Is a testamentary trust beneficiary predeceasing testator treated like a surviving beneficiary disclaiming interest?

Example 5(a) given in the Uniform Probate Code under SECTION 2-1106 DISCLAIMER OF INTEREST IN PROPERTY reads as follows: "Father’s will creates a testamentary trust to pay income to his son S for his life, and on his death to pay the remainder to S’s descendants then living, by representation. If S disclaims his life income interest in the trust, he will be deemed to have died immediately before Father’s death. The disclaimed interest, S’s income interest, came into possession and enjoyment at Father’s death as would any present interest created by will and, therefore, the time of distribution is Father’s death. If the income beneficiary of a testamentary trust does not survive the testator, the income interest is not created and the next interest in the trust takes effect. Since the next interest in Father’s trust is the remainder in S’s descendants, the trust property will pass to S’s descendants who survive Father by representation. It is immaterial under the statute that the actual situation at S’s death might be different with different descendants entitled to the remainder." My question concerns the stated rule that remainder beneficiaries of a testamentary trust inherit when the income beneficiary does not survive the testator. Absent any other considerations (e.g., anti-lapse), does this rule apply to testamentary trusts in general or is it specific to this context of disclaimed interest?