code: static ReferenceTypeSignature parseClassBound(final Parser parser, final String definingClassName)
              throws ParseException {
          parser.expect(':');
          // May return null if there is no signature after ':' (class bound signature may be empty)
          return parseReferenceTypeSignature(parser, definingClassName);
      }
docs: Parse a class bound.
  
  @param parser
  The parser.
  @param definingClassName
  The class containing the type descriptor.
  @return The parsed class bound.
  @throws ParseException
  If the type signature could not be parsed.