Vector API can be value classes!

[liach]

Testing: Build JDK, run jshell with --add-modules jdk.incubator.vector --enable-preview, and run this:

import module jdk.incubator.vector;
IntVector.class.isValue()

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Update a local copy of the PR:
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$ git pr checkout 32113

View PR using the GUI difftool:
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https://git.openjdk.org/jdk/pull/32113.diff

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[wenshao]

⚠️ Downgraded from Approve to Comment: CI failing: Pre-submit tests - windows-aarch64 / test - Test (tier1), Pre-submit tests - linux-cross-compile / build - Build / test, jcheck-openjdk/jdk-32113. Reviewed.

— qwen3.8-max-preview via Qwen Code /review

[ExE-Boss]

Note that the lworld+vector branch also has changes to VectorSupport to include a multi‑field‑based approach¹, thus avoiding identity issues caused by the use of arrays.

Footnotes

1. Which act like fixed‑size frozen value arrays (as in frozen arrays that are values) ↩

[ExE-Boss]

This probably should do the this.payload assignment before the super() call, even when preview features are disabled:

Suggested change

	public VectorPayload(Object payload) {
	this.payload = payload;
	super();
	}