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, 10 insertions, 3 deletions

diff --git a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
index fc532f5d44..ef5872986c 100644
--- a/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
+++ b/src/compiler/scala/tools/nsc/ast/parser/Parsers.scala
@@ -166,13 +166,20 @@ self =>
     def syntaxError(offset: Int, msg: String): Unit = throw new MalformedInput(offset, msg)
     def incompleteInputError(msg: String): Unit = throw new MalformedInput(source.content.length - 1, msg)
 
-    /** the markup parser */
-    lazy val xmlp = new MarkupParser(this, preserveWS = true)
-
     object symbXMLBuilder extends SymbolicXMLBuilder(this, preserveWS = true) { // DEBUG choices
       val global: self.global.type = self.global
     }
 
+    /** the markup parser
+     * The first time this lazy val is accessed, we assume we were trying to parse an xml literal.
+     * The current position is recorded for later error reporting if it turns out
+     * that we don't have the xml library on the compilation classpath.
+     */
+    private[this] lazy val xmlp = {
+      currentUnit.encounteredXml(o2p(in.offset))
+      new MarkupParser(this, preserveWS = true)
+    }
+
     def xmlLiteral() : Tree = xmlp.xLiteral
     def xmlLiteralPattern() : Tree = xmlp.xLiteralPattern
   }