Compiler Warning (level 2) CS0458

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The result of the expression is always 'null' of type 'type name'

This warning is caused by a nullable expression that always results in null.

The following code generates warning CS0458.

Example

This example illustrates a number of the different operations with nullable types that will cause this error.

// CS0458.cs
using System;
public  class Test 
{
    public static void Main()
    {
        int a = 5;
        int? b = a + null;    // CS0458
        int? qa = 15;
        b = qa + null;        // CS0458
        b -= null;            // CS0458
        int? qa2 = null;
        b = qa2 + null;       // CS0458
        qa2 -= null;          // CS0458
    }
}