public class OverlayIndex implements IndexView {
    private final List<IndexView> indices;

    Collection<ClassInfo> getKnownClasses() {
        // call `getKnownClasses` on each index, in order, keep track of already seen class names
        // and skip a class if its name was already seen
    }

    ClassInfo getClassByName(DotName className) {
        // iterate through `indices` and return the first found
    }

    Collection<ClassInfo> getKnownDirectSubclasses(DotName className) {
        // don't know here? perhaps call `getKnownDirectSubclasses` on each index, in order,
        // keep track of already seen class names and skip a class if its name was already seen
    }

    Collection<ClassInfo> getAllKnownSubclasses(DotName className) {
        // don't know here? perhaps call `getAllKnownSubclasses` on each index, in order,
        // keep track of already seen class names and skip a class if its name was already seen
    }

    Collection<ClassInfo> getKnownDirectImplementors(DotName className) {
        // don't know here? perhaps call `getKnownDirectImplementors` on each index, in order,
        // keep track of already seen class names and skip a class if its name was already seen
    }

    Collection<ClassInfo> getAllKnownImplementors(final DotName interfaceName) {
        // don't know here? perhaps call `getAllKnownImplementors` on each index, in order,
        // keep track of already seen class names and skip a class if its name was already seen
    }

    Collection<AnnotationInstance> getAnnotations(DotName annotationName) {
        // call `getAnnotations` on each index, keep track of already seen `AnnotationTarget`s
        // and skip an `AnnotationTarget` if it was already seen
        //
        // note that `AnnotationTarget` doesn't have well defined equality, so this may be harder than it seems
    }

    Collection<AnnotationInstance> getAnnotationsWithRepeatable(DotName annotationName, IndexView index) {
        // same as getAnnotations
    }

    Collection<ModuleInfo> getKnownModules() {
        // same as `getKnownClasses` probably?
    }

    ModuleInfo getModuleByName(DotName moduleName) {
        // same as `getClassByName` probably?
    }

    Collection<ClassInfo> getKnownUsers(DotName className) {
        // call `getKnownUsers` on each index, in order, keep track of already seen class names
        // and skip a class if its name was already seen
    }
}