Bug 6700 Code assist should not just beep
suggest to show a status message: Could not complete due to syntax errors. This is also better for accessability reasons.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
IFile original= null;
		if (input instanceof IFileEditorInput)
			original= ((IFileEditorInput) input).getFile();
			
		if (original != null)
			dialog.setOriginalFile(original);
			
		if (dialog.open() == Dialog.CANCEL) {
			if (progressMonitor != null)
				progressMonitor.setCanceled(true);
			return;
		}
			
		IPath filePath= dialog.getResult();
		if (filePath == null) {
			if (progressMonitor != null)
				progressMonitor.setCanceled(true);
			return;
		}
			
		filePath= filePath.removeTrailingSeparator();
		final String fileName= filePath.lastSegment();
		IPath folderPath= filePath.removeLastSegments(1);
		if (folderPath == null) {
			if (progressMonitor != null)
				progressMonitor.setCanceled(true);			
			return;
		}