[GROOVY-10380] SC: IncompatibleClassChangeError when calling interface default method from non-public interface

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 4.0.0-rc-1, 3.0.20
• Component/s: Static compilation
• Labels: default-methods
• Assignee: Eric Milles
• Reporter: Eric Milles
• Created: 23/Nov/21 18:43
• Updated: 11/Dec/23 22:04
• Resolved: 26/Nov/21 18:20

Description

Consider the following:

package p;
interface I {
  default void m() {
    System.out.println("works");
  }
}
public abstract class A implements I { // or concrete or implemented in groovy
}

// not in package p
@groovy.transform.CompileStatic // works if CompileDynamic or TypeChecked
class C extends p.A {
  void test() {
    m() // IncompatibleClassChangeError: Found class C, but interface was expected
  }
}

In the case of a non-public interface with a public default method, static compilation produces a runtime error that is not present for dynamic groovy or java.