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/CompletionProposalComputerDescriptor.java
public String getName() {
		return fName;
	}
	
	/**
	 * Returns the partition types of the described extension.
	 * 
	 * @return the set of partition types (element type: {@link String})
	 */
	public Set getPartitions() {
		return fPartitions;
	}
	
	/**
	 * Returns a cached instance of the computer as described in the
	 * extension's xml. The computer is
	 * {@link #createComputer() created} the first time that this method
	 * is called and then cached.
	 * 
	 * @return a new instance of the completion proposal computer as
	 *         described by this descriptor
	 * @throws CoreException if the creation fails
	 * @throws InvalidRegistryObjectException if the extension is not
	 *         valid any longer (e.g. due to plug-in unloading)
	 */
	private synchronized ICompletionProposalComputer getComputer() throws CoreException, InvalidRegistryObjectException {
		if (fComputer == null && (fActivate || isPluginLoaded()))
			fComputer= createComputer();
		return fComputer;
	}