Compiler Warning (level 1) CS3012

You cannot specify the CLSCompliant attribute on a module that differs from the CLSCompliant attribute on the assembly

In order for a module to be compliant with the Common Language Specification (CLS) through [module:System.CLCSompliant(true)], it must be built with the /target:module compiler option. For more information on the CLS, see Common Language Specification.

Example

The following example, when built without /target:module, generates CS3012:

// CS3012.cs
// compile with: /W:1

[module:System.CLSCompliant(true)]   // CS3012
public class C
{
    public static void Main()
    {
    }
}