docs: @Check
  	public void checkTopElementsAreUnique(SarlScript script) {
  		final Multimap<String, XtendTypeDeclaration> name2type = HashMultimap.create();
  		for (final XtendTypeDeclaration declaration : script.getXtendTypes()) {
  			final String name = declaration.getName();
  			if (!Strings.isEmpty(name)) {
  				name2type.put(name, declaration);
  			}
  		}
  		for (final String name: name2type.keySet()) {
  			final Collection<XtendTypeDeclaration> types = name2type.get(name);
  			if (types.size() > 1) {
  				for (final XtendTypeDeclaration type: types) {
  					error(
  							MessageFormat.format(Messages.SARLValidator_93, name),
  							type,
  							XtendPackage.Literals.XTEND_TYPE_DECLARATION__NAME,
  							DUPLICATE_TYPE_NAME);
  				}
  			}
  		}
  	}