Fixed equality and string representation of xml attributes with null value

Prior to this patch <t a={ null: String }/> was not equal to <t/> and
it's string representation was "<t ></t>" instead of "<t></t>"

This includes changing MetaData.normalize() so that it doesn't reverse
the chain. On the downside, the iterate function in MetaData.normalize()
is not tail-recursive now.

1 files changed, 14 insertions, 0 deletions

diff --git a/test/files/run/xml-attribute.scala b/test/files/run/xml-attribute.scala
new file mode 100644
index 0000000000..2b83f70b22
--- /dev/null
+++ b/test/files/run/xml-attribute.scala
@@ -0,0 +1,14 @@
+import xml.Node
+
+object Test {
+  def main(args: Array[String]): Unit = {
+    val noAttr = <t/>
+    val attrNull = <t a={ null: String }/>
+    val attrNone = <t a={ None: Option[Seq[Node]] }/>
+    assert(noAttr == attrNull)
+    assert(noAttr == attrNone)
+    assert(noAttr.toString() == "<t></t>")
+    assert(attrNull.toString() == "<t></t>")
+    assert(attrNone.toString() == "<t></t>")
+  }
+}