Using a dev build, I opened (File > Open) maven.indexer/src/org/netbeans/modules/maven/indexer/NexusRepositoryIndexerImpl.java from a clean checkout of release70_beta. This had a bunch of error marks, as expected - all the Maven libraries were not yet unpacked. I then did ant -f maven.indexer/build.xml to make sure all binary dependencies were in place; when that finished, the IDE rescanned the file. Now it had just two error marks, both anomalous:

1. Type hierarchy problem.

  iur.setResourceFetcher(new WagonFetcher(listener));

constructor WagonFetcher in class org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl.WagonFetcher cannot be applied to given types;
  required: org.apache.maven.wagon.events.TransferListener
  found: org.netbeans.modules.maven.indexer.RemoteIndexTransferListener
  reason: actual argument org.netbeans.modules.maven.indexer.RemoteIndexTransferListener cannot be converted to org.apache.maven.wagon.events.TransferListener by method invocation conversion

If you navigate to the constructor in the same file

  WagonFetcher(TransferListener listener)

you can jump to TransferListener in cache source; and you can jump to RemoteIndexTransferListener in project sources, which implements TransferListener.

2. Throws-clause problem.

                ProjectBuildingResult res = getEmbedder().buildProject(projectArtifact, dpbr);
                if (res.getProject() != null) {
                    return res.getProject();
                }
            } catch (ProjectBuildingException ex) {

"ProjectBuildingException not thrown in body of corresponding try statement." or a similar message. "getEmbedder().buildProject" also produces no code completion. After jumping to MavenEmbedder, the file is marked with an error badge, though there is no line in error; then some scanning happens, and the badge disappears from MavenEmbedder; then I jump back to NexusRepositoryIndexerImpl and all error marks disappear from it, after

WARNING [org.netbeans.modules.java.source.tasklist.IncorrectErrorBadges]: Incorrect error badges detected, file=maven.indexer/src/org/netbeans/modules/maven/indexer/NexusRepositoryIndexerImpl.java.
WARNING [org.netbeans.modules.java.source.tasklist.IncorrectErrorBadges]: Going to recompute root=maven.indexer/src, files in error=[file:maven.indexer/src/org/netbeans/modules/maven/indexer/NexusRepositoryIndexerImpl.java].
WARNING [org.openide.util.WeakListenerImpl]: Can't remove java.beans.PropertyChangeListener using method removePropertyChangeListener from org.netbeans.modules.editor.NbEditorDocument@16bd9ec, mimeType='text/x-java', kitClass=null, length=6247, version=1, file=org.netbeans.modules.java.JavaDataObject@8d8199[MasterFileObject[maven.indexer/src/org/netbeans/modules/maven/indexer/RemoteIndexTransferListener.java@d5a5cd:1f0c26a,valid=true]]