docs(phase260): checkpoint P0/P0.1 + update quick first fail

docs/development/current/main/10-Now.md

@@ -18,20 +18,26 @@
 
 ## Current First FAIL (SSOT)
 
-- **Before Phase 259 P0**: `json_lint_vm / StringUtils.is_integer/1`
-- **After Phase 259 P0**: `json_lint_vm / Main.main/0 nested-loop with break`
+- **After Phase 260 P0.1**: `core_direct_array_oob_set_rc_vm / Stage-B compile / JoinIR Pattern2 LoopBodyLocal(seg)`
 
 ### Next FAIL Details
 
-- **Test**: `json_lint_vm`
-- **Function**: `Main.main/0`
-- **Error**: `[cf_loop/pattern2] Failed to extract break condition from loop body`
-- **Pattern**: Nested loop（外側 `loop(i < cases.length())` 内で内側 `loop(j < valid.length())` + break）
+- **Test**: `core_direct_array_oob_set_rc_vm`
+- **Phase**: Stage‑B compile (`stageb_compile_to_json`)
+- **Error**: `[cf_loop/pattern2] Cannot promote LoopBodyLocal variables ["seg"] ... [pattern2/body_local_slot/contract/not_readonly]`
 - **Reproduce**:
   ```bash
-  ./target/release/hakorune --backend vm apps/examples/json_lint/main.hako
+  bash tools/smokes/v2/profiles/quick/core/core_direct_array_oob_set_rc_vm.sh
   ```
-- **Note**: is_integer/1 自体は Pattern8 で解決済み。残りは nested-loop 処理の問題（Phase 260+）
+- **Note**: Pattern2 の LoopBodyLocal promotion（A-3 Trim / A-4 DigitPos）に依存しており、Stage‑B の bundle_resolver 系のループで露出している。
+
+## 2025-12-20：Phase 260 P0/P0.1（edge-args Strangler）🚧
+
+- P0: MIR terminator の edge-args 併存導入（読む側 SSOT を `out_edges()`/`edge_args_to()` へ寄せた）
+- P0.1: legacy layout の未設定を禁止（verify fail-fast）＋ terminator 直代入を `set_terminator*()` へ寄せた
+- Commits:
+  - P0: `4dfe3349b`
+  - P0.1: `1fe5be347`
 
 ## 2025-12-21：Phase 259 P0（Pattern8 BoolPredicateScan）✅
 

docs/development/current/main/phases/phase-260/README.md

@@ -1,8 +1,15 @@
 # Phase 260: Block-Parameterized CFG（edge-args）段階導入
 
-Status: Planned  
+Status: In progress  
 Last updated: 2025-12-20
 
+## 進捗（セーブポイント）
+
+- P0（併存導入の芯）: 完了（読む側 SSOT を `out_edges()`/`edge_args_to()` に寄せた）
+  - Commit: `4dfe3349b`
+- P0.1（hardening）: 完了（legacy layout 無し禁止 + DCE/verify の参照点整理）
+  - Commit: `1fe5be347`
+
 ## 目的（P0）
 
 JoinIR→MIR の暗黙 ABI（jump_args / carriers / expr_result slot / successors）を減らし、将来的な **block-parameterized CFG**（edge-args を第一級に持つCFG）へ収束するための「大工事パート」を開始する。

src/mir/join_ir_vm_bridge/joinir_block_converter.rs

@@ -427,9 +427,10 @@ impl JoinIrBlockConverter {
                     effects: EffectMask::PURE,
                 });
 
-                // Phase 131 P2: Preserve tail-call args as jump_args metadata (SSOT for exit wiring)
+                // Phase 131 P2: Preserve tail-call args as legacy jump-args metadata (for exit wiring)
                 //
-                // Merge/ExitArgsCollector uses BasicBlock.jump_args to recover carrier/env values.
+                // The merge pipeline recovers carrier/env values from the legacy jump-args path
+                // (via BasicBlock APIs) when converting Return → Jump to the exit block.
                 // Without this, tail-call blocks look like "no args", forcing fallbacks that can
                 // produce undefined ValueIds in DirectValue mode.
                 if let Some(block) = mir_func.blocks.get_mut(&self.current_block_id) {