A DESCRIPTION OF THE PROBLEM :
It appears `javac` emits a duplicate `checkcast` for the first bound of an intersection type as part of a cast expression.

Possibly related to JDK-8011392

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Compile the class IntersectionTypeTest provided below
2. Decompile the class file with `javap -v`
3. Look at the byte code for method `test2`

ACTUAL -
         1: checkcast #9 // class IntersectionTypeTest$C1
         4: checkcast #7 // class IntersectionTypeTest$I1
         7: checkcast #9 // class IntersectionTypeTest$C1

---------- BEGIN SOURCE ----------
class IntersectionTypeTest {
    interface I1 { }
    static class C1 { }
    
    static Object test(Object o) {
        // As expected: Single checkcast I1
        return (I1) o;
    }
    
    static Object test2(Object o) {
        // Unexpected: Duplicate checkcast C1
        return (C1 & I1) o;
    }
}
---------- END SOURCE ----------