From what I've learned (here), the trap arm needs to be 1.5x the (largest??) trap diameter. If the tail pipe (1.25") piece dumps into a 1.5" p-trap, the trap arm would need to be at "least" 3", beginning at the trap weir?
Question is, does that 3" need to be exposed? (in other words if the trap weir begins, near or at, the back of the vanity and extends 3"+ into the wall cavity, is that to "code"
Question is, does that 3" need to be exposed? (in other words if the trap weir begins, near or at, the back of the vanity and extends 3"+ into the wall cavity, is that to "code"