import java.util.HashMap;
import java.util.Map;
import org.checkerframework.checker.nullness.qual.KeyFor;
import org.checkerframework.checker.nullness.qual.NonNull;
import org.checkerframework.checker.nullness.qual.Nullable;

public class MapGetNullable {

    void foo0(Map<String, @Nullable Integer> m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key);
    }

    <K, V> V get0(Map<K, V> m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    public static class MyMap1<K, V> extends HashMap<K, V> {
        // TODO: These test cases do not work yet, because of the generic types.
        // void useget(@KeyFor("this") String k) {
        //     V val = get(k);
        // }
        // void useget2(@KeyFor("this") String k) {
        //     V val = this.get(k);
        // }
    }

    void foo1(MyMap1<String, @Nullable Integer> m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key);
    }

    <K, V> V get1(MyMap1<K, V> m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    public static class MyMap2<V, K> extends HashMap<K, V> {}

    void foo2(MyMap2<@Nullable Integer, String> m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key);
    }

    <K, V> V get2(MyMap2<V, K> m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    public static class MyMap3<K> extends HashMap<K, @Nullable Integer> {}

    void foo3(MyMap3<String> m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key);
    }

    <K> @Nullable Integer get3(MyMap3<K> m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    public static class MyMap4<K> extends HashMap<K, Integer> {}

    void foo4(MyMap4<String> m, @KeyFor("#1") String key) {
        Integer val = m.get(key);
    }

    <K> Integer get4(MyMap4<K> m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    public static class MyMap5<V> extends HashMap<String, V> {}

    void foo5(MyMap5<@Nullable Integer> m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key);
    }

    <V> V get5(MyMap5<V> m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    public static class MyMap6 extends HashMap<String, Integer> {
        void useget(@KeyFor("this") String k) {
            @NonNull Integer val = get(k);
        }

        void useget2(@KeyFor("this") String k) {
            @NonNull Integer val = this.get(k);
        }
    }

    void foo6(MyMap6 m, @KeyFor("#1") String key) {
        @NonNull Integer val = m.get(key);
    }

    Integer get6(MyMap6 m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    public static class MyMap7 extends HashMap<String, @Nullable Integer> {
        void useget(@KeyFor("this") String k) {
            // :: error: (assignment.type.incompatible)
            @NonNull Integer val = get(k);
        }

        void useget2(@KeyFor("this") String k) {
            // :: error: (assignment.type.incompatible)
            @NonNull Integer val = this.get(k);
        }
    }

    void foo7(MyMap7 m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key);
    }

    Integer get7(MyMap7 m, @KeyFor("#1") String key) {
        // :: error: (return.type.incompatible)
        return m.get(key);
    }

    // MyMap9 ensures that no changes are made to the return type of overloaded versions of get().

    public static class MyMap9<K, V> extends HashMap<K, V> {
        @Nullable V get(@Nullable Object key, int itIsOverloaded) {
            return null;
        }
    }

    void foo9(MyMap9<String, @Nullable Integer> m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key);
    }

    void foo9a(MyMap9<String, @Nullable Integer> m, @KeyFor("#1") String key) {
        // :: error: (assignment.type.incompatible)
        @NonNull Integer val = m.get(key, 22);
    }

    <K, V> V get9(MyMap9<K, V> m, @KeyFor("#1") String key) {
        return m.get(key);
    }

    <K, V> V get9a(MyMap9<K, V> m, @KeyFor("#1") String key) {
        // :: error: (return.type.incompatible)
        return m.get(key, 22);
    }
}