Fixup of the XMl discardable.

Author: michaelnebel

csharp/ql/lib/semmle/code/csharp/internal/Overlay.qll

@@ -30,17 +30,6 @@ private class DiscardableEntityBase extends @locatable {
   string toString() { none() }
 }
 
-/**
- * A class of Xml locatables that can be discarded from the base.
- */
-overlay[local]
-private class DiscardableXmlEntity extends DiscardableEntityBase instanceof @xmllocatable {
-  /** Gets the path to the file in which this element occurs. */
-  override string getFilePath() {
-    exists(@location_default loc | result = getLocationFilePath(loc) | xmllocations(this, loc))
-  }
-}
-
 /**
  * A class of elements that can be discarded from the base.
  */
@@ -121,6 +110,17 @@ private predicate discardLocation(@location_default loc) {
   exists(string path | discardableLocation(loc, path) | overlayChangedFiles(path))
 }
 
+/**
+ * A class of Xml locatables that can be discarded from the base.
+ */
+overlay[local]
+private class DiscardableXmlEntity extends DiscardableEntityBase instanceof @xmllocatable {
+  /** Gets the path to the file in which this element occurs. */
+  override string getFilePath() {
+    exists(@location_default loc | result = getLocationFilePath(loc) | xmllocations(this, loc))
+  }
+}
+
 overlay[local]
 private predicate overlayXmlExtracted(string file) {
   exists(DiscardableXmlEntity dxe |