Compiler Error CS0815

Cannot assign 'expression' to an implicitly typed local

An expression that is used as the initializer for an implicitly typed variable must have a type. Because anonymous function expressions, method group expressions, and the null literal expression do not have a type, they are not appropriate initializers. An implicitly typed variable cannot be initialized with a null value in its declaration, although it can later be assigned a value of null.

To correct this error

• Provide an explicit type for the variable.

Example

The following code generates CS0815:

// cs0815.cs
class Test
{
    public static int Main()
    {
        var d = s => -1; // CS0815
        var e = (string s) => 0; // CS0815
        var p = null;//CS0815
        var del = delegate(string a) { return -1; };// CS0815
        return -1;
    }
}

See Also

Reference

Implicitly Typed Local Variables (C# Programming Guide)