[API Proposal]: Add CallerType attribute to tell the method the current type that is invoking the current member.

[nathan130200]

Background and motivation

As the title says, the introduction of the attribute CallerTypeAttribute which will provide the method with the the type that is invoking the current member, as well as CallerMemberNameName.

I had this problem while writing a micro logger to handle tasks with more logging details. And when I realized that I was either creating a gigantic work-around or creating scoped loggers that store the methodbase instance or method name + type name.

And as .NET does not support expansive macros syntax like C++, it is not possible to simply write a macro that calls all the necessary functions by passing MethodBase.GetCurrentMethod() in each of them. (it would be something like #define INVOKE_LOG(LogInst, Msg) LogInst.WriteLine(Msg, MethodBase.GetCurrentMethod()))

API Proposal

namespace System.Runtime.CompilerServices
{
    [AttributeUsage(AttributeTargets.Parameter, Inherited = false)]
    public sealed class CallerTypeAttribute : Attribute
    {
        public CallerTypeAttribute();
    }
}

API Usage

static class Utilities
{

    void WriteToStdout([CallerType] Type currentType = default, [CallerMemberName] string memberName = default)
    {
        Console.WriteLine("[{0}::{1}]: invoked!", currentType.Name, memberName);
    }

}

The value of currentType will be filled with typeof(MyType) (or typeof(Utilities) in API usage example).

Alternative Designs

No response

Risks

No response

[jkotas]

Thank you for filling this suggestion. This is request for a new C# language feature. New language features are tracked in https://github.com/dotnet/csharplang repo. The attribute to support the C# language feature is secondary. We add such attributes to dotnet/runtime only once the language feature design is finalized.

This is duplicate of dotnet/csharplang#4984 that proposes a more generalized version of this proposal. Feel free to comment with your specific scenario on that proposal.

cc @jaredpar

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