Compiler Error CS1952

An expression tree lambda may not contain a method with variable arguments

The unsupported __arglist keyword is not allowed in lambda expressions that compile to expression trees.

To correct this error

• Forget that you ever heard of __arglist.

Example

The following code produces CS1952:

// cs1952.cs
using System;
using System.Linq.Expressions;

class Test
{
    public static int M(__arglist)
    {
        return 1;
    }

    static int Main()
    {
        Expression<Func<int, int>> f = x => Test.M(__arglist(x)); // CS1952
        return 1;
    }
}