If we have a scheme like so, with default lengthKind="delimited"
And the infoset:
Then we end up getting into StringLengthDelimited trying to cast a DIComplex (one) to a DISimple. Of course one should be a simple type, but it's not in the schema and we aren't doing a check somewhere the ensure it is a simple type. I don't think this is a problem with StringDelimitedUnparser, but somewhere else (maybe in the InfosetSource or NextElementResolver?)
See test_unexpectedChildNone in daffodil-test/src/test/scala-debug/edu/illinois/ncsa/daffodil/unparser/TestInfosetDebug.scala