mruby-compiler: convert new_nvar to always use variable-sized nodes

Remove var_nodes_enabled conditional from new_nvar() and traditional
NODE_NVAR case from codegen. All numbered parameter operations now use
unified variable-sized node handling.

Co-authored-by: Claude <noreply@anthropic.com>

mrbgems/mruby-compiler/core/codegen.c

@@ -2940,11 +2940,6 @@ gen_assignment(codegen_scope *s, node *tree, node *rhs, int sp, int val)
     /* keep evaluation order */
     break;
 
-  case NODE_NVAR:
-    /* never happens; should have already checked in the parser */
-    codegen_error(s, "Can't assign to numbered parameter");
-    break;
-
   case NODE_VARIABLE:
     /* Handle variable-sized nodes completely here */
     {
@@ -3614,7 +3609,6 @@ codegen_masgn(codegen_scope *s, node *tree, int val)
   }
 }
 
-
 static void
 codegen_lvar(codegen_scope *s, mrb_sym sym, int val)
 {
@@ -3630,17 +3624,6 @@ codegen_lvar(codegen_scope *s, mrb_sym sym, int val)
   push();
 }
 
-static void
-codegen_nvar(codegen_scope *s, node *tree, int val)
-{
-  if (!val) return;
-  int idx = node_to_int(tree);
-
-  gen_move(s, cursp(), idx, val);
-  push();
-}
-
-
 static void
 codegen_const(codegen_scope *s, mrb_sym sym, int val)
 {
@@ -5418,8 +5401,11 @@ gen_back_ref_var(codegen_scope *s, node *varnode, int val)
 static void
 gen_nvar_var(codegen_scope *s, node *varnode, int val)
 {
+  if (!val) return;
   struct mrb_ast_nvar_node *n = (struct mrb_ast_nvar_node*)varnode;
-  codegen_nvar(s, int_to_node(n->num), val);
+
+  gen_move(s, cursp(), n->num, val);
+  push();
 }
 
 static void
@@ -6259,10 +6245,6 @@ codegen(codegen_scope *s, node *tree, int val)
     codegen_lvar(s, node_to_sym(tree), val);
     break;
 
-  case NODE_NVAR:
-    codegen_nvar(s, tree, val);
-    break;
-
   case NODE_CONST:
     codegen_const(s, node_to_sym(tree), val);
     break;

mrbgems/mruby-compiler/core/parse.y

@@ -1349,10 +1349,6 @@ new_nvar(parser_state *p, int num)
     p->nvars->car = int_to_node(nvar > num ? nvar : num);
   }
 
-  if (!p->var_nodes_enabled) {
-    return cons_head((node*)NODE_NVAR, int_to_node(num));
-  }
-
   size_t total_size = sizeof(struct mrb_ast_nvar_node);
   enum mrb_ast_size_class class = size_to_class(total_size);
   struct mrb_ast_nvar_node *n = (struct mrb_ast_nvar_node*)parser_alloc_var(p, total_size, class);