[cknitt]

Fixes #8973.

runtime_tag_of_parsetree accepts float and bigint @as payloads (@as(1.5), @as(12n)), but the error for any other payload left them out:

A variant case annotation @as(...) must be a string, integer, float, bigint, boolean, null, or undefined.

compiler/ml/UntaggedVariants.md quotes the message, so it is updated too. In the same document, the rule 6 table now notes that for arrays and tuples the code prints "an array or tuple type" rather than "a C type".

Tests

The snapshot of UntaggedInvalidVariantAsAnnotation.res is updated.

🤖 Generated with Claude Code

https://claude.ai/code/session_01Xk6AeCYpCK4SZRtHYKHGoe

[github-actions]

Semantic Diff

1 commit · Full page

List float and bigint in the error for an invalid @as payload

_{2f2d098 · Christoph Knittel with Claude Opus 5.5 · Oct 23, 2026}

Why

@as accepts float and bigint literals, but the error for any other payload listed only strings, integers, booleans, null and undefined. The untagged variants spec, which quotes the message, now matches it, and its rule 6 table gives the wording printed for arrays and tuples.

Diagnostic modified (invalid @as payload)

type t = | @as(foo) A | B

diagnostic

-A variant case annotation @as(...) must be a string, integer, boolean, null, or undefined.
+A variant case annotation @as(...) must be a string, integer, float, bigint, boolean, null, or undefined.

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commit: 2f2d098

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Developer playground preview: https://rescript-lang.github.io/rescript/dev-playground/?version=pr-8987

[cknitt]

@codex review

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-23T09:30:57.293219Z	2f2d098	Manual request

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Codex Review: Didn't find any major issues. Breezy!

Reviewed commit: 2f2d098ad2

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