mruby-compiler: convert new_nil and new_self to always use variable-sized nodes

Remove conditional var_nodes_enabled logic from new_nil and new_self functions.
These functions now directly create variable-sized AST nodes using proper
size classes and memory allocation. Remove helper functions new_nil_var and
new_self_var as they are no longer needed.

Also update codegen to handle the new variable-sized node structure:
- Add NODE_VARIABLE handling to gen_assignment function
- Fix self-method call detection in call generation
- Update assignment generation to properly handle variable-sized nil nodes

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

mrbgems/mruby-compiler/core/codegen.c

@@ -2818,7 +2818,9 @@ gen_call(codegen_scope *s, node *tree, int val, int safe)
     else if (sym == MRB_OPSYM_2(s->mrb, aref)) opt_op = OP_GETIDX;
     else if (sym == MRB_OPSYM_2(s->mrb, aset)) opt_op = OP_SETIDX;
   }
-  if (!tree->car || (opt_op == OP_NOP && node_to_int(tree->car->car) == NODE_SELF)) {
+  if (!tree->car || (opt_op == OP_NOP &&
+      node_to_int(tree->car->car) == NODE_VARIABLE &&
+      VAR_NODE_TYPE(tree->car->cdr) == NODE_SELF)) {
     noself = 1;
     push();
   }
@@ -2937,6 +2939,28 @@ gen_assignment(codegen_scope *s, node *tree, node *rhs, int sp, int val)
     codegen_error(s, "Can't assign to numbered parameter");
     break;
 
+  case NODE_VARIABLE:
+    /* Handle variable-sized nodes completely here */
+    {
+      enum node_type var_type = VAR_NODE_TYPE(tree->cdr);
+      switch (var_type) {
+      case NODE_NIL:
+        if (rhs) {
+          codegen(s, rhs, VAL);
+          pop();
+          sp = cursp();
+        }
+        /* NODE_NIL assignment is complete - just break (splat without assignment) */
+        break;
+      default:
+        codegen_error(s, "unsupported variable-sized lhs");
+        break;
+      }
+      /* Variable-sized node handling is complete - skip second switch */
+      if (val) push();
+      return;
+    }
+
   default:
     codegen_error(s, "unknown lhs");
     break;
@@ -3092,6 +3116,7 @@ gen_assignment(codegen_scope *s, node *tree, node *rhs, int sp, int val)
   case NODE_NIL:
     break;
 
+
   default:
     codegen_error(s, "unknown lhs");
     break;
@@ -6501,7 +6526,6 @@ codegen(codegen_scope *s, node *tree, int val)
     codegen_nil(s, tree, val);
     break;
 
-
   case NODE_UNDEF:
     codegen_undef(s, tree, val);
     break;

mrbgems/mruby-compiler/core/parse.y

@@ -47,8 +47,6 @@ static const char* tok(parser_state *p);
 static int toklen(parser_state *p);
 
 /* Forward declarations for variable-sized simple node functions */
-static node* new_self_var(parser_state *p);
-static node* new_nil_var(parser_state *p);
 static node* new_const_var(parser_state *p, mrb_sym symbol);
 
 /* Forward declarations for variable-sized advanced node functions */
@@ -546,10 +544,14 @@ new_ensure(parser_state *p, node *a, node *b)
 static node*
 new_nil(parser_state *p)
 {
-  if (p->var_nodes_enabled) {
-    return new_nil_var(p);
-  }
-  return list1((node*)NODE_NIL);
+  size_t total_size = sizeof(struct mrb_ast_nil_node);
+  enum mrb_ast_size_class class = size_to_class(total_size);
+
+  struct mrb_ast_nil_node *n = (struct mrb_ast_nil_node*)parser_alloc_var(p, total_size, class);
+
+  init_var_header(&n->hdr, p, NODE_NIL, class);
+
+  return cons_head((node*)NODE_VARIABLE, (node*)n);
 }
 
 /* (:true) */
@@ -729,10 +731,14 @@ new_postexe(parser_state *p, node *a)
 static node*
 new_self(parser_state *p)
 {
-  if (p->var_nodes_enabled) {
-    return new_self_var(p);
-  }
-  return list1((node*)NODE_SELF);
+  size_t total_size = sizeof(struct mrb_ast_self_node);
+  enum mrb_ast_size_class class = size_to_class(total_size);
+
+  struct mrb_ast_self_node *n = (struct mrb_ast_self_node*)parser_alloc_var(p, total_size, class);
+
+  init_var_header(&n->hdr, p, NODE_SELF, class);
+
+  return cons_head((node*)NODE_VARIABLE, (node*)n);
 }
 
 /* (:call a b c) */
@@ -1119,31 +1125,7 @@ new_op_asgn_var(parser_state *p, node *lhs, mrb_sym op, node *rhs)
 /* Variable-sized expression node creation */
 
 /* Variable-sized simple node creation functions */
-static node*
-new_self_var(parser_state *p)
-{
-  size_t total_size = sizeof(struct mrb_ast_self_node);
-  enum mrb_ast_size_class class = size_to_class(total_size);
 
-  struct mrb_ast_self_node *n = (struct mrb_ast_self_node*)parser_alloc_var(p, total_size, class);
-
-  init_var_header(&n->hdr, p, NODE_SELF, class);
-
-  return cons_head((node*)NODE_VARIABLE, (node*)n);
-}
-
-static node*
-new_nil_var(parser_state *p)
-{
-  size_t total_size = sizeof(struct mrb_ast_nil_node);
-  enum mrb_ast_size_class class = size_to_class(total_size);
-
-  struct mrb_ast_nil_node *n = (struct mrb_ast_nil_node*)parser_alloc_var(p, total_size, class);
-
-  init_var_header(&n->hdr, p, NODE_NIL, class);
-
-  return cons_head((node*)NODE_VARIABLE, (node*)n);
-}
 
 static node*
 new_const_var(parser_state *p, mrb_sym symbol)