From c0fb1ccff8c34d96d72fef7befc08d245a3c9b4a Mon Sep 17 00:00:00 2001
From: nyash-codex <codex@nyash.local>
Date: Wed, 19 Nov 2025 03:37:16 +0900
Subject: [PATCH] =?UTF-8?q?fix(mir):=20Hotfix=206=20-=20Instance=20method?=
 =?UTF-8?q?=20=E3=83=91=E3=83=A9=E3=83=A1=E3=83=BC=E3=82=BF=E3=83=9E?=
 =?UTF-8?q?=E3=83=83=E3=83=94=E3=83=B3=E3=82=B0=E4=BF=AE=E6=AD=A3?=
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問題:
- setup_method_params が next_value_id() を呼んで新しい ValueId を生成
- でも MirFunction::new() で既に ValueId 0..N が予約済み
- → パラメータが %2,%3 になり、シグネチャ %0,%1 とミスマッチ

修正:
- 予約済み ValueId を直接使用 (ValueId(0), ValueId(1), ...)
- setup_function_params と同じロジックに統一

影響:
- MyBox.birth/1 のパラメータマッピングが正しくなった
- %0 = me, %1 = v として正しく MIR 生成される

既知問題:
- user-defined box の実行時問題は残存（別調査が必要）
- dev verify の NewBox→birth 警告ロジック要調査

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
---
 src/mir/builder/calls/lowering.rs | 13 ++++++++-----
 1 file changed, 8 insertions(+), 5 deletions(-)

diff --git a/src/mir/builder/calls/lowering.rs b/src/mir/builder/calls/lowering.rs
index e7c4612c..12cd7a64 100644
--- a/src/mir/builder/calls/lowering.rs
+++ b/src/mir/builder/calls/lowering.rs
@@ -7,6 +7,7 @@
 
 use crate::ast::ASTNode;
 use crate::mir::builder::{MirBuilder, MirType, MirInstruction};
+use crate::mir::{ValueId};
 use crate::mir::region::function_slot_registry::FunctionSlotRegistry;
 use super::function_lowering;
 use std::collections::HashMap;
@@ -267,16 +268,18 @@ impl MirBuilder {
         let mut slot_regs: Vec<(String, Option<MirType>)> = Vec::new();
 
         if let Some(ref mut f) = self.current_function {
-            // First parameter is always 'me'
-            let me_id = f.next_value_id();
+            // 📦 Hotfix 6: Use pre-reserved ValueIds instead of generating new ones
+            // MirFunction::new() already reserved ValueIds 0..N for parameters
+            // First parameter is always 'me' at ValueId(0)
+            let me_id = ValueId(0);
             f.params.push(me_id);
             self.variable_map.insert("me".to_string(), me_id);
             self.value_origin_newbox.insert(me_id, box_name.to_string());
             slot_regs.push(("me".to_string(), None));
 
-            // Then regular parameters
-            for p in params {
-                let pid = f.next_value_id();
+            // Then regular parameters at ValueId(1), ValueId(2), ...
+            for (idx, p) in params.iter().enumerate() {
+                let pid = ValueId((idx + 1) as u32);
                 f.params.push(pid);
                 self.variable_map.insert(p.clone(), pid);
                 slot_regs.push((p.clone(), None));