Android Studio and Kotlin: Unresolved reference: also

I tried everything possible and nothing worked. The only solution for me was to delete .AndroidStudio folder from C:/Users/YourName/. Android Studio resets and everything works as it should.

The also function was added in Kotlin 1.1 but you have your Language version set to 1.0. Go to your settings/preferences and change the Kotlin version to 1.1.