- scr_intl.c resolves the default locale as V8 does: ICU's POSIX locale
(LC_ALL=C, C.UTF-8, POSIX) becomes en-US, so numbers keep their grouping
separators, and other defaults round-trip through their BCP 47 tag. The
number formatter, the date pattern generator, the date formatter and the
default word segmenter use that locale.
- The date formatter moves the Gregorian calendar's Julian cutover to the
start of ECMAScript time, so dates before October 1582 print their
proleptic Gregorian fields, as in Node.
- icu.numFormatDefault, icu.dateLocaleString and icu.dateLocaleTimeString
are in the may-throw set: a missing ICU data file throws an Error into the
surrounding catch.
- `x.toLocaleString(undefined)` reads the receiver before the argument runs.
- The linux-x64-gnu runtime pack ships the ICU headers scr_intl.c includes
beside its ICU archive (manifest `headers`, verified like the other
artifacts). The native compiler's sanitized build compiles scr_intl.c
against them and refuses with SC3003 when they are missing or changed.
The C-source path (sanitized builds) links the pack's ICU archive and
uses those headers, instead of building ICU with Zig's C++ driver.
- The macOS pack omits scr_intl.c, scr_intl.h declares ScrDyn, and the
library-mode teachings test uses a locale argument, which still refuses
with SC2020.
Corpus programs pin the C and C.UTF-8 locales, pre-1582 dates and the
receiver order against Node. intl-missing-data.test.ts covers the throw.
sanitizer.test.ts covers the header lookup.
