XQuery-Update: Target node of insert expression is not updateable

Question

Running this code

copy $foo := <foo />
modify (
  insert node <bar /> into $foo
)
return $foo

in Saxon-EE 9.6.0.7 (form Oxygen 18) I get the Error

Target node of insert expression is not updateable

BaseX returns <foo><bar/></foo>

Who is right? Is there another way to modify any xml-expression, not just those loaded by doc() (which works with Saxon)?

Answer 1

You need to set the option -tree:linked to ensure that Saxon runs using an updatable tree model. The default tree model is immutable.