C# Error CS8127 – Tuple element names must be unique.

C# Error

CS8127 – Tuple element names must be unique.

Reason for the Error & Solution

Tuple element names must be unique.

Example

The following sample generates CS8127:

// CS8127.cs (7,0)

internal struct NewStruct
{
    public int a;
    public int b;

    public static implicit operator (int a, int a)(NewStruct value)
    {
        return (value.a, value.b);
    }
}

To correct this error

Ensuring the names of elements within a tuple declaration are unique corrects this error:

    public static implicit operator (int a, int b)(NewStruct value)
    {
        return (value.a, value.b);
    }