy |
| [CA2021](quality-rules/ca2021.md) | Reliability | Warning | .NET 8 | Do not call `Enumerable.Cast<T>` or `Enumerable.OfType<T>` with incompatible types |
| [CA2022](quality-rules/ca2022.md) | Reliability | Warning | .NET 9 | Avoid inexact read with `Stream.Read` |
| [CA2023](quality-rules/ca2023.md) | Reliability | Warning | .NET 10 | Invalid braces in message template |
| [CA2200](quality-rules/ca2200.md) | Usage | Warning | .NET 5 | Rethrow to preserve stack details |
| [CA2247](quality-rules/ca2247.md) | Usage | Warning | .NET 5 | Argument passed to `TaskCompletionSource` constructor should be <xref:System.Threading.Tasks.TaskCreationOptions> enum instead of <xref:System.Threading.Tasks.TaskContinuationOptions> |
| [CA2252](quality-rules/ca2252.md) | Usage | Error | .NET 6 | Opt in to preview features |
| [CA2255](quality-rules/ca2255.md) | Usage | Warning | .NET 6 | The `ModuleInitializer` attribute should not be used in libraries |
| [CA2256](quality-rules/ca2256.md) | Usage | Warning | .NET 6 | All members declared in parent interfaces must have an implementation in a `DynamicInterfaceCastableImplementation`-attributed interface |
| [CA2257](quality-rules/ca2257.md) | Usage | Warning | .NET 6 | Members defined on an interface with the `DynamicInterfaceCastableImplementationAttribute` should be `static` |
| [CA2258](quality-rules/ca2258.md) | Usage | Warning | .NET 6 | Providing a `DynamicInterfaceCastableImplementation` interface in Visual Basic is unsupported |
| [CA2259](quality-rules/ca2259.md) | Usage | Warning | .NET 7 | `ThreadStatic` only affects static fields |
| [CA2260](quality-rules/ca2260.md) | Usage | Warning | .NET 7 | Use correct type parameter |
| [CA2261](quality-rules/ca2261.md) | Usage | Warning | .NET 8 | Do not use `ConfigureAwaitOptions.SuppressThrowing` with `Task<TResult>` |
| [CA2264](quality-rules/ca2264.md) | Usage | Warning | .NET 9 | Do not pass a non-nullable value to `ArgumentNullException.ThrowIfNull` |
| [CA2265](quality-rules/ca2265.md) | Usage | Warning | .NET 9 | Do not compare `Span<T>` to `null` or `default` |

# [.NET 9](#tab/net-9)

The following rules are enabled, by default, as errors or warnings in .NET 9. Additional rules are enabled as suggestions.
Expand Down Expand Up @@ -89,38 +124,11 @@ The following rules are enabled, by default, as errors or warnings in .NET 8. Ad
| [CA2260](quality-rules/ca2260.md) | Usage | Warning | .NET 7 | Use correct type parameter |
| [CA2261](quality-rules/ca2261.md) | Usage | Warning | .NET 8 | Do not use `ConfigureAwaitOptions.SuppressThrowing` with `Task<TResult>` |

# [.NET 7](#tab/net-7)

The following rules are enabled, by default, as errors or warnings in .NET 7. Additional rules are enabled as suggestions.

| Diagnostic ID | Category | Severity | Description |
| - | - | - | - |
| [CA1416](quality-rules/ca1416.md) | Interoperability | Warning | Validate platform compatibility |
| [CA1417](quality-rules/ca1417.md) | Interoperability | Warning | Do not use `OutAttribute` on string parameters for P/Invokes |
| [CA1418](quality-rules/ca1418.md) | Interoperability | Warning | Use valid platform string |
| [CA1420](quality-rules/ca1420.md) | Interoperability | Warning | Using features that require runtime marshalling when it's disabled will result in run-time exceptions |
| [CA1422](quality-rules/ca1422.md) | Interoperability | Warning | Validate platform compatibility |
| [CA1831](quality-rules/ca1831.md) | Performance | Warning | Use `AsSpan` instead of range-based indexers for string when appropriate |
| [CA2013](quality-rules/ca2013.md) | Reliability | Warning | Do not use `ReferenceEquals` with value types |
| [CA2014](quality-rules/ca2014.md) | Reliability | Warning | Do not use `stackalloc` in loops |
| [CA2015](quality-rules/ca2015.md) | Reliability | Warning | Do not define finalizers for types derived from <xref:System.Buffers.MemoryManager%601> |
| [CA2017](quality-rules/ca2017.md) | Reliability | Warning | Parameter count mismatch |
| [CA2018](quality-rules/ca2018.md) | Reliability | Warning | The `count` argument to `Buffer.BlockCopy` should specify the number of bytes to copy |
| [CA2200](quality-rules/ca2200.md) | Usage | Warning | Rethrow to preserve stack details |
| [CA2247](quality-rules/ca2247.md) | Usage | Warning | Argument passed to `TaskCompletionSource` constructor should be <xref:System.Threading.Tasks.TaskCreationOptions> enum instead of <xref:System.Threading.Tasks.TaskContinuationOptions> |
| [CA2252](quality-rules/ca2252.md) | Usage | Error | Opt in to preview features |
| [CA2255](quality-rules/ca2255.md) | Usage | Warning | The `ModuleInitializer` attribute should not be used in libraries |
| [CA2256](quality-rules/ca2256.md) | Usage | Warning | All members declared in parent interfaces must have an implementation in a `DynamicInterfaceCastableImplementation`-attributed interface |
| [CA2257](quality-rules/ca2257.md) | Usage | Warning | Members defined on an interface with the `DynamicInterfaceCastableImplementationAttribute` should be `static` |
| [CA2258](quality-rules/ca2258.md) | Usage | Warning | Providing a `DynamicInterfaceCastableImplementation` interface in Visual Basic is unsupported |
| [CA2259](quality-rules/ca2259.md) | Usage | Warning | `ThreadStatic` only affects static fields |
| [CA2260](quality-rules/ca2260.md) | Usage | Warning | Use correct type parameter |

---

You can change the severity of these rules to disable them or elevate them to errors. You can also [enable more rules](#enable-additional-rules).

- For a list of rules that are included with each .NET SDK version, see [Analyzer releases](https://github.com/dotnet/roslyn-analyzers/blob/main/src/NetAnalyzers/Core/AnalyzerReleases.Shipped.md).
- For a list of rules that are included with each .NET SDK version, see [Analyzer releases](https://github.com/dotnet/sdk/blob/main/src/Microsoft.CodeAnalysis.NetAnalyzers/src/Microsoft.CodeAnalysis.NetAnalyzers/AnalyzerReleases.Shipped.md).
- For a list of all the code quality rules, see [Code quality rules](quality-rules/index.md).

### Enable additional rules
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| **Title** | Do not declare static members on generic types |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Types that own disposable fields should be disposable |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking - If the type is not visible outside the assembly.<br/><br/>Breaking - If the type is visible outside the assembly. |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Do not expose generic lists |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Use generic event handler instances |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Avoid excessive parameters on generic types |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Enums should have zero value |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking - When you're prompted to add a `None` value to a non-flag enumeration. Breaking - When you're prompted to rename or remove any enumeration values. |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Collections should implement generic interface |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Abstract types should not have public constructors |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Mark assemblies with CLSCompliantAttribute |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Mark assemblies with AssemblyVersionAttribute |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | As suggestion |
| **Enabled by default in .NET 10** | As suggestion |

## Cause

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| **Title** | Mark assemblies with ComVisibleAttribute |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Mark attributes with AttributeUsageAttribute |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | As suggestion |
| **Enabled by default in .NET 10** | As suggestion |

## Cause

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| **Title** | Define accessors for attribute arguments |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Avoid out parameters |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Use properties where appropriate |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Mark enums with FlagsAttribute |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Enum storage should be Int32 |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Use events where appropriate |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Do not catch general exception types |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Implement standard exception constructors |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Interface methods should be callable by child types |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Nested types should not be visible |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Override methods on comparable types |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Avoid empty interfaces |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Breaking |
| **Enabled by default in .NET 9** | No |
| **Enabled by default in .NET 10** | No |

## Cause

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| **Title** | Provide ObsoleteAttribute message |
| **Category** | [Design](design-warnings.md) |
| **Fix is breaking or non-breaking** | Non-breaking |
| **Enabled by default in .NET 9** | As suggestion |
| **Enabled by default in .NET 10** | As suggestion |

## Cause

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