CA2255: The `ModuleInitializer` attribute should not be used in libraries

#Cause

Applying 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 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 System.Runtime.CompilerServices.ModuleInitializerAttribute attribute.

#How to fix violations

Instead of using methods marked with System.Runtime.CompilerServices.ModuleInitializerAttribute, the 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 System.Runtime.CompilerServices.ModuleInitializerAttribute method is not part of a shared or distributed library or package.

#Suppress a warning

If you just want to suppress a single violation, add preprocessor directives to your source file to disable and then re-enable the rule.

#pragma warning disable CA2255
// The code that's violating the rule is on this line.
#pragma warning restore CA2255

To disable the rule for a file, folder, or project, set its severity to none in the configuration file.

[*.{cs,vb}]
dotnet_diagnostic.CA2255.severity = none

To disable this entire category of rules, set the severity for the category to none in the configuration file.

[*.{cs,vb}]
dotnet_analyzer_diagnostic.category-Usage.severity = none

For more information, see How to suppress code analysis warnings.

#See also

• Usage warnings