Fix name assignment to frozen anonymous class/module

Fix the following issues:

  A = Class.new.freeze              #=> FrozenError
  Module.new::B = Class.new.freeze  #=> FrozenError
  String::B = Module.new.freeze     #=> FrozenError

include/mruby/variable.h

@@ -117,6 +117,7 @@ MRB_API void mrb_mod_cv_set(mrb_state *mrb, struct RClass * c, mrb_sym sym, mrb_
 MRB_API void mrb_cv_set(mrb_state *mrb, mrb_value mod, mrb_sym sym, mrb_value v);
 MRB_API mrb_bool mrb_cv_defined(mrb_state *mrb, mrb_value mod, mrb_sym sym);
 mrb_value mrb_obj_iv_inspect(mrb_state*, struct RObject*);
+void mrb_obj_iv_set_force(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v);
 mrb_value mrb_mod_constants(mrb_state *mrb, mrb_value mod);
 mrb_value mrb_f_global_variables(mrb_state *mrb, mrb_value self);
 mrb_value mrb_obj_instance_variables(mrb_state*, mrb_value);

src/class.c

@@ -66,15 +66,15 @@ mrb_class_name_class(mrb_state *mrb, struct RClass *outer, struct RClass *c, mrb
     name = mrb_class_path(mrb, outer);
     if (mrb_nil_p(name)) {      /* unnamed outer class */
       if (outer != mrb->object_class && outer != c) {
-        mrb_obj_iv_set(mrb, (struct RObject*)c, mrb_intern_lit(mrb, "__outer__"),
-                       mrb_obj_value(outer));
+        mrb_obj_iv_set_force(mrb, (struct RObject*)c, mrb_intern_lit(mrb, "__outer__"),
+                             mrb_obj_value(outer));
       }
       return;
     }
     mrb_str_cat_cstr(mrb, name, "::");
     mrb_str_cat_cstr(mrb, name, mrb_sym2name(mrb, id));
   }
-  mrb_obj_iv_set(mrb, (struct RObject*)c, nsym, name);
+  mrb_obj_iv_set_force(mrb, (struct RObject*)c, nsym, name);
 }
 
 static void

src/variable.c

@@ -341,21 +341,24 @@ mrb_iv_get(mrb_state *mrb, mrb_value obj, mrb_sym sym)
 
 static inline void assign_class_name(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v);
 
-MRB_API void
-mrb_obj_iv_set(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
+void
+mrb_obj_iv_set_force(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
 {
-  iv_tbl *t;
-
-  mrb_check_frozen(mrb, obj);
   assign_class_name(mrb, obj, sym, v);
   if (!obj->iv) {
     obj->iv = iv_new(mrb);
   }
-  t = obj->iv;
-  iv_put(mrb, t, sym, v);
+  iv_put(mrb, obj->iv, sym, v);
   mrb_write_barrier(mrb, (struct RBasic*)obj);
 }
 
+MRB_API void
+mrb_obj_iv_set(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
+{
+  mrb_check_frozen(mrb, obj);
+  mrb_obj_iv_set_force(mrb, obj, sym, v);
+}
+
 /* Iterates over the instance variable table. */
 MRB_API void
 mrb_iv_foreach(mrb_state *mrb, mrb_value obj, mrb_iv_foreach_func *func, void *p)
@@ -385,10 +388,10 @@ assign_class_name(mrb_state *mrb, struct RObject *obj, mrb_sym sym, mrb_value v)
 
         if (mrb_nil_p(o)) {
           if ((struct RClass *)obj == mrb->object_class) {
-            mrb_obj_iv_set(mrb, c, id_classname, mrb_symbol_value(sym));
+            mrb_obj_iv_set_force(mrb, c, id_classname, mrb_symbol_value(sym));
           }
           else {
-            mrb_obj_iv_set(mrb, c, id_outer, mrb_obj_value(obj));
+            mrb_obj_iv_set_force(mrb, c, id_outer, mrb_obj_value(obj));
           }
         }
       }

test/t/module.rb

@@ -653,6 +653,10 @@ assert('Module#to_s') do
 
   assert_match "#<Module:0x*>", Module.new.to_s
   assert_match "#<Class:0x*>", Class.new.to_s
+
+  assert_equal "FrozenClassToS", (FrozenClassToS = Class.new.freeze).to_s
+  assert_equal "Outer::A", (Outer::A = Module.new.freeze).to_s
+  assert_match "#<Module:0x*>::A", (Module.new::A = Class.new.freeze).to_s
 end
 
 assert('Module#inspect') do