tsz-conformance

name	tsz-conformance
description	Triage and maintain TSZ diagnostic conformance. Use when investigating conformance regressions, accepted-regression drift, fingerprint-only failures, issue creation from conformance data, or focused parity fixes that must preserve the conformance gate.

TSZ Conformance

Conformance is a regression gate. Prefer checked-in artifacts and narrow filters; CI owns broad runs.

Rules

• Read AGENTS.md and docs/plan/ROADMAP.md for conformance-affecting work.
• Do not run full conformance locally.
• Treat a failing test as a witness for a structural rule.
• Do not hide regressions with snapshot/allowlist churn.

Offline First

python3 scripts/conformance/query-conformance.py --dashboard
python3 scripts/conformance/query-conformance.py --campaigns
python3 scripts/conformance/query-conformance.py --fingerprint-only
python3 scripts/conformance/query-conformance.py --code TS2322
python3 scripts/conformance/query-conformance.py --code TS2322 --paths-only

Artifacts: conformance-detail.json, conformance-snapshot.json, conformance-accepted-regressions.txt, conformance-shard-weights.json.

Oracle

Semantics come from the pinned compiler, not from any other copy on the box. Run manual spot-checks through the wrapper so they match what the gate scores:

scripts/conformance/oracle.sh case.ts --strict --lib es2022 --target es2022
node scripts/node_modules/typescript/lib/tsc.js --version   # Version 7.0.2

• Use oracle.sh, not a bare tsc.js invocation. It runs the pinned typescript@7.0.2 with the same --singleThreaded --stableTypeOrdering true flags generate-tsc-cache.rs uses for TypeScript 7+. This is not just about ordering: typescript@7.0.2 (typescript-go) reports a different diagnostic set under --singleThreaded. A position-invalid import in a bare { } block (or if/loop/try body) gets TS2307/TS2305 only single-threaded, not under the default concurrent scheduler; the same import in a function, class static { }, or namespace body gets neither, in both modes (#16413). compare-to-parent.sh/conformance.sh score the single-threaded cache, so a plain tsc.js case.ts silently disagrees with the gate — hand-oracling without the flag reads a fix as passing that the gate then fails (this mis-scoped #16409/#16411).
• TypeScript/ (submodule) and any container-global /opt/**/node_modules/typescript are the 6.0 line. They are corpus and test cases only — never the source of a semantic rule.
• Reading a rule out of 6.0 source and pinning it with tests lands the wrong behaviour: #16215 encoded ignoreDeprecations !== "6.0" from a 6.0.2 typescript.js, but 7.0 removed that grace window entirely (#16217).
• 7.0 traps when hand-oracling: --target es5 was removed — it answers error TS5108 and emits nothing else, and that line carries no file.ts(l,c): prefix, so a row filter drops it and every row reads clean. strict also defaults to true.

Check raw output once before trusting a filtered sweep: an invalid invocation and a clean compile are indistinguishable after filtering.

Focused Run

./scripts/conformance/conformance.sh run --filter "<name>" --verbose

Keep filters precise. Let harnesses rebuild stale binaries when possible.

Triage

Classify: new/accepted/resolved/fingerprint-only/wrong-code/missing-code/ extra-code/crash/timeout/OOM. Then identify owner: relation, inference, narrowing, indexed/keyof/mapped/conditional/template, symbol resolution, diagnostic display, parser recovery, or emit-only.

Before coding, state the structural rule and adjacent cases. Behavior changes need owning-crate tests.

Accepted-regression drift: verify shard artifacts, update the accepted file only to match observed failing set, link/file issues for new accepts, and comment with numbers plus a provenance line.