C# Function Overloading in the New .NET 6 Console Template is Not Working

May 13, 2022

I am getting errors trying to overload the function Print(object) in the new .NET 6 C# console app template (top-level statements).

void Print(object obj) => Print(obj, ConsoleColor.White);

void Print(object obj, ConsoleColor color)
{
    Console.ForegroundColor = color;
    Console.WriteLine(obj);
    Console.ResetColor();
}

Errors are:

From Print(obj, ConsoleColor.White) -> No overload for method Print() that takes 2 arguments
From Print(object obj, ConsoleColor color) -> A local variable or function named 'Print' is already defined in this scope

I tried to switch their order but it still throws errors. What’s going on?

>Solution :

Contents of top-level is assumed to be an internals of Main, so you declared two local functions inside Main. And local functions does not support overloading.

You can:

switch to the old style template with full specification of class

class Program
{
 static void Main(){}

 void Print(object obj) => Print(obj, ConsoleColor.White);

 void Print(object obj, ConsoleColor color)
 {
    Console.ForegroundColor = color;
    Console.WriteLine(obj);
    Console.ResetColor(); 
 }
}

to stay with new template, but wrap your function into the separate class

var c = new C();
c.Print("test");

public class C{
  public void Print(object obj) => Print(obj, ConsoleColor.White);

     void Print(object obj, ConsoleColor color)
     {
        Console.ForegroundColor = color;
        Console.WriteLine(obj);
        Console.ResetColor(); 
     }

}

Related github isse with some technical details: https://github.com/dotnet/docs/issues/28231