return nullableTypeOf(type.getUpperBound());
    }

    /**
     * Returns the first declared lower-bound of the wildcard type expression represented by this type.
     *
     * @return null if no lower-bound has been explicitly declared.
     * @since 6.0
     */
    @Nullable
    public TypeOf<?> getLowerBound() {
        return nullableTypeOf(type.getLowerBound());
    }