Here is my method call:

   var span = m_tracer.StartActiveSpan("FileTrace", SpanKind.Internal, in parentContext, null, null, startTime);

The method signature is defined as such:

public TelemetrySpan StartActiveSpan(
    string name,
    SpanKind kind = SpanKind.Internal,
    in SpanContext parentContext = default,
    SpanAttributes? initialAttributes = null,
    IEnumerable<Link>? links = null,
    DateTimeOffset startTime = default)

As you can see, the third parameter is decorated with the in qualifier. I must comply. The editor doesn’t complain –

But when I compile, here’s the result:

I threw the #error version in there so you can see what version of the compiler I am using. v9.0. (I also get the same error for v7.3.) Since the in keyword was introduced with C# v7.2 I am at a loss to understand this compiler error. Thanks for any advice which you can provide.