[lworld] RFR: 8327695: [lworld] javac can generate incorrect code in inner class' constructors

[Vicente Romero]

When dealing with value classes javac, as mandated by the spec, is placing field initializers before any invocation to `super()`. This works just fine most of the time but for cases like:

class JavacBug {
    value class V1 {}

    value class V2 {
        V1 v = new V1();
    }

    void test() {
        V2 v2 = new V2();
    }

    public static void main(String... args) {
        JavacBug jb = new JavacBug();
        jb.test();
    }
}

javac is generating incorrect code for class V2 due to a getfield being generated to read the synthetic field storing the outer this before invoking the constructor for V1. The proposed change is changing the generated bytecode to read the outer this from the mandated parameter javac adds to inner class constructors,

TIA

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Commit messages:
 - 8327695: [lworld] javac can generate incorrect code in inner class' constructors

Changes: https://git.openjdk.org/valhalla/pull/1048/files
  Webrev: https://webrevs.openjdk.org/?repo=valhalla&pr=1048&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8327695
  Stats: 59 lines in 4 files changed: 53 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/valhalla/pull/1048.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1048/head:pull/1048

PR: https://git.openjdk.org/valhalla/pull/1048