Check the C172 manual under EMERGENCY PROCEDURES.
Some models contain a caution/warning against slipping with 30 degrees
of flaps.

xyzzy wrote:
There is no "slip with flaps" or not controversy in a low-wing plane.

Matt Whiting wrote:
What controversy? You can do it if it isn't prohibilted. I don't know
about all Cessna models, but I don't think that all have this prohibition.

Newps wrote:
None do.