Three parked candidates accumulated while the Standard-tier solver track closed
and the notation-quality pass landed, which is the threshold at which the house
rule opens a batch pass. PASS13_CANDIDATES.md reopens as Batch 2 with P13-I1
(this), P13-I2 (Staff::default_clef never consulted), P13-I3 (the notehead stem
anchors).
P13-I1 was filed as "two elided fields". Checking before writing turned up a
third, and it is the one that matters: `diagnostics: Vec<LayoutDiagnostic>`
appears NOWHERE in core_spec, though it is how the projection's honesty rule
manifests. So Chapter 7's listing gains break_origins, diagnostics, and catalog;
BreakOrigin and LayoutDiagnostic gain their shapes.
And it gains req:layoutir:coverage-diagnostics, ratified as implemented: an
object the projection cannot engrave faithfully -- a pitch with no resolved
spelling, a glyph the bound catalog does not carry -- MUST be recorded as a
LayoutDiagnostic AND still placed, as a fallback notehead or a zero-extent traced
anchor. It MUST NOT silently substitute a plausible shape, and MUST NOT drop the
object. Both halves matter: dropping it breaks the round-trip surjection, so a
hit-test can no longer find what the author wrote; guessing produces a score that
looks engraved and is wrong, with nothing in the IR to say so.
Locked by an_unengravable_object_is_recorded_and_still_placed, which drives a
percussion clef (no bundled glyph) and asserts all three halves: the diagnostic
names the object, no glyph stands in for it, and a zero-extent anchor keeps its
provenance addressable.
Spec rebuilds clean, no undefined references, new label registered. No code
change beyond the test; zero golden churn.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Levi Neuwirth
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