[GROOVY-11493] RuntimeError when implementing interfaces with conflicting default methods

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Duplicate
• Component/s: Static Type Checker

Language

groovy

• Assignee: Unassigned
• Reporter: Thodoris Sotiropoulos
• Created: 09/Oct/24 13:50
• Updated: 11/Oct/24 19:28
• Resolved: 11/Oct/24 19:28

Description

I have the following program

interface A {
  default void m() {
    System.out.println("here");
  }
}

interface B {
  default void m() {
    System.out.println("there")
  }
}

interface C extends B, A {}

class Test implements C {
  public void test() {
    this.m();
  }

  public static void main(String[] args) {
    Test x = new Test();
    x.test();
  }
} 

Actual behavior

The code compiles, but there's a runtime error

Exception in thread "main" java.lang.AbstractMethodError: Receiver class Test does not define or inherit an implementation of the resolved method 'void m()' of interface B.
        at Test.test(groovy109.groovy:17)
        at Test.main(groovy109.groovy:22)
 

Expected behavior

The code should have been rejected

Issue Links

• duplicates: GROOVY-10381 No compiler error for class that implements interfaces with duplicated default methods