Result: done
Files: crates/nikaia-std/src/tools/throws.nika crates/nikaia-std/src/tools/lowered/throws.rs tests/compiler/tests/async_task_crash_is_in_the_throw_set.nika tests/compiler/tests/async_task_crash_is_in_the_throw_set.stdout tests/compiler/tests/async_group_raises_an_unread_failure.nika tests/compiler/tests/async_group_raises_an_unread_failure.stdout
Commit: async: a function that starts an async task throws task::Crashed in its inferred throw set
Body: thrown_in (throws.nika) adds task::Crashed to the direct set of every Expr::Async outside a catch, as std.contracts does for task::scope (Part II 12.7, ADR-async-5 D10), so the generated __NikaiaThrows_… sum gets From<Crashed> + Joined and is a task’s channel. A function with no async task keeps its throw set. async_task_crash_is_in_the_throw_set (an inferred throws with a task that fails, caught by the caller) and async_group_raises_an_unread_failure (a5’s last test, a failure nobody read arrives at the group’s end) both failed on the binary before (a panic in render_refusal, and rustc From<Crashed> not satisfied). Commit 380e720f (before this one) carries a5’s lowering and the fix for defect (b). No Rust function added or changed in this commit.
Part: #988
Tests: async_* –both-settings 32 passed (async_parse_fmt_formats_every_form fails only in a scratch copy, by the relative target/fast/nikaia path); tests/compiler –both-settings 645 passed, 7 failed only on “no such file or directory: target/fast/nikaia” (the scratch copy); it task overlap spawn scope async 74 passed; nikaia-std –lib task 14 passed; clippy clean; both defect tests failed on the binary before; no task::scope/spawn/overlap output changed
Gate: green
Deviation: defect (b) was in the lowering (emit_stmt_expr), not the parser, and went into commit 380e720f with a5’s lowering; the order is reversed (a5 first, then fix 1) because fix 1’s tests need a5’s lowering
Found: crates/nikaia/src/emit/host.rs renders EmitRefused.at as at as usize, so a refusal with at = -1 panics in Span::new (PosOverflow); a5’s async refusals now pass null; probe: any emit refusal built with at: -1
Needs: none
Changelog: Async tasks throw task::Crashed: a function that starts async tasks has task::Crashed in its inferred throw set, and async e, its binding and async { … } run on the group runtime, joined where the checker waits
Owner: none
Disk freed: 0 (test cache 3.3G, 8.2G free, no new entry over 100 MB)
Rs2nika: none
Attribution:
Co-Authored-By: Claude Opus 5.5 noreply@anthropic.com
Claude-Session: https://claude.ai/code/session_01GFeMqxRbtUMiGVyDMxsvEq
Pushed: local 6500f9e030b29ecaba30f304af01ea93cec08c53
