New Flutter project in Intellij Ultimate says "Kotlin: Unresolved reference: embedding"

When I create a new Flutter project, either via the command line or via Intellij, the demo app runs fine on my android phone, whether I run it from the command line or from Intellij. However, when I rebuild the project in Intellij Ultimate, the class MainActivity has an unresolved import

import io.flutter.embedding.android.FlutterActivity

It says "Kotlin: Unresolved reference: embedding". Same when I create the project for Java.