test/langtools/tools/javac/generics/6294779/T6294779c.java

/*
 * @test    /nodynamiccopyright/
 * @bug     6294779
 * @summary Problem with interface inheritance and covariant return types
 * @author  Maurizio Cimadamore
 * @compile/fail/ref=T6294779c.out -XDrawDiagnostics  T6294779c.java
 */

public class T6294779c<X> {

    interface A {}

    interface B {}

    interface C {}

    interface I1 {
        T6294779c<? extends A> get();
    }

    interface I2 {
        T6294779c<? extends B> get();
    }

    interface I3 {
        T6294779c<? extends C> get();
    }

    interface I4 extends I1, I2, I3 {}
}