test262 class tail — ~211 language/statements + expressions class fails

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The largest language gap. language/statements/class = 211 fails (+ a parallel cluster in language/expressions/class).

Reasons (statements)

• 45× Expected a ReferenceError (TDZ / binding-resolution in class bodies)
• 37× Expected a TypeError (missed validation negatives)
• 19× async class-method test failures
• 12× (no output), 11× missed-negatives

Likely areas

Class static/instance field TDZ, private-field brand checks, super edge cases, async-generator methods, decorator-adjacent semantics. Deep semantics — diminishing returns per fix, but the single biggest language bucket.

Measure: scripts/test262_subset.py --dir language/statements/class language/expressions/class (node v26).

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Status update (2026-06-18)

Progress on the class tail since this was filed:

• fix(class): super-in-static resolution + accessor .name reflection (#5345) #5395 merged — super-in-static resolution + accessor .name reflection.
• codegen: derived-ctor this-TDZ on standalone constructor-symbol path (toward #5345) #5362 merged — derived-constructor this-TDZ on the standalone constructor-symbol path.

No class-tail PR is currently in flight.

Remaining, unchanged:

• Expected a ReferenceError 45 — TDZ / binding-resolution in class bodies
• Expected a TypeError 37 — missed validation negatives
• async class-method failures (19), private-field brand checks, super edge cases, async-generator methods, decorator-adjacent semantics

Deep semantics with diminishing returns per fix, but the single biggest language bucket. Keeping open as the class tracker; authoritative numbers from scripts/test262_subset.py --dir language/statements/class language/expressions/class.

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Re-measured the class tail (scripts/test262_subset.py --dir language/statements/class language/expressions/class --jobs 7, test262 4249661): parity 95.0% — 5099 pass, 56 diff, 199 runtime-fail, 16 compile-fail.

Opened #5508 for one concrete cluster from the compile-fail bucket: duplicate static field names (static f = …; static f = …;) emitted a redefined @perry_static_…__C__f LLVM global, so clang rejected the whole module. That sank elements/static-field-redeclaration and contributed to static-init-sequence. Fixed by deduping the defining-global emission while still running every initializer in order; added a parity gap test.

Remaining buckets (unchanged, deep semantics):

• runtime-fail 199 — top reasons: Expected a TypeError … not thrown (29, missed validation negatives), value is not a function (12), TDZ Expected a ReferenceError (5+), private brand-check negatives, async-method ordering.
• compile-fail 16 — also: SWC parse rejections of valid grammar (grammar-static-ctor-*-valid, class x extends x TDZ), name-binding/in-extends-expression* codegen.
• Note: static-init-sequence needs interleaved field/static-block ordering (currently all fields then all blocks) — a separate, larger change, not in fix(codegen): #5345 — dedup duplicate static-field LLVM global emission #5508.