Bug 117493 [content assist] CompletionRequestor#completionFailure(IProblem)) is ignored
This got introduced after 3.2 M1 (i.e. broken in 3.2 M2 and newer). If completion fails we now always show: "No completion available." instead of the real error text. Example: for (Iterator i=things.iterator(); i.<ctrl-space> // Iterator not yet imported)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/ContentAssistProcessor.java
monitor.done();
		return result;
	}
	private List collectProposals(ITextViewer viewer, int offset, IProgressMonitor monitor, TextContentAssistInvocationContext context) {
		List proposals= new ArrayList();
		List providers= getCategories();
		for (Iterator it= providers.iterator(); it.hasNext();) {
			CompletionProposalCategory cat= (CompletionProposalCategory) it.next();
			List computed= cat.computeCompletionProposals(context, fPartition, new SubProgressMonitor(monitor, 1));
			proposals.addAll(computed);
		}
		
		return proposals;
	}
	/**
	 * Filters and sorts the proposals. The passed list may be modified
	 * and returned, or a new list may be created and returned.
	 * 
	 * @param proposals the list of collected proposals (element type:
	 *        {@link ICompletionProposal})
	 * @param monitor a progress monitor
	 * @param context TODO
	 * @return the list of filtered and sorted proposals, ready for
	 *         display (element type: {@link ICompletionProposal})
	 */
	protected List filterAndSortProposals(List proposals, IProgressMonitor monitor, TextContentAssistInvocationContext context) {
		return proposals;
	}
	/*
	 * @see org.eclipse.jface.text.contentassist.IContentAssistProcessor#computeContextInformation(org.eclipse.jface.text.ITextViewer, int)