Phase 21.6 solidification: chain green (return/binop/loop/call); add Phase 21.7 normalization plan (methodize static boxes). Update CURRENT_TASK.md and docs.

src/llvm_py/builders/function_lower.py

@@ -30,6 +30,13 @@ def lower_function(builder, func_data: Dict[str, Any]):
         # Default: i64(i64, ...) signature; derive arity from '/N' suffix when params missing
         m = re.search(r"/(\d+)$", name)
         arity = int(m.group(1)) if m else len(params)
+        # Dev fallback: when params are missing for global (Box.method) functions,
+        # use observed call-site arity if available (scanned in builder.build_from_mir)
+        if arity == 0 and '.' in name:
+            try:
+                arity = int(builder.call_arities.get(name, 0))
+            except Exception:
+                pass
         param_types = [builder.i64] * arity
         func_ty = ir.FunctionType(builder.i64, param_types)
 
@@ -67,11 +74,38 @@ def lower_function(builder, func_data: Dict[str, Any]):
     if func is None:
         func = ir.Function(builder.module, func_ty, name=name)
 
-    # Map parameters to vmap (value_id: 0..arity-1)
+    # Map parameters to vmap. Prefer mapping by referenced value-ids that have no
+    # local definition (common in v0 JSON where params appear as lhs/rhs ids).
     try:
         arity = len(func.args)
+        # Collect defined and used ids
+        defs = set()
+        uses = set()
+        for bb in (blocks or []):
+            for ins in (bb.get('instructions') or []):
+                try:
+                    dstv = ins.get('dst')
+                    if isinstance(dstv, int):
+                        defs.add(int(dstv))
+                except Exception:
+                    pass
+                for k in ('lhs','rhs','value','cond','box_val'):
+                    try:
+                        v = ins.get(k)
+                        if isinstance(v, int):
+                            uses.add(int(v))
+                    except Exception:
+                        pass
+        cand = [vid for vid in uses if vid not in defs]
+        cand.sort()
+        mapped = 0
+        for i in range(min(arity, len(cand))):
+            builder.vmap[int(cand[i])] = func.args[i]
+            mapped += 1
+        # Fallback: also map positional 0..arity-1 to args if not already mapped
         for i in range(arity):
-            builder.vmap[i] = func.args[i]
+            if i not in builder.vmap:
+                builder.vmap[i] = func.args[i]
     except Exception:
         pass