test262 intl402 (Intl/ECMA-402) at 78% — 549 fails (not 'out of scope')

[proggeramlug]

Summary

The hardcoded # Intl — out of scope (no ICU) skip is stale — Perry scores 1,925/2,474 = 78% on intl402 against the node v26 oracle. 549 real fails remain.

Breakdown by constructor

• 250 Temporal (intl402/Temporal — Temporal's locale formatting / toLocaleString Intl integration) — biggest chunk
• 113 DateTimeFormat, 50 NumberFormat, 36 Intl (top-level), 31 PluralRules, 27 Collator, 8 String, 7 DurationFormat, …

Dominant reasons

• 84× TypeError: Insufficient fields + 24× fields cannot be empty (Temporal/Intl field resolution)
• 34× formatToParts is not a function (DateTimeFormat/NumberFormat formatToParts unimplemented)
• 23× getCanonicalLocales is not a function (Intl.getCanonicalLocales missing)
• 22× undefined is not a constructor (a missing Intl constructor)
• 16× Cannot convert undefined or null to object

Scope to close

Highest ROI: (1) Temporal↔Intl toLocaleString field resolution (250), (2) formatToParts on DateTimeFormat/NumberFormat (34), (3) Intl.getCanonicalLocales (23), (4) the missing constructor(s).

Measurement

scripts/test262_subset.py --dir intl402 --all-features (intl402 path-skipped + Intl features absent from features-applicable.txt). node v26 oracle.

[proggeramlug]

Closed by #5320 (feat(intl): getCanonicalLocales, supportedValuesOf, formatToParts + ListFormat/RelativeTimeFormat/PluralRules), merged to main. Largest intl402 clusters addressed; re-sweep will quantify the remaining tail (Temporal↔Intl field resolution, ICU-locale-data-variant cases).