agent: builder model: opus max_turns: 90 budget_usd: 18 —
match/if with a null end and a text-literal end is refused NK1104 when the same parameter also takes an owned textBlocks: none (found by b20, docs/briefs/bugs/b20-1088-tuple-option-part-in-arms.md.report.md)
Score: compiler bug, a wrong refusal of a program Part I allows (ADR-364: the wanted type reaches every end). Cause suspected, not traced to the line: medium size.
Facts: Where things live, Traps already met, Commands
target/fast/nikaia at aa1ca981)fn other(t: String) -> (i32, String?) { return (2, t.clone()) }
fn literal(x: i32) -> (i32, String?) { return match x { 0 => (1, null), else => (2, "lit") } }
fn show(r: (i32, String?)) {
let (a, b) = r
println(f"{a} {b ?? "none"}")
}
fn main() {
show(literal(1))
show(other("t"))
}Expected 2 lit / 2 t. Got NK1104 “You’re returning (?, ref String), but the function is declared to return (i32, String?)” at the match.
literal’s body (with other and show as above) |
result |
|---|---|
return match x { 0 => (1, null), else => (2, "lit") } |
NK1104 (?, ref String) |
return if x == 0 { (1, null) } else { (2, "lit") } |
NK1104 (?, ref String) |
let n: i32 = 1 then return match x { 0 => (n, null), else => (n, "lit") } |
NK1104 (i32, ref String) |
return match x { 0 => (1, "a"), else => (2, "lit") } |
passes |
two return statements, (1, null) and (2, "lit") |
passes |
row 1 without show(other("t")) |
passes |
crates/nikaia-std/src/tools/check_core_leaves.nika, the return check (lines 685-729): found becomes a view at if lending (686) or through lent_arms_handed_back (693); then check_core_literal_by_use (413) reaches check_texts.nika tuple_literal, whose ends branch (404-425) gives every end the joined found (plain) rather than the end’s own type. b20 (54503278) fixed the same shape in check_overflow.nika check_overflow_ends_into_nullables by reading each end’s type from state.arm_types. What the owned caller switches on is a text-tier fact (text_tiers.nika): dump the facts for row 1 with and without show(other("t")) and compare, before editing.
Tests:).check_overflow_tuple_into_nullables, check_overflow_ends_into_nullables, tuple_literal), keep them agreeing and name them in Body:.lower-std and its fixpoint.tests/compiler/tests/tuple_null_end_owned_caller.nika + .stdout: rows 1-3, each through one show parameter beside an owned result as in the probe; fails on the unfixed binary. Also run tuple_option_part_in_arms and the tests named tuple|nullable|tier.
Commit check: a tuple with a null end and a text-literal end fits a parameter that also takes owned text (Fixes #1101).The new test fails on the unfixed compiler and passes through nikaia test --project tests/compiler --both-settings. Also: lower-std fixpoint clean; 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 crates/nikaia-std/src/tools/check_*.nika, text_tiers.nika, tiers.nika, their lowered twins, lowered.rs and the new test. Or you hit 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/b24-1101-tuple-null-end-owned-caller.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 or red <check>: your cheap checks, never none, which cuts the batch, j4 2026-10-31), 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