A DESCRIPTION OF THE PROBLEM :
The following example does not compile. If we explicitly define the type of variable x, then it works.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
javac Cls.java

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Compile successfully
ACTUAL -
Cls.java:23: error: incompatible types: Cls4<CAP#1> cannot be converted to Cls4<? extends Cls3<Float>>
    return x;
           ^
  where CAP#1 is a fresh type-variable:
    CAP#1 extends Cls3<? super Float> from capture of ?
1 error

---------- BEGIN SOURCE ----------
abstract class Cls<T1> {
  public Cls() {}
}

abstract class Cls2<T2> extends Cls<T2> {
  public Cls2() {}
}

abstract class Cls3<T3 extends Float> extends Cls2<T3> {
  public Cls3() {}
}

abstract class Cls4<T4 extends Cls3<? super Float>> {
  public Cls4() {}
}

final class Cls5 {
  public Cls5() {}
  public final Cls4<? extends Cls3<Float>> foo() {
    Cls4<? extends Cls3<Float>> y = (Cls4<? extends Cls3<Float>>) null;
    var x = y;
    // Cls4<? extends Cls3<Float>> x = y; // This works
    return x;
  }
}
---------- END SOURCE ----------

FREQUENCY : always