diff --git a/.agents/skills/testing-fixtures/SKILL.md b/.agents/skills/testing-fixtures/SKILL.md
index dbbad6ed..51be6c68 100644
--- a/.agents/skills/testing-fixtures/SKILL.md
+++ b/.agents/skills/testing-fixtures/SKILL.md
@@ -144,6 +144,27 @@ This generates two tests per case (pretty and non-pretty) and uses Jest snapshot
 3. Run `npx jest` to verify all tests pass
 4. Commit the `.sql` file, `generated.json`, and any new generated test files in `__tests__/kitchen-sink/`
 
+## PostgreSQL Regression Corpus (`__fixtures__/regress/`)
+
+A ratchet over the SQL that libpg_query vendors from PostgreSQL (`test/sql/postgres_regress`,
+`test/sql/plpgsql_regress`) plus its own test SQL (`test/sql/deparse*`, `test/plpgsql_samples.sql`):
+
+- `statements.json.gz`: unique parseable statements keyed like `generated.json`
+  (`postgres_regress/arrays-12.sql`), plus the libpg_query commit they came from. Built by
+  `cd packages/deparser && npm run fixtures:regress -- /path/to/libpg_query`. Check out the
+  `x-publish.libpgQueryCommit` of the pinned `libpg-query` release first.
+- `known-failures.deparser.json` / `known-failures.plpgsql-deparser.json`: statements that do not
+  round-trip yet.
+- Tests: `packages/deparser/__tests__/regress/regress-corpus.test.ts` (one test per source file,
+  pretty and non-pretty, via `TestUtils.expectAstMatch`) and
+  `packages/plpgsql-deparser/__tests__/regress-corpus.test.ts`. They run in the normal `test` script.
+
+A new failure fails the test, and so does a known failure that now passes. After fixing deparser
+bugs (or bumping `libpg-query` and regenerating the corpus), refresh the lists with
+`UPDATE_KNOWN_FAILURES=1 npx jest __tests__/regress` (deparser) and
+`UPDATE_KNOWN_FAILURES=1 npx jest __tests__/regress-corpus` (plpgsql-deparser), then review the diff.
+Bug fixes still get a kitchen-sink fixture; the corpus only guards against regressions.
+
 ## PL/pgSQL Fixtures (`plpgsql-deparser`)
 
 The PL/pgSQL deparser has its own fixture pipeline:
diff --git a/__fixtures__/regress/known-failures.deparser.json b/__fixtures__/regress/known-failures.deparser.json
new file mode 100644
index 00000000..763e43e3
--- /dev/null
+++ b/__fixtures__/regress/known-failures.deparser.json
@@ -0,0 +1,690 @@
+{
+  "deparse-depesz/08-selects.d/11-weird-operator.sql": [
+    "deparse-depesz/08-selects.d/11-weird-operator-1.sql"
+  ],
+  "deparse-depesz/19-transactions.d/02-rollback_and_chain.sql": [
+    "deparse-depesz/19-transactions.d/02-rollback_and_chain-1.sql"
+  ],
+  "deparse-depesz/19-transactions.d/04-commit_and_chain.sql": [
+    "deparse-depesz/19-transactions.d/04-commit_and_chain-1.sql"
+  ],
+  "postgres_regress/alter_generic.sql": [
+    "postgres_regress/alter_generic-237.sql",
+    "postgres_regress/alter_generic-238.sql",
+    "postgres_regress/alter_generic-243.sql",
+    "postgres_regress/alter_generic-244.sql",
+    "postgres_regress/alter_generic-245.sql",
+    "postgres_regress/alter_generic-252.sql",
+    "postgres_regress/alter_generic-253.sql",
+    "postgres_regress/alter_generic-261.sql",
+    "postgres_regress/alter_generic-262.sql",
+    "postgres_regress/alter_generic-314.sql",
+    "postgres_regress/alter_generic-323.sql"
+  ],
+  "postgres_regress/alter_operator.sql": [
+    "postgres_regress/alter_operator-21.sql"
+  ],
+  "postgres_regress/bit.sql": [
+    "postgres_regress/bit-17.sql",
+    "postgres_regress/bit-18.sql"
+  ],
+  "postgres_regress/collate.icu.utf8.sql": [
+    "postgres_regress/collate.icu.utf8-617.sql",
+    "postgres_regress/collate.icu.utf8-618.sql",
+    "postgres_regress/collate.icu.utf8-619.sql",
+    "postgres_regress/collate.icu.utf8-620.sql",
+    "postgres_regress/collate.icu.utf8-621.sql",
+    "postgres_regress/collate.icu.utf8-622.sql",
+    "postgres_regress/collate.icu.utf8-623.sql",
+    "postgres_regress/collate.icu.utf8-624.sql"
+  ],
+  "postgres_regress/collate.linux.utf8.sql": [
+    "postgres_regress/collate.linux.utf8-156.sql",
+    "postgres_regress/collate.linux.utf8-157.sql"
+  ],
+  "postgres_regress/collate.sql": [
+    "postgres_regress/collate-126.sql",
+    "postgres_regress/collate-143.sql"
+  ],
+  "postgres_regress/compression.sql": [
+    "postgres_regress/compression-17.sql"
+  ],
+  "postgres_regress/copy.sql": [
+    "postgres_regress/copy-22.sql"
+  ],
+  "postgres_regress/copy2.sql": [
+    "postgres_regress/copy2-106.sql"
+  ],
+  "postgres_regress/copyselect.sql": [
+    "postgres_regress/copyselect-18.sql",
+    "postgres_regress/copyselect-24.sql"
+  ],
+  "postgres_regress/database.sql": [
+    "postgres_regress/database-2.sql"
+  ],
+  "postgres_regress/domain.sql": [
+    "postgres_regress/domain-8.sql",
+    "postgres_regress/domain-17.sql",
+    "postgres_regress/domain-253.sql",
+    "postgres_regress/domain-287.sql",
+    "postgres_regress/domain-291.sql",
+    "postgres_regress/domain-293.sql"
+  ],
+  "postgres_regress/drop_if_exists.sql": [
+    "postgres_regress/drop_if_exists-158.sql",
+    "postgres_regress/drop_if_exists-159.sql",
+    "postgres_regress/drop_if_exists-160.sql",
+    "postgres_regress/drop_if_exists-161.sql"
+  ],
+  "postgres_regress/foreign_data.sql": [
+    "postgres_regress/foreign_data-77.sql",
+    "postgres_regress/foreign_data-216.sql",
+    "postgres_regress/foreign_data-237.sql",
+    "postgres_regress/foreign_data-295.sql",
+    "postgres_regress/foreign_data-493.sql"
+  ],
+  "postgres_regress/groupingsets.sql": [
+    "postgres_regress/groupingsets-188.sql"
+  ],
+  "postgres_regress/guc.sql": [
+    "postgres_regress/guc-135.sql",
+    "postgres_regress/guc-137.sql"
+  ],
+  "postgres_regress/index_including_gist.sql": [
+    "postgres_regress/index_including_gist-46.sql"
+  ],
+  "postgres_regress/index_including.sql": [
+    "postgres_regress/index_including-10.sql",
+    "postgres_regress/index_including-15.sql",
+    "postgres_regress/index_including-18.sql",
+    "postgres_regress/index_including-27.sql",
+    "postgres_regress/index_including-28.sql",
+    "postgres_regress/index_including-33.sql",
+    "postgres_regress/index_including-46.sql",
+    "postgres_regress/index_including-51.sql",
+    "postgres_regress/index_including-58.sql",
+    "postgres_regress/index_including-76.sql",
+    "postgres_regress/index_including-90.sql",
+    "postgres_regress/index_including-95.sql",
+    "postgres_regress/index_including-122.sql"
+  ],
+  "postgres_regress/limit.sql": [
+    "postgres_regress/limit-41.sql",
+    "postgres_regress/limit-69.sql",
+    "postgres_regress/limit-70.sql",
+    "postgres_regress/limit-71.sql",
+    "postgres_regress/limit-75.sql",
+    "postgres_regress/limit-78.sql"
+  ],
+  "postgres_regress/matview.sql": [
+    "postgres_regress/matview-162.sql",
+    "postgres_regress/matview-165.sql"
+  ],
+  "postgres_regress/misc.sql": [
+    "postgres_regress/misc-30.sql"
+  ],
+  "postgres_regress/namespace.sql": [
+    "postgres_regress/namespace-40.sql"
+  ],
+  "postgres_regress/numerology.sql": [
+    "postgres_regress/numerology-68.sql"
+  ],
+  "postgres_regress/object_address.sql": [
+    "postgres_regress/object_address-35.sql"
+  ],
+  "postgres_regress/plpgsql.sql": [
+    "postgres_regress/plpgsql-937.sql",
+    "postgres_regress/plpgsql-939.sql"
+  ],
+  "postgres_regress/privileges.sql": [
+    "postgres_regress/privileges-978.sql",
+    "postgres_regress/privileges-983.sql",
+    "postgres_regress/privileges-987.sql",
+    "postgres_regress/privileges-992.sql"
+  ],
+  "postgres_regress/reloptions.sql": [
+    "postgres_regress/reloptions-48.sql",
+    "postgres_regress/reloptions-58.sql"
+  ],
+  "postgres_regress/rules.sql": [
+    "postgres_regress/rules-481.sql",
+    "postgres_regress/rules-572.sql"
+  ],
+  "postgres_regress/sequence.sql": [
+    "postgres_regress/sequence-13.sql",
+    "postgres_regress/sequence-14.sql",
+    "postgres_regress/sequence-15.sql",
+    "postgres_regress/sequence-16.sql",
+    "postgres_regress/sequence-17.sql",
+    "postgres_regress/sequence-18.sql",
+    "postgres_regress/sequence-19.sql",
+    "postgres_regress/sequence-20.sql",
+    "postgres_regress/sequence-21.sql",
+    "postgres_regress/sequence-22.sql",
+    "postgres_regress/sequence-23.sql",
+    "postgres_regress/sequence-24.sql",
+    "postgres_regress/sequence-25.sql",
+    "postgres_regress/sequence-26.sql",
+    "postgres_regress/sequence-27.sql",
+    "postgres_regress/sequence-28.sql",
+    "postgres_regress/sequence-29.sql",
+    "postgres_regress/sequence-30.sql",
+    "postgres_regress/sequence-31.sql",
+    "postgres_regress/sequence-32.sql",
+    "postgres_regress/sequence-33.sql",
+    "postgres_regress/sequence-34.sql",
+    "postgres_regress/sequence-35.sql",
+    "postgres_regress/sequence-36.sql",
+    "postgres_regress/sequence-154.sql"
+  ],
+  "postgres_regress/sqljson_jsontable.sql": [
+    "postgres_regress/sqljson_jsontable-2.sql",
+    "postgres_regress/sqljson_jsontable-3.sql",
+    "postgres_regress/sqljson_jsontable-4.sql",
+    "postgres_regress/sqljson_jsontable-5.sql",
+    "postgres_regress/sqljson_jsontable-6.sql",
+    "postgres_regress/sqljson_jsontable-8.sql",
+    "postgres_regress/sqljson_jsontable-9.sql",
+    "postgres_regress/sqljson_jsontable-11.sql",
+    "postgres_regress/sqljson_jsontable-13.sql",
+    "postgres_regress/sqljson_jsontable-14.sql",
+    "postgres_regress/sqljson_jsontable-15.sql",
+    "postgres_regress/sqljson_jsontable-18.sql",
+    "postgres_regress/sqljson_jsontable-19.sql",
+    "postgres_regress/sqljson_jsontable-20.sql",
+    "postgres_regress/sqljson_jsontable-21.sql",
+    "postgres_regress/sqljson_jsontable-22.sql",
+    "postgres_regress/sqljson_jsontable-23.sql",
+    "postgres_regress/sqljson_jsontable-24.sql",
+    "postgres_regress/sqljson_jsontable-25.sql",
+    "postgres_regress/sqljson_jsontable-26.sql",
+    "postgres_regress/sqljson_jsontable-27.sql",
+    "postgres_regress/sqljson_jsontable-28.sql",
+    "postgres_regress/sqljson_jsontable-29.sql",
+    "postgres_regress/sqljson_jsontable-30.sql",
+    "postgres_regress/sqljson_jsontable-31.sql",
+    "postgres_regress/sqljson_jsontable-37.sql",
+    "postgres_regress/sqljson_jsontable-38.sql",
+    "postgres_regress/sqljson_jsontable-45.sql",
+    "postgres_regress/sqljson_jsontable-46.sql",
+    "postgres_regress/sqljson_jsontable-47.sql",
+    "postgres_regress/sqljson_jsontable-48.sql",
+    "postgres_regress/sqljson_jsontable-50.sql",
+    "postgres_regress/sqljson_jsontable-51.sql",
+    "postgres_regress/sqljson_jsontable-52.sql",
+    "postgres_regress/sqljson_jsontable-53.sql",
+    "postgres_regress/sqljson_jsontable-54.sql",
+    "postgres_regress/sqljson_jsontable-55.sql",
+    "postgres_regress/sqljson_jsontable-56.sql",
+    "postgres_regress/sqljson_jsontable-57.sql",
+    "postgres_regress/sqljson_jsontable-58.sql",
+    "postgres_regress/sqljson_jsontable-59.sql",
+    "postgres_regress/sqljson_jsontable-60.sql",
+    "postgres_regress/sqljson_jsontable-61.sql",
+    "postgres_regress/sqljson_jsontable-62.sql",
+    "postgres_regress/sqljson_jsontable-63.sql",
+    "postgres_regress/sqljson_jsontable-64.sql",
+    "postgres_regress/sqljson_jsontable-65.sql",
+    "postgres_regress/sqljson_jsontable-68.sql",
+    "postgres_regress/sqljson_jsontable-69.sql",
+    "postgres_regress/sqljson_jsontable-70.sql",
+    "postgres_regress/sqljson_jsontable-71.sql",
+    "postgres_regress/sqljson_jsontable-72.sql",
+    "postgres_regress/sqljson_jsontable-74.sql",
+    "postgres_regress/sqljson_jsontable-75.sql",
+    "postgres_regress/sqljson_jsontable-76.sql",
+    "postgres_regress/sqljson_jsontable-77.sql",
+    "postgres_regress/sqljson_jsontable-78.sql",
+    "postgres_regress/sqljson_jsontable-79.sql",
+    "postgres_regress/sqljson_jsontable-80.sql",
+    "postgres_regress/sqljson_jsontable-81.sql",
+    "postgres_regress/sqljson_jsontable-82.sql",
+    "postgres_regress/sqljson_jsontable-83.sql",
+    "postgres_regress/sqljson_jsontable-84.sql",
+    "postgres_regress/sqljson_jsontable-86.sql",
+    "postgres_regress/sqljson_jsontable-87.sql",
+    "postgres_regress/sqljson_jsontable-88.sql",
+    "postgres_regress/sqljson_jsontable-89.sql",
+    "postgres_regress/sqljson_jsontable-90.sql",
+    "postgres_regress/sqljson_jsontable-93.sql",
+    "postgres_regress/sqljson_jsontable-94.sql",
+    "postgres_regress/sqljson_jsontable-95.sql",
+    "postgres_regress/sqljson_jsontable-99.sql",
+    "postgres_regress/sqljson_jsontable-100.sql",
+    "postgres_regress/sqljson_jsontable-101.sql",
+    "postgres_regress/sqljson_jsontable-102.sql",
+    "postgres_regress/sqljson_jsontable-103.sql",
+    "postgres_regress/sqljson_jsontable-104.sql",
+    "postgres_regress/sqljson_jsontable-108.sql",
+    "postgres_regress/sqljson_jsontable-109.sql",
+    "postgres_regress/sqljson_jsontable-110.sql",
+    "postgres_regress/sqljson_jsontable-111.sql",
+    "postgres_regress/sqljson_jsontable-112.sql",
+    "postgres_regress/sqljson_jsontable-114.sql",
+    "postgres_regress/sqljson_jsontable-117.sql",
+    "postgres_regress/sqljson_jsontable-119.sql"
+  ],
+  "postgres_regress/sqljson_queryfuncs.sql": [
+    "postgres_regress/sqljson_queryfuncs-1.sql",
+    "postgres_regress/sqljson_queryfuncs-2.sql",
+    "postgres_regress/sqljson_queryfuncs-3.sql",
+    "postgres_regress/sqljson_queryfuncs-4.sql",
+    "postgres_regress/sqljson_queryfuncs-5.sql",
+    "postgres_regress/sqljson_queryfuncs-7.sql",
+    "postgres_regress/sqljson_queryfuncs-8.sql",
+    "postgres_regress/sqljson_queryfuncs-9.sql",
+    "postgres_regress/sqljson_queryfuncs-10.sql",
+    "postgres_regress/sqljson_queryfuncs-11.sql",
+    "postgres_regress/sqljson_queryfuncs-12.sql",
+    "postgres_regress/sqljson_queryfuncs-13.sql",
+    "postgres_regress/sqljson_queryfuncs-14.sql",
+    "postgres_regress/sqljson_queryfuncs-15.sql",
+    "postgres_regress/sqljson_queryfuncs-16.sql",
+    "postgres_regress/sqljson_queryfuncs-17.sql",
+    "postgres_regress/sqljson_queryfuncs-18.sql",
+    "postgres_regress/sqljson_queryfuncs-19.sql",
+    "postgres_regress/sqljson_queryfuncs-20.sql",
+    "postgres_regress/sqljson_queryfuncs-21.sql",
+    "postgres_regress/sqljson_queryfuncs-22.sql",
+    "postgres_regress/sqljson_queryfuncs-23.sql",
+    "postgres_regress/sqljson_queryfuncs-24.sql",
+    "postgres_regress/sqljson_queryfuncs-25.sql",
+    "postgres_regress/sqljson_queryfuncs-26.sql",
+    "postgres_regress/sqljson_queryfuncs-27.sql",
+    "postgres_regress/sqljson_queryfuncs-28.sql",
+    "postgres_regress/sqljson_queryfuncs-29.sql",
+    "postgres_regress/sqljson_queryfuncs-30.sql",
+    "postgres_regress/sqljson_queryfuncs-31.sql",
+    "postgres_regress/sqljson_queryfuncs-32.sql",
+    "postgres_regress/sqljson_queryfuncs-33.sql",
+    "postgres_regress/sqljson_queryfuncs-34.sql",
+    "postgres_regress/sqljson_queryfuncs-35.sql",
+    "postgres_regress/sqljson_queryfuncs-36.sql",
+    "postgres_regress/sqljson_queryfuncs-37.sql",
+    "postgres_regress/sqljson_queryfuncs-38.sql",
+    "postgres_regress/sqljson_queryfuncs-39.sql",
+    "postgres_regress/sqljson_queryfuncs-40.sql",
+    "postgres_regress/sqljson_queryfuncs-41.sql",
+    "postgres_regress/sqljson_queryfuncs-42.sql",
+    "postgres_regress/sqljson_queryfuncs-43.sql",
+    "postgres_regress/sqljson_queryfuncs-44.sql",
+    "postgres_regress/sqljson_queryfuncs-45.sql",
+    "postgres_regress/sqljson_queryfuncs-46.sql",
+    "postgres_regress/sqljson_queryfuncs-47.sql",
+    "postgres_regress/sqljson_queryfuncs-48.sql",
+    "postgres_regress/sqljson_queryfuncs-49.sql",
+    "postgres_regress/sqljson_queryfuncs-50.sql",
+    "postgres_regress/sqljson_queryfuncs-51.sql",
+    "postgres_regress/sqljson_queryfuncs-52.sql",
+    "postgres_regress/sqljson_queryfuncs-53.sql",
+    "postgres_regress/sqljson_queryfuncs-54.sql",
+    "postgres_regress/sqljson_queryfuncs-56.sql",
+    "postgres_regress/sqljson_queryfuncs-57.sql",
+    "postgres_regress/sqljson_queryfuncs-58.sql",
+    "postgres_regress/sqljson_queryfuncs-59.sql",
+    "postgres_regress/sqljson_queryfuncs-60.sql",
+    "postgres_regress/sqljson_queryfuncs-63.sql",
+    "postgres_regress/sqljson_queryfuncs-64.sql",
+    "postgres_regress/sqljson_queryfuncs-65.sql",
+    "postgres_regress/sqljson_queryfuncs-66.sql",
+    "postgres_regress/sqljson_queryfuncs-67.sql",
+    "postgres_regress/sqljson_queryfuncs-68.sql",
+    "postgres_regress/sqljson_queryfuncs-69.sql",
+    "postgres_regress/sqljson_queryfuncs-70.sql",
+    "postgres_regress/sqljson_queryfuncs-71.sql",
+    "postgres_regress/sqljson_queryfuncs-72.sql",
+    "postgres_regress/sqljson_queryfuncs-73.sql",
+    "postgres_regress/sqljson_queryfuncs-74.sql",
+    "postgres_regress/sqljson_queryfuncs-75.sql",
+    "postgres_regress/sqljson_queryfuncs-76.sql",
+    "postgres_regress/sqljson_queryfuncs-77.sql",
+    "postgres_regress/sqljson_queryfuncs-78.sql",
+    "postgres_regress/sqljson_queryfuncs-79.sql",
+    "postgres_regress/sqljson_queryfuncs-80.sql",
+    "postgres_regress/sqljson_queryfuncs-81.sql",
+    "postgres_regress/sqljson_queryfuncs-82.sql",
+    "postgres_regress/sqljson_queryfuncs-83.sql",
+    "postgres_regress/sqljson_queryfuncs-84.sql",
+    "postgres_regress/sqljson_queryfuncs-85.sql",
+    "postgres_regress/sqljson_queryfuncs-86.sql",
+    "postgres_regress/sqljson_queryfuncs-87.sql",
+    "postgres_regress/sqljson_queryfuncs-88.sql",
+    "postgres_regress/sqljson_queryfuncs-89.sql",
+    "postgres_regress/sqljson_queryfuncs-90.sql",
+    "postgres_regress/sqljson_queryfuncs-91.sql",
+    "postgres_regress/sqljson_queryfuncs-92.sql",
+    "postgres_regress/sqljson_queryfuncs-93.sql",
+    "postgres_regress/sqljson_queryfuncs-94.sql",
+    "postgres_regress/sqljson_queryfuncs-95.sql",
+    "postgres_regress/sqljson_queryfuncs-96.sql",
+    "postgres_regress/sqljson_queryfuncs-97.sql",
+    "postgres_regress/sqljson_queryfuncs-98.sql",
+    "postgres_regress/sqljson_queryfuncs-99.sql",
+    "postgres_regress/sqljson_queryfuncs-100.sql",
+    "postgres_regress/sqljson_queryfuncs-101.sql",
+    "postgres_regress/sqljson_queryfuncs-103.sql",
+    "postgres_regress/sqljson_queryfuncs-104.sql",
+    "postgres_regress/sqljson_queryfuncs-105.sql",
+    "postgres_regress/sqljson_queryfuncs-106.sql",
+    "postgres_regress/sqljson_queryfuncs-107.sql",
+    "postgres_regress/sqljson_queryfuncs-108.sql",
+    "postgres_regress/sqljson_queryfuncs-109.sql",
+    "postgres_regress/sqljson_queryfuncs-110.sql",
+    "postgres_regress/sqljson_queryfuncs-111.sql",
+    "postgres_regress/sqljson_queryfuncs-112.sql",
+    "postgres_regress/sqljson_queryfuncs-113.sql",
+    "postgres_regress/sqljson_queryfuncs-114.sql",
+    "postgres_regress/sqljson_queryfuncs-115.sql",
+    "postgres_regress/sqljson_queryfuncs-116.sql",
+    "postgres_regress/sqljson_queryfuncs-117.sql",
+    "postgres_regress/sqljson_queryfuncs-118.sql",
+    "postgres_regress/sqljson_queryfuncs-119.sql",
+    "postgres_regress/sqljson_queryfuncs-120.sql",
+    "postgres_regress/sqljson_queryfuncs-121.sql",
+    "postgres_regress/sqljson_queryfuncs-122.sql",
+    "postgres_regress/sqljson_queryfuncs-123.sql",
+    "postgres_regress/sqljson_queryfuncs-124.sql",
+    "postgres_regress/sqljson_queryfuncs-125.sql",
+    "postgres_regress/sqljson_queryfuncs-126.sql",
+    "postgres_regress/sqljson_queryfuncs-127.sql",
+    "postgres_regress/sqljson_queryfuncs-128.sql",
+    "postgres_regress/sqljson_queryfuncs-129.sql",
+    "postgres_regress/sqljson_queryfuncs-130.sql",
+    "postgres_regress/sqljson_queryfuncs-133.sql",
+    "postgres_regress/sqljson_queryfuncs-134.sql",
+    "postgres_regress/sqljson_queryfuncs-136.sql",
+    "postgres_regress/sqljson_queryfuncs-137.sql",
+    "postgres_regress/sqljson_queryfuncs-138.sql",
+    "postgres_regress/sqljson_queryfuncs-139.sql",
+    "postgres_regress/sqljson_queryfuncs-140.sql",
+    "postgres_regress/sqljson_queryfuncs-141.sql",
+    "postgres_regress/sqljson_queryfuncs-142.sql",
+    "postgres_regress/sqljson_queryfuncs-143.sql",
+    "postgres_regress/sqljson_queryfuncs-144.sql",
+    "postgres_regress/sqljson_queryfuncs-145.sql",
+    "postgres_regress/sqljson_queryfuncs-146.sql",
+    "postgres_regress/sqljson_queryfuncs-147.sql",
+    "postgres_regress/sqljson_queryfuncs-148.sql",
+    "postgres_regress/sqljson_queryfuncs-149.sql",
+    "postgres_regress/sqljson_queryfuncs-150.sql",
+    "postgres_regress/sqljson_queryfuncs-151.sql",
+    "postgres_regress/sqljson_queryfuncs-152.sql",
+    "postgres_regress/sqljson_queryfuncs-153.sql",
+    "postgres_regress/sqljson_queryfuncs-154.sql",
+    "postgres_regress/sqljson_queryfuncs-155.sql",
+    "postgres_regress/sqljson_queryfuncs-156.sql",
+    "postgres_regress/sqljson_queryfuncs-157.sql",
+    "postgres_regress/sqljson_queryfuncs-158.sql",
+    "postgres_regress/sqljson_queryfuncs-159.sql",
+    "postgres_regress/sqljson_queryfuncs-160.sql",
+    "postgres_regress/sqljson_queryfuncs-161.sql",
+    "postgres_regress/sqljson_queryfuncs-162.sql",
+    "postgres_regress/sqljson_queryfuncs-163.sql",
+    "postgres_regress/sqljson_queryfuncs-164.sql",
+    "postgres_regress/sqljson_queryfuncs-165.sql",
+    "postgres_regress/sqljson_queryfuncs-166.sql",
+    "postgres_regress/sqljson_queryfuncs-167.sql",
+    "postgres_regress/sqljson_queryfuncs-168.sql",
+    "postgres_regress/sqljson_queryfuncs-169.sql",
+    "postgres_regress/sqljson_queryfuncs-170.sql",
+    "postgres_regress/sqljson_queryfuncs-171.sql",
+    "postgres_regress/sqljson_queryfuncs-172.sql",
+    "postgres_regress/sqljson_queryfuncs-173.sql",
+    "postgres_regress/sqljson_queryfuncs-174.sql",
+    "postgres_regress/sqljson_queryfuncs-175.sql",
+    "postgres_regress/sqljson_queryfuncs-177.sql",
+    "postgres_regress/sqljson_queryfuncs-178.sql",
+    "postgres_regress/sqljson_queryfuncs-179.sql",
+    "postgres_regress/sqljson_queryfuncs-183.sql",
+    "postgres_regress/sqljson_queryfuncs-184.sql",
+    "postgres_regress/sqljson_queryfuncs-185.sql",
+    "postgres_regress/sqljson_queryfuncs-186.sql",
+    "postgres_regress/sqljson_queryfuncs-187.sql",
+    "postgres_regress/sqljson_queryfuncs-188.sql",
+    "postgres_regress/sqljson_queryfuncs-189.sql",
+    "postgres_regress/sqljson_queryfuncs-190.sql",
+    "postgres_regress/sqljson_queryfuncs-191.sql",
+    "postgres_regress/sqljson_queryfuncs-192.sql",
+    "postgres_regress/sqljson_queryfuncs-193.sql",
+    "postgres_regress/sqljson_queryfuncs-194.sql",
+    "postgres_regress/sqljson_queryfuncs-195.sql",
+    "postgres_regress/sqljson_queryfuncs-196.sql",
+    "postgres_regress/sqljson_queryfuncs-197.sql",
+    "postgres_regress/sqljson_queryfuncs-198.sql",
+    "postgres_regress/sqljson_queryfuncs-199.sql",
+    "postgres_regress/sqljson_queryfuncs-200.sql",
+    "postgres_regress/sqljson_queryfuncs-211.sql",
+    "postgres_regress/sqljson_queryfuncs-212.sql",
+    "postgres_regress/sqljson_queryfuncs-213.sql",
+    "postgres_regress/sqljson_queryfuncs-214.sql",
+    "postgres_regress/sqljson_queryfuncs-215.sql",
+    "postgres_regress/sqljson_queryfuncs-216.sql",
+    "postgres_regress/sqljson_queryfuncs-217.sql",
+    "postgres_regress/sqljson_queryfuncs-218.sql",
+    "postgres_regress/sqljson_queryfuncs-219.sql",
+    "postgres_regress/sqljson_queryfuncs-220.sql",
+    "postgres_regress/sqljson_queryfuncs-221.sql",
+    "postgres_regress/sqljson_queryfuncs-222.sql",
+    "postgres_regress/sqljson_queryfuncs-223.sql",
+    "postgres_regress/sqljson_queryfuncs-224.sql",
+    "postgres_regress/sqljson_queryfuncs-225.sql",
+    "postgres_regress/sqljson_queryfuncs-226.sql",
+    "postgres_regress/sqljson_queryfuncs-227.sql",
+    "postgres_regress/sqljson_queryfuncs-228.sql",
+    "postgres_regress/sqljson_queryfuncs-229.sql",
+    "postgres_regress/sqljson_queryfuncs-230.sql",
+    "postgres_regress/sqljson_queryfuncs-231.sql",
+    "postgres_regress/sqljson_queryfuncs-232.sql",
+    "postgres_regress/sqljson_queryfuncs-233.sql",
+    "postgres_regress/sqljson_queryfuncs-234.sql",
+    "postgres_regress/sqljson_queryfuncs-235.sql",
+    "postgres_regress/sqljson_queryfuncs-236.sql",
+    "postgres_regress/sqljson_queryfuncs-237.sql",
+    "postgres_regress/sqljson_queryfuncs-238.sql",
+    "postgres_regress/sqljson_queryfuncs-239.sql",
+    "postgres_regress/sqljson_queryfuncs-240.sql",
+    "postgres_regress/sqljson_queryfuncs-241.sql",
+    "postgres_regress/sqljson_queryfuncs-242.sql",
+    "postgres_regress/sqljson_queryfuncs-243.sql",
+    "postgres_regress/sqljson_queryfuncs-244.sql",
+    "postgres_regress/sqljson_queryfuncs-245.sql",
+    "postgres_regress/sqljson_queryfuncs-246.sql",
+    "postgres_regress/sqljson_queryfuncs-247.sql",
+    "postgres_regress/sqljson_queryfuncs-248.sql",
+    "postgres_regress/sqljson_queryfuncs-249.sql",
+    "postgres_regress/sqljson_queryfuncs-251.sql",
+    "postgres_regress/sqljson_queryfuncs-252.sql",
+    "postgres_regress/sqljson_queryfuncs-253.sql",
+    "postgres_regress/sqljson_queryfuncs-254.sql",
+    "postgres_regress/sqljson_queryfuncs-258.sql",
+    "postgres_regress/sqljson_queryfuncs-259.sql",
+    "postgres_regress/sqljson_queryfuncs-260.sql",
+    "postgres_regress/sqljson_queryfuncs-261.sql",
+    "postgres_regress/sqljson_queryfuncs-262.sql",
+    "postgres_regress/sqljson_queryfuncs-263.sql",
+    "postgres_regress/sqljson_queryfuncs-264.sql",
+    "postgres_regress/sqljson_queryfuncs-265.sql",
+    "postgres_regress/sqljson_queryfuncs-266.sql",
+    "postgres_regress/sqljson_queryfuncs-269.sql",
+    "postgres_regress/sqljson_queryfuncs-272.sql",
+    "postgres_regress/sqljson_queryfuncs-273.sql",
+    "postgres_regress/sqljson_queryfuncs-274.sql",
+    "postgres_regress/sqljson_queryfuncs-275.sql",
+    "postgres_regress/sqljson_queryfuncs-276.sql",
+    "postgres_regress/sqljson_queryfuncs-277.sql",
+    "postgres_regress/sqljson_queryfuncs-278.sql",
+    "postgres_regress/sqljson_queryfuncs-279.sql",
+    "postgres_regress/sqljson_queryfuncs-280.sql",
+    "postgres_regress/sqljson_queryfuncs-282.sql",
+    "postgres_regress/sqljson_queryfuncs-283.sql",
+    "postgres_regress/sqljson_queryfuncs-284.sql",
+    "postgres_regress/sqljson_queryfuncs-285.sql",
+    "postgres_regress/sqljson_queryfuncs-286.sql",
+    "postgres_regress/sqljson_queryfuncs-287.sql",
+    "postgres_regress/sqljson_queryfuncs-288.sql",
+    "postgres_regress/sqljson_queryfuncs-289.sql",
+    "postgres_regress/sqljson_queryfuncs-290.sql",
+    "postgres_regress/sqljson_queryfuncs-291.sql",
+    "postgres_regress/sqljson_queryfuncs-292.sql",
+    "postgres_regress/sqljson_queryfuncs-295.sql",
+    "postgres_regress/sqljson_queryfuncs-296.sql",
+    "postgres_regress/sqljson_queryfuncs-297.sql",
+    "postgres_regress/sqljson_queryfuncs-298.sql",
+    "postgres_regress/sqljson_queryfuncs-299.sql",
+    "postgres_regress/sqljson_queryfuncs-300.sql",
+    "postgres_regress/sqljson_queryfuncs-301.sql",
+    "postgres_regress/sqljson_queryfuncs-302.sql",
+    "postgres_regress/sqljson_queryfuncs-305.sql",
+    "postgres_regress/sqljson_queryfuncs-306.sql",
+    "postgres_regress/sqljson_queryfuncs-307.sql",
+    "postgres_regress/sqljson_queryfuncs-308.sql",
+    "postgres_regress/sqljson_queryfuncs-309.sql",
+    "postgres_regress/sqljson_queryfuncs-310.sql",
+    "postgres_regress/sqljson_queryfuncs-311.sql"
+  ],
+  "postgres_regress/stats_ext.sql": [
+    "postgres_regress/stats_ext-19.sql",
+    "postgres_regress/stats_ext-39.sql",
+    "postgres_regress/stats_ext-45.sql",
+    "postgres_regress/stats_ext-79.sql"
+  ],
+  "postgres_regress/stats_import.sql": [
+    "postgres_regress/stats_import-121.sql"
+  ],
+  "postgres_regress/stats.sql": [
+    "postgres_regress/stats-371.sql"
+  ],
+  "postgres_regress/subselect.sql": [
+    "postgres_regress/subselect-99.sql",
+    "postgres_regress/subselect-100.sql"
+  ],
+  "postgres_regress/tablespace.sql": [
+    "postgres_regress/tablespace-2.sql",
+    "postgres_regress/tablespace-4.sql",
+    "postgres_regress/tablespace-5.sql",
+    "postgres_regress/tablespace-9.sql",
+    "postgres_regress/tablespace-10.sql",
+    "postgres_regress/tablespace-11.sql",
+    "postgres_regress/tablespace-13.sql",
+    "postgres_regress/tablespace-14.sql",
+    "postgres_regress/tablespace-15.sql",
+    "postgres_regress/tablespace-16.sql",
+    "postgres_regress/tablespace-17.sql",
+    "postgres_regress/tablespace-18.sql",
+    "postgres_regress/tablespace-19.sql",
+    "postgres_regress/tablespace-20.sql",
+    "postgres_regress/tablespace-21.sql",
+    "postgres_regress/tablespace-22.sql",
+    "postgres_regress/tablespace-26.sql",
+    "postgres_regress/tablespace-27.sql",
+    "postgres_regress/tablespace-29.sql",
+    "postgres_regress/tablespace-30.sql",
+    "postgres_regress/tablespace-40.sql",
+    "postgres_regress/tablespace-61.sql",
+    "postgres_regress/tablespace-65.sql",
+    "postgres_regress/tablespace-87.sql",
+    "postgres_regress/tablespace-91.sql",
+    "postgres_regress/tablespace-103.sql",
+    "postgres_regress/tablespace-105.sql",
+    "postgres_regress/tablespace-106.sql",
+    "postgres_regress/tablespace-107.sql",
+    "postgres_regress/tablespace-111.sql",
+    "postgres_regress/tablespace-116.sql",
+    "postgres_regress/tablespace-126.sql",
+    "postgres_regress/tablespace-132.sql",
+    "postgres_regress/tablespace-142.sql",
+    "postgres_regress/tablespace-170.sql",
+    "postgres_regress/tablespace-173.sql",
+    "postgres_regress/tablespace-178.sql",
+    "postgres_regress/tablespace-188.sql",
+    "postgres_regress/tablespace-190.sql",
+    "postgres_regress/tablespace-191.sql",
+    "postgres_regress/tablespace-193.sql",
+    "postgres_regress/tablespace-196.sql"
+  ],
+  "postgres_regress/timestamptz.sql": [
+    "postgres_regress/timestamptz-376.sql",
+    "postgres_regress/timestamptz-377.sql",
+    "postgres_regress/timestamptz-382.sql"
+  ],
+  "postgres_regress/timetz.sql": [
+    "postgres_regress/timetz-53.sql"
+  ],
+  "postgres_regress/transactions.sql": [
+    "postgres_regress/transactions-483.sql",
+    "postgres_regress/transactions-486.sql"
+  ],
+  "postgres_regress/triggers.sql": [
+    "postgres_regress/triggers-79.sql",
+    "postgres_regress/triggers-594.sql",
+    "postgres_regress/triggers-595.sql",
+    "postgres_regress/triggers-976.sql",
+    "postgres_regress/triggers-979.sql",
+    "postgres_regress/triggers-981.sql",
+    "postgres_regress/triggers-984.sql",
+    "postgres_regress/triggers-991.sql"
+  ],
+  "postgres_regress/tsdicts.sql": [
+    "postgres_regress/tsdicts-121.sql",
+    "postgres_regress/tsdicts-125.sql",
+    "postgres_regress/tsdicts-128.sql"
+  ],
+  "postgres_regress/vacuum_parallel.sql": [
+    "postgres_regress/vacuum_parallel-11.sql"
+  ],
+  "postgres_regress/vacuum.sql": [
+    "postgres_regress/vacuum-94.sql",
+    "postgres_regress/vacuum-98.sql",
+    "postgres_regress/vacuum-99.sql",
+    "postgres_regress/vacuum-100.sql",
+    "postgres_regress/vacuum-101.sql",
+    "postgres_regress/vacuum-104.sql",
+    "postgres_regress/vacuum-110.sql",
+    "postgres_regress/vacuum-111.sql",
+    "postgres_regress/vacuum-119.sql",
+    "postgres_regress/vacuum-120.sql",
+    "postgres_regress/vacuum-134.sql",
+    "postgres_regress/vacuum-135.sql",
+    "postgres_regress/vacuum-136.sql",
+    "postgres_regress/vacuum-139.sql",
+    "postgres_regress/vacuum-144.sql",
+    "postgres_regress/vacuum-232.sql",
+    "postgres_regress/vacuum-234.sql",
+    "postgres_regress/vacuum-236.sql",
+    "postgres_regress/vacuum-237.sql",
+    "postgres_regress/vacuum-239.sql",
+    "postgres_regress/vacuum-244.sql",
+    "postgres_regress/vacuum-245.sql",
+    "postgres_regress/vacuum-246.sql",
+    "postgres_regress/vacuum-247.sql",
+    "postgres_regress/vacuum-248.sql",
+    "postgres_regress/vacuum-249.sql",
+    "postgres_regress/vacuum-250.sql",
+    "postgres_regress/vacuum-251.sql"
+  ],
+  "postgres_regress/xml.sql": [
+    "postgres_regress/xml-84.sql",
+    "postgres_regress/xml-85.sql",
+    "postgres_regress/xml-88.sql",
+    "postgres_regress/xml-89.sql",
+    "postgres_regress/xml-90.sql",
+    "postgres_regress/xml-91.sql",
+    "postgres_regress/xml-92.sql",
+    "postgres_regress/xml-93.sql",
+    "postgres_regress/xml-94.sql",
+    "postgres_regress/xml-95.sql",
+    "postgres_regress/xml-96.sql",
+    "postgres_regress/xml-97.sql",
+    "postgres_regress/xml-98.sql",
+    "postgres_regress/xml-99.sql",
+    "postgres_regress/xml-100.sql",
+    "postgres_regress/xml-101.sql",
+    "postgres_regress/xml-102.sql",
+    "postgres_regress/xml-103.sql",
+    "postgres_regress/xml-104.sql",
+    "postgres_regress/xml-105.sql",
+    "postgres_regress/xml-108.sql",
+    "postgres_regress/xml-109.sql",
+    "postgres_regress/xml-143.sql"
+  ]
+}
diff --git a/__fixtures__/regress/known-failures.plpgsql-deparser.json b/__fixtures__/regress/known-failures.plpgsql-deparser.json
new file mode 100644
index 00000000..1c9a0858
--- /dev/null
+++ b/__fixtures__/regress/known-failures.plpgsql-deparser.json
@@ -0,0 +1,74 @@
+[
+  "plpgsql_samples-28.sql",
+  "plpgsql_samples-31.sql",
+  "plpgsql_samples-33.sql",
+  "plpgsql_samples-34.sql",
+  "plpgsql_samples-36.sql",
+  "postgres_regress/case-43.sql",
+  "postgres_regress/case-46.sql",
+  "postgres_regress/case-53.sql",
+  "postgres_regress/case-54.sql",
+  "postgres_regress/copy2-2.sql",
+  "postgres_regress/copy2-3.sql",
+  "postgres_regress/create_index-535.sql",
+  "postgres_regress/create_index-536.sql",
+  "postgres_regress/create_operator-17.sql",
+  "postgres_regress/event_trigger-79.sql",
+  "postgres_regress/explain-46.sql",
+  "postgres_regress/plpgsql-22.sql",
+  "postgres_regress/plpgsql-24.sql",
+  "postgres_regress/plpgsql-28.sql",
+  "postgres_regress/plpgsql-30.sql",
+  "postgres_regress/plpgsql-34.sql",
+  "postgres_regress/plpgsql-38.sql",
+  "postgres_regress/plpgsql-40.sql",
+  "postgres_regress/plpgsql-44.sql",
+  "postgres_regress/plpgsql-46.sql",
+  "postgres_regress/plpgsql-48.sql",
+  "postgres_regress/plpgsql-54.sql",
+  "postgres_regress/plpgsql-60.sql",
+  "postgres_regress/plpgsql-64.sql",
+  "postgres_regress/plpgsql-66.sql",
+  "postgres_regress/plpgsql-68.sql",
+  "postgres_regress/plpgsql-70.sql",
+  "postgres_regress/plpgsql-72.sql",
+  "postgres_regress/plpgsql-74.sql",
+  "postgres_regress/plpgsql-76.sql",
+  "postgres_regress/plpgsql-80.sql",
+  "postgres_regress/plpgsql-81.sql",
+  "postgres_regress/plpgsql-82.sql",
+  "postgres_regress/plpgsql-88.sql",
+  "postgres_regress/plpgsql-89.sql",
+  "postgres_regress/plpgsql-90.sql",
+  "postgres_regress/plpgsql-91.sql",
+  "postgres_regress/plpgsql-92.sql",
+  "postgres_regress/plpgsql-283.sql",
+  "postgres_regress/plpgsql-286.sql",
+  "postgres_regress/plpgsql-289.sql",
+  "postgres_regress/plpgsql-291.sql",
+  "postgres_regress/plpgsql-293.sql",
+  "postgres_regress/plpgsql-295.sql",
+  "postgres_regress/plpgsql-298.sql",
+  "postgres_regress/plpgsql-364.sql",
+  "postgres_regress/plpgsql-365.sql",
+  "postgres_regress/plpgsql-387.sql",
+  "postgres_regress/plpgsql-424.sql",
+  "postgres_regress/plpgsql-504.sql",
+  "postgres_regress/plpgsql-768.sql",
+  "postgres_regress/plpgsql-854.sql",
+  "postgres_regress/plpgsql-857.sql",
+  "postgres_regress/plpgsql-875.sql",
+  "postgres_regress/plpgsql-880.sql",
+  "postgres_regress/privileges-766.sql",
+  "postgres_regress/rangefuncs-128.sql",
+  "postgres_regress/rangefuncs-137.sql",
+  "postgres_regress/rangefuncs-168.sql",
+  "postgres_regress/rowsecurity-23.sql",
+  "postgres_regress/rowsecurity-1068.sql",
+  "postgres_regress/select_views-5.sql",
+  "postgres_regress/stats_ext-741.sql",
+  "postgres_regress/temp-49.sql",
+  "postgres_regress/transactions-239.sql",
+  "postgres_regress/transactions-244.sql",
+  "postgres_regress/triggers-261.sql"
+]
diff --git a/__fixtures__/regress/statements.json.gz b/__fixtures__/regress/statements.json.gz
new file mode 100644
index 00000000..1d972dd3
Binary files /dev/null and b/__fixtures__/regress/statements.json.gz differ
diff --git a/packages/deparser/__tests__/regress/regress-corpus.test.ts b/packages/deparser/__tests__/regress/regress-corpus.test.ts
new file mode 100644
index 00000000..228bd96c
--- /dev/null
+++ b/packages/deparser/__tests__/regress/regress-corpus.test.ts
@@ -0,0 +1,68 @@
+/**
+ * Round-trips the PostgreSQL regression corpus (__fixtures__/regress/statements.json.gz,
+ * built by `npm run fixtures:regress`) through parse -> deparse -> parse, pretty and not.
+ *
+ * known-failures.deparser.json is a ratchet: a new failure fails the test, and so does a listed
+ * statement that now passes. After a deliberate change, refresh it with
+ *   UPDATE_KNOWN_FAILURES=1 npx jest __tests__/regress
+ */
+import * as fs from 'fs';
+import * as path from 'path';
+import * as zlib from 'zlib';
+
+import { TestUtils } from '../../test-utils';
+
+const FIXTURE_DIR = path.join(__dirname, '../../../../__fixtures__/regress');
+const KNOWN_FAILURES_FILE = path.join(FIXTURE_DIR, 'known-failures.deparser.json');
+const UPDATE = process.env.UPDATE_KNOWN_FAILURES === '1';
+
+const { statements } = JSON.parse(
+  zlib.gunzipSync(fs.readFileSync(path.join(FIXTURE_DIR, 'statements.json.gz'))).toString('utf8')
+) as { statements: Record<string, string> };
+const knownFailures: Record<string, string[]> = JSON.parse(fs.readFileSync(KNOWN_FAILURES_FILE, 'utf8'));
+
+const byFile = new Map<string, string[]>();
+for (const key of Object.keys(statements)) {
+  const file = key.replace(/-\d+\.sql$/, '.sql');
+  byFile.set(file, [...(byFile.get(file) ?? []), key]);
+}
+
+const observed: Record<string, string[]> = {};
+const ran = new Set<string>();
+const utils = new TestUtils();
+
+describe('regress corpus round-trip', () => {
+  beforeAll(() => {
+    for (const level of ['error', 'warn', 'log'] as const) jest.spyOn(console, level).mockImplementation(() => {});
+  });
+  afterAll(() => {
+    jest.restoreAllMocks();
+    if (UPDATE) {
+      // Only replace entries for files that ran, so a filtered run (-t, --shard) keeps the rest
+      const merged = { ...knownFailures };
+      for (const file of ran) delete merged[file];
+      Object.assign(merged, observed);
+      for (const file of Object.keys(merged)) if (!byFile.has(file)) delete merged[file];
+      const sorted = Object.fromEntries(Object.entries(merged).sort(([a], [b]) => a.localeCompare(b)));
+      fs.writeFileSync(KNOWN_FAILURES_FILE, JSON.stringify(sorted, null, 2) + '\n');
+    }
+  });
+
+  it('lists only files that are in the corpus', () => {
+    expect(Object.keys(knownFailures).filter((file) => !byFile.has(file))).toEqual([]);
+  });
+
+  it.each([...byFile.keys()])('%s', async (file) => {
+    const failing: string[] = [];
+    for (const key of byFile.get(file)!) {
+      try {
+        await utils.expectAstMatch(key, statements[key]);
+      } catch {
+        failing.push(key);
+      }
+    }
+    ran.add(file);
+    if (failing.length) observed[file] = failing;
+    if (!UPDATE) expect(failing).toEqual(knownFailures[file] ?? []);
+  });
+});
diff --git a/packages/deparser/package.json b/packages/deparser/package.json
index a853bdd7..47b2bcff 100644
--- a/packages/deparser/package.json
+++ b/packages/deparser/package.json
@@ -31,6 +31,7 @@
     "fixtures:sql": "ts-node scripts/make-fixtures-sql.ts",
     "fixtures": "ts-node scripts/make-fixtures.ts",
     "fixtures:upstream-diff": "ts-node scripts/make-upstream-diff.ts",
+    "fixtures:regress": "ts-node scripts/make-regress-fixtures.ts",
     "lint": "eslint . --fix",
     "test": "jest",
     "test:watch": "jest --watch",
diff --git a/packages/deparser/scripts/make-regress-fixtures.ts b/packages/deparser/scripts/make-regress-fixtures.ts
new file mode 100644
index 00000000..2c595bd9
--- /dev/null
+++ b/packages/deparser/scripts/make-regress-fixtures.ts
@@ -0,0 +1,110 @@
+#!/usr/bin/env ts-node
+/**
+ * Builds __fixtures__/regress/statements.json.gz from a libpg_query checkout:
+ * the PostgreSQL regression SQL it vendors (test/sql/postgres_regress, plpgsql_regress)
+ * plus its own test SQL (test/sql/deparse*, test/plpgsql_samples.sql).
+ *
+ *   npm run fixtures:regress -- /path/to/libpg_query
+ *
+ * Check out the libpg_query commit that the pinned libpg-query release was built from
+ * (x-publish.libpgQueryCommit in libpg-query-node versions/18/package.json).
+ */
+import { execFileSync } from 'child_process';
+import * as fs from 'fs';
+import { sync as globSync } from 'glob';
+import { loadModule, parseSync, scanSync } from 'libpg-query';
+import * as path from 'path';
+import * as zlib from 'zlib';
+
+import { generateStatementKey } from './statement-splitter';
+
+const OUT_FILE = path.join(__dirname, '../../../__fixtures__/regress/statements.json.gz');
+const SOURCES = [
+  'test/sql/postgres_regress/*.sql',
+  'test/sql/plpgsql_regress/*.sql',
+  'test/sql/deparse/*.sql',
+  'test/sql/deparse-depesz/**/*.{sql,psql}',
+  'test/plpgsql_samples.sql',
+];
+
+// Split on top-level semicolons using the real scanner, so string/dollar quoting and
+// comments are handled. CREATE RULE (...; ...) and BEGIN ATOMIC ... END bodies stay whole.
+function splitWithScanner(sql: string): string[] {
+  const buf = Buffer.from(sql, 'utf8');
+  const tokens = scanSync(sql).tokens;
+  const out: string[] = [];
+  let start = 0;
+  let parens = 0;
+  let atomic = 0;
+  let cases = 0;
+  let prev = '';
+  for (const tok of tokens) {
+    const word = tok.text.toUpperCase();
+    if (tok.text === '(') parens++;
+    else if (tok.text === ')') parens = Math.max(0, parens - 1);
+    else if (word === 'ATOMIC' && prev === 'BEGIN') atomic++;
+    else if (atomic > 0 && word === 'CASE') cases++;
+    else if (atomic > 0 && word === 'END') {
+      if (cases > 0) cases--;
+      else atomic--;
+    } else if (tok.text === ';' && parens === 0 && atomic === 0) {
+      out.push(buf.subarray(start, tok.start).toString('utf8'));
+      start = tok.end;
+    }
+    if (tok.tokenName !== 'SQL_COMMENT' && tok.tokenName !== 'C_COMMENT') prev = word;
+  }
+  out.push(buf.subarray(start).toString('utf8'));
+  return out;
+}
+
+function splitStatements(sql: string): string[] {
+  let pieces: string[];
+  try {
+    pieces = splitWithScanner(sql);
+  } catch {
+    // e.g. strings.sql has intentionally invalid escapes the scanner rejects
+    pieces = sql.split(/;[ \t]*\r?\n/);
+  }
+  return pieces
+    .map((s) => s.replace(/^(\s*--[^\n]*\n|\s+)+/, '').trim())
+    .filter((s) => s.length > 0);
+}
+
+async function main() {
+  const root = path.resolve(process.argv[2] || process.env.LIBPG_QUERY_DIR || '');
+  if (!fs.existsSync(path.join(root, 'test/sql/postgres_regress'))) {
+    throw new Error('usage: npm run fixtures:regress -- /path/to/libpg_query');
+  }
+  await loadModule();
+  const commit = execFileSync('git', ['-C', root, 'rev-parse', 'HEAD']).toString().trim();
+  const files = SOURCES.flatMap((pattern) => globSync(pattern, { cwd: root })).sort();
+  const seen = new Set<string>();
+  const statements: Record<string, string> = {};
+  let skipped = 0;
+  for (const rel of files) {
+    const relKey = rel.replace(/^test\/(sql\/)?/, '').replace(/\.psql$/, '.sql');
+    splitStatements(fs.readFileSync(path.join(root, rel), 'utf8')).forEach((sql, i) => {
+      if (seen.has(sql)) return;
+      seen.add(sql);
+      try {
+        if (!parseSync(sql).stmts?.length) return;
+      } catch {
+        skipped++;
+        return;
+      }
+      statements[generateStatementKey(relKey, i)] = sql;
+    });
+  }
+  const json = JSON.stringify({ libpgQueryCommit: commit, statements });
+  fs.mkdirSync(path.dirname(OUT_FILE), { recursive: true });
+  fs.writeFileSync(OUT_FILE, zlib.gzipSync(json, { level: 9 }));
+  console.log(
+    `${files.length} files, ${Object.keys(statements).length} statements (${skipped} unparseable skipped) ` +
+      `-> ${path.relative(process.cwd(), OUT_FILE)} (${fs.statSync(OUT_FILE).size} bytes)`
+  );
+}
+
+main().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});
diff --git a/packages/plpgsql-deparser/__tests__/regress-corpus.test.ts b/packages/plpgsql-deparser/__tests__/regress-corpus.test.ts
new file mode 100644
index 00000000..b68d4bf8
--- /dev/null
+++ b/packages/plpgsql-deparser/__tests__/regress-corpus.test.ts
@@ -0,0 +1,63 @@
+/**
+ * Round-trips the PL/pgSQL functions and DO blocks of the PostgreSQL regression corpus
+ * (__fixtures__/regress/statements.json.gz, built by `npm run fixtures:regress` in
+ * packages/deparser) through parse -> deparse -> parse.
+ *
+ * known-failures.plpgsql-deparser.json is a ratchet: a new failure fails the test, and so
+ * does a listed statement that now passes. After a deliberate change, refresh it with
+ *   UPDATE_KNOWN_FAILURES=1 npx jest __tests__/regress-corpus
+ */
+import * as fs from 'fs';
+import { loadModule, parsePlPgSQLSync } from 'libpg-query';
+import * as path from 'path';
+import * as zlib from 'zlib';
+
+import { PLpgSQLTestUtils } from '../test-utils';
+
+const FIXTURE_DIR = path.join(__dirname, '../../../__fixtures__/regress');
+const KNOWN_FAILURES_FILE = path.join(FIXTURE_DIR, 'known-failures.plpgsql-deparser.json');
+const UPDATE = process.env.UPDATE_KNOWN_FAILURES === '1';
+
+const { statements } = JSON.parse(
+  zlib.gunzipSync(fs.readFileSync(path.join(FIXTURE_DIR, 'statements.json.gz'))).toString('utf8')
+) as { statements: Record<string, string> };
+const knownFailures: string[] = JSON.parse(fs.readFileSync(KNOWN_FAILURES_FILE, 'utf8'));
+
+const candidates = Object.keys(statements).filter((key) =>
+  /language\s+'?plpgsql|^\s*do\s/i.test(statements[key])
+);
+
+describe('regress corpus PL/pgSQL round-trip', () => {
+  const utils = new PLpgSQLTestUtils();
+
+  beforeAll(async () => {
+    await loadModule();
+    for (const level of ['error', 'warn', 'log'] as const) jest.spyOn(console, level).mockImplementation(() => {});
+  });
+  afterAll(() => jest.restoreAllMocks());
+
+  it('matches known failures', async () => {
+    const failing: string[] = [];
+    let tested = 0;
+    for (const key of candidates) {
+      try {
+        const parsed = parsePlPgSQLSync(statements[key]) as any;
+        if (!parsed.plpgsql_funcs?.length) continue;
+      } catch {
+        continue;
+      }
+      tested++;
+      try {
+        await utils.expectAstMatch(key, statements[key]);
+      } catch {
+        failing.push(key);
+      }
+    }
+    expect(tested).toBeGreaterThan(500);
+    if (UPDATE) {
+      fs.writeFileSync(KNOWN_FAILURES_FILE, JSON.stringify(failing, null, 2) + '\n');
+    } else {
+      expect(failing).toEqual(knownFailures);
+    }
+  });
+});