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  1. JDK
  2. JDK-8274848

LambdaMetaFactory::metafactory on REF_invokeSpecial impl method has incorrect behavior

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        Reported on https://mail.openjdk.java.net/pipermail/jdk-dev/2021-October/006099.html

        This is to follow up the behavorial change on LambdaMetaFactory::metafactory when the implementation is REF_invokeSpecial method handle on a public/protected method in the target class. This won't happen for classes compiled from javac since REF_invokeSpecial method handle is generated when the method is a private method whereas REF_invokeVirtual method handle would be generated on a public/protected.

        To reproduce:
        1. compile it with java 8
        2. modify the access of testPrivate from private to public in .class file (do not modify any invokespecial and ref_invokespecial).
        3. Java 14 without JEP 371, the method reference `this::testPrivate` with REF_invokeSpecial kind will be resolved to ExampleClass::testPrivate on a receiver of type ExampleClass$SubClass. With JEP 371 change, the method reference `test::testPrivate` with REF_invokeSpecial kind will be resolved to ExampleClass$Subclass::testPrivate instead.


        import java.util.function.Supplier;

        public class ExampleClass {
            public static void main(String[] args) {
                System.out.println(new SubClass().test());
                System.out.println(new SubClass().testWithLMF());
            }

            public String test() {
                return this.testPrivate();
            }

            public String testWithLMF() {
                Supplier<String> supplier = this::testPrivate;
                return supplier.get();
            }

            private String testPrivate() {
                return "123";
            }

            public static class SubClass extends ExampleClass {
                public String testPrivate() {
                    return "456";
                }
            }
        }

        Java 14:

        $ java ExampleClass
        123
        123

        Java 15:

        $ java ExampleClass
        123
        456

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                Assignee:
                mchung Mandy Chung
                Reporter:
                mchung Mandy Chung
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                  Updated:
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