Cal. Probate Code § 15304

(a) If the settlor is a beneficiary of a trust created by the settlor and the settlor’s interest is subject to a provision restraining the voluntary or involuntary transfer of the settlor’s interest, the restraint is invalid against transferees or creditors of the settlor. The invalidity of the restraint on transfer does not affect the validity of the trust. (b) If the settlor is the beneficiary of a trust created by the settlor and the trust instrument provides that the trustee shall pay income or principal or both for the education or support of the beneficiary or gives the trustee discretion to determine the amount of income or principal or both to be paid to or for the benefit of the settlor, a transferee or creditor of the settlor may reach the maximum amount that the trustee could pay to or for the benefit of the settlor under the trust instrument, not exceeding the amount of the settlor’s proportionate contribution to the trust. (c) For purposes of this chapter, the settlor shall not be considered to be a beneficiary of an irrevocable trust created by the settlor solely by reason of a discretionary authority vested in the trustee to pay directly or reimburse the settlor for any federal or state income tax on trust income or principal that is payable by the settlor, and a transferee or creditor of the settlor shall not be entitled to reach any amount solely by a reason of that discretionary authority.