The standard-first ALTER COLUMN constraint gap-fill advanced mode lacked:
- ALTER COLUMN <c> SET DATA TYPE <ty> — ISO canonical synonym for the
PostgreSQL TYPE shorthand (same AlterColumnType action + executor).
- SET NOT NULL / DROP NOT NULL — reuse the ADR-0029 do_add_constraint /
do_drop_constraint executors (dry-run + internal-table guards free).
- SET DEFAULT <expr> / DROP DEFAULT — SET DEFAULT uses a dedicated
raw-SQL executor (do_set_column_default); sql_expr yields no typed
Value, so it can't go through do_add_constraint. DROP DEFAULT reuses
do_drop_constraint.
Grammar: AT_ALTER_COLUMN gains a tail Choice (type / set / drop), reusing
SQL_TYPE and the CREATE TABLE DEFAULT_NODES; builder dispatch routes the
new column-attribute forms; runtime decomposes to the executors.
ADR-0035 Am2 corrected in-place: SET DEFAULT decomposes to
do_set_column_default, not do_add_constraint (Value-based) — found during
build.
Tests (test-first): 6 parse + 7 Tier-3 execution via run_replay. Suite
1962/0/1; clippy clean.
claude@clouddev1
338dc8a4cf