From the IRC.
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SECTION P3201
- - FIXTURE TRAPS
- - - P3201.1 Design of traps.
Traps shall be of standard design, shall have smooth uniform internal waterways, shall be self-cleaning and shall not have interior partitions except where integral with the fixture. Traps shall be constructed of lead, cast iron, cast or drawn brass or approved plastic. Tubular brass traps shall be not less than No. 20 gage (0.8 mm) thickness. Solid connections, slip joints and couplings are permitted
to be used on the trap inlet, trap outlet, or within the trap seal. Slip joints shall be accessible.
I would not consider that as meeting "Slip joints shall be accessible."