Ceylon Structural Typing and JVM Interoperability Constraints

Ceylon implements structural typing, enabling type compatibility based on member signatures rather than explicit inheritance hierarchies. This allows for flexible interface implementation without requiring a class to explicitly declare its adherence to a specific type.

When targeting the Java Virtual Machine (JVM), the compiler must map these structural requirements to a platform that primarily relies on nominal typing. There is uncertainty regarding how the compiler maintains type safety and performance when a structural type is passed across the boundary to a Java-based library that expects a nominal interface.

• How does the Ceylon compiler resolve structural type compatibility when interacting with Java bytecode that lacks equivalent structural metadata?
• What are the performance implications of the runtime checks required to verify structural compatibility during JVM execution?