CoroutineScope.coroutineContext deprecated, how do I do it now?

Are you by any chance using kotlin 1.3-M1? Because they are moving coroutiens out of the experimental package. There are some steps that need to be done for migration and calling code still compiled with the old experimental coroutines.
I can’t really tell you more because I did not yet try out the preview build of 1.3 myself. More info is here though: