LazyInitialization.java

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

public class LazyInitialization {
    @Nullable Object nullable;
    @NonNull Object nonnull;
    @MonotonicNonNull Object lazy;
    @MonotonicNonNull Object lazy2 = null;
    final @Nullable Object lazy3;

    public LazyInitialization(@Nullable Object arg) {
        lazy3 = arg;
        nonnull = new Object();
    }

    void randomMethod() {}

    void testAssignment() {
        lazy = "m";
        //:: error: (assignment.type.incompatible)
        lazy = null; // null
    }

    void testLazyBeingNull() {
        //:: error: (dereference.of.nullable)
        nullable.toString(); // error
        nonnull.toString();
        //:: error: (dereference.of.nullable)
        lazy.toString(); // error
        //:: error: (dereference.of.nullable)
        lazy3.toString(); // error
    }

    void testAfterInvocation() {
        nullable = "m";
        nonnull = "m";
        lazy = "m";
        if (lazy3 == null) {
            return;
        }

        randomMethod();

        //:: error: (dereference.of.nullable)
        nullable.toString(); // error
        nonnull.toString();
        lazy.toString();
        lazy3.toString();
    }

    private double @MonotonicNonNull [] intersect;

    public void check_modified(double[] a, int count) {
        if (intersect != null) {
            double @NonNull [] nnda = intersect;
        }
    }

    class PptRelation1 {
        public void init_hierarchy_new(PptTopLevel ppt, Object eq) {
            ppt.equality_view = eq;
            ppt.equality_view.toString();
        }
    }

    class PptTopLevel {
        public @MonotonicNonNull Object equality_view;
    }

    class PptRelation1b {
        // This is the same code as in PptRelation1, but comes after the class
        // declaration of PptTopLevel. This works as expected.
        public void init_hierarchy_new(PptTopLevel ppt, Object eq) {
            ppt.equality_view = eq;
            ppt.equality_view.toString();
        }
    }

    class PptRelation2 {
        public @MonotonicNonNull Object equality_view2;

        public void init_hierarchy_new(PptRelation2 pr1, PptRelation2 pr2, Object eq) {
            //:: error: (dereference.of.nullable)
            pr1.equality_view2.toString();

            pr1.equality_view2 = eq;
            pr1.equality_view2.toString();

            //:: error: (dereference.of.nullable)
            pr2.equality_view2.toString();
            //:: error: (dereference.of.nullable)
            this.equality_view2.toString();

            pr2.equality_view2 = eq;
            pr2.equality_view2.toString();

            this.equality_view2 = eq;
            this.equality_view2.toString();
        }
    }
}