samples/ContravariantReturns.java

/*
 * Copyright 2020 The JSpecify Authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

@NullMarked
interface ContravariantReturns {
  Object makeObject();

  Lib<? extends Object> makeImplicitlyObjectBounded();

  Lib<? extends Object> makeExplicitlyObjectBounded();

  interface Subtype extends ContravariantReturns {
    @Override
    // jspecify_nullness_mismatch
    @Nullable Object makeObject();

    @Override
    // jspecify_nullness_mismatch
    Lib<?> makeImplicitlyObjectBounded();

    @Override
    // jspecify_nullness_mismatch
    Lib<? extends @Nullable Object> makeExplicitlyObjectBounded();
  }

  interface Lib<T extends @Nullable Object> {}
}