Row 3 (root K): emitter-attested use-line for anonymous record-literal heads — materialization_carriers 51 → 49

[briansrls]

Summary

Vertical-integrator lane (swift-moth-294, node adhoc-497a24aa-140): first Row-3 packet on the materialization_carriers error board.

Mechanism. reference_derived_use_lines synthesizes a use-line only for candidates the module's authored source text attests. An anonymous record literal (retention: { release_policy: …, capacity: … } in extdeps.realization.compile_stage_memo / parse_table_memo) gets its head from the emitter (ProviderRetention { .. }), a name the authored source structurally cannot spell — so the gate refused exactly the candidate the emitted bytes need, and rustc reported E0422 on a head the emitter itself wrote.

Fix. Third attestation arm collect_anonymous_record_lit_heads (src/v1/05_emit_rust.dag): admits a candidate only when it is a head the emitter will render for an anonymous record literal in this module's items, computed by the proposer's own tn-Absent decision chain (emit_inferred_type_leaf_name when the summary is known, else anonymous_record_lit_surface_name). This is not a widened text gate: the deep inferred/type-summary over-collection route (the AuthoredTokenOrdinal fabrication receipt) stays refused, and the registry-resolve, transitive export-proof, kernel, local-decl and already-imported walls are unchanged. Gate note corrected in place.

Stage0 splice, exact hunks only. v1_compiler_emit_rust.rs is regenerated for exactly this change. A fresh whole-src/v1 emit also restores three other lanes' content the committed seed is missing (#8466's trait_bound_witness wiring, #8460's callable-wrap, the function-value lowering #8516 restores) — deliberately not carried here (ratified by smart-ram-730): three lanes of unrelated restored content would make this span delta unattributable. That drift is routed to its owners.

Measurement — one instrument, one base, composition grain

Instrument identical to #8460/#8490 (gunbc compile → cssl_assemble → cargo build --release --lib, CSSL_STD_SEED_LINK=1), executed remotely with binaries built beside the measurement, both arms at main b2dd729f92:

BEFORE: E0308 20 · E0277 16 · E0599 3 · E0425 3 · E0422 2 · E0369 2 · E0282 2 · E0061 2 · E0560 1 = 51
AFTER:  E0308 20 · E0277 16 · E0599 3 · E0425 3 ·           E0369 2 · E0282 2 · E0061 2 · E0560 1 = 49

E0422 → 0 (both sites now import through pub use crate::std_cache_interface::{ProviderRetention};); no other row moved. Note: this base's composition differs from #8490's receipt at dd9c2307 (two different 51s exist; flagged to the coordinating session) — full receipt in docs/probes/materialization_carriers_row3_use_line_2026-08-19.md.

Declared residue (not silently absorbed): Row 3's three E0425 NonEmptyStr sites did not move. A companion signature-leaf attestation arm was built, measured at zero effect, and removed before this PR — the signature's top-level leaf is the already-imported CacheInterfaceId; the NonEmptyStr spelling comes from a deeper alias-peel inside render_rust_fn_sig_type. That trio is the next packet, root-caused at the renderer.

Test plan

• Witness dag/test/claim/anonymous_record_head_use_line_witness_test.dag: fixture references ProviderRetention only through an anonymous argument-position literal; asserts the synthesized use-line + emitted head, with a negative over-collection assertion. Executed green through the real pipeline on the fixed tree (w_anonymous_record_head_gets_use_line → true); red direction evidenced by the pre-fix baseline bytes (use-line absent at the same construction).
• Whole-src/v1 regen route verified: the spliced file matches the fresh emit of the edited authority at exactly these hunks (offsets shift −5 from drift hunks not carried).
• Remote cargo build of the assembled probe crate before/after, exit/histogram as above.

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