Result: done
Files: crates/nikaia-std/src/arm.rs crates/nikaia-std/src/lib.rs crates/nikaia-std/src/tools/check_arguments.nika crates/nikaia-std/src/tools/check_arm_leaves.nika crates/nikaia-std/src/tools/check_facts.nika crates/nikaia-std/src/tools/check_references.nika crates/nikaia-std/src/tools/emit_core_args.nika crates/nikaia-std/src/tools/emit_expr.nika crates/nikaia-std/src/tools/lowered/check_arguments.rs crates/nikaia-std/src/tools/lowered/check_arm_leaves.rs crates/nikaia-std/src/tools/lowered/check_facts.rs crates/nikaia-std/src/tools/lowered/check_references.rs crates/nikaia-std/src/tools/lowered/emit_core_args.rs crates/nikaia-std/src/tools/lowered/emit_expr.rs tests/compiler/tests/a_lent_argument_from_arms_view_and_new.nika tests/compiler/tests/a_lent_argument_from_arms_view_and_new.stdout
Commit: emit: an if/match lent whole with view arms and arms that make a value (#894)
Body: A lent argument (declared ref or inferred lent) whose arms are a lent name and values made in the arm is put into one value made at the argument and lent through the call: look(&*if c { nikaia_std::arm::Arm::View(t) } else { nikaia_std::arm::Arm::Own(P { .. }) }), text through EitherText arm by arm (either(..), the #562 leaves). The Arm is a temporary of the argument, so it outlives the call in edition 2024, which &P { .. } in an arm’s tail does not; it needs no Clone, unlike Cow. New nikaia_std::arm (enum Arm<'a, B: ?Sized, O>, Deref to B via O: Borrow<B>), facts lent_arms / lent_arm_leaves, decided in check_arguments before ADR-282 D11 (lent_arms_view_and_new in check_arm_leaves). Only where an arm is a lent name; an arm that is null, a place of its own, or a non-name view leaves the argument to the rules before (keeps emit_pattern’s if raw_any { "byte" } else { called.clone() } as it was). a_name_that_is_lent became pub.
Fixes: #894
Pushed: b82ab265225472e0b0353472dde7beed2fd7524b
Tests: new a_lent_argument_from_arms_view_and_new (if/match, declared ref and inferred lent, struct and String) failed on the unfixed compiler (rustc mismatched types at 4 sites); nikaia test –both-settings –project tests/compiler 186 passed; it handed_over text_tiers typecheck + guard set 214 passed; clippy clean; pre-push-check ok
Gate: green
Deviation: none
Found: probe struct P { name: String } fn look(p: ref P) -> i64 { return p.name.len() } fn f(t: ref P) -> i64 { return look(P { name: t.name + "!" }) }: nikaia check passes, rustc “cannot move out of t.name behind a shared reference” (lowered plus(t.name, "!")); also let t = P{..}; let a = look(if c { t } else { P{..} }); a + t.name.len() moves the owned local t into the arm (rustc borrow of moved value)
Needs: none
Changelog: An if or a match handed to a lent parameter whose arms are a view and a value made in the arm now lowers to code that compiles: every arm is lent through the call.
Owner: none
Disk freed: 0 (test cache 2.5G, 18G free; new entry over 100 MB: run-bundle/65d964130cc06fb2 293 MB)
Rs2nika: none
