agent: builder model: opus max_turns: 80 budget_usd: 16 —
get ... ?? return over a list of literals, compared, reaches rustc (&&str vs &str, &{integer} vs {integer})Score: compiler bug, false acceptance (nikaia check passes, rustc refuses), on a common form; the copy fact exists and is too narrow. Held back for #938, which is closed.
Facts: Where things live, Traps already met, Commands
fn has_a(k: i64) -> bool {
let xs = ["a", "b"]
return (xs.get(k) ?? return false) == "a"
}
fn main() { println(f"{has_a(0)} {has_a(5)}") }Rows:
&str with str. Must print true false.fn first_is_a(xs: Vec[String], k: i64) -> bool { return (xs.get(k) ?? return false) == "a" } called with ["a", "b"] - the same rustc error. Must print true.let xs = [1, 2] / let x = xs.get(k) ?? return false / return x == 1 - rustc Can’t compare &{integer} with {integer}. Must print true false.let xs = ["a", "b"]; let x = xs.get(k) ?? return false; return x == "a" (the architect saw it fail at c30b7bc0; re-probe). Must print true false.true false, must stay): row c with let xs: Vec[i64] = [1, 2].An unfixed binary for before/after probes: /home/user/nikaia-suite/target/fast/nikaia.
The copy is the copied_jump_reads fact, read by the emitter at crates/nikaia-std/src/tools/emit_core_flow.nika:774 (writes nikaia_std::num::value(__nikaia_value) in the Some arm). It is set in two places:
check_core_ops.nika:791 (a ?? anywhere): check_core_ops_a_word(inner);check_core_stmt.nika:1061-1064 (under a let): a_copy_by_value(bound), then check_core_stmt_copied_jump_reads (:128).
Both cover a declared number element (row e), not an untyped number literal list (row c; its element type is probably still the literal’s open type when the test runs) nor a list of text views (rows a, b, d; a &str element copies, so the Some arm can deref it, but num::value is for numbers: check what it accepts in crates/nikaia-std/src/num* and use a deref rustc takes for &&str, e.g. *__nikaia_value or .copied(), any lowering rustc accepts). Widen the two tests, and the emitter if num::value does not fit text, without making a non-copy element (a Vec[String] of owned text, a struct) copy: Nikaia never copies behind your back.Tests:.tests/compiler/tests/get_or_return_compared_over_literals.nika + .stdout (rows a-e, one function each, printing their answers). Commit emit: a get past a jump over a list of literals is the element, compared by value (Fixes #947).The new test fails on the unfixed compiler and passes through nikaia test --project tests/compiler --both-settings (by name), with the tests whose names contain coalesce, jump, get_or or copied (run by name); lower-std fixpoint clean (a change in a lowered tools/*.nika other than the files you edited is a finding: name it under Tests:); build, fmt, clippy, pre-push-check.sh; committed locally. Changelog: one line. Stop about 15 turns before max_turns, commit what is finished and report partial.
An edit is needed outside check_core_ops.nika, check_core_stmt.nika, emit_core_flow.nika, crates/nikaia-std/src/num* (std’s value), their lowered twins and the test; an error in another agent’s file.
Not yours, never stage: every file git status shows modified or untracked at your start, and every docs/briefs/* file except your report.
docs/builder-facts.md first. develop in the main checkout; git status at start: other agents’ uncommitted files are not yours, never touch or stage them.git add <files> only (scripts/commit.nika -- REPORT does it); commit locally after each step and never push: the driver runs the complete suite and pushes (.claude/agents/builder.md, Cheap checks only; owner, 2026-10-31).cargo build --profile fast -p nikaia, lower-std and its fixpoint when a tools/*.nika changed, cargo fmt, cargo clippy --all-targets -- -D warnings, scripts/pre-push-check.sh, the tests the brief names and the ones your change touches. No gate.nika.CHANGELOG.md, badges; no new NK code. New tests in Nikaia only; never the full suite. No foreground sleep, no polling; scripts in files.std or the toolchain lacks stops the work: no code around it unless an ADR or Part I-III refuses it (name it). Else Result: blocked, Found: gap + probe, Needs: architect decision (CLAUDE.md, A missing form stops the work).NIKAIA_CACHE_LIMIT=2G; at most two clones with target/ in the machine; delete your own clone’s target/ and target/release/nikaia-scratch at the end; report GB freed.Result: partial with what you ruled out, the probe, and the suspected file and function (.claude/agents/builder.md).target/fast/nikaia run scripts/commit.nika -- REPORT, which writes Pushed: local <sha> into it. A report without a Pushed: line, or with a placeholder left in (TC, DISK), is not done and cuts the batch (k3a1 2026-10-29: Result: done, nothing committed)./home/user/Nikaia/docs/briefs/bugs/b14-947-get-or-return-compared.md.report.md)Fields of docs/architect.md, Briefs and reports: Result: done|noop|partial|blocked (the bare word alone on that line: Result: done, never a summary after it, which cuts the batch, b869a 2026-10-27; Owner: is a question for the owner or none, never a role), Files, Commit, Body (optional, one paragraph for the commit message), Fixes, Pushed, Tests, Gate (green|red), Deviation, Found, Needs, Changelog, Owner, Disk freed, and for a move Rs2nika: (the kept N of M lines of rs2nika --score, then the three costliest hand edits; none for a task that moves no Rust, none (redesign) for a brief with Shape: redesign and no Convert: line). none where nothing, and then the bare word: Deviation: none (a note) cuts the batch (batch.nika compares exactly); a note goes into the commit message. Found: is only for a defect outside your change (it cuts the batch); a process event such as another session resetting or rewriting your files is no Found:, it goes under Needs: (m3a 2026-10-28); a converter draft that came out wrong is no Found:, it is one of the costliest edits under Rs2nika:, which the converter lane reads (e12-4b 2026-10-27); how you solved your own step goes into the commit message. Deviation: is only a step of the brief built otherwise than written or not built (a choice the brief left to you, such as keep what X needs and say so, is no deviation: it goes into the commit message; nor is building two steps in one commit when every step is built, e12-3a 2026-10-27, nor a step another commit on develop already built, shown by your test failing with that commit’s change reverted, b889 2026-10-27: name the commit in Body:, nor a test’s expected .stdout/.stderr taken from what the program really prints where the brief’s sketch of it was short or wrong, b934 2026-10-29: say so in Body:, nor a lowering that follows the ADR governing it where the brief’s expected lowering contradicts that ADR, b933 2026-10-29: name the ADR in Body:, nor a lowering other than the brief’s where rustc cannot take the brief’s, b1029 2026-10-31: say why in Body:, nor re-keying an allow-list entry (KNOWN) whose hash changed for the same program and the same reason, b-fixforward-sweep2 2026-10-28: say so in Body:, nor an existing test’s expected .stdout/.stderr updated because your change rightly changes the message it prints, b1012b 2026-10-31: name the test in Body:); how you verified (e.g. a test not run against the unfixed compiler) goes under Tests:. A noop says why under Tests: (what was probed), not under Deviation:. Final answer, one line: done <sha>, report <path> (or BLOCKED: ... / PUSH REJECTED ...).
Attribution: Co-Authored-By: Claude Opus 5.5 noreply@anthropic.com Claude-Session: https://claude.ai/code/session_01GFeMqxRbtUMiGVyDMxsvEq