top-level statements must precede namespace and type declarations. [assembly-csharp]

//Yes. Top-level statements must precede namespaces and classes.
//However, they're only supported in C# 9.0 with .NET 5.0 and VS 2019 v16.8

using System;
Console.WriteLine("Hello World");

//Example above uses top-level statement instead of manually constructing
// a namespace or Main method entry point.

using System;

//THESE ARE TOP-LEVEL STATEMENT AGAIN. Placed above namespaces and classes
Person p1 = new Person(Name = "Alice", Age = 37);
Console.WriteLine($"{0} is {1}", p1.Name, p1.Age);

namespace examples
{
  public class Person
  {
  	public string Name { get; set; }
    public int Age { get; set; }
  }
}