Does .Net support curried generics?

Question

Suppose we have a nested generic class:

public class A<T> {
    public class B<U> { }
}

Here, typeof(A<int>.B<>) is in essence a generic class with two parameters where only the first is bound.

If I have a single class with two parameters

public class AB<T, U> { }

Is there a way to refer to " AB with T=int and U staying open"? If not, is this a C# limitation, or a CLR limitation?

Answer 1

Apparently it can't be done in C#, you have to specify either both type parameters, or none.

And it doesn't seem to be supported by the CLR either, A<int>.B<> and A<string>.B<> refer to the same type:

Type t1 = typeof(A<int>).GetNestedType("B`1");
Type t2 = typeof(A<string>).GetNestedType("B`1");
// t1.Equals(t2) is true

The enclosing type of both types is A<> (open generic type)

EDIT: further testing shows that typeof(A<int>.B<string>) is actually a generic type of arity 2, not a nested generic type of arity 1... typeof(A<int>.B<string>).GetGenericArguments() returns an array with typeof(int) and typeof(string) . So typeof(A<int>.B<>) would actually be equivalent to (AB)<int, > , which isn't supported (a generic type can't be partially closed)

Answer 2

Is this what you have in mind?

   class AB<T, U>
   {
      protected T t;
      U u;
   }

   class C<U> : AB<int, U>
   {
      public void Foo()
      {
         t = 5;
      }
   }

Answer 3

you can use the Func<int,int> generic to pass multiple parameters as a single function returning an type. Curried many to pass many arguments as a single parameter.

 [Fact]
    public async Task TestCurried()
    {
        Func<int, Func<int, int>> curried = x => y => x + y;
        int sum = curried(1)(3);
        Assert.Equal(sum.ToString(), "4");
    }
see
https://blog.tchatzigiannakis.com/generics-as-super-functions/