Add documentation for CA2255 (new in .NET 6) (#27096)

* Add documentation for CA2255 (new in .NET 6)

* Address pr feedback

docs/fundamentals/code-analysis/overview.md

@@ -45,7 +45,7 @@ The following rules are enabled, by default, in .NET 6.
 | [CA2200](quality-rules/ca2200.md) | Usage | Warning | Rethrow to preserve stack details |
 | [CA2252](quality-rules/ca2252.md) | Usage | Error | Opt in to preview features |
 | [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> |
-| CA2255 | Usage | Warning | The `ModuleInitializer` attribute should not be used in libraries |
+| [CA2255](quality-rules/ca2255.md) | Usage | Warning | The `ModuleInitializer` attribute should not be used in libraries |
 | CA2256 | Usage | Warning | All members declared in parent interfaces must have an implementation in a `DynamicInterfaceCastableImplementation`-attributed interface |
 | CA2257 | Usage | Warning | Members defined on an interface with the `DynamicInterfaceCastableImplementationAttribute` should be `static` |
 | CA2258 | Usage | Warning | Providing a `DynamicInterfaceCastableImplementation` interface in Visual Basic is unsupported |

docs/fundamentals/code-analysis/quality-rules/ca2255.md

@@ -0,0 +1,40 @@
+---
+title: "CA2255: The 'ModuleInitializer' attribute should not be used in libraries"
+description: "Learn about code analysis rule CA2255: The 'ModuleInitializer' attribute should not be used in libraries"
+ms.date: 11/15/2021
+ms.topic: reference
+f1_keywords:
+- CA2255
+- ModuleInitializerAttributeShouldNotBeUsedInLibraries
+helpviewer_keywords:
+- ModuleInitializerAttributeShouldNotBeUsedInLibraries
+- CA2255
+author: jeffhandley
+---
+# CA2255: The `ModuleInitializer` attribute should not be used in libraries
+
+| | Value |
+|-|-|
+| **Rule ID** |CA2255|
+| **Category** |[Usage](usage-warnings.md)|
+| **Fix is breaking or non-breaking** |Non-breaking|
+
+## Cause
+
+Applying <xref:System.Runtime.CompilerServices.ModuleInitializerAttribute> to a method within a Class Library.
+
+## Rule description
+
+Module initializers are intended to be used by application code to ensure an application's components are initialized before the application code begins executing. If library code declares a method with the <xref:System.Runtime.CompilerServices.ModuleInitializerAttribute>, it can interfere with application initialization and also lead to limitations in that application's trimming abilities. Library code should therefore not utilize the <xref:System.Runtime.CompilerServices.ModuleInitializerAttribute> attribute.
+
+## How to fix violations
+
+Instead of using methods with the <xref:System.Runtime.CompilerServices.ModuleInitializerAttribute>, a library should expose methods that can be used to initialize any components within the library, and allow the application to invoke the method during application initialization.
+
+## When to suppress warnings
+
+It is safe to suppress warnings from this rule if a solution uses a Class Library for code factoring purposes, and the <xref:System.Runtime.CompilerServices.ModuleInitializerAttribute> method is not part of a shared or distributed library or package.
+
+## See also
+
+- [Usage warnings](usage-warnings.md)

docs/fundamentals/code-analysis/quality-rules/index.md

@@ -187,6 +187,7 @@ The following table lists code quality analysis rules.
 > | [CA2250: Use `ThrowIfCancellationRequested`](ca2250.md) | `ThrowIfCancellationRequested` automatically checks whether the token has been canceled, and throws an `OperationCanceledException` if it has. |
 > | [CA2251: Use `String.Equals` over `String.Compare`](ca2251.md) | It is both clearer and likely faster to use `String.Equals` instead of comparing the result of `String.Compare` to zero. |
 > | [CA2252: Opt in to preview features](ca2252.md) | Opt in to preview features before using preview APIs. |
+> | [CA2255: The `ModuleInitializer` attribute should not be used in libraries](ca2255.md) | Module initializers are intended to be used by application code to ensure an application's components are initialized before the application code begins executing. |
 > | [CA2300: Do not use insecure deserializer BinaryFormatter](ca2300.md) | Insecure deserializers are vulnerable when deserializing untrusted data. An attacker could modify the serialized data to include unexpected types to inject objects with malicious side effects. |
 > | [CA2301: Do not call BinaryFormatter.Deserialize without first setting BinaryFormatter.Binder](ca2301.md) | Insecure deserializers are vulnerable when deserializing untrusted data. An attacker could modify the serialized data to include unexpected types to inject objects with malicious side effects. |
 > | [CA2302: Ensure BinaryFormatter.Binder is set before calling BinaryFormatter.Deserialize](ca2302.md) | Insecure deserializers are vulnerable when deserializing untrusted data. An attacker could modify the serialized data to include unexpected types to inject objects with malicious side effects. |

docs/fundamentals/code-analysis/quality-rules/usage-warnings.md

@@ -55,3 +55,4 @@ Usage rules support proper usage of .NET.
 |[CA2250: Use `ThrowIfCancellationRequested`](ca2250.md) | `ThrowIfCancellationRequested` automatically checks whether the token has been canceled, and throws an `OperationCanceledException` if it has.|
 |[CA2251: Use `String.Equals` over `String.Compare`](ca2251.md)|It is both clearer and likely faster to use `String.Equals` instead of comparing the result of `String.Compare` to zero.|
 |[CA2252: Opt in to preview features](ca2252.md)|Opt in to preview features before using preview APIs.|
+|[CA2255: The `ModuleInitializer` attribute should not be used in libraries](ca2255.md) | Module initializers are intended to be used by application code to ensure an application's components are initialized before the application code begins executing. |

docs/fundamentals/toc.yml

@@ -1310,6 +1310,8 @@ items:
             href: code-analysis/quality-rules/ca2251.md
           - name: CA2252
             href: code-analysis/quality-rules/ca2252.md
+          - name: CA2255
+            href: code-analysis/quality-rules/ca2255.md
       - name: Code style rules
         items:
         - name: Overview