Fail to get generic type

[cipri7329]

I have the following class:

    public class MyGenericArray<T>
    {
        private T[] array;

        public MyGenericArray(int size)
        {
            array = new T[size + 1];
        }

        public T getItem(int index)
        {
            var in2 = index + 1;
            in2 = index - in2;
            index = index + 1 - in2 - 1;
            return array[index];
        }
    }

I use dnlib to make some changes at the cil code level.
Inside the getItem() method, I want to get the class type of the this parameter, ldarg.0
I am looking in the param.Type where
var param = ((Parameter)_instruction.Operand);

I have searched through all the available fields but I could not find it.
In fact, what I get is

ConsoleCalculator.BasicTests/MyGenericArray`1 

and I expect to find

ConsoleCalculator.BasicTests/MyGenericArray`1<!T> 

I don't understand why the <!T> is missing.
For the field private T[] array; the class is displayed correctly, with the <!T> at the end.