fix(rust): box an optional of the struct itself (+3)

[gHashTag]

Closes #3375

A struct holding an OPTIONAL of itself is infinitely sized in Rust:

pub left: Option<KDNode>             error[E0072]
pub children: [Option<OctNode>; 8]   the same, once per element

Zig writes ?KDNode and stores it inline, because its optional of a struct is a tagged union of known size. Rust needs the indirection spelled out, and rustc says so and names the repair.

Only Option<ThisStruct> is rewritten, and only on an exact name match. Vec<ThisStruct> is already indirect and is left alone; a bare ThisStruct would still be infinite but does not occur in the corpus, and guessing at a shape nothing exhibits is how a rule outgrows its evidence.

Measured: 357 → 360, zero regressions — kd_tree, octree, quadtree.

Worth naming: octree.t27 was recorded as a regression in #3247, where I wrote that [8]?OctNode is "genuinely infinitely sized". That was true of the emitted Rust and not of the spec. It is no longer a regression, and the note that claimed it is now wrong.

Boundary control, four cases in one probe:

written	emitted
?Node inside Node	Option<Box<Node>>
?Other	Option<Other> — untouched
?NodeExtra	Option<NodeExtra> — an exact match does not catch a prefix
[]Node	Vec<Node> — untouched

[github-actions]

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[github-actions]

PR Dashboard

Generated at: 2026-09-06 07:48:16 UTC

• fix(rust): box an optional of the struct itself (+3) #3376 fix(rust): box an optional of the struct itself (+3) | Created: 2026-09-06 | Updated: 2026-09-06 | 17 failing / 31 total
• fix(tri): record two refusals where the tool looks #3372 fix(tri): record two refusals where the tool looks | Created: 2026-09-06 | Updated: 2026-09-06 | 5 failing / 35 total
• fix(rust): a function type is a type alias, not a const's value #3365 fix(rust): a function type is a type alias, not a const's value | Created: 2026-09-06 | Updated: 2026-09-06 | 0 failing / 38 total
• coq(CorePhi): replace proofs that were never checked by a compiler #3343 coq(CorePhi): replace proofs that were never checked by a compiler | Created: 2026-09-06 | Updated: 2026-09-06 | 5 failing / 32 total
• ci(coq): report all thirteen files instead of stopping at the first error #3342 ci(coq): report all thirteen files instead of stopping at the first error | Created: 2026-09-06 | Updated: 2026-09-06 | 3 failing / 30 total
• skill: spool four lessons from this pass #3327 skill: spool four lessons from this pass | Created: 2026-09-05 | Updated: 2026-09-05 | 1 failing / 28 total
• chore(ci)(deps): bump actions/attest-build-provenance from 1 to 4 #3001 chore(ci)(deps): bump actions/attest-build-provenance from 1 to 4 | Created: 2026-09-01 | Updated: 2026-09-06 | 0 failing / 30 total
• chore(ci)(deps): bump softprops/action-gh-release from 2 to 3 #3000 chore(ci)(deps): bump softprops/action-gh-release from 2 to 3 | Created: 2026-09-01 | Updated: 2026-09-06 | 0 failing / 28 total
• chore(ci)(deps): bump github/codeql-action from 3 to 4 #2999 chore(ci)(deps): bump github/codeql-action from 3 to 4 | Created: 2026-09-01 | Updated: 2026-09-06 | 0 failing / 28 total
• Land the formal verification harness on master (it has never run) #2727 Land the formal verification harness on master (it has never run) | Created: 2026-08-27 | Updated: 2026-09-05 | 5 failing / 24 total
• chore(deps)(deps): bump thiserror from 2.0.18 to 2.0.20 #2693 chore(deps)(deps): bump thiserror from 2.0.18 to 2.0.20 | Created: 2026-08-24 | Updated: 2026-08-28 | 3 failing / 34 total
• chore(deps)(deps): bump hyper from 1.10.1 to 1.11.0 #2692 chore(deps)(deps): bump hyper from 1.10.1 to 1.11.0 | Created: 2026-08-24 | Updated: 2026-08-28 | 3 failing / 33 total
• chore(deps)(deps): bump base64 from 0.22.1 to 0.23.1 #2691 chore(deps)(deps): bump base64 from 0.22.1 to 0.23.1 | Created: 2026-08-24 | Updated: 2026-08-28 | 3 failing / 34 total
• chore(deps)(deps): bump serde from 1.0.228 to 1.0.229 #2690 chore(deps)(deps): bump serde from 1.0.228 to 1.0.229 | Created: 2026-08-24 | Updated: 2026-08-28 | 3 failing / 34 total
• chore(deps)(deps): bump uuid from 1.23.2 to 1.25.0 #2689 chore(deps)(deps): bump uuid from 1.23.2 to 1.25.0 | Created: 2026-08-24 | Updated: 2026-08-28 | 3 failing / 34 total
• Unbreak FPGA CI and correct two unbacked hardware claims #2081 Unbreak FPGA CI and correct two unbacked hardware claims | Created: 2026-08-11 | Updated: 2026-08-20 | 5 failing / 27 total

Summary

Status	Count
Total Open PRs	16
PRs with Failing Checks	10
PRs with All Checks Green	6
READY	4
FAILING	10
PENDING	0
NO CHECKS YET	0

These columns do not partition: 4 + 10 + 0 + 0 = 14, and there are 16 open PRs. A PR is being counted twice or not at all.

Seal Status

• ⚠️ STALE -- sha256(compiler.rs)=b1f4644c92c7 != manifest seal=87e5cbd3ad94.
  The committed NMSE numbers were certified against an older compiler.rs.
  Run scripts/reseal-check.sh locally for the two-step reseal command (advisory; not a merge gate).