Bug 127655 [api] Must have a way to query quick assist context from source viewer
I20060214-0010 [api] Must have a way to query quick assist context from text viewer. In addition, quick assistant install must specify that besides ITextViewer also ITextViewerExtension7 must be present in order to get the invocation context. ==> assertion failure if this is not met.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/correction/JavaCorrectionProcessor.java
if (annotation instanceof SimpleMarkerAnnotation) {
			return hasCorrections(((SimpleMarkerAnnotation) annotation).getMarker());
		}
		return false;
	}
	private static boolean hasCorrections(IMarker marker) {
		if (marker == null || !marker.exists())
			return false;
		IMarkerHelpRegistry registry= IDE.getMarkerHelpRegistry();
		return registry != null && registry.hasResolutions(marker);
	}
	public static boolean hasAssists(IInvocationContext context) {
		ContributedProcessorDescriptor[] processors= getAssistProcessors();
		SafeHasAssist collector= new SafeHasAssist(context);
		for (int i= 0; i < processors.length; i++) {
			collector.process(processors[i]);
			if (collector.hasAssists()) {
				return true;
			}
		}
		return false;
	}
	private JavaCorrectionAssistant fAssistant;
	private String fErrorMessage;
	/*
	 * Constructor for JavaCorrectionProcessor.
	 */
	public JavaCorrectionProcessor(JavaCorrectionAssistant assistant) {
		fAssistant= assistant;
		fAssistant.addCompletionListener(new ICompletionListener() {