Why Compiler Error CS0416 exist?

[soroshsabz]

ITNOA

as you see in https://learn.microsoft.com/en-us/dotnet/csharp/misc/cs0416

'type parameter': an attribute argument cannot use type parameters

A type parameter was used as an attribute argument, which is not allowed. Use a non-generic type.

The following sample generates CS0416:

// CS0416.cs  
public class MyAttribute : System.Attribute  
{  
   public MyAttribute(System.Type t)  
   {  
   }  
}  
  
class G<T>  
{  
  
   [MyAttribute(typeof(G<T>))]  // CS0416  
   public void F()  
   {  
   }  
  
}

My question is, why we cannot pass typeof generic type to attribute?

thanks

[TahirAhmadov]

This is probably because the type information has to be encoded somehow to be stored in the assembly, and there are technical reasons why encoding a generic argument type is difficult or impossible. There was a discussion about this a few months ago (no way I can find it now); there is a feasible way to make this work, but it requires some heavy lifting WRT both runtime and language changes, and I don't think it's high priority enough to work on right now.

[hez2010]

Attributes are stored as constants in assembly, so it is impossible to use a type parameter that cannot be resolved at compile time.