TestOpt.java

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

/** Test class org.checkerframework.checker.nullness.Opt. */
// @below-java8-jdk-skip-test
class TestOpt {
    void foo1(@Nullable Object p) {
        if (Opt.isPresent(p)) {
            p.toString(); // Flow refinement
        }
    }

    void foo1b(@Nullable Object p) {
        if (!Opt.isPresent(p)) {
            //:: error: (dereference.of.nullable)
            p.toString();
        }
    }

    void foo2(@Nullable Object p) {
        Opt.ifPresent(p, x -> System.out.println("Got: " + x));
    }

    void foo2b(@Nullable Object p) {
        Opt.ifPresent(p, x -> System.out.println("Got: " + x.toString()));
    }

    void foo3(@Nullable Object p) {
        Object o = Opt.filter(p, x -> x.hashCode() > 10);
    }

    void foo4(@Nullable Object p) {
        String s = Opt.map(p, x -> x.toString());
    }

    void foo4b(@Nullable Object p) {
        //:: error: (argument.type.incompatible)
        String s = Opt.map(p, null);
    }

    void foo5(@Nullable Object p) {
        @NonNull Object o = Opt.orElse(p, new Object());
    }

    void foo5b(@Nullable Object p) {
        //:: error: (argument.type.incompatible)
        @NonNull Object o = Opt.orElse(p, null);
    }

    void foo6(@Nullable Object p) {
        @NonNull Object o = Opt.orElseGet(p, () -> new Object());
    }

    void foo6b(@Nullable Object p) {
        //:: error: (return.type.incompatible)
        @NonNull Object o = Opt.orElseGet(p, () -> null);
    }

    void foo7(@Nullable Object p) {
        try {
            @NonNull Object o = Opt.orElseThrow(p, () -> new Throwable());
        } catch (Throwable t) {
            // p was null
        }
    }

    void foo7b(@Nullable Object p) {
        try {
            //:: error: (return.type.incompatible)
            @NonNull Object o = Opt.orElseThrow(p, () -> null);
        } catch (Throwable t) {
            // p was null
        }
    }
}