[lworld] RFR: 8369062: [lworld] Do not allow references to instance fields before a this() invocation

[Chen Liang]

On Sat, 4 Oct 2025 02:40:02 GMT, Vicente Romero <vromero at openjdk.org> wrote:

> implementation of [1] in valhalla. This means that code like:
> 
> class Inner7 {
>     private int x;
> 
>     public Inner7(byte y) {
>         x = y;  // error can't refer to an instance field before a this() invocation
>         this((int)y);
>     }
>     public Inner7(int x) {
>         this.x = x;
>         super();
>     }
> }
> 
> 
> won't be accepted by javac
> [1] https://bugs.openjdk.org/browse/JDK-8368719

Comment in JDK-8368719 says we don't want error unless JEP 401 is previewed and compilation is done with preview enabled. I think what we have (failing for pre-this immediately without preview on) is probably better, but we just need to make sure Dan or whoever is aware of our decisions.

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PR Comment: https://git.openjdk.org/valhalla/pull/1659#issuecomment-3367924462