Function returns a #VALUE! when it should return #NAME?

Hello guys!
In Excel:
`=HelloWorld(TRUF)`
Returns `"Hello World!"` even if parameter `TRUF` returns `#NAME?` in Function Argument Window (`Ctrl + A`).
`=HelloWorld(TRUF)` should return `#NAME?`.

C# Code:
```C#
using ExcelDna.Integration;

public static class MyFunctions
{
[ExcelFunction(Description = "Hello world")]
public static string HelloWorld(
[ExcelArgument("True or False?")] bool foo)
{
return "Hello World!";
}
}
```

Thanks