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/CompletionProposalCategory.java
* 
	 * @return <code>true</code> if the category contains any computers, <code>false</code>
	 *         otherwise
	 */
	public boolean hasComputers() {
		List descriptors= fRegistry.getProposalComputerDescriptors();
		for (Iterator it= descriptors.iterator(); it.hasNext();) {
			CompletionProposalComputerDescriptor desc= (CompletionProposalComputerDescriptor) it.next();
			if (desc.getCategory() == this)
				return true;
		}
		return false;
	}
	
	/**
	 * Returns <code>true</code> if the category contains any computers in the given partition, <code>false</code>
	 * otherwise.
	 * 
	 * @param partition the partition
	 * @return <code>true</code> if the category contains any computers, <code>false</code>
	 *         otherwise
	 */
	public boolean hasComputers(String partition) {
		List descriptors= fRegistry.getProposalComputerDescriptors(partition);
		for (Iterator it= descriptors.iterator(); it.hasNext();) {
			CompletionProposalComputerDescriptor desc= (CompletionProposalComputerDescriptor) it.next();
			if (desc.getCategory() == this)
				return true;
		}
		return false;