docs: public @Nonnull
      ClassDescriptor getClassDescriptor(@SlashedClassName String className) {
          assert className.indexOf('.') == -1;
          ClassDescriptor classDescriptor = classDescriptorMap.get(className);
          if (classDescriptor == null) {
              if (MODULE_INFO.getClassName().equals(className)) {
                  // don't allow module info to be added to the map,
                  // which could be used to check referenced classes
                  return MODULE_INFO;
              }
              classDescriptor = new ClassDescriptor(className);
              classDescriptorMap.put(className, classDescriptor);
          }
          return classDescriptor;
      }