Result: done
Files: crates/nikaia-std/src/tools/check_core_stmt.nika crates/nikaia-std/src/tools/check_core_flow.nika crates/nikaia-std/src/tools/check_function.nika crates/nikaia-std/src/tools/lowered/check_core_stmt.rs crates/nikaia-std/src/tools/lowered/check_core_flow.rs crates/nikaia-std/src/tools/lowered/check_function.rs tests/compiler/tests/match_on_a_field_of_a_get_bound_local.nika tests/compiler/tests/match_on_a_field_of_a_get_bound_local.stdout
Commit: check: a local a get binds past a jump is a view; a match on its field borrows (#1089)
Body: The let walk already recorded let a = m.get(k) ?? <jump> in got_past_a_jump, but check_core_flow_through_a_view (which decides the & of a match’s scrutinee) did not read it, and the match m.get(k) { null => <jump> x => x } spelling was not recognised at all. Now check_core_stmt_got_by_a_match recognises that spelling (two unguarded arms: a null arm that jumps, a binding handed back as it is), the let records it in got_past_a_jump (the ?? jump form keeps its own mut path unchanged), and through_a_view takes a name in got_past_a_jump as a view, so match a.node lowers match &a.node, over a map’s or a ref Vec’s get. got_past_a_jump was never cleared between functions (a name could leak into another function’s binding of the same name); it is now cleared where lent_lets is, in check_function.nika. Row e (a.node ?? throw on such a local) already ran at 8073f652 and is kept as a test row.
Fixes: #1089
Tests: new tests/compiler/tests/match_on_a_field_of_a_get_bound_local (rows a-h plus an owned local) refused by the unfixed binary (6 x rustc E0507), passes fixed; probes a-h print 2 fixed; tests/compiler –both-settings 500 passed; it text_views stored_views tethers views_kept 67 passed; clippy 1.97 and pre-push-check green, clippy 1.99.1 green; eef3a2e7’s yaml main.nika: check clean, a scratch copy calling load once (default written as a Limits literal) builds and prints 1 (unfixed: E0507 at match a.node)
Gate: green
Deviation: none
Found: a non-ref parameter whose field a match moves out is inferred lent and lowered &A, then rustc E0507: fn owned(a: A) -> N sync throws { let node = match a.node { null => throw E { msg: "no node" } x => x } return node } called with owned(A { node: N { v: [1, 2, 3] } }) (types as in the brief’s probe), same on 8073f652’s binary
Needs: none
Changelog: A local bound by a get whose miss jumps (m.get(k) ?? throw .., or match m.get(k) { null => throw .. x => x }) is a view of the element, so a match on one of its fields borrows it instead of being refused by rustc.
Owner: none
Disk freed: 0.65 GB (clippy 1.99 target); cache target/nikaia-project-tests 3.8G, new entry run-bundle/3f8b93b88f7f213d 364 MB, disk 7.7G free
Rs2nika: none
Pushed: local 445f606452d926c412ee3e9bd8dc0fe1e6599b79
