Lyric

What changed in v4.3.3 — 2026-09-04

Round 6 of the sweep, aimed at what round 5 built. Two findings in it, both mine, and one older one found while checking that round 5 had broken nothing.

Fixed

• Disposing a VM now frees a guest parked on Wait.Interrupt. It did not, and the reason it looked like it did is the point: a guest waiting on a SOCKET is woken because Dispose closes the socket under its select. A guest parked on the interrupt holds no descriptor, so nothing woke it — the host's thread was gone for good while Dispose returned in a millisecond and reported success. "Disposing frees a parked guest" was true by accident, for the parks that happened to hold a handle.

  A disposed VM now answers that wait the way an interrupt does: every parked task wakes, the run drains, and the call returns. Wait.Interrupt is the language's "you are being asked to stop", which makes it the honest answer for a VM that is ending — and it is the documented shutdown shape, so it was the case the contract exists for that did not work.

• A disposed VM no longer leaves Ctrl+C swallowed for the whole process. The interrupt listening count moves on transitions, and the poll that moves it read and updated it outside the lock Dispose uses to read the same flag. A raise landing between the two adds a listener that nothing ever subtracts, and while that count is above zero the Ctrl+C handler cancels the signal — on behalf of a VM that no longer exists. The transition is one step now, and a disposed VM does not arm at all.

• A variant pattern over an OPTIONAL enum stops calling it a non-enum. match (e) { null => …, E.A => … } on a ?E is refused by the lowering, which is unchanged — but it said "a match over a non-enum", sending the reader to look for a mistake in the type rather than at the missing lowering. It now names the optional and says what to do: narrow it first, then match the value. Matching an optional with a binding arm is unaffected.

The full changelog →