wip(recv): emit_unified_call で最終LocalSSA試行（未完）

- builder_calls.rs の emit_unified_call 末尾で recv 再materialize
- しかし MIR に Copy が反映されない問題が残る
- 次: emit_instruction 側に責務を移す構造的修正へ

src/mir/builder/ssa/local.rs

@@ -1,5 +1,5 @@
 use crate::mir::builder::MirBuilder;
-use crate::mir::{ValueId, Callee};
+use crate::mir::ValueId;
 
 #[derive(Copy, Clone, Eq, PartialEq, Hash, Debug)]
 pub enum LocalKind {
@@ -38,6 +38,12 @@ pub fn ensure(builder: &mut MirBuilder, v: ValueId, kind: LocalKind) -> ValueId
             return loc;
         }
 
+        // Ensure the current basic block exists in the function before emitting a Copy.
+        // Stage-B 経路などでは current_block が割り当て済みでも、ブロック自体が
+        // function にまだ追加されていない場合があり、そのまま emit_instruction すると
+        // Copy が黙って落ちてしまう。ここで best-effort で作成しておく。
+        let _ = builder.ensure_block_exists(bb);
+
         // CRITICAL FIX: If `v` is from a pinned slot, check if there's a PHI value for that slot
         // in the current block's variable_map. If so, use the PHI value directly instead of
         // emitting a Copy from the old value (which might not be defined in this block).
@@ -96,19 +102,6 @@ pub fn field_base(builder: &mut MirBuilder, v: ValueId) -> ValueId { ensure(buil
 #[inline]
 pub fn cmp_operand(builder: &mut MirBuilder, v: ValueId) -> ValueId { ensure(builder, v, LocalKind::CompareOperand) }
 
-/// Finalize a callee+args just before emitting a Call instruction:
-/// - If Method: ensure receiver is in the current block
-/// - All args: ensure in the current block
-pub fn finalize_callee_and_args(builder: &mut MirBuilder, callee: &mut Callee, args: &mut Vec<ValueId>) {
-    if let Callee::Method { receiver: Some(r), box_name, method, certainty } = callee.clone() {
-        let r_local = recv(builder, r);
-        *callee = Callee::Method { box_name, method, receiver: Some(r_local), certainty };
-    }
-    for a in args.iter_mut() {
-        *a = arg(builder, *a);
-    }
-}
-
 /// Finalize only the args (legacy Call paths)
 pub fn finalize_args(builder: &mut MirBuilder, args: &mut Vec<ValueId>) {
     for a in args.iter_mut() {