TypeScript Diagnostic Reachability

Generated by node scripts/gen-ts-reachability.mjs. Do not hand-edit.

Splits the non-emitted rows of TS_DIAGNOSTIC_CODE_STATUS.md into active parity targets the reference compiler (typescript-go) actually references in live source, known blocked/effectively-dead references, and codes present only in the upstream message table that tsgo never emits (dead — obsolete wording, test-only fixtures, or classic-tsc-only).

Faithful parity = emit the active parity-target set. Dead and effectively-dead codes correctly stay non-emitted; emitting them would diverge from the reference compiler.

Summary

Reachable worklist by range

Blocked/effectively-dead references

These codes have production-looking tsgo references, but the reachable consumer path is currently dead or subsystem-gated. They stay non-emitted until the reference compiler grows a live emission path.

• TS1059 A_promise_must_have_a_then_method_1059 — Referenced only from the low-level promised-type helper. Modern awaited-type callers probe that helper without an error node, then emit wrapper diagnostics such as TS1058 or TS1320 instead.
• TS1060 The_first_parameter_of_the_then_method_of_a_promise_must_be_a_callback_1060 — Referenced only from the low-level promised-type helper. Modern awaited-type callers probe that helper without an error node, then emit wrapper diagnostics such as TS1058 or TS1320 instead.
• TS5078 Unknown_watch_option_0_5078 — Referenced only from watchOptionsDidYouMeanDiagnostics; tsgo's JSON watchOptions parser is commented out, so the live path uses TS5080 instead.
• TS5079 Unknown_watch_option_0_Did_you_mean_1_5079 — Referenced only from watchOptionsDidYouMeanDiagnostics; tsgo's JSON watchOptions parser is commented out, so the live path uses TS5080 instead.

Notes: heuristic false-positives & subsystem-gated clusters

Confirm against this list before picking one:

• Effectively dead despite a JSX precondition reference — TS2602 is still referenced by checkJsxPreconditions, but tsgo's getJsxElementTypeAt currently returns errorType rather than nil for a missing JSX.Element, so the nil-check never fires. Observable no-namespace JSX cases emit TS7026 instead.
• tsc --build mode (not yet in Home) — TS5072 / TS5073 / TS5077 (build-option parse errors) and TS5093 / TS5094 (--build-only vs non---build option gating) require the project-references build orchestrator. Implement tsc -b before these.

Dead in tsgo (faithfully non-emitted)

455 codes. Listed for auditability; none should be emitted unless a production tsgo reference appears.