Halva's @CaseClass, @CaseObject, @TypeAlias, and @ImplicitClass generate classes using the Java Annotation Processing tools. Depending on your development environment, you may need to enable annotation processing. Here are links to how to do this for commonly used development tools:
- IntelliJ IDEA
- Eclipse
- NetBeans
- Maven - should do this by default. If not, you can add an execution for it. Example Here.
- Gradle
Normally, Halva creates top level classes. However, you can change this. See details here regarding Type Containers.