go version 1.6

[moguding]

Please answer these questions before submitting your issue. Thanks!

1. What version of Go are you using (go version)?
2. What operating system and processor architecture are you using (go env)?
3. What did you do?
   If possible, provide a recipe for reproducing the error.
   A complete runnable program is good.
4. What did you expect to see?
5. What did you see instead?