diff --git a/node.c b/node.c
index 99558319f8..4c2810b0e2 100644
--- a/node.c
+++ b/node.c
@@ -1184,6 +1184,7 @@ void
 rb_ast_mark(rb_ast_t *ast)
 {
     if (ast->node_buffer) rb_gc_mark(ast->node_buffer->mark_ary);
+    if (ast->body.compile_option) rb_gc_mark(ast->body.compile_option);
 }
 
 void
diff --git a/parse.y b/parse.y
index 0edbc565a4..ade2e0a941 100644
--- a/parse.y
+++ b/parse.y
@@ -5807,9 +5807,8 @@ yycompile0(VALUE arg)
 	if (!opt) opt = rb_obj_hide(rb_ident_hash_new());
 	rb_hash_aset(opt, rb_sym_intern_ascii_cstr("coverage_enabled"), cov);
 	prelude = block_append(p, p->eval_tree_begin, body);
-	add_mark_object(p, opt);
 	tree->nd_body = prelude;
-	p->ast->body.compile_option = opt;
+        RB_OBJ_WRITE(p->ast, &p->ast->body.compile_option, opt);
     }
     p->ast->body.root = tree;
     p->ast->body.line_count = p->line_count;