vested indefeasibly

After referring to the meaning of “vested indefeasibly” discussed in IT-449R, CCRA stated:

Therefore, where the rights of the beneficiaries in the trust are not vested and can be changed for any reason by the trustee or otherwise, the interests in the trust cannot be regarded as vested indefeasibly.

(a) What is required for all interests in a trust to have vested indefeasibly; and
(b) how is this disclosed on the trust return?

(a) CRA noted that its comments in 2018-0744111C6, as to what is required in order for an interest in a trust to vest indefeasibly, still apply.

For purposes of the 21-year deemed disposition rule, a trust does not include a trust "all interests in which … have vested indefeasibly". What is required for this to occur?

Respecting a question as to whether that all interests in a Trust had vested indefeasibly for purposes of the predecessor of para. (g), CRA referred to The Queen v. Boger Estate, 93 DTC 5276 (FCA), and stated:

In order to apply this interpretation it is necessary to ascertain whether the beneficiaries' respective interests in the Trust had vested without either a condition subsequent or determinable limitation attached thereto.

The trust indenture of a discretionary trust will be modified for it to become a non-discretionary trust, in order to avoid the application of the 21-year realization rule under s. 104(4)(b). Before indicating that it could not comment on whether such amendments would accomplish this end, and on their consequences, without examining the amendments and other facts in the context of a ruling application, and aftger noting that it