Explicit write barrier for binding

mrbgems/mruby-binding-core/src/binding-core.c

@@ -151,6 +151,9 @@ binding_local_variable_set(mrb_state *mrb, mrb_value self)
   mrb_value *e = binding_local_variable_search(mrb, proc, env, varname);
   if (e) {
     *e = obj;
+    if (!mrb_immediate_p(obj)) {
+      mrb_field_write_barrier(mrb, (struct RBasic*)env, (struct RBasic*)mrb_obj_ptr(obj));
+    }
   }
   else {
     mrb_proc_merge_lvar(mrb, (mrb_irep*)proc->body.irep, env, 1, &varname, &obj);

src/proc.c

@@ -419,6 +419,11 @@ mrb_proc_merge_lvar(mrb_state *mrb, mrb_irep *irep, struct REnv *env, int num, c
   memmove(destlv, lv, sizeof(mrb_sym) * num);
   if (stack) {
     memmove(destst, stack, sizeof(mrb_value) * num);
+    for (int i = 0; i < num; i++) {
+      if (!mrb_immediate_p(stack[i])) {
+        mrb_field_write_barrier(mrb, (struct RBasic*)env, (struct RBasic*)mrb_obj_ptr(stack[i]));
+      }
+    }
   }
   else {
     for (int i = num; i > 0; i--, destst++) {