This is a code question and I live in the US.
Some background. My house originally had no overhead lights except for the bathrooms, kitchen and hallways. The rest of the rooms had just one switched receptacle, usually in the most inconvenient spot to put a floor lamp. The house has two circuits for the non-switched receptacles and two circuits for the switched receptacles and overhead lights. I've since rewired all the rooms with overhead lights and most of the switched receptacles I've converted to non-switched.
Now the code question. Is there any code violations converting a switched receptacle on a lighting circuit to a non switched receptacle? Or Similar, could someone add a receptacle to a lighting circuit and still be under code.