tomoaki
3bf0dee2b0
Add KeepAlive instruction to fix hidden root problem where x = null
doesn't properly drop the strong reference.
Key changes:
- Add KeepAlive { values, drop_after } instruction to MIR
- Emit KeepAlive[drop=true] in build_assignment() before variable overwrite
- Emit KeepAlive[drop=false] in pop_lexical_scope() at scope end
- VM handler: when drop_after=true, remove ALL ValueIds pointing to
the same Arc (handles SSA Copy chains)
Test results:
- weak_upgrade_fail: exit 1 ✅ (weak_to_strong returns null after x=null)
- weak_basic: exit 2 ✅ (weak_to_strong succeeds while x alive)
- quick smoke: 154/154 PASS ✅
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
27 lines
851 B
Plaintext
27 lines
851 B
Plaintext
// Phase 285 P2: WeakRef upgrade failure test (explicit drop + null observation)
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// SSOT: docs/reference/language/lifecycle.md - weak_to_strong() failure → null
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//
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// Test: weak_to_strong() fails after explicit drop (x = null)
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// Note: Uses explicit drop instead of block scope (block scope drop conformance is separate task)
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// Expected: exit 1 (weak_to_strong returns null as expected)
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// Phase 285 P2.1: FIXED with KeepAlive instruction
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box SomeBox {
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x
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}
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static box Main {
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main() {
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local x = new SomeBox()
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x.x = 123
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local w = weak x
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x = null // 明示的に strong を切る
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local y = w.weak_to_strong() // 失敗して null
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if y == null {
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return 1 // 期待通り（weak_to_strong 失敗）
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} else {
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return 0 // 予期しない成功
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}
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}
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}
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