Coverage backfill for an already-shipped capability — NO language /
checker / codegen / schema / runtime change (4 new files, all under
examples/ and crates/ail/tests/).
Property protected: the M3 export gate is_c_abi_type runs as a
per-parameter loop, accepting a single-ctor all-scalar record
independently per param; the staticlib forwarder maps every
non-scalar Type::Con to a bare ptr (M3-frozen). So a kernel
(State, Tick) -> State with BOTH params single-ctor all-scalar
records is callable from C today — a record Tick pushed per call,
not just a scalar sample. Every shipped M3 fixture pushes a scalar
Float; none pinned the two-record-param shape (the actual minimal
data-server binding). This is the residual of the retired M4.
Added:
- examples/embed_backtest_step_tick.ail (own Tick)
- examples/embed_backtest_step_tick_borrow.ail (borrow Tick)
- crates/ail/tests/embed/tick_roundtrip.c (C host, -DBORROW)
- crates/ail/tests/embed_tick_e2e.rs (2 E2E tests)
Both E2E tests pass on HEAD (Boss-verified, not just agent-claimed):
own + borrow, globally leak-free (Sigma allocs == Sigma frees across
the ctx readback + g_rc atexit lines, the M3 dual-stat-line model),
acc/n value-correct, exit 0. Independently re-confirms the M4
retirement reasoning: the capability is genuinely present in M3.
Honest, deliberately NOT silenced: the new fixtures emit an
advisory [over-strict-mode] warning (ail check still exits 0,
non-gating) that the M3 scalar-sample original does not. Root cause
characterized: a conservative over-strict-mode false-positive whose
discriminator is the nested second (match tick ...) — structurally
identical `st` handling warns when its term-ctor rebuild is nested
inside an inner match. It is advisory only and does not affect
codegen, the ABI, or the proven property. The fixture is kept in
its LLM-natural form (dont-adapt-tests-to-bugs); the lint precision
wart is surfaced as a separate finding, not papered over.
