RFR: Add alternate desugaring strategy for null-restricted arrays

[Maurizio Cimadamore]

On Fri, 9 Jan 2026 16:11:11 GMT, Maurizio Cimadamore <mcimadamore at openjdk.org> wrote:

> Creation of null-restricted arrays are desugared as calls into methods of the `ArrayCreation` class, as we need to set the "strict" marker on the created array.
> Currently the JVM doesn't support creation of null-restricted array for non-value types, so in this PR I cleaned up the `ArrayCreation` API to reflect more what javac needs. Also, according to our long term plans, `ArrayCreation` is really implemented on top of a new primitive in `Array`, which will be refined later to support creation of arrays with desired flags.
> 
> The translation strategy in javac is simple -- given an array initializer `{ .. }`, we just assign the initializer to a temp variable, then wrap the initializer using a call to `ArrayCreation::copied` to obtain the new array. Then we wrap everything in a let expression, so that things compose nicely.
> 
> While writing the test I realized that our combo framework failed to report compilation and execution failures. As I fixed that issue, I realized that a test I've added (`NullRestrictionReflectiveTest`) was not working correctly, as it had compilaton issues with some of the combinations and even a latent issue in signature parsing which I have now fixed.

src/java.base/share/classes/sun/reflect/generics/parser/SignatureParser.java line 600:

> 598:             case 'Z':
> 599:             case 'L':
> 600:             case '!':

This fix is unrelated to this PR, but necessary to fix `NullRestrictionReflectiveTest`

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PR Review Comment: https://git.openjdk.org/valhalla/pull/1877#discussion_r2676772006