Problems inferring arguments from stream pipelines

[jpschewe]

With checker version 3.48.3. Java version 21.0.5. I'm executing the checker org.checkerframework.checker.nullness.NullnessChecker.

Shouldn't NonNull satisfy a PolyNull requirement?

package net.mtu.eggplant.checker;

import java.util.List;
import java.util.function.Predicate;
import java.util.stream.Stream;

import org.checkerframework.checker.nullness.qual.Nullable;

public class StreamTypeArguments {

  static abstract class GoalElement {
    public abstract boolean isGoal();
  }

  static abstract class AbstractGoal extends GoalElement {
    @Override
    public boolean isGoal() { return true; }

    public abstract boolean isComputed();
  }

  static class Goal extends AbstractGoal {
    @Override
    public boolean isComputed() { return false; }

    public boolean isRequired() { return true; }
  }

  static class ComputedGoal extends AbstractGoal {
    @Override
    public boolean isComputed() { return true; }
  }
  
  
  public static void function(final List<GoalElement> goalElements) {

    final boolean somethingRequired = goalElements.stream()//
      .filter(GoalElement::isGoal)//
      .map(AbstractGoal.class::cast)//
      .filter(Predicate.not(AbstractGoal::isComputed)) //
      .map(Goal.class::cast)//
      .anyMatch(Goal::isRequired);
  }
  
  
}

/home/jpschewe/projects/checker-bugs/src/main/java/net/mtu/eggplant/checker/StreamTypeArguments.java:40: error: [type.arguments.not.inferred] Could not infer type arguments for Predicate.not
      .filter(Predicate.not(AbstractGoal::isComputed)) //
                           ^
  unsatisfiable constraint: @Initialized @PolyNull AbstractGoal <: @Initialized @NonNull AbstractGoal
/home/jpschewe/projects/checker-bugs/src/main/java/net/mtu/eggplant/checker/StreamTypeArguments.java:42: error: [methodref.receiver] Incompatible receiver type
      .anyMatch(Goal::isRequired);
                ^
  found   : @Initialized @NonNull Goal
  required: @Initialized @PolyNull Goal
  Consequence: method in @Initialized @NonNull Goal
    @Initialized @NonNull boolean isRequired(@Initialized @NonNull Goal this)
  is not a valid method reference for method in @Initialized @NonNull Predicate<@Initialized @PolyNull Goal>
    @Initialized @NonNull boolean test(@Initialized @NonNull Predicate<@Initialized @PolyNull Goal> this, @Initialized @PolyNull Goal p0)