NEC 410-4 Lighting installed in and over tubs and showers must be suitable for wet locations.No cord connected, hanging or pendant within the 3ft horizontal and 8 ft vertical area above the tub. Most recess lighting fixtures have a shower trim or cover that when properly installed to manufacturers specifications meet the requirments for this location. Check with the manufacturer in all cases dont assume. In particular both Halo & Juno have 2 versions of shower trims (plastic and METAL) although both seem to permited I would advise going with the plastic version for both added safety and durability. Seems odd though, imagine someone showering..poof the lamp goes out..grab a towel..grab a bulb.. leave the switch on...... My other favorite is wall sconces over the tub area....Yah no intelligent person would or would they??