Question

I have a method in VB.NET which is just a helper for throwing
exceptions. It will always throw an exception and never returns
However the compiler does not detect this function as a terminating
code path and thus I get warning if I use
variables later on in the code that are not initialized via the exception code path.

Function Foo(y as Integer) As Boolean
    dim x as boolean
    if y > 10
        x = 20
    else
        ThrowHelperFunction("Ouch")
    end if
    return x
End Function

The warning is that x is not initialized on all code paths.

Answer 1

Update:

There is a way since .NET Standard 2.1 (.NET 5 and newer):

[DoesNotReturn]
private void FailFast()
{
    throw new InvalidOperationException();
}

Or conditionally:

private void FailFastIf([DoesNotReturnIf(true)] bool isNull)
{
    if (isNull)
    {
        throw new InvalidOperationException();
    }
}

https://learn.microsoft.com/en-us/dotnet/api/system.diagnostics.codeanalysis.doesnotreturnattribute?view=net-8.0

Original answer:

I don’t think that you can change that behavior. Instead you can do something like:

Function Foo(y as Integer) As Boolean
    dim x as boolean
    if y > 10
        x = 20
    else
        throw CreateExceptionHelperFunction("Ouch")
    end if
    return x
End Function

That is, the helper function can still do some processing. But it will return an exception instead of throwing it.