xml namesapce (scope) not handled correctly when mixing xml literal and scala code

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in scala console

following code works correctly:

scala> val e = <ns:elems xmlns:ns="http://">{List(1, 2, 3).map(x => <ns:elem>{x}</ns:elem>) ++ List(4, 5, 6).map(x => <ns:elem>{x}</ns:elem>)}</ns:elems>
e: scala.xml.Elem = <ns:elems xmlns:ns="http://"><ns:elem>1</ns:elem><ns:elem>2</ns:elem><ns:elem>3</ns:elem><ns:elem>4</ns:elem><ns:elem>5</ns:elem><ns:elem>6</ns:elem></ns:elems>

scala> e \\ "elem"
res0: scala.xml.NodeSeq = NodeSeq(<ns:elem xmlns:ns="http://">1</ns:elem>, <ns:elem xmlns:ns="http://">2</ns:elem>, <ns:elem xmlns:ns="http://">3</ns:elem>, <ns:elem xmlns:ns="http://">4</ns:elem>, <ns:elem xmlns:ns="http://">5</ns:elem>, <ns:elem xmlns:ns="http://">6</ns:elem>)

namespace is correct in each child node.

while if using method call, namespace gets lost:

scala> def f(l: List[Int]) = l.map(x => <ns:elem>{x}</ns:elem>)
f: (l: List[Int])List[scala.xml.Elem]

scala> val e = <ns:elems xmlns:ns="http://">{f(List(1, 2, 3)) ++ f(List(4, 5, 6))}</ns:elems>
e: scala.xml.Elem = <ns:elems xmlns:ns="http://"><ns:elem>1</ns:elem><ns:elem>2</ns:elem><ns:elem>3</ns:elem><ns:elem>4</ns:elem><ns:elem>5</ns:elem><ns:elem>6</ns:elem></ns:elems>

scala> e \\ "elem"
res2: scala.xml.NodeSeq = NodeSeq(<ns:elem>1</ns:elem>, <ns:elem>2</ns:elem>, <ns:elem>3</ns:elem>, <ns:elem>4</ns:elem>, <ns:elem>5</ns:elem>, <ns:elem>6</ns:elem>)

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Imported From: https://issues.scala-lang.org/browse/SI-4865?orig=1
Reporter: Hongxin Liang (honnix)
Affected Versions: 2.9.0

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@SethTisue said:
The scala-xml library is now community-maintained. Issues with it are now tracked at https://github.com/scala/scala-xml/issues instead of here in the Scala JIRA.

Interested community members: if you consider this issue significant, feel free to open a new issue for it on GitHub, with links in both directions.