test/langtools/tools/javac/lambda/LambdaReturnUnboxing.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug 8203338
 * @summary Unboxing in return from lambda miscompiled to throw ClassCastException
 */

import java.util.*;

public class LambdaReturnUnboxing {
    interface C {
        Character get(Character c);
    }
    static <T> T c(T t, int... i) { return t; }

    static Character d() { return List.of('d').get(0); }

    public static void main(String... args) {
        List.of('x', 'y').stream().max((a, b) -> List.of(a).get(0));
        List.of('x', 'y').stream().max((a, b) -> { return List.of(a).get(0); });

        C c = LambdaReturnUnboxing::c;
        int i = c.get('c');

        i = d();
    }
}