[API Proposal]: Add ExcludeStatics to RequiresUnreferencedCode and RequiresDynamicCode #117524
Description
Background and motivation
Adding RequiresUnreferencedCode and RequiresDynamicCode to a type has a unique value that adding it to methods does not: it allows you to address trim warnings inside method overrides or interface implementations without modifying the base method/interface.
Sometimes this is necessary because you cannot modify the base method/interface (e.g., it lives in another library).
Unfortunately, RequiresUnreferencedCode has a second effect that can not be disabled currently: it marks all static members inside the type as RUC. This creates a challenge. If you have an instance method override/implementation that needs RUC, you have to apply it to the type. But if you need to use one of the static methods in a trimmed scenario, that creates a warning. The result is a mandatory suppression somewhere.
As it is a goal to never require users to have to add suppressions to supported scenarios, we need a new piece of functionality: allow users to disable the effect of RUC/RDC on nested static members.
API Proposal
namespace System.Runtime.CompilerServices;
// Existing type
internal sealed class RequiresUnreferencedCodeAttribute : Attribute
{
+ public bool ExcludeStatics { get; init; }
}
// Existing type
internal sealed class RequiresDynamicCodeAttribute : Attribute
{
+ public bool ExcludeStatics { get; init; }
}API Usage
// Assembly Program, being trimmed
public class Program
{
public static void Main()
{
C.HelperMethod(); // No warning
C.RucHelper(); // Warning
using var c = new C(); // Warning on ctor
}
}
// Assembly C, partially trimmable
[RequiresUnreferencedCode("msg", ExcludeStatics = true)]
public class C : IDisposable
{
public void Dispose()
{
// ... implementation uses RUC
}
public static void HelperMethod()
{
// ...
}
[RequiresUnreferencedCode("msg2")]
public static void RucHelper()
{
// ...
}
}Alternative Designs
No response
Risks
No response