ClassSymbol accessConstructorTag() {
        ClassSymbol topClass = currentClass.outermostClass();
        Name flatname = names.fromString("" + topClass.getQualifiedName() +
                                         target.syntheticNameChar() +
                                         "1");
        ClassSymbol ctag = chk.compiled.get(flatname);
        if (ctag == null)
            ctag = makeEmptyClass(STATIC | SYNTHETIC, topClass);
        // keep a record of all tags, to verify that all are generated as required
        accessConstrTags = accessConstrTags.prepend(ctag);
        return ctag;
    }