diff --git a/NEWS b/NEWS
index 5ab46881..e0da7aa8 100644
--- a/NEWS
+++ b/NEWS
@@ -18,6 +18,7 @@
   * Added to support "value of def-expr" feature.
   * Fixed a bug which NSDate.distantFuture returns wrong value.
   * Fixed a memory leak where an exception message would be created.
+  * Optimized where it would convert type implicit using #to_str etc.
   * Improved String#to_sym performance. ~40% faster.
   * Improved performance in dispatcher. ~20% faster.
   * Improved performance where allocates internal memory of String objects.
diff --git a/vm b/vm
index 2046f7c5..3fdbf4de 160000
--- a/vm
+++ b/vm
@@ -1 +1 @@
-Subproject commit 2046f7c5f4bea3ebb39a8afd12f4a8e18fb6e83a
+Subproject commit 3fdbf4de10c736f55fd164dd707393d2fe98ab6e