diff --git a/parsing.api/src/org/netbeans/modules/parsing/impl/TaskProcessor.java b/parsing.api/src/org/netbeans/modules/parsing/impl/TaskProcessor.java
--- a/parsing.api/src/org/netbeans/modules/parsing/impl/TaskProcessor.java
+++ b/parsing.api/src/org/netbeans/modules/parsing/impl/TaskProcessor.java
@@ -889,10 +889,10 @@
         boolean setCurrentTask (Request reference) throws InterruptedException {
             boolean result = false;
             assert !parserLock.isHeldByCurrentThread();
-            assert reference == null || reference.cache == null || !Thread.holdsLock(reference.cache.getSnapshot().getSource());
+            assert reference == null || reference.cache == null || !Thread.holdsLock(INTERNAL_LOCK);
             synchronized (CRR_LOCK) {
                 while (this.canceledReference!=null) {
-                    assert canceledReference.cache == null || !Thread.holdsLock(canceledReference.cache.getSnapshot().getSource());
+                    assert canceledReference.cache == null || !Thread.holdsLock(INTERNAL_LOCK);
                     CRR_LOCK.wait();
                 }
                 result = this.canceled;