RFR: 8349754: Invalid "early reference" error when class extends an outer class [v3]

Archie Cobbs acobbs at openjdk.org
Tue May 13 16:04:33 UTC 2025


> The compiler is generating a bogus error for this input:
> 
> $ cat Outer.java
> class Outer {
>     private int i;
>     class Sub extends Outer {
>         Sub() {
>             i = 42;
>             super();
>         }
>     }
> }
> $ javac --enable-preview --source 24 Outer.java
> Outer.java:5: error: cannot reference i before supertype constructor has been called
>             i = 42;
>             ^
> Note: Outer.java uses preview features of Java SE 24.
> Note: Recompile with -Xlint:preview for details.
> 1 error 
> 
> 
> The trick here is that the expression `i` refers to `Outer.this.i`, not `this.i`, but the error checking logic is mistakenly assuming the latter. This patch adds an exception for this case, which happens when the field is `private` and declared in a class which is both a superclass and an outer class.

Archie Cobbs has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains three commits:

 - Merge branch 'master' into JDK-8349754 to fix conflict.
 - Simplify logic using Symbol.isMemberOf() per review suggestion.
 - Fix incorrect "early reference" error.

-------------

Changes: https://git.openjdk.org/jdk/pull/23545/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23545&range=02
  Stats: 26 lines in 2 files changed: 20 ins; 0 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/23545.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23545/head:pull/23545

PR: https://git.openjdk.org/jdk/pull/23545


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