Lyric

What changed in v2.13.0 — 2026-08-22

The first link of the train that runs ahead of v3.0.0: everything that does not need a major ships first, on its own, and deprecates what it replaces. This is the mechanism those deprecations will be written with.

Added

• A deprecation may name the version that removes it. @Deprecated carries a second field:

  @Deprecated { message = "use renew", until = "3.5" }
  pub fn old(): int { return 1; }
  

  Building with a toolchain that has reached that version is an error (LYR-SEM0081), as is a version the compiler cannot read. A deprecation makes two promises — use something else, and this will disappear — and only the first was ever written where anyone could see it; the second lived in a release note, which is another way of saying it lived in somebody's memory.

  Three decisions in it, each of which could have gone the other way:

  • The named version is the one that removes it. until = "3.5" fails AT 3.5, not one release later, so the failure lands on whoever is preparing that release.
  • The check sits at the declaration, not at a use. A form kept past its date is wrong whether or not anything still calls it, and dead code would never trip a use-site warning.
  • It stops the build rather than warning. A warning about a removal that should already have happened is a warning nobody acts on — the same reasoning as the documentation ratchet and the corpus-silence invariant.

  Not a second attribute: an @Sunset beside @Deprecated would be a second mechanism for "this is going away", and the two would eventually disagree about a declaration carrying one and not the other. An empty until is the ordinary policy — warn now, remove at the next major.

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