-- Builtin names like flat, frq, map, flt, cat, len, ord are reserved and
-- cannot be reused as local binding names. Binding `flat=cat ws " "` and
-- then writing `spl flat ". "` would silently dispatch the `flat` operand
-- to the 1-arg flatten builtin (not the local binding), surfacing as a
-- misleading ILO-T006 arity mismatch on `flat`.
--
-- The parser now rejects builtin-named binding LHS with a friendly
-- ILO-P011 + rename hint, mirroring the existing user-function-name
-- precedent. So the agent's first retry is the right one.
--
-- Correct shape: pick a non-builtin name (here `body` for a joined string).
main>n
ws=["one" "two" "three"]
body=cat ws " "
parts=spl body " "
len parts
-- run: main
-- out: 3