Set scene for Predef.$scope's demise.

When there's no Predef.$scope but xml is being used,
the compiler aliases scala.xml.TopScope to $scope.

There must be a scala.xml package when xml literals were parsed.

For compatibility with the old library, which relied on $scope being in scope,
synthesize a `import scala.xml.{TopScope => $scope}` when xml is needed,
but there's no Predef.$scope and the old library is detected (scala.xml.TopScope exists).

1 files changed, 14 insertions, 0 deletions

diff --git a/src/compiler/scala/tools/nsc/CompilationUnits.scala b/src/compiler/scala/tools/nsc/CompilationUnits.scala
index 15d365ab8c..b52e6fdf57 100644
--- a/src/compiler/scala/tools/nsc/CompilationUnits.scala
+++ b/src/compiler/scala/tools/nsc/CompilationUnits.scala
@@ -34,6 +34,20 @@ trait CompilationUnits { self: Global =>
     /** the content of the compilation unit in tree form */
     var body: Tree = EmptyTree
 
+    /** The position of the first xml literal encountered while parsing this compilation unit.
+     * NoPosition if there were none. Write-once.
+     */
+    private[this] var _firstXmlPos: Position = NoPosition
+
+    /** Record that we encountered XML. Should only be called once. */
+    protected[nsc] def encounteredXml(pos: Position) = _firstXmlPos = pos
+
+    /** Does this unit contain XML? */
+    def hasXml = _firstXmlPos ne NoPosition
+
+    /** Position of first XML literal in this unit. */
+    def firstXmlPos = _firstXmlPos
+
     def exists = source != NoSourceFile && source != null
 
     /** Note: depends now contains toplevel classes.